250+ TOP MCQs on Simple Air Cooling System and Answers

Refrigeration Multiple Choice Questions on “Simple Air Cooling System”.

1. Which one of the following is not a component of a simple air cooling system?
a) Main compressor
b) Cooling fan
c) Heat exchanger
d) Generator
Answer: d
Clarification: The main components of simple air cooling system are the main compressor driven by the gas turbine, a cooling fan, heat exchanger and a cooling turbine.

2. For a simple air cooling system which one of the following is not a process of the cycle in T-S diagram?

a) Ramming process
b) Compression process
c) Heating process
d) Refrigeration process
Answer: c
Clarification: A simple air cooling system has 5 processes in T-S diagram namely ramming process, compression process, expansion process, refrigeration processes and cooling process.

3. The COP of simple air cooling system is given by?
T₆ = Inside temperature of cabin
T_5′ = Exit temperature of cooling turbine
T_3′ = Temperature at the exit of compressor
T_2′ = Stagnation temperature
a) COP = (frac{(T_6 – T_{5′})}{(T_3′ – T_{2′})})
b) COP = (frac{(T_6 + T_{5′})}{(T_3′ – T_{2′})})
c) COP = (frac{(T_6 + T_{5′})}{(T_3′ + T_{2′})})
d) COP = (frac{(T_6 – T_{5′})}{(T_3′ + T_{2′})})
Answer: a
Clarification: COP = Refrigeration effect produced i.e. (T₆ – T_5′) divided by Work done i.e. (T_3′ – T_2′).
Hence COP = (frac{(T_6 – T_{5′})}{(T_3′ – T_{2′})}).

4. The simple air cooling system is good for _____ flight speed.
a) low
b) high
c) moderate
d) any
Answer: a
Clarification: The simple air cooling system is good for low flight speed so as fan can maintain airflow over the air cooler, which is difficult for it while at high speeds.

5. What is the main difference between simple air cooling system and simple air evaporative cooling system?
a) Simple air evaporative cooling system has an evaporator
b) Simple air evaporative cooling system has two evaporators
c) Simple air evaporative cooling system has an extra compressor
d) Simple air evaporative cooling system has three evaporators
Answer: a
Clarification: The difference between the simple air cooling system and simple air evaporative cooling system is that it has an evaporator between the heat exchanger and the cooling turbine.

6. If cooling of 45 minutes or less is required, it may be advantageous to use evaporative cooling system.
a) True
b) False
Answer: a
Clarification: The evaporative cooling system provides an additional cooling effect through evaporation of refrigerants such as water etc. Hence if cooling of 45 minutes or less is required, it may be advantageous to use evaporative cooling system.

7. A simple evaporative air refrigeration system is used for an airplane to take 20 TR of refrigeration load (Q). The power required for the refrigerating system P is 746 KW. What is its COP?
a) 0.086
b) 0.094
c) 0.079
d) 0.099
Answer: b
Clarification: COP = (frac{(210×Q)}{(P×60)})
COP = (frac{(210×20)}{(746×60)})
= 0.094.