Put heat pump condenser in basement?
I have an old house with a substantial masonry (stone walls, concrete floor) unfinished basement --about 2000 square feet. Temperature down there is fairly constant 50-60's throughout the year. I'm in a moderately temperate mid-Atlantic climate where below freezing winters are normal (but rarely go below 10 degrees) and highs in summer rarely go above mid-90's.
Would it not be more efficient to locate the condenser unit of an air-to-air heat pump indoors in this basement? I am using the logic that the constant-temperature basement is more or less the equivalent of using a closed loop underground geothermal system, which gets its efficiency from having a consistent source of 50 degree heat.
In the winter the discharge from the heat pump would cool the basement and in the summer it would warm it.
There are a few posts about this online but none I have found are from someone who has actually done this. Does anyone actually have any experience?
Alternatively, there is an open (probably hand dug) well in the basement. Would this work as a source for a "groundwater" open loop geo system (assuming I can somehow figure out what the gallons per minute flow rate could be)?
Any thoughts on which would be the preferable option?
I am trying to avoid the cost of laying geothermal closed loop piping underground -- it's a fairly small lot and would require drilling holes.
One last thought, if you have to drill to lay closed loop pipe, wouldn't it be easier just to drill a well and use an open loop water system? It seems you could get away with one drilled well versus possibly multiple drilled holes for lots of closed loop pipe.