Russ, or any of the rest of you mechanical engineers out there, ever use something called an "Energy recovery heat pipe?" I don't mean the old pumped heat exchanger type. The ones I am talking about are manufactured by Heat Pipe Technology, Inc. They use passive exchange of R22 from a coil on the inlet side of a cooling coil piped to another coil on the outlet side. They only work during cooling season. The incoming hot outside or mixed air is precooled by giving up its heat to the R22 in the first coil, the gas moves to the second coil where it gives up its heat to the cold air stream, reheating it, and cooling the R22 enough to drop it back to the first coil again. These seem so much more energy efficient than either electric reheat coils or running a boiler all summer to dehumidify. Has anyone out there used one of these in the field?