Question for the physics gurus

[fasternyou929]

Originally Posted by EpyonXero

Once the items in the freezer are at a stable temperature the freezer will use less energy than an empty freezer because air loses heat faster than most food items.

Did you notice you contradicted yourself there? If air loses heat faster than food items, air (an empty freezer) would be the most efficient scenario.

Originally Posted by EpyonXero

Putting jugs of water in an empty or almost empty freezer will cause the freezer to do more work in order to cool the water if the power were to go out the freezer would remain colder longer because it takes more energy to heat water than air. However, if your freezer is full adding water isnt necessary because the food will keep each other cool.

If a package of ground beef is chilled to 0F and placed in a freezer where the air temp is 0F, how do you suppose ground beef is going to generate heat? Remember, in thermodynamics there's no such thing as "cold", just loss or addition of heat. For food to make the freezer less effective it would need to generate heat.

Food, water, etc. can not "keep each other cool".

[Adeptus_Minor]

Originally Posted by fasternyou929

If a package of ground beef is chilled to 0F and placed in a freezer where the air temp is 0F, how do you suppose ground beef is going to generate heat? Remember, in thermodynamics there's no such thing as "cold", just loss or addition of heat. For food to make the freezer less effective it would need to generate heat.

You know, I did have this idea for endothermic food.
Most food, when metabolized, is used to generate heat... but what about a food that actually cooled you off when you ate it?

Bah, it'd probably make you fat or cause cancer anyway.

[Homeslice]

Originally Posted by fasternyou929

Food, water, etc. can not "keep each other cool".

Except if the power goes out

Or if you are buying groceries and put the frozen food together so that it doesn't thaw while you're driving home

[101lifts2]

Originally Posted by EpyonXero

Once the items in the freezer are at a stable temperature the freezer will use less energy than an empty freezer because air loses heat faster than most food items.....

Its a non-living item meaning it will not produce chemical reactions causing heat. Once the items are at the same temperature as the freezer they will remain. Same goes with the air. The energy to maintain the temp is the same unless the frig has huge leaks in the weatherstripping.

[fasternyou929]

Originally Posted by Homeslice

Except if the power goes out

still not true unless you open the freezer. But that scenario is not the original question and has zero impact on a freezer's efficiency.

[Homeslice]

Originally Posted by fasternyou929

still not true unless you open the freezer.

Even if you don't, solids and liquids are more dense than gases, with more molecules per sq inch........Therefore they can act as a better heat absorber, to protect against invading heat once the power goes out.

I got the tip about putting jugs of water in the freezer from the power company, I think they know what's up

[EpyonXero]

Originally Posted by fasternyou929

Did you notice you contradicted yourself there? If air loses heat faster than food items, air (an empty freezer) would be the most efficient scenario.

If a package of ground beef is chilled to 0F and placed in a freezer where the air temp is 0F, how do you suppose ground beef is going to generate heat? Remember, in thermodynamics there's no such thing as "cold", just loss or addition of heat. For food to make the freezer less effective it would need to generate heat.

Food, water, etc. can not "keep each other cool".

(sigh)

Its not a contradiction at all. If your goal is to make a freezer cold as fast as possible then an empty one would be the most efficient because, as I said, air loses heat quickly. But, if you want your freezer to stay cold when the power goes out and run more efficiently then a full freezer is better. The property that makes air fast to cool also makes it quick to lose heat though the freezer walls.

I dont know why you think I said anything would generate heat. Im talking about putting food or a jug of water, which obviously isnt frozen yet, into a freezer. Obviously adding a jug of liquid water to a freezer will raise the temperature of the system and cause the freezer to work to cool it until it reaches whatever the temperature the thermostat is set at. The freezer wants a constant temperature, anytime you alter that it causes the freezer to do more work.

The more mass in a system that needs to be heated the longer it will take for that system to increase in temperature for a given amount of heat transfer. This is why food and water in a full freezer can keep each other cool. If that wasnt the case, then nobody would bother putting ice on things that are already frozen.

[fasternyou929]

Originally Posted by EpyonXero

(sigh)

Its not a contradiction at all. If your goal is to make a freezer cold as fast as possible then an empty one would be the most efficient because, as I said, air loses heat quickly. But, if you want your freezer to stay cold when the power goes out and run more efficiently then a full freezer is better. The property that makes air fast to cool also makes it quick to lose heat though the freezer walls.

Sigh is right.

You keep bringing up "when the power goes out" and for the last time, you're right. I agree with you. Spot on!

I was talking strictly about the efficiency of a closed system, and it's not affected by adding or subtracing food. Unless, like you said, you put in food/liquid that the system needs to work to cool.

[EpyonXero]

Originally Posted by fasternyou929

Sigh is right.

You keep bringing up "when the power goes out" and for the last time, you're right. I agree with you. Spot on!

I was talking strictly about the efficiency of a closed system, and it's not affected by adding or subtracing food. Unless, like you said, you put in food/liquid that the system needs to work to cool.

Look, my response was to the original question which is about a real freezer and not a closed system.

[askmrjesus]

Originally Posted by fasternyou929

Food, water, etc. can not "keep each other cool".

Bullshit!

It happens all time.

Cantaloupe: I'm going to fuck me some bacon!

Eggs: Back off the bacon, melon boy!

Mayo: brumgble!

Ketchup: What?

Mayo: BRUMBGLE!

Ketchup: You're fucking high.

Potatoes: Don't make me come outta this drawer, I will fuck you up.

Sour cream: Yeah!

JC