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!!!