How can a PH diagram be used to select the system compressor? ...

[londonang]

How can a PH diagram be used to select the system compressor?
 
  What will be an ideal response?

Question 2

What are the constant quality lines?
 
  What will be an ideal response?

[macagn]

Answer to Question 1

Plot the system on the PH diagram
Determine the amount of heat picked up in the evaporator by subtracting the enthalpy of the saturated mix entering the evaporator from the enthalpy of the gas leaving the evaporator.

Divide this into the required system capacity to get lbs/min of refrigerant Calculate the required gas volume by multiplying the volume of the gas entering the compressor times the lbs/min
Determine the compressor operating pressures from the condenser and evaporator horizontal lines.
Match compressor volume at the determined operating pressures

Answer to Question 2

The constant quality lines start at the bottom and extend upward toward the critical point located in top center of the saturation curve. These lines represent the percentage of vapor in the saturated refrigerant.

[londonang]

TY

[macagn]

You're welcome