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Freezer Efficiency and Environment Temperature
Name: Frank
Status: Other
Grade: Other
Location: CO
Country: United States
Date: June 2006
Question:
Several people have told me that a freezer works
much harder if it is in a very cold environment. That makes no
sense to me. I am wondering if that is correct.
Replies:
Frank,
I suppose the confusing part of that explanation is understanding
why a freezer should have to work harder when it is absorbing less
heat from its environment. Not to worry, if it is freezing outside
the freezer will not have to work at all.
On the other hand, the way most modern refrigerating units work is
based off of evaporation. Simply put, when any substance makes the
change from a liquid to a gaseous state, it must absorb a larger
amount of energy from its environment. Evaporate this liquid in
metal tubing with plenty of air flowing over them, and you will cool
the air. Use a compressor on that gas, and Boyle's law takes over,
raising the temperature of the gas tremendously. If the heat has
somewhere to 'go', such as into air flowing over another set of
coils, then the compressed (and now re-cooled) gas will condense
back into liquid, ready to be pumped back through the system.
This whole system works fairly well, provided the outside
temperature is in a range where the selected refrigerant can
effectively bleed off its excess heat. If it is too hot, it is
harder to shed that heat into the environment.
If it is too cold, the refrigerant may become to cold to effectively
take heat from the air it is supposed to be cooling.
Ryan Belscamper
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Update: June 2012
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