This set of Refrigeration Multiple Choice Questions & Answers (MCQs) focuses on “Domestic Electrolux and Lithium Bromide Refrigeration System – 1”.
1. Which one of the refrigerant is not used in the domestic Electrolux?
a) Ammonia
b) Water
c) Hydrogen
d) Freon – 12
View Answer
Explanation: The ammonia is used as a refrigerant because it possesses most of the desirable properties. It is toxic, but due to the absence of moving parts, there is very little chance for leakage and the total amount used is also small. The hydrogen, being the lightest gas, is used to increase the rate of evaporation of the liquid ammonia passing through the evaporator.
2. What is water used for in the Domestic Electrolux?
a) Water is used to absorb hydrogen
b) Water is used to absorb ammonia
c) Water is used as a lubricant
d) Water is used to keep the inner surface clean
View Answer
Explanation: The function of water is used as a solvent as it has the ability to absorb ammonia readily. The hydrogen is also non – corrosive and insoluble in water.
3. The Domestic absorption type refrigerator was invented by?
a) Carl Munters
b) Baltzer Von Platan
c) Carl Munters and Baltzer Von Platan
d) Light Foot
View Answer
Explanation: The Domestic absorption type refrigerator was invented by two Swedish engineers, Carl Munters and Baltzer Von Platan, in 1925 while they were studying for their undergraduate course of Royal Institute of Technology in Stockholm. Whereas Light foot invented the Bell – Coleman cycle.
4. The Domestic Electrolux cannot be used for industrial purposes.
a) True
b) False
View Answer
Explanation: The Domestic Electrolux cannot be used for industrial purposes as the COP of the system is very low. The whole cycle is carried out entirely by the gravity flow of the refrigerant.
5. Find the COP of the domestic Electrolux system when the heat supplied in the generator (QG) is 1885 KJ/kg and the heat absorbed in the evaporator (Qe) is 1045 KJ/kg.
a) 0.4
b) 0.45
c) 0.55
d) 0.65
View Answer
Explanation: The COP of the domestic Electrolux system is the ratio of the heat absorbed by the evaporator and the heat supplied by the evaporator.
COP = \(\frac{1045}{1885}\) = 0.554.
6. Which of the refrigerant is used as a refrigerant in Lithium Bromide Absorption Refrigeration system?
a) Ammonia
b) Water
c) Hydrogen
d) Lithium Bromide
View Answer
Explanation: Water is used as a refrigerant in Lithium Bromide Absorption Refrigeration system whereas lithium bromide, which is highly hydroscopic salt, is used as an absorbent. Lithium Chromate is used a corrosion inhibitor.
7. In lithium bromide absorption refrigeration system it is not necessary to keep the refrigeration temperature above 0°C.
a) True
b) False
View Answer
Explanation: In lithium bromide absorption refrigeration system it is necessary to keep the refrigeration temperature above 0°C as it is the freezing point of water. Water is used as a refrigerant in the system.
8. Find the COP of the lithium bromide absorption system when the heat supplied in the generator (QG) is 1255 KJ/kg and the heat absorbed in the evaporator (Qe) is 955 KJ/kg.
a) 0.66
b) 0.75
c) 0.85
d) 0.76
View Answer
Explanation: The COP of the lithium bromide absorption refrigeration system is the ratio of the heat absorbed by the evaporator and the heat supplied by the evaporator.
COP = \(\frac{955}{1255}\) = 0.76.
9. Find the relative COP of the system whose maximum COP is 2.0 and the actual COP is 0.8.
a) 0.5
b) 0.4
c) 0.3
d) 0.6
View Answer
Explanation: The relative COP is the ratio of actual COP and the maximum COP of the system,
Relative COP = (Actual COP) / (Maximum COP)
= \(\frac{0.8}{2.0}\) = 0.4.
Sanfoundry Global Education & Learning Series – Refrigeration & Air Conditioning.
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