I know it is a strange concept for many people to wrap their heads around (because I’ve had to explain it entirely too many times in recent history) – but opening your refrigerator/freezer, or setting up a portable air conditioning unit in the center of a room *with no heat exhaust to send the heat outside of the room* will only ever make the room hotter!
It will keep going until it either hits an equilibrium point where the heat being lost from the room is the same as the heat being produced (which can be surprisingly high through good insulated walls and a reasonably sealed doorway) – or until the hardware fails due to overheating.
Some high level, fairly simplified, Scientific Theory for those unfamiliar with it (you don’t need to fully understand it, but some basic foundation helps if you follow along):
- Thermodynamics is the study of the relationship between different forms of energy – specifically focusing for the most part on *heat* and its interactions with everything else.
- Scientific “Laws” are fundamental concepts accepted by scientists worldwide as being as close to 100% proven, indisputable facts as possible. When exploring new concepts or making a new hypothesis or theory – these Laws can simply be assumed as true, you don’t have to prove them, because they’ve been proven. (On the rare occasion one of these “Laws” does get disproved – our scientific understanding of fundamental reality itself has to shift)
- The 2nd Law of Thermodynamics tells us (paraphrasing, but feel free to dig into the papers on the subject if interested) that whenever anything happens – the total heat of the universe goes up. The more perfect your energy efficiency the less it goes up – but it ALWAYS goes up.
- This means that you can move heat from 1 place to somewhere else, or spread it out – but you can’t do literally anything without heat being produced
As it turns out – we’ve made progress and air conditioners/refrigerators/freezers are more efficient than they used to be – but they still aren’t very efficient, and they produce A LOT of heat when they are working hard.
This seems counter-intuitive – things we use for cooling produce a ton of heat – but they basically work like this:
- They have a fully closed system of pipes that coolant gets pumped through, in a never ending loop.
- Instead of *just* a pump – the HOT end of the system actually uses a compressor, which literally *squeezes* as much heat as it can out of the coolant, making it nice and cold as it goes back into the loop.
- There are fans/blower motors at BOTH ends of the loop.
- At the COLD end – the blowers blow air across a heat radiator block (with the coolant lines running through it) to pull heat out of it before it gets sent out into your house, or your freezer/refrigerator.
- At the HOT end – the blowers also blow air across a radiator block (with the coolant lines running through it) – but at this end it is to pull the heat out of the system and exhaust it either into your house for your A/C to deal with (in the case of the freezer/refrigerator), or outside of your house in the case of your A/C system.
- The blower at the exhaust side tends to be a lot stronger, with a larger radiator block – because of all that heat!
Before we bring this all the way back to my original point, you may have noticed I already said your freezer/refrigerator already exhausts its heat into your house, warming it up. If you find the exhaust from your refrigerator you can feel this for yourself (usually on the bottom) – but it isn’t a problem because a well made freezer/refrigerator is well insulated and doesn’t actually need to run constantly to stay at the correct temperature if it stays closed. It does have an impact on your home temperature, but not a big one.
Now back to the original point.
Putting the A/C unit in the middle of the room, or leaving the door of the freezer/refrigerator open, causes 1 more big issue that really causes the heat to spike out of control. Namely, it mixes the exhaust heat directly back into the air intake – making the system work harder and harder while constantly losing ground to the growing overall heat trapped in the room.
Now, there is still a limit to the spiral. You (probably) won’t light your house on fire, or even reach temperatures that are actually dangerous to humans in the room. With the heat, the pressure in the room will also build – and it will force its way out of any crack it can find. If someone opens a door to the room, a big rush of hot air will go out – and cooler air will come in. By design, buildings are pretty breathable (people do need to breathe) – so there are lots of places for heat to work its way out. Also the coolant systems themselves have limits, and safety regulators built into the good ones – so they’ll cap themselves out and/or burn themselves out.
You’ll get your room uncomfortably hot though. And if you pay your own electric bill and use A/C – you’ll know how much more expensive it is to heat a room this way instead of just using an energy efficient space heater designed for the purpose.
SO DON’T DO IT!!!
Just leave the Freezer/Refrigerator shut. And if you put an Air Conditioner in an internal room, run some exhaust conduit to take the hot air outside. It is cheaper than even just the first week’s electric bill spike.
+ Side Note +
If you install the A/C to cool one room and exhaust heat into another part of the building – you do avoid the big heat feedback loop – but you are just building a really inefficient walk-in cooler or freezer. There are a few valid reasons to do it, but make sure that is what you want to do.