Solar Handbook

S o l a r C o l l e c t o r

10 Industrial Parkway Woburn, MA 01801Ph. 781-721-0303 Fax 781-721-9119

www.capcosupply.com

REV. 4

Thermal Solar Table Of Contents

VITOSOL Installation Guide 1-12 VITOSOL Flat Plate Installation Instructions 13-34 Viessmann Solar Packages 35-36 Caleffi idronics 37-90 Caleffi 2-80 Solar Package 91 2-Panel 80 Gal. Tank Simulation 92-96 Caleffi 3-120 Solar Package 97 3-Panel 120 Gal. Tank Simulation 98-102 Solar Project Check List 103-104 Sizing a Solar System for DHW 105-106 SRCC Ratings 107-110 Solar Costs with Incentives Example 111 Cost Analysis versus Oil 112 Tax Incentives 113-116 Application Drawings 117-119

Installation Instructionsfor use by heating contractor

Vitosol-FModels SV, SHFlat plate solar collectors for sloped roofs, flat roofsand freestanding installation

VITOSOL-F

Read and save these instructionsfor future reference.

IMPORTANT

Vitosol 100-FModel SV1

Vitosol 200-FModel SV2

Vitosol 100-FModel SH1

Vitosol 200-FModel SH2

PleasefileinServiceBinder

5285 710 v2.0 03/2008

Notes on Installation

H The entire solar heating systemshould be installed in accordance withthe accepted rules of technology,observing all relevant accidentprevention regulations.

H Employ suitable safety measures toprevent falls, falling objects and roofdamage due to insufficient loadbearing capacity, e.g. by means ofscaffolding, ladders, cable ties etc.

H The collectors must be securelymounted so that the mountings canwithstand intense wind conditions.

H Use only stainless steel screws andbolts when fastening mountingbrackets or frames.

H Although the glass collectors surfacesare hail-proof, Viessmann recomendsusers to include storm coverage intheir building insurance. Our warrantydoes not cover storm related damage.

H The collectors should, as far aspossible, be oriented towards thesouth. Solar system performancedrops off significantly if collectorsface more than 50° off south.

H The collectors should be mountedlevel, or with a slight ascending slope(approx. ½” / 10mm) towards thehigh point of the piping, so thatcomplete venting is assured.

H An air vent valve (c/w shut-off valve)should be installed at the highestpoint of the solar heating system.

H Filling the solar heating system withViessmann heat transfer fluid“Tyfocor-HTL” is highlyrecommended. Tyfocor-HTL issupplied pre-mixed and water mustnot be added.Other heat transfer fluids may besuitable if they have the sametemperature range (-35°C to 170°C)and are non-toxic.

H The piping inside and outside thebuilding should be insulated to avoidheat loss. Use only high temperatureresistant pipe insulation.

Collector Location

Please refer to the Vitosol System Design Guidelines, Part No. 5167 156 for detailed information on the optimumalignment and inclination of solar collectors.

Optimum alignment and inclinationThe solar collector provides the highestsolar yield over an annual average whenfacing south with an inclination ofapprox. 30 to 45 degreesto the horizontal plane. However, theinstallation of a solar heating system isstill viable even when the installationdeviates quite significantly from theabove (south-westerly to south-easterlyalignment, 25 to 55 degreesinclination).

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Use only Viessmann suppliedmounting clips and mountinghardware. Never drill or screwdirectly into collector side frames.

CAUTION

Pool water or potable water cannotbe pumped directly through theVitosol collectors. Damage tocollectors caused by corrosion, freezedamage, or scaling will void warranty.

CAUTION

Installation on Sloped Roofs

8

Overview of System Components

Sloped roof mounting hardware

Roof bracketClamping bracketJoining element for mounting railMounting rail, 46¼” / 1175 mm or91¾” / 2330 mmWasher, Ø ¼” / 8.4 mmHexagon screw, M 8 x 10Mounting plateClamping bracketLocking bolt w/ threaded studHexagon nutZinc plated countersunk screws,3.1” / 80 mm

Hydraulic connection accessories forone panel array

Interconnection pipes (7248 239)

General Connection Set (7248 240)consists of:

Pipe clipMounting rail end capConnecting pipePlugsCompression fitting (elbow),Ø ¾” / 22 mm, 90°¾” x 4” copper adaptor (part ofinstallation fitting set 7134 449)

Accessories for one solar heatingsystem

Sensor Well Set (7174 993)consists of:

Compression fitting (tee), Ø ¾” /22 mmSensor wellStrain relief fittingInsulation

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Collector, Model SV1 and SV2Collector, Model SH1 and SH2

1056

1056

2380

2380

Installing the Mounting Frames

Install the panel array level or slightly inclined (approximately ½” / 10 mm) towards the connection side to ensure completeventing. Always locate an air vent at the highest point in the piping.

Attaching roof brackets on shingled roof

1. The roof brackets should be laidout as close as possible to thedimensions shown in the chart onpage 10 for SV collectors, and page11 for SH collectors.

2. Locate the roof joist by tappingalong the roof to find its generallocation (stud finders do not workwell through shingles and roofsheathing).

3. Pry up the shingles and drill smallpilot holes to locate exact locationof roof joist. If necessary, checkwhere pilot hole is coming throughroof from inside of attic.

4. Drill pilot holes into center of joist asshown. Fill the pilot holes and coatthe bottom of roof bracket withsilicone sealant.

5. Attach bracket to roof joist usingappropriate stainless steel lag bolts

or screws (field supplied). Lagbolt should penetrate the roof joistat least 2½” / 64 mm.

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Correct Incorrect

Source: CANSIA

Source: CANSIA

Lagbolt

WasherMountingbracket

Siliconesealant

Minimum6.3 cm /2.5 in

Too closeto edge

Drill within0.2” / 5 mmof center

The roof bracket must be securelyattached to the roof joist of thestructure. Only use stainless steelattachment screws.

CAUTION

The 3.1” / 80 mm screws suppliedwith the mounting kit may not besufficient length for some roofstructures. The installer must ensurescrews will penetrate roof joistsufficiently, and if not, must providelonger screws or lag bolts.

CAUTION


10

Installing the Mounting Frames (continued)

Installation dimensions for ten SV collector panels

6. Re-apply shingles, if required, andensure all roof penetrations arethoroughly sealed with siliconesealant.

7. Continue with mounting railinstallation on page 12.

Dimensions for Model SV collectors

Number 1 2 3 4 5 6 8 10

Dim. A mminches

101940

101940

101940

101940

101940

101940

101940

101940

Dim. B mminches

–– –– 107742½

107742½

107742½

107742½

107742½

107742½

Dim. C mminches

39.51½

68.52¾

793

793

89.53¼

89.53½

1004

1104½

Dim. D*1 mminches

101940

A

203880¼

A+A

3115122½

A+B+A

4192165

A+2xB+A

5269207½

A+3xB+A

6346249¾

A+4xB+A

8500334½

A+6xB+A

10654419½

A+8xB+A

Dim. E mminches

109843¼

217585½

3273128¾

4350171¼

5448214½

6525256¾

8700342½

10875428

Dim. F mminches

87.53½

87.53½

984

984

108.54¼

108.54¼

1194¾

129.55

*1 For static reasons, maintain the stated sequence. Maintain the dimensions A and B as far as possible. Roof brackets may also be offsetif you need to locate roof joist. However, always maintain the overall dimension.

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36¼” /923 mm

16” /154 mm

36¼” /923 mm

36¼” /923 mm

75” - 82½”1900 - 2100 mm

General Information

Notes on Installation

H The entire solar heating systemshould be installed in accordance withthe accepted rules of technology,observing all relevant accidentprevention regulations.

H Employ suitable safety measures toprevent falls, falling objects and roofdamage due to insufficient loadbearing capacity, e.g. by means ofscaffolding, ladders, cable ties etc.

H The collectors must be securelymounted so that the mountings canwithstand intense wind conditions.

H Use only stainless steel screws andbolts when fastening mountingbrackets or frames.

H Although the glass collectors surfacesare hail-proof, Viessmann recomendsusers to include storm coverage intheir building insurance. Our warrantydoes not cover storm related damage.

H The collectors should, as far aspossible, be oriented towards thesouth. Solar system performancedrops off significantly if collectorsface more than 50° off south.

H The collectors should be mountedlevel, or with a slight ascending slope(approx. ½” / 10mm) towards thehigh point of the piping, so thatcomplete venting is assured.

H An air vent valve (c/w shut-off valve)should be installed at the highestpoint of the solar heating system.

H Filling the solar heating system withViessmann heat transfer fluid“Tyfocor-HTL” is highlyrecommended. Tyfocor-HTL issupplied pre-mixed and water mustnot be added.Other heat transfer fluids may besuitable if they have the sametemperature range (-35°C to 170°C)and are non-toxic.

H The piping inside and outside thebuilding should be insulated to avoidheat loss. Use only high temperatureresistant pipe insulation.

Collector Location

Please refer to the Vitosol System Design Guidelines, Part No. 5167 156 for detailed information on the optimumalignment and inclination of solar collectors.

Optimum alignment and inclinationThe solar collector provides the highestsolar yield over an annual average whenfacing south with an inclination ofapprox. 30 to 45 degreesto the horizontal plane. However, theinstallation of a solar heating system isstill viable even when the installationdeviates quite significantly from theabove (south-westerly to south-easterlyalignment, 25 to 55 degreesinclination).

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Use only Viessmann suppliedmounting clips and mountinghardware. Never drill or screwdirectly into collector side frames.

CAUTION

Pool water or potable water cannotbe pumped directly through theVitosol collectors. Damage tocollectors caused by corrosion, freezedamage, or scaling will void warranty.

CAUTION


12

Installing the Mounting Frames (continued)

Installing the mounting rails

Turn the T-slot bolts 90° for allinstallation steps.

1. Secure the joining elements intothe mounting rails .

Make sure the mounting rail profile is asshown. Failure to install the mountingrail correctly will not allow propermounting plate connection.

2. Secure the mounting rails to the roofbracket. The locking bolt must beturned 90°.

Ensure the upper and lower mountingrails are square before tightening thelocking bolts. Measure from oppositecorners of the top and bottom rails toensure that array is square.

3. Hook the mounting plates intolower mounting rails according tothe dimensions shown in theillustrations on pages 10 and 11.

Make sure the mounting plate isinstalled with the short bent edgeconnecting onto the bottom of thecollector.

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2.

1.

3.

Roof brackets

IMPORTANT

IMPORTANT

IMPORTANT

IMPORTANT


13

Installing the Solar Collectors

Rating plate(must be on the outside of theouter collectors)

Interconnecting pipes must be free fromdamage and contamination. Lubricate allplug-in joints (O-ring seals) on thecollectors. Use only the special greasesupplied with the connection set.

On the first and last collector, the sideto which the rating plate is attachedmust be on the outside. Ensure thatdimension “r” is maintained for first andlast collector.

1. Hook the collector into its mountingplates and lay down onto themounting rails .

2. Secure the collector with fourclamping brackets onto themounting rails. Tighten the twoouter clamping bolts only. Turn thegrooved bolt 90°.

3. Insert the connecting pipe until itbottoms out inside the collectorconnections.

Ensure interconnection pipe is centeredbetween collector.

Number of collectors 1 2 3 4 5 6 8 10

Dimension rSV collector

inchesmm

0.821

0.821

1.231.5

1.231.5

1.742

1.742

2.152.5

2.563

Dimension rSH collector

inchesmm

0.821

1.231.5

1.742

2.152.5

2.563

2.973.5

3.794.5

4.5115.5

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3.

3.

4x8.

1.

5.

4.

2.

¾” /21 mm

Do not stand on the collectors.

CAUTION

IMPORTANT

IMPORTANT

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IMPORTANT

4. Position the second collector as instep 1.

5. Carefully push the second collectoragainst the first and insert theconnecting pipes until they arecentered between the collectors.Distance from the lower edge of theinstalled collector should be¾” / 21 mm.

6. Install all additional collectors.

Continued on following page.


14

Installing the Solar Collectors (continued)

7. Tighten all clamping brackets.

8. Press the cover caps (part of theconnection set) into the mountingrails.

9. Remove all labels.

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Arrows on the first and last collectorin a series must point towards theoutside.

CAUTION

Viessmann strongly recommends notremoving the cover foil from thecollectors until after initial start-up inorder to prevent overheating.

CAUTION

Installation on Flat Roofsor Freestanding Installation

15

Overview of System Components

Legend:

Collector supportCross braceAdjustable support, lower partAdjustable support, upper part (twopart)Washer, Ø 0.33” / 8.4 mmHexagon nut, M8Hexagon screw, M8 x 20Support rail (only for flat roofs withgravel filling)Retaining plateClamping bracketConnecting braceConnecting ties

Collector model a b

SV inchesmm

63.81620

70.71795

SH inchesmm

28.4722

35.3897

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3¼” / 80 mm

4”/

100mm

3”/

75mm

2” / 50 mm

Ø 0.43” /11 mm

a b


16

Determining the Collector Row Distance “z”

Legend:z=Collector row distanceh=Collector heightα=Collector angle of inclinationβ=Solar angle

When installing several collectors inseries, maintain a distance of “z”.

Example:

Model SVToronto is located at approx. 43°latitude.

1. Determine the angle of the sun β.This should be chosen so that themidday sun December 21 falls on thesecond row of collectors withoutbeing obstructed by shadows.

Solar angle β:β=90 °-23.5°-latitude(23.5° should be accepted asconstant value for northern latitudes)

β=90 °-23.5°-43°=23.5°

2. Calculating dimension “z”:h= 2380 mm (for model SH use1056 mm)α= 45°β= 23.5°

z=2380 ⋅ sin(180°− (45°+ 23.5°))sin 23.5°

z=2380mm ⋅ sin111.5°sin23.5°

z=5553mm / 218.6”

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z

h h

z=

h

IMPORTANT


17

Installing the Collector Supports and Adjustment of the Angle of Inclination

1. Secure the lower adjustable supportwith the cross brace.

2. Secure the upper and loweradjustable supports in accordancewith the required angle of inclination.

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1.

2.


18

Installing Freestanding Installation (on substructures)

Understructure

1.Mount the understructure (to beprovided on site), e.g. U-channels, atright angles to and level with theinstallation orientation of thecollectors according to thedimensions shown in the drawing.

2. Position and align the collectorsupport frames according to thedimensions shown in the drawing andsecure them to the understructureusing stainless steel bolts (suppliedby others). Use mounting plates astemplates for drilling holes.

3. Secure retaining plates to thebottom of all collector supports; donot tighten screws yet.

4. Secure braces onto the retainingplates between the second and third,the fourth and fifth supports etc.Tighten all screws.

5. Secure two connecting tiesdiagonally side by side to theadjustable supports, respectively forbetween one and six collectors.

Note:Only one connecting tie is suppliedfor 1 to 6 collectors, two connectingties for 7 to 10 collectors.

6. For added stability, attach connectingties to each other where theyintersect, using field supplied screwor bolt.


Collector model X Y

SV inchesmm

23.5595

18.9481

SH inchesmm

75.61920

18.9481

8,5

4x

2.

3.

4.

5.

6.

X

Y

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Any welds or connections to theexisting substructure must besupervised by a professionalstructural engineer.

CAUTION


19

Installing Freestanding Installation (on substructures)

Legend

Collector connectionSpacer lip of the connecting braceRating plate

7. Position the first collector into theretaining plates and push right up tothe spacer lip of the connectingbrace.

Install the collector panel so that therating plate side of the first and lastcollector is on the outside (notesticker)! If only one collector is to beinstalled, connect the piping oppositethe nameplate side.

8. Insert the interconnecting pipes asfar as possible into the collectorconnections.


9. Carefully push the next collector upto the spacer lip and insert theinterconnecting pipes as far aspossible.

Ensure interconnection pipe is centeredbetween collectors.

10. Click clamping brackets into thecollector edge at the top of allsupports.

11. Secure the connecting brace turnedby 180° to the next brace usingthe clamping brackets between thesecond and third, the fourth andfifth supports, etc.

12. Tighten all screws.

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9.1”

7.

8.

9.

10.

11.

IMPORTANT

IMPORTANT

IMPORTANT


20

Installing a Freestanding Installation (with weight inserts)

1. Observe the max. load and distancefrom the edge of the roof for on-sitesubstructure.

2. Remove any gravel etc. from theinstallation area, cover the surfacewith protective building mats or foaminsulation and position concrete slabson top of the mats or insulation.

3. Secure the support cross brace (useas drilling template) onto theconcrete slabs (bolts supplied byothers).

4. Secure retaining plates to thebottom of all collector supports; donot yet tighten screws.

5. Secure connecting braces ontothe retaining plates between thesecond and third, the fourth and fifthsupports etc.Tighten all screws.


Collector model X Y

SV inchesmm

23.5595

18.9481

SH inchesmm

75.61920

18.9481

3.

4.

5.

4x

Y

X

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A structural engineer must beconsulted to ensure that the existingroof structure is capable of carryingthe additional weight of thecollectors, insert weights and supportslabs.

CAUTION


21

Installing Freestanding Installation (with weight inserts)

6. Secure the support rails between thecross braces.

Note:With an angle of inclination of 25 and30°, the front support rails can besecured in the center.

7. Apply weights (see tables onpage 23).

8. Secure two connecting tiesdiagonally side by side to theadjustable supports (for up to sixcollectors).

9. For added stability, attach connectingties to each other where theyintersect, using field supplied screwsor bolts.

8,5

6.

7.

8.

9.

weight insert

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22


Collector connectionSpacer lipRating plate

9. Position the first collector into theretaining plates and push right up tothe spacer lip of the connectingbrace.Center the distance when fitting onlya single collector.

Install the collector panel so that therating plate side of the first and lastcollector is on the outside (notesticker)! If only one collector is to beinstalled, connect the piping oppositethe nameplate side.

10. Insert the interconnecting pipesas far as possible into the collectorconnections.


11. Carefully push the next collector upto the spacer lip and insert theinterconnecting pipes as far aspossible.

Ensure interconnection pipe is centeredbetween collectors.

12. Click clamping brackets into thecollector edge at the top of allsupports.

13. Secure the connecting braceturned by 180° to the next braceusing the clamping bracketsbetween the second and third, thefourth and fifth supports, etc.

14. Tighten all screws.

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9.

13.

10.

12.

11.

¶ 232 mm /9.1”

IMPORTANT

IMPORTANT

IMPORTANT



23


Model SV Secure against slipping*1 Secure against lifting*2

Installation height aboveground level

ft.m

<26< 8

26 - 668 - 20

66 - 32820 - 100

<26< 8

26 - 668 - 20

66 - 32820 - 100

Required weight at 25° lbs*3

kg694315

1221554

1748793

317144

670304

1025465

Required weight at 45° lbskg

1120508

1856842

26741213

282128

493224

762346

*1 Securing against slipping requires no additional attachment to roof.*2 Securing against lifting requires additional attachment to roof or structure with wires or cables.*3 Weights listed are the total of the insert weights and support slabs.

Model SH Secure against slipping*1 Secure against lifting*2

Installation height aboveground level

ft.m

<26< 8

26 - 668 - 20

100<26< 8

66 - 32820 -

26 - 668 - 20

66 - 32820 - 100

Required weight at 25° lbs*3

kg712323

1237561

1764800

342155

695315

1049476

Required weight at 45° lbskg

1085492

1863845

26411198

291132

560254

827375

*1 Securing against slipping requires no additional attachment to roof.*2 Securing against lifting requires additional attachment to roof or structure with wires or cables.*3 Weights listed are the total of the insert weights and support slabs.

Supply and Return Piping Configuration

Vitosol 100Models SV, SH

Installation of collectors, connection onalternate sides, max. 12 collectors.

max. 12B

A

CØ 28x1

Ø 28x1

Installation of collectors, single-sidedconnection, max. 10 collectors.

max. 10B

AC

Ø 28x1

Ø 28x1

Supply (hot)ReturnAir vent valve (shut-off type)

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Hydronic Connections

24

Installing the Connection Set and Collector Temperature Sensor

When assembling the locking ringcompression fitting, observe thefollowing:H All pipe ends must be square anddeburred.

H Push the union nut and the lockingring onto the pipe adaptor and lightlylubricate the threads with oil.

H Push the pipe into the compressionfitting as far as it will go.

H Initially, turn the union nut by hand,then tighten with an open endedspanner by another ¾ turn.

Do not use annealed copper pipes withcompression fittings.

1. Insert the plug until it bottoms out,and secure with hose clip .

2. Insert the connection pipes untilthey bottom out and secure them withhose clips .

3.Fit the elbow onto the returnconnector at the bottom of thecollector.

4.Fit the tee onto the supplyconnector at the top of the collector.

5. Insert the sensor well into the tee. Hold the tee tightly.

6. Insert the strain relief fitting into thesensor well.

7. Insert the collector temperature sensor(supplied with solar controller) until

it bottoms out inside the sensor well,and secure with strain relief fitting.

8. Insert the 4” copper adaptor intothe compression fittings and make theconnection between the panel array andthe supply and return piping.

9. Install the insulation and securewith adhesive on its cut faces.

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2.

1. 6.

7.

9.

3.3.3.2.

5.

4.8.

1.

Hydronic Connections /Appendix

25

p

Collector Supply and Return Piping

H For the piping connecting thecollectors to the Solar Diviconpumping station, Viessmannrecommends the use of commercialcopper pipe and bronze fittings, ornon-galvanized steel pipe. PEX orother plastic pipes are not suitable forsolar collector supply and returnpiping.

H Use only high temperature solder orbrazing material when connecting thecopper pipes in the collector piping.The melting temperature should beabove 450 °F / 232 °C.

HWhen laying out the collector array,ensure that the system can “breathe”properly. Do not route pipes above thecollector array.

Refer to the Vitosol SystemDesign Guidelines forrequired flow rates and pipesizing parameters forVitosol-F collectors.

Solar collectorSolar-Divicon (pumping station)Collecting tankExpansion vesselSolar manual filling pumpSystem fill manifold valveScrew-in elbow, comes withsensor wellDual-mode DHW tank

I Tank temperature sensorAir separator

Solar control unitFlexible connection pipe (optional)Collector temperature sensor

Fast air vent, c/w shutoff valve *1

R Return to collectorS Supply from collector

*1 Install at least one air vent valve at thehighest point of the system.

Refer to the Vitosol SystemDesign Guidelines for moreinformation on otherinstallation examples andsystem types.

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Do not use galvanized pipes,galvanized fittings or graphitizedgaskets, or any type of plastic pipes.

CAUTION

Sample System Layout

S R

TT

T

I

DCW

DHW

The domestic hot water temperaturemust be limited to 140°F / 60°C byinstalling a mixing device, e.g. athermostatic anti-scald mixing valve.

WARNING

Appendix

26

System Installation

Please refer to the Vitosol”System Design Guidelines”for supplementary notes oninstallation examples andsystem types.

H The connecting lines must be pressureand temperature-resistant (observethe max. shutdown temperature ofthe collector).

H To guarantee the satisfactoryoperation of the solar heating system,install the pipes so that complete airventing is assured.

HAt least one fast-acting air vent withshut-off valve must be installed at thehighest point of the system.Install an air separator at an acces-sible point in the piping (e.g. in theflow of the solar circuit, upstream ofthe inlet to the indirect coil of thedomestic hot water tank).

H The system must be equipped with anexpansion tank, safety valve andcirculation pump.

H The Solar-Divicon is equipped with asafety valve designed for max. 87psig / 6 bar.

HUse only a diaphragm expansion tankthat is suitable for the application as asolar expansion tank.

H The expansion tank must be approvedfor use in a solar heating system andmust be connected via a heatinsulating loop.The diaphragms and seals of theexpansion tank and the safety valvemust be suitable for the heat transfermedium.

Please refer to the ”ServiceInstructions” in order tocalculate the inlet pressureof the diaphragm expansionvessel.

H Before filling system with solar heattransfer fluid, thoroughly flush andclean piping system to remove all dirt,oils, flux and solder residue.

H Fill the solar heating system withViessmann heat transfer medium”Tyfocor-HTL”. The “Tyfocor-HTL” issupplied as a premixed glycol/watersolution and must not be mixed. Theblow-off and discharge pipes must berun to an open container capable ofaccommodating the total capacity ofthe collectors.

H Prior to installing pipe insulation, run astranded and protected 18/2 AWGlow voltage sensor wire from the solarcontroller to the collector sensor well.Ensure all wire connections aresoldered and sealed with heat shrinksleeve connectors (see illustrationbelow). Cover all wire andconnections with insulation andjacket.

*1E.g. HT/Armaflex (temperature resistant up to 175 ºC) supplied by Armstrong Insulation Products

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Use only red bronze fittings, brassfittings and copper piping.Do not use galvanized pipes,galvanized fittings, graphitizedgaskets or any type of plastic pipe.

CAUTION

Do not carry out any soldering workat or near the collector.

CAUTION

Components used must be resistantto the heat transfer medium.Insulation of external piping must beresistant to temperature*1, UVradiation and to destruction by birds(e.g. through the use of metalsheathing).

CAUTION

Twisted and soldered

Heat shrink sleeve

Heat lightly

Source: CANSIA

Appendix

27

Initial Start-up

CollectorPressure relief valveSolar-DiviconDiaphragm expansion vesselHigh-limit safety cut-outDHW tankAir vent c/w shut-offOverflow container

T Temperature sensors

The collector circuit must be protectedin such a way that at the highestpossible collector temperature(shutdown temperature) no heattransfer fluid can escape from thesafety valve, or the air vent.This is achieved by the appropriatesizing of the expansion tank andmatching of the system pressure.

Under cold fill conditions, a minimumstatic pressure must be maintained. Itcan be calculated by the following:22 psig +0.45 psig x_____h(ft.)or1.5 bar + 0.1 x_____h(m)

Commissioning and Adjustment

For commissioning of the solar heating system, refer to the Vitosol Service and Operating Instructions.

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IMPORTANT

The pressure relief valve must be pipedto the overflow container or drain at alltimes, since excessively hot fluid candischarge from the system.

CAUTION

After de-aeration, the air vent c/wshut-off at top of system must beclosed. To protect the solar systemfrom overheating in the summer, e.g.during the holidays, do not shut down.

CAUTION

Viessmann Solar PackagesSingle Tank System Package #1

Qty Item # Description2 7248-395 VISTOL 100-F, FLAT PLATE COLLECTOR1 7248-239 INTERCONNECTION PIPES BETWEEN COLLECTORS1 7248-240 GENRAL CONNECTION SET1 7174-993 SENSOR WELL SET1 Z003-098 MOUNTING HARDWARE1 7134-449 INSTALLATION FITTINGS SET1 7134-799 SOLAR DIVICON PUMPING STATION1 7134-448 VITOCELL-B 100, STEEL TANK W/ENAMEL FINISH1 7134-450 BASIC SOLAR CONTROL GL301 7248-242 SOLAR EXPANSION TANK1 7316-789 FAST AIR VENT1 7316-098 TYFOCOR-HTL1 NA3540 SOLFLEX CONNECTION PIPING 50' INSULATED

Single Tank System Package #2

Qty Item # Description1 SK00252 VITOSOL 300-T SP3 SERIES1 7188-914 VITOSOL 300 GENERAL CONNECTION SET1 Z003-335 MOUNTING HARDWARE FOR VITOSOL 3001 7134-449 INSTALLATION FITTINGS SET1 7134-799 SOLAR DIVICON PUMPING STATION1 7134-448 VITOCELL-B 100, STEEL TANK W/ENAMEL FINISH1 7134-450 BASIC SOLAR CONTROL GL301 7248-242 SOLAR EXPANSION TANK1 7316-789 FAST AIR VENT 1 7316-098 TYFOCOR-HTL 1 NA3540 SOLFLEX CONNECTION PIPING 50' INSULATED

Viessmann Solar PackagesRetrofit Preheat System #1

Qty Item # Description2 7248-395 VITOSOL 100-F SERIES, FLAT PLATE COLLECTOR1 7248-239 INTERCONNECTION PIPES VITOSOL 100-F & 200-F1 7248-240 GENERAL CONNECTION SET VITOSOL 100F & 100F1 7174-993 SENSOR WELL SET1 Z003-098 MOUNTING HARDWARE VITOSOL 1001 7134-449 INSTALLATION FITTINGS SET1 7134-799 DIVICON PUMPING STATION1 7134-162 CVA 79 GAL. DHW TANK1 7175-213 1" BRASS ELBOW1 7134-450 BASIC SOLAR CONTROL GL301 7248-242 SOLARE EXPANSION TANK1 7316-789 FAST AIR VENT1 7316-098 TYFOCOR-HTL SOLAR FILL1 NA3540 SOLFLEX CONNECTION PIPING 50' INSULATED

Retrofit Preheat System #2

Qty Item # Description1 SK00252 VITOSOL 300-T SP3 SERIES1 7188-914 300 GENERAL CONNECTION1 Z003-335 MOUNTING HARDWARE FOR SITOSOL 3001 7134-449 INSTALLATION FITTINGS SET1 7134-799 SOLAR DIVICON PUMPING STATION1 7134-162 CVA 79 GAL. DHW TANK1 7175-213 1" BRASS ELBOW1 7134-450 BASIC SOLAR CONTROL GL301 7248-242 SOLAR EXPANSION TANK1 7316-789 FAST AIR VENT1 7316-098 TYFOCOR-HTL SOLAR FILL1 NA3540 SOLFLEX CONNECTION PIPING 50' INSULATED

3

Solar energy has been used in North American buildings for decades. The first commercial solar water-heating device sold in the United States was patented in 1891. However, widespread use of solar energy in North America did not transpire because fossil fuels were readily available and relatively inexpensive throughout the industrial expansion period following World War II.

This situation quickly changed in the later 1970s following the Arab oil embargo. At that time, scores of manufacturers delivered products to the North American market to capitalize on the fervor to replace conventional energy sources with renewable energy. Although some of the solar heating and domestic hot water systems installed during this time are still functioning today, many have long since failed, been abandoned or were removed.

The lack of standards and regulation during America’s first “solar era” allowed previously untested hardware and design concepts to quickly enter the market. Government tax incentives stimulated this trend. The market enjoyed rapid growth during the early 1980s and then slowly succumbed to a combination of market forces (expiration of government tax credits and declining energy prices), as well as failure of some products to withstand the test of time. Although a few pockets of activity remained for solar pool heating and domestic water heating in the sunny southern markets, widespread national interest in solar heating was virtually non-existent during the late 1980s and 1990s as North Americans remained complacent in the face of low energy prices

TIMES HAVE CHANGED: Today, North Americans are facing some of the largest energy price increases in history. Crude oil is selling at record levels, and energy cost reduction has again become a high priority for homeowners as well as commercial building owners. The rapid expansion of solar heating technology in Europe is quickly making its way to North America and other areas of the world. Ecological concerns over global warming, as well as national security issues associated with oil importation, are also factoring into energy supply decisions. In short, North America and other industrialized countries are poised to enter an era where energy conservation and use of renewable energy sources will play a major part in their future prosperity.

Here are a few facts that help us realize the potential impact of renewable energy, now and in the future:

• In one second the sun releases more energy than has been used by mankind since the beginning of recorded history.

• In one hour more sunlight falls on the earth than what is used by the entire population in one year.

• In 2006 the renewable energy industries in the United States generated nearly $40 billion in gross revenue, while creating nearly 194,000 jobs. * Source: Management Information Services, Inc. and American Solar Energy Society, 2007.

• A major international oil company predicts that renewable iiiienergy will supply 50% of the world energy by 2040.

Source: NASA

WHAT'S NEW UNDER THE SUN?

4

In the years since the first North American solar era, manufacturers, both domestic and abroad, have significantly refined product offering. Modern materials combined with new production methods now provide products with long service lives. Improved control systems provide greater solar collection efficiency. Modular piping systems speed installation and reduce “one-of-a-kind” installations. In short, North Americans are poised for a new “sunrise” in the use of solar energy.

This issue of idronics will introduce you to the basic terminology and system concepts for modern collection and usage of solar energy. Although solar energy usage will be briefly discussed in a wide context, the bulk of the discussion focuses on active solar thermal applications.

CHARACTERISTICS OF SOLAR RADIATION: Technically, solar radiation is a form of electromagnetic radiation that’s fundamentally similar to radio waves, X-rays, and even “radiant heat” emitted by a warm floor. Although solar energy is produced by nuclear reactions at the sun, its transmission through space to earth has nothing to do with nuclear radiation.

What distinguishes solar radiation from other types of electromagnetic radiation is its wavelength. Approximately half of the energy in solar radiation lies within wavelengths that can be sensed by the human eye (e.g., visible light). The remaining energy lies in the infrared and ultraviolet portion of the electromagnetic spectrum, as shown in figure 3.

The intensity of solar radiation just outside the earth’s atmosphere is approximately 429 Btu/hr/ft2. This is more than 10 times the typical maximum output of a radiant floor panel. However, the intensity of this radiation is

significantly reduced before it reaches the earth’s surface due to absorption by gases, vapors and dust particles in the atmosphere. Geographic location on the earth, as well as time of day and time of year, greatly affects the intensity of solar radiation reaching the earth’s surface. Figure 4 shows the intensity of clear day solar radiation on a south-facing surface sloped at 40º above horizontal and located at 40º north latitude.

On a clear day, solar radiation is most intense at solar noon (e.g., that time of day when the sun is highest in the sky and directly above a polar north/south line).

Before striking the earth’s atmosphere, solar radiation travels in straight paths. This is called “direct” solar radiation. On a clear day, the majority of solar radiation striking the earth’s surface is direct radiation. Because it

Radio Microwave Infrared Visible Ultraviolet X-ray Gamma Ray

10 3 7 10 7 4 10 7 10 87 10 7 4 10 71 10 3>1 10 8 10 12<10 12

approximate wavelengths (meters)

The Electromagnetic Sprectrum

solar spectrum ranges from wavelengths of approximately 0.2 to 2.6 micrometers

12 1 2 3 4 5 6 7111098765

100

200

300

400

solar

noon

0

winter

Figure 3

Figure 4

5

travels in straight lines, direct radiation is easy to reflect using polished silver or aluminum surfaces, or to focus using parabolic mirrors.

If there were no atmosphere, nearly all the solar radiation reaching the earth’s surface would be direct radiation. However, the gas and vapor molecules in the atmosphere create a very different scenario. They reflect a significant portion of the incoming direct radiation in every direction. The result is called “diffuse” solar radiation. Its presence is the reason we see the sky and objects around us much differently than how objects are seen in space where no atmosphere exists. The vast majority of solar radiation reaching the earth’s surface on cloudy days is diffuse radiation. Because diffuse radiation comes from the entire sky dome above us, it cannot be easily focused using mirrors or other reflecting surfaces.

SOLAR ANGLES: The earth revolves once each day around an axis that passes through the North and South poles. That axis is tilted 23.44º with respect to the orbital plane of the earth around the sun, as shown in figure 5.

The tilt of the earth’s axis is called the declination angle.It’s the reason that day length changes as the earth makes its annual orbit around the sun. It also significantly affects

the intensity of solar radiation striking a fixed surface at any location on earth. We observe this effect as a change in the sun’s path across the sky, as seen in figure 6.

The sun’s position in the sky can be precisely described using two simultaneously measured angles. The solaraltitude angle is measured from a horizontal surface up to the center of the sun. The solar azimuth angle is measured starting from true north (0º) in a clockwise direction (i.e., true south would have a solar azimuth of 180º). These angles vary continuously as the sun moves across the sky. At any given time they are also different

fall equinox

Sept 22/23

spring equinox

March 20/21

summer solstice

June 20/21

winter solstice

December 21/22

declination

angle

Earth's yearly orbit

around the sun

tropic of capicorn

tropic of cancer

N

S

N

S

N

S

N

S

Figure 5

East

West

NorthSouth

Mar. 20/21

Sep. 22/23

(equinox)

June 20/21

(summer solstice)

Dec. 21/22

(winter solstice)

ALT

AZI

polar N/S line

AZI = solar azimuth angle

ALT = solar altitude angle

Figure 6

6

Source: National Geophysical Data Center

Figure 7

at different latitudes and longitudes. These angles have been precisely measured, and when needed, can be calculated for any time and location on earth. Figure 7 shows a solar path diagram indicating the solar altitude and azimuth angles for Milwaukee, Wisconsin, at 42.9º North Latitude. The calculator at the following Web site can be used to generate a solar path diagram for any location or time: http://solardata.uoregon.edu/SunChartProgram.html.

LOCATING TRUE SOUTH:Solar azimuth angles are always referenced to a “true” north line. This is a line at the earth’s surface that’s exactly parallel with the earth’s polar axis. Because the earth’s magnetic field is not aligned parallel with its polar axis, there are locations within the continental United States where the needle of a compass can point as much as 20º east or west of a true polar North/South line.

The isogonic chart shown in figure 8 shows the deviation of a magnetic compass needle from true north. For example,

in Boston, the isogonic chart indicates a deviation of approximately 15.5º west. This implies that true south is actually 15.5º west of the indicated compass south. In this case, solar collectors oriented to an uncorrected south compass direction would actually be facing approximately 15.5º east of true south.

The deviation between compass indicated north/south and “true” north/south is called magnetic declination. It can be precisely determined for any location based on latitude and longitude using the calculator at the following Web site: http://www.ngdc.noaa.gov.

The deviation between a true north/south line and magnetic north/south line varies slightly over time. This variation is caused by the magnetic properties of magma flowing deep beneath the earth’s crust. Because of this, isogonic charts are typically dated. Fortunately the deviations over time are relatively minor and will have essentially insignificant impact on solar collector installation and subsequent performance.

7

TYPES OF SOLAR THERMAL SYSTEMS: Any device or combination of components intended to convert solar radiation into usable heat can be classified as a solar thermal system. Our discussion of such systems will be limited to those intended to heat buildings and/or domestic water.

In a broad context, solar thermal systems can be classified as either passive or active.

PASSIVE SOLAR THERMAL SYSTEMS:Solar thermal systems that collect solar radiation and deliver it to the heating load without need of fans or circulators are called passive systems. A building with suitable amounts of south-facing windows combined with internal thermal mass (concrete walls, floors or water-filled containers) is itself a passive solar thermal system. When properly designed, such a building can reduce the need for heating energy from conventional sources by 50% or more. Passive solar buildings in sunny climates can achieve even higher fuel savings, all without the need of fans or circulators.

There are many ways of constructing passive solar buildings. These include direct gain through windows, attached sunspaces and trombe walls. One of the simplest is a direct gain passive building, as illustrated in figure 9. Light from the low wintertime sun shines through south-facing windows. Much of the light is instantly

summer

sun

winter

sun

solar energy absorbed

roof overhang

shades windows

in summer

south-facing

windows

to room at night

Figure 9

Figure 8

8

converted to heat as it strikes the floor and other objects in the room. Some of this heat immediately raises the interior air temperature. The rest is absorbed by the concrete floor slab and other objects in the space. The absorbed heat is later released into the room as the interior air temperature cools. Properly proportioned roof overhangs shade the south-facing windows during summer to limit solar gains.

There are also passive solar thermal systems for heating domestic water. An example of one such system is shown in figure 10.

This system consists of an insulated storage tank located above a sloped solar collector. The tank may be located inside or outside. When warmed by incoming sunlight, water in the solar collector expands. Its reduced density compared to cooler water in the bottom of the storage tank creates a gentle circulation effect.

The warmer (lighter) water rises as the cooler (heavier) water descends. This is called “thermosiphoning,” and it conveys heat from the collector to the storage tank without need of a circulator. Thermosiphoning continues as long as water in the collector is warmer than water in the storage tank. As sunlight diminishes, the collector cools to a temperature below that of the storage tank, and the flow stops. As hot water is used in the building, cool water enters the storage tank to replace the exiting hot water. This type of passive water-heating collector must be drained if freezing weather is expected. It is used primarily in climates with minimal, if any, freezing conditions.

In the system shown, heated water from the solar storage tank is routed to the inlet of an electric water heater, where its temperature is increased to the desired setpoint (when necessary). A thermostatic mixing valve on the outlet of this water heater prevents high temperature water from reaching the building’s fixtures. High water temperatures are possible in almost any type of solar water heating system during prolonged sunny weather, especially if hot water demand is low.

ACTIVE SOLAR THERMAL SYSTEMS: Any system that uses a blower or circulator to move air or a liquid through the solar collector(s) is classified as an active solar thermal system. As with passive systems, there are countless variations in design for both space heating and domestic water heating. These variations all have strengths and limitations. Several will be discussed in later sections. However, before discussing systems,we’ll examine options for one of the most important components in such systems — solar collectors.

Nearly all liquid-based active systems use either a “flat plate collector” or “evacuated tube collector.”

electric DHW tank

cold water

hot water

anti-scald

tempering valve

pressure &

temperature

relief valve

electric

heating

element

solar

colle

ctor

insulated

storage

tank

heated space

drain pipe

(min. 1/4"/ft pitch)

cold

water

heated

water

warm water rises

N.O

.N.C.

cool water descends

insulated piping

air vent

open this

valve to

drain collector

N.O

.

close these

valves before

draining

collector

open to provide

non-solar

water heating

Figure 10

9

FLAT PLATE COLLECTORS:An example of a flat plate solar collector is shown in figure 11.

The principal component in this type of collector is the absorber plate, which is usually an assembly of copper sheet and copper tubing. The top surface of the absorber plate is coated with dark colored paint or electroplated “selective surface” coating that absorbs the vast majority of solar radiation striking it. The instant solar radiation strikes this surface it is converted to thermal energy (e.g., heat). The copper sheet acts as a wick to conduct this heat toward the copper tubing that is welded or otherwise bonded to the sheet. Heat moves across the copper sheet toward the tubes because the fluid flowing through the tubes is cooler than the absorber sheet. This fluid absorbs the heat and carries it out of the collector.

To minimize heat loss, the absorber plate is usually housed in an enclosure made of aluminum and capable of withstanding many years of exterior exposure. The sides and back of this enclosure are insulated with materials capable of withstanding temperatures in excess of 350ºF, which might occur if the collector is exposed to intense sunlight without fluid flow through its absorber plate.

The upper surface of the enclosure is usually tempered glass with a low iron oxide content. Tempered glass can withstand high thermal stress as well as potential impact from hailstones or other objects. Low iron oxide content glass minimizes absorption of solar radiation as it passes through on its way to the absorber plate.

aluminum housing

tempered, low-iron glass

copper sheet absorber plate(with selective surface coating)

copper tubing welded to copper sheet

high temperature resistant insulation

rear cover sheet

copper "headers"

tempered, low-iron glass

copper "headers"

aluminum housing

selective surface coatingon absorber plate

36" to 48" (typical)

84

" to

14

4"

(typic

al)

copper header connection

copper tubeswelded to copper sheet

Figure 11

10

EVACUATED TUBE COLLECTORS:Another type of active solar collector consists of several glass tubes, each of which has concentric inner and outer walls. The annular space between these glass tubes has been evacuated of air and thus acts like a Thermos® bottle. Convective heat transfer between the inner and outer glass tubes is essentially eliminated. A coated copper absorber strip with attached tubing is located within the inner glass tube, as shown in figure 12.

Most current-generation evacuated tubes have a specialized fluid sealed within the internal copper tubing. When heated, this fluid changes from liquid to vapor and rises toward the top of the tube. It then passes into a small copper capsule that fits tightly into a manifold assembly at the top of the collector. Heat conducts though this copper capsule into fluid circulating along the manifold. The fluid sealed within the evacuated tubes never contacts the fluid in the manifold. As heat is released from the fluid within the evacuated tube, it condenses back to a liquid and flows back to the bottom of the tube ready to repeat the cycle.

A roof-mounted array of evacuated tube collectors is shown in figure 13. The manifold can be seen at the top of the evacuated tubes.

SOLAR COLLECTORS FOR POOL HEATING:Pool heating is often one of the most economically viable forms of solar energy utiliza-tion (assuming it displaces what would otherwise be conventional fuels used to heat the pool).

Most solar pool-heating systems use an unglazed and uninsulated flat plate collector. This is acceptable because the absorber plate operates very close to — if not lower than — ambient air temperature. Under such conditions, the absorber plate loses very little, if any, heat due to convection, and thus does not need an enclosure to prevent heat loss.

The absorber plate is usually constructed of UV-stabilized polymers compatible with pool water chemistry. It consists of an upper and lower header with several polymer

insulated copper manifold

evacuated tube envelope

copper absorber strip

concentric copper tubing

selected surface coating

72"-96" (typical)

72

" to

84

" (t

ypic

al)

outer glass tubeinner glass tube

concentric copper heat pipe

copper absorber strip

evacuated annular space

Photo courtesy of Hi Valley Supply

Figure 12

Figure 13

11

tube/plate assemblies thermally fused in between, as illustrated in figure 14.

Pool-heating collectors have a very high wetted surface area to compensate for the lower thermal conductivity of the polymer material versus copper. They are also designed to accommodate substantially higher flow rates than would be used with enclosed flat plate or evacuated tube collectors. These collectors are often mounted on roofs at relatively low slope angle to optimize summertime solar gain. Pool-heating collectors are NOT suitable for domestic water-heating or space-heating applications.

SOLAR COLLECTOR PERFORMANCE: When designing active solar energy systems, it’s important to be able to predict the thermal performance of solar collectors over a wide range of operating conditions.

One method of expressing the thermal performance of a collector is a numerical value for thermal efficiency, which is the ratio of the instantaneous heat output from the collector divided by the rate solar radiation strikes the panel. It is similar to the thermal efficiency of a boiler

in that it states the desired output quantity (collected heat) as a percentage of the required input quantity (solar “fuel”).

The thermal efficiency of a collector changes whenever the fluid inlet temperature, the ambient air temperature or the intensity of solar radiation striking it varies. To account for these factors, the thermal efficiency of a solar collector is typically expressed graphically, as shown in figure 15.

Here, the collector’s thermal efficiency is plotted on the vertical axis as a function of a grouping of terms called the “inlet fluid parameter” on the horizontal axis.

Where:Ti= inlet fluid temperature to the collector (ºF)Ta = ambient air temperature surrounding the collector (ºF)I = solar radiation intensity striking the collector (Btu/hr/ft2)

The greater the value of the inlet fluid parameter, the more severe the conditions under which the collector operates, and the lower its thermal efficiency.

enla

rged c

ross

ecti

on

of

poly

mer

tube/sh

eet

upper polymer manifold

lower polymer manifold

36" to 48" (typical)

96

" to

14

4"

(typic

al)

Figure 14

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

p =Ti Ta( )I

Figure 15

12

For example, assume water at 160ºF is supplied to a flat plate collector having the efficiency line shown in figure 15. At the same time, the outdoor air temperature surrounding the collector is 20ºF, and the solar radiation striking the collector is 200 Btu/hr/sq. ft. (see figure 4 for examples of solar radiation intensity). The inlet fluid parameter under these conditions is:

Locating 0.7 on the horizontal axis of figure 15 and projecting up to the line and over to the vertical axis indicates the collector’s thermal efficiency is 0.16 (e.g., 16%). Hence, under these operating conditions, only 16% of the solar energy striking the collector is converted into useful heat output. This is certainly not very high, especially when compared to the efficiency of hydronic heat sources such as boilers. The low efficiency is due to the unfavorable operating conditions (e.g., forcing the collector to operate with a relatively high inlet fluid temperature during cold outdoor conditions).

For comparison, assume the same collector operates in a system where it receives water at 95ºF under the same outdoor air temperature and solar radiation conditions. The inlet fluid parameter is now:

Under these conditions, the collector’s thermal efficiency is 0.43 or 43%. The significant drop in the inlet fluid temperature results in much higher thermal efficiency. This demonstrates that collector efficiency is extremely dependent on inlet fluid temperature. For the best performance, the inlet fluid temperature to any solar collector should be kept as low as possible.

The slope and vertical axis intercept of a solar collector’s thermal efficiency line are established by testing. In the United States, the standard testing procedure is ASHRAE Standard 93-77 “Methods of Testing to Determine the Thermal Performance of Solar Collectors.” The results of such testing are often

published in technical literature for the solar collector. These performance indices are also used as inputs to software that simulates the thermal performance of solar energy systems. Examples of such simulations are given in later sections.

COMPARING SOLAR COLLECTORPERFORMANCE:Given the different construction of flat plate and evacuated tube solar collectors, it’s reasonable to ask which type is better. There is no simple answer to this question. The collector with the greatest heat collection potential depends strongly on the specific application in which the collector will be used. Beyond thermal performance, the designer must also weigh factors such as differences in roof area requirements, maintenance requirements, ability to shed snow and the type of freeze protection options available for each type of collector.

From the standpoint of thermal performance only, the collector with the best performance depends on the temperature required by the load the system supplies. This is demonstrated by comparing the three collector efficiency lines shown in figure 16.

This graph is based on a sampling of performance ratings for different types of collectors as determined by the SRCC (Solar Rating and Certification Corporation). It shows that the collector with the highest thermal efficiency depends on the value of the inlet fluid parameter, which itself depends on collector inlet fluid temperature, outdoor air temperature and solar radiation intensity.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1

Ti TaI

F ft 2 hr

Btu

Figure 16

13

If the load is a swimming pool where water temperature is at or just above ambient air temperature, an unglazed flat plate collector will provide the highest thermal efficiency. This is the result of two factors: First, the incoming solar radiation is not attenuated by passing through a glazing; secondly, there is very little if any heat loss from an absorber plate operating close to ambient air temperature.

However, as the load temperature increases, an unglazed collector rapidly loses efficiency relative to a glazed/insulated flat plate collector. At even higher inlet fluid temperatures, an evacuated tube collector, with its very low heat loss characteristics, retains higher thermal efficiency than a glazed flat plate collector.

The only accurate way to compare seasonal performance of flat plate versus evacuated tube collectors is through computer simulation based on a specified load in a specified climate.

Other issues differentiate flat plate and evacuated tube collectors.

• Flat plate collectors typically have a higher ratio of absorber plate area per square foot of collector enclosure compared to evacuated tube collectors. This means evacuated tube collectors usually require more roof area to accommodate a given amount of absorber plate surface.

• Because of their manifold design, most current-generation evacuated tube collectors must operate with an antifreeze solution and are not suitable for other types of systems.

• Evacuated tube collectors tend to be more expensive than flat plate collectors on a dollar per square foot of absorber plate area basis.

• Flat plate collectors cannot produce water temperatures as high as those possible with evacuated tube collectors. This may or may not be an issue, depending on intended application.

• Some flat plate collectors can be architecturally integrated into roofs to minimize their visible profile.

• Flat plate collectors sloped at 40º or more shed snow sooner than evacuated tube collectors mounted at the same angle. The low heat loss of evacuated tube collectors increases the time needed to warm snow to the point where it will slide from the tubes.

STAGNATION CONDITIONS:There are times when solar collectors will likely be exposed to bright sun conditions without any fluid flow. Such a situation could result from a control or circulator malfunction, the storage tank reaching its high temperature limit or a power outage. Under such conditions, the collector is said to be “stagnating” and can reach internal temperatures of 350ºF or more. Such temperatures can cause failure of PEX or PEX-AL-PEX tubing and thus rule out its use between the collector array and mechanical room in most active solar systems. Prolonged stagnation can also cause a chemical breakdown of glycol-based antifreeze solutions. Some active solar energy systems are equipped with “heat dump” subsystems that limit temperatures under stagnation conditions.

TYPES OF ACTIVE SOLAR THERMAL SYSTEMS:There are several ways to combine solar collectors with other hardware to build active solar energy systems. Designs differ with the intended use of collected heat as well as methods of freeze protection. This section discusses the basic system concepts used for domestic water heating and space heating. In some cases, both of these loads can be supplied from a single system.A simplified schematic for an active solar thermal system is shown in figure 17.

solar c

ollect

or array

(side view

for s

chem

atics)

heating

load

thermal storage tank

collector

circulator

check

valve

load

circulator

differential

temperature

controller

storage

temperature

sensor

collector

temperature

sensor

colle

ctor

RET

URN p

ipe

collector

SUPPLY

pipe

expansion

tank

pressure

gauge

pressure

relief valve

to top of tank

air vent

air vent

w/ shut off

valve

Figure 17

• Flat plate collectors typically have a higher ratio ofabsorber plate area per square foot of collector enclosurecompared to evacuated tube collectors. This means evacuated tube collectors usually require more roof area to accommodate a given amount of absorber plate surface.

• Because of their manifold design, most current-generation evacuated tube collectors must operate with an antifreeze solution and are not suitable for other typesof systems.

• Evacuated tube collectors tend to be more expensivethan flat plate collectors on a dollar per square foot ofabsorber plate area basis.

• Flat plate collectors cannot produce water temperatures as high as those possible with evacuated tube collectors.This may or may not be an issue, depending on intendedapplication.

• Some flat plate collectors can be architecturally integrated into roofs to minimize their visible profile.

• Flat plate collectors sloped at 40º or more shed snowsooner than evacuated tube collectors mounted at thesame angle. The low heat loss of evacuated tube collectors increases the time needed to warm snow tothe point where it will slide from the tubes.

14

The collector array (one or more collectors) is piped to a thermal storage tank. The collector circulator moves water from near the bottom of the storage tank up through the collector array and back to the tank. This circulator operates whenever the collector array is warmer than the storage tank. A check valve in the collector supply piping prevents reverse flow, which would otherwise occur when the collector temperature drops below the storage tank temperature. Another circulator is shown to move warm water from the top of the storage tank through the heating load as required.

Although simple in concept, this system as shown would seldom be suitable for a specific application. It doesn’t contain any method of freeze protection, nor does it provide a way to supply heat to the load when the water in the storage tank is too cool to be used by that load. Both of these issues are critical to proper system operation and are addressed through the further refinement and detailing to be discussed.

CONTROLLING THE SOLAR COLLECTION PROCESS:Most active solar energy collection systems are controlled by a differential temperature controller. This device monitors two temperature sensors. One is located within or very near the outlet of a solar collector. The other is mounted in contact with the metal wall of the storage tank, as shown in figure 17. The differential temperature controller constantly measures the temperature difference between these sensors. When the collector sensor temperature exceeds the storage tank temperature by a specific value (typically 3 to 10ºF) the controller turns on the collector circulator. When the collector temperature is very close to, equal to, or below the storage tank temperature, the controller turns off the collector circulator.

This control logic allows collection of solar energy whenever possible. On a given day, the differential temperature controller may turn the collector circulator on and off several times, depending on how the collector temperature is affected by cloud cover, wind or shading.

Some differential temperature controllers also operate the circulator at speeds proportional to the differential temperature between the collectors and storage tank. As this differential rises, the collector circulator speed increases, and vice versa. This technique reduces the electrical consumption of the circulator under partial sun conditions.As with any temperature sensor, it is vital that the sensor housing remain in tight contact with the surface it is measuring. The portion of the sensor not in contact with

the surface being measured should be protected by insulation to prevent readings from being affected by surrounding air.

FREEZE PROTECTION METHODS:Solar collectors containing water can be severely damage by a single night of sub-freezing temperatures. This can occur even in traditionally warm locations like Florida, Texas and Arizona. All active solar energy systems installed in the United States and Canada should employ some method of freeze protection.

Although manually draining the collector and any exposed piping when freezing conditions are imminent will prevent damage, this method relies on human intervention and is only suitable for climates where freezing conditions are extremely rare. All other locations should use a system designed for automatic and unattended freeze protection.

pressure

relief valve

expansion

tank

solar c

ollect

or array

heating

load


collector

circulatorinternal

heat

exchanger

load

circulator

air

separator

this circuit operates

with antifreeze solution

check

valve

valves

air vent

valve

Figure 18

15

One common method of freeze protection is to design the collector-to-storage circuit as a closed loop and operate it with a suitable antifreeze solution. This solution passes through the collector array and then through a heat exchanger that transfers the collected heat to water in the storage tank. The heat exchanger may be located within the storage tank as shown in figure 18, or outside the tank as shown in figure 19.

Systems with storage tanks having internal heat exchangers only require one collector circulator. Those with external heat exchangers require two circulators, and thus have slightly higher electrical power consumption.

Both types of heat exchangers should be generously sized to maximize system efficiency. The larger the heat exchanger, and the greater its effectiveness, the cooler the collector array can operate relative to the storage tank temperature. As previously discussed, the cooler the collector operates, the higher its efficiency.

CLOSED-LOOP DRAINBACKSYSTEMS:An alternative method of freeze protection is to drain all water from the collector array and exposed piping whenever the system is not collecting solar energy. This is called a drainback system. It relies on gravity along with properly pitched piping and collectors to quickly drain water whenever the collector circulator turns off. A schematic for a typical closed-loop drainback system is shown in figure 20.

In a drainback system, the collector circuit operates with water, and is initially filled to a predetermined level. That level is part way up the height of the drainback tank, as seen in figure 20. When the collector circulator is off, all piping above this water level, as well as the collector array, is filled with air, and thus not subject to damage when temperatures drop below freezing. All piping and components below the fill level are filled with water.

When the collector circulator turns on, water is pushed up the collector supply piping and into the collector

array. This water pushes air ahead of it. Eventually the rising water reaches the top of the collector array and continues flowing down the return piping toward the drainback tank. Again, air is pushed ahead of the water or entrained with the flow, and eventually returned to the drainback tank. This process causes a slight drop in the water level within the drainback tank as water replaces air in the collectors and piping.

This operation continues as long as the collector circulator is running. As soon as this circulator shuts off, air from the top of the drainback tank rises up the collector return piping and into the collector array as water returns to the drainback tank. The majority of the water in the collector array usually siphons backward and returns downward into the storage tank. Since the storage tank is filled with water, the level within the drainback tank rises back to its original level.

pressure

relief valve

solar c

ollect

or array


collector

circulator

load

circulator

storage

circulator

(w/ check)

heat

exchanger

expansion

tank

valves

heating

load

air

separator

air vent

w/ shut off

valve

Figure 19

16

The collector circuit is a closed loop, as is the remainder of the hydronic system shown. The initial charge of water and air are thus sealed within the system and circulated over and over through the collectors and piping, as well as other parts of the system. The air within the drainback tank can be at a slight positive pressure relative to the atmosphere to ensure the remainder of the system operates under sufficient pressure. In some systems, the air space in the drainback tank can be sized to serve as the expansion volume for the system and thus eliminate the need for a traditional expansion tank.

No air vents are placed at the top of the collector array in a drainback system. No automatic make-up water system or air-separating device can remain active in this type of system past an initial filling condition. Doing so would eventually replace the air in the system with make-up water and thus “water log” the system. This would prevent drainage and eventually cause severe damage due to freezing.

It is critically important that any piping or other components located outside heated space are pitched a minimum of 1/4 inch per foot to allow efficient drainage. The collector array may also have to be pitched slightly to ensure complete drainage (verify with collector manufacturer).

The drainback system concept shown in figure 20 eliminates the need for heat exchangers and antifreeze. This allows the collectors to operate at the lowest possible temperature and thus optimizes their efficiency.

However, drainback systems typically require more electrical energy to maintain flow than do closed-loop antifreeze-based systems. This is a result of the “lift” requirement to push water up into the collector array and piping each time the circulator starts. In some systems, two circulators in series may be needed to provide the needed lift.

The collector return piping should be sized to ensure a flow velocity no lower than two feet per second. This ensures that air bubbles will be entrained and returned to the drainback tank when the collector circuit begins operation. It also allows a siphon effect to be established over the top of the collector array, which reduces the lift head present when the collector circulator first starts. When this is the case, it’s common to operate the two series-connected collector circulators until a siphon is established over the top of the collector array and the return piping is completely filled with water. This process,

which may take several minutes, eliminates the initial lift head and makes the circuit operate as a fluid-filled closed loop. Once the siphon is established, only one collector circulator is needed to maintain flow. The other (downstream) circulator can be turned off to reduce electrical consumption.

WHICH METHOD OF FREEZE PROTECTION IS BEST?Just like the choice between flat plate and evacuated tube collectors, there is no simple answer to this question. Listing the strength and limitations of each method can help steer the designer toward an appropriate choice for a given application.

Strengths of closed-loop antifreeze systems:• Pitched piping is not required• Low wattage collector circulators can often be used• No drainback tank is required

pressure

relief valve

heating

load


collector

circulator(s)load

circulator

solar c

ollect

or array

lift head

drainback

tank

air space

level

indicator

air vent

w/ service

valve

Figure 20

17

Limitations of closed-loop antifreeze systems:• Requires the added expense of heat exchangers and

antifreeze, as well as additional pressure relief valve,expansion tank, fill/purge valve

• Forces collectors to operate slightly warmer thanstorage tank and thus at slightly reduced efficiency

• Antifreeze solutions are subject to chemical breakdown from prolonged stagnation conditions• Chemical Ph of antifreeze solutions should be checked

annually and fluid replacement is necessary when Ph ofsolution can no longer be maintained

Strengths of closed-loop drainback systems:• Slightly higher efficiency by operating collectors at

lowest possible temperature• Does not require antifreeze or other components

associated with the use of antifreeze• Drainback tank may serve as expansion tank for

remainder of system

Limitations of closed-loop drainback systems:• Piping or collectors that are not properly pitched

will result in costly hard freeze• Higher pumping power required due to lift head• Must ensure proper f lu id leve l in system for dra inback operation• Requires drainback tank placed as high as possible

within the system

As you can see, each approach has its advantages and disadvantages. The choice between the two tends to become easier in the context of specific applications.

ACTIVE SOLAR DOMESTIC WATER HEATING:Some of the most economically viable active solar energy systems are those used for domestic water heating. They can be scaled for use in a single-family residence, or much larger for use in hotels, laundromats, carwashes or other commercial/industrial buildings with substantial domestic water-heating requirement. This section exams many of the options currently available.

SINGLE TANK SYSTEMS:A schematic for a typical solar domestic water-heating system based on a single tank with internal heat exchanger is shown in figure 21.

This arrangement is called a single-tank system. An internal heat exchanger near the bottom of the tank provides solar heating (or preheating) of the domestic water in the tank. The upper portion of the tank is maintained at a set temperature by a thermostatically controlled electric heating element.

The warmest water stays near to the top of the tank due to its lower density. This helps preserve cooler water at the bottom of the tank to maximize the performance of the heat exchanger and keep collector temperatures as low as possible. Cold water entering the tank is directed near the bottom by the internal dip tube. Temperature stratification also ensures the hottest water is withdrawn from the top of the tank.

An anti-scald tempering valve rated to handle incoming water temperatures of at least 210ºF ensures that scalding hot water is not delivered to faucets or other fixtures. This is a crucially important component in any solar domestic water-heating system, which can easily produce scalding hot water during prolonged sunny weather, especially when demand is low.

solar c

ollect

or array

solar storage tank

with internal heat exchanger

and electric heating element

valves

air

tank

cold water

hot water

anti-scald

relief

valve

electric

heating

element

relief

valve

air vent

valve

Figure 21

18

The solar collector circuit includes circulator, fill/purging valves, pressure relief valve, pressure gauge, expansion tank, air separator, check valves, and a high-point float-type air vent with shutoff valve. Many of these components provide the same function in the solar collection circuit as they would in a conventional hydronic system. As previously mentioned, the check valve prevents reverse flow when the collectors cool below the temperature of the storage tank. If such flow were allowed to occur, much of the heat within the tank would be dissipated through the collector array at night or under low sun conditions. The shutoff valve connecting the high-point float vent to the top of the collector array should be closed as soon as the collector loop has been deareated. This protects the vent mechanism against stagnation temperatures. The shutoff valve can be reopened if the collector loop is ever drained and refilled.

Another variation of a single-tank system is shown in figure 22. In this case, an external heat exchanger is used along with an additional circulator between that heat exchanger and the domestic water tank. This allows a properly sized existing domestic water storage tank to be retrofitted for solar heating. The storage tank should provide a minimum of 1 gallon of storage volume per square foot of collector area. Tanks that provide 1.5 to 2 gallons of storage per square foot of collector area will increase the solar energy collected on an annual basis. Be sure that any existing hot water tank retrofit in this manner is equipped with an anti-scald-rated thermostatic mixing valve to protect against possible high-temperature water produced during prolonged periods of sunny weather.

Single-tank systems have the advantage of a small footprint and reduced cost. However, they typically do

not collect as much solar energy on an annual basis as do systems that separate the solar storage tank from the auxiliary heating means (in this case, the electric heating element).

TWO-TANK SYSTEMS:Another variation on the closed-loop antifreeze-based solar water-heating system is shown in figure 23. This is called a two-tank system, and it’s typical for residential systems where a conventional water heater is already installed.

In a two-tank system, cold water first flows into the solar storage tank. During sunny weather this tank may provide all the heating necessary. However, during less favorable conditions the water may only be preheated. An example of the latter is 45ºF cold water warmed to 85ºF as it is drawn out of the solar storage tank. The preheated water then flows to the inlet port of a conventional tank-type water heater where heat from conventional fuel or electricity raises it to the required delivery temperature.

It’s important to remember that, even when water leaving the solar storage tank has only been preheated, the process can represent a substantial reduction in conventional energy use. For example, water preheated from 50ºF to 90ºF represents about (40/70) or 57% of the energy input needed to

differential

temperature

controller

existing DHW tank

heat

exchanger

valves

pressure

relief

valve

cold water

hot water

anti-scald

tempering valve

pressure &

temperature

relief

valve

electric

heating

element

expansion tank

air vent

valve

solar c

ollect

or array

Figure 22

19

raise that water to a final temperature of 120ºF. It takes just as much heat to raise a gallon of water from 45 to 46ºF as it does to raise that water from 119 to 120ºF. Energy input at low temperatures is ideally suited to the solar portion of the system since low operating temperatures significantly improve collector efficiency.

Two-tank systems typically provide greater solar energy collection on an annual basis relative to single-tank systems. This is due to increased storage mass and the separation of conventional energy input from the solar storage tank. On the other hand, poorly insulated storage tanks can all but erase this potential performance

advantage by leaking heat away from the water and into the surrounding air. In the absence of specific code requirements, all storage tanks should be insulated to a minimum of R12 (ºF•hr•ft2/Btu), and all connecting piping should be insulated to at least R3 (ºF•hr•ft2/Btu).

A set of three ball valves is shown on the piping between the two tanks in figure 23. These allow the solar storage tank to be completely isolated from the conventional tank, and the latter to act as the sole water-heating device should the solar system ever be shut down for service. Also note that both tanks are equipped with pressure and temperature relief valves.

solar c

ollect

or array

solar storage tank


conventional

tank-type water heater

anti-scald

tempering valve

pressure &

temperature

relief

valve

electric

heating

elements

(shown)

valves

pressure

relief

valve

N.O.

N.O. N.C.

expansion

tank

air vent

valve

Figure 23

20

BYPASS SYSTEMS:Still another method of constructing a solar water-heating system is shown in figure 24. This approach is especially relevant when modulating “tankless” water heaters are used for auxiliary domestic water heating.

In a bypass system, the temperature of the water leaving the solar storage tank is constantly measured. If the water is hot enough to go directly to the faucets, the motorized diverter valve routes it to the anti-scald tempering valve. If the water requires additional heating, the diverter valve routes it to the tankless water heater. From there it again passes to the anti-scald tempering valve before heading for the faucets.

Isolating ball valves are shown that allow the tankless water heater to function as the sole domestic water-heating device if the solar subsystem is turned off for servicing.

This approach has several unique benefits. First, it does not add heat derived from conventional energy to the solar storage tank, and thus allows the collectors to operate at the lowest possible temperature for high efficiency. Secondly, it does not have the exposed surface area of a second water storage tank. This, combined with the fact that heated water does not pass through the tankless heater unless it is operating, significantly reduces standby heat loss. Finally, this design significantly reduces the mechanical room “footprint” relative to a two-tank system.

solar c

ollect

or array

solar storage tank


cold water

hot water

tankless

(modulating)

water heater

motorized

diverting

valve

N.O.

N.O.

N.C.

temperature

setpoint controller

anti-scald

tempering valve

N.O.

pressure

relief valve

expansion

tank

collector

circulator air

separator

check

valve

valves

air vent

valve

Figure 24

21

SOLAR CIRCULATION STATIONS:Many solar domestic water-heating systems use the same or similar components within the solar collection circuit. To speed installation, some manufacturers offer preassembled “solar circulation stations” that combine the functionality of several independent components into a single unit. These stations speed installation and ensure all hardware is correctly sized and located. The concept of a solar circulation station is shown in figure 25.

ACTIVE SOLAR SPACE HEATING SYSTEMS:Active solar space heating is possible, both as a singular application or in combination with other loads such as domestic water heating and pool heating. Carefully designed systems can provide years of reliable operation.

Given that solar availability is lowest when space-heating loads are highest, it’s unrealistic and uneconomical to attempt to supply 100% of a space-heating energy requirement through an active solar energy system. Active solar space-heating systems are almost always supplemented with an auxiliary heat source. In many cases, the transition from solar-derived heat to heat from conventional fuel is fully automatic and never noticed by the building occupants. In other systems, the auxiliary heat source may require manual start-up. An example of the latter is a wood stove.

There are three principles that need to be observed when designing solar space-heating systems.

solar collector array

site

assembled

components

solar c

ollect

or array

solar

circulation

station

air vent

w/ shut off

valve

air vent

w/ shut off

valve

Figure 25

22

Principle #1: Space-heating distribution systems that operate with low-temperature water will result in greater solar energy utilization.

Principle #2: Conventional energy sources (oil, gas and electricity) should only be “invoked” when instantaneously needed by the load. These fuels should not be converted to heat prior to being needed and stored in thermal form.

Principle #3: The collector array and all exposed piping components must be protected against freezing during non-operational periods.

SYSTEM CONFIGURATIONS:Hydronic-based solar subsystems can supply heat to either hydronic or forced-air space heating delivery systems.

Low-temperature hydronic floor heating is an ideal heat emitter to combine with active solar collectors. Parameters such as tube spacing, underside insulation and floor coverings should all be selected to allow the distribution system to operate at the lowest possible temperature.

An example of an antifreeze-based solar subsystem supplying a radiant panel distribution system in combination with a conventional gas-fired boiler is shown in figure 26.

The solar collection subsystem uses a stainless steel flat plate heat exchanger between the water in the storage tank and the antifreeze solution in the collector circuit. Because the latter is a closed loop, it’s equipped with an expansion tank, pressure relief valve and fill/purging valves. The check valve prevents reverse flow of collector fluid when the collectors are cooler than the storage tank. A differential temperature controller constantly monitors the temperatures of the collectors and storage tank. Whenever the collector temperature exceeds the storage temperature by a set amount, the circulators on both sides of the heat exchanger are turned on. An optional automatic fluid feeder is shown. This device constantly monitors pressure in the collector circuit, and adds premixed glycol solution when necessary to compensate for minor drops in pressure. It is usually only needed in larger systems.

VENT


tank circulator (w/ check)

boiler circulator

(w/ check)

closely

spaced

tees

outdoor

temp.

sensor

3-way

motorized

mixing valve

low temperature

radiant panel circuits

outdoor

reset

controller

outdoor

temperature

sensor

differential

temperature

controller

solar c

ollect

or array

heat

exchanger

valves

expansion

tank

pressure

relief

valve

collector

circulator

air vent

w/ shut off

valve

(optional)

Figure 26

23

An outdoor reset controller monitors the temperature at the top of the solar storage tank and constantly calculates the water temperature needed at the supply side of the distribution system. Upon a call for space heating, this controller determines if the storage tank temperature is at or above the currently required supply temperature for the distribution system. If it is, the tank circulator is turned on and water from the tank passes through the air separator and on to the closely spaced tees. These tees are the interface to a 3-way motorized mixing valve that supplies the distribution system. This mixing valve ensures that water from the storage tank,

which may be significantly hotter than required by the floor circuits, is not sent directly to them without being blended to the required temperature. The mixing valve also operates on outdoor reset control. When there is a call for heat and the storage tank is below the minimum usable temperature of the distribution system, the boiler and boiler circulator are turned on. The storage tank circulator remains off. The 3-way motorized mixing valve allows the low-temperature distribution system to operate at the necessary temperature, while also protecting the conventional boiler from sustained flue gas condensation.


tank

circulator

(w/ check)

collector

circulator(s)

boile

r circula

tor

(w/ c

heck)

solar c

ollect

or array

lift head

drainback

tank

air space

indicator

outdoor

reset

controller

outdoor

temperature

sensor

Collectors and all exposed

piping must pitch minimum

1/4 inch per foot for

proper drainage.

air riser tube

outdoor

temp.

sensor

3-way

motorized

Install drainback tank so static water

pressure

relief

Figure 27

24

The mixing valve controller must “ignore” the boiler inlet temperature sensor when heat is supplied from the solar storage tank. This sensor is not required if a condensing boiler is used as the auxiliary heat source. However, the 3-way motorized mixing valve should still be installed to protect the distribution system against potentially high storage tank temperatures.

Notice that water heated by the boiler does not circulate through the storage tank. This allows residual heat (e.g., heat at temperatures below the minimum usable temperature of the distribution system) to slowly transfer from the tank into the surrounding space. The cooler the storage tank, the sooner the solar collection process can begin when sunshine returns. When the storage tank warms back above the minimal usable temperature of the distribution system, the storage tank automatically becomes the heat source for the system.

A similar system using drainback freeze protection and a modulating/condensing boiler is shown in figure 27.

The solar collection subsystem does not use a heat exchanger or antifreeze. This allows the collectors to operate at a slightly low water temperature and hence slightly higher efficiency relative to the antifreeze-based system.

The drainback tank should be placed as high as possible within the building to minimize lift head and minimize drainback volume. The fill level within this tank should be at least 5 feet higher than other water-filled components in the system to ensure a minimal static pressure at these components even with no positive air pressure in the drainback tank. Pressure within the system can be further increased by adding air to the drainback tank using a hand pump or compressor. Be sure system pressure is high enough to satisfy any pressure safety switches in the boiler.

The dimensions of the drainback tank must allow it to accept the drainback volume from the collector array and exposed piping. In many cases, the dimensions of this tank can also be selected so it can serve as the expansion volume for the system. This eliminates the need for a conventional expansion tank.

As is the case with any hydronic system, there will be dissolved air in the system water at start-up. As the water’s temperature rises, some of this air will come out of solution. The goal is to route this air to the upper portion of the system (collectors and drainback tank) rather than release it from the system. If the storage tank is capable of trapping air bubbles above the collector return piping connection, it should be equipped with a small diameter air riser line, as shown in figure 27. This allows air at the top of the tank to rise back to the drainback tank, while at the same time allowing the majority of water flow from the collector array to enter the storage tank horizontally to preserve thermal stratification.

Float-type air vents should be installed at intermediate high points in the system to allow escape of trapped air. An example is the vent at the top of the boiler in figure 27.

Drainback systems should NOT have automatic make-up water assemblies. Installing such an assembly in combination with an automatic venting device would eventually replace the air in the system with water. Although this is desirable in conventional hydronic systems, in this system it will lead to a “waterlogged” drainback tank that prevents the system from draining. A costly hard freeze is certain to follow.

The water level in the drainback system should be periodically monitored when the collector circulator is off. Small quantities of water may have to be added to the system, especially after initial start-up, to replace the volume of any air ejected through high point vents.

25

ACTIVE SOLAR SUPPLYING FORCED-AIR SPACE HEATING:Although the majority of North American homes are heated by forced-air furnaces or heat pumps, they can still be adapted to hydronic-based solar heating. An example of such a system is shown in figure 28.

This system uses an antifreeze-based solar collection subsystem to heat the thermal storage tank. Upon a demand for heat, a setpoint temperature control determines if the water at the top of the storage tank is warm enough to supply space heating through the duct coil. If it is, a circulator moves tank water through the duct

coil and operates the furnace blower. The 3-way mixing valve protects the coil against excessively hot water from the solar storage tank. When the water temperature in the storage tank can no longer provide acceptable comfort, the setpoint controller allows the furnace burner to operate, and the storage tank circulator is turned off.

This is a relatively simple system and easily adapted to most existing furnace or forced-air heat pump installations. The duct coil should be selected to operate at the lowest possible water temperature to maximize solar utilization while also providing acceptable comfort in the heated space.

VENT

expansion

tank


heat

exchanger

valves

differential

controller

setpoint

controller

relief

valve

check

valve

air vent

air

separator

air vent

valve

3-way mixing valve

solar c

ollect

or array

Figure 28

26

COMBINED SOLAR SPACE & DOMESTICWATER HEATING:Many buildings with space-heating requirements also need domestic hot water. This is especially true of residential buildings. When a solar space-heating system is planned, it usually makes sense to extend the capabilities of that system to supply domestic water heating. In many situations, the auxiliary boiler that backs up the space-heating requirements can also supply auxiliary energy to the domestic water-heating load when necessary.

There are many hardware possibilities for combined solar space and domestic water heating. They vary on the solar collection side (i.e., antifreeze-based freeze protection versus drainback). They also vary based on available storage tank options, as well as the type of backup heat source used. This section discusses two state-of-the-art scenarios.

An example of one modern approach to solar space and domestic water heating is shown in figure 29a. A unique feature of this system is its dual coil storage tank, which contains domestic hot water and can be heated by the solar collection subsystem as well as the boiler.

Solar heat input is via a standard antifreeze-based closed-loop collector circuit. The lower coil heat exchanger is sized proportional to the collector array area. Since solar space heating typically requires more collector area than does solar domestic water heating, this coil may be substantially larger than the coils in tanks used only for domestic water heating.

The hottest domestic water is drawn from the top of the tank and passes through a 3-way anti-scald mixing valve to guard against excessively high water temperature at the faucets. The temperature at the top of the tank is constantly monitored. If it falls below a minimum

expansion

tank

DHW

VENT

ON

ON

Figure 29a

27

setpoint, the boiler and its circulator are operated along with the tank circulator. Hot water from the boiler mixes with water returning from the upper coil, and the combined flow enters the hydraulic separation chamber in the HydroLink. This chamber minimizes interaction between the two circulators. A portion of the heated water then passes back to the upper tank coil to boost DHW temperature. The remaining portion of the heated water flows back to the boiler. This mode of operation is shown in figure 29a. Temperature stratification within the tank minimizes heating of the lower portion of the tank to ensure solar collection begins at the earliest opportunity.

The upper coil can also extract heat from the tank’s water for use in space heating. With the boiler and its circulator off, the tank circulator moves hot water from the upper coil into the HydroLink. It is then distributed to the active space-heating circuits. Both space-heating circuits include motorized 3-way mixing valves to

protect against high water temperatures reaching low-temperature heat emitters. These valves should be operated by outdoor reset controllers to ensure the distribution circuits operate at the lowest possible temperature commensurate with the building heating load. This mode of operation is shown in figure 29b. Controls would be configured to stop space heating from the upper coil in the event the domestic hot water temperature at the top of the tank dropped to a minimum acceptable value.

Another possible operating mode is for the boiler to supply space heating, as shown in figure 29c. In this mode, the tank circulator is off. The boiler operates on its own internal reset controller to produce a supply water temperature equal to or just slightly above the highest required space-heating supply temperature. The space-heating subsystems draw from the HydroLink as in a standard hydronic system.

expansion

tank

DHW

VENT

Figure 29b

28

expansion

tank

DHW

VENT


tank circulator

(w/ check)

VENT

outdoor

reset

controller

boile

r circula

tor

(w/ c

heck)

indirect water heater

3-way

motorized

mixing valve

hydro

separator

differential

temperature

controller

heat

exchanger

valves

expansion

tank

pressure

relief

valve

collector

circulator

air vent

w/ shut off

valve

solar c

ollect

or array

Figure 29c

Figure 30

29

Another possible system design is shown in figure 30. This system uses a standard indirect water heater. A hydro separator hydraulically isolates the storage tank and boiler circulators from the circulators used for space heating and domestic water heating. It also serves as the central air and dirt separating device in the system.

Transition from solar-supplied heating to boiler-supplied heating is managed by the outdoor reset controller monitoring the solar storage tank temperature. This controller, or another controller, responds upon a call for domestic water heating to verify if the solar tank is sufficiently warm to supply the indirect water heater. If it is not, the boiler is fired to supply the indirect water heater. Space-heating circuits are temporarily turned off during this operation.

Again, the 3-way motorized mixing valve on the space-heating distribution system protects the low-temperature radiant panel circuits from potentially hot water supplied from the solar storage tank.

ACTIVE SOLAR SYSTEM INSTALLATION:The performance and longevity of any active solar energy system depends greatly on proper siting of the collector array. Good performance obviously demands absolute minimal shading of the collectors. A proper assessment of every potential site is highly recommended, especially if there are any indications of shading.

Although it’s possible to calculate the exact solar altitude and azimuth angles for any location on any day, using this information to assess the potential shading effects of nearby buildings, trees, hills or other objects is difficult. A

much simpler approach is the use of a tool called a solar pathfinder, as shown in figure 31. This simple device is placed at the location where shading is to be evaluated. After being leveled and properly oriented using the internal compass, its clear hemispherical dome projects the reflections of nearby objects onto a special chart that indicates the approximate times and months when that location is shaded.

Because solar intensity varies during the day, morning and late afternoon shading is not as critical as mid-day shading. As a rule, no portion of the collector array should be shaded between 9:00 AM and 3:00 PM (standard time).

The long-term reliability of an active solar system also depends on structurally sound collector mounting. Roof-, wall- and ground-mounted collector arrays are possible. Examples are shown in figure 32 and 33.

Image courtesy of SolarSkies, Inc.

Photo courtesy of SolarSkies, Inc.

Photo courtesy of Hot Water Products, Inc.

Figure 31

Figure 32

Figure 33

30

Modern solar collectors are tested for survival under extreme wind conditions as well as the impact of large hailstones. Most are able to withstand such punishing weather conditions for decades. However, inadequate mounting hardware could fail and lead to major structural damage. All roof-mounted collectors should have bracket systems that connect directly to structural framing using stainless steel fasteners and proper sealants for roof penetrations. Ground-mounted collector supports should be designed by an engineer in accordance with local wind loading conditions. Verify that all mounting hardware complies with local code requirements.

All piping between the collector array and internal mechanical room should be properly insulated to a minimum of R3 (ºF•hr•ft2/Btu), and protected against the weather where exposed. The piping must also be properly supported and pitched for drainage. In drainback systems, all piping exposed to freezing must be pitched to drain a minimum of 1/4 inch per foot of horizontal travel.

The equipment in the mechanical room should be neatly organized to minimize space requirements and provide easy access for service. When large storage tanks are planned into a system, provisions must be made for proper support as well as sufficient openings to get the tank into or out of the mechanical room. In some cases, multiple smaller tanks may be required to meet a specific storage requirement due to limited access.

COLLECTOR MOUNTING ANGLES:In the Northern Hemisphere, the ideal collector array azimuth angle is 180º (e.g., the collector array faces directly polar south). This orientation maximizes total clear day solar radiation striking the array. However, existing building surfaces may not provide this orientation. Fortunately, the annual total solar energy captured by a collector array is not highly sensitive to the array’s azimuth angle. Variations of 30º east or west of polar south typically only reduce annual solar energy collected by about 2.5%. The ideal slope angle of a solar collector depends on latitude as well as the intended function of the system.

For solar domestic water heating, the ideal slope angle is equal to local latitude. However, variations of +/- 10º on this angle will have minimal impact on the annual total solar energy collected. Thus, it often makes sense to mount collectors parallel to existing roofs where the slope of the roof is within +/-10º of local latitude, and forego the need for bracketing that would only make minor adjustments to the collector slope. In climates with snow, a minimum tilt angle of 40º is suggested to encourage rapid shedding of snow when the sun reappears.

In the case of solar space heating, somewhat steeper collector angles favor solar collection during late fall, winter, and early spring. Slope angles equal to local latitude plus 10º to 20º are appropriate for such systems. These relatively steep slopes actually reduce summertime solar collection and help prevent overheating from the larger collector arrays often used for space-heating applications. Even with this performance penalty, these larger arrays often provide a very high percentage of the domestic water-heating energy needed during warmer weather.

Figure 34 shows a collector array that supplies both space and domestic water heating. The collectors are sloped 60º in a location at 44º north latitude. In this project, the roof trusses were specially constructed to provide this collector slope while still mounting the collectors parallel to the roof surface.

ACTIVE SOLAR SYSTEM PERFORMANCE ESTIMATES:Given the unlimited combinations of collector area, mounting angles, storage tank options, water temperature requirements and many other factors, it’s essential to have a tool for evaluating the technical performance of proposed active solar energy systems. Given the extent of options and complex nature of solar energy availability, specialized software that simulates the performance of user-defined systems in a specific geographic location is the tool of choice. Several such software tools are currently available. Three of the most common are:

1. F-Chart: originally developed at the University of Wisconsin as a manual calculation procedure, the F-Chart method has been used for technical and economic analysis of active solar space- and domestic water-heating systems for over three decades. The current version of F-Chart software is available from www.fchart.com.

Figure 34

31

2. Tsol: Developed and primarily used in Europe, Tsol is simulation software for active solar thermal systems. It is available in both “express” and “professional” versions from http://www.valentin.de/.

3. RET Screen: Developed by Natural Resources Canada, RETScreen is powerful simulation software that can be used to study the technical and economic feasibility of active solar energy systems, as well as several other types of renewable energy technologies. This software is available as a free download from www.RETScreen.net.

The performance predictions presented in this section were derived using the latest version of F-chart software.

SOLAR HEATING FRACTION: One way of expressing the thermal performance of an active solar energy system is by stating the percentage of the load met by solar energy on a month-by-month basis. These monthly totals can also be combined to yield the annual solar fraction. The solar heating fraction is sometimes expressed as a decimal percentage (e.g., 0.15 = 15%).

SIMULATED PERFORMANCE OF SOLARDOMESTIC WATER-HEATING SYSTEMS:The table in figure 35 lists the annual solar fraction for various domestic water-heating loads in three different U.S. cities (Boston, MA; Milwaukee, WI; and Las Vegas, NV). In all cases, the following system assumptions were made:

Flat plate collector efficiency line intercept (FRta) = 0.76 Flat plate collector efficiency line slope (FRul) = 0.825Storage tank volume = collector area (ft2) x 1.5 (gallon/ft2)Closed-loop antifreeze system with heat exchanger effectiveness = 0.50Collector azimuth = 0º (e.g., collectors face directly south)Collector slope = approximately equal to local latitudeCollector flow rate = 11 lb/hr/ft2 (or 0.02 gpm/ft2) of collector areaSetpoint temperature for domestic hot water = 120ºFCold water temperature = typical of location

Annual solar fractions are given for four daily hot water loads (left column) and three solar collector area/storage tank volume scenarios (top row).

[As would be expected, the larger collector arrays and correspondingly larger storage tanks yield higher solar heating fractions in all locations. In looking at these results, one might assume the best system is the one supplying the highest percentage of the load. From a pure energy conservation standpoint, this may be true. However, the economic viability of the system is a different matter. Systems that supply very high solar heating fractions may not provide returns on investment as high as systems supplying lesser amounts of the load. The only way to know for sure is through detailed economic analysis of competing system options. Most solar system simulation software can also perform an economic analysis of the system.

BOSTON 40 ft2/60 gal. 80 ft2/120 gal. 120 ft2/180 gal.40 gal/day 72% 91% 96%60 gal/day 57% 85% 92%80 gal/day 48% 77% 89%100 gal/day 41% 69% 84%

MILWAUKEE 40 ft2/60 gal. 80 ft2/120 gal. 120 ft2/180 gal.40 gal/day 67% 88% 94%60 gal/day 54% 82% 90%80 gal/day 45% 74% 86%100 gal/day 38% 65% 81%

LAS VEGAS 40 ft2/60 gal. 80 ft2/120 gal. 120 ft2/180 gal.40 gal/day 94% 99% 100%60 gal/day 88% 98% 100%80 gal/day 77% 96% 99%100 gal/day 69% 94% 98%

Figure 35

32

SIMULATED PERFORMANCE OF COMBINED SOLARSPACE AND DOMESTIC WATER-HEATING SYSTEMS:Figure 36 shows the monthly solar heating fraction for the energy required to heat a house with a design heat loss of 50,000 Btu/hr located in either Syracuse, NY, or Colorado Springs, CO. In each case, the system also supplies heat to a 60 gallons per day domestic hot water load having a setpoint temperature of 120ºF.

The collector array for the system is that shown in figure 34. The six flat plate collectors have a total gross area of 112 square feet and face directly south at a slope of 60º. The storage tank has a volume of 300 gallons and is equipped with an upper coil heat exchanger for domestic water heating. Space heating is supplied through low-temperature heated floors.

Not surprisingly, the monthly solar heating fractions are rather low in winter given the relatively cold climates. However, it’s clear the system in Colorado Springs does significantly better at supplying winter heat compared to the same system in the much cloudier Syracuse, NY, location.

In both locations, solar fractions rise significantly during spring and fall. This results from increased solar energy availability as well as reduced heating load. As the space-heating load goes away during summer, both systems are able to supply very high percentages of the domestic water-heating load. During July and August, each system is estimated to supply 99-100% of the domestic water-heating load. Keep in mind that the collector slope of 60º favors winter sun angles. However, the relatively large collector area more than compensates for the losses due to the steep collector slope.

SOLAR PRODUCT CERTIFICATIONS:Maintaining the quality of solar energy products and system installations is vital to the long-term success of the solar energy industry. To this end, the Solar Rating and Certification Corporation (SRCC) was formed in 1980 as a non-profit organization to provide independent testing, rating and certification of active solar collectors and solar domestic water-heating systems.

The SRCC has developed and maintains two standards for testing and rating of solar hardware:

• Standard OG-100 “Operating Guidelines for Certifying Solar Collectors”

• Standard OG –300 “Operating Guidelines and Minimum Standards for Certifying Solar Water Heating Systems”

These guidelines are widely accepted across the United States as the basis for qualifying collectors and domestic water-heating systems for state and national tax credits, as well as for other organizations offering financial incentives for solar system installation.

Standard OG-100 requires that collectors undergo stringent testing for both thermal performance and durability. Collectors are tested for thermal output under a range of solar intensity and ambient temperature conditions. Their ability to withstand stagnation, severe weather and thermal stock are also tested.

Standard OG-300 combines the physical testing of collectors with a quality assurance review of all major components in a solar water-heating system proposed for sale by a manufacturer. The standard also provides simulated performance estimates for that system in specific geographic locations.

Additional information on the SRCC can be obtained from their Web site, www.solar-rating.org.

SUMMARY: We’ve discussed the fundamentals of active solar energy systems. As with hydronic heating, there are many specialized sub-topics within this area of technology. Future releases of idronics will address these subjects in more detail.

The use of solar energy in North America will increase with each passing year. Rapid increases in the cost of conventional fuel will accelerate the pace of this expansion. Knowing how to size and configure active solar heating systems is an important skill for hydronic heating professionals that expect to serve the growing demand for active solar space-heating and domestic water-heating systems.

1 2 3 4 5 6 7 8 9 10 11 12

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Predic

ted s

ola

r f

racti

on o

f to

tal space

heati

ng a

nd D

HW

load (

decim

al %

)

(based o

n F

-chart

sim

ula

tion s

oft

ware)

Month

Colorado Springs, CO ( ) annual solar fraction = 32.1%

Syracuse, NY ( ) annual solar fraction = 23%

Figure 36

33

APPENDIX 1:Volume and surface area reference information:

This appendix provides formulas and data for calculating the volume and surface areas of cylindrical tanks as well as the volume of tubing used in solar / hydronic systems.

Tank volume formula: Formula 1 can be used to calculate the volume of a cylindrical storage tank of known diameter and height:

Formula 1:

Where:Vtank = volume of tank (gallons)D = diameter of tank (inches)H = height of tank (inches)

Formula 2 can be used to calculate the volume of liquid of known height (h) with a vertically-oriented cylindrical storage tank of known diameter and height:

Formula 2:

Where:Vfluid = volume of fluid in tank (gallons)D = diameter of tank (inches)h = height of fluid in tank (inches)

Tank surface area formula:Formula 3 can be used to calculate the total surface area of a cylindrical tank of known diameter and height:

Formula 3:

Where:Asurface = total surface area of tank (square feet)D = diameter of tank (inches)H = height of tank (inches)

Pipe volume data: The data in table 1 can be used to calculate the volume of tubing in solar energy systems as well as other types of hydronic systems.

Tube type/size Gallons/foot3/8” type M copper: 0.0082721/2” type M copper: 0.01323/4” type M copper: 0.02691” type M copper: 0.0454

1.25” type M copper: 0.0681.5” type M copper: 0.0952” type M copper: 0.1652.5” type M copper: 0.25433” type M copper: 0.3630

3/8” PEX 0.0052941/2” PEX 0.0096095/8” PEX 0.013933/4” PEX 0.018941” PEX 0.03128

1.25” PEX 0.046681.5” PEX 0.065162” PEX 0.1116

3/8” PEX-AL-PEX 0.004891/2” PEX-AL-PEX 0.010385/8” PEX-AL-PEX 0.016583/4” PEX-AL-PEX 0.026541” PEX-AL-PEX 0.04351

Table 1

APPENDIX

H

h

heig

ht

of

tank

diameter of tank

D

Vtank =D2( )H924

Vfluid =D2( )h

924

Asurface =144

D2

2+ DH

34

APPENDIX 2:Expansion Tank Sizing for Solar Collection Circuits:

During its service life, almost every closed-loop solar collection system will experience stagnation conditions, where bright sunshine strikes the collectors without flow through the absorber plates. Under such conditions, the fluid within the collectors can change to vapor. In addition, the fluid within the piping to and from the collector array could be filled with very hot fluid.

To prevent the relief valve from opening under these conditions, the expansion tank must absorb the liquid volume expansion plus the fluid displacement volume caused by vapor formation in the collector array. The following procedure determines the minimum volume of a diaphragm-type expansion tank volume to accommodate this situation.

Step 1: Calculate the potential expansion volume of the entire collector circuit using formula 5a.

Formula 5a

Where:Va = expansion volume to be accommodated (gallons).Vc = total volume of collector array (gallons)Vp = total volume of collector circuit other than collector array (gallons)e = coefficient of expansion of collector circuit fluid (e = 0.045 for water, or e=0.07 for glycol)1.1 = safety factor of 10% to allow for system volume estimates

The volume of the collectors is usually listed in the manufacturer’s specifications, as is the volume of the heat exchanger. The volume of the piping can be estimated using data from table 1 in appendix 1.

Step 2: Calculate the static pressure at the location of the pressure relief valve. This is the pressure caused by the weight of fluid in the collector circuit above the pressure relief valve location. It can be calculated using formula 5b.

Formula 5b:

Where:Pi = initial pressure at the relief valve location (psi)H = height of collector circuit above location of

pressure relief valve (feet)0.454 = constant based on the density of 50% propylene glycol5 = allowance for 5 psi gauge pressure at top of

collector circuit

Note: The air chamber in the expansion tank must be pressurized to the pressure calculated using Formula 5b before fluid is added to the collector circuit.

Step 3: Calculate the minimum required expansion tank volume using formula 5c.

Formula 5c

Where:VT = minimum required expansion tank volume (gallons)Va = expansion volume to be accommodated (from step 1) (gallons)Pi = initial pressure at the relief valve location (from step 2) (psig)Pf = maximum allowed pressure at the relief valve location (psig). Recommended value is pressure relief valve rating minus 5 psi

Example: Determine the minimum expansion tank volume for the following system:

• 4 collectors, each having a volume of 1.5 gallons• Total of 120 feet of 1-inch copper tubing between heat exchanger and collector array• Heat exchanger volume = 2.5 gallons• Height of top of collector array above relief valve location = 25 feet• Pressure relief valve rating = 60 psi • Collector circuit fluid = 50% solution of propylene glycol

Solution:— Total collector array volume:4 x 1.5 = 6 gallons

— Total piping + heat exchanger volume:120 ft x (0.0454 gallon/ft) + 2.5 = 7.95 gallons

VT =VaPf +14.7

Pf Pi

35

Step 1:

Step 2:

— Pressure at relief valve under stagnation (relief valve rating – 5 psi): Pf = 60 – 5 = 55 psi

Step 3:

This procedure is “conservative” in several ways:• It assumes that all collector circuit piping contains fluid at the maximum system temperature.• It allows a 5 psi margin between the rated opening pressure of the relief valve and the pressure allowed to occur at the relief valve during stagnation.• It assumes that all the fluid in the collector array has changed to vapor under stagnation conditions.• It adds 10% to the estimated system piping volume.

A conservatively sized expansion tank is good “insurance” against the system requiring servicing following a stagnation condition.

In cases where the minimum required expansion tank volume exceeds the volume of available tanks, it is acceptable to use multiple tanks connected in parallel. Be sure the air side pressure in each tank is set to the calculated pressure (Pi) prior to filling the collector circuit.

APPENDIX 3: Domestic water-heating load estimating:

Formula 5 can be used to estimate the energy required for heating domestic water. A typical North American family uses about 20 gallons of hot water per day per person.Formula 5:

Where:EDHW = Daily energy required for domestic hot water (Btu)g = day requirement of domestic hot water required (gallons)Th = setpoint temperature of hot water heater (ºF)Tc = entering cold water temperature (ºF)

APPENDIX 4:Unit Conversion Factors:

Temperature

Temperature difference ( T):

Heat:

Power:

Pressure:

Volume:

Flow rate:

Solar heat intensity:

Inlet fluid parameter:

1º Ra = 0.555555º K1º F = .0555555º C

º F = º C (1.8) =32

0.555555º

36

circulator

circulator w/

circulator w/

gate valve

globe valves

ball valve

thermostatic

radiator valve

thermostatic

radiator valve

strainer

primary/secondary

cap

hose bib

drain valve

diverter tee

union

swing check valve

spring loaded

check valve

purging valve

metered

balancing

valve

pressure

relief

valve

brazed

plate

heat

exchanger

Modulating / condensing boiler

conventional boiler

indirect water heater (with trim)

GENERIC COMPONENTS

pressure &

temperature

relief valve

CALEFFI COMPONENTS

Modulating tankless water heater

solar collector array

pressure

reducing

valve

zone valve

(2 way)

zone valve

(3 way)

differential

pressure

bypass valve

VENT

Hydro

Separator

Hydrolink

manifold station with

balancing valves

pressure

relief valve

air & dirt

separator

DIRTCAL

dirt separator

high temperature

solar DISCAL

air separators

high temperature

solar pressure

relief valve

high temperature

solar air vent

high temperature

mixing valve

high

temperature

solar

expansion

tank

isolar

differential

temperature

controller

balancing

valve

high temperature

solar air vent

solar

circulation

station

37

The Caleffi Solar series of products are specifically designed for use in circuits of

solar systems. In these systems the heating fluid may contain glycol as additive

and may operate at high temperatures.

The materials and components used in its manufacture and the performance of

these must be suitable for these operating conditions.

Components for primary circuit - Solutions with glycol

+

– +

SET

38

Automatic air vent and shut-off valvefor solar systems250 series

Function

Automatic air vents are used in the closed circuits of solar heating systems to allow air contained inthe fluid to be released automatically during the filling process, by means of a valve operated by a float in contact with fluid in the system.The shut-off valves are used in combination with the automatic air vent vents to be able to isolatethem after filling the circuit of solar heating systems.

These series of products have been specially made to work at high temperature with a glycol medium..

Product range

Code 250041A Automatic air vent for solar systems size NPTCode NA29284 Shut-off valve for automatic air vent size 1/2

Technical specifications of 250 series valve

: - body: brass chrome plated- cover: brass chrome plated- control spindle: stainless steel- float: high resistance polymer- seals:

snoituloslocylg,retaw:muide%05:locylgfoegatnecrep.a

Working temperature range:

Technical specifications of valve NA29284

: - body: brass chrome plated- ball: brass chrome plated- seals:

snoituloslocylg,retaw:muide%05:locylgfoegatnecrep.a

Working temperature range:

Dimensions Dimensions

A1/2”

B4”

CØ 2 1/8”

D1/2”

C

B

D

A

Code250041A

Weight (lb)

0.7A

1/2”B

2 7/8”C

1/2”D

1 1/2”Code

NA29284Weight (lb)

0.5

A

A

B

D

C

Tmax = 180°C / 360°FPmax = 10 bar / 150 psi

CALEFFI

39

250 series

in high resistance r. Seals in high resistance elastomer. water glycol solutions. rcentageof 50%. Working re working ressur

ressur 75

Code NA29284

Seals in high resistance elastomer. water glycol solutions. rcentage of50%. Working re . working ressur 150

SPECIFICATION SUMMARIES

Operating principle

accumulation of air inthe valve causes the float to

occurs, anconsequently, the valve functionscorrectly, as long as the water

ressure remains theressure.

Installation

250 series automatic air

on the of the solarheating system at in the circuit where airgather that to

must always in with a shut-off valve.is necessary since the vent valves must shut off after use to

remove the air the filling starting the system.

Hydraulic characteristics

Discharge capacity when the system is

Construction details

Resistance to temperaturehigh rformance level of this series of automatic air vent

function with glycol res to

Application diagram

T max = 180 C / 360 FP max = 10 bar / 150 psi


T max

= 18

0C

/ 360

FP

max

= 10

bar

/ 15

0 ps

i

Tmax= 180C / 360FPmax=10bar/150psi

Tm

ax= 180C / 360

FP

max= 10 bar / 150 psi

Maintenance

allow checking of the internal mechanism.Access to the moving rts that govern the air

cover.A shut-off valve must re the

any maintenance work for shutting off after Tmax = 180 C / 360 FPmax = 10 bar / 150 psi


3.5

4.5

4.5

3.5

2.5

2 .5

1.5

1 .5

0.5

0

706050403020100

(bar

) (

psi)

)s/lN()MFCS(

1

0.1

0

0.5

0.90.80.70.6

0.40.30.2

1.2

1.1

0

2.5

0.25

0.5

0.75

1

1.25

1.5

1.75

2

2.25

40

Air separators for solar heating systemsDISCAL SOLAR251 series

Product range

Code 251003A Air separator for solar heating systems with drain size F NPT

Technical specifications

Materials: - body: brass chrome plated- cover: brass chrome plated

remylopecnatsiserhgih:taolf-leetssselniats:tnemelelanretni-

- float guide: brass- valve stem: dezincification resistant brass

leetssselniats:reveltaolf-leetssselniats:gnirps-

- seals: high resistance elastomer

snoituloslocylg,retaw:muideM%05:locylgfoegatnecrep.xaM

Working temperature range: Max. working pressure: Max. discharge pressure:

F NPT4/3Connections: - Main

Dimensions

Function

Air separators are used to continuously eliminate air from the primary circuits of solar heating systems. The air vent capacity of these devices is extremely high.They are able to automatically remove all the air from the solar circuits, includingmicrobubbles. The circulation of fully separated fluid allows the system to work underoptimal conditions without any trouble with noise, corrosion, local overheating andmechanical damage.

This particular series of air separaots has been specifically designed to work at hightemperature with a glycol medium, which is typical of solar heating systems.

A3/4"

B3”

C2 1/8”

D5 5/8”

F6 7/8”

Code251003A

Weight (lb)

2.0

CALEFFI

General

The removal of dissolved gases from a solar primary circuit is an essential process ina solar heating system. The presence of dissolved oxygen in a solar circuit causes rapidlocalized corrosion in collectors and heat exchangers. Carbon dioxide will dissolve in water, resulting in low pH levels and the production of corrosive carbonic acid. Low pH levels in a solar circuit causes severe acid attack throughout the solar heating system. While dissolved gases and low pH levels in the solar circuit can be controlled by theaddition of chemicals, it is more economical and thermally efficient to remove thesegases mechanically. This mechanical process is known as air separation and will increase the life of a solar heating system dramatically.

- Drain:

C

A

D

B

E

A

Tmax = 160 C / 320 FPmax = 10 bar / 150 psi

F

E1/2”

41

Operating principle

The air separator is composedof a set of metal screen surfaces arranged like spokes (A). Thisscreen creates a swirling motion to assist the release of micro-bubbles and their adhesion to the metal screen. The bubbles join and increase in size until thehydrostatic force increases to overcome the force of adhesionto the screen.Next, they rise to the top of thechamber where they are releasedby the float-operated automaticair vent valve (B).

B

A

The process of air formation

The quantity of air that can remain dissolved in solution in the waterdepends on the pressure and temperature.

release of air from the solution as the temperature increases andthe pressure decreases. This air is in the form of microbubbles withdiameters of approximately tenths of a millimeter.The microbubbles form continuously in the water of the solarheating systems on the top of the panels, because that is the pointin the circuit where the highest temperatures are reached.A portion of the air is re-absorbed as the medium reaches the partsof the circuit at a lower temperature. Because air remain the mediumit must be extracted.

System operation

necessary to expel all the air in the medium during the phases ofstart up and operation.The air separator permits separating and expelling this air fromthe fluid continuously and automatically. Any decrease in pressuredue to the release of air is compensated by the expansion tank or automatic filling unit.

AutomaticfillingTmax = 160 C / 320 F

Pmax = 10 bar / 150 psi


Tm

ax=

160

C /

320

FP

max

= 10

bar

/ 15

0 ps

i


Installation

The air separator must always be installed vertically and preferably:- before the pump to ensure a drop in pressure so microbubbles of air can develop.- on the return and in the bottom portion of the solar circuit where

there is no potential for formation of steam.

0.2

4

3

3.5

p (ft of water) (kPa)

10.5

0.2

5

0.3

0

0.3

5

0.4

0

0.4

5

0.6

0.7

0.8

0.9

1.2

1.4

1.6

1.8

2.5

4.0

4.52 3.0

3.5 5

Recommended max. flow

2 105 20

6 7 8 9 12 14 16 1833.

5 4

4.5

2.5

1.75

1.5

1.25

1.0

0.7

F (m

3 /h)

(gp

m)

0.1

0.05

0.090.080.07

0.06

0.0350.040.045

0.12

0.140.160.18

0.25

0.3

0.35

0.2

1

0.1

0.2

0.5

0.90.80.7

0.6

0.12

0.140.160.18

0.25

0.30.350.40.45

1.2

1.41.61.8

2.5

2

1

0.5

0.90.80.7

0.6

0.450.4

1.41.6

The maximum recommended speed of the fluid in the piping is 4.2 ft/sec, which is equivalent to a flow rate of 6.5 gallons per minute.




Discal air separator is built to permitmaintenance and cleaning operationswithout having to remove the valvebody from the pipe.Access to the moving parts that control the air vent is attained by simply removing the top cover.

Resistance to heat and high discharge pressure, allows the maintenance of the functional features of the air separator with glycol water temperatures

the air separator has been designed to discharge the air up to a pressure of 150 psi.

42

High-performance automatic air ventDISCAL SOLAR251 series

Product range

F NPT2/1ezissmetsysgnitaehralosrofevlavtnevriacitamotuaecnamrofrep-hgiH4A00152edoC


Materials: - body: brass, chrome plated- cover: brass, chrome plated

remylopecnatsiserh-gih:taolf-- float guide: brass- valve stem: dezincification-resistant alloy

leetssselniats:reveltaolf-leetssselniats:gnirps-

- hydraulic seals: high resistance elastomer

snoituloslocylg,retaw:muideM%05:locylgfoegatnecrepx.aM

Dimensions

Function

DISCALAIR solar devices are used in hydronic systems or in the filling and start-upphase of solar heating systems to discharge even large quantities of air that haveformed in the circuits. This function is performed even when there is considerablepressure thanks, to the special geometry of the discharge mechanism, which isidentical to the mechanism on DISCAL Solar 251 series air separators.

This particular series of automatic air vent valves has been specifically designed towork at high temperatures with a glycol medium, typical of solar heating systems.

A1/2"

B4 1/2”

C1 3/8”

D2 1/8”

Weight (lb)1.3

Code251004A

D

B

A

C


CALEFFI

Working temperature range: Max. working pressure: Max. discharge pressure:

F NPTConnections:

43

Operating principle

The accumulation of air bubbles inthe valve body causes the float todrop so that the valve opens.This action, and correct air valvevalve operation, is ensured aslong as the water pressureremains under the maximumdischarge pressure.

Installation

DISCALAIR series 251automatic air vent valvesmust be installedvertically, typically on thetop of solar heating system panels and at points in the circuit wherebubbles of air gather that must be discharged.They must always be installed in combination with a shut-off valve.This is necessary since the vent valves must be shut off after use toremove the air as the system is filling and starting up.


Discharge capacity in the phase of filling the system


Resistance to heat and high discharge pressureThe high performance of this series of automatic air vent valves,required in solar heating systems, is ensured by the use of heatresistant materials.The materials allow the vent function with glycol water temperatures

to discharge air up to a pressure of 150 psi.

Application diagram

T



Tm

ax=

160

C / 3

20F

Pm

ax=

10 b

ar / 1

50 p

si


Tm

ax= 160

C / 320F

Pm

ax= 10 bar / 150 psi

Maintenance

The DISCALAIR automatic air vent valve isbuilt to permit inspection of the internalmechanism.Access to the moving parts that govern the airvent is attained by simply removing the topcover. In addition, the body can be separatedfrom the bottom portion connected to the pipe.A shut-off valve must be installed before theDISCALAIR device to allow for shut off afterthe filling phase and to simplify any maintenancework.


DISCAL SOLAR 251 seriesHigh-performance automatic air vent valve for solar heating systems. Connections . Brass body, chrome plated. Highresistance polymer float. Stainless steel float lever and spring. Brass float guide. Dezincification-resistant alloy release stem. Highresistance elastomer hydraulic seals. Medium water and glycol solutions; maximum percentage of glycol 50%. Temperature range

Maximum working pressure 150 psi. Maximum discharge pressure 150 psi.


1

0.1

0

0.5

0.9

0.8

0.7

0.6

0.4

0.3

0.2

1.2

1.1

0

2.5

0.25

0.5

0.75

1.0

1.25

1.5

1.75

2.0

2.25

3.25

2.75

3.0

1.3

1.5

1.4

3.5

4.0.5

4.5

5.0.5

5.5

6.0.5

3.0.5

2.5

2.0 .5

1.5

1.0 .5

0.5

0

9080706050403020100

(bar

) (

psi)

7.5

8.0.5

8.5

9.0.5

9.5

10.5

7.0.5

6.5.5

150

140

130

120

110

100

)s/lN()MFCS(

44

Adjustable thermostatic mixing valvefor solar systems

Function

The thermostatic mixing valve is used in systems for scald protection in the production of domestic hot water.It is designed to maintain the set temperature of the mixed water suppliedto the user when there are variations in the temperature and pressure

This particular series of mixing valves can function continuously at the hightemperatures of the incoming hot water from the solar storage tank.

Product range

sizeCode 2521 series Adjustable thermostatic mixing valve for solar systemssizes e for solar systems


Materials: - body: dezincification resistant alloy brass USP:rettuhs-leetssselniats:sgnirps-

MDPE:stnenopmoclaes-

Setting range:Accuracy:

Min. temperature difference between hot water at inlet and mixed water at outlet for optimum perforMin. flow rate to ensure stable temperature:

Connections: - 2521 version:- :

Dimensions

A1/2”3/4”

B2 1/4”2 1/2”

D5 5/8”5 7/8”

E3 1/8”3 1/4”

F2 5/8”2 5/8”

C4 1/2”

5”

Code252149A252159A

Weight (lb)

2.22.4

AF

ED

B BC

A

A

HO

T

COLD

MIX

MIN MAX 712

A

FE

D

B BC

A

A

E3 1/4”3 3/4”

D6 3/4”7 1/4”

C6 1/4”7 1/4”

F3 1/2”3 1/2”

B3 1/8”3 5/8”

Weight (lb)

5.35.6

A3/4”

1”

Code252359A252369A

CALEFFI

MIN MAX 712

CALEFFI

1” 3 1/8” 6 3/8” 3 7/8” 2 5/8”6 1/4”252169A 2.6

NSF. ASSE 1017

- 2521- :

General

the danger of scalding.

252 series

45

Temperature adjustment

The temperature is set at the desired value by the knob with thegraduated scale, located on the top of the valve.

Temperature adjustment table

Position Min. 1 2 3 4 5 6 7 Max.

T 135 145

Reference values: Thot = Tcold = Hot and cold water inlet pressures = 45 psi

Locking the setting

After selecting the temperature, thesetting can be locked at the desiredvalue using the control knob.To do this, unscrew the lock screwon the upper part of the control knob,remove the knob and put it back on so that the internal reference coupleswith the protrusion on the knob carrierring nut.

Use

Thermostatic mixing valves are typically installed at the outlet of hotwater storage tanks in solar systems to ensure constant temperatureof the mixed water supplied to the end user. Because of their flow characteristics, the valves can be installed to control the temperaturefor both single point of use and for point of distribution. In order toguarantee the delivery of mixed water at the set temperature, thethermostatic mixing valves must have a minimum flow rate of:2521 series min. flow of 1.3 gpm2523 series min. flow of 2.3 gpm

MINMAX

7

12

3

Shut-off valve

Pressure reducing valve

Air gap

Check valve

T/P safety valve

Temperature gauge

Expansion vessel

Automaticdiverting valve

Thermostat

Pump

Safety valve

HOT

COLD

CALEFFI

MIN

MAX

71

2

T

Normally closedvalve

T

T

Application diagrams - System with thermal integration

The controlling element of the solar thermostatic mixing valve is atemperature sensor that is fully immersed in the mixed water outlet passage. As it expands or contracts, the sensor continuously establishes the correct proportion of hot and cold water entering the valve. The flowis regulated by a piston sliding in a cylinder between the hot and coldwater passages.Even when there are pressure drops due to the drawing off of hot or cold water for other uses or variations in the incoming temperature,the mixer automatically regulates the water flow to obtain the required temperature.

Operating principleInstallationBefore installing the mixing valve, the pipework must be flushed outto ensure that there are no circulating impurities to harm the system.We recommend always installing filters of sufficient capacity at theinlet of the water system.

Thermostatic mixing valves can be installed horizontally or vertically.

The following are indicated on the body of the mixing valve:

p (psi) (bar)

1.00

10 20 50

2.0

4.0

8.0

20Flo

w ra

te(l/

min

) (g

pm)

0.70

0.35

0.20

0.14

0.07

0.03

15

10

5

3

2

1

0.5

25232521Hydraulic characteristics

46

Differential temperature controllers iSolar257 series

Function

A multi-functional temperature differential controller with add-on system functions, the iSolar series can be used for a wide variety of applications and has inputs for four PT1000 sensors. Preset factory defaults are defined for control of a standard solar water heating system with a second relay (some models) to divert any surplus heat. The auxiliary relay can be used to maintain the tank temperature, protect the system from overheating, or use another source to heat the storage tank.

This controller features a large Liquid Crystal Display (LCD) user interface with three function keys. The easy-to-use icons assist to operate and customize a solar heating system.

Product range

Code 257210A iSolar1 controller with 1 standard output relay for pump control, includes 3 temperature sensorsCode 257220A iSolar2 controller with 1 electronic output relay for pump speed control, includes 3 temperature sensors


Dimensions

CALEFFI

Housing plastic: PC-ABSProtection type: Indoor onlyMounting: wall or in 255 series pump station

Display: LCD with symbols and textInterface: three soft push buttons

Inputs: 4 temperature sensorsOutputs: 1 or 2 electronic or standard relaysSwitching relay capacities: 2 (1) A 115VPower supply: 115 V - 60 HzBus interface: V-Bus

Performance

ent range:

Hysteresis:

Max. tank temperature range: Max. collector temperature range: Emergency shut down of the collector: Min. collector temperature range:

Antifreeze temperature option:kWh (BTU) flow input:

Agency approvals

Temperature sensors

Collector sensor working range: Tank sensor working range:Length of collector cable: 60 in. (1.5 m)Length of tank sensor cable:

14 23 32 41 50 68 77 861000 1058 1078 1117

104 113 122 131 140 158 1671136 1155 1175 1213 1232 1252 1271

176 185 203 212 221 2301328 1347 1366 1385 1404 1423 1442 1461

Resistance values

Code 257230A iSolar3 controller with 2 standard output relays for pump control, plus valve or second pump control, includes 3 temp. sensorsCode 257260A iSolarPlus controller with 2 electronic output relays for pump speed control, plus valve or second pump control, includes 3 sensors

USUSCCUL 60730-1A

A4 3/8”

B6 3/4”

C6”

D2”

A

B

D

Code250041A

Weight (lb)

0.9

C

47

Selectable systems Characteristics

+

– +

SET

!

FR

System screen LCD displaywith 16-segment display and8 symbols for system status

Operating LED control lamp

3 push-button controls

Attractive design and compact dimensions

Easy to install

User-friendly operation

S1

S2S4 / TRL

R1

S3

S1

S3

S4

R1

R2

S2

Tank 1 Tank 2

R2

S1

S2

R1 S3

S4 / TRL

R2

S4 / TRL

S1

R1

S2 S3

Tank 1 Tank 2

S1

S2 S3R1 R2

Tank 1 Tank 2S4 / TRL

R1

R2

S1

S2

S3 S1

S4

S2

S3R1

R2

S1

S3

S2

S4

R2

R1

Standard system with 1 tank, 1 pump and 3 sensors. S4 / TRF can be used as BTU meter

System and heat exchange with an existingtank with 1 tank, 4 sensors and 2 pumps

Solar system and backup heating with 1 tank, 3 sensors. S4 / TRF can be used as BTU meter

2-tank-solar system with valve logic, 3 sensors, 1 solar pump and 3-way valve. Sensor S4 / TRF can used as BTU meter

2-tank solar system with pump logic, 3sensors and 2 solar pumps

Solar system with east-west collectors, 1 tank, 3 sensors and 2 solar pumps.

System with backup heating by wood boilerwith 1 tank, 4 sensors, 1 solar pump and 1 pump for backup heating.

System and heating circuit pre-heat with1 tank, 4 sensors, 1 solar pump and 3-wayvalve for heating circuit.

S2

R1S3R2

S1

S4 / TRL

System and tank charge in layers with 1 tank,3 sensors, 1 solar pump and 3-way valve.Sensor S4 / TRF can be used as BTU meter

R2

S1

S2

R1 S3

S4 / TRL

Solar system and heat dumping with 1 tank, 3 sensors. S4 / TRF can be used as BTU meter

iSolar 1 iSolar 2 iSolar 3 iSolar Plus

Electronic relayy 0 1 0 2

Standard relay 1 0 2 0

Pump speed control no yes no yes

Operating hours counter yes yes yes yes

kWh (BTU) measurement yes yes yes yes

V-bus for data recorder yes yes yes yes

PC-interface RS232 yes yes yes yes

Heat dumping function no no yes yes

Backup heat function no no yes yes

Additional T control no no no yes

Two-tank priority no no no yes

Clock with scheduling no no no yes

A062752A013752A022752A012752edoC

Selectable programs 1 1 2 9

Standard operation functions

- When the switch-on difference is reached, the pump is activated until the differential temperature drops below.Maximum tank temperature - When the adjusted maximum tank temperature is exceeded, the pump switches off.Collector emergency shutdown - If adjusted collector temperature is exceeded, the solar pump is switched off.System cooling - If the temperature rises to the maximum collector

temperature the solar pump remains on until the temperature drops.Minimum collector temperature - a minimum set temperature which must be exceeded before the solar pump is switched-on.Antifreeze function - If the adjusted temperature drops, the solar pump is switched on to protect the fluid from freezing.

- In the evening, the solar pump continues running until the storage tank is cooled down.

- The controller measures an increase of heat rise in the collector and adjusts operation for maximum efficiency.

- The heat generated is measured by the flow and the temperature of feed and return sensors.Operating hours counter - Operating hours counter stores the solar operating hours of the respective relay.Manual operating mode - For control and servicing, the operating mode of the controller can be switched manually.

Heat dumping function - Heat dumping works independently from the solar operation and activates the second relay.Backup heating function - Backup heating works independently from the solar operation and activates the second relay.

- The differential temperatures can be adjusted separately.Priority tank / tank rotation - The controller checks the temperatures and rotates or gives priority to charging two tanks.East / West collectors solar pump based on collectors and the one-tank temperature.

Advanced operation functions (some two-relay models)

Pump speed control functions (some models)

Pump speed control can improve system efficiency by reducing the flow tothe collectors on cloudy days to improve solar thermal transfer and reduce electrical consumption. This is achieved by the differential temperature value between the collectors and storage tank.

will start with 100% pump speed for 10 seconds, then reduce the speed to

speed will increase by 10% until the maximum of 100% is reached.

Model selection

48

Solar pump stations for solar heating systems255 - 256 series

Product range

Code 255056A Dual pump station, flow and return connection, flow meter scale: 1/2 m size 3/4Code 255059A Dual pump station, flow and return connection, flow meter scale: 1/2 m size 3/4 sweat unionsCode 255060A Dual pump station, flow and return connection, flow meter scale: 1/2 m size

Code 256059A return connection, flow meter scale: 1/2 m size 3/4 sweat unions


Function

Wilo Star S-16 U15 hydraulic characteristics

CALEFFI

steel / aluminium

Seals:

Safe

: 1/4

Adjust 1/4 to 5

Connections: on

Wilo solar model: Star S-16 U15 cast iron

16

14

12

10

8

6

4

2

0 2 4 6 8 10 12 14 16 18

3

1

2

3

Wilo pump

Performance

General

s

49

Characteristic components

The shut-off and check valves are built into the ball valves of the temperature gauge connectors.To allow the fluid to flow in both directions, it is necessary to open the respective ball

In normal system operation, the ball valves must be fully open.


14

A

1 Wilo-Solar circulation pump

2 Safety relief valve 253 series

3 Filling/drain valve

4 Pressure gauge

5 Flow meter

6 Air trap and vent

7 Flow temperature gauge

8 Return temperature gauge

9 Pre-formed insulation shell

10 Shut-off and check valve

11 Expansion Tank connection kit

12 plug (used if no expansiontank is installed)

Dimensions

A3/4”3/4”1”

B4”4”4”

C4 7/8”4 7/8”4 7/8”

D15”15”13”

E8”8”8”

F16”16”16”

Code255056A255059A255060A

Weight (lb)

151515

AA

B C

AA

E

DF

A3/4”

B7”

C16 1/4”

D17”

E5”

Code256059A

Weight (lb)

10

A

B

A

E

C

D2

5

1

12

6

3

9

8

7

10

4

11

Air trap

The solar pump unit version with flow and return connection is equipped with an air trap on the flow line. The gases, separated from the fluid, are collected at the top of the trap.

The collected gases must be released from time to time - every day after the initial installation; however, it can eventually be done weekly or monthly, depending on the quantity of the air. The collected gases are released using the manual air vent with ascrewdriver. To maintain optimal efficiency of the solar heating system, it is necessaryto vent the system every six months by using the manual air vent.

B

50

Safety relief valve for solar systems

253 series

General

The safety relief valves manufactured by Caleffi are produced in compliance with the essential safety requirements of the Directive97/23/EC of the European Parliament and the Council of the EuropeanUnion for the Harmonization of Member States with regard to pressurizedequipment.

Function

These safety relief valves are used to control pressure in the primarycircuits of solar heating systems.When the calibrated pressure is reached, the valve opens to releasethe fluid into the atmosphere and prevents the pressure in the systemfrom reaching levels that might damage the solar collectors andequipment.These particular series of products have been specially made and certifiedto work at high temperature with a glycol medium.

Product range

253 series Safety relief valve for solar systems size F x F

11

15


Materials: - body: brass chrome plated- control spindle: brass- relief seal: high resistance elastomer

stainless steel:gnirps-03G6AP:bonklortnoc-


Normal pressure: 150 psi (10 bar)Working temperature range:

VIPED section::lavorppA

F4/3xF2/1:snoitcennoC

Performance

%01:erusserprevogninep%02:laitnereffidgnisolC

:y: 171,000 BTU (50 kW)ticapacegrahcsiD

Code 253043 253044 253046 253048 253040Preset psi (bar)

Dimensions

A1/2"

B3/4"

C1”

D2 3/4”

E1 3/8”

AE

D

CB

Code25304_

Weight (lb)

0.3

CALEFFI

T V Rheinland is an approved U.S. Nationally

Certification Body for Pressure Equipment

CALEFFI

51

253 seriesSafety relief valve for solar heating systems. CE mark as per Directive 97/23/EC. certified for solar systems. F x 3/4 Fthreaded connections. Brass body. Chrome plated. Diaphragm and disk seal in high resistance elastomer. Spring of stainless steelControl knob of PA6G30. Temperature range: . Nominal pressure: . Calibration setting:


Operating principle

and fully opens the outlet vent.The preset pressure is chosenaccording to the maximum permissible pressure in the solarheating system.The diameter of the out let

inlet in order to help dischargethe required volume.As the pressure decrease, the

the preset tolerances.

Discharge pipe


Temperature and glycolIn solar systems, heating fluid of the primary circuit contains glycolas an additive and operates at high temperatures. Because of these particular operating conditions, the valve disk seal of the safetyvalve is made of high resistance elastomer.The knob is made of plastic material especially resistant to increasesin temperature and to rays, in the case of outdoor installations.

Chrome platingThe valve body is chrome plated to protect it from dirt and moisture,in the case of outdoor installations of solar heating systems.

Certification253 series safety relief valves are certified for specific use in solarheating systems by the certifying body , in accordance

T

InstallationThe safety relief valves for solar systems must be installed near the

tank.sure there are no shut-off devices the valve and the

rest of the system.The safety relief valves can be fitted vertically or y but

This prevents deposits of impurities from affecting correct functioning.

indicated by the arr on the valve body.

1

2

3

Application diagram

This valve should only be used and properly installed so that spillageof glycol could not cause damage. To avoid damage due to valve operation, a discharge pipe must be installed. It should terminate

container or through

piped into a suitable container or other suitable place of disposal. Under nocircumstances should the vent openingor drain line be plugged.

52

Expansion tanks for pressurized systemsSolarPlus259 series

General

Product range

Code 259 series SolarPlus expansion tanks for pressurized solar heating systems sizes 3, 5, 7, 9, 13 gallons


Materials: - body: welded steel- coating: epoxy paint- diaphragm: EPDM


System temperature range: 15...

Max. working pressure: Pre-charged pressure:

Dimensions Dimensions

A

3/4”

B

11 7/8”

C

15 1/2”

D

3/4”

A

Code

250025

Size (gal)

7

A B C DCode Size (gal)

B

C

CALEFFI

.

A

D

C

D

B

3/4” 10 5/8” 13 3/4” 3/4”250018 53/4” 10 5/8” 10 5/8” 3/4”250012 3 3/4” 15 3/4” 16” 1”259035 9

3/4” 21 1/8” 16” 1”259050 13

pre-charged pressure.

Function

Mounting feet for wall installation.

CALEFFI

53

012345

0

20

40

6080

100

120

140

1600

20

40

6080

100

120

140

160

0

1

23

4

5

6

Shut-off valve

Pump

Air vent

Expansion vessel

Safety relief valve

Installation

The expansion tank can be installed after the flow check valve on the outlet side of the circulationpump, between the solar collector (exit pressure), or it can be on the inlet side of the circulation pump(entrance pressure). Since there can be no check valve between the collector and the expansion tank, the expansion tank should be installed on the outlet side of the pump (exit pressure).

+

– +

SET

A expansion tank connection kit, consisting of a flexible stainless steel hose, a double automatic shut-off valve, wall bracket and mounting hardware, helpsreduce installation time and provides suitable mounting.

Code: 255001

Max. working pressure: 150 psi (10 bar).

Hose length: 20 in. (500 mm).

Bracket for expansion tank with a maximum capacity of 7 gallons.

0

20

40

6080

100

120

140

160

0

1

23

4

5

6

Accessories

54

Flexible stainless steel insulated pipingSolarFlexNA3540-15

Function

Product range


: -

-outer cover:-

Dimensions

CALEFFI

t

General

A3/4”

B15/16”

C4 ”

D2 1/8”

CodeNA3540-15

Weight (lb/f)

0.5


5

A B

C

D

55


Flexible stainless steel pipe

UV resistant protection film

Closed cell elastomeric EPDM foam insulation

Integrated two-wiresensor cable

Installation of union nuts

Flow and return pipes are easy to separate without damaging the insulation or sensor cable.

SolarFlex pipe is a flexible, quick installation system to connect solar collectors to the pump station and to the storage tank. The pipe systemis easy to install, enabling pipes to be run without using a torch inconfined spaces or on the roof. Two closed cell elastomeric foam extrusions of high temperature resistant EPDM are protected against damages by a common outer cover. Flow and return pipes can be easily separated without damaging the insulation.

SolarFlex is the way to reduce installation time while ensuring a leak-

require special tools or time.

General

Optional pipe hangers keep pipe secure and reduce installation time.

Cut pipe with tubing cutter. Do notuse a hack saw.

without flat-sealing washer.

Remove union nipple to inspectflat-sealing surface.

segment ring around pipe groove.

Forming a flat-sealing surface.

Insert flat-sealing washer and connect to other fittings.

Cut the length of pipe required to connect solar collector to the solar

Any remaining short sections of pipe can be used for tank connectionor other connections. Use connection kit NA1210-3,

nuts, segments rings and sealing washers.

Model Description

NA637204

0

2

4

254462

255862

Fitting for connecting to collectors and tanks

Using cut sections of pipe

2 Panel/80 Gallon Tank System3-5 People, 60 gallons use per day

Using Viessmann Flatplate CollectorQty Item # Description

2 7248-395 VITOSOL 100-F, FLAT PLATE COLLECTOR1 7248-239 INTERCONNECTION PIPES BETWEEN COLLECTORS1 7248-240 GENRAL CONNECTION SET1 7174-993 SENSOR WELL SET1 Z003-098 MOUNTING HARDWARE1 7134-449 INSTALLATION FITTINGS SET1 SSU-80SB SUPERSTOR STAINLESS SOLAR TANK1 255059A SOLAR CIRCULATION UNIT1 253046 3/4" FPT 90 PSI SAFETY VALVE1 257230A I SOLAR 3 DIF TEMP CONTROLLER 1 259025 7 GAL HIGH TEMP EXPANSION TANK1 255001 3/4" STRAIGHT EXPANSION TANK CONNECTION KIT1 7316-098 TYFOCOR-HTL SOLAR FILL1 NA3540 SOLFLEX CONNECTION PIPING 50' INSULATED4 NA10061 3/4" SOLFLEX TO 3/4" COPPER SWEAT FTG1 251003A 3/4" SOLAR IN-LINE AIR SEPERATOR

50 gal/Day121.5 °F

2 x Vitosol 200 FTotal Gross Surface Area: 53.99 sq.ft

Azimuth: 0°Incl:30°

Vitocell-H 100 (130 Liter) Vitocell-H 300 (350 Liter)Vitola 100 22 kW

Results of Annual Simulation

Page 1

Line 1: Please enter under OptionsLine 2: Please enter under Options2.80 Flat Plate SystemVariant1

T*SOL Pro 4.4 7/3/2008

Installed Collector Power: 11.98 kBtu/hr

Collector Surface Area Irradiation: 25.79 MBtu 514.75 kBtu/sq.ft

Energy Produced by Collectors: 11.34 MBtu 226.44 kBtu/sq.ft

Energy Produced by Collector Loop: 9.89 MBtu 197.49 kBtu/sq.ft

DHW Heating Energy Supply: 10.98 MBtu

Solar Contribution to DHW: 9.09 MBtu

Energy from Auxiliary Heating: 3.39 MBtufuss

kopf

Fuel Oil Savings: 102.1 gal

CO2 Emissions Avoided: 2,267.93 lbs

DHW Solar Fraction: 72.9 %

Fractional Energy Savings (prEN12976):

73.3 %

System Efficiency: 35.2 %fuss

Basic Data

Page 2


T*SOL Pro 4.4 7/3/2008

Climate File

Location: Boston MA

Weather Data Record: "Boston MA"

Global Radiation Annual Total: 4.86 MBtu

Latitude: 42.37 °

Longitude: 71.05 °

Domestic Hot Water

Average Daily Consumption: 50 gal

Desired Temperature: 121.5 °F

Load Profile: Detached House (evening max)

Cold Water Temperature: February:45.48 °F / August:52.72°F

Fuss

System Components

Collector Loop

Manufacturer: Viessmann Werke GmbH & Co

Type: Vitosol 200 F

Number: 2.00

Total Gross Surface Area: 53.992 sq.ft

Total Active Solar Surface Area: 50.095 sq.ft

Inclination (Tilt Angle): 30 °

Azimuth: 0 °

DHW Standby Tank

Manufacturer: Viessmann

Type: Vitocell-H 100 (130 Liter)

Volume: 34.34 gal

Solar Preheating Tank (S)



Volume: 92.46 gal

Auxiliary Heating

Manufacturer: ViessmannFuss

Original T*SOL Database

With Test Report

Solar Keymark

System Components

Page 3


T*SOL Pro 4.4 7/3/2008

Type: Vitola 100 22 kW

Nominal Output: 75.06 kBtu/hrFuss


With Test Report

Solar Keymark


T*SOL Pro 4.4 7/3/2008

Solar Energy Consumption as Percentage of Total Cosumption

Solar System 9,122,921 Btu Total Energy Consumption 12,521,862 Btu

DecNovOctSepAugJulJunMayAprMarFeb

[ Btu

]300,000280,000260,000240,000

220,000200,000180,000160,000140,000120,000100,000

80,00060,00040,00020,000

0

Daily Maximum Collector Temperature

DecNovOctSepAugJulJunMayAprMarFebJan

[ °F

]

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

These calculations were carried out by T*SOL Pro 4.4 - the Simulation Programme for Solar Thermal HeatingSystems. The results are determined by a mathematical model calculation with variable time steps of up to 6minutes. Actual yields can deviate from these values due to fluctuations in the weather, consumption and otherfactors.The Schematic System Diagram above does not represent and cannot replace a full technical drawing of thesolar system.

Report-/Druckmodul List & Label Version 11.0: Copyright combit GmbH 1991-2005

0

10

20

30

40

50l

0

20

40

60

80

100

120

140kg

0

20

40

60

80

100%

0

200,000

400,000

600,000

800,000

1,000,000Btu

Variant1

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecTime Period 1/ 1/ - 12/31/

Saving Fuel Oil 387 l CO2 Emissions Avoided 1,029 kgDHW Solar Fraction 73 % Efficiency 35 %E Solar - DHW 9,122,921 Btu

3 Panel/119 Gallon Tank System5-7 People, 75 gallons use per day

Using Viessmann Flatplate CollectorQty Item # Description

3 7248-395 VITOSOL 100-F, FLAT PLATE COLLECTOR1 7248-239 INTERCONNECTION PIPES BETWEEN COLLECTORS1 7248-240 GENERAL CONNECTION SET1 7174-993 SENSOR WELL SET1 Z003-098 MOUNTING HARDWARE1 7134-449 INSTALLATION FITTINGS SET1 SSU-119SB SUPERSTOR STAINLESS SOLAR TANK1 255059A SOLAR CIRCULATION UNIT1 253046 3/4" FPT 90 PSI SAFETY VALVE1 257230A I SOLAR 3 DIF TEMP CONTROLLER 1 259025 7 GAL HIGH TEMP EXPANSION TANK1 255001 3/4" STRAIGHT EXPANSION TANK CONNECTION KIT1 7316-098 TYFOCOR-HTL SOLAR FILL1 NA3540 SOLFLEX CONNECTION PIPING 50' INSULATED4 NA10061 3/4" SOLFLEX TO 3/4" COPPER SWEAT FTG1 251003A 3/4" SOLAR IN-LINE AIR SEPARATOR

75 gal/Day121.5 °F

3 x Vitosol 200 FTotal Gross Surface Area: 80.99 sq.ft

Azimuth: 0°Incl:30°

Vitocell-H 100 (130 Liter) Vitocell-H 300 (500 Liter)Vitola 100 22 kW

Results of Annual Simulation

Page 1

Line 1: Please enter under OptionsLine 2: Please enter under Options2.80 Flat Plate System3.120

T*SOL Pro 4.4 7/3/2008

Installed Collector Power: 17.97 kBtu/hr

Collector Surface Area Irradiation: 38.68 MBtu 514.75 kBtu/sq.ft

Energy Produced by Collectors: 16.48 MBtu 219.27 kBtu/sq.ft

Energy Produced by Collector Loop: 14.93 MBtu 198.72 kBtu/sq.ft

DHW Heating Energy Supply: 16.47 MBtu

Solar Contribution to DHW: 13.83 MBtu

Energy from Auxiliary Heating: 4.24 MBtufuss

kopf

Fuel Oil Savings: 154.7 gal

CO2 Emissions Avoided: 3,434.59 lbs

DHW Solar Fraction: 76.5 %

Fractional Energy Savings (prEN12976):

77.1 %

System Efficiency: 35.8 %fuss

Basic Data

Page 2


T*SOL Pro 4.4 7/3/2008

Climate File

Location: Boston MA

Weather Data Record: "Boston MA"

Global Radiation Annual Total: 4.86 MBtu

Latitude: 42.37 °

Longitude: 71.05 °

Domestic Hot Water

Average Daily Consumption: 75 gal

Desired Temperature: 121.5 °F

Load Profile: Detached House (evening max)

Cold Water Temperature: February:45.48 °F / August:52.72°F

Fuss

System Components

Collector Loop

Manufacturer: Viessmann Werke GmbH & Co

Type: Vitosol 200 F

Number: 3.00

Total Gross Surface Area: 80.988 sq.ft

Total Active Solar Surface Area: 75.143 sq.ft

Inclination (Tilt Angle): 30 °

Azimuth: 0 °

DHW Standby Tank



Volume: 34.34 gal

Solar Preheating Tank (S)



Volume: 132.09 gal

Auxiliary Heating

Manufacturer: ViessmannFuss


With Test Report

Solar Keymark

System Components

Page 3


T*SOL Pro 4.4 7/3/2008

Type: Vitola 100 22 kW

Nominal Output: 75.06 kBtu/hrFuss


With Test Report

Solar Keymark


T*SOL Pro 4.4 7/3/2008

Solar Energy Consumption as Percentage of Total Cosumption

Solar System 13,880,614 Btu Total Energy Consumption 18,138,892 Btu

DecNovOctSepAugJulJunMayAprMarFeb

[ Btu

]440,000420,000400,000380,000360,000340,000320,000300,000280,000260,000240,000220,000200,000180,000160,000140,000120,000100,000

80,00060,00040,00020,000

0

Daily Maximum Collector Temperature

DecNovOctSepAugJulJunMayAprMarFebJan

[ °F

]

190

180

170160

150

140130

120

110100

90

80

7060

50

40

These calculations were carried out by T*SOL Pro 4.4 - the Simulation Programme for Solar Thermal HeatingSystems. The results are determined by a mathematical model calculation with variable time steps of up to 6minutes. Actual yields can deviate from these values due to fluctuations in the weather, consumption and otherfactors.The Schematic System Diagram above does not represent and cannot replace a full technical drawing of thesolar system.

Report-/Druckmodul List & Label Version 11.0: Copyright combit GmbH 1991-2005

0

10

20

30

40

50

60

70

80l

0

50

100

150

200kg

0

20

40

60

80

100%

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000Btu

3.120

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecTime Period 1/ 1/ - 12/31/

Saving Fuel Oil 585 l CO2 Emissions Avoided 1,558 kgDHW Solar Fraction 77 % Efficiency 36 %E Solar - DHW 13,880,614 Btu

Project Information

Heating Contractor Project Information

Company Name: Customer Name:

Contact Name: Street:

Phone: City:

Fax: State, Zip:

Cell:

Installation Area 3. Roof Construction:(Check One) (Check One)

Slope Roof Asphalt Shingle

Flat Roof Tar & Gravel

Other Roof Tile

OtherIs there any shading? Yes No

Collector Alignment Collector Inclination_______________° Available Roof Surface Area

Deviation from South ° Legnth:______________________

Width: ______________________

Solar Project Check List

Solar Project Check List

Building Data

New Construction Retrofit

Pipe length from collector to solar storage tank (one way): feet. # of floors:

Mechanical room location: Basement Roof Other:

Solar System Use

DHW Heating Swimming Pool Heating Space Heating Support

DHW Heating Load

Residential Home How many people in home? DHW usage: USG/day

# of bathrooms: Whirlpool tub size: USG

Multi-family/Apartment # of units: Average # of people per uit:

DHW usage: USG/day Recirc loop Yes No

Other DHW Application Building type: DHW usage: USG/day

DHW Temperature Desired f DHW use pattern: Is it the same all year? Yes No

Swimming Pool Heating

Open Air Pool Location: Wind exsposed Wind protected

Indoor Pool Period of use: June - August May - September

Swimming Pool Size (L/W/D): / / ft. Pool Volume:(LxWxDx7.5) USG

Desired Pool Temperature: f Pool cover used: Yes, hrs/day used: No

Backup reheating available Yes No If Yes, what type:

Space Heating Support

Size of heated area: s.f. Building heat load: MBH

High temp heating (radiator/fan coil) System temp: f % of building heated:

Low temp heating (radiant floor) System temp: f % of building heated:

Installed boiler output: MBH Fuel type:

Example: Family of 51 What is the hot water demand per day?

Most common multiplier is 20 gals pp/pd

5 * 20 = 100 gals/day

2 What is the BTUH requirement to heat the water?Multiply gals by BTU/lb multiplier by delta T of water

100 * 8.3 * 65 = 53,950 BTU/day

3 What type of collector do you want to use?

4 How many BTU/day are the collectors capable of?Use row D of SRCC Rating for safety (Water Heating Cool Climate)(Ti-Ta = Fluid Temp at collector Versus Ambient Air Temp at Collector)

s.f. BTU/s.f/d BTU/s.f/d CollectorsD rating C rating Needed

Viessmann 100 Series Flat Plate 27.16 22k 30k 3Buderus SKS 4.0 25.95 19k 28k 3

5 Once you have determined the number of collectors, determine the flow requirements.

Collector Collector Example

p.d. flow flow rate

Viessmann 100 Series Flat Plate .25 iwc .79 gpm 2.4 gpm

6 Select piping size between collector like any other hydronic system. Rule of Thumb: (50' or less)1/2" piping will support 2-4 collectors 3/4" piping will support 4-8 collectors.1" piping will support 8-12 collectors.

Collector Type

Collector Type

SIZING A SOLAR DHW SYSTEM

7 Storage Tank Sizing.

In general, the storage tank should be sized to handle to Gals/day required.In this example, we calculated a 100 Gal/day need so a 119 gallon tank would be used. If you install a recirc pump between tanks, you can use the combinedvolume of the two tanks.

A second school of thought is to have a 1:1 - 2:1 ratio between tank volume in gallons and collector area in s.f.

In our example, the tank volume is 119 gallons, the collector area is 109 s.f.

This works out to a 1.1 - 1.0 ratio.

If you added a recirc pump to an existing 60 gallon tank, the ratiowould be 1.6 - 1.0.

8 How do you size the Solar Pump?

The same rules apply for the Solar Pump as they do in any other hydronicapplication.

What are my BTU needs?What are my flow requirements?What is my pressure Drop?

Now size my pump.

EXAMPLES OF SOLAR SYSTEM COSTS WITH INCENTIVES

SYSTEM #1

$6,700.00 INSTALLED COST (Minimum required to maximize Federal & State incentives)

Federal Tax Credit = 30% of Installed Cost up to $2,000.00$2,000.00 / .30 = $6,666.66or $6,667.00 * .30 = $2,000.00

MA Tax Credit = 15% of Installed Cost up to $1,000.00$1,000.00 / .15 = $6,666.66or $6,667.00 * .15 = $1,000.00

Keyspan Rebate = 15% of Installed Cost up to $1,500.006,700.00 * .15 = $1,005.00This does not maximize Keyspan incentive!

The Federal and State incentive come in the form of TAX CREDITS. These you take off of your Taxes Owed when filling out your tax returns.The Keyespan incentive comes in the form of a direct cash REBATE. Remember, this is for Keyspan Customers only installing Solar for DHW!

A homeowner who installed a system for $6,700.00 would be able to reducetheir taxes owed by $3,000.00 in this example. This would result in a net installed cost of $3,700.00. If they are also a Keyspan Customer, the net installed cost drops to $2,695.00.

SYSTEM #2

$10,000.00 INSTALLED COST

A homeowner who installed a system for $10,000.00 would also be able to reducetheir taxes owed by $3,000.00. This would result in a net installed cost of $7,000.00. If they are also a Keyspan Customer, they would be able to maximize the Keyspan Rebate.The net installed cost in this example would drops to $5,500.00.

Solar Cost Analysis

20 * 8.34 * 60 = 10,008gals/pp/pd lbs. per gal temp. rise BTU/pp/pd

of water

5 * 10,008 = 50,040family size BTU/pp/pd BTU/day

3 * 22,000 = 66,000flat plate panel output system outputcollectors sunny day sunny day

Versus Oil1 gal/oil = 4.5 = 138,000

$ per gal BTU/hour

138,000 * 0.75 = 103,500BTU/hour efficiency BTU/gal

w/ standby oil

50,040 / 103,500 = 0.48BTU/day BTU/gal gals/pd

DHW need oil oil

0.48 * 4.5 * 365 = 794.11$ gals/pd $ per gal days gross savings

oil per year

794.11$ * 0.65 = 516.17$ gross savings Solar net savings

per year Fraction per year

Massachusetts

Residential Renewable Energy Income Tax Credit

Incentive Type: Personal Tax Credit

Eligible Renewable/OtherTechnologies:

Solar Water Heat, Solar Space Heat, Photovoltaics, Wind

Applicable Sectors: Residential

Amount: 15%

Maximum Incentive: $1,000

Carryover Provisions: Excess credit may be carried forward three years

Eligible System Size: Not specified

Equipment/InstallationRequirements:

System must be new and in compliance with all applicable performance and safety standards and must be reasonably expected to remain in operation for at least five years.

Authority 1: M.G.L. Ch. 62, § 6(d)

Date Enacted: 1979

Website: http://www.state.ma.us/doer/programs/renew/renew.htm#taxcred

Summary:

Massachusetts allows a 15% credit -- up to $1,000 -- against the state income tax for the cost of a renewable-energy system (including installation costs) installed on an individual’s primary residence. If the credit amount is greater than a resident's income tax liability, the excess credit amount may be carried forward to the next succeeding year for up to three years. Eligible technologies include solar water and space heating, photovoltaics (PV), and wind-energy systems.

The credit is available to any owner or tenant of residential property. For a newly constructed home, the credit is available to the original owner/occupant.

Contact:

Legal Department Massachusetts Division of Energy Resources (DOER)100 Cambridge St. Suite 1020 Boston, MA 02114 Phone: (617) 727-4732 Fax: (617) 727-0030 E-Mail: [email protected] site: http://www.mass.gov/doer/home.htm

Tax Information Massachusetts Department of Revenue P.O. Box 701 Boston, MA 02204 Phone: (800) 392-6089 Web site: http://www.dor.state.ma.us

Federal Incentives for Renewables and Efficiency

Printable Version Residential Solar and Fuel Cell Tax Credit

Last DSIRE Review: 01/08/2008

Incentive Type: Personal Tax Credit Eligible Renewable/Other

Technologies:Solar Water Heat, Photovoltaics, Fuel Cells, Other Solar Electric Technologies

Applicable Sectors: Residential Amount: 30%

Maximum Incentive: $2,000 for solar-electric systems and solar water-heating systems; $500 per 0.5 kW for fuel cells

Carryover Provisions: Excess credit may be carried forward to succeeding tax yearEligible System Size: Not specified

Equipment/Installation Requirements:

Solar water heating property must be certified by SRCC or by comparable entity endorsed by the state in which the system is installed. At least half the energy used to heat the dwelling's water must be from solar in order for the solar water-heating property expenditures to be eligible.

Authority 1: 26 USC § 25D Date Enacted: 8/8/2005Effective Date: 1/1/2006

Expiration Date: 12/31/2008

Summary:

Note: IRS Form 5695 & Instructions: Residential Energy Credits for Tax Year 2007 are now available. Also note that the federal tax credits for home energy-efficiency improvements under 26 USC § 25C expired on 12/31/07, but the solar and fuel cell tax credits are available through 12/31/08. The Energy Policy Act of 2005 (H.R. 6, Sec. 1335) established a 30% tax credit up to $2,000 for the purchase and installation of residential solar electric and solar water heating property. An individual can take both a 30% credit up to the $2,000 cap for a photovoltaics system and a 30% credit up to a separate $2,000 cap for a solar water heating system. A 30% tax credit up to $500 per 0.5 kilowatt (kW) is also available for fuels cells. Initially scheduled to expire at the end of 2007, the tax credits were extended through December 31, 2008, by Section 206 of the Tax Relief and Health Care Act of 2006 (H.R. 6111). Solar water heating property must be certified for performance by the Solar Rating Certification Corporation (SRCC) or a comparable entity endorsed by the government of the state in which the property is installed. Note that the tax credit does not apply to solar water heating property for swimming pools or hot tubs. The credit is calculated based on the individual’s expenditures excluding subsidized energy financing, which is defined as "financing provided under a Federal, State, or local program a principal purpose of which is to provide subsidized financing for projects designed to conserve or produce energy." Consumers who receive other incentives are advised to consult with a tax professional regarding how to calculate this federal tax credit. If the federal tax credit exceeds tax liability, the excess amount may be carried forward to the succeeding taxable year. Expenditures include labor costs for the onsite preparation, assembly, or original installation of the system and for piping or wiring to interconnect the system to the dwelling. To be eligible for the credit, a system must be "placed in service" or activated on or after January 1, 2006, and on or before December 31, 2008. Expenditures with respect to the equipment are treated as made when the installation is completed. If the installation is on a new home, the "placed in service" date is the date of occupancy by the homeowner.

Contact:

Public Information - IRS

Federal Incentives for Renewables and Efficiency

Printable Version

Business Energy Tax Credit

Last DSIRE Review: 07/25/2007

Incentive Type: Corporate Tax Credit Eligible Renewable/Other

Technologies:Solar Water Heat, Solar Space Heat, Solar Thermal Electric, Solar Thermal Process Heat, Photovoltaics, Geothermal Electric, Fuel Cells, Solar Hybrid Lighting, Direct Use Geothermal, Microturbines

Applicable Sectors: Commercial, Industrial Amount: For equipment placed in service from January 1, 2006 until December 31,

2008, the credit is 30% for solar, solar hybrid lighting, and fuel cells, and 10% for microturbines. The geothermal credit remains at 10%.

Maximum Incentive: $500 per 0.5 kW for fuel cells; $200 per kW for microturbines; no maximum specified for other technologies

Eligible System Size: Microturbines less than 2 MW; fuel cells at least 0.5 kWAuthority 1: 26 USC § 48Authority 2: IRS Form 3468 (Tax Year 2006)

Summary:The federal Energy Policy Act of 2005 (H.R. 6) expanded the federal business energy tax credit for solar and geothermal energy property to include fuel cells and microturbines installed in 2006 and 2007, and to hybrid solar lighting systems installed on or after January 1, 2006. These provisions of the tax credit were later extended through December 31, 2008, by Section 207 of the Tax Relief and Health Care Act of 2006 (H.R. 6111). (A 10% federal energy tax credit was available to businesses that invested in or purchased solar or geothermal energy property in the United States prior to January 1, 2006.)

For eligible equipment installed from January 1, 2006, through December 31, 2008, the credit is set at 30% of expenditures for solar technologies, fuel cells and solar hybrid lighting; microturbines are eligible for a 10% credit during this two-year period. For equipment installed on or after January 1, 2009, the tax credit for solar energy property and solar hybrid lighting reverts to 10% and expires for fuel cells and microturbines. The geothermal credit remains unchanged at 10%.

The credit for fuel cells is capped at $500 per 0.5 kilowatt (kW) of capacity. The maximum microturbine credit is $200 per kW of capacity. No maximum is specified for the other technologies.

Solar energy property includes equipment that uses solar energy to generate electricity, to heat or cool (or provide hot water for use in) a structure, or to provide solar process heat. Hybrid solar lighting systems are those that use solar energy to illuminate the inside of a structure using fiber-optic distributed sunlight. Geothermal energy property includes equipment used to produce, distribute, or use energy derived from a geothermal deposit. It does not include geothermal heat pumps. For electricity produced by geothermal power, equipment qualifies only up to, but not including, the electrical transmission stage. Energy property does not include public utility property, passive solar systems, or pool heating equipment.

To qualify, the original use of the equipment must begin with the taxpayer or it must be constructed by the taxpayer. The equipment must also meet any performance and quality standards in effect at the time the equipment is acquired. The energy property must be operational in the year in which the credit is first taken.

If the project is financed in whole or in part by subsidized energy financing or by tax-exempt private activity bonds, the basis on which the credit is calculated must be reduced. (The formula is described in the tax credit instructions.) Subsidized energy financing means "financing provided under a federal, state, or local program, a principal purpose of which is to provide subsidized financing for projects designed to conserve or produce energy." Therefore, a business must reduce the basis for calculating the credit by the amount of any such incentives received.

Contact: Public Information - IRS

.

Massachusetts

KeySpan Energy Delivery - Solar Thermal Rebate Program

Incentive Type: Utility Rebate Program

Eligible Renewable/OtherTechnologies:

Solar Water Heat and Solar Pool Heating for residential customers; Also, Solar Space Heat and Solar Thermal Process Heat for commercial/industrial customers

Applicable Sectors: Commercial, Industrial, Residential, Multi-Family Residential (KeySpan Customers Only)

Incentive Amount: Residential: $1,500; Commercial/Multi-family: $3/therm based on estimated first-year savings

Maximum Incentive: Residential: $1,500; Commercial/Multi-family: $100,000 per project, up to 50% of project costs

Summary:

KeySpan provides funding support to residential, commercial, industrial, and multifamily customers that install solar thermal technologies between 5/1/07 and 4/28/08. Recommended solar thermal applications include solar hot water heating, solar pool heating, and in some cases solar space heating or high temperature process applications. Eligibility requirements are in place to ensure quality installation of solar thermal systems.

Residential customers: KeySpan customers with eligible SHW systems can apply for a rebate of 15% off project costs up to a maximum of rebate of $1,500 for solar water heating systems . This rebate requires that participating customers share their water heating usage data for a period of 12 months in order to receive funding. KeySpan works directly with residential solar installers, who submit rebate application on behalf of the KeySpan customer.

Commercial & Industrial, and Multi-family customers: KeySpan requires a free energy audit to interested participants to identify appropriate solar thermal technologies as well as estimated natural gas savings. Commercial, industrial, and multifamily customers receive a one-time rebate of $3 per therm of estimated first-year savings, up to 50% of the project costs or $100,000 per project. Visit www.keyspansaves.com to get started.

Funding is limited. For further information please use the website above or contact Keyspan by e-mail.

Contact:

General Information Solar Thermal/Energy Efficiency KeySpan Energy Delivery 52 Second Ave Waltham, MA 02451 E-Mail: [email protected]

S o l a r C o l l e c t o r

SX40V

SYSTEM FILLTo heat zones

Existing DHW Tank

Solar Storage Tank

EXISTING HYDRONIC SYSTEM

Cold InHot Out

S1

S2

Fill & Purge Valve

781-721-0303 FAX 781-721-9119 WWW.CAPCOSUPPLY.COM

THIS IS ONLY A CONCEPT DRAWING. ALL CONDITIONS AND NECESSARY COMPONENTS MUST BE FIELD VERIFIED AND ARE THE RESPONSIBILITY OF THE INSTALLING CONTRACTOR

10 INDUSTRIAL PARKWAYWOBURN MA 01801

ENERGY SUPPLY, INC.C A P C O

Thermal Solar Retrofit

2.21.08NLC

S1

S2

This example shows a hydronic system heating the existing domestic hot water. The retrofit application would work with any type of DHW heater. It could be electric, oil-fired or gas-fired.

The Solar portion of work would remain the same. The Hot Out of the Solar Tank would be the Cold In on the existing tank.

Defrost AirFrom Inside

Stale air to outside

Fresh Air In From

Outside

Stale air from

inside

Warmed Air To Inside

Solar Pumping Station

SX40V

SYSTEM FILL

781-721-0303 FAX 781-721-9119 WWW.CAPCOSUPPLY.COM

THIS IS ONLY A CONCEPT DRAWING. ALL CONDITIONS AND NECESSARY COMPONENTS MUST BE FIELD VERIFIED AND ARE THE RESPONSIBILITY OF THE INSTALLING CONTRACTOR

10 INDUSTRIAL PARKWAYWOBURN MA 01801

C A P CENERGY SUPPLY, INC.

OConceptual Solar with DHW and

reheat to HRV7.02.08

NLC

CondensingWall Hung

Boiler

GASSUPPLY

Collectors

DHW Tank Solar Tank

HRV

S1S2

S1

S2

Solar Handbook

Documents

Transcript of Solar Handbook