Refrigeration Interview Questions and Answers for freshers on “Open Air Refrigeration System – 2”.
1. What is the common application of Air standard refrigeration system?
a) Domestic refrigerators
b) Aircraft air conditioning
c) Cold storage
d) Car air conditioning system
Clarification: As sufficient amount of air is obtained while aviation of air crafts, the only thing is to reduce its velocity, and then it can be used for air conditioning in air crafts.
2. Why is a nozzle used in a steam jet refrigeration system?
a) To convert the high pressure motive steam into high velocity steam
b) To reduce energy consumption
c) To improve safety aspects
d) To improve thermal conductivity
Clarification: Nozzle is a device which has one of its end converging whereas the other end diverging, when the steam enters from larger end and exit at smaller end, its velocity increases that produces Jet effect. Hence nozzle is used for it.
3. Which properties are essential for thermoelectric refrigeration?
a) High electrical and thermal conductivity
b) Low electrical and thermal conductivity
c) Low electrical conductivity and high thermal conductivity
d) High electrical conductivity and low thermal conductivity
Clarification: For producing thermoelectric effect, high thermal conductivity is a desirable property, but for producing refrigerating effect the thermal conductivity should be lowest to reduce the loss of cooling due to conduction through walls.
4. Why is fast freezing done in various products ?
a) To reduce the cell damage due to ice crystal growth.
b) To reduce energy consumption of refrigerator
c) To reduce the bacterial activity
d) To save time
Clarification: If the refrigeration in allowed to occur at a slow rate, the cells may get damage due to ice formation in the form of crystals because of the moisture content present in it.
5. In a refrigerating machine, heat rejected is ________ the heat absorbed.
a) equal to
b) less than
c) in unity with
d) greater than
Clarification: Heat rejected in refrigerating machine is always more than the heat absorbed because as the evaporation increases i.e. heat rejection, more will be the refrigerating effect.
6. What is NOT one of the advantages of using closed Air Refrigeration system?
a) Lighter in weight
b) Compact in construction
c) Environmental Friendly
d) Lower co-efficient of performance
Clarification: Air refrigeration system is used mainly due to light in weight, smaller and environment friendly due to use of air as refrigerant. Also it has higher co-efficient of performance.
7. Reduction in operating pressure in the Air refrigeration cycle results in _________
a) increase in C.O.P.
b) decrease in C.O.P.
c) no change in C.O.P.
d) always decreases
Clarification: As the operating pressure reduces, the change in work done decreases. Hence the C.O.P of refrigeration increases.
8. How is the refrigerant used in the Air refrigeration cycle?
a) In the condenser
b) In the compressor
c) Directly in contact
d) Not used at all
Clarification: Refrigerant used in Air refrigeration cycle is pure air, and it’s used directly in contact with the area of refrigeration. Whereas in Expansion refrigeration, refrigerants are used in condensers etc.