Refrigerator conversion


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Old 02-14-12, 08:19 AM
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Refrigerator conversion

Can I take a refrigerator system, change the evaporator coil and make a small air conditioner?
 
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Old 02-14-12, 02:54 PM
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No you can't.
Refrigeration and a/c compressors are designed to work in a very narrow temperature range.
One designed for a fridge is a low temperature application while a/c is considered a high temp application and would overheat if not operated within its temp range..
Plus, the cooling capacity of a fridge compressor is only a fraction of what it takes compared to a/c use.

Besides this, working on refrigeration systems requires you to be certified and you would need some costly equipment.

Better get a fan and a block of ice!
 
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Old 02-15-12, 06:26 AM
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Refrigerator Modification

I see lots of refrigerators with finned coils for cooling the air. The small refrigerator we have only has the freezer unit as it's evaporator, which stays frosted over and does not cool air efficiently at all. What I was proposing doing is swapping the evaporators (having it done by local technician) so I could cool the air, and circulate the air through a cabinet to maintain the cabinet temperature. The cabinet is custom made and well insulated, similar to a refrigerator, just designed to store a different product; not food. The air would be a closed, recirculating circuit. The air volume inside the cabinet with the product is only about 12 cubic feet and I need remove about 10,000 BTU's in 8-10 hours. The "normal" temperature range inside the cabinet is to be maintained between 65 and 70F. My boss says he has done the calculations and the small refrigeration unit has plenty of capacity. The compressor is rated at 735 BTU/hr. My calculations say we need more capacity and we'd be better off modifying a window AC unit. Who is right?
 
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Old 02-15-12, 11:20 AM
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Your boss may have done some calculations but there are other factors he has no knowledge of.
I'll repeat what I said but maybe I can say it a bit differently.

A compressor in a refrigerator is designed to operate at a low evaporator temperature and the btu capacity you quoted will be at the temperature it was designed to operate at.
When you try to operate it with a cabinet temperature of 65 degF you will be operating it in a high temperature range which will have a high temperature return gas temperature and in short order burn out the compressor.

An airconditioner compressor is closer to the range you want to operate at.
Here is a link to a control that may help you and search because there are others.

You are really speaking in terms that are too general to be of much help.
What exactly and how much are you trying to cool?
And, yes your boss needs to apologize for not believing you!
 
 

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