Refrigeration And Air Conditioning(Mechanical Engineering ) Questions and Answers

Question 1. Hydrogen is used in Electrolux refrigeration system so as to _________ the rate of evaporation of the liquid ammonia passing through the evaporator.
  1.    Equalize
  2.    Reduce
  3.    Increase
  4.    None of these
Explanation:-
Answer: Option C. -> Increase
Hydrogen is used in Electrolux refrigeration system so as to increase the rate of evaporation of the liquid ammonia passing through the evaporator.
Question 2. The dehumidification process, on the psychrometric chart, is shown by
  1.    Horizontal line
  2.    Vertical line
  3.    Inclined line
  4.    Curved line
Explanation:-
Answer: Option B. -> Vertical line
The dehumidification process, on the psychrometric chart, is shown by Vertical line
Question 3. Superheating in a refrigeration cycle
  1.    Increases C.O.P.
  2.    Decreases C.O.P.
  3.    C.O.P. remains unaltered
  4.    Other factors decide C.O.P.
Explanation:-
Answer: Option B. -> Decreases C.O.P.
Superheating in a refrigeration cycle decreases C.O.P.
Question 4. The process, generally used in winter air-conditioning to warm and humidity the air, is called
  1.    Humidification
  2.    Dehumidification
  3.    Heating and humidification
  4.    Cooling and dehumidification
Explanation:-
Answer: Option C. -> Heating and humidification
The process, generally used in winter air-conditioning to warm and humidity the air, is called Heating and humidification
Question 5. The process, generally used in summer air conditioning to cool and dehumidify the air, is called
  1.    Humidification
  2.    Dehumidification
  3.    Heating and humidification
  4.    Cooling and dehumidification
Explanation:-
Answer: Option D. -> Cooling and dehumidification
The process, generally used in summer air conditioning to cool and dehumidify the air, is called Cooling and dehumidification
Question 6. Highest pressure encountered in a refrigeration system should be
  1.    Critical pressure of refrigerant
  2.    Much below critical pressure
  3.    Much above critical pressure
  4.    Near critical pressure
Explanation:-
Answer: Option B. -> Much below critical pressure
Highest pressure encountered in a refrigeration system should be Much below critical pressure
Question 7. Which of the following cycles uses air as the refrigerant?
  1.    Ericson
  2.    Stirling
  3.    Carnot
  4.    Bell Coleman
Explanation:-
Answer: Option D. -> Bell Coleman
The Bell Coleman Cycle also called as the Joule or "reverse" Brayton cycle.
it is a refrigeration cycle where the working fluid is a gas that is compressed and expanded, but does not change phase.
Question 8. The heat rejection factor (HRF) is given by
  1.    1 + C.O.P.
  2.    1 - C.O.P.
  3.    $$1 + \frac{1}{{{\text{C}}{\text{.O}}{\text{.P}}{\text{.}}}}$$
  4.    $$1 - \frac{1}{{{\text{C}}{\text{.O}}{\text{.P}}{\text{.}}}}$$
Explanation:-
Answer: Option C. -> $$1 + \frac{1}{{{\text{C}}{\text{.O}}{\text{.P}}{\text{.}}}}$$
The heat rejection factor (HRF) is given by $$1 + \frac{1}{{{\text{C}}{\text{.O}}{\text{.P}}{\text{.}}}}$$
Question 9. In a vapour compression system, the condition of refrigerant before passing through the condenser is
  1.    Saturated liquid
  2.    Wet vapour
  3.    Dry saturated vapour
  4.    Superheated vapour
Explanation:-
Answer: Option D. -> Superheated vapour
In a vapour compression system, the condition of refrigerant before passing through the condenser is Superheated vapour
Question 10. In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is
  1.    Heated and dehumidified
  2.    Heated and humidified
  3.    Cooled and humidified
  4.    Cooled and dehumidified
Explanation:-
Answer: Option B. -> Heated and humidified
In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is Heated and humidified
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