At the mention of ‘solar’, most of us think about arrays of blue, sun-facing panels that generate electricity. That is because ‘solar photovoltaic’, for historical reasons, grew very fast, in India and elsewhere, and became ubiquitous. But there is another ‘solar’, simpler and traditional, which is known to give a better bang for every buck invested. To wit, ‘solar thermal’.
‘Solar PV’ works by photons in sun’s rays knocking off electrons in the semi-conducting material in the panels and channels them through a wire—the stream of electrons is electricity. Solar PV, therefore, works best where there is lot of sunlight. Solar thermal systems, in contrast, suck up sun’s heat and conduct it to where it is needed – such as for drying of spices or fish or wet paint.
