AIR REFRIGERATION SYSTEM
1. Reversed carnot cycle comprises
(a) two isentropic processes and
two adiabatic processes
(b) two isentropic
processes and two isothermal processes
(c) two isentropic processes and
two isobaric processes
(d) two isentropic processes and
two isochoric processes
2. Two Carnot Refrigerators are
employed, one for ice making and other for comfort cooling
(a) The COP of the refrigerator for
ice making is higher than that for other
(b) The COP of the refrigerator for
ice making is same as that for the other
(c) The COP of the
refrigerator for ice making is lower than that for other
(d) The COP of Carnot refrigerator
will depend on refrigerant used
3. A reversed Carnot cycle has a COP of 4. The ratio of higher temperature to lower temperature will be
(a) 1.25
(b) 1.5
(c) 2
(d) 2.5
4. Carnot refrigerator absorbs heat at -13° C and requires 1 kW for each 6.5 kW of heat absorbed, the COP and temperature of heat rejections respectively
(a) COP = 6.5, t = 27° C
(b) COP = 7.5, t = 27° C
(c) COP = 6.5, t = 30° C
(d) COP =
7.5, t = 37° C
5. The dense air refrigeration system as compared to open air refrigeration system for same range of temperatures using Bell- Colemann cycle requires.
(a) Same power/Ton of Refrigeration
(b) Lower power/Ton of
Refrigeration
(c) Higher power/Ton of
Refrigeration
(d) Unpredictable Results
6. The amount of heat absorbed by
the system at low temperature is
(a) COP
(b) refrigerating effect
(c) work done on the system
(d) refrigeration efficiency
7. No refrigerator using reversed
Carnot cycle has been constructed because
(a) it is less efficient
(b) it is uneconomical
(c) isentropic portions of cycle require low speeds where as isothermal portions require high speeds
(d) isentropic portions of cycle require high speeds where as isothermal portions require low speeds
8. A refrigeration cycle is
usually a
(a) open cycle
(b) closed cycle
(c) mixed cycle
(d) Hybrid cycle
9. Co-efficient of performance of a Reversed Carnot cycle refrigerator working between higher temperature T2 and lower temperature T1
(a) will increase with
increase in T1 keeping T2 fixed
(b) will decrease with increase in
T1 keeping T2 fixed
(c) will first increase with increase in T1 and then decrease with increase T1 keeping T2 fixed
(d) None of the above
10.Bell-Colemann cycle comprises
(a) two isentropic processes and
two adiabatic processes
(b) two isentropic processes and
two isothermal processes
(c) two isentropic
processes and two isobaric processes
(d) two isentropic processes and
two isochoric processes
11. The COP of Carnot Refrigerator is 3 and it produces 1 TR. The work that will be done is equal to
(a) 70 kJ/min
(b) 100 kJ/min
(c) 200 kJ/min
(d)
210 kJ/min
12. In Bell – Colemann refrigerator for the same temperature range
(a) COP of dense air system is
equal to COP of open air system
(b) COP of dense air system is
lower than COP of open air system
(c) COP of dense air
system is higher than COP of open air system
(d) COP of dense air system may be higher or lower than COP of open air system depending upon pressure ratio.
13. For very high speed planes cruising at Mach number 2.5 and above, the air craft refrigeration system recommended is
(a) Simple evaporative type
(b)
Boot-strap type
(c) Regenerative type
(d) Boot strap evaporative type
14. The air craft system giving Lowest Dry Air Rated Turbine discharge temperature at supersonic cruising speeds of the plane, is
(a) Reduced ambient system of
Refrigeration
(b) Boot-strap system of
Refrigeration
(c) Regenerative system of
Refrigeration
(d) Boot strap
evaporative system of Refrigeration
15. There are two cooling turbines
in
(a) Reduced ambient
system of Refrigeration
(b) Boot-strap system of
Refrigeration
(c) Regenerative system of
Refrigeration
(d) Boot strap evaporative system
of Refrigeration
16. There are two stages of
compression of air in
(a) Reduced ambient system of
Refrigeration
(b) Boot-strap system of Refrigeration
(c) Regenerative system of
Refrigeration
(d) Simple evaporative system of
Refrigeration
17. A Bell-Colemann cycle is
(a) reversed Carnot Cycle
(b) reversed Joule Cycle
(c) reversed Rankine cycle
(d) None of the above
18. In a refrigeration cycle the
heat is rejected by refrigerant at
(a) expansion valve
(b) compressor
(c) condenser
(d) all the above
19. A reversible refrigerator working between two fixed temperatures
(a) has the same COP
whatever the working substance
(b) has its COP increased for
working substance with high enthalpy of evaporation
(c) has its COP increased for
working substance with higher specific heats
(d) none of the above
