When drawing a PH diagram of an operating system, how is placement of the metering device line determined?
A) The metering device line starts where the compressor line crosses the temperature of the liquid line and then drops straight down until it crosses the condenser line.
B) The metering device line starts where the condenser line crosses the temperature of the liquid line and then drops straight down until it crosses the compressor line.
C) The metering device line starts where the condenser line crosses the temperature of the liquid line and then goes straight across until it crosses the compressor line.
D) The metering device line starts where the condenser line crosses the temperature of the liquid line and then drops straight down until it crosses the evaporator line.
[Ques. 2] How is placement of the compressor line determined when drawing a PH diagram of an operating system?
A) The compressor line starts where the evaporator line crosses the suction line temperature and follows the constant enthalpy lines up until it crosses the condenser line.
B) The compressor line starts where the condenser line crosses the suction line temperature and follows the constant entropy lines up until it crosses the evaporator line.
C) Measure the suction-line temperature entering the compressor. Find where the evaporator line crosses this suction line temperature in the superheated area.
D) The compressor line starts where the evaporator line crosses the suction line temperature and follows the constant quality lines up until it crosses the condenser line.
[Ques. 3] How do the three position service valves differ from other valves?
A) They have no closed position. B) They are leakproof, if undamaged.
C) They have multiple closed positions. D) They are spring-loaded.
[Ques. 4] What is the refrigeration effect of a system if the liquid entering the evaporator has an enthalpy of 60 BTU/lb and the vapor leaving the evaporator has an enthalpy of 110 BTU/lb?
A) 110 BTU/lb + 60 BTU/lb = 170 BTU/lb B) 110 BTU/lb/60 BTU/lb = 1.83 BTU/lb
C) 110 BTU/lb - 60 BTU/lb = 50 BTU/lb D) 110 BTU/lb
[Ques. 5] How is placement of the condenser line determined when drawing a PH diagram of an operating system?
A) Draw a vertical line across the saturation curve on a constant enthalpy line equal to the system high-side absolute temperature.
B) The condenser line can be drawn anywhere that crosses the saturation curve as long as it is a horizontal line.
C) Draw a horizontal line across the saturation curve on the constant pressure line equal to the system high-side absolute pressure.
D) The condenser line is always drawn on the horizontal line representing 275 psia absolute pressure.
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