Solar water heaters use energy from the sun to heat water. Solar water heaters are designed to serve as preheaters for conventional storage or demand water heaters. It have heat collector to collect the solar heat efficiently, heat accumulator tank to keep the heat for long hours, and heat transporter such as the piping to transfer the heat with minimum loss, and heat exchanger.
While the initial cost of solar water heater is high but it can save a lot of money over the long term. Solar water heaters are much less common than they were during the 1970s and early 1980s but the units available today tend to be considerably less expensive and more reliable. At today’s prices, solar water heaters compete very well with electric and propane water heaters on a life-cycle cost basis, though they are still usually more expensive than natural gas.
How a Solar Water Heating System Works
A Solar Water Heating system uses the sun to heat either water or a heat-transfer fluid in an instrument called a “collector” which is generally mounted on a roof. The heated water is then stored in a tank similar to a conventional gas or electric water tank. Some systems use an electric pump to circulate the fluid through the collectors.
A Solar Water Heating system uses the sun to heat either water or a heat-transfer fluid in an instrument called a “collector” which is generally mounted on a roof. The heated water is then stored in a tank similar to a conventional gas or electric water tank. Some systems use an electric pump to circulate the fluid through the collectors.
Collector
The collector, which is generally mounted on the roof, absorbs the sun's light energy and changes it into heat energy.
The two most common type of collectors are flat-plate and evacuated-tube.
The collector, which is generally mounted on the roof, absorbs the sun's light energy and changes it into heat energy.
The two most common type of collectors are flat-plate and evacuated-tube.
Flat-Plate Collectors
Flat-plate collectors are the most common collector for residential water heating. A typical flat-plate collector is an insulated metal box with a glass or plastic cover—called the glazing—and a dark-coloured absorber plate.
Sunlight passes through the glazing and strikes the absorber plate, which heats up, thus changing solar radiation into heat energy. The heat is transferred to the liquid passing through the collector. The tubes are arranged in parallel and attached to the absorber plate so the heat absorbed by the absorber plate is readily conducted to the liquid.
Flat-plate collectors are the most common collector for residential water heating. A typical flat-plate collector is an insulated metal box with a glass or plastic cover—called the glazing—and a dark-coloured absorber plate.
Sunlight passes through the glazing and strikes the absorber plate, which heats up, thus changing solar radiation into heat energy. The heat is transferred to the liquid passing through the collector. The tubes are arranged in parallel and attached to the absorber plate so the heat absorbed by the absorber plate is readily conducted to the liquid.
Evacuated-Tube Collectors
Evacuated-tube collectors have the ability to heat water to higher temperatures than flat plate collectors. In an evacuated-tube collector, sunlight enters through the outer glass tube, strikes the absorber tube, and changes to heat.
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