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MCQ
84. For the same capacity of plant, the COP of the vapor absorption refrigeration system is--
lower than the COP of the vapour compression refrigeration system
higher than the COP of the vapour compression refrigeration system
same as the COP of the vapour compression refrigeration system
none of the above
86. The operating temperature of a cold storage is -4°C. The heat leakage from the surrounding is 30kW for the ambient temperature of 35°C. The actual COP of refrigeration plant used is one fourth that of ideal plant working between the same temperatures. The power required to drive the plant is-
1.86kW
7.44kW
3.72kW
21.74W
90. The COP of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant will-
increase
decrease
unpredictable
remain unaffected
91. The evolution of heat of solution takes place in ammonia absorption plant when--
ammonia vapour goes into solution
ammonia vapour is driven out of solution
lithium bromide mixes with ammonia
weak solution mixes with strong solution
95. The COP of a refrigeration cycle with increase in evaporatour temperature, keeping condenser temperature constant will-.
decrease
increase
remain unaffected
unpredictable
97. Reducing suction pressure in refrigeration cycle-.
lowers evaporation temperature
increases power required per ton of refrigeration
lowers compressor capacity because vapour is highter
reduces weight displaced by piston
all of the above
98. A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be-
1.33
3.33
2.33
4.33
100. The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of COP-
more
equally
less
unpredictable