| Duracool in the original Norcold refrigerator [message #93174] |
Sun, 25 July 2010 12:19  |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma:
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Senior Member |
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For a long time I have been wanting to try R 12a (Duracool) in one of the original Norcold electric compressor refrigerators to see if it would reduce the power consumption to any significant degree.
I was given a much more recent Norcold with a swing motor compressor, which had failed. It is a model made in the early 2000's and used R 134a as the refrigerant. All of the GMC supplied Norcold units from the '70's used R12. A complete search of the net found no sources for purchase of the compressor, apparently it is a OEM item only. So, the refrigerator was totally useless.
I then found a $1 water cooler which also used R134a at a Goodwill store. It ran and cooled just fine. I decided to try to put the small 120 volt compressor from the water cooler in the Norcold refrigerator, and charge it with R 12a (Duracool). The idea here was to see if I could build an electric refrigerator which used a 120 volt compressor which I could run on an inverter when necessary, and have the power consumption less than the original Norcold swing motor compressors. I had previously determined that anything less than 30 watts per hour would be my goal. (see: http://www.bdub.net/Refrigeration_in_the_GMC.pdf)
I plumbed it up, evacuated it, charged it with Duracool and set the suction pressure about 0 psi, as I wanted low temps of around zero degrees F in the freezer compartment. This, you should note, is a lower suction pressure than we use in the GMC dash AC unit as I want to have colder temps in the evaporator of the refrigerator.
Results have been mixed. The combination did work, and the freezer and main box came to reasonable temps. However the compressor had to run full time to do that, with a power consumption of just over 50 watts per hour. That did not meet my goal at all. I think the compressor is just too small for the job. It was meant to cool a small amount of water in a water cooler, not a larger refrigerator box with freezer. So, it just never shuts off. I have no idea if the Duracool helped with the power consumption, but it does work in the 134a system.
I am now on the lookout for a somewhat larger compressor to try out, one that may take 70 or 80 watts to run, but which would cycle on and off to keep the temp right and have an average consumption of less than my goal of 30 watts per hour.
It is a fun experiment, and I will keep you informed if I make any progress.
Rob Allen
former owner of '76 x-PB
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