1. The difference between low-temperature cascade condenser temperature and high-temperature cascade evaporator temperature is called temperature ______
a) subtraction
b) overview
c) overlap
d) gradient
Explanation: Temperature overlap is the difference between low-temperature cascade condenser temperature and high-temperature cascade evaporator temperature. Temperature overlap is a crucial phenomenon to attain higher C.O.P. because it shows the heat transfer in the system.
2. What is Intermediate temperature?
a) Temperature overlap is zero
b) Temperature overlap is infinity
c) The temperature of the low-temperature cascade system
d) The temperature of the high-temperature cascade system
Explanation: Intermediate temperature is achieved when the temperature overlap is zero i.e., the difference between low-temperature cascade condenser temperature and high-temperature cascade evaporator temperature is zero. Intermediate temperature indicates that both temperatures are equal. Intermediate temperature affects the heat transfer in the system.
3. The performance of a refrigerant reciprocating compressor is not measured in terms of its ______________
a) refrigerating capacity
b) brake power per tonne of refrigeration
c) total brake power
d) horse power
Explanation: The performance of a refrigerant reciprocating compressor is not measured in terms of its refrigerating capacity, brake power per tonne of refrigeration and total brake power.
4. Which one of the following is not an important parameter in the design of a refrigerant reciprocating compressor?
a) Evaporator temperature
b) Condenser temperature
c) Suction temperature
d) Compressor temperature
Explanation: The important parameters in the design of a refrigerant reciprocating compressor are the evaporator or suction temperature and condenser temperatures.
5. The refrigeration capacity decreases with the decrease in the evaporator or suction temperature.
a) True
b) False
Explanation:
The refrigeration capacity decreases with the decrease in the evaporator or suction temperature. It is due to the fact that at low suction temperature, the vaporising pressure is low and therefore the density of suction vapor entering the compressor is low. Hence the mass of refrigerant circulated through the compressor per unit time decreases with the decrease in suction temperature for a given displacement.
6. The effect of suction temperature on the compressor B.P. per tonne of refrigeration is?
a) Compressor B.P. per tonne of refrigeration decreases with the increase in suction temperature
b) Compressor B.P. per tonne of refrigeration increases with the increase in suction temperature
c) Compressor B.P. per tonne of refrigeration remains the same with any change in suction temperature
d) Compressor B.P. per tonne of refrigeration decreases with the decrease in suction temperature
Explanation:
The effect of suction temperature on the compressor B.P. per tonne of refrigeration is that the compressor B.P. per tonne of refrigeration decreases with the increase in suction temperature, when the condenser temperature remains the same.
7. The effect of suction temperature on the total B.P. is?
a) To increase the B.P. with the decrease of suction temperature
b) To decrease the B.P. with the decrease of suction temperature
c) That the total B.P. remains unaffected by the changes in suction temperature
d) Can’t say only from the suction temperature
Explanation:
The total B.P. of the compressor is dependent on the work of compression and the mass of refrigerant circulated per minute. Hence the effect of suction temperature on the total B.P. is to increase the B.P. with the decrease of suction temperature.
8. What is the effect of condenser temperature on compressor refrigerating capacity?.
a) Increase in temperature decreases the refrigeration capacity
b) Decrease in temperature decreases the refrigeration capacity
c) Does not affect the capacity of refrigeration
d) Increase in temperature increases the refrigeration capacity
Explanation:
The effect of condenser temperature on compressor refrigerating capacity is to decreases the refrigeration capacity by increasing the condenser temperature.
9. What is the effect of condenser temperature on B.P. per tonne of refrigeration?
a) Increase in temperature decreases the B.P.
b) Decrease in temperature increases the B.P.
c) Does not affect the B.P
d) Increase in temperature increases the B.P.
Explanation:
The effect of condenser temperature on B.P. per tonne of refrigeration is to increase the B.P. by increasing the condenser temperature.
10. What is the effect of condenser temperature on total B.P.?
a) Increase in temperature decreases the total B.P.
b) Decrease in temperature increases the total B.P.
c) Does not affect the total B.P.
d) Increase in temperature increases the total B.P.
Explanation:
The effect of condenser temperature on the total B.P. is to increase the total B.P. by increasing the condenser temperature.