I now have a heat pump installed in my house and have been thinking over how I might make it more efficient. At the same time I had R-50 insulation installed in the attic and under the floor, on top of the R-15 which was already there. Presently there is a pellet stove which works quite well and wasn’t too expensive this last winter. But, this winter was a mild one. The problem with the pellet stove is that it leaves a temperature differential from floor to ceiling unless we run the ceiling fan. But I don’t like that fan because it is near my computer station and the wind is annoying. The heat pump system is claimed to have a more even temperature and the vents will be located near the windows and away from us humans.
On a perusal of how heat pumps work I was watching for how to make it more efficient. There was no mention of placing a sun reflector to maximize the winter heat-generating capacity of the external portion of the heat pump. That may not be a lot of heat, but it is some. Also, there is the possibility of surrounding the 3x3x3 foot external pump and fan assembly with 55-gallon barrels of water with a bit of antifreeze, which would ease the night-time temperature drop. The air then entering the heat pump would be warmer and wouldn’t require so much energy to heat the fluids that heat the house. Also in the summer the barrels could be shaded to sunshine and exposed to night air and thus have cooler air for operating the cooling cycle air conditioning.
Another possibility for improving the efficiency would be to incorporate a standard swamp cooler design into the system. The idea is to surround the intake vents into the heat exchanger with large water-cooled porous fabrics. Thus the air moving through the heat exchanger coils would be cooler in the summer which would increase the efficiency. It would give the combined efficiency of a swamp cooler and the heat pump, but the air within the house would not be subjected to the dampness of a swamp cooler.
If these systems were all used it might cut the electrical cost of thermoregulation of a house to half.