Vapour Compression Refrigeration

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This set of Refrigeration and Air conditioning Multiple Choice Questions & Answers (MCQs) focuses on Vapour Compression Refrigeration

Q1 | Wet compression vapour compression refrigeration cycle means
  • Vapour compression takes place in wet region
  • Vapour compression in dry region, but evaporation in wet region
  • vapour compression in wet region, but leaves in superheated region
  • None of the above
Q2 | For simple saturated vapour compression refrigeration cycle operating between 5°C and 40°C, and the refrigerants being R-11, R-12, R-717 and R-22, the evaporator pressure is highest for
  • R-11
  • R-12
  • R-717
  • R-22
Q3 | With reciprocating compressor in vapour compression refrigeration system, wet compression is not desirable because
  • liquid trapped up in the head of cylinder may damage the compressor valves
  • COP of the cycle decreases
  • volumetric efficiency of compressor decreases
  • mass flow rate per ton of refrigerant increases
Q4 | An ideal refrigerant should have
  • low latent heat of vaporization
  • lower critical temperature
  • lower boiling point
  • high specific volume of vapour
Q5 | During compression in a vapour compression cycle the refrigerant is super heated
  • C.O.P is reduced
  • C.O.P is increased
  • Work done is reduced
  • Refrigerating effect is reduced
Q6 | Heat is absorbed by a refrigerant, during a refrigeration cycle in a
  • condenser
  • evaporator
  • compressor
  • throttle valve
Q7 | What is the effect of frost on the cooling coils of the evaporator of refrigeration system
  • It reduces the life of cooling coils
  • It increases the compressor pressure
  • It makes the compressor run for comparatively short runs
  • It acts as the insulator and decreases the heat transfer rate
Q8 | The widely used refrigerant in domestic refrigerators is
  • Carbon-dioxide
  • Sulphur dioxide
  • Freon-12
  • Ammonia
Q9 | Freon group refrigerants are
  • toxic
  • inflamma
  • nontoxic and inflammable
  • non- toxic & non-inflammable
Q10 | Latent heat of vaporization of a refrigerant ,at lower temperatures and pressures
  • increase
  • decreases
  • remains constant
  • unpredictable
Q11 | The refrigerant with highest critical pressure is
  • Carbon dioxide
  • Ammonia
  • Freon-11
  • Freon-22
Q12 | The Refrigerant commonly used in commercial ice plants is
  • Carbon-dioxide
  • Air
  • Ammonia
  • Freon-12
Q13 | Which of the following refrigerants has the lowest boiling point?
  • Freon-12
  • Carbon-dioxide
  • Ammonia
  • Sulphur dioxide
Q14 | In a flooded type of Evaporator which of the following types of expansion device is utilized
  • Float Valve
  • Thermostatic device
  • Capillary tube
  • Self actuated expansion valve
Q15 | Which of the following statements are TRUE?
  • A capillary tube is a variable opening area type expansion device
  • In a capillary tube pressure drop takes place due to fluid friction
  • In a capillary tube pressure drop takes place due to fluid acceleration
  • In a capillary tube pressure drop takes place due to fluid friction and acceleration
Q16 | Co-efficient of performance of vapour absorption refrigeration system as compared to that for vapour compression refrigeration system is
  • more
  • less
  • may be more or less
  • un - predictable
Q17 | The function of compressor in vapour compression refrigeration system is performed in vapour absorption system by
  • generator
  • absorber
  • generator, absorber and liquid pump
  • absorber and liquid pump
Q18 | In vapour absorption refrigeration system heating in generator is done at 100°C, refrigeration in evaporator at 10°C and cooling by cooling water in condenser at 30°C. The (COP)max is
  • 0.5
  • 0.35
  • 2
  • in sufficient data
Q19 | Electrolux system of refrigeration has
  • only one liquid pump
  • only two liquid pumps
  • no liquid pump
  • none of the above
Q20 | Electrolux refrigerators has the following working substances
  • Hydrogen
  • Ammonia and Hydrogen
  • Ammonia and water
  • Ammonia, hydrogen and water
Q21 | Which of the following system can be called as mechanical system of refrigeration
  • Vapour absorption system
  • Vapour compression system
  • Steam jet refrigeration system
  • None of the above
Q22 | The vapour absorption refrigeration system using Ammonia – water has cycle operating pressures
  • higher than that using Lithium Bromide – water
  • lower than that using Lithium Bromide – water
  • may be higher or lower depending upon application
  • higher for sub-zero application and lower for above zero application
Q23 | Shaft work required for vapour absorption system to produce 1 ton refrigeration may be only
  • 50 to 60% of that required for vapour compression system
  • 20 to 30% of that required for vapour compression system
  • 1 to 2% of that required for vapour compression system
  • none of the above
Q24 | Work of compression of the fluid in vapour absorption refrigeration system as compared to that for vapour compression refrigeration system is
  • les
  • more
  • may be more or less
  • un - predictable
Q25 | Munters Platen system of refrigeration is
  • Vapour absorption system with ammonia and water
  • Vapour compression system with ammonia as working substance
  • Electrolux system with Hydrogen, ammonia and water as working substances
  • none of the above