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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