Re:US companies are producing heat pumps that work below -20...
by mikeyouse on Wednesday December 28, 2022 @12:44PM
(#34163566)
Yep, here's a spec sheet for a unit I'm looking at as a drop-in ducted replacement for my existing system -- it has all of the models listed, but I'm looking at the 4-ton unit (12k btu per ton, so 4-ton = 48k BTU, hence the MDU18048): https://mrcool.com/wp-content/dox_repo/mc-uni-perf-ss-en-01....
It takes 7kw at 17ºF to provide 48k BTU. There are 0.293W/hr per BTU so 7,000W = 25k BTU "in" and 48k BTU "out" or a COP of 1.9. At -15ºF, it's using 5.9KW but can only produce 28,500. So a COP of ~1.4. Still better than electric resistive heating but not by much. At 40ºF, the COP is more like 3.3 which is in line with the very efficient numbers.
Fortunately my 99% design temp is ~8ºF and my area only sees 20hrs below zero per year, so this will work just fine for me.
It takes 7kw at 17ºF to provide 48k BTU. There are 0.293W/hr per BTU so 7,000W = 25k BTU "in" and 48k BTU "out" or a COP of 1.9. At -15ºF, it's using 5.9KW but can only produce 28,500. So a COP of ~1.4. Still better than electric resistive heating but not by much. At 40ºF, the COP is more like 3.3 which is in line with the very efficient numbers.
Fortunately my 99% design temp is ~8ºF and my area only sees 20hrs below zero per year, so this will work just fine for me.