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Solar Water Heating Basics

Solar Water Heating Basics. Progress Energy Florida Solar Water Heater Incentive Program Colleen Kettles Florida Solar Energy Research & Education Foundation (FlaSEREF). Solar Water Heating Basics. How It Works How Much Energy It Saves How It Helps the Environment How To Purchase

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Solar Water Heating Basics

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  1. Solar Water Heating Basics Progress Energy Florida Solar Water Heater Incentive Program Colleen Kettles Florida Solar Energy Research & Education Foundation (FlaSEREF)

  2. Solar Water Heating Basics • How It Works • How Much Energy It Saves • How It Helps the Environment • How To Purchase • How Much It Costs • What Incentives Are Available

  3. Types of Systems “Active” System • Direct Pumped • Water is the collector fluid • Freeze protection provided by drain-back tank or freeze valves • Indirect Pumped • Anti-freeze is the collector fluid • Heat exchanger utilized within storage tank

  4. Active Solar Water Heater

  5. Active Solar Water HeaterDirect Pumped

  6. Active Solar Water HeaterDirect PV Pumped

  7. Active Solar Water HeaterIndirect Pumped

  8. The Collector Active Systems • Use “flat-plate” collector • Insulated box with ½” copper piping integrated into a black absorber and glass cover • Fluid is water or anti-freeze • Designed to reach temperatures as high as 160° F

  9. The Storage Tank Active System • Specially designed, heavily insulated tank (R value of 16 or greater) • Sizes range from 52 to 120 gallons for residential applications • Has only a top electric element • In a system using antifreeze, the tank will have an internal heat exchanger

  10. Balance of System Components Active System • Pump (ac or dc) • Differential Controller, or • Photovoltaic Panel • Assorted valves and vents • Copper Piping • Insulation

  11. Types of Systems “Passive” System • Integral Collector Storage • Collector provides additional water storage • No moving parts

  12. Passive Solar Water HeaterIntegral Collector Storage

  13. Passive Solar Water HeaterIntegral Collector Storage

  14. The Collector Integral Collector Storage (ICS) • The collector is also the storage medium • Insulated box with 4” copper tubing welded together to serve as the absorber • Glass cover • Fluid is water • Designed to reach temperatures as high as 160° F

  15. The Storage Tank Integral Collector Storage (ICS) • Collector provides ½ of the storage (32-50 gallons) • Existing or conventional tank provides the balance of storage

  16. Balance of System Components ICS System • Assorted valves and vents • Anti-scald valve (optional) • Copper piping • Insulation

  17. Types of Systems “Passive System” • Thermosiphon • Tank is roof mounted above collector • Uses flat plate collector • No moving parts • Reminiscent of early solar systems

  18. Early Thermosiphon Solar Water Heater

  19. Thermosiphon System

  20. Passive Solar Water HeaterThermosiphon System

  21. The Collector Thermosiphon System • Uses “flat-plate” collector • Insulated box with ½” copper piping integrated into a black absorber and glass cover • Fluid is water or anti-freeze • Designed to reach temperatures as high as 160° F

  22. The Storage Tank Thermosiphon System • The storage tank is specially designed to be mounted on the roof above the collector • An auxiliary tank with electric element is installed in the home

  23. Balance of System Components Thermosiphon System • Assorted vents and valves • Copper piping • Insulation

  24. Household Hot Water Use • 15% – 20% of total household energy consumption • Daily usage is 20 gallons each per day for the first two occupants; 15 gallons per day for each additional occupant • Example: Four person household will use 70 gallons of hot water and will need 80 gallons of storage

  25. Collector BTU Ratings/Solar Fraction • Central Florida ambient water temperature is 72 degrees • Solar fraction is the proportion of hot water provided by the solar system • Optimal solar fraction is 70% and is based upon annual performance

  26. Collector Btu Ratings/Solar Fraction • 38,000 Btus will be needed to raise 80 gallons of cold water to 122 degrees • A 32 square foot ICS system is rated at 28,700 Btu/day and will provide a 77% solar fraction • A 40 square foot active collector is rated at 34,400 Btu/day and will provide a 92% solar fraction

  27. Savings The kWh equivalent of 38,000 Btu/day is 11.13 kWh per day x 365 days = 4,063 kWh/year (electric load) • A solar fraction of 70 will offset 2,844 kWh • A solar fraction of 77 (28,700 Btu/day) = 8.4 kWh/day x 365 days, saves (or produces) 3,066 kWh/year • A solar fraction of 92 (34,400 Btu/day) = 10 kWh/day x 365 days, saves (or produces) 3,650 kWh/year

  28. Savings At an average residential rate of $.115 per kWh: • A solar fraction of 70 will save $325/year • A solar fraction of 77 will save $350/year • A solar fraction of 92 will save $420/year

  29. Back-up Hot Water • All solar water heaters will have a conventional energy back-up • No consumer action is required to activate the back-up • Back-up is needed for periods of excessive hot water use or inadequate solar resource

  30. How It Helps the Environment • Emission Reductions (One Solar Water Heater Saves Annually) • Carbon Dioxide (5,000 lb) • Sulfur Dioxide (20 lb) • Nitrogen Oxide (12 lb) • Renewable Energy Credits • The “environmental attributes” of solar energy are a commodity

  31. How to Purchase • Contact reputable solar companies • www.flaseia.org • www.findsolar.com • Verify contractor licenses www.myfloridalicense.com Voice: 850-487-1395 • Solar contractor (CV) • Specialty solar (CW) • Plumbing contractor (CF) • Local solar license (RX)

  32. How to Purchase • Get more than one estimate, and get them in writing • Avoid high pressure sales tactics • Compare system types, sizes, prices and warranties • Ask for FSEC system certification • Ask for local references

  33. How to Purchase • A local building permit should be obtained prior to installation (although some jurisdictions no longer require) • Contractor, not the homeowner, is responsible for the permit • If in doubt, homeowner should contact the local building department • Deed restricted communities will typically require prior approval (which cannot be denied)

  34. How Much It Costs • Cost of a system varies depending upon the type of system and the size of system • Prices range from $3,000 to $5,000 in general • Rising material costs and the cost of doing business (gasoline, insurance, etc.) have resulted in price increases

  35. Financial Incentives • Incentives are designed to lower the cost to the consumer • Sales Tax Exemption (6-7%) • Florida Solar Rebate ($500) • Progress Energy Rebate ($450) • Federal Tax Credit (30% with cap of $2,000)

  36. Interaction of Incentives • Rebates should be deducted from the cost of the system before the federal tax credit is calculated • IRS has not issued regulations under this tax credit law • Exception would be if rebates are included as gross income

  37. Interaction of Incentives Example – System cost: $4,000 State rebate: - $500 PEF rebate: - $450 Actual cost: $3,050 Federal tax credit: (.30 x 3,050) = $915 Net system cost: $2,135

  38. Impact of Incentives on Consumer Savings Net System Price of $2,135 • Annual Savings of $325 = 6.5 year payback • Annual Savings of $350 = 6.1 year payback • Annual Savings of $420 = 5 year payback

  39. For More Information • www.flaseref.org • www.flaseia.org • www.fsec.ucf.edu • www.floridaenergy.org • 800-59SOLAR THANK YOU

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