Does keeping ice packs in fridge save energy?

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Caduceus
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Does keeping ice packs in fridge save energy?

Post by Caduceus »

I get these ice packs that are filled with some type of gel or liquid type substance with my deliveries when the ordered items need to be kept cold. I have ended up getting quite a lot of them. So what I am wondering is, if every now and then, I transfer them out of the freezer (they get rock hard in the freezer) into the fridge, does it actually save some energy by keeping my fridge cooler than it would otherwise be and using less energy?
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Re: Does keeping ice packs in fridge save energy?

Post by Tellurius »

You will refreeze them later, no? That will take more energy in total (unfreeze then refreeze) than just leaving them frozen.
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Re: Does keeping ice packs in fridge save energy?

Post by DoTheMath »

From another perspective, you're transferring heat from the fridge to the freezer.
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Re: Does keeping ice packs in fridge save energy?

Post by Beach »

I keep a gallon of water in my bulk freezer. I figure, if we have an extended power outage it might help keep it cooler longer. No idea if it saves energy, not really concerned
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Re: Does keeping ice packs in fridge save energy?

Post by LilyFleur »

Keeping your freezer full helps save on energy costs.

https://home.howstuffworks.com/freezer- ... y-tips.htm
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Re: Does keeping ice packs in fridge save energy?

Post by cheese_breath »

Just not so full that the air can't circulate to all the foods.
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Re: Does keeping ice packs in fridge save energy?

Post by cheese_breath »

Don't throw them all out. Keep some in the freezer in case you need some ice packs for an injury.
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Re: Does keeping ice packs in fridge save energy?

Post by Swivelguy »

There's no free lunch and definitely no free energy. Spending energy to freeze them in the freezer in order to spend less energy in the fridge can't result in coming out ahead. Moving them between fridge and freezer probably wastes some energy, but mostly because you're opening the doors and moving objects around for no reason. It also wastes your time, effort, and freezer/fridge space.

Keeping some in either the fridge or freezer and NOT moving them will make them slightly more efficient (because there's less exchange of air when you open the door), and doesn't really cost any effort, but still costs space.
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ResearchMed
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Re: Does keeping ice packs in fridge save energy?

Post by ResearchMed »

cheese_breath wrote: Thu May 07, 2020 4:38 pm Don't throw them all out. Keep some in the freezer in case you need some ice packs for an injury.
Unless the gel packs are very small, you might want to shape a few into a bit of a curve, if you might want them for an injury. And yes, they can come in handy. (So can a nice pliable package of frozen peas, in an emergency!)

That way, if you have an injury on a regular human body part (e.g., ankle, shoulder), you won't be trying to cool it with a cold flat-sided brick.

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Re: Does keeping ice packs in fridge save energy?

Post by adamthesmythe »

You need to know whether your refrigerator or the freezer is more efficient to decide.

In any case I expect the effect to be negligible (and depending on relative efficiencies, it could be positive or negative).
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Re: Does keeping ice packs in fridge save energy?

Post by rkhusky »

I’ve wondered in the winter whether to freeze a couple gallons of water outside and then put them in the fridge. But never got around to it.
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Re: Does keeping ice packs in fridge save energy?

Post by bob60014 »

LilyFleur wrote: Thu May 07, 2020 4:20 pm Keeping your freezer full helps save on energy costs.

https://home.howstuffworks.com/freezer- ... y-tips.htm
+1, This is the correct answer.
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Re: Does keeping ice packs in fridge save energy?

Post by barnaclebob »

rkhusky wrote: Thu May 07, 2020 5:16 pm I’ve wondered in the winter whether to freeze a couple gallons of water outside and then put them in the fridge. But never got around to it.
That might be a complicated answer because the less your fridge cycles in winter, the more heat your hvac will have to supply. But just about all forms of heat are cheaper than electicity so as long as you have gas or oil heat then its probably a net benefit.
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Re: Does keeping ice packs in fridge save energy?

Post by rkhusky »

barnaclebob wrote: Thu May 07, 2020 5:51 pm
rkhusky wrote: Thu May 07, 2020 5:16 pm I’ve wondered in the winter whether to freeze a couple gallons of water outside and then put them in the fridge. But never got around to it.
That might be a complicated answer because the less your fridge cycles in winter, the more heat your hvac will have to supply. But just about all forms of heat are cheaper than electicity so as long as you have gas or oil heat then its probably a net benefit.
Plus the ice would take up room. I have a Watt Meter so I could actually test things. But I imagine the savings would be small so haven’t been motivated.
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Re: Does keeping ice packs in fridge save energy?

Post by 123 »

I have heard that having empty space in the refrigerator or freezer causes energy usage to be higher so we store some gallon jugs of water in the refrigerator and ice packs in the freezer in space that would otherwise be empty. They should help to maintain established temperature in the event of a power outage. If we need more space, like for a Thanksgiving turkey, we take them out as needed.
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Re: Does keeping ice packs in fridge save energy?

Post by ram »

I keep 2 gallon of water in my deep freezer, not to save energy but to extend the freezer effect if I lose electricity for a few hours.
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Re: Does keeping ice packs in fridge save energy?

Post by badbreath »

Will the ice packs help in a power outage? No not really since the refrigerator relies on a cold air circulating from the freezer which uses dampers and fans which need electricity.
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Re: Does keeping ice packs in fridge save energy?

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Re: Does keeping ice packs in fridge save energy?

Post by IMO »

What can save money during the summer months is to freeze small plastic bottles and use them for your coolers (without otherwise having to deplete all your ice). Buying ice is very expensive. Even better, freeze some drinks that can be frozen (such as gatorades) and use those for dual purpose in the cooler saving space in your cooler.
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Re: Does keeping ice packs in fridge save energy?

Post by TSR »

Counterpoint: Modern day refrigerators use astonishingly less energy than they used to, maybe 350 kWh/year. Any of these efforts would likely have only a marginal financial benefit if any. I'm all for efficiency and making personal sacrifices to achieve such efficiencies, but it is likely that there are better uses of those admirable efforts.
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Re: Does keeping ice packs in fridge save energy?

Post by Afty »

TSR wrote: Fri May 08, 2020 1:06 pm Counterpoint: Modern day refrigerators use astonishingly less energy than they used to, maybe 350 kWh/year. Any of these efforts would likely have only a marginal financial benefit if any. I'm all for efficiency and making personal sacrifices to achieve such efficiencies, but it is likely that there are better uses of those admirable efforts.
I was thinking about this as well. Somewhat arbitrarily, I picked the best selling refrigerator/freezer combo on BestBuy.com. According to its Energy Guide label, it uses ~400 kWh/yr. At a relatively expensive electric rate of $0.20/kWh, that's $80/yr. Maybe you could save 20% of that, or $16, by various tricks? Doesn't seem worth the effort.
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Re: Does keeping ice packs in fridge save energy?

Post by marc in merrimack »

TSR wrote: Fri May 08, 2020 1:06 pm Counterpoint: Modern day refrigerators use astonishingly less energy than they used to, maybe 350 kWh/year. Any of these efforts would likely have only a marginal financial benefit if any. I'm all for efficiency and making personal sacrifices to achieve such efficiencies, but it is likely that there are better uses of those admirable efforts.
It’s hardly a personal sacrifice to incorporate some thermal mass in otherwise unused refrigerator and freezer space.
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Re: Does keeping ice packs in fridge save energy?

Post by TSR »

marcwd wrote: Fri May 08, 2020 2:29 pm
TSR wrote: Fri May 08, 2020 1:06 pm Counterpoint: Modern day refrigerators use astonishingly less energy than they used to, maybe 350 kWh/year. Any of these efforts would likely have only a marginal financial benefit if any. I'm all for efficiency and making personal sacrifices to achieve such efficiencies, but it is likely that there are better uses of those admirable efforts.
It’s hardly a personal sacrifice to incorporate some thermal mass in otherwise unused refrigerator and freezer space.
I agree. To be clear, I generally toss ice-packs into the freezer and leave them there when I get them. I comfort myself with the knowledge that they're probably increasing the efficiency a bit. I just don't think it would have a serious effect on the bottom line, either for energy efficiency or the power bill.
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Re: Does keeping ice packs in fridge save energy?

Post by marc in merrimack »

TSR wrote: Fri May 08, 2020 2:42 pm
marcwd wrote: Fri May 08, 2020 2:29 pm
TSR wrote: Fri May 08, 2020 1:06 pm Counterpoint: Modern day refrigerators use astonishingly less energy than they used to, maybe 350 kWh/year. Any of these efforts would likely have only a marginal financial benefit if any. I'm all for efficiency and making personal sacrifices to achieve such efficiencies, but it is likely that there are better uses of those admirable efforts.
It’s hardly a personal sacrifice to incorporate some thermal mass in otherwise unused refrigerator and freezer space.
I agree. To be clear, I generally toss ice-packs into the freezer and leave them there when I get them. I comfort myself with the knowledge that they're probably increasing the efficiency a bit. I just don't think it would have a serious effect on the bottom line, either for energy efficiency or the power bill.
It’s not a matter of energy efficiency or the power bill, but rather a means of helping stabilize the temperature in a climate controlled space. And in the event of a power failure, this can be a distinct benefit.
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Re: Does keeping ice packs in fridge save energy?

Post by bacon4retirement »

No energy savings from shuffling ice packs at random times, and in fact, an energy loss by opening the door for a longer period.

However, you might be able to save money by swapping the ice packs at the right times. If your utility has a time-of-use electricity rate, your power might cost much less overnight than during the day. Moving the ice packs into the freezer every night and into the fridge in the morning would shift a small amount electrical consumption into the cheaper overnight hours. As noted above, modern refrigerators are highly efficient, so there isn't much money to save.

Swapping ice packs at the right times method might also save energy if your home has air conditioning, and there is large difference between daytime and nighttime outdoor ambient temperatures. All the heat produced by the refrigerator also has to be removed from the house the the AC. Running the refrigerator more at night would put slightly burden on the household air conditioning. In most climates, I doubt the increased air conditioning efficiency would make up for the energy loss from opening the doors.

Some buildings use ice makers to shift peak air conditioning loads from the afternoon to overnight hours. An example is described at https://www.altenergymag.com/article/20 ... tery/23515.
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Re: Does keeping ice packs in fridge save energy?

Post by TomatoTomahto »

Oh my goodness, maybe this thread is a sign that we’ve been quarantined for a really long time.

No offense intended, OP. Btw, I always make sure my fridge and freezer don’t have excessive empty space, as I have read that trying to cool air is inefficient.
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Re: Does keeping ice packs in fridge save energy?

Post by Cubicle »

So to add a little fuel to the fire, would it make sense to freeze ice packs in a deep freezer than transfer them to the refrigerator? A deep freezer has no fridge portion. It's only mission is to maintain a freezing temperature. And the ones I've been around have better insulation. As a one trick pony, I think it can freeze water with slightly less wasted energy.

Or maybe I'm extremely wrong.
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Re: Does keeping ice packs in fridge save energy?

Post by jharkin »

Caduceus wrote: Thu May 07, 2020 4:13 pm I get these ice packs that are filled with some type of gel or liquid type substance with my deliveries when the ordered items need to be kept cold. I have ended up getting quite a lot of them. So what I am wondering is, if every now and then, I transfer them out of the freezer (they get rock hard in the freezer) into the fridge, does it actually save some energy by keeping my fridge cooler than it would otherwise be and using less energy?
No. It took energy to freeze them in the first place. As a matter of fact, this method is probably more expensive as the efficiency of a refrigerant cycle decreases as the delta-T increases (difference betwen inside and outside temp).. ie the freezer section (65-80 degree delta to room) costs more to operate for each degree of cooling than the fridge (30-40 delta).

And then there are the door opening losses mentioned above as well...

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Re: Does keeping ice packs in fridge save energy?

Post by mediahound »

I came here searching for an answer but am still wondering,

If the ice packs arrive to me frozen, and then I put them in the fridge and let them thaw there before disposing of them, isn't that a bit of free cold energy for my fridge? Or does it overly tax the fridge or something like that?
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Re: Does keeping ice packs in fridge save energy?

Post by gunny2 »

LilyFleur wrote: Thu May 07, 2020 4:20 pm Keeping your freezer full helps save on energy costs.
Same with the fridge. Living alone, I don't need either to be full, so I have things like gallon jugs of water to take up space.
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Re: Does keeping ice packs in fridge save energy?

Post by chinchin »

mediahound wrote: Sun Mar 31, 2024 10:09 pm I came here searching for an answer but am still wondering,

If the ice packs arrive to me frozen, and then I put them in the fridge and let them thaw there before disposing of them, isn't that a bit of free cold energy for my fridge? Or does it overly tax the fridge or something like that?
You’re adding heat to the fridge by opening the door (once to put the pack in once to take it out).
not financial advice
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Re: Does keeping ice packs in fridge save energy?

Post by mediahound »

chinchin wrote: Sun Mar 31, 2024 10:32 pm
mediahound wrote: Sun Mar 31, 2024 10:09 pm I came here searching for an answer but am still wondering,

If the ice packs arrive to me frozen, and then I put them in the fridge and let them thaw there before disposing of them, isn't that a bit of free cold energy for my fridge? Or does it overly tax the fridge or something like that?
You’re adding heat to the fridge by opening the door (once to put the pack in once to take it out).
But what if I put the ice packs in there at the same time I’m putting food in the fridge?
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Re: Does keeping ice packs in fridge save energy?

Post by chinchin »

mediahound wrote: Sun Mar 31, 2024 10:33 pm
chinchin wrote: Sun Mar 31, 2024 10:32 pm
mediahound wrote: Sun Mar 31, 2024 10:09 pm I came here searching for an answer but am still wondering,

If the ice packs arrive to me frozen, and then I put them in the fridge and let them thaw there before disposing of them, isn't that a bit of free cold energy for my fridge? Or does it overly tax the fridge or something like that?
You’re adding heat to the fridge by opening the door (once to put the pack in once to take it out).
But what if I put the ice packs in there at the same time I’m putting food in the fridge?
Unless you are good at juggling it is probably taking you more time to open and close the door compared to if you were not trying to shove ice packs in and out of the fridge.
not financial advice
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Re: Does keeping ice packs in fridge save energy?

Post by Jeepergeo »

It provides thermal mass which should help moderate swings in temperature, which should reduce your freezer and refrigerator run times and thus energy. A lot depends on how often you open and close the doors and how long you keep the doors open, and if you put hot, warm, or pre-cooled items inside.

I use milk jugs filled with water. They serve as an emergency water supply and are easy to arrange in the freezer when needed and to remove them when space is needed.
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Re: Does keeping ice packs in fridge save energy?

Post by mediahound »

Jeepergeo wrote: Sun Mar 31, 2024 10:55 pm It provides thermal mass which should help moderate swings in temperature, which should reduce your freezer and refrigerator run times and thus energy. A lot depends on how often you open and close the doors and how long you keep the doors open, and if you put hot, warm, or pre-cooled items inside.

I use milk jugs filled with water. They serve as an emergency water supply and are easy to arrange in the freezer when needed and to remove them when space is needed.
Mainly, I just can't fathom that letting the ice packs thaw in the fridge until they are liquid versus just out at room temp. would be the same in terms of energy usage. I feel like there is some free thermal energy in them to be captured if I wasn't the one who froze them.
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Re: Does keeping ice packs in fridge save energy?

Post by tetractys »

Caduceus wrote: Thu May 07, 2020 4:13 pm I get these ice packs that are filled with some type of gel or liquid type substance with my deliveries when the ordered items need to be kept cold. I have ended up getting quite a lot of them. So what I am wondering is, if every now and then, I transfer them out of the freezer (they get rock hard in the freezer) into the fridge, does it actually save some energy by keeping my fridge cooler than it would otherwise be and using less energy?
No due to conservation of energy; but it will keep your refer cooler longer if the power goes out.
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Re: Does keeping ice packs in fridge save energy?

Post by andypanda »

We have a top freezer. Ever open the freezer door and feel the cold air falling on your feet? I have. You paid to chill that air and it's escaping. Now you get to pay to chill the warm air you let in.

Less air space in the freezer and more frozen water jugs, gel packs, or Arctic Ice packs means less cold air falling out. I fish a lot, go to the beach a lot and I'm the one in charge of cold coolers for trips, ball games and lunches. I keep the freezer as full as I can.

I use Arctic Ice Alaskan Series packs from palm-sized up to 5 pounds. I used to use gel packs that came in my parents' med shipments, but they wear out and leak in the cooler sooner or later.

Ice in the freezer does help keep the food frozen during our regular extended power outages. Falling trees and limbs. We're on a circuit with 1200 customers along the river in the woods, so they get to us fairly quickly, but sometimes it's multiple trees.
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Re: Does keeping ice packs in fridge save energy?

Post by dodecahedron »

I have a deliberately chosen fridge/freezer intended for apartment use because my household is small (just 2 of us) and it uses minimal energy because no bells and whistles like ice maker or chilled water dispenser. I generally keep freezer naturally pretty full and I like to keep it well stocked with variety of frozen fruits and vegetables that I opportunistically stock up on on sale. At any given time, I generally have one or two frozen things thawing in the fridge. No need or room for ice packs.
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Re: Does keeping ice packs in fridge save energy?

Post by eigenperson »

mediahound wrote: Sun Mar 31, 2024 11:02 pm
Jeepergeo wrote: Sun Mar 31, 2024 10:55 pm It provides thermal mass which should help moderate swings in temperature, which should reduce your freezer and refrigerator run times and thus energy. A lot depends on how often you open and close the doors and how long you keep the doors open, and if you put hot, warm, or pre-cooled items inside.

I use milk jugs filled with water. They serve as an emergency water supply and are easy to arrange in the freezer when needed and to remove them when space is needed.
Mainly, I just can't fathom that letting the ice packs thaw in the fridge until they are liquid versus just out at room temp. would be the same in terms of energy usage. I feel like there is some free thermal energy in them to be captured if I wasn't the one who froze them.
There is.

I don't know exactly what is in the ice packs, but if it's pure water ice at 0 degrees, it will absorb about 340 J of heat per gram. Fully replacing 20 cubic feet of cold air with room-temperature air costs you about 10,000 J to replace. So if your fridge is 20 cubic feet or so, and you are adding more than roughly 30 grams of ice to your fridge, it's worth putting the ice in even though you let the cold air out.

On the other hand, if your air conditioner is running, the ice left out on the counter will cool your house and let it stop a little earlier, so the energy isn't wasted in either location.
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Re: Does keeping ice packs in fridge save energy?

Post by obgraham »

As snowbirds, we will be heading North soon, so we are eating our way through the freezer contents. I don't run that freezer when we leave. As my chest freezer is now only about 1/4 full I've noticed that the temperature runs mostly about -1 to +2, whereas when it was full it was usually at -11 or so.

So yes, the greater air volume reduces the efficiency of the freezer. In the long run, best to keep it full, frozen jugs if need be.
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Re: Does keeping ice packs in fridge save energy?

Post by nisiprius »

ResearchMed wrote: Thu May 07, 2020 4:56 pm (So can a nice pliable package of frozen peas, in an emergency!)
Frozen peas, or other frozen vegetables, are our go-to. Absolutely.

(In 2024 I don't think I need to specify "the kind individually frozen and packed in bags," as the solid-brick kind have gotten rare.).
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Re: Does keeping ice packs in fridge save energy?

Post by calmaniac »

Caduceus wrote: Thu May 07, 2020 4:13 pm I get these ice packs that are filled with some type of gel or liquid type substance with my deliveries when the ordered items need to be kept cold. I have ended up getting quite a lot of them. So what I am wondering is, if every now and then, I transfer them out of the freezer (they get rock hard in the freezer) into the fridge, does it actually save some energy by keeping my fridge cooler than it would otherwise be and using less energy?
No. That violates the First Law of Thermodynamics, which states that "the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed".

If that were the case, you could cycle the packs back and forth from frig to freezer and essentially create a perpetual motion (cooling) machine. Moving the freezer pack does not change the amount of energy in the closed system.
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Re: Does keeping ice packs in fridge save energy?

Post by rkhusky »

I’ve wondered if in winter I should put some water jugs outside, let them freeze, and then put them in the fridge or freezer.
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Re: Does keeping ice packs in fridge save energy?

Post by andypanda »

"(In 2024 I don't think I need to specify "the kind individually frozen and packed in bags," as the solid-brick kind have gotten rare.)."

Bird's Eye and Green Giant still make boxes. Walmart has them here. They stack better than the bags.
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Re: Does keeping ice packs in fridge save energy?

Post by Riprap »

Does keeping ice packs in fridge save energy? (Please explain, show all work)

Sounds like a question from a thermodynamics course final exam.
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Re: Does keeping ice packs in fridge save energy?

Post by lthenderson »

calmaniac wrote: Mon Apr 01, 2024 9:09 pm No. That violates the First Law of Thermodynamics, which states that "the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed".
+1

Otherwise you would have single handedly produced the first unlimited clean energy source!
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Re: Does keeping ice packs in fridge save energy?

Post by mediahound »

So what is the bottom line? If I'm going to dispose of some ice packs that were delivered to me already frozen. Should I thaw them out at room temperature first or thaw them in the fridge?
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Re: Does keeping ice packs in fridge save energy?

Post by David Jay »

mediahound wrote: Tue Apr 02, 2024 9:24 am So what is the bottom line? If I'm going to dispose of some ice packs that were delivered to me already frozen. Should I thaw them out at room temperature first or thaw them in the fridge?
If you receive ice packs regularly and thaw them in the fridge you will gain a fraction of a penny in energy savings over the course of your entire lifetime.
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Re: Does keeping ice packs in fridge save energy?

Post by eigenperson »

rkhusky wrote: Mon Apr 01, 2024 10:07 pm I’ve wondered if in winter I should put some water jugs outside, let them freeze, and then put them in the fridge or freezer.
No, don't bring cold stuff into your house in winter. Your fridge will run less, but your heater will run more to compensate.
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Re: Does keeping ice packs in fridge save energy?

Post by rkhusky »

eigenperson wrote: Tue Apr 02, 2024 9:34 am
rkhusky wrote: Mon Apr 01, 2024 10:07 pm I’ve wondered if in winter I should put some water jugs outside, let them freeze, and then put them in the fridge or freezer.
No, don't bring cold stuff into your house in winter. Your fridge will run less, but your heater will run more to compensate.
But in our area electricity is more expensive than natural gas.
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