SOLAR THERMAL WATER SOLAR THERMAL WATER HEATINGHEATING

SIMON WHELANSIMON WHELAN

TopicsTopics

Solar Thermal Water HeatingSolar Thermal Water HeatingTypes of panelsTypes of panels

Flat platesFlat platesVacuum tubesVacuum tubes

CylindersCylindersCost/PaybackCost/Payback

Solar Water Heating- uses

• Domestic water heating- High grade heat from the sun- Mostly showers and washing

- Dishwashers, washing machine often heated separately – need direct hot feed appliances

• Space Heating Support- Large capital and material investment

- Most energy in Summer when needed least

- Better bang for heating buck in insulation and design

Water heating - % of your energy use

How do solar panels work3 energy flows - heat collection, heat loss, heat transfer

Domestic Solar Water Heating

•A. Solar panels

•B. Pump Station

•C. Cylinder

•D. Boiler

4 main things to consider

•1.Orientation - South is best, - Anywhere between SW – SE OK- East West requires specific system

•2. Occupancy = Water Usage =Size of Cylinder

- 50 L of hot water per person a day

•3. Type of Panel – Flat Plate or evacuated tube

•4. Size of Array

Two main Types of Panel;Two main Types of Panel;• Flat plate panelsFlat plate panels

-In Roof-In Roof-On Roof-On Roof

• Vacuum tube Vacuum tube -direct contact water heating-direct contact water heating-Single-walled vacuum tube with heat pipes-Single-walled vacuum tube with heat pipes-Twin-walled vacuum tube with heat pipe-Twin-walled vacuum tube with heat pipe

Flat Panel – In roof - GalwayFlat Panel – In roof - Galway

Flat Panel – In roof - Flat Panel – In roof - CelbridgeCelbridge

•Flashing to weather proofFlashing to weather proof

•Very Similar to Velux WindowsVery Similar to Velux Windows

Flat Panel – In roof - Flat Panel – In roof - CelbridgeCelbridge•Install roof covering (slates/Tiles) around flashingInstall roof covering (slates/Tiles) around flashing

•No wind load issuesNo wind load issues

•Pipework runs directly in to the attic space – no roof Pipework runs directly in to the attic space – no roof penetration issuespenetration issues

Flat Panel – on roof Flat Panel – on roof 2 fixing options2 fixing options- Bolts – Slate roof- Bolts – Slate roof- Bracket – Tile roof- Bracket – Tile roof

Flat Panel – on roof - Flat Panel – on roof - DelganyDelgany

Use of brackets on Use of brackets on tile rooftile roof

Alumium Profile to Alumium Profile to support panelssupport panels

Advantages of Flat Advantages of Flat platesplates

•Durable option – long life time 25 -35 years

•Better Aesthetics – great looking panel flashed into roof

•Can take up less surface area on roof than evacuated tubes

Vaccuum tubes: BrayVaccuum tubes: Bray

Vaccuum tubes –Heat pipes

Multiple panels in in Bray- Multiple panels in in Bray- straight connection.straight connection.

Frame on roof contains tubes – Frame on roof contains tubes –

mutiple panels in seriesmutiple panels in series

Flat roof:Flat roof:

Watch the wind load

Ground mount:Ground mount:

Long Pipe Run – inefficiencies Long Pipe Run – inefficiencies introducedintroduced

ADVANTAGES OF TUBESADVANTAGES OF TUBES• Typically more efficient than FP per mTypically more efficient than FP per m22 of of

ApertureAperture area area

– Totally insulated – no heat lossTotally insulated – no heat loss– Passively tracking – Incident Angle ModifierPassively tracking – Incident Angle Modifier– Lower thermal massLower thermal mass

• Lighter to lift into placeLighter to lift into place• Sit on top of slates – easier to retrofitSit on top of slates – easier to retrofit• Double wall vacuum tubes are potentially a very Double wall vacuum tubes are potentially a very

sustainable product in Ireland.sustainable product in Ireland.

DISADVANTAGESDISADVANTAGES• AestheticsAesthetics• Maintenance required after 15 to 20 yrs but Maintenance required after 15 to 20 yrs but

modularmodular

Pump station installationPump station installation•Attic installationAttic installationController in accessible Controller in accessible positionpositionExpansion Vessel installed Expansion Vessel installed below pipe linebelow pipe lineBlow off vessel Blow off vessel 3 port valve (HT) to heat 3 port valve (HT) to heat dumpdumpNeed power point – fused Need power point – fused circuit in area.circuit in area.

Solar Controller: Resol BS3Solar Controller: Resol BS3

• Temperature displaysTemperature displays

• Controls PumpControls Pump

• Frost-protectionFrost-protection

• Store temperature Store temperature limitationlimitation

• Excess heat dissipation to Excess heat dissipation to radiator or can be after radiator or can be after heat functionheat function

Solar CylindersSolar CylindersDual/Triple coil CylindersDual/Triple coil Cylinders– Tall = better stratificationTall = better stratification– Insulation thickness 50mm minInsulation thickness 50mm min– Copper or Stainless steelCopper or Stainless steel– High efficiency solar coil - 20% High efficiency solar coil - 20%

of panel surface areaof panel surface area– Two sensor ports for controller Two sensor ports for controller

temperature probestemperature probes– Consider weight of larger Consider weight of larger

cylinder!cylinder!

Choosing a System – Look for Energy yield not Efficiency

• Sun is a moving energy source.

• Panels differ

• Zero loss efficiency describes efficiency at normal incidence - Noon

• Not sufficient to describe performance accurately.

Choosing a System – Look for Energy yield not Efficiency

• Incident Angle Modifier• Energy yield of system• Not efficiency of panel• TSol/DEAP/Test results• Establish Cost/Benefit

Costs and Payback How long is Costs and Payback How long is a piece of string?a piece of string?• Typical cost range from E4500 – E5500 Typical cost range from E4500 – E5500

installedinstalled• Grant aid brings cost to 3500 – 4000Grant aid brings cost to 3500 – 4000• Change in subsidy structure is forecastChange in subsidy structure is forecast• Many variables:Many variables:level of water use level of water use

Cost/type of primary heatingCost/type of primary heatingDurability of solar system – Durability of solar system –

long termlong termFuture energy costsFuture energy costs

• At today’s prices solar can contribute approx At today’s prices solar can contribute approx Euro200 – 300 per annum.Euro200 – 300 per annum.

• Hartwick Rule: Invest profits from natural Hartwick Rule: Invest profits from natural resource use in technological replacementsresource use in technological replacements

Commercial Installations:Commercial Installations:Hotels/B&B’S – Hotels/B&B’S – solar makes a lot of solar makes a lot of

sensesenseOld Rectory Kinsale:Old Rectory Kinsale:

Tesco – large daytime Tesco – large daytime occupancy: occupancy:

• Further information:Further information:

• info@ecologics.ie

•www.ecologics.ie

Thank You!Thank You!