Book 2: 4-15 - "Refrigeration Theory" Flashcards
One tonne of refrigeration is equal to the equivalent of the heat needed to:
Select one:
A. Melt 1 tonne (1000 kg) of ice at a temperature of 0°C in 24 hours
B. Melt 1 tonne (1000 kg) of ice at a temperature of 100°C in 24 hours
C. Melt 1 tonne (1000 kg) of ice at a temperature of 10°C in 24 hours
D. Melt 1 tonne (1000 kg) of ice at a temperature of 0°C in 12 hours
E. Melt ½ tonne (500 kg) of ice at a temperature of 0°C in 24 hours
A. Melt 1 tonne (1000 kg) of ice at a temperature of 0°C in 24 hours
The compression ratio is calculated by dividing the:
Select one:
A. Absolute discharge pressure by the suction gauge pressure
B. Absolute suction pressure by the absolute discharge pressure
C. Discharge gauge pressure by the absolute suction pressure
D. Discharge gauge pressure by the Suction gauge pressure
E. Absolute discharge pressure by the absolute suction pressure
E. Absolute discharge pressure by the absolute suction pressure
How many tonnes of refrigeration would be accomplished if 251 244 kJ were removed in one hour?
Select one:
A. 12
B. 18
C. 16
D. 24
E. 20
B. 18
The high pressure in the condenser is maintained by the:
Select one:
A. Chiller
B. Evaporator
C. Compressor
D. Expansion valve
E. Receiver
C. Compressor
The low pressure in the evaporator is maintained by the:
Select one:
A. Chiller
B. Expansion valve
C. Compressor
D. Receiver
E. Condenser
C. Compressor
The control valve regulates the flow of liquid refrigerant into the:
Select one:
A. Evaporator
B. Receiver
C. Compressor
D. Expansion valve
E. Condenser
A. Evaporator
The boiling point of water is 100°C (212°F) when atmospheric pressure is 101.325 kPa (14.7 psi) and is also known as the:
Select one:
A. Saturation temperature
B. Vapour pressure
C. Enthalpy temperature
D. Vapour temperature
E. Condensation temperature
A. Saturation temperature
Refrigeration is defined as the thermodynamic process of:
Select one:
A. Lowering the temperature of a substance below the pressure of its surroundings and maintaining this substance at the lower pressure
B. Lowering the pressure of a substance below the temperature of its surroundings and maintaining this substance at the lower temperature
C. Lowering the temperature of a substance below the temperature of its surroundings and maintaining this substance at the lower temperature
D. Lowering the temperature of a substance below the temperature of its surroundings
E. Lowering the pressure of a substance below the pressure of its surroundings and maintaining this substance at the lower pressure
C. Lowering the temperature of a substance below the temperature of its surroundings and maintaining this substance at the lower temperature
The liquid refrigerant Freon-12, subjected to atmospheric pressure (100.4 kPa abs, 14.56 psi), boils at:
Select one:
A. -28°C (-18.4°F)
B. -38°C (-36.4°F)
C. -30°C (-22°F)
D. -33°C (-27.4°F)
E. -25°C (-13°F)
C. -30°C (-22°F)
The refrigeration process involves the transfer of heat from the substance to be cooled to a lower temperature substance called the:
Select one:
A. Refrigerant
B. Condensate
C. Regenerant
D. Evaporation
E. Refraction
A. Refrigerant
The loss of heat from a substance will cause its temperature to drop, the heat removed from the substance is:
Select one:
A. Sensible temperature
B. Enthalpy heat
C. Sensible heat
D. Latent temperature
E. Latent heat
C. Sensible heat
The boiling point of a liquid is raised by _____.
Select one:
A. Decreasing the pressure on the refrigerant
B. Increasing the size of the expansion valve
C. Increasing the temperature of the refrigerant
D. Increasing the pressure on the refrigerant
E. Increasing the strength of the refrigerant
D. Increasing the pressure on the refrigerant
The heat transfer process that ice undergoes in an ice box is _____.
Select one:
A. Sensible heat gain
B. Superheating
C. Latent heat loss
D. Sub-cooling
E. Latent heat gain
E. Latent heat gain
The coefficient of performance is the ratio of the amount of heat absorbed from the refrigerated medium by the __________ to the amount of __________________:
Select one:
A. Evaporator; energy used in the condenser
B. Condenser; energy released in the evaporator
C. Condenser; energy used to drive the compressor
D. Evaporator; energy used to drive the compressor
E. Compressor; energy used to drive the evaporator
D. Evaporator; energy used to drive the compressor
After leaving the compressor as a high-pressure vapour, the refrigerant can be exposed to air or water temperatures in a heat exchanger, called a:
Select one:
A. Chiller
B. Condenser
C. Evaporator
D. Receiver
E. Cooler
B. Condenser
