Math and another compressed air lines idea

[chase237]

In the spirit of beating compressed air lines to death I have a mathematical question about the benefits of volume and dry air.

A couple months ago I found some 1 1/4" copper pipe for a steal, OSH clearance. I picked up 3 10 footers and a couple handfuls of different fittings. All for the express purpose of building a non engineered air separator / dryer, even though I live in a relatively dry climate.

So since a 10 ft length of 1 1/4" equates to 49.1 cu. in. and a 10 ft length of 3/4" equates to 17.7 cu. in. the math comes out to a 10 ft length of 1 1/4" being equivalent to 27.7 ft of 3/4" My plan is use the big stuff right off the compressor then run 3/4" around the shop for the perimeter and drops.

Will this volume be a benefit or a detriment?

I don't use high volumes of air but I do want it dry and the price was right on the copper. Thoughts.

 

[Abeo]

A few things to think about:

-Expanding air will lower the temperature, compressing raises it. This may not have a great impact going from 0.5" (or whatever comes off the compressor) to 1.25", but it's in the right direction.
-Slowing air (by having the same CFM in a larger diameter pipe) allows more time for thermal transfer (and hopefully, lowering the air temperature enough to let water condense)
-Larger diameter pipe will have less pressure losses, but if you are already at 3/4, then I don't see much of an impact

Personally, I'd throw on a ****** cooler (or 2) with a drip leg before the air hits the tank. That way you get the most heat (and therefore, water vapor) out of the air before it has a chance to condense in the lines or tank. The extra large tubing after would just be gravy.

 

[bochnak]

Ever since I switched from an oil-less to 2 stage 80 gal, my moisture problem is gone. I have a refrigerated air dryer that I never turn on.

So let me ask, what kind of compressor do you have?

 

[stonesfan68]

There won’t be much volume in the pipe but it won’t hurt anything, either.

 

[teamextreme]

The purpose of the long lengths of piping is to reduce the air temp in the lines. While your ten foot stick of 1.25" pipe has the same volume as a much longer piece of 3/4", it doesn't provide the same heat transfer because there is no where near the same surface area to do so.

 

[chase237]

Compressor is a single stage Porter Cable, 6hp, 80 gallon. 175 psi, 15.6 cfm @ 100 psi.

I think the heat from the single stage may be a contributing factor in the moisture that condenses in the tank.

We just moved so I'm building from scratch and the copper was a great deal.