Maintaining a Temporarily Unplugged Fridge
June 5, 2020 1:17 AM   Subscribe

Around this time every year my fridge starts making a loud buzzing sound that I think has to do with its fan or something plus the rising ambient temperature. Sometimes it stops on its own, but right now it is loud enough that I need to keep it unplugged so as not to disturb my neighbors tonight. What can I do to prevent my food from going bad if I need to keep the fridge unplugged for 5 hours or so?
posted by Kitchen Witch to Food & Drink (12 answers total) 1 user marked this as a favorite
 
The obvious answer is "don't open it". If you have a freezer you could also freeze big bottles of water and put the frozen bottles in the fridge right before you turn it off.
posted by EndsOfInvention at 1:35 AM on June 5, 2020 [4 favorites]


Yes, definitely don't open it. And make sure it is as full as possible of already cold things. You could also temporarily set the temp lower than normal in the hours preceding switching it off, but be careful of freezing perishables.
posted by mewsic at 2:06 AM on June 5, 2020 [1 favorite]


If you rent your apartment and the refrigerator is buzzing to the point that your neighbors are complaining and you are turning it off overnight, this is your landlord’s problem, not yours.
posted by rockindata at 2:33 AM on June 5, 2020 [9 favorites]


Not opening it. Check. Keeping it cold. Check.

I do live in an apartment, and the fridge came with it, so yes, technically this is my landlady's responsibility. However, I may have symptoms of COVID. It would be unethical for me to ask any of the members of our maintenance crew to come into my apartment right now.

In the morning I'll send some apology post-its to the doors of my neighbors letting them know where the sound is coming from. No one has complained directly yet but I am pretty sure people can hear it.
posted by Kitchen Witch at 3:25 AM on June 5, 2020


At least wait for people to complain before you unplug the fridge.
posted by mskyle at 3:41 AM on June 5, 2020 [27 favorites]


Long-term, get it fixed. Short term, do whatever you can to ease the air flowing around things, but leave it on. If you have Covid-19 your neighbours should cut you some slack.
posted by StephenB at 4:18 AM on June 5, 2020


Guidelines for food safety during power outages all seem to say 4 hours with the door closed.

CDC

FDA

The main thing is that the temperature can't be above 40f for 4 hours. You could put ice packs in the freezer, freeze them, then move them to the fridge before you unplug it. That would extend the time.
posted by Gorgik at 4:30 AM on June 5, 2020 [3 favorites]


Energy consumption of a typical fridge is about 1kWh of electrical energy per day. If we make the simplifying assumption that the compressor will be cycling on multiple times per hour, we can estimate the amount of electrical energy a fridge would miss out on by leaving it off for five hours as 1kWh * 5/24 = about 0.2kWh.

If we're generous about the quality of the compressor and assume that it has a coefficient of performance of about 5, that means the amount of thermal energy that would normally be removed from the interior over those five hours would come to 0.2kWh * 5 = 1kWh ~= 4MWs = 4MJ.

The latent heat of fusion for ice is 334kJ/kg. So to soak up 4MJ of thermal energy while keeping the temperature of the melt zone locked at 0°C requires 4MJ/(334kJ/kg) ~= 10kg of ice.

A kilogram of water is about a litre. So if you fill five 2-litre plastic milk bottles full of water, and freeze them (leave a little air gap in the bottles to reduce the extent to which the ice will stretch them as it freezes), then move them from the freezer compartment to the fridge compartment just before you turn off the power for the night, then at the end of the five hours your fridge interior should actually end up slightly colder than it would have been if you'd done nothing at all.

Whenever you turn the fridge back on again, move the bottles back into the freezer. If there still seems to be plenty of ice inside them, leave one in the fridge; keep reducing the number of bottles shuttling between fridge and freezer each day until you're seeing at least one of the shuttled bottles mostly melt. This will tell you how many bottles you actually need to be using for this.

This process will cost you a bit of storage capacity but almost no extra electricity, since all you're doing is time-shifting the fridge's peak consumption; you're not altering its interior temperature enough to make a significant difference to the total amount of heat it sucks in through its walls over the course of 24 hours. In fact, if you find yourself an electricity retailer who offers a discounted rate during times of lower demand, you might want to keep doing this even after your landlord fixes the buzz, tailoring your fridge's consumption profile in a way that saves you money.
posted by flabdablet at 4:47 AM on June 5, 2020 [9 favorites]


Alternatively, the first time you do this you can just leave the bottles in place in the fridge compartment and the fridge deprived of power until they do mostly melt. This will tell you how long five pre-frozen bottles will stabilize the fridge temperature for, and then you can scale the number of shuttled bottles as required to get you your five hours.
posted by flabdablet at 4:58 AM on June 5, 2020


Also, just to be clear: if you have a two litre bottle containing any ice, and the rest of what's in it is meltwater, and there isn't a lot of heat being applied via the air around it, then the temperature of that meltwater and that of the immediately surrounding air is going to be so close to 0°C as not to matter.

Since the interior of a fridge is generally supposed to sit somewhere a bit above freezing but under 5°C, then as long as you've still got some ice in your melt bottles you can be confident that your fridge contents are as safe from spoilage as they would be with the power on.
posted by flabdablet at 5:09 AM on June 5, 2020


Hey!

My fridge was doing this. It was an LG Fridge. Fixing things like this aren't too bad - here's a post of how I did it.

https://www.reddit.com/r/DIY/comments/detqu3/i_figured_out_what_was_wrong_with_my_noise_fridge/
posted by bbqturtle at 5:46 AM on June 5, 2020 [3 favorites]


Nthing that 5 hours is pushing it unless you have a bunch of ice in it to keep the temperature in the safe zone.
posted by Candleman at 7:54 AM on June 5, 2020


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