By Richard Keech
Do solar air heaters or coolers live up to their promise?
At face value the idea of having a device which uses sunlight directly to heat air in winter seems like a good one. It’s the idea behind a number of products on the market that promise really high-efficiency heating for low cost. We can lump these together in the category ‘solar air heating’. Solar air heaters sometimes claim thermal efficiencies greatly in excess of that possible with a solar PV panel.