GAS REFRIGERATION MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

GAS REFRIGERATION

MULTIPLE CHOICE QUESTIONS

(MCQ) WITH ANSWERS

COP of gas refrigeration is much

less than one. All the aircrafts use Gas refrigeration

 because of easy availability, free, safe & eco-friendly

nature of air as refrigerant.

Fig. Bell-Coleman Cycle

Fig. Bell Coleman Cycle on Temperature-Entropy Chart

  1. A gas refrigeration works on
  1. Carnot Cycle
  2. Rankine Cycle
  3. Brayton Cycle
  4. None

ANS: (d)

  1. A gas refrigeration works on
  1. Reversed Carnot Cycle
  2. Rankine Cycle
  3. Reversed Brayton Cycle
  4. None

ANS: (c)

  1. In gas refrigeration, cooling effect is by
  1. Sensible heat effect
  2. Latent heat effect
  3. Both (a) & (b)
  4. None

ANS: (a)

  1. In gas refrigeration, replacement of evaporator is by a
  1. Boiler
  2. Refrigerator
  3. Both (a) & (b)
  4. None

ANS: (b)

  1. In gas refrigeration, replacement of condenser is by a
  1. Refrigerator
  2. Boiler
  3. Cooler
  4. None

ANS: (c )

  1. COP of gas refrigeration is
  1. >1
  2. <1
  3. = 1
  4. None

ANS: (b)

  1. In gas refrigeration, replace expansion valve by
  1. Refrigerator
  2. Compressor
  3. Turbine
  4. None

ANS: (c )

  1. In gas refrigeration, COP is
  1. Cooling effect/Work input in compressor
  2. Work input in compressor/Cooling effect
  3. Cooling effect/Net work done
  4. None

ANS: (c )

  1. Use of Gas refrigeration is in
  1. Refrigerated trucks
  2. Refrigerators
  3. Aircrafts
  4. None

ANS: (c )

  1. Why to use gas refrigeration in aircrafts?
  1. Less weight of refrigeration equipment
  2. More weight of refrigeration equipment
  3. Same weight as in vapor compression refrigeration
  4. None

ANS: (a)

  1. In gas refrigeration, temperature drop across expander is
  1.  High
  2.  Low
  3. No drop
  4. None

ANS: (a)

  1. Gas refrigeration is more harmful than vapor compression refrigeration
  1. Yes
  2. No
  3. Can’t say
  4. None

ANS: (b)

  1. In gas refrigeration, which one is not present
  1. Compressor
  2. Turbine
  3. Generator
  4. None

ANS: (c )

  1. In gas refrigeration, cooling in cooler is by
  1. Water
  2. Brine
  3. Air
  4. None

ANS: (c )

  1. The compressor used in gas refrigeration is
  1. Reciprocating
  2. Rotary
  3. Centrifugal
  4. None

ANS: (c )

  1. The theoretical expansion process in gas refrigeration is
  1. Isentropic
  2. Isothermal
  3. Isobaric
  4. None

ANS: (a)

  1. The theoretical compression process used in gas refrigeration is
  1. Isentropic
  2. Isothermal
  3. Isobaric
  4. None

ANS: (a)

  1. The size of cooler in gas refrigeration as compared to condenser in vapor compression refrigeration is
  1. Smaller
  2. Equal
  3. Larger
  4. None

ANS: (c )

  1. The temperature after expansion in gas refrigeration is
  1. Above 00C
  2. Below 00C
  3. Can’t say
  4. None

ANS: (b)

  1. Secondary refrigerant used in gas refrigeration
  1. Ammonia
  2. Freon
  3. Water
  4. None

ANS: (d)

  1.  Gas refrigeration uses brine solution as secondary refrigerant
  1. Yes
  2. No
  3. Can’t say
  4. None

ANS: (b)

  1. Cooling effect in gas refrigeration is
  1. m. (h1-h4)
  2. m.cp Δt
  3. m. Latent heat
  4. None

ANS: (b)

  1. The work done in the compressor of gas refrigeration is
  1. m. (h2-h1)
  2. m.cp (t2-t1)
  3. m. Latent heat
  4. None

ANS: (b)

  1. The work done in the expander of gas refrigeration is
  1. m. (h3-h4)
  2. m.cp (t3-t4)
  3. m. cv (t3-t4)
  4. None

ANS: (b)

  1. The heat lost in the cooler of gas refrigeration is
  1. m. (h2-h3)
  2. m.cp (t2-t3)
  3. m. cv (t2-t3)
  4. None

ANS: (b)

26. In simple aircraft cooling system, there are

(a) Two compressors

(b) one turbine

(c) Two heat exchangers

(d) None

ANS: (b)

27. In simple aircraft cooling system with evaporator, there are

(a) Two compressors

(b) Two turbines

(c) two heat exchangers

(d) None

ANS: (c)

28. In boot strap aircraft cooling system, there are

(a) Two compressors

(b) Two turbines

(c) One heat exchanger

(d) None

ANS: (a)

29. In boot strap aircraft cooling system with evaporator , there are

(a) Three compressors

(b) Two turbines

(c) Three heat exchangers

(d) None

ANS: (c)

30. In regenerative aircraft cooling system, there are

(a) Two compressors

(b) Two turbines

(c) One heat exchanger

(d) None

ANS: (d)

31. In regenerative aircraft cooling system, there are

(a) Two compressors

(b) Two turbines

(c) Two heat exchanger

(d) None

ANS: (c)

32. In a reduced ambient aircraft cooling system, there are

(a) Two compressors

(b) Two turbines

(c) One heat exchanger

(d) None

ANS: (b)

33. In a simple aircraft cooling system, maximum cooling is available on

(a) ground

(b) Maximum height

(c) Both (a) & (b)

(d) None

ANS: (a)

34. DART stands for dry air rated temperature at the

(a) Inlet of main compressor

(b) Inlet of turbine

(c) Both (a) & (b)

(d) None

ANS: (d)

35.DART stands for dry air rated temperature at the

(a) Outlet of main compressor

(b) Outlet of turbine

(c) Both (a) & (b)

(d) None

ANS: (b)

36. The simple cooling system for aircraft is suitable for Mach number

(a) High

(b) Low

(c) Both (a) & (b)

(d) None

ANS: (b)

37. At high Mach numbers, cooling system of aircraft is

(a) Boot strap

(b) Regenerative

(c) Both (a) & (b)

(d) None

ANS: (c)

38. Reduced ambient aircraft cooling system suits for

(a) Low Mach Number

(b) High Mach Number

(c) Mach number =2

(d) None

ANS: (b)

39. DART increases with the

(a) Decrease of Mach Number

(b) Increase of Mach Number

(c) Both (a) & (b)

(d) None

ANS: (a)

40. Desirable DART is

(a) Low

(b) High

(c) Medium

(d) None

ANS: (a)

41. With isentropic compression and expansion in a reversed Brayton Cycle, the COP is

(a) (T1 – T4)/[(T1-T4)-(T1-T2)]

(b) (T1 – T4)/[(T1-T2)-(T1-T4)]

(c) (T1 – T4)/[(T1-T2)-(T2-T4)]

(d) None

ANS: (b)

42. With adiabatic compression and expansion in a reversed Brayton Cycle, the COP is

(a) (T1 – T4)/[(T1-T4)-(T1-T2)]

(b) (T1 – T4)/(n/(n-1))((γ-1)/γ))[(T1-T2)-(T1-T4)]

(c) (T1 – T4)/((n-2)/(n-1))((γ-1)/γ))[(T1-T2)-(T2-T4)]

(d) None

ANS: (b)

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