250+ MCQs on Two/Multi Stage Compression with Water Intercooling, Liquid Subcooling and Flash Chamber

Refrigeration Questions and Answers for Entrance exams on “Two/Multi Stage Compression with Water Intercooling, Liquid Subcooling and Flash Chamber ”.

1. Why is multi-stage or compound VCR with water intercooler, liquid sub-cooler, and the flash chamber used?
a) To improve C.O.P.
b) To decrease the refrigeration effect
c) To increase work
d) To increase leakage loss

Answer: a
Clarification: By de-superheating or intercooling the refrigerant before the second stage compression but not till the saturated vapor line, can decrease the total work required. By using the liquid sub-cooler, subcooling is done, and an increase in the refrigeration effect is achieved. Use of flash chamber ensures the saturated vapor form of refrigerant being entered into the second stage, which also helps reduce the work. So, the increase in R.E. and decrease in work improves the C.O.P. of the system.

2. What is the purpose of using intercooler?
a) To increase the cost of the compressor
b) To cool the superheated refrigerant
c) To re-heat superheated refrigerant
d) To reduce the volumetric efficiency

Answer: b
Clarification: Intercooler is used to cool the superheated refrigerant by some amount but in this case, not till the saturated vapor line. The superheated refrigerant leaving the first compressor is cooled by suitable method before entering the second compressor. This type of cooling is known as intercooling.

3. What is the purpose of using liquid sub-cooler?
a) To increase the cost of the compressor
b) To reduce the volumetric efficiency
c) To re-heat superheated refrigerant
d) To increase the refrigeration effect

Answer: d
Clarification: Liquid sub-cooler is used to sub-cool the liquid refrigerant coming from the condenser beyond the saturated liquid line. Sub-cooling results in an increase in refrigeration effect and thus increasing the C.O.P.

4. What is the purpose of using a flash chamber?
a) To increase pressure
b) To decrease pressure
c) To separate vapor and liquid refrigerant
d) To evaporate refrigerant partially

Answer: c
Clarification: Flash chamber is used to separate vapor and liquid refrigerant. It is an insulated container and separates both forms by using the centrifugal effect.

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