havc superheat and subcool reads?

Answer 1

The second answer is correct. But superheat and subcooling are relative to equilibrium temperatures and pressures. A certain pressure there is a single equilibrium pressure. If the gas phase is higher than the equilibrium temperature it is said to be superheated, the superheat is the temperature difference.

If a liquid is below the equilibrium temperature for a given pressure it is considered subcooled.

Answer 2

superheat is the heat absorb by compression and is basically the temp above your saturation temps on your pressure/temp (PT) chart. For instance: All info for R-717 Your compressor discharge pressure is 150 psig, at 130 deg. F. Saturation temp for 150 psig is supposed to be 85 deg. F therefore you have 45 deg. of super heat. Sub cooling is the same it but it deals with the temp below the saturation temp. of liquid. For instance with R-717 a pressure of 5.4 inches hg should be a temp of -35 deg. F but if your temp is at -45 deg. F with a pressure of 5.4 inches of hg then you have 10 deg. F of subcooling.

Answer 3

superheat is the difference between the actual temp of the suction line and the conversion temp of the pressure temp chart subcool is the difference between the actual liquid line temp and the conversion temp of the pressure temp chart