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Refrigeration and Air Conditioning Practice Test: Simple Vapour Compression Refrigeration Systems
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Simple Vapour Compression Refrigeration Systems topics include: Simple VCR system mechanism, theoretical VCR with dry saturated vapour and superheated vapour after compression, actual VCR cycle, VCR system various parameters effect and pressure – enthalpy chart. A vapor compression refrigeration system (VCRS) is a closed system that uses mechanical energy to cool the surrounding air. VCRS systems are made up of four main components: Compressor: A mechanical device that increases the pressure of gaseous refrigerants by decreasing their volume Condenser: Changes the phase of the refrigerant... Show more
Refrigeration and Air Conditioning Practice Test: Simple Vapour Compression Refrigeration Systems
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25 Questions

1. The COP of vapor compression refrigeration compared to simple air refrigeration system is ________
2. The ultimate effect of undercooling is to increase the value of COP under same set of conditions.
3. What is the use of accumulator or pre-cooler in VCR system?
4. In a vapor compression refrigeration system, the coefficient of performance is observed as 10. If the enthalpy after compression is 1368.28 kJ/kg and after condensation is 598.58 kJ/kg. If the system works on 50% of the C.O.P., then what is the value of enthalpy after evaporation?
5. Effect of high side pressure or discharge pressure or condenser pressure is to reduce the COP of the cycle.
6. Which of the following is not the difference between theoretical and actual VCR cycle?
7. What is the effect of a decrease in suction pressure on C.O.P.?
8. One of the assumptions of the vapor compression cycle is that all of the processes are reversible.
9. After which process during the VCR cycle, the highest temperature is achieved?
10. Which one of the following is not effect of change in suction pressure?
11. Find out the value of C.O.P. for the given values of enthalpies.
h1 = 1126.25 kJ/kg
h4 = 250.25 kJ/kg
W = 120 kJ/kg
12. If a process 1 – 2 undergoes a throttling. Which of the following represents the process 1 – 2?
13. The COP of the cycle may increase or decrease or remain unchanged depending upon the range of pressure and the degree of superheating.
14. What is the effect of an increase in discharge pressure on C.O.P.?
15. What is the effect of using a flash chamber in VCR system?
16. The coefficient of performance of a vapour compression refrigeration system is quite high as compared to the air refrigeration system.
17. The net effect of superheating is to have ________ COP.
18. The low pressure and temperature vapor refrigerant enters the ______ of the vapor compression system.
19. In any compression refrigeration system there are how many pressure conditions?
20. What effect does the under cooling process have on piston displacement of the compressor?
21. The vapor compression refrigeration system is similar to a ________
22. What is the value of C.O.P. in the VCR with a flash chamber?
23. The difference between the saturation temperature T3 of liquid refrigerant at pressure p3 = p2 and the actual temperature of liquid refrigerant T3′ is called?
24. Which of these is not an effect of superheat in suction vapour?
25. Which of the following factor of the actual VCR affects severely the coefficient of performance?