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a lot of works. I can't see the need. With the thermostat in the refrigera tor and the evaporator around the freezer, the unit will run until the refr igerator is cold and by then the freezer will be adequately cold. That can be adjusted by adjusting the air flow between the two. I can't see adding a second compressor to take the place of an air damper.

o

he

. Someone mentioned a unit with multiple freezer compartments. It would be a very specialized use to need multiple freezer compartments in a single re frigerator. None of that makes any sense to me.

Yes, an adjustable leak, although I think you are ignoring that the refrige rator compartment is where the thermostat is typically located. The adjust ment process is to set the temperature of the refrigerator and adjust the d amper to control the portion of cooling that reaches the refrigerator compa rtment with the rest remaining to cool the freezer. Adjust the damper to g ive the desired freezer temperature.

The point is unless there is some reason why this won''t work in a particul ar case, the added cost of the multiple thermal zone is unwarranted.

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Rick C. 

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Rick C
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lot of works. I can't see the need. With the thermostat in the refrigerator and the evaporator around the freezer, the unit will run until the refrige rator is cold and by then the freezer will be adequately cold. That can be adjusted by adjusting the air flow between the two. I can't see adding a se cond compressor to take the place of an air damper.

I haven't bought a fridge in over 30 years, so I have no idea what is cheap . The point is how much of that 800 Euros went to paying for the added tec hnology? What did you get for it? I bet you would have to add instrumenta tion to tell the difference. In other words, no observable benefit.

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Rick C. 

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Rick C

ote:

tments when using a single compressor?

oils with valves. It is much more likely to have a controlled damper to mod ulate the amount of cold air from the freezer entering the refrigerator. My refrigerator has a fan, but I can't say for sure where it blows, freezer o nly or freezer and refrigerator.

idge would sometimes freeze things in the bottom when the temperature was s

scale? Or does your refrigerator not keep things at the set temperature?

he inside of the fridge, so talking about that sort of accuracy is delving into fantasy. I would also point out that white is a poor color for emissi vity and will give the worst result. Black gives a more accurate indicatio n of it's own temperature, but the thermometer is calibrated for some value of emissivity and any other value gives additional error.

let you figure that out.

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Rick C

Maybe they just have two evaporator circuits and I've always misunderstood the brochure descriptions as meaning that there are two compressors.

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Grant
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Grant Edwards

If they have a single compressor, it would be sized to match the coils... b ut which one? What happens if one compartment demands cooling while the ot her is already demanding cooling. Are both coils driven? If not, does one compartment continue to warm up while the other compartment is cooled? If both coils are connected to the single compressor at the same time, is the design optimized for working with both coils or just one?

Having two evaporators seems like a poor compromise no matter how you look at it. Two compressors is a lot more expensive, but would work most effici ently and effectively which I thought was the point of using two evaporator coils. I don't see anything wrong with using a single compressor circuit with it cooling both the freezer and fridge.

I've had mine on a power monitor for a day now and it seems to run most of the time at around 170 watts. I noticed overnight it cut off every couple of hours for about a half hour. I've also seen the power spike significant ly, then dip for a half hour or so. I think that's the defrost cycle. It was accidentally turned off for a couple of hours today and the inside temp eratures barely changed. Tomorrow the power monitor (which is actually a p ower timer switch) will cut if off from 6am to 9am. I'll measure the temp at 9am. I don't know if I can download a record of the usage. I should c heck. It keeps detailed info for a day and daily numbers for a month, then monthly data for a year. No, looks like no downloading possible.

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Rick C. 

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Rick C

Well, one case is where you want seperate control in temperature of freeze and cool section. I've looked at a brochure, and in almost all cases the simpler fridges only let you adjust the temperature of the cooling secion. The freeze section is only specified as "3=1 stars" or so.

Mat Nieuwenhoven

Reply to
Mat Nieuwenhoven

You're right of course, the accuracy was unwarranted because of the unknown emissivity. The spec of the thermometer says +/- 1.5 % or

+/- 1.5 % of the measured value (it goes up to 380 C). So in case it displays 4.0 C the accuracy is 0.06 C, and the single decimal is fully warranted. The emissivity is unknown, but I've measured multiple items with different colors on the same item, and it does not seem to vary much. The only significant deviation so far is on our central heating radiators where the thermostat valve is some kind of shiny metal: the radiator itself just behind the valve might read 61C, the valve itself through which the hot water enters the radiator reads 29C, and it is all metal.

Mat Nieuwenhoven

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Mat Nieuwenhoven

I bet boith coils are driven. There is a "super freeze" mode on it which you can use to cool down the freeze section quickly if you filled it completely with unfrozen food; that times out after 65 hours. I've never used it on our current fridge, but on the old one twice or so, and the cooling section stayed on the temperature as set.as

Two compressors are rare. It must be one compressor with two coils. If the freeze section is below the cool section (which is the vast majority) , there cannot be air leak (cold doesn't move upwards) unless there is a ventilator to move the air around.

Seriously, 170 W and running most of the time? That could be 1000 kWh per year. Ours runs shortly every few hours, I have not timed it but it seems to be off most of the time. I'll see if there's a cheap logging power monitor to be had, just to log how often and long it runs. The actual energy use I can measure, but that device is in use for this week.

Mat Nieuwenhoven

Reply to
Mat Nieuwenhoven

ote:

know

ator

for a lot of works. I can't see the need. With the thermostat in the refrig erator and the evaporator around the freezer, the unit will run until the r efrigerator is cold and by then the freezer will be adequately cold. That c an be adjusted by adjusting the air flow between the two. I can't see addin g a second compressor to take the place of an air damper.

te

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n the

ain.. Someone mentioned a unit with multiple freezer compartments. It would be a very specialized use to need multiple freezer compartments in a singl e refrigerator. None of that makes any sense to me.

igerator compartment is where the thermostat is typically located. The adju stment process is to set the temperature of the refrigerator and adjust the damper to control the portion of cooling that reaches the refrigerator com partment with the rest remaining to cool the freezer. Adjust the damper to give the desired freezer temperature.

cular case, the added cost of the multiple thermal zone is unwarranted.

Sorry, I don't know what "3=1 stars" means. A separate set of coils and thermostat is not needed to maintain a different temperature in the freezer . My refrigerator is doing it quite well. The timer cut it off for three

nce can regulate two temperatures at once!

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Rick C. 

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Reply to
Rick C

We have separate machines for fridge and freezer, which allows a lot more choice of format and location. Freezer is in another room, with the fridge under the worktop in the kitchen. If one fails, you don't lose everything. Less efficient I guess, but more convenient. Both are well over ten years old, but don't get obsessed over power consumption...

Chris

Reply to
Chris

e:

partments when using a single compressor?

o coils with valves. It is much more likely to have a controlled damper to modulate the amount of cold air from the freezer entering the refrigerator. My refrigerator has a fan, but I can't say for sure where it blows, freeze r only or freezer and refrigerator.

fridge would sometimes freeze things in the bottom when the temperature wa

ius scale? Or does your refrigerator not keep things at the set temperature ?

the inside of the fridge, so talking about that sort of accuracy is delvin g into fantasy. I would also point out that white is a poor color for emiss ivity and will give the worst result. Black gives a more accurate indicatio n of it's own temperature, but the thermometer is calibrated for some value of emissivity and any other value gives additional error.

You need to learn how to read specs. The first 1.5% applies to the full ra nge I suspect and the total error is the sum of the two or the greater of t he two.

Stop pretending these devices are accurate. Try measuring a dozen differen t locations in the fridge. You will get a dozen different readings with a

acy.

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Rick C. 

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Reply to
Rick C

. but which one? What happens if one compartment demands cooling while the other is already demanding cooling. Are both coils driven? If not, does one compartment continue to warm up while the other compartment is cooled? If both coils are connected to the single compressor at the same time, is the design optimized for working with both coils or just one?

How does that make any sense? If both coils are always driven, that is lik e having only one coil, the ratio of cooling is fixed. In fact, it is wors e because with one coil a damper is used to control how much cooling applie s to each compartment, adjustable by the user. With two coils always drive n there's no way to change the apportioning.

I have no idea what your super freeze mode might be doing if the two compar tments have no air flow between them there is no way for the second coil to help cool the freezer. What are you talking about?

ok at it. Two compressors is a lot more expensive, but would work most effi ciently and effectively which I thought was the point of using two evaporat or coils. I don't see anything wrong with using a single compressor circuit with it cooling both the freezer and fridge.

I don't know why you say the "vast majority" of units put the freezer in th e bottom. Here very few units have the freezer in the bottom... VERY few. They are either freezer in top or side by side with tall skinny doors. A fan is not uncommon. My freezer in top uses a fan to improve heat exchange and it provides adjustable cooling to the lower refrigerator via the dampe r.

of the time at around 170 watts. I noticed overnight it cut off every coupl e of hours for about a half hour. I've also seen the power spike significan tly, then dip for a half hour or so. I think that's the defrost cycle. It w as accidentally turned off for a couple of hours today and the inside tempe ratures barely changed. Tomorrow the power monitor (which is actually a pow er timer switch) will cut if off from 6am to 9am. I'll measure the temp at

9am. I don't know if I can download a record of the usage. I should check. It keeps detailed info for a day and daily numbers for a month, then monthl y data for a year. No, looks like no downloading possible.

Yes, I agree, you have not timed it so you don't know how much it runs. M y fridge is over 30 years old and may be having problems. A few months ago when the weather was warmer it was not keeping cold enough. I've been pay ing closer attention because of this. $156 is what I estimate annually. W hat I've read is the typical unit runs a third of the time. So I could sa ve around $100 a year.

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Rick C

No, it is 1.5% of the reading OR 1.5 C, whatever is greater. Incomplete spec, because they don't say if it is for C or F (I suspect C as it is an european device), Because it can do F and C, therefore in F 1.5% of reading would be more accurate. Below 0 C is it less accurate, 3% or degrees.

Well, higher in the fridge is is somewhat warmer, as specified in the user's manual. Different packages inside the fridge give different readings (by several degrees), likeley due to differences in emissivity.

I have started to measure the fridge's energy consumption today. While running, the fridge takes 55 to 66 W (it really varies) , I wonder if it has a multispeed compressor. Assuming 60 W average, then after some days, I should be able to determine how much % of the time the fridge is on.

Mat Nieuwenhoven

Reply to
Mat Nieuwenhoven

range I suspect and the total error is the sum of the two or the greater of the two.

ent locations in the fridge. You will get a dozen different readings with a

acy.

I put my fridge on a timer to not run when the power is expensive, 3 hrs, t wice a day it is cut off. I measure about 1 or 2 degree rise in temperatu re, but only by looking in small spaces.

Funny thing about emissivity, if you point your thermometer at a shiny box of frozen food or a shiny plastic bag the heat from the outside radiates in ward and is reflected back into your thermometer, raising the reading signi ficantly. So if I just take every temperature I see in the freezer, after sitting with the door closed for three hours, I will find up to 10 degree variations which is pure BS. It's the variation in emissivity and the room warmth reflecting back to the thermometer. The low readings can't be fals e however unless the fridge were actually a heater keeping the food from fr eezing while in an arctic environment.

I turned my thermostat up in the fridge and also adjusted the flap away fro m the coldest setting. I think the flap was virtually closed cutting off e ffective cooling from the fridge and causing the motor to run constantly. I can see it now cycles and can even see the defrost cycle where it runs t he heater and leaves the compressor off for a while.

The power variation is from temperature differences. If the returning gas is warmer it takes more work to compress it. That reminds me, I need to cl ean the coils.

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Rick C. 

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Rick C

Well, I've measured the fridge's energy use for 25 days. Extrapolated to a year it used 118 kWh, let's say 130 because in summer our kitchen is warmer. It ran 38% of the time. If I take freezer and cooler volume together (330 liter), then it comes out to 0.39 kWh per liter per year.

Mat Nieuwenhoven

Reply to
Mat Nieuwenhoven

Times 11 cents a kWh in Texas that?s about 14 dollars a year if I have done the math right. Never going to be cost effective to replace.

Can I assume no kids at home as that could multiply the result by four.

Reply to
Brett

That would be a tiny refrigerator, here (USA). Ours is ~600L and it's just "modest" in size (two people).

It's old so not terribly efficient -- ~800KWHr/yr.

OTOH, it doesn't cost us much to run (~$8/month) -- any one of my servers or workstations (+ monitors) easily consumes more on an annual basis (as they have considerably higher operating duty cycles).

And, of course, with a 9-10 month cooling season, money spent to cool FOOD is negligible compared to what it costs to keep PEOPLE cool!

Reply to
Don Y

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This is a very small refrigerator, approx 11 cu ft. But even so, this ener gy usage is very, very low, about 13.5 watts. When you open the door and t he light bulb comes on the energy use quadruples. I believe he already sai d his unit has no defrost cycle, so that alone makes it very different from 99.9% of the units sold in the US.

Even so, I find the numbers to be surprising.

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Rick C. 

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Rick C

Indeed no kids at home normally. But the result doesn't get much higher even then. I saw a minor increase over the festive season when it was used much more.The cooler door bleeps if is it is open for longer than a short time (a minute or so).

You mean on average over the year if it were running continuously? White- good equipment like a fridge or washing machine in the EU must be specified in kWh/year based on a prescribed use pattern. Our model is specified for 167 kWh/year. It was not even the most efficient in the catalog, there were other considerations too. It is this model without the no-frost:

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cnp-4813_89392.html

I guess for most households here this is upper middle class fridge/cooler with vertically stacked cool/freeze section. About 60 cm wide which is a standard here for kitchen cabinets. You can buy side-by-side freeze/ coolers, but they are much less efficient and not many people have the space for it. Those who want a large freezer frequently have a box-type (lid on top) freezer in the cellar of garden shed. Our kitchen is

250x250cm exactly, and I guess that is about normal for standard houses. But you don't really need much storage because the supermarkets are usually close (walking or bicycling distance). I guess if you buy things once a week for the whole week you'd need more. But if we have a three- course meal for 9 persons, indeed space is tight.
3.6 W according to my power meter. The light is a bright LED at the top front shining downwards, which illuminates the cooling section very well. But even on older fridges we had the bulb was only 5W or so.

alone makes it > very different from 99.9% of the units sold in the US.

The cooling section doesn't need one, because it's minimum temperature is

  • 1 centigrade, and like I wrote before, there is no air connection between freezing and cooling sections. We could get almost the same model with no-frost in the freezer section, but it used like 50% more energy, and that's not worth it for us. There's not much ice accumulating there anyway.

Energy efficiency is very important here. Most people would pay 23 eurocent/kWh . In test of consumer organizations energy use is a major point for any product. Cheaper models are usually worse on energy use per liter. I don't think there are double-door models that rely on airflow from freezing to cooling section.

Mat Nieuwenhoven

Reply to
Mat Nieuwenhoven

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