I did an inspection today of a mid-90s house with an indoor pool. The mechanical equipment looks to be a pretty good puzzle. Here are some photos: http://bailerhill.com/pool
Most of this equipment no longer works, and the owner is pondering how to replace it.
Heating and cooling of the pool room is by a heat pump / air handler with ductwork. When I looked at the outdoor unit, I noticed a second set of piping entering below the refrigerant lines. Both of these pipes are 1/2". The owner took the side cover off for a look at what's inside. To me, the connections look like a hack by the installer, not a factory-supplied configuration, although the stuff inside the box looks manufactured.
In the mechanical room, there are a couple of oddities. First, there's a bunch of copper piping with a couple of circulators. It was once piped into the pool pump/filter loop, but has been disconnected. That piping connects to a wall-mounted heat exchanger using the larger diameter connections. The smaller diameter connections are the same 1/2" piping that connects to the heat pump. There is a second heat exchanger in the supply airflow, shown in the last photo?
Not shown is a fairly recent propane pool heater and a bunch of new-ish PVC piping for it.
With me so far? This was a quick visit, and I didn't have time to do more than snap some photos.
It looks to me like the installer was trying to heat the pool water with the same heat pump that heats (or cools) the room. I'm gonna go out on a limb here and say that the installer went into mad-scientist mode, bought a bunch of stuff from the supply house, put it together, and tried to make it work. Is this even a remotely feasible idea? Any other interpretations as to what the intent of this set-up is?
For the record, I advised the owner that he needs to identify and hire a competent mechanical designer to evaluate the building and come up with a system that will provide heating, cooling, and humidity control.