I am learning all about heat radiation in Physics. There is a question I am doing about Solar panels. It asks, why do glass covers improve the efficient of solar panels? I dont really understand. How do they?? thanks :D x
the glass has an anti-reflective coating that helps the panel absorb more light (to convert to electricity) thant it would if the glass were not there. the other purpose of glass is to retain heat and strengthen the panel
For a solar thermal panel, the idea is to get the inside as hot as possible. There are three ways to lose heat - conduction, convection, and radiation. By cutting off airflow, the glass cover reduces cooling by convection.
Clear glass will allow most of the electromagnetic energy of sunlight into the air-tight volume of the solar panel. The light strikes the black coated metal tubes and the black coated backing, and is absorbed as heat. Part of this heat will radiate as infrared radiation, and much of this will leave through the glass. But a great deal of it will initially remain in the metal as heat. This heat will be partially transferred to the surrounding air, but because the glass stops the mixing of this air with the rest of the atmosphere, this heat will stay mostly contained within the solar panel. If the glass were not there, there would be a huge loss of heat into the surrounding air.
