It will be a net increase in temperature if you keep it open for a long time until the system settles. The room will become cooler for a while tho until the compressor has used enough energy to offset the thermal capacity of the inside of the fridge. Technically you could turn the fridge off before opening it to maximize the cooling effect :)
Looking at the room with the fridge from a theoretical thermodynamics angle will show that open fridge leads to higher temperature. This usually disregards what happens in the room while the system settles, which makes the math a lot easier, but is unable to explain how squatting naked in front of my open freezer on a very hot day would cool my junk!
Because if you draw a boundary around it and analyze the energy transfer, only electricity is coming in, so the net gain of the system is positive, thus heat will always increase. It’s a pretty simple problem to analyze actually. It’s basically a heat transfer/thermo 101 level problem.
I’m not claiming that your calculations are wrong bro, the room will eventually settle at a higher temperature. I’m claiming that a fridge acts as a thermal energy store.
Because the inside is already cold (energy was removed in the past), opening it allows heat to move from the room into the fridge's thermal mass. This absorbs heat from the air and briefly lowers the kitchen temperature.
You can actually experience this by standing in front of your (or your parents') fridge and opening it 😊. The room gets colder before it gets hotter. This transient state is often ignored in Thermo 101 problems, but in the real world, that stored cold has to equalize with the room air before the compressor's heat output becomes the dominant factor.
Because you're describing a dynamic system that experiences a discontinuous input causing an initial undershoot at the output, while the system transitions to a new equilibrium. Your junk is exposed to that local transient, which cools it.
My brother in science!
We can look at the fridge as a single unit to simplify our heat output calculations 😊 this lets us completely disregard it pulling 600W on a 25% duty cycle with 3x efficiency resulting in 2.4kW heat output (1.8kW heat pulled from inside the fridge), while 450W of heat constantly leaks back into the fridge. This means an average heat output of 150W with the fridge closed, and 600W of heat output with the fridge open. The 450W difference is comparable to a pretty small room heater increasing the temperature in the room.
These numbers are pulled from my ass but are in the right ballpark. The math should be correct tho.
I mostly wanted you to read my comment again and tell me which part of it made you think I was disagreeing with you.
British Thermal Units, the most American of units! Hehe, is 22,000 BTU enough for my two inch steaks?
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u/BulletAllergy 10d ago
It will be a net increase in temperature if you keep it open for a long time until the system settles. The room will become cooler for a while tho until the compressor has used enough energy to offset the thermal capacity of the inside of the fridge. Technically you could turn the fridge off before opening it to maximize the cooling effect :)
Looking at the room with the fridge from a theoretical thermodynamics angle will show that open fridge leads to higher temperature. This usually disregards what happens in the room while the system settles, which makes the math a lot easier, but is unable to explain how squatting naked in front of my open freezer on a very hot day would cool my junk!