rebuilding GTHP with low COP

stevehull · 02-13-16, 08:44 PM

I have a 12 KBTU water source heat pump (R22) that keeps the office in my shop warm in winter and cool in summer. The problem is that the COP is rather low - about 2. Draws about 6 amps and I bet I can decrease that to 3 amps with a more efficient scroll.

The reason is likely the old reciprocating compressor and I am betting that a newer scroll would work in its place - and far more efficiently.

Is it too much to think I can literally cut out the old inefficient compressor, rebraze in a new one, evacuate/refill - and have it done? And it is a 120 V compressor . . .

The unit is a late 80's demo model made for WaterFurnace. I picked it up about 20 years ago for $50, hooked up some garden hoses for inlet/outlet water lines and away it went. Confirmed the COP by measuring the difference of in/out water temps and the water volume through the system. The plate also says 12,000 . . . . but it was fun to verify.

In all that time, I have never had to recharge it and the only fix was a deteriorating start capacitor that was simple/cheap to replace.

The newer scroll compressors look quite nice - but will they work as a braze in replacement?

Steve

02-13-16, 08:44 PM	#1
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	rebuilding GTHP with low COP I have a 12 KBTU water source heat pump (R22) that keeps the office in my shop warm in winter and cool in summer. The problem is that the COP is rather low - about 2. Draws about 6 amps and I bet I can decrease that to 3 amps with a more efficient scroll. The reason is likely the old reciprocating compressor and I am betting that a newer scroll would work in its place - and far more efficiently. Is it too much to think I can literally cut out the old inefficient compressor, rebraze in a new one, evacuate/refill - and have it done? And it is a 120 V compressor . . . The unit is a late 80's demo model made for WaterFurnace. I picked it up about 20 years ago for $50, hooked up some garden hoses for inlet/outlet water lines and away it went. Confirmed the COP by measuring the difference of in/out water temps and the water volume through the system. The plate also says 12,000 . . . . but it was fun to verify. In all that time, I have never had to recharge it and the only fix was a deteriorating start capacitor that was simple/cheap to replace. The newer scroll compressors look quite nice - but will they work as a braze in replacement? Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990