WHAT IS A SOLAR WATER HEATER ?

Solar water heaters to collect the solar energy from the sun to generate heat (not electricity) and provides hot water at a temperature of 60-90oC for application such as bathing, cloth washing, dish washing, industrial processes, swimming pool, etc. 

 Solar energy is the main energy source for our planet as it is responsible for providing energy for plant growth and providing the warmth that makes our planet habitable.

How does it work? 

The Sun’s rays radiates on the collector (a component of solar water heating system). A black absorbing surface (absorber) inside the collectors absorbs solar radiation and transfers the heat energy to water flowing through it. Heated water is collected in a tank which is insulated to prevent heat loss. Circulation of water from the tank through the collectors and back to the tank continues automatically due to thermosiphon system.
 What types of systems are available in the market? 
 There are two types of solar water heater are available in the market:
1. Flat Collector solar water heater (Pic.1): Solar radiation is absorbed by flat plate collectors which consist of an insulated outer metallic box covered on the top with glass sheet.
2. Evacuated Tube Collector (Pic.2): The Collector is made of double layer borosilicate glass tubes evacuated for providing insulation.

What are requirements for installation ? 

The basic requirement for SWH is the availability facing the sun.  it could be the roof of the house.
What about the multistory building, can SWH be installed there?
Yes. In multistoried buildings even if the space for installation can be made available on the roof, and the systems are installed there, the piping from the system to the use point will become long leading to extra cost as well as to extra heat losses. A better option in such cases could be installation of the systems on the wall mounted brackets, close to the bathrooms.

Will they work on cloudy days ? 

For totally cloudy days the output of SWH system would be ZERO. On partially cloudy days some output can be expected. But, the system can be designed with a suitable heating back up heater to take care of hot water demand on cloudy days.

Will I get hot water in the morning when sun is not there ? 

Hot water produced by the solar system during the day is stored in an insulated storage tank & water remains hot without significant drop in temperature for around 24 hrs. Thus water heated during the previous day should be available for use in the next morning.

What are the maintenance requirements ? 

Domestic solar water heating systems do not need significant maintenance requirements. Occasional leakages in the plumbing could be easily repaired by common plumbers. In case quality of water is hard, scale deposition in the collectors may result over the years. This may require descaling with acids for which it is best to contact the suppliers. Broken glass may also have to be replaced by the suppliers. If outside exposed surfaces are painted, the paint may have to be redone every 2-3 years to prevent corrosion of the surfaces.

 

 

Written : admin