# Refrigeration and Air conditioning

Refrigeration and Air conditioning
Question:-
Option (A)
1/4
Option (B)
1/3
Option (C)
3
Option (D)
4
Correct Option:
C
Question Solution:

[COP]referi = (Desired effect/Work required)
Qabs+W= 120 kW
Qabs = 120 –W = 120-30 = 90W
\ COP = (90/30)=3
COP = 3
Question:-
Option (A)
Both A and R are individually true and R is the correct explanation of A
Option (B)
Both A and R are true but R is not the correct explanation A
Option (C)
A is true but R is false
Option (D)
A is false but R is true
Correct Option:
A
Question Solution:
At steady sate, the electrical energy W supplied to an electrical heater is dissipated to as heat to the space but when supplied to a heat dissipates Q1 (>W) giving a terminal advantage
Question:-
Option (A)
Both A and R are individually true and R is the correct explanation of A
Option (B)
Both A and R are true but R is not the correct explanation A
Option (C)
A is true but R is false
Option (D)
A is false but R is true
Correct Option:
B
Question Solution:
In vapour compression refrigeration the expansion cylinder system of expanding the liquid refrigerant is quit complicated and liquid refrigerant is quite complicated and involves greater initial cost. Therefore its use is not justified for small gain in cooling capacity. Moreover, the flow rate of the refrigerant can be controlled with throttle valve which is not possible in case of expansion cylinder which has a fixed cylinder volume
Question:-
Option (A)
More then dew point temperature
Option (B)
Same as dew point temperature
Option (C)
Less then dew point temperature
Option (D)
Equal to ambient temperature
Correct Option:
B
Question Solution:
Dew point temperature is the temperature at which first droplet of water comes out this is the case at 100% humidity line

Question:-
Option (A)
Dry bulb temperature is very close to the wet bulb temperature
Option (B)
Dry bulb temperature is high and relative humidity is high
Option (C)
Dry bulb temperature is low and relative humidity is high
Option (D)
Dry bulb temperature is high and the relative is low
Correct Option:
D
Question Solution:
Evaporative air-cooler used effectively when dry-bulb temperature is high and the relative humidity is low
The evaporative cooling is only successful in those area where reasonable low wet bulb (31°C and below) occurs simultaneously with dry bulb temperature (35°C above)
Question:-
Option (A)
Low unit weight per tone of refrigeration
Option (B)
High heat transfer rate
Option (C)
Lower temperature at high-altitudes
Option (D)
Higher coefficient of performance
Correct Option:
A
Question Solution:
In aircraft, air refrigeration, it is commonly used because of low unit weight per tone of refrigeration, it is becoming obsolete because of their low coefficient of performance and high power requirements