Quote:
Originally Posted by Daox
Excellent point Piwoslaw. Taking it a bit further though, wouldn't my ~92% efficient furnace be more efficient than my fridge which is at most running off ~40% efficient grid power (which is supposedly renewable energy)?
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Your fridge is a heat pump with CoP ~2-3. If you heated your house with a heat pump with similar CoP, then you wouldn't be losing too much efficiency, but with a furnace (with CoP < 1) you need to use more energy to make up for the heat that you literally threw out the window. As I mentioned earlier, it will be almost impossible to measure an increase in fuel for heating, since that depends on so many parameters and the amount of heat being tranferred outside in the jugs will be small compared to how much is needed to heat the whole house. Now, a controlled experiment, with only a refrigerator in a closed off room... blahblahblah. Factoring in grid efficiency also changes the equation slightly.
If your refrigerator's coils went through the wall and always pumped heat to the great outdoors, then doing this experiment wouldn't effect your house's heating.
In any case, I haven't taken into account waste heat from the refrigerator's compressor helping to heat the house, nor heat lost while opening windows/doors to swap jugs.