The leakage in a refrigeration system using Freon is detected by
Halide torch
Sulphur sticks
Soap and water
All of these
Correct Answer :
A. Halide torch
Related Questions
When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be
Cooled and humidified
Cooled and dehumidified
Heated and humidified
Heated and dehumidified
In larger industrial and commercial reciprocating compression systems, refrigerant widely used is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
The desirable property of a refrigerant is
Low boiling point
High critical temperature
High latent heat of vaporisation
All of these
The temperature of air recorded by a thermometer, when it is not affected by the moisture present in the air, is called
Wet bulb temperature
Dry bulb temperature
Dew point temperature
None of these
Which of the following refrigerant has the highest freezing point.
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
A standard ice point temperature corresponds to the temperature of
Water at 0°C
Ice at 4°C
Solid and dry ice
Mixture of ice and water under equilibrium conditions
The power per tonne of refrigeration is
3.5/C.O.P.
C.O.P/3.5
3.5 × C.O.P.
None of these
The horizontal and non-uniformly spaced lines on a psychrometric chart indicates
Dry bulb temperature
Wet bulb temperature
Dew point temperature
Specific humidity
One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice
In 1 hour
In 1 minute
In 24 hours
In 12 hours
The COP of a vapour compression plant in comparison to vapour absorption plant is
More
Less
Same
More/less depending on size of plant
Rating of a domestic refrigerator is of the order of
0.1 ton
5 tons
10 tons
40 tons
A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be
1/4
1/3
3
4
The specific humidity during humidification process
Remains constant
Increases
Decreases
None of these
Mass flow ratio of NH₃ in comparison to Freon12 for same refrigeration load and same temperature limits is of the order of
1 : 1
1 : 9
9 : 1
1 : 3
Choose the correct statement
A refrigerant should have low latent heat
If operating temperature of system is low, then refrigerant with low boiling point should be used
Pre-cooling and sub-cooling bf refrigerant are same
Superheat and sensible heat of a refrigerant are same
The centrifugal compressors are generally used for refrigerants that require
Small displacements and low condensing pressures
Large displacements and high condensing pressures
Small displacements and high condensing pressures
Large displacements and low condensing pressures
The C.O.P. of a refrigerator working on a reversed Carnot cycle is (where T₁ = Lowest absolute temperature, and T₂ = Highest absolute temperature)
T₁ / (T₂ - T₁)
(T₂ - T₁)/T₁
(T₁ - T₂)/T₁
T₂/ (T₂ - T₁)
In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is
Less than 2 kg
More than or equal to 3.65 kg
More than 10 kg
There is no such consideration
Accumulators should have adequate volume to store refrigerant charge at least
10 %
25 %
50 %
75 %
Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system
Strong solution to weak solution
Weak solution to strong solution
Strong solution to ammonia vapour
Ammonia vapours to weak solution
The unit of thermal diffusivity is
m/hK
m/h
m²/h
m²/hK
Ammonia absorption refrigeration cycle requires
Very little work input
Maximum work input
Nearly same work input as for vapour compression cycle
Zero work input
Which of the following cycles uses air as the refrigerant?
Ericson
Stirling
Carnot
Bell Coleman
Condensing temperature in a refrigerator is the temperature
Of cooling medium
Of freezing zone
Of evaporator
At which refrigerant gas becomes liquid
A refrigerating system operating on reversed Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the end of constant pressure cooling is 300K and rise in the temperature of air in the refrigerator is 50 K, then the net work of compression will be (assume air as working substance with Cp = 1 kJ/kg)
25 kJ/kg
50 kJ/kg
100 kJ/kg
125 kJ/kg
The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure, is called
Humidity ratio
Relative humidity
Absolute humidity
Degree of saturation
The vapour pressure of refrigerant should be
Lower than atmospheric pressure
Higher than atmospheric pressure
Equal to atmospheric pressure
Could be anything
Under cooling in a refrigeration cycle
Increases C.O.P
Decreases C.O.P
C.O.P remains unaltered
Other factors decide C.O.P
Refrigeration in aeroplanes usually employs the following refrigerant
CO2
Freon-11
Freon-22
Air
Aqua ammonia is used as refrigerant in the following type of refrigeration system
Compression
Direct
Indirect
Absorption