Solar Insights: Is solar hot water (and cooling) the next big thing? by Giles Parkinson

Amid the dramatic cost reductions and soaring demand for solar PV (photovoltaic) technologies in Australia and across the world, the long established idea of using the sun to heat water has taken a back seat.  In Australia, where SHW once dominated the local rooftop industry, installations were outpointed by rooftop PV by a factor of 5 in the last year.

But now SHW it is tipped to make a return to centre stage, along with relatively new solar thermal technologies that use the sun to provide heating and cooling for office and building spaces, district heating and under-floor heating in cooler climates, as well as for industrial processes and in hybrid systems with solar PV (known at PV-T). At a larger scale, it could one day be used for water treatment and desalination.

According to the International Energy Agency, solar heating and cooling (SHC) could make a dramatic impact on the world’s electricity grids, providing 17 per cent of all energy required for heating in buildings, industrial processes, swimming pools, and 17 per cent of cooling needs. This amounts to 3,500GW of capacity for heating, 1,000GW of capacity for cooling, and a further 200GW of capacity for swimming pools (up from 20GW now).