182. SUPER-EFFICIENT CHEST FRIDGE
One of the basic principles of sustainability guru Amory Lovins’ idea of Natural Capitalism is that almost everything in the modern world is so appallingly designed that getting dozens of times more productivity out of the same raw materials should not be very hard. A great demonstration of this is the refrigerator, or more specifically, this refrigerator:
Its creator, an off-the-grid experimenter from Australia named Tom Chalko, realised that since cold air is heavier than warm air, when you open the door of a traditional vertical fridge all the cold air simply falls out. On the other hand, the horizontal chest freezers you see in supermarkets can basically be left wide open because cold air does not travel upwards. He bought a chest freezer for a few hundred dollars and fitted it with a thermostat to make it run at the temperature of a fridge. It runs for about 2 minutes an hour and then turns off, thus using about 100 watt-hours per day, or less than one-tenth that of a standard fridge. Here’s what the inventor says about it:
“The biggest limitations are our habits and mediocre attitudes, not technology or cost … It is obvious that a truly energy efficient fridge does not cost any more money than a mediocre one. It actually costs less. It also has extra features, such as digital temperature display that gives you full control on the temperature settings inside. Nearly every household on Earth has a fridge that totally wastes at least 1 kWh of energy a day (365 kWh a year).” (Source: http://www.builditsolar.com/Projects/Conservation/chest_fridge.pdf and http://www.mtbest.net/chest_fridge.html).You can get instructions on how to make your own chest fridge here.
-- by Roland
posted by JD @ 5:04 PM
43 comments
43 Comments:
I wonder if there's a way to preserve the efficiency of a top-loading fridge while making it a little safer for kids. A child could get stuck in that thing.
If there's actually anything *in* the fridge, I find it hard to see how anyone taller than the fridge could fit. And obviously anyone shorter isn't going to be able to open it & climb in. (Which in a way makes it safer than a normal fridge.)
This reminds of a bit of political legend from George Bush Senior's presidency. The lame-butt was captured on network news marveling at a supermarket checkout scanner. He had never seen one. It seems that the guy was so pampered, so out of touch that he had never shopped in a supermarket. You know, the maid did that kind of work.
Well this has got to be in the same class. JD are you going to tell me that you never bought an ice cream pop from a candy store or corner market? Did you ever have a childhood or were your born a completely heartless machine? Were you raised in a cage with a terrycloth surrogate mother? THESE ARE CALLED CHEST FREEZERS. Google it. Trust me. It is about normal life outside the test tube.
The child-proof seal wouldn't work, unfortunately, unless the fridge could be opened from the inside without any difficulty. Refrigerators used to have latches and handles on them in olden days but they got removed because children would get stuck inside. :( The problem here is that a kid would have to be able to climb out of the fridge, rather than just stepping out as in the current design.
Maybe what we need is some kind of coolth catcher that picks up all the coolth (when you open the door) and blows it back into the fridge, where it belongs. :)
If there's actually anything *in* the fridge, I find it hard to see how anyone taller than the fridge could fit. And obviously anyone shorter isn't going to be able to open it & climb in. (Which in a way makes it safer than a normal fridge.)
What? You have got to be kidding me.
First of all, someone taller than the fridge could fit inside by lying down or by curling up into a little ball. Secondly, little kids can climb things that are taller than they are. They are ingenious at getting themselves into trouble. It's getting out of trouble that's hard.
"Well this has got to be in the same class. JD are you going to tell me that you never bought an ice cream pop from a candy store or corner market? Did you ever have a childhood or were your born a completely heartless machine? Were you raised in a cage with a terrycloth surrogate mother? THESE ARE CALLED CHEST FREEZERS. Google it. Trust me. It is about normal life outside the test tube."
If this is such common knowledge then why are 99% of all fridges still the horizontal loading design? Fridges are one of the largest energy drains in the house. Cutting their power requirements by 1/10 for a similar or lesser price would greatly aid creating a high tech but low energy lifestyle.
"why are 99% of all fridges still the horizontal loading design?"
Because it's much easier to access what's inside. It works well for the grocer, since they just stock the same item in stacks.
First off, for the folks marvelling that JD has never seen a chest freezer, please note that the device in question is *NOT* a freezer, but a refrigerator.
I've personally never seen a chest refrigerator, outside of a commercial setting, although I've owned chest freezers.
Second, John Markos O'Neill is on to something there with his notion of a way of capturing the "coolth". ;-)
Here are a few possibilities:
1: A standard upright fridge with multiple doors...one for each shelf, and each shelf self-contained except for a conduit to the chiller which would be on the top...meaning you would only lose a single shelf's worth of "coolth" (I love that word) when you open it.
2: Have the shelf doors hinged on the bottom, and with "glides" on the sides, so you lose only a fraction of the "Coolth" you would with a traditional side-hinge.
3: Better yet, but more complex. Each shelf is actually an individually removable drawer. You remove an entire drawer/shelf at a time, and that drawer/shelf opens on the top, like the chest freezer. Connection to the chiller conduit would be a coupling at the back of the shelf which closes when the drawer is removed and opens when the drawer is opened.
4: God's Refrigerator, mark 2. When I grew up (in the 70s, in the Northeastern US), it was as cold as a refrigerator outside for much of the year. Mum would always put leftovers (and the woman cooked as though she was feeding an army) outside on the porch until the dish cooled down to the ambient outdoor temperature before putting it in the real fridge. This, of course, saved the fridge the work of cooling the dish, and left it with only the job of maintaining the temperature.
Okay, now I'm not necessarily recommending everyone put their food outdoors in cooler months, but rather am considering a heat-pump sort of thing which could use heat from the fridge to heat the house during the winter, but deposits it outdoors in the summer, and uses "coolth" from outdoors to supplement the action of the fridge when it's cold.
Sidenote: With the individually sealed drawer/doors I recommended, nobody bigger than a small infant is going to get trapped in the fridge, and hopefully anyone small enough to get trapped would also be unable to open the doors.
People have already pointed out the problems with this idea, the fact that it's hard to get at your food, the fact that it takes up more floor space (especially since most of us have cubby holes that fit our fridge pretty exactly) and the fact that you need a seperate freezer.
However, it just goes to show that you can still have cold food, even if energy prices go thru the roof.
When you're taking out that patent, Roland, here's another feature for you.
Make sure that the lids slide off, rather than operate on a hinge. Opening a hinged top will suck some of the "coolth" out, following in the wake of the door. Pulling a sliding top off, on the other hand, will have much less wake.
It also provides a good way to make sure the drawer is fully closed. I've had a chest freezer accidentally propped about a cm open, and it not only wasted energy, but frosted the heck out of the inside of my freezer. :-(
The energy comparison is misleading. It does not take into consideration that this chest frige is much smaller than a regular refrigerator, as well as the fact that regular refrigerator also has a freezer, which is much more energy intensive because you need to maintain a much larger temperature difference between the freezer temperature and room temperature, than the chest frrige does, which is between the 5C interior temperature, and 18C room temperature, as claimed by the paper.
With all other conditions equal. The energy consumption is roughly proportional to the square of the temperature difference. The amount of energy require to transport one calorie of heat from a cold source to a hot source is roughly proportional to the temperature difference, for one thing. The heat leak, hence the number of calories needed to be transfered per unit time, is proportional to the temperature gradiant, too. Combine the two you get the square proportionality relationship.
Therefore, to maintain a freezer of comparable size to -10C from the 18C room temperature, compare with a frige at 5C from the 18C. The energy cost is the square of (28/13), 4.64 times bigger. And the frige in the picture is less than one half the refrigerator at my home, so that's another 2 times factor. Combined, his chest frige really is not that much more energy efficient after all.
The claim of the factor of leaking cold air has been greatly exagerated. Let's do some calculation. Each time you open a regular refrigerator, let's say half of the cold air (which is an exageration) is replaced with room temperature air. That's 12 cubic feet going from 5C to 18C. 12 cubic feet air is about 0.34 cubic meter, at 1.29 kg per cubic meter that's 0.438 kg. Specific heat is about 0.4 cal/(gram*degree) so that's 2280 calories lost.
The refrigerator operates between 5C and 18C, which is 278K and 291K. Assuming a 100% efficient heat pump, it costs 13 calories of net energy to transport 278 calories from the cold source to the hot source. So it costs 107 Calories of net energy to make up the loss of 2280 calories lost due to each door opening.
107 calories times 4.1855 cal per joules, gives you 448 Joules, which is 1.244x10^-4 kw*hour. That's a totally insignificant energy cost comparing with the 1 kwh per day consumption. Even if you open the refrigerator 20 times a day, and the peak pump is only 25% efficient instead of 100%, you are still talking about 80 times more energy, which is still just 1% of the 1 kwh per day energy cost, still very insignificant.
So lying the frige down instead of sitting up, really doesn't make much difference after all. So other factors are much more important.
Quantoken
I can't see quantoken's post, I'm sure it's some well thought out reason why we can't use these, probably along the lines of how inconvenient they are etc.
As I've said before, first said by JD, frivilous lifestyle bullshit.
- We do not need to drive 1 person around in a vehicle that gets 10mpg
- We do not need to use vertical fridges
- We do not need to heat every room in the house, and the ones we do heat don't need to be 75 degrees
- Standard light bulbs are still in the vast majority of houses, these are flagrant wastes of power compared to CFs
- Nuclear reactors in the US use way too much uranium, they don't have to use nearly that much.
Roland:
I am not disputing the 1/10 power figure. I am saying it's merely due to the fact that it is just a frige without a freezer, compare with the regular refrigerators that come with a freezer, and also it is way much smaller than a regular refrigerator, meaning less food can be stored.
It of course uses less electricity and it is also 10 times less useful as a refrigerator. The energy saving has nothing to do with whether it lies down or stands up, and has everything to do with cutting the capacity and usefulness.
There is nothing I like better than when an interesting idea gets posted on this blog and all the commenters jump all over the drawbacks to show how it can't help. A kid might crawl in it and die. It's smaller. It's just a fridge without a freezer. Jeez!!! The point of the post is that there is so much room for increased energy efficiency that we haven't even really started to think seriously about it yet. The "chest fridge" is an idea in embryo, nothing more. Quit being such whiners.
How is it less useful than a standard fridge?
I used to own a chest freezer and a vertical freezer at the same time, and to me, one was just as easy as the other.
Yes, in the chest freezer, you had to shift stuff around to get to the stuff on the bottom, wheras in the vertical one you had to shift stuff around to get to the stuff in the back.
Help me out here, I'm not seeing the huge difference in usefulness...
Look at the photo I insist that it is much smaller than a regular home refrigerator. The author claims that it is converted from a regular chest freezer. It looks like the kind of chest freezer slightly lower than the kind I see near the wal-mart checkout that contains kids icecreams. If that's the case then the volume is only 1/4 of a regular home refrigerator.
Saving energy on saving size and capacity is really no improvement of efficiency. If that is then I propose you just don't eat any food that needs to be preserved in a refrigerator, and get rid of it altogether. If you return to the caves, eat raw meat and forfeit all modern lifestyles, then you could practically cut energy use to zero. Is that what you want?
Roland said "But since it's so cheap and so efficient you could just have two of them."
this has got to be the classic expression of Jevon's paradox unwittingly expressed by an PeakOilDebunked Anti-Doomer Gladiator. As I have said on many occasions,"holy shit! are we ever fucked!"
I was just about to write a similar post to Quantoken's first post. He's exactly right. All things being equal the orientation of a fridge makes virtually no difference to its energy use.
Rather than guess at the size of the freezer, I looked it up. It's a Vestfrost 255.
According to the manufacturer's webpage, its capacity is somewhere in the mid-range of their upright fridg's capacities. Since, however, their measure of capacity doesn't include a unit of measure, let's take it's dimensions and compare them to the 'fridge in my regular old suburban dwelling.
This Vestfrost is 85cm x 126cm x 60cm, for 642,600 cm^3.
The fridge side of my upright Kenmore fridge/freezer, which adequately supports a family of 4, and came pre-intalled by the builder (not some special energy-conscious model...just standard suburbia fare) is 64cm deep x 148cm high x 45cm wide for a total of 426,240^3.
So you're right...the comparison isn't valid... the chest fridge seems to have 150% MORE volume than mine!!!
As Darth Vader would say, "Im-pressive. Most, Im-pressive."
AlbertusMagnus:
Again your comparison is invalid. You obviously have a small refrigerator if it is only 148 cm high. Mine is 69.75 inch high, 35.75 inch wide and 33.6875 inch wide. Which is 177cm x 91cm x 86cm, 1.385x10^6 cm^3. My refrigerator is pretty standard. It's the same height of all the dual door (left and right)refrigerators you see in stores.
Quantoken:
Are you measuring inside or outside? Also, are you measuring both sides or only one? If you have a side-by-side with one half over 30 inches wide, the total combined would be about 5 feet, wouldn't it?
I've never seen a fridge/freezer that width, nor a cubby to fit it.
Are we discussing apples and apples?
...just to clarify, Quantoken, I'm measuring the *inside* of the 'fridge, not the outside. I'm measuring the volume of the area which actually needs to be refrigerated.
Is that what you're measuring? Here in the 'States, we generally measure volume of such things in cubic feet capacity. I realize this may be different in other parts of the world, and don't know where you hail from.
Okay, I'll admit a moment of brainfade here. I have no guarantee that the measurements of the Vestfrost were interior either.
A bit more research says the Vestfrost freezer has about a 22 cubic foot capacity. The buying guide over at Sears.com recommends 4-6 cubic feet of capacity per person.
Compare this with standard refrigerators on the Kenmore website...where you'll find 21-28 or so cubic feet for side by sides. I don't know if that measures both sides or not, but a freezerless freezer over there is 16.7 cubic feet, so I'm guessing the 21-28 is both sides combined.
If so, the Vestfrost is still significantly roomier than a normal fridge. If not, perhaps my fridge and the Vestfrost are on the slightly small end of that 21-28 cubic foot range, but certainly not enough to account for that sort of overall energy savings. In any case, it's still over 5 cubic feet more than at least one standard sized fridge you can buy in an American department store.
In any case, I stand by the fact that my fridge is adequate to cool sufficient food for a family of four, one of whom is a teenager and therefore ought to count as at least two people. ;-)
BTW, while poking around to find this, I've found chest refrigerators already available commercially. There's everything from large ones for food service to small chest freezers at backwoodssolar.com with $75 conversion kits to turn them into refrigerators.
D'OH!
Okay, one further correction. Looks like the truth is somewhere between the two.
The Vestfrost SE255 has a capacity of 239 liters, which is a little over 8 cubic feet. I misread the 22 cubic foot reference...it was comparing the energy requirements of the Vestfrost to a 22 cu ft. fridge. My bad.
Okay, at 8 cubic feet, it has about half the capacity of a standard fridge...and 1/10 the energy costs. To double the capacity, you'd need to add roughly one quarter of the existing height, width, and depth, or double one dimension, or otherwise tweak the dimensions.
I'm still impressed...not quite *as* impressed...but a five-fold improvement in energy efficiency is still far from a bad thing.
Now that your numbers make sense. 239 litre is 8.44 cubic feet, that's way much smaller than a stand up dual door 25 cubic feet refrigerator, which is pretty much the standard equipment of an American single family home.
But the bigger factor is you are cutting off the freezer and use it as a frige only. It makes a big difference what kind of temperature difference (between room temp and the interior) you try to maintain. Since theoretically the power consumption is roughly proportional to the SQUARE of the temperature difference. The author maintained only a 13 degree difference in his frige (5C versus 18C). A typical freezer would maintain 33 degree difference (-15C to 18C), which consumes (33/13)^2 = 6.44 times more power. Combine that with the almost 3 times volume (25/8.44). That's a 19 times difference in cooling capacity!!! So if you save only 10 times electricity, not only it is not impressive at all, it is actually running at lower efficiency after all.
Like I said, cutting capacity to save electricity is not an improvement of efficiency at all.
Roland:
You don't get it. You lose a major chunck of the food preserving capacity by not having the freezer in this chest frige. And you settle for a much smaller volume. It is not a saving by efficiency. It is a saving by cutting corners. You might as well just eat food that does not need preservation, and go without a refrigerator that way.
At the end of day it does not save you any thing. You save 330 kwh electricity per year by having this smaller frige without a freezer, which is about $33 saving if each kwh is 10 cents.
But because your frige is 3 times smaller, and do not preserve food very well (by not having the freezer). You need to make more frequent trips to grocery stores to get fresh food. If you take one extra trip per week, and each trip is 6 miles one way, that's 624 extra miles traveled per year, at 24 miles per gallon, you are consuming 26 gallons extra gasoline, at $2.5 per gallon that's $65. Just to save $33 in electricity. That's not only a waste of money but also a waste of energy!!!
Instead I would encourage bigger refrigerators that come with a freezer, so that you can take less number of trips to grocery stores.
It's common knowledge that the most energy efficient way to keep any fridge is "full," so having the right size fridge for what your family actually uses would seem to be key.
Most important, though, is the gent in question has a 10 fold energy savings vs a 22 cu ft. fridge. Even if you have to run three of them, you still save.
Now mind, this is something some guy did at home. Put some real engineers on it, and I wonder what their savings would be...but that's speculation.
I personally see no reason why chest refrigeration wouldn't scale, since we see supermarkets use it all the time...BUT...supposing it can't, there's still a simple solution to your capacity issue. If you really have a family of 5 or 6 and need 25 cu ft., you get multiple chest fridges.
Roland said...
Quantoken, if vertical fridges are so efficient, why do they have to operate 100% of the time? This one operates one to two minutes every hour, apparently.
Haven't we already covered this... the orientation of a fridge doesn't make a meaningful difference to the energy use! It might if the door was left open all day but that isn't what we're talking about is it.
Haven't we already covered this... the orientation of a fridge doesn't make a meaningful difference to the energy use!
Isn't that your conclusion, as opposed to a bit of evidence? I believe the meter the man hooked up to the machine rather proves that it does make a difference, doesn't it?
Roland said:
"Yup, here's the thing - if orientation makes no difference to power use, then this fridge, having a third the volume, should use a third the electricity. But it doesn't, it uses one-tenth the electricity. Is a normal fridge ten times larger? Yes, I know Quantoken, vertical fridges use more energy, but does this really account for the whole difference? Here's a quote from the fridge's inventor:"
Roland: How many time do I need to repeat this: A bigger factor even than the volume is that a regular refrigerator has a freezer, while this chest frige does NOT has one. That factor plus the volume difference accounted for all of the 1/10 power consumption. Whether it's layed down or stand up has virtually no effect.
There is a huge difference between a freezer, which maintains a much larger temperature difference, and a frige, which maintains a much smaller temperature difference. Of course, if you maintain a zero temperature difference, you save 100% of the energy.
Not all refrigerators have a freezer. In the home where I grew up, we had fullsized refrigerators and fullsized freezers. They were separate appliances. You can still get them. Check out sears.com.
The author of that article showed a complete lack of basic physics knowledge.
He suggested that when the temperature difference doubles, the energy consumption is only slightly more than double. The fact is the amount of heat needed to pump from the cool interior to warmer outside is doubled, so is the amount of energy required to pump each calorie of heat across the temperature difference. So the energy consumption should actually be quadrippled, not doubled.
He also suggested that solar panels work more efficiently during hot days versis cold days. The fact is consider thermal dynamics, hot weather actually REDUCES the efficiency of solar panels, not increasing it. That's proven both by actual numbers and by established physics theories. You may have less days of good sunshine. But when you do have clear sky and your solar panel is aligned properly, you get more power on winter days.
It is true that you lose more cold air when opening a stand up refrigerator. But any reasonable calculation shows this is a totally insignificant loss compare to typical operational energy cost, unless you are opening the frige every 5 or 10 seconds during the day, which none of us do. You just got to remember the air is very dilute. And that constant heat leak through the material of the refrigerator is much larger than instantaneous heat loss through opening doors.
To make my point, please have a look at this commercial product.
Especially look at the R4 model, which is a refrigerator only. It consumes 0.1 kwh, same as the so called chest frige the author invented. But the volume is 23 cubic feet, almost three times bigger. And Yes the R4 is a stand up model, not a chest model!!!
My fault. The interior dimention of the R4 is actually 3.91 cubic feet, not 23, which is the shipping dimention.
But then in the article of the chest frige. The author gives the room temperature as 15 to 21 C, averaging 18C, and the interior temperature is between 4C to 7C, averaging 5.5C. So that's merely a 12.5C temperature difference.
The commercial product I cited is rated at 21C and 32C. Let's take the 32C figure for a comparison. If the interior temperature is 3C, that is a 29C temperature difference, at 0.14 kwh, which is 1.4 times of the check frige.
(29C/12.5C)^2 = 5.38 times
(3.91 cf)/(8 cf) = 0.49 times
The commercial product has total cooling capacity of 2.64 times of the chest frige, at 1.4 times energy consumption. So it's more efficient.
Yeah, I'm not sure I buy it either. A real apples-to-apples comparison would take his refrigerator and stand it up sideways, and compare the energy usage. Or take a standard fridge and tip it over, and see how it runs.
To put it differently, my refrigerator (Sears Kenmore, 2001), runs frequently even when the door has been closed all day. With the door always closed, and no air flowing out, why should it matter what the orientation is?
Nice blog, by the way.
Quantoken,
Perhaps your calculations can explain away these specs:
18-20cf (freezer 1.7cf bigger) freezer 100 kWh more
Chest freezer (19.7cf) stated energy consumption: 435kWh per year
http://www.sears.ca/gp/product/B000QZXQLY/sr=1-2/qid=1181565431/ref=sr_1_2/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363801
Upright “all refrigerator” (18cf) stated energy consumption 335 kWh per year
http://www.sears.ca/gp/product/B000F9EXH2/sr=1-9/qid=1181565671/ref=sr_1_9/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363631
15-18cf (freezer 0.5cf bigger) freezer 78kWh less
Chest freezer (16.5cf) stated energy consumption: 360kWh per year
http://www.sears.ca/gp/product/B000P4YAQ6/sr=1-4/qid=1181565431/ref=sr_1_4/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363801
Upright “all refrigerator” (16cf) 438kWh
http://www.sears.ca/gp/product/B000M0YZGS/sr=1-1/qid=1181565572/ref=sr_1_1/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363631
10-15cf (freezer 1.8cf bigger) freezer 17 kWh more
Chest freezer (12.8cf) stated energy consumption: 362kWh per year
http://www.sears.ca/gp/product/B000P523K0/sr=1-8/qid=1181565431/ref=sr_1_8/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363801
Upright “all refrigerator” (11cf) 345kWh
http://www.sears.ca/gp/product/B000F9CWL6/sr=1-0/qid=1181565591/ref=sr_1_0/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363631
6-10cf (freezer 1.2cf bigger) freezer 66 kWh less
Chest freezer (7.2cf) stated energy consumption: 279kWh per year
http://www.sears.ca/gp/product/B000F8UGZ6/sr=1-7/qid=1181565297/ref=sr_1_7/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363801
Upright “all refrigerator” (6cf) 345kWh
http://www.sears.ca/gp/product/B000HBCADM/sr=1-8/qid=1181565516/ref=sr_1_8/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363631
3-6cf (freezer 1 cf bigger) freezer 98kWh less
Chest freezer (5cf) stated energy consumption: 242kWh per year
http://www.sears.ca/gp/product/B000P51XEC/sr=1-9/qid=1181565297/ref=sr_1_9/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363801
Upright “all refrigerator” (4cf) 340kWh
http://www.sears.ca/gp/product/B000L10X32/sr=1-10/qid=1181565516/ref=sr_1_10/104-7294799-5644720?ie=UTF8&searsBrand=core&mqnodeid=16363631
If design (horizontal doors vs vertical) makes such little difference and the delta of degree difference of inside and outside air does, why do many similar sized chest freezers meet or exceed their refrigerator only equivalents?
You keep mentioning that the upright refrigerator used in the original experiment was only more energy intensive because of size and that it also had a freezer attached. I say you are half right, the loss of cold air from the freezer probably does account for a lot.
The usability and convenience arguments are purely subjective and if you are in a position (building new or remodeling) to plan around such considerations you can have high function and usability. It make take more floor space but a chest fridge allows more upper cabinets to be installed and can be used as a temporary work surface. Rack and baskets systems can be made or purchased to make the food access issues minor.
The fact is you haven’t sufficiently refuted this idea, real world evidence is much more compelling than theoretical calculations.
My links didn't work, but you can browse the actual models at sears.ca...
Quantoken is missing the 2 important points:
1. Opening the fridge doesn't account for much "cold" loss -- he is right.
But he misses the fact that door of the fridge (esp. seals/gaskets!) is usually the weakest point of isolation. It's more efficient to keep the weakest point of isolation on top of the fridge.
2. Also, freezer (by design) usually have much thicker isolation (after all, it's designed to keep much colder temperatures), and using it merely as fridge, we take leverage of the better isolation than usual fridges-by-design have.
Hello Everyone
I have read the above discussion.
We followed Mr Chalko's lead in 2007 and have had the mentioned chest freezer at our property in NSW, Australia, not far from Queensland border, for the last 18 months using the temperature monitor he desribes, we bought it from him. The freezer, run as a fridge uses about 200 Watts/day. This is roughly the same as the standby usage per day of our inverter!!
It has several cages hanging from the lid when you open it, where you can store vegies or whatever, and is very roomy.
As Tom says there's ample room for a case of plums (my addition or beer !)
Tom deserves Nobel prize or similar.
Yes, it's not a convenient as normal fridge etc etc, but 200 watts/day !! When we think how inefficiently designed most fridges and freezers are, and we are burning millions of tonnes of coal daily, to cool the atmosphere as the cold air frequently leaves the repeatedly opened fridges & freezers.)
Run as a freezer it is supposed to use about 600-700 Watts per day, which is still very little.
The secret is, top opening whereby warmer air leaves, not cold air, and lots of insulation, the walls are very thick. Good luck to all.
BB
Finally some clarity, and from a user of the machine in question! Thanks BB!
One of Quantoken's earliest posts contained the key, but it was never pursued. He referenced the Sunfrost website and its table of refrigerator/freezer performance. The table shows a series of machines of various sizes that are set up as either freezers or refrigerators using different thermostats so it is possible to compare identical machines operating in both modes. The freezer versions use approximately 3 times the power used by the refrigerator versions All of the Sunfrost machines use s bit less power than average machines since they are more heavily insulated and use very efficient compressors.
As for vertical vs. horizontal, it is not so much the losses during opening and closing, its the losses through the seals when the door is closed. A leaky vertical seal is far more wasteful than a leaky horizontal seal.
Nicus
To anyone who has read through this debate regarding vertical and horizontal designs:
The horizontal design is more efficient. The main reason, which has been overlooked in this discussion, is the fact that the seals on the doors of these devices are incredibly less efficient at insulating.
Therefor, in a vertical design, the door will constantly leak cool air while allowing warmer outside air to infiltrate. A horizontal design avoids this problem by locating the weakest link, the seal, to the top of the appliance where it has the least negative impact.
Additionally, as to the argument that there is less space available, this is an apples to oranges comparison. In a horizontal design, more of the space can be utilized with proper planning. Using simple crate style baskets, the contents of the fridge can be organized rather effectively.
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