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eric4smith

It should lock you out for a configurable time after "n" opens.

It can lock the door in the night after dinner to prevent midnight snacking by the kids (or parents).

And should tweet to your account to shame you publicly after "n" number of opens.

What's the IP address of your fridge (just curious)?

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It will do all those things with its connection to the governments "Fit & Healthy" social credit application that was auto-updated the other day. Wanna complain after it locks you out? The only way to do so is by grabbing a rent-a-bike and cycle 20 miles to the nearest human interest centre. /s?

That's some evil totalitarian dystopia, we don't do things this way over here in the West.

Our fridge gives you freedom to open and close it how many times you want. More than that, by means of synergy with our health industry partners, it lets your good eating habits give you the best deal on your health insurance plan!

our freezer does that, every time after you open it, it somehow reduces the pressure (maybe it tries to suck out the warm air) making the door hard to open.

I'm pretty sure that's just done with electromagnets.

that's really just physics. warm air gets in through the opened door, after closing it rapidly cools down, because air does not hold that much heat energy. Because it cools it contracts, which reduces the pressure inside the freezer, causing the outside air pressure to hold the door shut more firmly.

No electromagnets or anything.

And it's a demonstration of just how much cold air is falling out when the door is opened. While less convenient, a chest freezer will do much better at holding the cold air even when opened.

While visiting rural northern Namibia, a Damara tribesman I was talking to asked me where I was from. Upon hearing that I was from a cold Northern part of the world, he commented that it must be great that half the year I didn't need to run my freezer.

I just stared at him, not knowing what to say. He stared back at me for a while and then started laughing. Then I realized he was screwing with me, and I just said, "Touche'".

if that were the case then i should be able open the door right after i closed it. realistically, even a pump could not be that fast. electromagnets sound like a much better explanation. simple logic too. whenever the temperature is higher than expected, turn the magnets on.

i think you are right, that makes a lot of sense, and is much simpler too. i was thinking that it would make sense to want to remove the warm air, with lower pressure being a sideeffect of that.

I think it is simply that cooling a gas will reduce its pressure if you maintain constant volume (Ideal gas law). So when you open the door you warmup the air inside, and when it cools down once to door is locked, the pressure is lower, locking the door. Then small leaks will equalize the pressure.

My side by side actually runs some pump that is not the compressor when you close the door. It runs for about 5 seconds, after which the doors are quite difficult to open. Air does not change temperature that fast without being forced to, so the idea that within 10 seconds it's harder to open because of a natural vacuum seems suspect.

Maybe 5 minutes after?

I tried doing some math on this, since you got me thinking!

Let's assume the "lock force" is 100N, and the surface of the fridge's door is 1 square meter. This means the pressure differential between inside and outside would be 100 Pa. One atmosphere is roughly 10^5 Pa, so you would need a pressure differential of 10^5 / 100 = 0.1% between inside and outside. Since PV=NRT, we deduce that DeltaP/P = DeltaT/T. Or, in other words, 0.1% pressure means 0.1% temperature. We live at around 300K, so that's 0.3K difference. A fridge is what, 0.5 m^3 ? And air is about 1.3 kg/m^3, specific heat of air is about 1kJ/kg, so we would be looking at removing 1.3 kg/m^3 * 0.5m^3 * 1 kJ/kg = 650 J in 10 seconds, or 65W. A fridge can apparently consume about 200W peak (from a quick Google search), so it seems feasible with an OK-tier efficiency.

In addition, if you add a pump, you could also just add a mechanical lock, couldn't you ?

Thanks for doing that math, truly.

I always assumed it pulled air out from the top of the freezer compartment, just to remove some of the hottest air. Inefficiencies in the seal will let air leak back in eventually, but probably slow enough that it doesn't affect the internal temperature that much.

Now I want to know the reasoning behind having a pump at all.

>A fridge can apparently consume about 200W peak

yes this seems right, i am able to run my fridge off an inverter connected to my vehicle battery if the power is out, even with a 150' run of extension cord - no issues at all, and 200W or thereabouts sounds like the numbers i saw.

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