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Frequently Asked Questions about solar water heaters

Q   What is a Solar Hot Water System?
A A system which turns cold water into hot water with the help of heat contained in the Sun's rays is called a solar water heating systems (SHWS)
Q  What is possible max. temperature of water  that can be attained in the solar water heating system?
A Around 60o to 90o C. The rise in temperature depends on

  • Solar Radiation

  • Weather Conditions

  • Solar collectors' system efficiency.
Q  Can it be installed anywhere?
A

Yes, it can be installed on Rooftops,  Building terrace,  Open ground

There should be : - No shading, - South orientation of the collectors, - Collector Tilt = Latitude or + 10o thereof , - Over head tank  with its bottom water outlet at least 8" above the hot water tank of a solar water heating system.
Q  Does it generate hot water on all days and in all seasons of the year?
A

It generates hot water on : -Clear sunny day (Max.), - Partially cloudy day: Moderate,

- Rainy or heavily overcast day -Nil, - Average 300 days in a year  (330 days in Gujarat & Rajasthan)
Q  Can we use any type of water such as municipality treated water, bore well water or tank water?
A Only soft and potable water recommended - Hard water can reduce efficiency over time & damages collectors
Q  What should be the type of material to be used for hot storage tanks?
A Stainless Steel  or copper for small tanks, Mild steel tank with anti-corrosive coating inside for large tanks
Q What about pipelines?
A Galvanized steel pipes of class B or C are normally used. Copper pipes can also be used. Heat resistant plastic piping, if available, can also be used.
Q  Are there different types of collectors? If so, how to select the best one?
A

Yes, the best collectors are those with

  • high quality material for long life, say 10-15 years,(check out our page on Solar Water Heaters)

  • good workmanship to make collector water-proof and dust-proof,

  • high efficiency
Q   You said that the hot water will be available for 300 days in a year. How about the rest of the days?
A

SHWS can be provided with back up heating system by

- Electrical heater or - Boilers run on furnace oil/fire wood/coal or one bathroom should have elec. heater.
Q  How much money do we have to spend for maintenance?
A

Maintenance is minimal :

-Periodic glass cleaning, -Check for leakages and valve functioning
Q Are there any governmental incentives, subsidies, loans etc.?
A

Yes

  • Soft loan from IREDA & some banks repayable over 5 to 8 years at low interest.

  • 100% depreciation tax relief for profit making companies

  • Limited subsidy  on  innovative solar systems.
Q   How much does a solar hot water system cost?
A.

a) Domestic System (100 LPD at 60o C )

c) Rs. 17,000/- to Rs. 22,000/- as per quality

b) Non domestic System ( Range 60o to 90o C ): Rs. 130/- to 170/- per unit(100 lpd)
Q What about Payback?
A The chart explains all!