The water source for all of the heat pumps in the
building circulates in a closed piping loop, connected to
a cooling tower for summer cooling and a boiler for
winter heating. Control valves allow the water to bypass
either or both of these elements when they are not
needed (Figure 10.10). The primary energy benefit of
closed-loop heat pumps is that heat removed from overheated
interior spaces is used to provide heat for
underheated perimeter spaces during cold weather.