View single post by Keinokuorma
 Posted: Mon Mar 3rd, 2008 03:13 pm
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Keinokuorma



Joined: Mon Jun 26th, 2006
Location: Finland
Posts: 1248
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Of course these add up to the total result. But in general, if a heat pump was of weaker efficiency ratio than 1,0 it would be easier and more economical to just heat with direct elecricity.

2,4 for an efficiency factor on a fridge that is already cold inside, hot outside, and possibly a wee bit dusty and frosty, would be plausible. BTW its heating factor would be 3,4 then... all of the work done in the compressor will eventually turn into heat on the outside... so those 120-some watts PLUS the heat pumped from the inside, are exhausted on the outside.

Although it would not heat the kitchen by more than those 120-some watts when it was running... every time you open the door some of the exhausted heat enters and must be pumped out again... plus defrost heat etc... but what I'm going after here is that the fridge is more efficient in moving heat out of the cabinet, than in producing heat of its own or consuming energy.

There are of course limits for the function.

If the cabinet interior is so cold that the freon no more evaporates, no more heat will be extracted. The system will run continuously and produce heat respectively to its energy consumption.

If the environment where the fridge was installed, gets too hot for much heat to dissipate, the freon that is fed back to the evaporator is still hot. Although it evaporates it is already about as warm as the interior air, and the cooling isn't very efficient either.

But as said before, I'm rather sure that the 900 BTU rating means that it can nominally move 900 BTU/h heat outside of the cabinet. Also if everything is right, it will cycle off for good long periods when the temperature has been reached, and it will not consume energy comparably to 900 BTU/h even if running constantly.



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