A Solar Water Heater is a device which provides hot water for any purpose using Sun’s thermal energy for heating the water. It is generally installed at the terrace or at any place where sunlight is available. The water gets heated during day time and is stored in an insulated storage tank for use when required including mornings. Solar water heaters for a domestic purpose are very popular as they suffice the need of hot water for bathing, washing, cleaning etc., particularly on cold days.
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A Solar Water Heater comprises of an array of solar collectors to collect solar energy and an insulated tank to store hot water. Both are connected to each other. During the day time, water in solar collectors gets heated which is either pumped or flow automatically on thermosyphon principle to the storage tank. Hot water is then stored in the tank which can be used for various applications.
Will it generate hot water on all days and in all seasons of the year?
It generates hot water on
- Clear sunny day – Maximum
- Partially cloudy day – Moderate
For how many days it will generate hot water in a year.
It will depend on local climate and number of sunny days. However, in India, provide the auxiliary backup heating system with Electrical heater at extra cost to take care of cloudy days, when Sun is not available. This may be around 300 to 325 days in India.
Where can it be installed?
It can be installed on.
- Building terrace
- Open Ground
But there should be:
- No shadowing
- South orientation for the collectors
- Collector Tilt = Latitude + 1500 thereof
- Overhead tank above SWHS system
Maximum possible temperature it could attain:
One can get water of about 60 to 80o C. The rise in temperature depends on:-
- Solar Radiation
- Weather Conditions
- Number of Solar collectors
Hours required heating the water:
- Normally, 6 to 7 hours of normal solar radiation is required to heat the water up to 60°C.
Quality of water needed:
Only soft and potable water is recommended for solar heater. The water from borewells is generally hard water and it is not recommended as it will cause scaling resulting into ultimate choking of the system. However, if there is hard water, it can be used with a special jacket type heat exchanger or with softener.
Normal Galvanized steel pipes of class “B” for cold water line & Precast PUF insulated, HDPE Pipe or “B” class Galvanized pipes for Hot Water Lines
Govt. of India, Ministry of Non-Renewable Energy has laid down certain minimum technical requirements for installation of solar water heating systems in the field. These have been made mandatory for manufacturers and suppliers and they are available on MNRE website: www.mnre.qov.in
These requirements have been prepared in such a way that even a layman can also check them and ensure that those are being adhered to by the manufacturers/suppliers. In case any manufacturer/supplier is found not sticking to these requirements, he may be blacklisted if informed to the government.