Heat Transfer, Refrigeration and Air Conditioning problems
- 1. The C.O.P. of a refrigerator working on a reversed Carnot cycle is (where T1 = Lowest absolute temperature, and T2 = Highest absolute temperature)
Options- A.
- B.
- C.
- D.
Discuss
Correct Answer:
- 2. In a domestic refrigerator, a capillary tube controls the flow of refrigerant from the
Options- A. expansion valve to the evaporator
- B. evaporator to the thermostat
- C. condenser to the expansion valve
- D. condenser to the evaporator Discuss
Correct Answer: condenser to the evaporator
- 3. The process, generally used in summer air conditioning to cool and dehumidify the air, is called
Options- A. humidification
- B. dehumidification
- C. heating and humidification
- D. cooling and dehumidification Discuss
Correct Answer: cooling and dehumidification
- 4. The capillary tube, as an expansion device, is used in
Options- A. domestic refrigerators
- B. water coolers
- C. room air conditioners
- D. all of these Discuss
Correct Answer: all of these
- 5. Which of the following statement is wrong?
Options- A. The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.
- B. In vapour compression cycle, the useful part of the heat transfer is at the condenser.
- C. In ammonia-hydrogen (electolux) refrigerator, no compressor, pump or fan is required.
- D. The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance. Discuss
Correct Answer: The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance.
- 6. In which of the following refrigeration system, waste heat can be effectively used?
Options- A. Vapour compression cycle
- B. Vapour absorption cycle
- C. Air refrigeration cycle
- D. none of these Discuss
Correct Answer: Vapour absorption cycle
- 7. During heating and dehumidification process, dry bulb temperature
Options- A. remains constant
- B. increases
- C. decreases Discuss
Correct Answer: increases
- 8. In a pressure enthalpy chart, the space to the left of the saturated liquid line represents
Options- A. wet vapour region
- B. superheated vapour region
- C. sub-cooled liquid region
- D. none of these Discuss
Correct Answer: sub-cooled liquid region
- 9. The process of undercooling is generally brought about by
Options- A. circulating more quantity of cooling water through the condenser
- B. using water colder than the main circulating water
- C. employing a heat exchanger
- D. any one of the above Discuss
Correct Answer: any one of the above
- 10. R-12 has the __________ freezing point.
Options- A. lowest
- B. highest Discuss
Correct Answer: lowest
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