Solar Water Heating System

We have a wide range of water heaters with capacities varying from 150LPD to 10,000    LPD. The applications include domestic water heating, commercial establishments like hotels, hospitals, resorts, hostels etc.
Solar water heater produces hot water using energy from sunlight. Hot water is used for different applications, domestic as well as industrial. By using solar water heaters, we can save the electricity and in turn save a lot of money.


Solar Water heater consists of mainly 2 parts. One is the collector and other is Insulated tank. The cold water in the collector get heated up and collected in the tank by thermo siphon principle. This circulation continue till the water in the tank heated up to 60-80° centigrade. The hot water in the tank remains hot for more than 24 hours.

Domestic Models : 150 LPD , 200LPD, 250 LPD & 300 LPD (Litres per Day)
Industrial Models :   above 500 LPD upto 10,000LPD


Evacuated tubes are the absorber of the solar water heater. They absorb solar energy converting it into heat for use in water heating. Evacuated tubes have already been used for years in Germany, Canada, China and the UK. There are several types of evacuated tubes in use in the solar industry. Solar collectors use the most common “twin-glass tube”. This type of tube is chosen for its reliability, performance and low manufacturing cost.

Each evacuated tube consists of two glass tubes made from extremely strong borosilicate glass. The outer tube is transparent allowing light rays to pass through with minimal reflection. The inner tube is coated with a special selective coating (Al-N/Al) which features excellent solar radiation absorption and minimal reflection properties. The top of the two tubes are fused together and the air contained in the space between the two layers of glass is pumped out while exposing the tube to high temperatures. This “evacuation” of the gasses forms a vacuum, which is an important factor in the performance of the evacuated tubes

Why a vacuum? As you would know if you have used a glass lined thermos flask, a vacuum is an excellent insulator. This is important because once the evacuated tube absorbs the radiation from the sun and converts it to heat, we don’t won’t to loose it!! The vacuum helps to achieve this. The insulation properties are so good that while the inside of the tube may be 150oC / 304oF , the outer tube is cold to touch. This means that evacuated tube water heaters can perform well even in cold weather when flat plate collectors perform poorly due to heat loss (during high Delta-T conditions).

In order to maintain the vacuum between the two glass layers, a barium getter is used (the same as in television tubes). During manufacture of the evacuated tube this getter is exposed to high temperatures which cause the bottom of the evacuated tube to be coated with a pure layer of barium. This barium layer actively absorbs any CO, CO2, N2, O2, H2O and H2 out-gassed from the evacuated tube during storage and operation, thus helping to maintaining the vacuum. The barium layer also provides a clear visual indicator of the vacuum status. The silver colored barium layer will turn white if the vacuum is ever lost. This makes it easy to determine whether or not a tube is in good condition. Evacuated tubes are aligned in parallel; the angle of mounting depends upon the latitude of your location. In a North South orientation the tubes can passively track heat from the sun all day. In an East West orientation they can track the sun all year round.

The efficiency of a evacuated water heater is dependent upon a number of factors, one important one being the level of evacuated radiation (isolation) in your region. To learn more about isolation and the average values for your area.

Configurations & features of Vacuum tube

Configuration of vacuum tube

Full glass vacuum tube is composed by the inner glass that is with the selective-absorbing layer of the solar and the covering glass tube, and one terminal of the inner glass tube, which is supported by the brace shelf with the air-absorbing in the covering glass vacuum sealing terminal, is the dome shape; while the ring type open terminal is formed by the melting & and sealing between another terminal and the covering glass tube.