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Mechanical Engineering :: Heat Transfer,Refrigeration and Air Conditioning

  1. The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)

  2. A.
    25°C DBT and 100% RH
    B.
    20°C DBT and 80% RH
    C.
    22°C DBT and 60% RH
    D.
    25°C DBT and 40% RH

  3. The dry bulb temperature lines, on the psychrometric chart are

  4. A.
    vertical and uniformly spaced
    B.
    horizontal and uniformly spaced
    C.
    horizontal and non-uniformly spaced
    D.
    curved lines

  5. The pressure at the outlet of a refrigerant compressor is called

  6. A.
    suction pressure
    B.
    discharge pressure
    C.
    critical pressure
    D.
    back pressure

  7. A simple air cooling system is good for __________ flight speeds.

  8. A.
    low
    B.
    high

  9. The highest temperature during the cycle in a vapour compression system occurs after evaporation.

  10. A.
    True
    B.
    False

  11. In a psychrometric chart, dew point temperature lines are horizontal and non-uniformly spaced.

  12. A.
    Correct
    B.
    Incorrect

  13. If the evaporator temperature is kept constant, the coefficient of performance of a refrigeration cycle __________ with the increase in condenser temperature.

  14. A.
    increases
    B.
    decreases

  15. The by-pass factor, in case of sensible cooling of air, is given by (where td1 = Dry bulb temperature of air entering the cooling coil, td2 = Dry bulb temperature of air leaving the cooling coil, and td3 = Dry bulb temperature of the cooling coil)


  16. The evaporator used in house-hold refrigerators is

  17. A.
    frosting evaporator
    B.
    non-frosting evaporator
    C.
    defrosting evaporator
    D.
    none of these

  18. The drier in a refrigeration system removes moisture in the system.

  19. A.
    Correct
    B.
    Incorrect