required heated water, the auxiliary system boosts the water temperature the rest of
the way up to the desired temperature (Figure 2-5).
Solar Storage Tank in
Series With DHW
In either case, no other controls or valves are needed. The solar DHW preheating
system in series with an auxiliary heater is the most common solar heating
application. The cold water supply is almost always lower in temperature than the
solar storage tank, so solar energy can almost always be utilized.
Process Water Heating
Process water heating with solar systems is almost identical to domestic water
heating. One difference is the larger size of the system. If the process requires high
temperature water, evacuated tube collectors, which operate more efficiently at high
temperatures, may be used.
Some systems use no storage, but add the solar heat to the water as it is brought in.
This approach is most common when the solar system is fairly small compared to
the size of the load.
2.1 BASIC SYSTEM CONFIGURATION