Refrigeration and Air Conditioning – Questions and Answers

Refrigeration and Air Conditioning – Questions and Answers

1-The minimum temperature to which air can be cooled under ideal conditions in evaporative cooling is

(A) Dew point temperature of the inlet air

(B) Wet bulb temperature of the inlet air

(C) Dry bulb temperature of the inlet air

(D) All of the above

 

2-For summer air conditioning in coastal regions, the psychometric process employed is 

(A) Cooling and humidification

(B) Cooling and dehumidification

(C) Sensible cooling

(D) Sensible heating

 

3-In psychometric during a sensible cooling, the dew point temperature

(A) Decreases

(B) Increases

(C) May increase and decrease

(D) remains constant

 

4-It is desirable for a good refrigerant to have

(A) High critical temperature

(B) Low critical temperature

(C) High freezing point

(D) High melting point

 

5-Which of the following is not an ozone friendly refrigerant?

(A) Freon-12

(B) Ammonia

(C) Air

(D) Carbon dioxide

 

6-In aqua ammonia absorption refrigeration system the refrigerant is

(A) Water

(B) Aqua

(C) Ammonia

(D) Air

 

7-In vapour compression refrigeration system oil separator is placed between

(A) Compressor and Condenser

(B) Condenser and throttling valve

(C) Throttling valve and evaporator

(D) Evaporator and Compressor

 

8-In vapour Compression refrigeration system, heat is rejected by the refrigerant in

(A) Compressor

(B) Condenser

(C) Throttle valve

(D) Evaporator

 

9-Air refrigerator works on

(A) Carnot cycle

(B) Rankine cycle

(C) Brayton cycle

(D) Bell Coleman cycle

 

10-Which of the following compound is not a refrigerant?

(A) Ammonia

(B) Carbon dioxide

(C) Carbon monoxide

(D) Sulphur dioxide

 

11-The wet bulb depression is zero when relative humidity equals

(A) 1.0

(B) 0.5

(C) 0.75

(D) zero

 

12-The following refrigerant is used for refrigeration purposes in passenger aircraft.

(A) Freon-12

(B) Carbon dioxide

(C) Air

(D) Sodium chloride

 

13-One Ton refrigeration is equivalent to

(A) 1 kW

(B) 2.5 kW

(C) 3.5 kW

(D) 5kW

 

14-The presence of which of the following units in a vapour compression system is adversely affected by the presence of moisture?

(A) Condenser

(B) Expansion valve

(C) Evaporator

(D) Compressor

 

15-The ratio of high temperature to low temperature for reversed Carnot refrigeration is 1.25. The COP will be

(A) 2

(B) 3

(C) 4

(D) 5

 

16-The colour of flame during halide torch test for refrigerant leaks will change to

(A) Grey

(B) Blue to bright green

(C) Black

(D) Pink or red

 

17-Bell Coleman cycle is a reversed

(A) Rankine cycle

(B) Otto cycle

(C) Joule cycle

(D) Carnot cycle

 

17-In in ideal refrigeration cycle, the condenser and evaporator temperature are 27°C and -13°C respectively. The COP of cycle is.

(A) 6.5

(B) 7.5

(C) 10.5

(D) 15

 

18-In an absorption refrigeration cycle, the compressor of the vapour compression refrigeration cycle is replaced by

(A) Liquid pump

(B) Generator

(C) Absorber and generator

(D) Absorber, liquid pump and generator

 

19-In a vapour absorption refrigerator, heat is rejected in

(A) Condenser only

(B) Condenser and absorber

(C) Generator only

(D) Absorber only

 

20-The atmosphere air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The by-pass factor of the heating coil is

(A) 0.376

(B) 0.4

(C) 0.6

(D) 0.67

 

ANSWERS:

1-(B), 2-(B), 3-(D), 4-(A), 5-(A), 6-(C), 7-(A), 8-(B), 9-(D), 10-(C), 11-(A), 12-(C), 13-(C), 14-(B), 15-(C), 16-(B), 17-(A), 18-(C), 19-(B), 20-(C)