© Trane 200810/11/2014 1 The Latest in High Performance, Hot and Humid Climate, HVAC Systems Art...

© Trane 200804/11/23 1

The Latest in High Performance, Hot and Humid Climate, HVAC Systems

Art Hallstrom, P.E., ASHRAE FellowDan PollockTrane System Specialists

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ASHRAE’s New HQ Renovation

Located in Atlanta, Ga. Hot and Humid Climate

A “near net” zero designA “near net” zero designA living lab to advance the A living lab to advance the state of the artstate of the art

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Today’s presentation

Project Goals – IEQ, EUI, Standards to follow

•Envelope and Mechanical Systems Design•Ventilation System and the DOAS Unit

– Energy Wheel– CDQ Wheel– Direct Drive Plenum Fans– DX Coil/Compressors

•DOAS Unit System Comparisons•DOAS Unit Control •Questions

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ASHRAE HQ Renovation

Who – ASHRAE Society, their HQ

Where – Atlanta, Ga. NE, near I-85

What – Total building upgrade and energy retrofit. 2 story office building, 30,000 sq ft. Expanded by a new training center

Why – Become a living lab to allow researchers to find out how to get to net zero energy design without impacting IAQ

When – Construction June 2007-June 2008

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Challenges of very low energy use buildings

Will it have a Sustainable or Green focus?Sustainable is indoor environment and energyGreen includes a whole lot more

What metrics to measure? Comfort and health. Also need metrics to evaluate performance. IEQ for comfort, EUI for energy.

What EUI energy metric will be used? Site, Design, or Source EUI

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EUI – Energy Use Index

BTUH/Net conditioned sq ft. – yearly averageHas several definitions

Site EUI is the power coming into the building. Allows evaluation of existing building performance. Easy to obtain.

Design or ASHRAE 90.1 EUI - For new buildings, design only, No plug or process loads. Nearly impossible to measure after the fact.

Source EUI – Building power use at the power plant. Generally nation wide plant efficiencies are used to source number. Source EUI often relates to CO2 impact of the building.

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EUI varies by building type

Design EUI Site EUI

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ASHRAE wanted their HQ building to meet all relevant ASHRAE Standards

ASHRAE Standard 90.1-2004 (energy efficiency)

ASHRAE Standard 55-2004 (thermal comfort)

ASHRAE Standard 62.1-2004 (ventilation)

ASHRAE Standard 100-2006 (energy in existing buildings)

ASHRAE Guideline 0-2005 (commissioning)

ASHRAE Guideline 1-2006 (HVAC&R system commissioning)

USGBC LEED® Rating System EB Version 2.0

USGBC LEED®-NC Rating System 2.2

Applicable local, state and national building codes

ASHRAE Standard 15 (refrigerant safety)

ASHRAE Standard 189 (Green) – proposed (portions of)

ASHRAE Advanced Energy Design Guide (offices)

US EPA Energy Star

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The Building

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• Envelope upgrade – cool white reflective roof membrane

• New Lighting• Low flow fixtures, etc. for 46% reduction in

water use• PV arrays on roof

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• New Mechanical System:

Replaced old VAV reheat rooftop with:

– Common dedicated outside air system (DOAS) with Split System Rooftop with energy recovery wheel, series desiccant dehumidification wheel, electrostatic enhanced filters and DX air-cooled R410 multi-stage compressor/condensers

– First floor: air-cooled variable refrigerant flow fan coil units with inverter-driven heat pumps

– Second floor: 13 ground-source direct expansion heat pumps serviced by 12 wells

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Mechanical System Layout

WSHP Filter/vav

VRF Filter/vav

OA

EA

OA

EA

OA

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DOAS Unit

DOAS Unit

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DOAS Unit

DOAS Unit

Occupied mode

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DOAS Unit

DOAS Unit

Unoccupied mode

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ASHRAE HQ DOAS Unit

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6 step/30 ton R410 Compressor Split

Set up for VAV Outside Air

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Energy Saving System Strategy

DOAS Unit will provide Cool, Dry, Filtered Outside Air. 1. Humidity actively controlled to 44 dewpoint at all

times by a series desiccant wheel and cooling coil. It can boost water removal when needed.

2. OA CFM delivered to space based on CO23. Building pressure controlled with central exhaust fan

Room units will do sensible temperature control. 2 and 3 speed fans match sensible load.

This control strategy is very simple, easy to manage.

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Before going further, what is the predicted EUI?

Old building –

Site 76,900 Btuh/Sq ft-year

Renovation

Site 42,628 Btuh/Sq ft-year

10% larger building–

adjusted to same size gives a

~49.9% energy reduction

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The Dedicated Outside Air Unit

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Energy (Enthalpy) Wheel

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4A Energy Wheel

ARI 1060 certified

Has bypass dampers

78% total effectiveness

Rotates at 20 rpm

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Energy Wheel - Modes of Operation

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CDQ Desiccant Wheel

When rotating, lowers leaving dewpoint

wa

ter

va

po

r

C ondensate

EnteringAir

LeavingAir

CDQ desiccant wheel

Cooling coil

Fan Leaving RegenerationAir

Leaving CoolingCoil Air

Process Components

Entering Air Leaving Regeneration

Leaving Cooling Coil

Leaving Air

Condensation

adsorption

regeneration

Stage of Process

Hum

idity

Lev

el

Humidity During The CDQ Process

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CDQ Wheel uses Type 3 Desiccant

ability tohold water

vapor

high

relative humidity, %

low

0 60 1004020 80

typicalLeaving

coilcondition

typicalentering

aircondition

Transfers water from high RH to low RH air

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Medium Size Wheel

Series Desiccant Wheel

Has bypass dampers

Rotates at 8 RPH

© Trane 2008

Saves energy 3 ways over cool reheat

(2) Reheat Capacity

11030 40 50 60 70 80 10090

dry-bulb temperature, °F

80

70

50

4030

wet-b

ulb

tem

pera

ture

, °F

60

180

160

140

120

100

80

60

40

20

hum

idity

ratio

, gra

ins/lb

of d

ry a

ir

peak DPOApeak DPOA

SASA

RARA

(1) Air side savings

(3) Colder Coil

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© Trane 2008

Controlling the system

• DOAS takes care of all the latent load, maintains a constant dew point

• Humidity can be controlled independently of temperature, not humid at part load

• Control off of space or common return humidity

• Space units handle sensible energy, little need to add reheat

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Seven Unique EW/CDQ Control Areas

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OA Bins – DOAS Performance

Units: I-P 13874 ATLANTA N 33 39 W 84 26 1033.515 ft ASHRAE HQ -BIN Analysis for DOAS Unit Saved

Date: Oct 19,2006# hrs: 3744 Recovered vs ReheatGiven Data Control Energy SA SA Net Net Gross Tons TonsOUTSIDE AIR ASSUMED RETURN AIR Mode Wheel DB W Lat Sens SHR Total Total Total

Bin # Hrs W, gr/lb DB (F) h (BTU/lb) W, gr/lb DB (F) h (BTU/lb) Status F gr/lbm Tons Tons Tons Saved1 1 147.5 84 43.3 65 75 27 1 ON 55 44 16.7 13.3 0.443 31.8 22.2 26.82 2 142.5 82.9 42.3 65 75 27 1 ON 55 44 16.1 13.1 0.449 31.0 20.6 25.23 10 137.5 82.7 41.4 65 75 27 1 ON 55 44 13.0 15.6 0.545 30.4 19.4 24.04 5 132.5 85 41.2 65 75 27 1 ON 55 44 15.0 13.1 0.466 29.9 19.2 24.05 18 127.5 84.4 40.3 65 75 27 1 ON 55 44 14.4 12.9 0.473 29.2 17.8 22.66 29 122.5 82 38.9 65 75 27 1 ON 55 44 13.9 12.9 0.481 28.3 15.8 20.47 91 117.5 81.3 37.9 65 75 27 1 ON 55 44 13.3 12.3 0.480 25.6 14.4 19.08 187 112.5 79.5 36.7 65 75 27 1 ON 55 44 12.7 12.0 0.486 26.6 12.5 17.29 144 107.5 76.8 35.3 65 75 27 1 ON 55 44 12.2 11.6 0.487 25.6 10.3 14.9

10 171 102.5 76.3 34.3 65 75 27 1 ON 55 44 11.6 11.4 0.496 24.8 9.0 13.611 209 97.5 73.8 33 65 75 27 1 ON 55 44 11.0 11.0 0.500 23.8 6.9 11.412 105 92.5 73.8 32.2 65 75 27 1 ON 55 44 10.4 10.9 0.512 23.1 5.7 10.313 184 87.5 72.8 31.1 65 75 27 1 ON 55 44 9.9 10.7 0.519 22.3 4.2 8.814 159 82.5 70.4 29.8 65 75 27 1 ON 56 44 9.3 10.3 0.526 21.4 2.2 6.715 125 77.5 71 29.1 65 75 27 1 ON 56 44 8.7 10.2 0.540 20.7 1.3 5.916 173 72.5 68.4 27.7 65 75 27 2 ON 56 44 8.2 9.8 0.544 19.7 -0.8 3.717 175 67.5 66.8 26.6 65 75 27 2 ON 56 44 7.6 9.5 0.556 18.6 -2.6 1.918 151 62.5 64.9 25.3 65 75 27 4 OFF 54 44 6.5 6.4 0.496 14.6 0.0 3.419 164 57.5 61.6 23.7 65 75 27 4 OFF 54 44 4.7 4.7 0.500 11.1 0.0 3.320 110 52.5 61.6 23 65 75 27 4 OFF 55 44 3.1 4.0 0.563 8.8 0.0 4.021 154 47.5 58.6 21.4 65 75 27 4 OFF 55 44 1.3 2.2 0.629 5.2 0.0 4.122 173 42.5 54.9 19.8 65 75 27 5 OFF 58 43 0 -1.891667 1.000 0 -1.891667 -1.89166723 168 37.5 52.3 18.4 65 75 27 5 Modulate 60 44 0.0 -4.716667 1.000 0 -4.833333 -4.83333324 166 32.5 50.8 17.2 65 75 27 5 Modulate 61 43 0.0 -5.825 1.000 0 -7.166667 -7.16666725 227 27.5 46.9 15.5 65 75 27 5 Modulate 61 43 0.0 -7.75 1.000 0 -10.83333 -10.8333326 226 22.5 43.8 14 65 75 27 5 Modulate 63 44 0 -10.16667 1.000 0 -15.5 -15.527 192 17.5 42.8 13 65 75 27 5 Modulate 64 44 0.0 -11.33333 1.000 0 -18.41667 -18.4166728 150 12.5 33.6 10 65 75 27 5 Modulate 61 44 0.0 -14.91667 1.000 0 -23.5 -23.529 75 7.5 23.6 6.8 65 75 27 5 Modulate 59 44 0 -19 1.000 0 -29.25 -29.25

3744

Target SA Condtions 55F 44Gr /lbm Modes 1-4Target SA Condition 65F Mode 5

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Direct Drive Plenum Fans

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Direct Drive Plenum Fan ‘Rules’

• Adjust fan wheel width, diameter and speed for optimal peak efficiency

• Every fan gets a VFD, not a starter• VFD and fan motors can operate above motor

synchronous speed (e.g. 1800 rpm motors can operate safely up to 2700 rpm)

• Quiet units have a smaller cost premium• Standard air handlers can be designed with dual

supply fans to reduce unit length

New Fan Selection Rules

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Direct Drive Fan Selection at Peak Fan and Motor Efficiency

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BHP Comparison with Standard Fans

Supply Fan - 6513 CFM, 6.22 SP Peak

Fan size and type BHPWheel Speed

hp rpm

17B - 18.25" FC 12.48 1465

F17 - 18" AF Housed 10.57 2346

Y17 - 22.25" AF Direct Drive 10.02 2027

17P - 24" AF Belt Drive 10.78 1940

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Piezometer Ring

•Measures fan CFM•Built into fan inlet cone•No impact on energy•No impact on noise•Very accurate•Order with air handler

Inexpensive and Accurate

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Controls Summary

Building:DOAS unit controls the building humidity at 44 dewpoint. Room units control sensible temperature and have dry

coils. Dry Coils reduces potential for IAQ problems and is more energy efficient.

DOAS Unit:Space humidity above dewpoint set point, series wheel

is on. Space below dewpoint set point, series wheel is off and

coil LAT adjusted to minimize system fighting.

Optimized Independent Humidity Control

© Trane 2008

High performance buildings

Need a total design approachArch – Engineer – Owner – CM - ContractorsAll $ decisions need to be evaluated – envelope, mechanical, green ideas (parking lot dirt)

Use total building energy modeling Separate the OA and recirculated airControl humidity from a central point Use airside energy recoveryMeasure building IEQ and EUI

© Trane 2008

System Comparisons

How does the energy wheel and CDQ wheel enhance the cold coil in the ASHRAE HQ DOAS system.

– Target: 44 LAT – Atlanta, Ga. Weather– Air cooled dx R410 compressors

1.Cold Coil – Compressor (10.5 EER)

2.Add energy wheel (13 EER, 80% Recovery)

3.Add both wheels (13 EER, 80%, Std CDQ)

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© Trane 2008

Cold Coil Approach

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Compressor, Air Cooled Condenser, Supply FanCompressorCompFan

ARI EER KW/TON KW/Ton Fan KW10.5 1.063857 0.079

Coil Evap Temp 44 3.8

Refrig DOAS 100cfm/ton unitOA DB HRS ton-hours Evap Adj Amb Adj KW/Ton KWh Fan Kwh

84 1 58.6 1.195 0.857 1.396372 81.82739 3.882.9 2 112.4 1.195 0.8427 1.374647 154.5103 7.682.7 10 544 1.195 0.8401 1.370697 745.6593 38

85 5 269.5 1.195 0.87 1.416122 381.6448 1984.4 18 932.4 1.195 0.8622 1.404272 1309.343 68.4

82 29 1412.3 1.195 0.831 1.356872 1916.311 110.281.3 91 4058.6 1.195 0.8219 1.343047 5450.892 345.879.5 187 8190.6 1.195 0.7985 1.307498 10709.19 710.676.8 144 5832 1.195 0.7634 1.254173 7314.339 547.276.3 171 6566.4 1.195 0.7569 1.244299 8170.562 649.873.8 209 7356.8 1.195 0.7244 1.194924 8790.817 794.273.8 105 3507 1.195 0.7244 1.194924 4190.599 39972.8 184 5722.4 1.195 0.7114 1.175174 6724.817 699.270.4 159 4467.9 1.195 0.6802 1.127775 5038.785 604.2

71 125 3325 1.195 0.688 1.139625 3789.252 47568.4 173 4048.2 1.195 0.6542 1.088275 4405.556 657.466.8 175 3587.5 1.195 0.6334 1.056676 3790.823 66564.9 151 2718 1.195 0.6087 1.019151 2770.052 573.861.6 164 2361.6 1.195 0.5658 0.953977 2252.911 623.261.6 110 1408 1.195 0.5658 0.953977 1343.199 41858.6 154 1432.2 1.195 0.5268 0.894727 1281.428 585.2

80,613 8,995 89,607

© Trane 2008

Cold Coil with Energy Wheel

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Includes Compressor, Air Cooled Condenser, Supply Fan, Energy WheelCompressorCompFan

ARI EER KW/TON KW/Ton Fan KW13 0.844077 0.079 6

Coil Evap Temp 44 4.5

EW Only Condenser PowerOA DB HRS ton-hours Evap Adj Amb Adj KW/Ton KWh Fan Kwh

84 1 36.4 1.195 0.857 1.127401 41.0374 682.9 2 71.2 1.195 0.8427 1.1101644 79.0437 1282.7 10 350 1.195 0.8401 1.1070304 387.4606 60

85 5 173.5 1.195 0.87 1.1430708 198.3228 3084.4 18 612 1.195 0.8622 1.1336689 693.8054 108

82 29 954.1 1.195 0.831 1.0960616 1045.752 17481.3 91 2748.2 1.195 0.8219 1.0850928 2982.052 54679.5 187 5853.1 1.195 0.7985 1.0568873 6186.067 112276.8 144 4348.8 1.195 0.7634 1.0145791 4412.201 86476.3 171 5027.4 1.195 0.7569 1.0067442 5061.306 102673.8 209 5914.7 1.195 0.7244 0.9675699 5722.886 125473.8 105 2908.5 1.195 0.7244 0.9675699 2814.177 63072.8 184 4949.6 1.195 0.7114 0.9519002 4711.525 110470.4 159 4118.1 1.195 0.6802 0.9142929 3765.149 954

71 125 3162.5 1.195 0.688 0.9236947 2921.185 75068.4 173 4192.367 1.195 0.6542 0.8829534 3701.665 103866.8 175 4039.583 1.195 0.6334 0.8578819 3465.485 105064.9 151 2718 1.195 0.6087 0.8281094 2250.801 679.561.6 164 2361.6 1.195 0.5658 0.7763994 1833.545 73861.6 110 1408 1.195 0.5658 0.7763994 1093.17 49558.6 154 1432.2 1.195 0.5268 0.7293902 1044.633 693

54,411 13,334 0.30 67,745

© Trane 2008

Cold Coil with CDQ and Energy Wheel

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Includes Compressor, Air Cooled Condenser, Supply Fan, Energy Wheel, Series Desiccant Wheel

CompressorCompFan FanARI EER KW/TON KW/Ton FanKW

13 0.844077 0.079 9 7.6Coil Evap Temp 50.5 6.1

CDQ Condenser Power CondOA DB HRS ton-hours Evap Adj Amb Adj KW/Ton KWh Fan Kwh

84 1 31.8 1.0975 0.857 0.958011 30.46475 7.682.9 2 62 1.0975 0.8427 0.943472 58.49527 15.282.7 10 304 1.0975 0.8401 0.940829 286.0119 76

85 5 149.5 1.0975 0.87 0.971228 145.1986 3884.4 18 525.6 1.0975 0.8622 0.963298 506.3093 136.8

82 29 820.7 1.0975 0.831 0.931577 764.5451 220.481.3 91 2329.6 1.0975 0.8219 0.922325 2148.648 691.679.5 187 4974.2 1.0975 0.7985 0.898534 4469.489 1421.276.8 144 3686.4 1.0975 0.7634 0.862848 3180.804 1094.476.3 171 4240.8 1.0975 0.7569 0.85624 3631.141 1299.673.8 209 4974.2 1.0975 0.7244 0.823197 4094.747 1588.473.8 105 2425.5 1.0975 0.7244 0.823197 1996.664 79872.8 184 4103.2 1.0975 0.7114 0.80998 3323.51 1398.470.4 159 3402.6 1.0975 0.6802 0.778259 2648.104 1208.4

71 125 2587.5 1.0975 0.688 0.786189 2034.265 95068.4 173 3408.1 1.0975 0.6542 0.751825 2562.295 1314.866.8 175 3255 1.0975 0.6334 0.730678 2378.356 133064.9 151 2204.6 1.0975 0.6087 0.705565 1555.489 921.161.6 164 1820.4 1.0975 0.5658 0.661949 1205.012 1000.461.6 110 968 1.0975 0.5658 0.661949 640.7667 67158.6 154 800.8 1.0975 0.5268 0.622298 498.3362 939.4

= 38,159 17,121 55,279

© Trane 2008

Energy savings of new components are significant

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Old Cool Reheat

13 EER and Energy Wheel Add on

13 EER, Energy and Dehumidification wheels add on

Cooling Fan Cooling Fan Cooling Fan

Hourly Average KWH

80,613

8,995

54,411

13,334

38,159

17,121

89,607

67,745

55,279

Cooling Energy savings over old Low CFM/Ton Mech Dehumidifier

Savings related to Energy Wheel +9% for 24%

Savings related to Series Desiccant Wheel +14% for 38%

Savings related to 13 EER Compressor 15%

© Trane 2008

Summary

• There are lots of ways to control temperature and humidity. Green buildings need lower shr systems. Control humidity at full AND part load.

• Look at life costs when design and operating the system

• Measure building performance on an ongoing basis

• For sustainable and maintainable operation, keep the design and controls simple.

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© Trane 200810/11/2014 1 The Latest in High Performance, Hot and Humid Climate, HVAC Systems Art...

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