Choose Parts for an 18000BTU/h Refrigeration Cycle: Who Sets the Temperature?

[eaboujaoudeh]

Hey All

Suppose ur designing a refrigeration cycle. if u go to the market to choose parts for an 18000BTU/h circuit. The compressor has different ratings according to the entering temp and exit temp, then u have the thermal expansion valve which is also rated in BTU/hr depending on entry and exit pressures, the Evaporator and condenser are also rated according to the BTU/h scale depending on the evaporating and condensing temperatures..
my question is, who sets the liquid and evaporating temperatures?
how could i be sure that my cycle would be a high temperature cycle? or medium, or low temperature!

 

[Danger]

Sounds like a job for the Russman.

 

[NoTime]

my question is, who sets the liquid and evaporating temperatures?
how could i be sure that my cycle would be a high temperature cycle? or medium, or low temperature!

1) The liquid and gas phase temps are primarily determined by the characteristics of the operating fluid.
How you implement those characteristics into your design sets the operational temps.

2) I don't know a lot about refrigeration, but I think you need to clarify this question.

 

[eaboujaoudeh]

using R-22 for example...what my question means is that to design a refrigeration cycle u select the pieces according to capacity, but what makes sure they wil operate at a certain condensing temp and evap and not another?