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01-27-12, 03:22 PM | #1 |
Master EcoRenovator
Join Date: Dec 2008
Location: Vancouver Island BC
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I'm not sure how well the actual unit handles cold but at -4C my controller switches to the electric backup. I doubt the controller has any knowledge at all of the heat pumps ability to work at this temp and is just programmed to switch over.
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01-27-12, 03:51 PM | #2 | |
Lex Parsimoniae
Join Date: Feb 2009
Location: Woburn, MA
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Quote:
The Sanyos do a good job down in that range. They really start using more power when it gets down in the teens, but can still keep the house nice and warm, until we get single digits.. At about 8 deg F (-13.33C) power use maxes out, but is still not too bad. When it hits 5 deg F (-15C), that's when I just turn them off and go to backup. We've been lucky this season, since it's only dropped to 4 °F, once or twice..
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02-11-12, 06:46 AM | #3 |
Lurking Renovator
Join Date: Jan 2012
Location: Artic Circle
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I feel the residential heating by ASHP is not specially challenging in N-America,if the widgets ,supplied locally, could only somehow manage -15degC with reasonable COP (>>1,5).
In N-Europe practically all AC (R410) at heating mode cope easily with that minus15C ... some even "well" with -25C. Below one collection of test reports (note, defrosting included in the results) in Finnish: Ilmalämpöpumppuvertailu - VTT:n testiraportit | Scanoffice and further one sample of ME`s MUZ/MSZ FD35VABH -model: http://www.scanoffice.fi/uploads/vtt...S-08820-10.pdf Look at pdf.page 9/11 (POWER W vs. TEMPERATURE C(elsius) The corresponding COP vs.temp. (defrosting incl.!) shown at .pdf 7/11 It is for sure the pumps do not enjoy the conditions -20C ... -30C. The deep-cold POE-oils should be returned back to the compressor at random basis (forced defrosting mode,trigged like egg-clock by software) ,eventhough there is no frost at the evaporator due to extra low humidity in the outside air (RH <30%)! |
The Following User Says Thank You to dc€x For This Useful Post: | abogart (02-11-12) |
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