When water or any liquid having a boiling point near to water is heated with direct exposure of SUN rays, this form of energy used in heating the liquid is called SOLAR Thermal.

Heating of daily use Water through the above process is done in a system called SOLAR Water Heater. This system consists of

  • a. Collectors – collects heat from the Sun and heats up the water
  • b. Hot Water Storage Tank – store the hot water which comes out of the collectors.


Based on Collectors, there are two types of SOLAR Water

  • 1. ETC - Evacuated Tube Collectors
  • 2. FPC - Flat Plate Collectors


What is difference between SOLAR ETC and SOLAR FPC Water Heater ?

In an ETC system of thermal heating, very strong borosil glass tubes are used to heat water. These Borosilite tubes are coated with heat conducting chemicals, and when water is passed through them for few hours, the heat conducting coating on the glass tubes heat the water passing with-in. Though glass is fragile but systems made on this are very economical and more and more are being used widely.

In FPC system water is heated either in copper / aluminum tubes which act as collectors or through heat exchanger which are fitted in hot water storage tank. This is an advance version of thermal heating and it is compatible with advance settings to gain high temperature using heat ex-changer. It is also compatible with pressure pumps. It works with copper or aluminum tubes covered with toughened glass plate. Its price is comparatively high.

SOLAR hot water collection arrays don’t need much attention either. Sometime we use a window wash brush, biodegradable soap, and water to clean the tubes.