how do you work out the suction pressure and head pressure for a system. I am looking for air off of about 10c for a cellar cooling application
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how do you work out the suction pressure and head pressure for a system. I am looking for air off of about 10c for a cellar cooling application
forgive me, for i am not a technical man.
if you want air off at 10c, why not use an a/c system? insted of cellar cooling.
cheers
eggs
Considering most celler rooms wants to be at 10 - 12deg C why would you only want air off at 10 deg C?
If you know that air off is going to be 10°C then you can work out the suction pressure from the refrigerant being used. The head pressure depends on all sorts of things, fan control, refrigerant type, etc.Quote:
Originally Posted by Ianh
The question is ambiguous, what are you trying to achieve ?
Anyone remember 12? Cellar cooling was always 20-24 psi back pressure and about 95 psi head, get yourself a comparator and you can work out for yourself the temperature relationship. Transpose this to any of the 'new' refrigerants and ther's your problem solved !! O.K
Hi Ianh and Paddy , good evening , good morning . good day , how are you ??????
:cool:
For 10°C air out of the evaporator you must have an evaporating temperature of 5°C or below (but not 0°C because of frost build up). The best choice is te=2°C like it is in any water chillers. The evaporator must be sized with this evaporating temperature.
Then when te=2°C and the refrigerant say is R22 then with temperature-Pressure chart you can find the corresponding pressure (Pe). If the condenser is air cooled then measure the ambient air and add approx.12°C to it which will be your condensing temp.( if the condenser is sized correctly).
From the temperature-pressure chart find the pressure(Pc).
Suction and discharge pressures depend on the refrigerant used and also to the operating conditions (te,tc).