Compressor Intercooler

[Technome]

I am not an Engineer

Just purchase a 5 hp Curtis two stage compressor...

I want to create an intercooler and aftercooler for this compressor. Both coolers will be made from a copper pipe loop (two 1/2" L type rigid each loop), buried 5 feet in the earth. Moisture removal will be taken care of in both cooling loops. Air leaving the copper loops should maintain approx 50F year round average, removing most of the moisture, a good deal of heat,increasing the air density to the second cylinder in the intercooler stage
Question...
As to the intercooler, will the extra air capacity of the copper loop (guessing a couple CF) negatively affect the operation of the compressor in any way.

Thanks
Paul Meiners

 

[Bribyk]

What do you hope to accomplish by cooling the air, moisture removal or do you require it at a certain temperature for its application?

How is the water going to be removed from the tubing?

Also, if by "CF" you're referring to a cubic foot, that would be a HUGE amount of tubing.

A few more details would be nice but I don't think this is worth your time/money.

 

[zdas04]

Lets get real here. Let's say that you are at sea level and want to use your 5 hp to do 4.5^2 compression ratios (call it zero to 284 psig). Doing that requires 215 hp/MMCF so you can compress 16 SCFm with your 5 hp. That number is small enough that you can very likely just rely on ambient heat losses to keep everything cool enough--there really isn't any reason to bury a couple of hundred feet of water trap.

David

 

[Montemayor]

Technome:

Both Bribyk & zdas04 are correct in their evaluation of what you are proposing.

You can simply "bury" the copper tubing and expect it to cool off the air. The subsoil around the coil will eventually reach an equilibrium temperature close to the hot temperature exiting the 1st & 2nd stage - at which time there will be negligible heat transfer taking place. The sod around the tubing will act as a hot insulator. In short, what you propose doesn't work as far as heat transfer.

Then comes the reality of what do you do at the outset when there is some initial cooling and subsequent condensation of water vapor between the 1st stage discharge and 2nd stage suction. If you don't succeed in selectively draining this water, it will enter the 2nd stage and wreck it. So the results of a naive and hopeful solution becomes the demise of the total compressor.

I've done what you desire, but I did it with an air fan and interstage and after-cooler water separators and drain valves. That, I know works; but it will cost more than just burying copper coils.

 

[Technome]

Thanks for the post guys...
Yes, a couple CF is over estimating.

Moisture removal is the prime objective.
I have the option of burying the pipe loops, without the cost of digging, as it would be buried by fill at a site.
Condensation, I realize would need removal on both loops and that damage would occur if any water hit the second stage.

"The subsoil around the coil will eventually reach an equilibrium temperature close to the hot temperature exiting the 1st & 2nd stage - at which time there will be negligible heat transfer taking place.
Good point.
Guess the most practical is just to get a refrigeration air dryer.

Thanks

 

[Bribyk]

Even if you did get perfect heat transfer, the minimum ISA-recommended dew point of instrument air is 35 degF. If you're concerned about moisture content you should check out the ISA standards.

 

[unclesyd]

There is essentially no capacity in a refrigeration dryer to absorb liquid water and normally very little capacity to absorb water vapor. These dryer are made to absorb a very small amount of water vapour at the initial filling and any water from decomposition of the refrigerant.

You will need a liquid trap and a dryer that can be regenerated.

http://www.ecompressedair.com/index.shtml

 

[Technome]

I meant air dryer, as in refrigeration based.
Thanks

 

[unclesyd]

Gotcha, that's a whole lot better than what I assumed.

I just wanted you to be aware that dry air becomes very expensive very quickly.

 

[Technome]

Yes, any exchanger, refrigeration or membrane dryer has a hefty price, seems like it will cost 50% as much as the compressor to have a dry output.

 

[unclesyd]

If you don't need the dry air all the time look at splitting the system so as to run the dryer only when needed.