Air solar collector, Solar hot air collector

Solar hot air collector

The solar air collector is a remote cousin of the more ubiquitous heating water solar collector. The principle of operation is similar. Sun radiation is absorbed in a layer of absorptive material, the energy in the light wavelength is converted to heat and trapped inside the collector casing (thanks to the greenhouse effect). The heat however is transferred to air and not to a liquid (water or anti-freeze liquid).The solar hot air collector is mounted outside the building usually flat on the southern wall of the building. The hot air is blown directly into the space to be heated or used as a pre heated air to the main air heater. So, this is one more way to achieve solar space heating

Advantages and Disadvantages of Hot Air Collectors

Solar Hot Air Collectors and other solar air heating methods have advantages and disadvantages (no single solution is perfect I’m afraid)

They are effective not only around noon time but also earlier and later in the day

Air doesn’t freeze like water (at least not where people live)

Small leaks in the ducts might cause a graceful performance degradation but not a major fault situation

Counting the plus points, let’s discuss the one minus point. Air collector is not as efficient as a liquid collector, simply because air is not as efficient heat transfer medium as liquid
 Installation Considerations

Air collectors are usually integrated into walls or into the roof (for a new building) or mounted on the wall as a retrofit. One air collector can provide heating to one standard size room and it is not a solution for the entire house. Usually a fan is used to circulate the hot air to the room

Solar hot air collectors are mounted on south-facing vertical walls or roofs. Solar radiation reaching the collector heats the absorber plate. Air passing through the collector picks up heat from the absorber plate.

Freezing, overheating and leaks are less troublesome for solar air collectors than for liquid collectors. But since liquid is a better heat conductor, solar collectors using water or a heat transfer fluid are more suited to hot water heating for the home. A solar hot air collector is most often used for space heating. There are two types of air collectors: glazed and unglazed.

Air Solar collector product