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How long does a freezer stay frozen when the power goes out?

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Re: How long does a freezer stay frozen when the power goes out?

#161

Post by Xylakant »

pengaru wrote: post #153
Xylakant wrote: post #139

Earlier quoted context omitted.

Water is not a good choice to optimize for this. Most energy from the ambient air gets consumed at the thawing point of the medium - 0 degrees for water. So water/ice will keep freezer at 0 degrees for longer, but that’s not an attractive goal for a freezer - you want some cooling medium that does the phase change at a colder temperature (adding copious amounts of salt to the water would go a long way) Professional c…

Yeah well, water is practically free, readily available, relatively benign if it leaks, and can be a hydrating life-saver in a pinch. So it's a pretty good option as something other than air.

Keep in mind that everything with some amount of sugar or salt has a thaw point below 0 degrees. Practically all of your food will have thawed by the point the ice melts - so you’re dumping a lot of energy into freezing water that will be mostly useless at the point disaster strikes.

Adding salt to your water will substantially lower the thawing point and it’s still cheap and widely available.

If you want to prep for cases when you need water you’d be better off keeping your freezer cold with a suitable medium and have a few 30liter buckets of water with some sort of additive that prevents spoilage (silver ions for example) or have some packs of bottled water around.

Re: How long does a freezer stay frozen when the power goes out?

#162

Post by sharken »

an-allen wrote: post #154

Hi. Actualexperience here... it depends on the ambient temperature and how much stuff is in said freezer. So heres a data point: Freezer: normal upper level refrigerator freezer chock full of frozen fish caught on holiday in Alaska. Place, Time: Houston, TX, Late Summer, Hurricane Igor just hit and knocked our power out for 14 days. Findings: We kept the freezer shut and at about 4-5 days the fish was noticeably thaw…

Good data point !

Maybe next time try it with a top loaded freezer instead and see what happens.

Sorry about the freezer, but it was in the interest of science.

Re: How long does a freezer stay frozen when the power goes out?

#163

Post by kelnos »

fortran77 wrote: post #39
jacknews wrote: post #11

You want the contents to remain BELOW 0C, not hovering at 0C while everything melts. You can do this by adding some salt-water bottles, which have a lower melting point, and will therefore absorb a lot of heat (heat of fusion) well below 0C. Eg add 250g salt/liter gives melting point of -18C. Of course you waste some space on useless salt water vs potable - maybe there are better alternatives, eg fruit juice? Milk? H…

Vodka.

Isn't the freezing temp of vodka too low? I've kept vodka in the freezer, and it never actually freezes. In order to get the benefit described during a power outage, you need something that will be frozen at normal freezer temps, but will melt before the food starts thawing.

Re: How long does a freezer stay frozen when the power goes out?

#164

Post by bacon_waffle »

OJFord wrote: post #151
bacon_waffle wrote: post #126

Earlier quoted context omitted.

Water has a much higher heat capacity than water, and obviously much higher density too. By filling freezer space with water, the thermal mass of the freezer goes up, and it will stay cold for longer in a power outage.

I think your second 'water' was meant to be 'air'?

Oops, yes...

Re: How long does a freezer stay frozen when the power goes out?

#165

Post by sjwright »

nikau wrote: post #152
contingencies wrote: post #59

It depends on the thermal mass of the contents, the effectiveness of the insulation, and the external ambient environmental temperature. In real world use, it also generally depends on (1) how frequently and for how long you open it, and (2) whether it's top-loading (efficient) versus front-loading (inefficient). Source: My venture custom designed and built a refrigeration circuit with autonomous electronic managemen…

> My venture custom designed and built a refrigeration circuit with autonomous electronic management Is that a web 2.0 way of saying a thermostat?

It's probably a web 3.0/IoT way of saying an ESP8266 with a couple of sensors and a relay. From there you could do some slightly smart stuff like observe the rate of warming towards ambient when idle (i.e. determine the volume of material in the freezer) to determine how long you can go without running the compressor. And from there you could manipulate the thermostat's target depending on current and future predicted electricity prices.

With a load sensor attached to the tub, you could determine when a substantial volume of new material has been added and preemptively run the compressor hard for a bit.

Many things are possible. Most of them not worth the complexity.

Re: How long does a freezer stay frozen when the power goes out?

#166

Post by xxs »

NegativeLatency wrote: post #117
Dylan16807 wrote: post #110

Earlier quoted context omitted.

Is the efficiency benefit bigger than getting a different model or taping some styrofoam to the outside of the fridge?

I’d hazard a guess that most of the losses are from when you open the door and the seal around the door. Also while cooler than ambient my fridge and freezer don’t feel cool to the touch so I think that the walls are thick enough. Otherwise fridges and freezers would ship with thicker insulation.

if they are cooler than ambient (cool on touch) - it'd cause condensation.

Re: How long does a freezer stay frozen when the power goes out?

#167

Post by toxik »

an-allen wrote: post #154

Hi. Actualexperience here... it depends on the ambient temperature and how much stuff is in said freezer. So heres a data point: Freezer: normal upper level refrigerator freezer chock full of frozen fish caught on holiday in Alaska. Place, Time: Houston, TX, Late Summer, Hurricane Igor just hit and knocked our power out for 14 days. Findings: We kept the freezer shut and at about 4-5 days the fish was noticeably thaw…

You missed the perhaps most important datapoint: how often and many times did you open the freezer? Side loaded freezer and fridges are extremely inefficient because all the cold air is let out when you open the door.

Re: How long does a freezer stay frozen when the power goes out?

#168

Post by amelius »

geofft wrote: post #92
morninglight wrote: post #64

The location of the freezer or refrigerator is critical. If you live in a house that has a typical unfinished basement, don't overlook the advantage it offers. With one simple change, you can noticeably lower your electric bill, reduce your carbon footprint, gain extra kitchen space and improve your health. Just move your refrigerator to the basement. Since the basement is normally cooler than the upstairs, the refri…

This seems like a decent idea if the thing that's in your fridge is ice cream, but not if it's ingredients for cooking meals. Whoever does the cooking is going to spend a ton of time running up and down while stuff overcooks, and then they'll be even more tired and get more complaints from the rest of the family. So you should be absolutely sure that you have an equitable family dynamic and that everyone agrees that…

Eh, just get all the stuff you need before you start cooking, and bring a bag if necessary.

Planning really isn't that difficult. People do it all the time when they go to the grocery store.

Re: How long does a freezer stay frozen when the power goes out?

#169

Post by berkes »

Arainach wrote: post #160
bryanrasmussen wrote: post #155

Earlier quoted context omitted.

Not to argue with science but why didn't you clean the fish out about day 7? Was it hurricane made getting rid of fish problematic?

If the power infrastructure hasn't been restored yet, what are the odds of trash being collected? The freezer at least contains the smell a bit. That fish outdoors in the heat could start smelling even worse.

If you have even the smallest patch of ground, dig a small hole, drop the dead animals/spoiled meat in there, and the smell is gone within minutes.

My experience comes from living countryside with two cats dragging in rabbits, rats, pheasants and two/three daily mice and birds in. My cats prefer cat-food, so they drag in the dead animals, tuck it under the couch or behind the fridge, and then eat their favorite chunks, the assholes.

Throwing it on the compost heap smells way worse and attracts flies. than digging a ~3cm deep hole and covering it. A mouse under the ground, is gone in less than a week (I guess its eaten by worms and insects mostly). My garden is doing very well.

Re: How long does a freezer stay frozen when the power goes out?

#170

Post by Xylakant »

jjulius wrote: post #116
em-bee wrote: post #98

Earlier quoted context omitted.

you'll learn to plan your meals better. take everything out that you need before you start...

"Refrigerate X while cooking Y, then remove X from fridge as Y begins to [something]," and variants of that phrase are common scenarios in recipes. Your point is only valid for a portion of recipes, not all. Let's also take into account how many ingredients you may need from the fridge when you plan ahead. Certain meals may require multiple trips to/from the basement (however far away that may be) depending on how ma…

Very few recipes involve taking stuff from the freezer repeatedly however, most things will need to thaw in advance. Making ice cream in a freezer in the basement would suck, however.

Not having the fridge readily available in the kitchen would suck, though, so that only works if you have a dedicated freezer.

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