Solar Water Heaters

Solar water heaters also called solar hot water. It can be a cost-effective way to generate hot water
for your home. They can be used in any climate, and the fuel they use sunshine is free .Solar hot water
is water heated by the use of solar energy.

Working Principle: passive systems Thermosyphon solar water heater is open to air and relies on water’s natural circulation. When water in vacuum tube is heated, it rises naturally into storage tank, while cold water in storage tank flow back vacuum tube . A thermosiphon system relies on warm water rising, a phenomenon known as natural convection, to circulate water through the solar absorber and to the tank. In this type of installation, the tank must be located above the absorber tubes/panel. As water in the absorber heats, it becomes lighter and naturally rises into the tank above. Meanwhile, cooler water in the tank flows downwards into the absorber, thus causing circulation throughout the system. This system is widely used with both flat plate and evacuated tube absorbers.

 

 

 

Active Systems Active solar water heater systems use electric pumps, valves, and controllers to circulate water or other heat-transfer fluids through the collectors. They are usually more expensive than passive systems but generally more efficient. Active systems are often easier to retrofit than passive systems because their storage tanks do not need to be installed above or close to the collectors. If installed using a PV panel to operate the pump, an active system can operate even during a power outage. The cold water supply is connected to the solar storage tank. Water to be heated circulates between the storage tank and the solar collectors. The output from the solar storage tank becomes the cold water connection to the conventional gas, electric or oil water heater. When a hot tap is opened, pre-heated?water is drawn from storage into the conventional?water heater. The burner or electric element turns on only if the temperature cannot be maintained by the solar heater. Most properly-designed solar water heaters will supply 70 per cent or more of all the energy needed for water heating.

 

 

Structure composition
Compact Solar water heating systems include storage tanks and solar collectors.

Separated solar water heater include storage tanks and solar collectors, electric pumps, ,system
controllers relief valve etc.