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There are several different types of solar collector, which transfer the sun's heat to water. This animation illustrates a system based on evacuated tubes.
The solar hot water panel (solar collector) is typically mounted on a south facing roof. The panel includes a row of evacuated (vacuum) tubes that trap heat from the sun.
Inside the tubes are narrow heat pipes containing a liquid - typically a mixture of water and glycol (i.e. antifreeze). As solar energy is absorbed by the evacuated tube, the liquid in the narrow pipes becomes a hot vapour that rises to the top, where there is a wider copper 'bulb' (the condensor). This provides a larger surface area for heat transfer.
Heat is passed from the condensor to a copper header (also sometimes called the collector or heat exchanger). The 'antifreeze' condenses and returns to the bottom of the narrow pipe where it is reheated by the sun, creating a cycle of heating and cooling that efficiently transfers heat from the evacuated tube to the copper header.
A pump is used to circulate antifreeze through pipes connected to the
copper header within the solar panel. The hot liquid from the solar collector
flows through a copper coil within a conventional water storage tank,
where the heat is absorbed. |
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