COMMERCIAL and industrial solar energy systems are generally
classified according to the heat transfer medium used in
the collector loop (i.e., air or liquid). Although both systems share
basic fundamentals of conversion of solar radiant energy, the equipment
used in each is entirely different. Air systems are primarily
limited to forced-air space heating and industrial and agricultural
drying processes. Liquid systems are suitable for a broader range of
applications, such as hydronic space heating, service water heating,
industrial process water heating, energizing absorption air conditioning,
and pool heating, and as a heat source for series-coupled
heat pumps. Because of this wide range in capability, liquid systems
are more common than air systems in commercial industrial
applications.