Chilled water system -Maximum Design pressure Vs Operating pressure
Chilled water system -Maximum Design pressure Vs Operating pressure
(OP)
Hi experts,
In expansion tank sizing software the following inputs required.
1. Maximum design pressure
2. Operating pressure
How to calculate these parameters?
Thank You
Timothi Albani





RE: Chilled water system -Maximum Design pressure Vs Operating pressure
BTW the word "maximum" is irrelevant. Your design pressure is your maximum pressure so you can't have a "minimum" design pressure...
Very vague question so very vague answer I'm afraid.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Chilled water system -Maximum Design pressure Vs Operating pressure
Thank you very much for your attention. Sorry for the vague question. This is what exactly I meant.
Is there any formula to find P1 & P2
For closed expansion tank
Vt = {((v2-v1)-1)-3αΔt)/((Pa/P1)-(Pa/P2))}*Vs
Vt= Expansion tank volume
P1 = Pressure at lower temperature
P2 Pressure at higher temperature
RE: Chilled water system -Maximum Design pressure Vs Operating pressure
you must get smarter than the software you're using.
RE: Chilled water system -Maximum Design pressure Vs Operating pressure
In your OP you say that you need P1 and DP. I think you also need to know expansion volume...
Normally to work out an expansion tank volume you start with your initial P1, work out the volume it expands due to increased temperature (hence you need to know the total volume of liquid you are dealing with), have your design pressure known and then you can figure out how much air volume is required to go from P1 to design pressure. You need to assume then how much volume you start with at P1 then add the air volume so that when the expansion volume fills the tank you end up with no more than design pressure. This is the relatively simple method - of course as pressure increases the density of the fluid changes a little bit and the volume of the pipes etc changes a little bit, but these are usually fairly small compared tot he expansion of the fluid. For expansion tanks it is better to be a little cautious.
If you know three of air volume, liquid expansion volume, P1 or P2 you can work out the fourth , but I don't think you can do this by reverse unless you assume a number for P1 or P2 or the volumes.
Sorry, but without guessing I don't think this will work.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Chilled water system -Maximum Design pressure Vs Operating pressure
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Chilled water system -Maximum Design pressure Vs Operating pressure
you must get smarter than the software you're using.
RE: Chilled water system -Maximum Design pressure Vs Operating pressure
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way