3 replies to this topic

[Faisal Ghafoor]

Can anybody tell any thumb rule for calculating compressor power for the required refrigeration duty of 350 Ton.
It is ammonia vapors from ammonia storage tank that need to be compressed/condensed and recycled back to tank. I know the total flow of ammonia vapors is 2.3 t/hr at -33C and 200 mbar. (~ 350 ton of refrigeration).

Site ambient condition is 41C. Condenser will be air cooled thru fin fan coolers, as there is no water supply at site. Compressor would be oil filmed screw compressor.  I need to roughly estimate the required electrical power of the compressor to be used for this work.

[breizh]

Faisal ,

Why don't you ask the vendors ( Trane, York , Carrier,...) they are manufacturing this type / size of equipment ?

 

350RT # 1230 KW refrigeration .

https://www.google.c...iller catalogue

 

http://webbook.nist....hemistry/fluid/

 

hope this helps

 

Breizh

Edited by breizh, 15 February 2014 - 08:20 PM.

[PingPong]

the total flow of ammonia vapors is 2.3 t/hr at -33C and 200 mbar. (~ 350 ton of refrigeration).

How did you calculate that 350 RT ? Based on 2.3 t/hr vapor I would expect an at least 25 % lower number, but maybe I misunderstand the system.

A process flow sketch of the system would be helpful.

 

Additional questions:

What is the pressure in the storage tank? Slightly above atmospheric?

If so, why is there such a big pressure drop between the tank and the 200 mbar that you mention for the vapor flow to the compressor?

It makes a huge difference for the power consumption whether the compressor suction pressure is 200 mBar or 1000 mBar.

Edited by PingPong, 15 February 2014 - 08:39 AM.

[Bobby Strain]

You can start with a Mollier chart for ammonia as the first step.

 

Bobby