small compressor with oversized evap/cond

mejunkhound · 09-03-13, 09:12 AM

Replaced the 4T scroll compressor in my 4T Rheem air-air unit with a 2T compressor.

Mollier diagram says I should be able to boost COP from 3.5 or so to over 4 at 45 F, also put on lower speed evap and cond fans.

As soon as the weather turns cold, will see how well it works and post the results, noticeably lower noise levels seen immediately.

The 4T unit experienced severe frosting here in PNW with the 45F and 95% humidity days, hope to keep the evap temp above 32 F with having a 2x oversized evap.

PS: no need to worry about lack of BTUs at 20F and below, system switches over to GSHP at 40F (may adjust that also) and also have wood furnace backup.

09-03-13, 09:12 AM	#1
mejunkhound Apprentice EcoRenovator Join Date: Apr 2011 Location: PNW Posts: 197 Thanks: 0 Thanked 47 Times in 31 Posts	small compressor with oversized evap/cond Replaced the 4T scroll compressor in my 4T Rheem air-air unit with a 2T compressor. Mollier diagram says I should be able to boost COP from 3.5 or so to over 4 at 45 F, also put on lower speed evap and cond fans. As soon as the weather turns cold, will see how well it works and post the results, noticeably lower noise levels seen immediately. The 4T unit experienced severe frosting here in PNW with the 45F and 95% humidity days, hope to keep the evap temp above 32 F with having a 2x oversized evap. PS: no need to worry about lack of BTUs at 20F and below, system switches over to GSHP at 40F (may adjust that also) and also have wood furnace backup.