mcq-Refrigeration-vapor compression

mcq-Refrigeration-vapor compression

Most commonly used method of refrigeration is vapor compression refrigeration.Cooling capacity is the cooling produced per minute. Refrigeration is measured in tons of refrigeration. (1 ton = 211kJ/min of cooling effect). Cooling effect is caused by latent heat in vapor refrigeration while by sensible heat in gas refrigeration. Sub-cooling causes increase in COP of the system.

One ton of refrigeration is the heat removal at the rate of
(a) 211 kJ/min
(b) 211 kcal/min
(c) 211 BTU/min
(d) None
(Ans: a)

In gas refrigeration, cooling effect is produced by
(a) Latent heat
(b) Total heat
(c) Sensible heat
(d) None
(Ans:c)

In vapor compression refrigeration, cooling effect is produced by
(a) Latent heat
(b) Total heat
(c) Sensible heat
(d) None
(Ans:a)

Cooling effect is produced in the
(a) Condenser
(b) Expansion valve
(c) Evaporator
(d) None
(Ans:c)

Sub-cooling in a vapor compression refrigeration is always
(a) Undesirable
(b) Desire able
(c) Not known’
(d) None
(Ans: b)

Due to sub-cooling in vapor compression refrigeration, COP
(a) Decreases
(b) Increases
(c) Remains same
(d) None
(Ans: b)

High degree of super heat in vapor compression refrigeration, COP
(a) Decreases
(b) Increases
(c) Remains same
(d) None
(Ans: a)

Due to inter-cooling in multistage refrigeration, COP
(a) Decreases
(b) Increases
(c) Remains same
(d) None
(Ans: b)

As evaporator temperature decreases in vapor compression refrigeration, COP
(a) Decreases
(b) Increases
(c) Remains same
(d) None
(Ans: a)

As evaporator pressure decreases in vapor compression refrigeration, COP
(a) Decreases
(b) Increases
(c) Remains same
(d) None
(Ans: a)

As evaporator pressure decreases in vapor compression refrigeration, the cooling effect
(a) Increases
(b) Decreases
(c) Remains same
(d) None
(Ans: b)

As discharge pressure decreases in vapor compression refrigeration, the cooling effect
(a) Increases
(b) Decreases
(c) Remains same
(d) None
(Ans: a)

As condenser pressure decreases in vapor compression refrigeration, the cooling effect
(a) Increases
(b) Decreases
(c) Remains same
(d) None
(Ans: a)

The use of a flash chamber in a multi-stage vapor compression refrigeration

(a) increases the COP

(b) decreases the COP

(c) neither increases or decreases the COP

(d) None

(Ans: a)

 

 

The COP is maximum for a
(a) Vapor compression cycle
(b) Bell Coleman cycle
(c) Vapor absorption cycle
(d) None
(Ans: d)
In vapor compression refrigeration, COP is
(a) > 4
(b) <1
(c) >10
(d) None
(Ans:a)
In gas refrigeration, COP is
(a) > 4
(b) <1
(c) >10
(d) None
(Ans:b)

In Cascade refrigeration, COP is
(a) > 4
(b) <1
(c) >10
(d) None
(Ans:a)

The Cop of a heat pump is
(a) > COP of a refrigerator
(b) < COP of a refrigerator
(c) Equal to the COP of a refrigerator
(d) None
(Ans: a)

The COP of a heat pump operating between temperatures T1 and T2 is
(a) T1 + T2
(b) T1 – T2
(c) T12 — T22
(d) None
(Ans: d)

 

There is change of state of refrigerant is in relation to
(a) Bell Coleman Cycle
(b) Vapor compression Cycle
(c) Carnot cycle
(d) None
(Ans: b)

To improve the COP of a refrigeration system, the super heating in the evaporator should be
(a) High
(b) Low
(c) Zero
(d) None
(Ans:b)

To improve the COP of a refrigeration system, the sub-cooling in the condenser should be
(a) High
(b) Low
(c) Zero
(d) None
(Ans:a)

The cooling effect is higher in a
(a) Boot strap air refrigeration cycle
(b) Bell column cycle
(c) Vapor compression cycle
(d) None
(Ans: c)

The boiling point of a liquid increases with the
(a) Decrease of pressure
(b) Increase of pressure
(c) Increase of pressure and volume
(d) None
(Ans: b)

With the decrease of suction pressure, refrigeration effect
(a) Increases
(b) Decreases
(c) Remains the same
(d) None
(Ans: b)

With the increase of discharge pressure, the refrigerating effect
(a) Increases
(b) Decreases
(c) Remains the same
(d) None
(Ans: b)

With the decrease in suction pressure, COP of a refrigeration system
(a) Increases
(b) Decreases
(c) Remains the same
(d) None
(Ans: b)

With the decrease in discharge pressure, COP of a refrigeration system
(a) Increases
(b) Decreases
(c) Remains the same
(d) None
(Ans: a)

The accumulator in a refrigeration system is installed at the
(a) Inlet of compressor
(b) Inlet of evaporator
(c) Inlet of expansion valve
(d) None
(Ans:a)

The condenser used in a small cooling capacity plant is

(a) Air cooled

(b) Water cooled

(c) Air as well as water cooled

(d) None

(Ans: a)

The condenser used in medium cooling capacity plant is

(a) Air cooled

(b) Water cooled

(c) Air as well as water cooled

(d) None

(Ans: b)

The condenser used in large cooling capacity plant is

(a) Air cooled

(b) Water cooled

(c) Air as well as water cooled

(d) None

(Ans: c)