Help needed on Sequence of operation on a Cold-Storage

Respected All,
i am a Automation Control Systems Engineer(PLC,SCADA,VFD..etc) i had undertaken a Control systems Project for a Cold storage Plant, i had 0 experience in Refrigeration Plants,
i need clarifications & advice's on Sequence of operation. configuration of Plant is
1.) 7 Cold-Chambers ( for storing vegetables,Cheese,ice creams,ready to eat products)
2.)3 reciprocating compressors ( 2- KC-42,1-KC-21)
3.)2-WATER-COOLED CONDENSOR
4.) Temperature has to be acheived -30*c
5.) Refrigerant is AMMONIA.

I Need to design the logic for Starting of the compressors based upon SUCTION PRESSURE.
so if anybody can explain me the relation of temperature & Suction pressure.

THANKS for any help

sriji, Pressure & temperature are related. A pressure temperature chart is required for ammonia, you should be able to find one on internet. -33deg C = 0kpa pressure. Also suction pressure/temperature have to run colder than lowest required room temperature, so maybe for -30 C room you would have suction at approx. -35 to -36 C suction pressure equivilent

Do not try to re-invent the wheel. Also do you have enough knowledge around you to safely operate NH3 plant?

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Originally Posted by Brian_UK

Do not try to re-invent the wheel. Also do you have enough knowledge around you to safely operate NH3 plant?

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Thanks for the reply Sir, i don't have any experience in refrigeration Systems, i have experience in MACHINE AUTOMATION(CNC,SPM,etc..) only,http://www.refrigeration-engineer.co...es/redface.png i am not able getting a proper support from the Local
Technicians, so i have to learn everything on my own.

Thank you very much for your reply sir, Please forgive me for asking very silly questions, on what basis do i need to start a compressor.

Hello sriji,

There are various methods and schemes I expect, can I point you to some documentation that may help you?

Read some from Danfos which gives descriptions of what there controller read and write to operate compressor and fans etc..
http://www.danfoss.com/Products/Cate...ddde24342.html

Quote:

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Originally Posted by Brian_UK

Hello sriji,

There are various methods and schemes I expect, can I point you to some documentation that may help you?

Read some from Danfos which gives descriptions of what there controller read and write to operate compressor and fans etc..
http://www.danfoss.com/Products/Cate...ddde24342.html

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Thank you very much for your help Sir.