Increasing fridge efficiency with PCMs - Page 3

Piwoslaw · 02-01-13, 05:10 AM

^^ Only water doesn't always freeze at the temperature that you need energy storage.

AC_Hacker · 02-01-13, 10:54 AM

I think that for the price of the thermal balls, you could buy a small chest type freezer and a thermostat that would work in home refrigerator range and then you'd see some awesome energy savings.

Reason being the insulation and compressor are more efficient, and you don't spill air every time you open the door.

The only application I know of where PCMs are used effectively is in cruising boats that will be traveling in tropical waters. The power of the engine is used to drive the compressor, and eutectic salts are used as the PCM... I think they call them 'brine plates'. Their effect is to give longer periods of refrigeration between motor runs. But they're used as a storage medium, not as an efficiency enhancer.

I think that the appliance itself should be suspect. The manufacturers chief concern is to build a refrigerator as cheaply as possible and sell it. There is no direct link between what they do and the efficiency experienced by the owner of the refrigerator. Of course, if the efficiency is absolutely awful, people will stop buying the product, but otherwise it's not their concerns. Manufacturing cost is a much bigger concern.

That's where government intervention come in, to mandate that the manufacturers must make more efficient models. And then they do... that is what the Energy Star thing is all about.

There are companies that do make very high quality, very high efficiency refrigerators for specialty markets... like off-grid solar people.

The company that comes to mind is Sun Frost. They make very high quality, very efficient refrigerators, and they are expensive. Their refrigerators also use a large cooling plate in the refrigerator section of the unit (not the freezer) and it is designed to operate above freezing, so there is no frost issue, and produce lasts much longer, because the moisture in the refrigeration compartment is not being frozen out of the air.

Also, the heat generating part of a refrigerator, the compressor & condenser, is put on top of the refrigerator, not in the bottom or back or (cringe) built into the sides of the refrigerator, so the heat of operation does not need to be re-removed every cycle.

(* Sunfrost also has a very interesting page of other sustainable offerings *)

Our mass market refrigerators are crippled appliances. Their design is dictated by the economics of manufacturing.

If a significant number of people started building their own high efficiency refrigerators, they would be happier as people (less money lost, more in the pocket) and this would turn the industry.

Best,

-AC

ecomodded · 02-10-13, 07:40 PM

Quote:

Originally Posted by ecomodded

I am curious if my 10 gallons of water jugs is non functioning as the previous posters surmise.
So for the sake of science i am going to baseline my fridge yet again, then remove the array of water jugs and measure again.
This will be accurate, it will be measured using my kill-a-watt meter and i will open the fridge door a equal amount of times on each of the days to maintain continuity.
I had planned to do this long ago, but was happy or pleased with the water jugs so neglected or elected not to pull them out.

I feel the frozen water jugs in the freezer section aids the refrigerator as well,it appeals to my common sense.

I retested and found that Their was no measurable gain or loss to the addition of the 10 gallons of water jugs. The tests were done twice and same results were found, $23.33 yearly usage costs. Which i found odd but proved to be true.

AC_Hacker · 02-10-13, 08:42 PM

Quote:

Originally Posted by ecomodded

I retested and found that Their was no measurable gain or loss to the addition of the 10 gallons of water jugs. The tests were done twice and same results were found, $23.33 yearly usage costs. Which i found odd but proved to be true.

Well ecomodded, I congratulate you (quite seriously) on your scientific work.

It's easy to fall in love with your hypothesis, and quite tempting to ignore results that don't support your hypothesis or worse yet, to not report at all that your experiment did not support your hypothesis.

While this may leave you without a proven hypothesis, it does leave you with your integrity.

Here is an essay by Richard Feynman given at the commencement of the 1974 Caltech graduating class. LINK TO ESSAY

Best,

-AC_Hacker

ecomodded · 02-10-13, 10:55 PM

Thanks for the kind words AC.

I enjoyed the Link/ Essay.
Sad to think some of the talented people who wright scientific essays and papers are using a baseline prepared by someone else. Cutting corners is not conclusive to finding the truth. I repeated my test, I wanted the truth not chance. As we all know it has to be repeatable or something is amiss in the study.

My firsts test was flawed, that was my error, i am happy to catch the error,though. It is very important that science prevail and emotions leave the test,completely.
I do not want to steer people in the wrong direction. I want to,if possible help them conserve, in this instance.

So i can say with great confidence adding water jugs has No benefit when it comes to electrical consumption, and no loss once the water jugs are up to temperature. But getting the jugs down to fridge temperature cost loads of electrical consumption, the fridge literally ran for hours to chill the water.

Regards Doug / ecomodded

MN Renovator · 02-11-13, 02:12 AM

I'm surprised that it could possible have been such a similar result. I find a HUGE difference in energy usage between even 10 degrees ambient difference in the house. In the summer the fridge is an energy hog, in the winter it barely runs. The compressor also pulls proportionately more energy when ambient is hot and far less when it is cold, efficiency differences overall are very different. Not sure how it's possible to pull it to the same cent, even opening the fridge a few times would cause significant additional runtime.

Blue Bomber Man · 02-11-13, 08:08 AM

Didn't see this mentioned...

I think the only gain to be had by putting jugs in a fridge is that it displaces air that can "fall" out when the door is opened and is replaced by warmer air.

That being said, one might as well use empty jugs since you may want to remove them to increase storage space at times and would not want to remove all of that cold mass.

ecomodded · 02-11-13, 03:59 PM

I found it hard to believe too, that the energy usage was exactly the same as well,
I retested,Same results each time. I have an explanation, that is directly related to the cold air dropping out of the fridge when the door is opened.

I installed a cold air curtain, a section of blue wood flooring underlay/vapor barrier in the fridge ( see ecomodded fridge thread for the photo) that keeps the cold air from dropping out of the fridge during door openings. All 4 tests were done with it in place, for continuity.
My fridge curtain works excellent.

All test were done under exactly the same circumstances, the water provided absolutely no usage benefit nor usage increase, barring the long run time to initially chill the water jugs.

I challenge anyone who doubts my findings or thinks i made a error to do your own tests, if you can be objective.
I used the cold air curtain in all of the tests, You should as well if you want to replicate my tests.
regards Doug / ecomodded.

02-01-13, 05:10 AM	#21
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	^^ Only water doesn't always freeze at the temperature that you need energy storage. __________________ Ecorenovation - the bottomless piggy bank that tries to tame the energy hog.

02-01-13, 10:54 AM	#22
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	thermal balls I think that for the price of the thermal balls, you could buy a small chest type freezer and a thermostat that would work in home refrigerator range and then you'd see some awesome energy savings. Reason being the insulation and compressor are more efficient, and you don't spill air every time you open the door. The only application I know of where PCMs are used effectively is in cruising boats that will be traveling in tropical waters. The power of the engine is used to drive the compressor, and eutectic salts are used as the PCM... I think they call them 'brine plates'. Their effect is to give longer periods of refrigeration between motor runs. But they're used as a storage medium, not as an efficiency enhancer. I think that the appliance itself should be suspect. The manufacturers chief concern is to build a refrigerator as cheaply as possible and sell it. There is no direct link between what they do and the efficiency experienced by the owner of the refrigerator. Of course, if the efficiency is absolutely awful, people will stop buying the product, but otherwise it's not their concerns. Manufacturing cost is a much bigger concern. That's where government intervention come in, to mandate that the manufacturers must make more efficient models. And then they do... that is what the Energy Star thing is all about. There are companies that do make very high quality, very high efficiency refrigerators for specialty markets... like off-grid solar people. The company that comes to mind is Sun Frost. They make very high quality, very efficient refrigerators, and they are expensive. Their refrigerators also use a large cooling plate in the refrigerator section of the unit (not the freezer) and it is designed to operate above freezing, so there is no frost issue, and produce lasts much longer, because the moisture in the refrigeration compartment is not being frozen out of the air. Also, the heat generating part of a refrigerator, the compressor & condenser, is put on top of the refrigerator, not in the bottom or back or (cringe) built into the sides of the refrigerator, so the heat of operation does not need to be re-removed every cycle. (* Sunfrost also has a very interesting page of other sustainable offerings ) Our mass market refrigerators are crippled appliances. Their design is dictated by the economics of manufacturing. If a significant number of people started building their own high efficiency refrigerators, they would be happier as people (less money lost, more in the pocket) and this would turn the industry. Best, -AC __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker... Last edited by AC_Hacker; 02-01-13 at 10:58 AM..*

02-11-13, 03:59 PM	#28
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	I found it hard to believe too, that the energy usage was exactly the same as well, I retested,Same results each time. I have an explanation, that is directly related to the cold air dropping out of the fridge when the door is opened. I installed a cold air curtain, a section of blue wood flooring underlay/vapor barrier in the fridge ( see ecomodded fridge thread for the photo) that keeps the cold air from dropping out of the fridge during door openings. All 4 tests were done with it in place, for continuity. My fridge curtain works excellent. All test were done under exactly the same circumstances, the water provided absolutely no usage benefit nor usage increase, barring the long run time to initially chill the water jugs. I challenge anyone who doubts my findings or thinks i made a error to do your own tests, if you can be objective. I used the cold air curtain in all of the tests, You should as well if you want to replicate my tests. regards Doug / ecomodded. Last edited by ecomodded; 02-11-13 at 05:01 PM..

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02-10-13, 10:55 PM	#25
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	Thanks for the kind words AC. I enjoyed the Link/ Essay. Sad to think some of the talented people who wright scientific essays and papers are using a baseline prepared by someone else. Cutting corners is not conclusive to finding the truth. I repeated my test, I wanted the truth not chance. As we all know it has to be repeatable or something is amiss in the study. My firsts test was flawed, that was my error, i am happy to catch the error,though. It is very important that science prevail and emotions leave the test,completely. I do not want to steer people in the wrong direction. I want to,if possible help them conserve, in this instance. So i can say with great confidence adding water jugs has No benefit when it comes to electrical consumption, and no loss once the water jugs are up to temperature. But getting the jugs down to fridge temperature cost loads of electrical consumption, the fridge literally ran for hours to chill the water. Regards Doug / ecomodded

02-11-13, 02:12 AM	#26
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	I'm surprised that it could possible have been such a similar result. I find a HUGE difference in energy usage between even 10 degrees ambient difference in the house. In the summer the fridge is an energy hog, in the winter it barely runs. The compressor also pulls proportionately more energy when ambient is hot and far less when it is cold, efficiency differences overall are very different. Not sure how it's possible to pull it to the same cent, even opening the fridge a few times would cause significant additional runtime.

02-11-13, 08:08 AM	#27
Blue Bomber Man Lurking Renovator Join Date: Jun 2009 Posts: 24 Thanks: 3 Thanked 5 Times in 5 Posts	Didn't see this mentioned... I think the only gain to be had by putting jugs in a fridge is that it displaces air that can "fall" out when the door is opened and is replaced by warmer air. That being said, one might as well use empty jugs since you may want to remove them to increase storage space at times and would not want to remove all of that cold mass.