Originally posted by DaBit
Sure, suction pressure is within manufacturers limits, but discharge is not.

Now I wonder whether the 55C/131F maximal condensing temp with R134a is based on maximum pressure, or maximum temperature? At such high condensing pressures and low evaporation pressures, discharge heat increases. Or the motor might just overheat since more torque is required from it.

I would try to keep condensing pressure as low as possible.
DaBit, what you have to consider, is the density of the refrigerant. I'm am only speaking in terms of the concept, but if you have R-134A at a -20 S.S.T., and compare to R-404A at -50 S.S.T., what is the differences or similarities of the mass of the gasses at those conditions? Even though the straight math (pressure ratio) of the two applications may present itself as a problem upon first evaluation... you must further evaluate the mass flow that results from the two different scenarios, and perhaps you will arrive at a common basis for each application. The limits of the DP across the compression cycle (terminology?) may well be affected by the differences in the mass of the refrigerants at the different applications (densities).


Does that make sense?.... PROFESSOR!!!!!!