How many USES? Let me count the ways.
Solar thermal is a competent inter-seasonal solution for many thermal applications that seek to reduce OpEx, GHG, and Carbon emissions.
One of the most common uses for solar heat is to simply heat hot water. This is often done in warmer climes but less so in colder areas.
In the DSH system hot water plays an integral part. The main DSH system is pressurized to 1-2BAR (14-28PSI). This is less than mains pressure but enough to prevent cavitation and air pockets.
The hot water tank has a coil near the bottom where solar heat is pumped. It is isolated from the water supply allowing the DSH system to run at its own pressures, and the plumbing to run at mains pressures..