If we are desuperheating our water, wouldn't it make sense to design a system that at least in cooling mode would just recirculate water to a 100 gallon water preheat tank? Seems to me that one, you could heat up some hot water fast, say 15 - 40 minutes WITHOUT using city or well water. (I see some economies here because you would start off NOT using additional water). Adding what I will call main water coil cooling would just be a matter of adding an additional valve or two. Having two heat exchange coils in one unit open up some interesting possibilities, but they would have to be properly designed in from the factory.