With a full and an empty freezer, of course under identical conditions, heat can only be transferred into the fridge in function of the surface area exposed to the heat * the composite K-factor of the material and the insulation * the temperature difference between the outside – and the inner wall. For example, every manual teaches about heating techniques, and by extension also cooling techniques. Why then does everyone keep claiming that a full fridge would consume more? I’m not talking about a layer of ice on the inside that obviously changes the k-factor, nor about opening much or less, searching longer, etc… Just 2 identical freezers that have been on for quite some time, to eliminate all transitional phenomena. Close.
Answer
You’re right if both freezers are up to temperature and won’t open. But when you open them, a lot more heat can be absorbed in the full freezer than in the empty one. The heat capacity per kilogram of air is two times smaller than that of (say) ice, but the density is a thousand times smaller. Even though the air warms to room temperature, it contains very little heat.
Answered by
Professor Walter Lauriks
Physics Acoustics
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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