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Mechanical Engineering :: Heat Transfer,Refrigeration and Air Conditioning

  1. The centrifugal compressors are generally used for refrigerants that require

  2. A.
    small displacements and low condensing pressures
    B.
    large displacements and high condensing pressures
    C.
    small displacements and high condensing pressures
    D.
    large displacements and low condensing pressures

  3. The water, alcohol and ammonia have same refrigerating effect at different altitudes.

  4. A.
    Yes
    B.
    No

  5. The automobile radiator is a heat exchanger of

  6. A.
    parallel flow type
    B.
    counter flow type
    C.
    cross flow type
    D.
    regenerator type

  7. In mechanical refrigeration system, the refrigerant occurs as liquid between condenser and expansion valve.

  8. A.
    True
    B.
    False

  9. A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be

  10. A.
    1 kW
    B.
    2 kW
    C.
    3 kW
    D.
    4 kW

  11. The curved lines on a psychrometric chart indicates

  12. A.
    dry bulb temperature
    B.
    wet bulb temperature
    C.
    dew point temperature
    D.
    relative humidity

  13. During humidification process, __________ increases.

  14. A.
    wet bulb temperature
    B.
    relative humidity
    C.
    dry bulb temperature
    D.
    specific humidity

  15. A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be

  16. A.
    lack of cooling water
    B.
    water temperature being high
    C.
    dirty condenser surface
    D.
    all of these

  17. The counter-current flow heat exchanger can transfer __________ heat than parallel flow heat exchanger.

  18. A.
    less
    B.
    more

  19. The freon group of refrigerants are

  20. A.
    halo-carbon refrigerants
    B.
    azeotrope refrigerants
    C.
    inorganic refrigerants
    D.
    hydro-carbon refrigerants