Compressed air cooling

[AO1958]

Hi All,
I am new and I hope not to make you lose time.
I hope to have posted thread in the right forum.

I am facing with the dimensioning of an heat exchanger that utilizes air as primary fluid.
In shorts, it is an air-air heat exchanger that it is utilized to cool compressed air.
Both flows and inlet conditions are known.
I have looked to past post, but I have not found any reference concerning the cooling of compressed air.
I suppose that also the water content in the air plays its role in the heat exchange calculation but honestly, I have no idea about how dimensioning this heat exchanger.
Please, can anybody send me a tip, a link, an example or a literature reference to refer to ?

thanks a lot

 

[BigInch]

If you're looking for fin fan info, this is the place,

http://www.hudsonproducts.com/products/finfan/techpapr.html

After you've understand the technical stuff, down the software,

http://www.hudsonproducts.com/download.html

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[AO1958]

Many thanks Mr Big Inch.

Please, may I ask you which heat exchanger type has to be used for this kind of application ?
A fin and tube or a different one ?
The tube diameter is larger than it would be if it would cool water ? I suppose it will, since density is different.



Many thanks

 

[BigInch]

There would be a lot of difference in the heat conduction across the pipe-fluid interface between water and a gas, which would require much more surface area for a gas.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Montemayor]

AO1958:

If you are proposing to cool a compressed air stream with atmospheric air, then Big Inch has given you one the top expert designers/fabricators in the field for this application and reading all their literature will help.

Your subsequent question(s)/query only cloud up or confuse the issue you first presented. If you are cooling air with air, then you are applying probably the worst heat transfer film coefficients as related to heat exchangers. Gases - such as air - have inherently terrible heat transfer film coefficients. That's why they are used as some of the best insulators in industrial applications. Because of this physical fact, your application will probably have to employ finned tubes in order to assist in mitigating the bad heat transfer qualities of the atmospheric air. More heat transfer area helps to compensate for the sorry heat transfer film coefficient. This is practically nothing to do with the tube's diameter. Pressure drop through the tubes, however, do have a lot to do with the tube diameter.

If you are going to consider cooling the compressed air with water instead, then you inherit a BETTER and MORE EFFICIENT heat transfer due to the better heat transfer film coefficient that water (or most liquids) has. Therefore, you do not require finned tubes on the water (shell) side. Again, your tube size and arrangement depends on what you can tolerate as a pressure drop through the tube side (assuming that is where you place your compressed air). All of this information (plus more) constitutes what Big Inch described as "understand the technical stuff".