Energy savings of a ' fridge

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Richard J Kinch wrote:

Heat loss is heat loss -- all the other factors are simply changing the amount of same by either the same amount where something can be controlled well (as in a fixed weight of same items) or not so nearly the same as in more difficult to control (or at least much more expensive to develop test environments) of the door-opening that you seem so hung up over.
Again, it doesn't make any difference. It will change the absolute values, yes, but have very little bearing on the relatives...
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dpb writes:

That's naive. Performance depends on the design, which varies for cooling room air, versus wall conduction losses, making ice, defrosting, etc. Efficiency has more to do with those parameters than any basic heat pump efficiency. That model A is better than B for the few modes tested by the DOE, does not mean that A beats B for other modes.
Indeed, the opposite is quite to be expected, since the design will be optimized to the DOE fantasy test, which appears on a big yellow immunized sticker, rather than performance under real conditions, which most consumers never measure. You know, putting stuff inside, making ice, opening the door. The DOE test forces designs that idle cheaply, rather than ones that cheaply recover from intrusions, defrost, or chill or freeze contents.
Quite typically the ultra-efficient designs get the last bit of efficiency from complex mechanisms that are the first to fail and fall-back, leaving you worse off.
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Richard J Kinch wrote:

Not really...heat goes from inside the box to outside and is kept there at some level.
The same amount of heat has to be transferred to cool N grams of water to make ice.
Again it would change the absolute numbers; unlikely to change rankings much at all.
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dpb writes:

Public schooled?
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Do you have evidence that it may be the inverse? Have you done any testing?
The test is not perfect, the circumstances are not the same as every household uses their fridge in a different manner, but overall, heat gain into a given volume insulated container has to be removed. If two boxes, one more insulated than the other sit side by side in a 70 degree room, the better insulated one will have less gain. So, measure it, put it on a yellow tag and you have some basis for comparison. Real use will vary if you open the door five times or fifty times a day, but the comparison of A to BE will still be reasonably close. Add five pounds of water to each and make ice. You still have to move the same number of calories to get the water from 50 to 0 or whatever.
If the yellow tag sates $50 per year, my use may be 20% more, but the model that says $150 per year is still going to be 17% to 22% more and that is all I need to know. "Look honey, this one is better insulated so we can save a whale for dinner." That's all I need to know no matter how detailed your proposed test is.
I bought a car that states 30 mpg on the sticker and I'm happy with the 25 that I get and expected. I knew that difference up front. I do, in fact, know that it is better than the cars with the 20 mpg sticker and not as good as the ones with the 35 mpg sticker.
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Edwin Pawlowski wrote:

No sense arguing with a person like that. He is never happy with anything. Typically person like that blame everything/everyone but himself. That Energuide sticker is a quick reference for comparing A to B no matter what. If you are so energy concious, look at your life style first.
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I think both sides of this argument have merit. The bottom line is, we really don't know how adding ice makers, a reasonably full load of food and opening and closing doors will affect the overall energy usage of the units. I would agree it's likely there is some corelation between the current energy test and how they will perform under more realistic conditions. I'd be surprised if the most efficient one suddenly became the most inefficient, but we really don't know.
I agree with Richard on one thing. That is the way they test them is not even close to how they are actually used. Unless I'm missing something, that means the stickers on all the doors showing the estimated annual energy used is not even close to accurate, as it's underestimated. And I would have to agree that it sure looks suspiciously like a way to fool consumers into thinking the new unit on the showroom floor is going to use less energy than it really does, which helps sell them. The tests were arrived at jointly between the EPA and the manufacturers and by having a test that is skewed helps the manufacturers sell units and helps the EPA by making it look like the Energy Star program is producing better results that it actually is.
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On Apr 17, 6:59am, snipped-for-privacy@optonline.net wrote:

Has anybody here read how the Energy Star test is done or what it tries to achieve. Years ago I found it and if I remember it simulated a family of 4 with doors opening up to 90f interior temp and doors not opened over 91f. Simulate it right, and it gets close even without food as the air must cool. Ive bought quite few 19cu ft friges, last year about 10, my tenants electric bills dropped about 10$ a month, my Kill a watt confirms usage on my new and old stuff. Sure you will likely pay more than ratings but comparing new to old, to the Energy Star units is pretty dramatic, If you look at all energy star tests there are 20% better units then gov average. Overall 50-75% savings over old units is a reality. I found I can beat the Yellow Tag with carefull use, my frige when tested with a KAW meter is as good as Sun Frost, which at the time was the most efficent with 6" of foam insulation, At .125 kwh I was paying under 5$ a month. Whats so hard to believe, ACs go to 20? seer, cfls save 75%, Boilers are up to 93-98%, 30 years ago few cared. Just 10 years ago my heating co would not recommend a condensing boiler because they felt there were reliability issues, now they do. If the tests were so far off it would be headline news. Doing your own test is easy with a Kill a Watt or other similar unit
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Yes, I did. Richard provided the link several days ago in one of his posts. That is the basis for most of what has been discussed here regarding the accuracy of the tests. Go back in his posts, find it and take a look. It says the tests are done with the doors closed, no food, no ice maker, etc.
Years ago I found it and if I remember it simulated

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On Apr 17, 8:27am, snipped-for-privacy@optonline.net wrote:

I think its the wrong refrence. Yesterday I saw at Energy Star stating doors open below 90 or 91f then tests were done doors closed. The true refrence has it stating family usage as well.
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On Apr 17, 8:27am, snipped-for-privacy@optonline.net wrote:

I emailed you a pdf of what I found.
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On Apr 17, 8:27am, snipped-for-privacy@optonline.net wrote:

Ok I found it, and find it extensive in overall testing. sec 3.3 and 4.1.2.3 refer to doors open. Also note test is up to 90f for a period. And 96 hours. I dont see a scam in the testing.
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My experience is that most fridges don't have icemakers, and modern ones with icemakers don't consume power like that unless people use immense amounts of ice.

Amount of electrical energy to pump a given amount of heat energy from indoors to outdoors is about 1/3 of the heat energy. Ideally the ratio is 3.41 divided by EER of the air conditioner. And heat energy output of a fridge is same as electrical energy consumption of the fridge, plus only a tiny bit more for heat coming out for items going in warmer than they are coming out - it's close enough to equal to the electrical energy going into the fridge.
Cost to pump the heat from indoors to outdoors is zero when outdoors is cool enough to not use an air conditioner.

- Don Klipstein ( snipped-for-privacy@misty.com)
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Don Klipstein writes:

That's true, at least for air conditioning serving a small delta T of indoors to outdoors. Not so efficient when delta T is many times larger, going from 0 deg F freezer to warm outdoors. Think about why heat pumps for home heating aren't used when it is the mirror image of refrigeration, with 0 deg F outside and room temp inside.

Conservation of energy of course applies. But if you consider the multiple heat cycles that exposed water in the freezer goes through (chill/freeze/sublimate/condense/freeze/defrost/evaporate/condense), you'll understand why the electric energy consumed per BTU spoils the 3:1 rule of thumb. And why it's not therefore in the DOE test.
You can easily prove this to yourself with a duty cycle meter on your refrigerator/freezer, and measuring while making and storing ice, versus icemaker off and no exposed ice. In my experience you go from running constantly while ice is being made to running quite intermittently when there is no icemaking or exposed ice. A puddle of liquid water in a freezer is like a campfire in there, pushing the temp towards 32 deg F when the freezer wants to shut off at 0 deg F.
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Then again...

That's about 0.25x4x10/12^3x62 = 0.36 pounds of ice, ie 1.7 Btu/day worth 0.002 cents per day (61 cents per year :-) at 10 cents/kWh with a COP of 3.

Nick
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You're quoting and responding to someone else's post, not mine.
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Your experience with ice makers is totally different than mine. I don't notice any difference in running time on mine when it's making ice versus when it's not. It's most certainly NOT running all the time when making ice. Good grief, the amount of water that's frozen over a period of about an hour and a half is very modest, maybe a cup or so. You can do the math, but clearly the heat contained in that small qty of water should not make any decent refrigerator run constantly.
Also, you vastly overestimate the sublimation effect. Sure, ice will SLOWLY sublimate. If I leave the ice maker full, unused and off, after maybe a month, the volume will diminish by 1/3. So, we're talking about what? A quart of extra ice it has to make in a month? Sure it uses some energy, but in the grand scheme of things, I don't see this being a big factor. How about all the foods one puts in the freezer that go in above room temp, like two quarts of soup? Isn't that what the freezer is there for and supposed to do? Yet making some ice is supposed to be a big factor?
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Noticing or not noticing isn't physics. One has to appreciate thermodynamics and the heat of fusion to understand why ice making is so much more energy intensive than making up heat losses through a well- insulated cabinet or warm air infiltration.

I haven't actually made any specific estimate, over or otherwise, but I suppose you mean to say that sublimation and the other wasteful phase changes inside a refrigerator-freezer are trivial, when if fact they are a major factor as evidenced by the need for frequent defrosting and the pivotal role that plays in efficiency.
The trickiness of all debate over efficiency is that you can call things like sublimation trivial that are indeed small, but then you're comparing them to things that have been optimized down to very near zero, like heat gain through insulation, which is what the DOE test measures, then the efficiency ratings based on near-zero effects are still completely spoiled by the comparatively large sublimation type effects that aren't in the DOE tests.
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Richard J Kinch wrote:

But heat removal is still heat removal as has been pointed out before -- it's only the source and the amount of heat required to be removed from the water to create an equivalent amount of ice is the same for equal amounts of water at the same initial conditions. So again, it would change the magnitude of the numbers, much less effect on the _relative_ results which is the point of the test.
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And of course You are the idiot paying 30 month for an old frige, Im paying 5-6 for a 19,5, you piss your time away BSn yourself with your fancy bs talk on thermodynamicraps, and you lian , still , to yo wife, you pay, I dont sucker. Since this conv started you wasted 5 bucks, keep talkin, Keep waistin, mr putz.
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