Refrigeration & Air Conditioning interview questions
27 real Refrigeration & Air Conditioning questions from the Mechanical Core bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Coefficient of performance?
Junior
A.R-22 phase-out under the Montreal Protocol and HFC reduction under the Kigali Amendment are driving Indian ACs to R-32 and R-290
B.refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
C.ratio of refrigerating effect to compressor work, above 1 for a refrigerator and exactly one more for the same machine used as a heat pump
D.cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work
2. Which term means: "ratio of refrigerating effect to compressor work, above 1 for a refrigerator and exactly one more for the same machine used as a heat pump"?
A.Coefficient of performance — refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
B.Coefficient of performance — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
C.Coefficient of performance — ratio of refrigerating effect to compressor work, above 1 for a refrigerator and exactly one more for the same machine used as a heat pump
D.Coefficient of performance — cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work
A.cooling rate of 3.517 kW (211 kJ/min), the heat needed to melt one US ton of ice in 24 hours
B.fraction of air that passes through a cooling coil unchanged, lower for deeper coils with more rows and fins per inch
C.two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
D.refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
A.Ton of refrigeration — refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
B.Ton of refrigeration — cooling rate of 3.517 kW (211 kJ/min), the heat needed to melt one US ton of ice in 24 hours
C.Ton of refrigeration — two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
D.Ton of refrigeration — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
A.Wet bulb temperature — refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
B.Wet bulb temperature — ratio of sensible to total cooling load, which fixes the slope of the room process line on the psychrometric chart
C.Wet bulb temperature — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
D.Wet bulb temperature — two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
A.refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
B.two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
C.ratio of refrigerating effect to compressor work, above 1 for a refrigerator and exactly one more for the same machine used as a heat pump
D.cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work
11. Which term means: "cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work"?
A.Subcooling — refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
B.Subcooling — cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work
C.Subcooling — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
D.Subcooling — cooling rate of 3.517 kW (211 kJ/min), the heat needed to melt one US ton of ice in 24 hours
A.ratio of sensible to total cooling load, which fixes the slope of the room process line on the psychrometric chart
B.fraction of air that passes through a cooling coil unchanged, lower for deeper coils with more rows and fins per inch
C.two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
D.refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
14. Which term means: "refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve"?
A.Evaporator superheat — cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work
B.Evaporator superheat — refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
C.Evaporator superheat — fraction of air that passes through a cooling coil unchanged, lower for deeper coils with more rows and fins per inch
D.Evaporator superheat — two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
A.Sensible heat factor — ratio of sensible to total cooling load, which fixes the slope of the room process line on the psychrometric chart
B.Sensible heat factor — refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
C.Sensible heat factor — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
D.Sensible heat factor — R-22 phase-out under the Montreal Protocol and HFC reduction under the Kigali Amendment are driving Indian ACs to R-32 and R-290
A.refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
B.two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
C.reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
D.fraction of air that passes through a cooling coil unchanged, lower for deeper coils with more rows and fins per inch
A.R-22 phase-out under the Montreal Protocol and HFC reduction under the Kigali Amendment are driving Indian ACs to R-32 and R-290
B.refrigerant leaving the evaporator a few degrees above saturation so no liquid enters the compressor, set by the thermostatic expansion valve
C.reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
D.two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
23. Which term means: "R-22 phase-out under the Montreal Protocol and HFC reduction under the Kigali Amendment are driving Indian ACs to R-32 and R-290"?
A.Refrigerant phase-down — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
B.Refrigerant phase-down — R-22 phase-out under the Montreal Protocol and HFC reduction under the Kigali Amendment are driving Indian ACs to R-32 and R-290
C.Refrigerant phase-down — ratio of refrigerating effect to compressor work, above 1 for a refrigerator and exactly one more for the same machine used as a heat pump
D.Refrigerant phase-down — cooling liquid refrigerant below its saturation temperature before expansion, increasing refrigerating effect without extra compressor work
A.reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
B.fraction of air that passes through a cooling coil unchanged, lower for deeper coils with more rows and fins per inch
C.two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
D.R-22 phase-out under the Montreal Protocol and HFC reduction under the Kigali Amendment are driving Indian ACs to R-32 and R-290
26. Which term means: "two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio"?
A.Cascade refrigeration — ratio of sensible to total cooling load, which fixes the slope of the room process line on the psychrometric chart
B.Cascade refrigeration — reading of a thermometer whose bulb is covered by a wet wick in moving air, approaching dry bulb as the air nears saturation
C.Cascade refrigeration — two cycles with different refrigerants coupled through a heat exchanger to reach −50 °C and below where one refrigerant would need an excessive pressure ratio
D.Cascade refrigeration — ratio of refrigerating effect to compressor work, above 1 for a refrigerator and exactly one more for the same machine used as a heat pump
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