Quote:
Originally Posted by jeff5may
IT CAN BE DONE. I am considering doing the same thing with a prefab window unit. Run the two heat exchangers in SERIES (not parallel) by swapping the cap tube out for a straight pipe. Pipe the condenser end into the reversing valve, and install a txv and check valve on the evaporator end. This way, the condenser will not burp liquid or fog into the compressor.
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You are correct in assuming that running both heat exchangers together will be more efficient. The more surface area and airflow you have, the more heat you can harvest from outdoors. How much more efficient? No one knows yet.
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I like it and this brings something to my mind:
I have a dehumidifier I made from a $10 second-hand window-unit that I gutted. I simply installed a drip hose into the drip-pan and placed it on a 5 gallon bucket. I used packing tape to seal up all of the side vents on the sheet metal shroud. and threw out the foam blocks that separate the hot side from the cold side.
Next I removed the cold-side fan blade.
Now, the unit is like a little piece of duct, bringing in air through the cold side and out the hot side, powered by the axial blades of the condenser fan.
The reason I bring this up, is that if you did a similar configuration (sandwich the compressor between the the series heat exchangers) and use the plumbing scheme you've described [Jeff], you would recover a majority of the heat from the compressor during heating mode. This configuration might also keep the unit from icing up on the colder days for two reasons:
1) You have a larger evaporator surface for the given heat load with the dual HX.
2) You have the compressor in there giving you the electric resistance heat from the electric motors (compressor & fan).