12/24/120 volt fridge freezer efficiency comparison (datasheet and youtube videos)

[dzl_]

I've been researching fridge/freezer efficiency, I know its a topic of interest (and confusion/debate) for many people.


I came across a series of tests done by expedition extreme on youtube (and a pdf spreadsheet of their findings).



They performed 1 and 2 hour cooldown, cycling, insulation, and 12, and 24 hour power draw comparisons. With 4 fridges (Snomaster, Arb, Waeco, and a 26 yr old Engel) and ambient temps in the mid 70's [73-78].


Set to 0c (32 fahrenheit), the fridges consumed between 24 amp hours on the low end to 30 amp hours on the high end, over a 24 hour period (290-360 watt hours).



The best performing in this test was the Waeco and the worst performing was the 26 year old Engel, strangely, in the 12 hour test the Engel tied for best performance.

[o1marc]

Those tests were probably done stationary parked in a flat lot somewhere. I wonder how those numbers work in a moving environment

[BarnYardCamp]

How would a moving environment effect the efficiency? Unless of course the moving environment created different operating environments...hotter or cooler.

[dzl_]

Originally Posted by o1marc

Those tests were probably done...

No need to guess, spend a few minutes watching the videos or reading the spreadsheet if you are interested, the methodology is pretty clear.

The tests are: stationary (in a garage), climate controlled (73-78f ambient), 12v, nearly empty (single water bottle), using both built in and external temperature sensors. Its not representative of real world use (there are way too many variables involved in that), but it provides a baseline comparison that is valuable and hard data which is lacking. This episode goes over the methodology.

I'm curious what effect you expect moving might have? There are many variables which would change the power draw/efficiency (ambient temp, temp fluctuation, thermal mass of contents, how many times the door is opened, venting, etc), I never considered that being in a moving vehicle would be one of them.

[jofred99]

I'm missing the info about voltages used in their findings. Watts are watts, but amps used will vary based on the voltage.


Has anyone seen seen usage information for Sun Frost or SunDanzer units?

[dzl_]

Originally Posted by jofred99

I'm missing the info about voltages used in their findings. Watts are watts, but amps used will vary based on the voltage.

12V (if you want to know more about the methodology see here)



The spreadsheet is more of a reference sheet for those who watched the videos, you won't get a good idea of the methodology from it alone. It would've been nice if they spelled out the methodology in writing as well though.

[o1marc]

Originally Posted by BarnYardCamp

How would a moving environment effect the efficiency? Unless of course the moving environment created different operating environments...hotter or cooler.

Nevermind, I was thinking of the propane fridge issue.

[dzl_]

Originally Posted by o1marc

Nevermind, I was thinking of the propane fridge issue.

Ah okay, that makes more sense. Yeah, that is not an issue with the 12/24/120 fridges. You don't have to be close to level like with the propane units, and afaik 'movement' shouldn't doesn't effect them.

[Tomas]

I would argue the most relevant test is consumption over 24H where the Waeco and ARB performed about 20% better than the rest.

Not sure if the Snomaster comparison is fair. It's 42L compared to the others at 40L which is 5% more volume. Not much more but still.

[dzl_]

Originally Posted by Tomas

I would argue the most relevant test is consumption over 24H where the Waeco and ARB performed about 20% better than the rest.

I would agree with you (I really wish that on top of the tests they performed, they would've done a longer term 1 week+ test that more closely approximated real world usage).


But its worth noting, if you look closer at the data, the ARB doesn't do as good as it first appears because it was the only fridge in the selection that was not able to bring the water to the set temperature in 24 hours. It was only 2.3 degrees C above the set temperature, but if you do the math it comes out to using 17% less energy to attain a 15% higher temperature compared with the average of the other fridges, so basically break even.

Not sure if the Snomaster comparison is fair. It's 42L compared to the others at 40L which is 5% more volume. Not much more but still.

Yeah, that skews things a bit. Adjusting for that 5% the Snomaster would have used 27.75 Ah in the 24 hour test.


If they did a followup test I would love to see a more 'real world' long term test, where they set the thermostat to fluctuate between a high daytime temperature and a cool nighttime termperature, and filled it with more than a single water bottle, and tested over a week or more.

[kidharris]

Originally Posted by dzl_

I would agree with you (I really wish that on top of the tests they performed, they would've done a longer term 1 week+ test that more closely approximated real world usage).


But its worth noting, if you look closer at the data, the ARB doesn't do as good as it first appears because it was the only fridge in the selection that was not able to bring the water to the set temperature in 24 hours. It was only 2.3 degrees C above the set temperature, but if you do the math it comes out to using 17% less energy to attain a 15% higher temperature compared with the average of the other fridges, so basically break even.






Yeah, that skews things a bit. Adjusting for that 5% the Snomaster would have used 27.75 Ah in the 24 hour test.


If they did a followup test I would love to see a more 'real world' long term test, where they set the thermostat to fluctuate between a high daytime temperature and a cool nighttime termperature, and filled it with more than a single water bottle, and tested over a week or more.

I gotta admit that I did not watch every minute of these vids because I lost interest when I realized during #3 that their methodology was somewhat lacking. It would take too much time to go over tall of the flaws that I saw, but I concluded that their results were bogus and blah blah blah blah.


A dead visual give away was having the units running side by side touching was allowing the center 2 units to take advantage of the neighbors insulation and the 2 outside ones having an extra side exposed to the garage temps.


As far as the ARB result you mentioned " 2.3 degrees C above the set temperature". One of the flaws that I saw was that they did not take the thermostat cycle settings into account. Some are adjustable, some are set. For instance, lets assume that it is adjustable in degrees c for ease of discussion.


EX1 if you have set the stat cycle to 2 degrees above and 2 degrees below, than set the temp to 0 (zero) degrees than it would turn on at +2 and turn off at -2 (stat set to 5, then on at 7, off at 3). There could be up to a 4 degree temp difference depending on when you check it.



EX 2 If the cycle is set at 1 above & 1 below and the stat set to 0 it would turn on at +1 and off at -1. (stat set to 5, then on at 6, off at 4) The ARB could have been in between the on & off points if the stat wasn't very accurate. There could be up to a 2? degree temp difference depending on when you check it.


EX 3 If the cycle is set at 0.5 above & 0.5 below and the stat set to 0 it would turn on at +.5 and off at -.5. (stat set to 5, then on at +5.5, off at +4.5) There could be up to a 1 degree temp difference depending on when you check it. At this setting the temp would be fairly accurate but it may turn on every time you open the door. This setting would also bring the sensitivity of the stat & thermometer into question.



A stat has to have on and off cycle set points or else it will just sit there and cycle on and off and burn up the compressor. The further apart the points are the less the compressor cycles on and off.


How far away from the evaporator their thermometer was could also account for this reading difference.

[Mudhutwarrior]

Test is misleading because they were run without a load. "Water Bottle"


Next time they should discuss their test with an engineer before wasting time.

[dzl_]

Originally Posted by Mudhutwarrior

Test is misleading because they were run without a load. "Water Bottle"


Next time they should discuss their test with an engineer before wasting time.

Well the test isn't exactly misleading since the reason you know the only content was a single waterbottle is because they told you the content was a single water bottle. Its hard to argue they mislead you (maybe I'm just nitpicking language). But I'd agree that it doesn't accurately represent real world usage (then again testing seldom does).



Inaccurate at measuring real world usage, yes definitely. Could methodology have been better, yes definitely. Still a comparison that is worth more than nothing. I've been doing my research and I haven't been able to find anything better, have you? If you have I'd love to see it because I also want to see a better comparison of real world performance.

[dzl_]

Originally Posted by kidharris

A dead visual give away was having the units running side by side touching was allowing the center 2 units to take advantage of the neighbors insulation and the 2 outside ones having an extra side exposed to the garage temps.


As far as the ARB result you mentioned " 2.3 degrees C above the set temperature". One of the flaws that I saw was that they did not take the thermostat cycle settings into account. Some are adjustable, some are set. For instance, lets assume that it is adjustable in degrees c for ease of discussion.

Good point about placing the fridges too close together


Regarding the cycling of the thermostat, that's also a good point but most likely not the case here. The ARB's ambient inside air temperature was 0c but it was only able to cool the water bottle down to 2.3c. Water will fluctuate much much slower than air and wouldn't be significantly affected by normal cycling. So cycle parameters probably don't explain the difference in temperature in this case.


https://expeditionextreme.com/wp-con...geTest2019.pdf