Compressor in Air Conditioning System

Not advisable.

Given that the fluid being compressed in an air conditioning system is one with different properties to air, it would seem highly inadvisable at first sight.

What "we" do is indeterminate at this time, as the reason for doing it is as abstruse as it is obscured.

Even if you solved all other problems you need an environmentally sealed compressor. Air compressors generally are not (because they don't have to be). S.M.

On the back of a napkin, no problem, they both compress a gas to a higher pressure. In reality, the gases have different properties, you really don't care if there are small air leaks since you have an infinite supply of air, but not so if the working fluid is a refrigerant. However, if your question was reversed, then the answer is "yes, you can use an a/c compressor as an air compressor (or vacuum pump for that matter)".

You are correct. We used one on the farm for many years. As long as there is oil in it and that it doesn't suck in too much dust it will work OK.

Make sure that you have an over pressure valve and a pressure switch to stop it.

Most AC compressors are relatively slow but are very quiet.

They are not very good when starting under pressure. We usually had to get the pressure below 40psi before the compressor could start without tripping the overload.

Don't forget that compressed air is dangerous. Tanks explode like a bomb. Use over pressure protections.

Isn't it all ready conditioning the air, changing the pressure.

I would say an A/C compressor is just as ordinary, if not more so, than your 'ordinary compressor'. In fact, there are very many different types of compressor (screw, scroll, centrifugal, piston, etc.) all designed for very different applications and fluids. It's the same with pumps, and you wouldn't want to be switching water, oil, fuel and washer pumps in your car. They are all pumps, but quite different.

'What is the difference...?' Too much to expound here. Try this, http://en.wikipedia.org/wiki/Gas_compressor , for a start.

Please Do not use an a/c compressor as an air compressor !!!!

I have advised that for 45 years and still people go right on and do what they wanted to do before they asked even when I try to explain that the clearance between the pistons and the head are in the two to three thousands range and an a/c compressor allows 4% of crankcase capacity to pass by the pistons and rings so when you allow air to enter an a/c compressor you can develop the same air/fuel ratio as a diesel and guess what you have an explosion and if it continues on into the crankcase it can be life threatening

I think the only reason some have got by doing that is that they used worn a/c compressors that could no longer develop pressures in the diesel range and I'm sure they also got by with using throwaway refrigerant tanks for air bubbles before they put one way hand valves on the tanks

A top notch compressor salesman called on me many years and he walked with a bad limp and after many years I finally had to ask about his leg
He said he had a 50 hp belt drive a/c compressor blow up and a piston and rod hit his leg I asked why it blew up and he said he was ashamed to tell me but finally admitted that he allowed air to enter the compressor and it dieseled and blew the rod and piston out through the crankcase wall

Maybe there are more in this forum that can share a story about the loss of a limb or a friends life that can convince you to buy and air compressor instead but then again maybe someone can convince me that all the people that warned me were wrong

I think OP suggested the reverse scenario. Air compressor converted to A/C. S.M.

I'm sorry this old man accidentally jumped up on the pedestal and started preaching against using a/c compressors for air service
I didn't understand the exact question posted and there may have been a little language
barrier between two posters from different countries for which I apologize but then again if I accidentally convinced one person not to do that it was not waisted time

Equipment designed for particular application should be used for that application only. It is a good professional practice. In air craft refrigeration air is bled from the compressor of the jet or gas turbine engine or is supplied from an auxiliary compressor source and cooled in an air heat exchanger . It uses reverse Brayton or Joule or Bell Coleman cycle.

The "difference" is using one is the correct thing to do, using the other is Mickey Mouse.

NO!!!!

That would be like I saw an air station storage tank being used as a Expansion Tank in China Town in San Francisco. As Tornado said "Not recommended".

NO period!