Refrigeration and Air Conditioning Questions and Answers Part-9

1. A vapor compression refrigeration system is an improved type of air refrigeration system in which a suitable working substance, termed as refrigerant is used.
a) True
b) False

Answer: a
Explanation: A vapor compression refrigeration system is an improved type of air refrigeration system in which a suitable working substance, termed as refrigerant is used. Refrigerants such as ammonia, CO2 and Sulphur dioxide etc. are used as refrigerants in a vapor compression refrigeration system

2. The vapor compression refrigeration system is similar to a ________
a) latent heat pump
b) latent heat engine
c) generator
d) evaporator

Answer: a
Explanation: The vapor compression refrigeration system is a latent heat pump, as it pumps its latent heat from the brine and delivers it to the cooler.

3 The first vapor compression refrigeration system was developed by ________.
a) L. G. Hamilton
b) Jacob Perkins
c) Stephen Rossi
d) Lenard Sandwik

Answer: b
Explanation: The first vapor compression refrigeration system was developed in 1834 by Jacob Perkins using hand operations.

4. The COP of vapor compression refrigeration compared to simple air refrigeration system is _______
a) low
b) high
c) same
d) can’t say

Answer: b
Explanation: COP of vapor compression refrigeration compared to simple air refrigeration system is high due to the use of refrigerant and as it can be employed over large range of temperatures

5. Which of the following is not an advantage of vapor compression refrigeration system over air refrigeration system
a) Smaller size for a given capacity of refrigeration
b) It has less running cost
c) It can be employed over wide range of temperature
d) There is no problem of leakage in vapor compression refrigeration system

Answer: d
Explanation: In vapor compression refrigeration system the prevention of leakage of the refrigerant is a major problem. The advantages of it are smaller size for a given capacity of refrigeration, it has less running cost and it can be employed over wide range of temperature

6. The low pressure and temperature vapor refrigerant enters the ______ of the vapor compression system.
a) compressor
b) condenser
c) receiver
d) evaporator

Answer: a
Explanation: In the compressor the low pressure and temperature vapor refrigerant from the evaporator is drawn through the suction valve, where it is compressed to high pressure and temperature.

7. The high pressure and temperature vapor refrigerant enters the ______ of the vapor compression system.
a) compressor
b) condenser
c) receiver
d) evaporator

Answer: b
Explanation: In the condenser the high pressure and temperature vapor refrigerant from the compressor is condensed, during which the refrigerant gives up its latent heat.

8. In any compression refrigeration system there are how many pressure conditions?
a) 1
b) 2
c) 3
d) 4

Answer: b
Explanation: In any compression refrigeration system there are 2 pressure conditions, namely high pressure and low pressure side.

9. Which of the following is not an advantage of vapor compression cycle over reversed Carnot cycle?
a) It’ COP and refrigeration effect can’t be increased
b) Use of expansion valve reduces the size and cost of plant
c) It is a practical cycle on which plant can be built
d) Wet compression of Carnot cycle is avoided

Answer: a
Explanation: It’ COP and refrigeration effect can be increased by use of superheated vapor at entry of compressor. The advantages are use of expansion valve reduces the size and cost of plant, it is a practical cycle on which plant can be built and wet compression of Carnot cycle is avoided

10. The pipe line emanating from compressor up to the condenser is called ________
a) suction line
b) pipe line
c) liquid line
d) delivery line

Answer: d
Explanation: The pipe line emanating from compressor up to the condenser is called delivery line or discharge line or hot gas line. Whereas suction line is the low pressure vapor line from the exit end evaporator leading to the compressor suction side and liquid line carries the liquid from receiver to the control valve.