Home / Mechanical Engineering / Refrigeration and Air Conditioning :: section-1

Mechanical Engineering :: Refrigeration and Air Conditioning

  1. When the lower temperature of a refrigerating machine is fixed, then the coefficient of performance can be improved by

  2. A.

     Operating the machine at higher speeds

    B.

     Operating the machine at lower speeds

    C.

     Raising the higher temperature

    D.

     Lowering the higher temperature

    View Answer

    Workspace

    Discuss Discuss in Forum


  3. The evaporator changes the low pressure liquid refrigerant from the expansion valve into

  4. A.

     High pressure liquid refrigerant

    B.

     Low pressure liquid and vapour refrigerant

    C.

     Low pressure vapour refrigerant

    D.

     None of these

    View Answer

    Workspace

    Discuss Discuss in Forum


  5. The coefficient of performance is the ratio of the refrigerant effect to the

  6. A.

     Heat of compression

    B.

     Work done by compressor

    C.

     Enthalpy increase in compressor

    D.

     All of the above

    View Answer

    Workspace

    Discuss Discuss in Forum


  7. In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is

  8. A.

     Less than 2 kg

    B.

     More than or equal to 3.65 kg

    C.

     More than 10 kg

    D.

     There is no such consideration

    View Answer

    Workspace

    Discuss Discuss in Forum


  9. Pressure of water vapour is given by

  10. A.

     0.622 Pv/ (Pb - Pv)

    B.

     μ/[1 - (1 - μ) (Ps/Pb)]

    C.

     [Pv (Pb - Pd)]/ [Pd (Pb - Pv)]

    D.

     None of these

    View Answer

    Workspace

    Discuss Discuss in Forum


  11. In vapour compression cycle using NH₃ as refrigerant, initial charge is filled at

  12. A.

     Suction of compressor

    B.

     Delivery of compressor

    C.

     High pressure side close to receiver

    D.

     Low pressure side near receiver

    View Answer

    Workspace

    Discuss Discuss in Forum


  13. If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of -23°C, then the Carnot COP will be

  14. A.

     0.2

    B.

     1.2

    C.

     5

    D.

     6

    View Answer

    Workspace

    Discuss Discuss in Forum


  15. Vertical lines on pressure-enthalpy chart show constant

  16. A.

     Pressure lines

    B.

     Temperature lines

    C.

     Total heat lines

    D.

     Entropy lines

    View Answer

    Workspace

    Discuss Discuss in Forum


  17. A vapour absorption refrigerator uses _________ as a refrigerant.

  18. A.

     Water

    B.

     Ammonia

    C.

     Freon

    D.

     Aqua-ammonia

    View Answer

    Workspace

    Discuss Discuss in Forum


  19. Which of the following statement is correct for ammonia as a refrigerant?

  20. A.

     It is toxic to mucous membranes.

    B.

     It requires large displacement per TR compared to fluoro carbons.

    C.

     It reacts with copper and its alloys.

    D.

     All of these

    View Answer

    Workspace

    Discuss Discuss in Forum