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Mechanical Engineering :: Refrigeration and Air Conditioning

  1. Superheating in a refrigeration cycle

  2. A.

     Increases C.O.P

    B.

     Decreases C.O.P

    C.

     C.O.P remains unaltered

    D.

     Other factors decide C.O.P


  3. Hydrogen is used in Electrolux refrigeration system so as to _________ the rate of evaporation of the liquid ammonia passing through the evaporator.

  4. A.

     Equalize

    B.

     Reduce

    C.

     Increase

    D.

     None of these


  5. The dehumidification process, on the psychrometric chart, is shown by

  6. A.

     Horizontal line

    B.

     Vertical line

    C.

     Inclined line

    D.

     Curved line


  7. The process, generally used in winter air-conditioning to warm and humidity the air, is called

  8. A.

     Humidification

    B.

     Dehumidification

    C.

     Heating and humidification

    D.

     Cooling and dehumidification


  9. The process, generally used in summer air conditioning to cool and dehumidify the air, is called

  10. A.

     Humidification

    B.

     Dehumidification

    C.

     Heating and humidification

    D.

     Cooling and dehumidification


  11. The temperature of air recorded by a thermometer, when it is not affected by the moisture present in the air, is called

  12. A.

     Wet bulb temperature

    B.

     Dry bulb temperature

    C.

     Dew point temperature

    D.

     None of these


  13. The temperature of air recorded by a thermometer, when its bulb is surrounded by a wet cloth exposed to the air, is called

  14. A.

     Wet bulb temperature

    B.

     Dry bulb temperature

    C.

     Dew point temperature

    D.

     None of these


  15. The thermostatic expansion valve operates on the changes in the

  16. A.

     Degree of superheat at exit from the evaporator

    B.

     Temperature of the evaporator

    C.

     Pressure in the evaporator

    D.

     None of the above


  17. A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be

  18. A.

     1/4

    B.

     1/3

    C.

     3

    D.

     4


  19. A standard ice point temperature corresponds to the temperature of

  20. A.

     Water at 0°C

    B.

     Ice at 4°C

    C.

     Solid and dry ice

    D.

     Mixture of ice and water under equilibrium conditions