CW Supply & Return line sizing question

[ProjectEng]

I want to run new cooling water supply and return headers for a few air compressors. Headers will be taken off very large CW supply/return plant headers.

I have sized the supply header to the compressors.

Is it recommended to increase the return header diameter by one pipe size to promote flow through the oil coolers? Or is it acceptable to stay with the same line size as the supply header?

Thanks.

 

[KiwiMace]

If by 'headers' you mean 'branches' to each coil, there is no benefit in increasing supply or return pipe diameters if you have sized for your intended branch pressure drop.

I'd add that there is a difference in how you size 'headers' vs 'branches': I'd refer to a header being the same as a manifold. The way you size these should be to minimise pressure drop in the header between the first and last branch - ie, evenly balance the flow through each branch.