View Full Version : Long suction line infect

22-06-2017, 02:16 PM
My chilling plant suction line is 70 meter and a other same plant suction line is 20 meter my plant efficiency is not same that plant . So I want to know long suction line in effect to efficiency ?

22-06-2017, 06:47 PM
the efficiency should not be the same
difference between them 50 meter and in 70 M you have more losing pressure than 20 M
in long piping returning system oil and slope is very - very important
in system you should have enough oil to cover your oil moving in system and also in suction line you should put suction separator to avoid damaging compressor from returning oil and liquid
also if you have pumping system you need more head pump in 70 M than 20M

22-06-2017, 09:44 PM
The longer the line, you can have a pressure drop, if line size is to small.
Line should be sized for low pressure drop.
If you can install gauge at compressor & another at chiller evaporator to see how much pressure drop.
Is there anything else in longer suction line, like valves?

23-06-2017, 07:15 PM
the system with 20 meter pipe was probably calculated with a 20 meter pipe, and they took into account the pressure drop in the length of the suction pipe.

When they calculated the 70 meter pipe system, they should have done the same.

I'm sorry I can't calculate it for you.

But if you provide the dimension of pipes, the length, type of refrigerant and operating pressure/temperature of the system, I am sure there is someone here who could do it for you :)

24-06-2017, 01:05 AM
If pipes have the same diameters, refrigeration plant of longer pipe should operate at lower suction pressure to provide required cooling. Lower suction pressure means lower energy efficiency.

24-06-2017, 12:11 PM
Segei sir thanks for comments . But I want to know only when suction line is longer . Plant efficiency is down ?

24-06-2017, 12:29 PM
My suction pressure is 30psi and discharge is 235 psi and pipe diameter is same 100mm I have a chilling tank and my suction line is longer that's open in chilling water And it had every time covered with ice so I think compressor More work to longer suction line That open of chilling water level.

25-06-2017, 11:46 PM
Are you sure that you talk about efficiency? Efficiency is energy use per unit of refrigeration. I think you talk about capacity. Plant with longer pipe will run longer because greater pressure drop in suction line.

26-06-2017, 02:05 AM
From your description I am assuming the longer suction line is in the process water. Since you stated that it is ice covered, you have another load on this system. The heat removed from the water to form the ice is added to the chiller load. The extra 50 meters of suction line adds pressure drop to the system, the usable refrigeration at the far end of the suction line run maybe 65% or less.