Test: Vapour Compression Systems, Refrigerants - 1 - Mechanical Engineering MCQ

Which one of the following is correct?

Environmental protection agencies advise against the use of chlorofluorocarbon refrigerants because these react with 

In a vapour compression refrigeration plant, the refrigerant leaves the evaporator at 195 kJ/kg and the condenser at 65 kJ/kg. For 1 kg/s of refrigerant, what is the refrigeration effect?

The enthalpies at the beginning of compression, at the end of compression and at the end of condensation are respectively 185 kJ/kg, 210 kJ/kg and 85 kJ/kg. The COP of the vapour compression refrigeration system is

The correct sequence of the given components of a vapour compression refrigerator is:

In conventional refrigerants what is the element responsible for ozone depletion?

Consider the following statements:

1. Practically all common refrigerants have approximately the same COP and power requirement.

2. Ammonia mixes freely with lubricating oil and this helps lubrication of compressors.

3. Dielectric strength of refrigerants is an important property in hermetically sealed compressor units.

4. Leakage of ammonia can be detected by' halide torch method.  Of these statements:  

Match List-I with List-II and select the correct answer

Consider the following statements:  In the case of a vapour compression machine, if the condensing temperature of the refrigerant is closer to the critical temperature, then there will be:  

1.Excessive power consumption  

2.High compres sion

3.Large volume flow  

Of these statements:  

Assertion (A): In vapour compression refrigeration system throttle valve is used and not expansion cylinder.

Reason (R): Throttling is a constant enthalpy process. 

Sub-cooling with regenerative heat exchanger is used in a refrigeration cycle. The enthalpies at condenser outlet and evaporator outlet are 78 and 182 kJ/kg respectively. The enthalpy at outlet of isentropic compressor is 230 kJ/kg and enthalpy of subcooled liquid is 68 kJ/kg. The COP of the cycle is:

Assertion ( A): I n a practical vapour compression refrigerator, the vapour should leave the evaporator with a definite amount of superheat.

Reason (R): It reduces the work done by the compressor. 

Selection of a refrigerant for a vapour – compression system depends on which among the following?

Oil separator is NOT required in refrigeration system if:  

Consider the following statements:

Moisture should be removed from refrigerants to avoid 

1. Compressor seal failure

2. Freezing at the expansion valve  

3. Restriction to refrigerant flow

4. Corrosion of steel parts 

Of these statements: 

Consider the following statements:

1.The work of compressor in vapour compression refrigeration system  increases with superheat of the suction vapour.  2.The work of compressor depends on the pressure difference rather than  the temperature difference of evaporator and condenser.  3.The coefficient of performance is within the range of 3 to 6 except at very  low temperature when it may be less than 1.  

Which of the statements given above are correct? 

In a vapour compression cycle, the refrigerant, immediately after expansion value is:

This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Vapor Compression Refrigeration Cycle-1”.