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Fridge or A/C compressor?

Posted: Thu Jul 02, 2009 6:32 pm
by boyntonstu
Does it make a difference about size unit the pump comes from?

Is A/C small window unit OK?

Posted: Thu Jul 02, 2009 7:24 pm
by jonnyboy
Yes I'm pretty sure it was Mr.C who tore apart a mini fridge and didn't find anything on his although he lives in NZ brands could be a lot different there.

Posted: Thu Jul 02, 2009 7:40 pm
by POLAND_SPUD
if it has a compressor then it should be ok...
I am not quite sure what jonnyboy meant.. Mr. Crowley did tore apart a mini fridge just ot find that it didn't have a compressor but that doesn't mean that a small AC unit won't have one...

you'll have to check it to be sure

Posted: Thu Jul 02, 2009 8:09 pm
by ralphd
The more BTU'es the bigger the pump....to a point. In air conditioning, one compressor is used for a couple of sizes. What changes is the metering device, coils, air flow or charge. Air conditioning compressors are bigger than refrigerators and can pump higher because it is designed to pump R-22 now R 410a. Refrigerators use a lower pressure refrigerant, R-12 now R-134a but are much lighter than the other.

That refrigerator Mr.Crowley took apart may of been an absorbtion system which uses heat instead of a pump.

Posted: Thu Jul 02, 2009 11:04 pm
by Technician1002
Some mini (really small) mini fridges use a solid state Peltier effect cooler. They are very light, have no moving parts and are much less efficient than a compressor based cooler. Due to condensation and the electric module, corrosion of the module and early failure are common. It's probably why one was thrown out. It quit. They are very low BTU devices and never used in an air conditioner.

http://en.wikipedia.org/wiki/Thermoelectric_cooling

You can identify these as small units that are very light, have no freezer, and have a heatsink on the outside opposite the heatshink on the inside. They have no compressor or plumbing. The heatsinks have fans on both sides as they don't do well with a wide temperature differential.

Absorption systems are commonly used in RVs, as they use a boiler which operate off of either propane or and electric heater for 12 volt or mains power. The absorption systems have ammonia. Please don't ever open one. They run at very high pressure so the coils are steel instead of copper.

You can tell these apart as they have a boiler instead of a compressor and often have a couple sets of coils on the back instead of one. The boiler is electric, propane, or both.

http://en.wikipedia.org/wiki/Absorption_chiller

These almost always have an icebox in the top and can achieve good freezer temperatures.

Posted: Fri Jul 03, 2009 9:07 am
by frozebyte
How do you see if a fridge has a compressor or not? or can you like hear it?

Posted: Fri Jul 03, 2009 10:04 am
by Ragnarok
frozebyte wrote:How do you see if a fridge has a compressor or not?
Noise, and to a lesser extent weight.
Bigger units will invariably be compressor driven.

Posted: Fri Jul 03, 2009 10:38 am
by Technician1002
frozebyte wrote:How do you see if a fridge has a compressor or not? or can you like hear it?
Personaly, I look in the back. If it has a thin cooling tube radiator covering most of the back and a compressor underneath, it has a compressor.

If it has a Aluminum heatsink and fan, but no tubes, it's thermoelectric.

If it has a tube at the top with fins, a bunch of tubes in the middle at different angles, and a cooling coil below that, and an insulated box that is upright with or without a propane connection, it absorption.

The easiest is look up on Google the model number and see what refrigerant is used. R something is compressor. Ammonia is absorption. None is thermoelectric.