2 Solar Thermal Water Heating TopicsSolar Thermal Water HeatingTypes of panelsFlat platesVacuum tubesCylindersCost/Payback
3 Solar Water Heating- uses Domestic water heating- High grade heat from the sun- Mostly showers and washingDishwashers, washing machine often heated separately – need direct hot feed appliancesSpace Heating SupportLarge capital and material investmentMost energy in Summer when needed leastBetter bang for heating buck in insulation and design
5 How do solar panels work 3 energy flows - heat collection, heat loss, heat transfer
6 Domestic Solar Water Heating A. Solar panelsB. Pump StationC. CylinderD. Boiler
7 4 main things to consider 1.OrientationSouth is best,Anywhere between SW – SE OKEast West requires specific system2. Occupancy = Water Usage =Size of CylinderL of hot water per person a day3. Type of Panel – Flat Plate or evacuated tube4. Size of Array
8 Two main Types of Panel; Flat plate panels-In Roof-On RoofVacuum tube-direct contact water heating-Single-walled vacuum tube with heat pipes-Twin-walled vacuum tube with heat pipe
19 Ground mount:Long Pipe Run – inefficiencies introduced19
20 Typically more efficient than FP per m2 of Aperture area ADVANTAGES OF TUBESTypically more efficient than FP per m2 of Aperture areaTotally insulated – no heat lossPassively tracking – Incident Angle ModifierLower thermal massLighter to lift into placeSit on top of slates – easier to retrofitDouble wall vacuum tubes are potentially a very sustainable product in Ireland.DISADVANTAGESAestheticsMaintenance required after 15 to 20 yrs but modular
21 Pump station installation Attic installation Controller in accessible position Expansion Vessel installed below pipe line Blow off vessel 3 port valve (HT) to heat dump Need power point – fused circuit in area.21
22 Solar Controller: Resol BS3 Temperature displaysControls PumpFrost-protectionStore temperature limitationExcess heat dissipation to radiator or can be after heat function22
23 Solar Cylinders Dual/Triple coil Cylinders Tall = better stratificationInsulation thickness 50mm minCopper or Stainless steelHigh efficiency solar coil - 20% of panel surface areaTwo sensor ports for controller temperature probesConsider weight of larger cylinder!
24 Choosing a System – Look for Energy yield not Efficiency Sun is a moving energy source.Panels differZero loss efficiency describes efficiency at normal incidence - NoonNot sufficient to describe performance accurately.
25 Choosing a System – Look for Energy yield not Efficiency Incident Angle ModifierEnergy yield of systemNot efficiency of panelTSol/DEAP/Test resultsEstablish Cost/Benefit
26 Costs and Payback How long is a piece of string? Typical cost range from E4500 – E5500 installedGrant aid brings cost to 3500 – 4000Change in subsidy structure is forecastMany variables: level of water useCost/type of primary heatingDurability of solar system – long termFuture energy costsAt today’s prices solar can contribute approx Euro200 – 300 per annum.Hartwick Rule: Invest profits from natural resource use in technological replacements26
27 Commercial Installations: Hotels/B&B’S – solar makes a lot of sense Old Rectory Kinsale: