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ivonaumov
30-01-2014, 09:43 PM
Hello people,
I hope you can help me. Maybe my questions have them set in another thread but have not found answers to them. I have a refrigeration system with three semi-hermetic reciprocating compressor of R 134A. I need to calculate the diameter of the pipes.
My question is what is the maximum pressure loss in suction, pressure, liquid and condensed pipes. Thank you.
The Viking
30-01-2014, 11:13 PM
0, 0 and 0 respectively.

Trust this answered your question.

Seriously thou, you can't design a system and it's pressure differentials based on the information you gave us.
In an ideal system there are no pressure drops in the pipework, in real life it is and therefore the components of the system has to be selected to allow for this...

:cool:
ivonaumov
31-01-2014, 08:45 AM
Okay, here's more information.
Parameters under which the system works: tо=-2ºC; tc = 45ºC. Lengths of pipe are: suction and liquid - 10m, and plenum between the condenser and receiver - 8m. Compressors are 3 each with 65 kW cooling capacity.
Do you need more information. I will give you any more information is needed to get the answers that I need.
Thank you.
The Viking
01-02-2014, 12:22 AM
OK,
Let me put it another way.
Select an evaporator, your 3 compressors and your condenser.
Select what you think is the right pipe sizes and calculate the pressure losses you will get and then go back and check if your system is within it's design parameters and if you are within the design envelopes for your compressors, your evaporator and your condenser (not forgetting your expansion device).

If you are within the design envelopes and will get the required duty out of it then you haven't got a problem, if not you will have to use larger pipe sizes and re do the calculations until you find a system that will work. (but don't forget that you also need to look at the velocity of the refrigerant, if it drop too low then you will get problems with oil circulation)

:cool:
moideen
01-02-2014, 06:56 AM
please go to this link and down load a software of calculating pipe size.i think it may help you.

https://www.mediafire.com/folder/59o6n80vs98at/soft