Solar Water Heaters utilizes solar energy to heat water that is stored in insulated tanks for use. The water in the tube collectors gets heated by the solar energy and moves up in the insulated tank through the process of thermo-siphoning. There are two major types of Solar Water Heaters:
The conventional Flat Plate Collector (FPC) technology
New and more efficient Evacuated Tube Collector (ETC) technology
ETC consists of two tubes made from extremely strong borosilicate glass and can resist hail stoning up to one inch size. Advantages of ETC over FPC are:
More efficient as sunrays are always perpendicular to the surface of the glass tubes and therefore less reflective losses.
More cost effective as it does not require costly copper.
More suitable for hard water.
Very low maintenance.
Though the size of the system depends on many factors, as a rule of thumb; it is calculated at 25 liters per users per day (100 LPD for 4 users and so on).
Hot water output temperature
The system can deliver hot water from 45o to 75oC depending on the season & sunshine.
Guaranty & Product life
The system is designed to last 10 to 15 years and comes with a warranty of five years.
Both central govenrment and state government subsidies are available (subject to change as per Government Order).