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ssk7899
24-08-2011, 01:44 PM
Dear Forum

I like to know up to what temperature can ammonia refrigerant can achieve .
I like to design for -40 DegC with Ammonia Refrigerant is that possible.

I came to know that it is possible in two stage system is that true?

please give me suggestions

Thank you.

Magoo
25-08-2011, 04:50 AM
Yes they can run down to -50'C air temp., with two stage systems.

Magoo
25-08-2011, 06:05 AM
Forgot to mention that -40'C temps are quite acheivable with single stage screw compressors with sub-coolers.
magoo

Rajkumar
25-08-2011, 11:39 AM
Yes you can acheive easily with Ammonia using single stage compressor / two stage (booster / high stage) reciprocating compressors.

mbc
26-08-2011, 06:13 AM
temperature is not very important , main thing is :
what kind liquid do you want to cool

ssk7899
26-08-2011, 08:12 AM
Thanks for your suggestions

I like to cool methanol fluid , can any one provide me normal diagram how to design .
please do me need full.

lowtempman
26-08-2011, 01:20 PM
Several different basic designs are possible. Depends on the amount of cooling desired, btu per hour? or other measurement in metric units kw per hour etc?. Evaporator can be plate and frame, direct expansion shell and tube, or flooded shell and tube. Compressor can be recip or screw. Condenser can be water cooled, evaporative air/water or even air cooled. Without getting into details there are several pieces of equipment that nay be required such as receiver, economiser, interstage desuperheater to cool discharge from low stage compressor.

Methanol a fairly good choice for the fluid. Low cost, low viscosity, low freezing temperature, but poor specific heat and of course, flammability may be an issue depending on the water/methanol concentration.

If you are trying seriously to design a system you had best have an expert help you out