In vapour compression cycle the condition of refrigerant is superheated vapour
After passing through the condenser
Before passing through the condenser
After passing through the expansion or throttle valve
Before entering the expansion valve
Correct Answer :
B. Before passing through the condenser
Related Questions
As relative humidity decreases, the dew point temperature will be ________ wet bulb temperature.
Same as
Lower than
Higher than
None of these
The wet bulb temperature at 100% relative humidity is ________ dew point temperature.
Same as
Lower than
Higher than
None of these
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)
The alignment circle is marked on the psychrometric chart at
20°C DBT and 50% RH
26°C DBT and 50% RH
20°C DBT and 60% RH
26°C DBT and 60% RH
A Bell Coleman refrigerator working on dense air system as compared to open air system, for the same range of temperature, results in ________ power per tonne of refrigeration.
Same
Lower
Higher
None of these
The dry bulb temperature during sensible heating of air
Remains constant
Increases
Decreases
None of these
The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, will
Increase
Decrease
May increase or decrease depending on the type of refrigerant used
Remain unaffected
Condensing temperature in a refrigerator is the temperature
Of cooling medium
Of freezing zone
Of evaporator
At which refrigerant gas becomes liquid
A mixture of dry air and water vapour, when the air has diffused the maximum amount of water vapour into it, is called
Dry air
Moist air
Saturated air
Specific humidity
In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is
Heated and dehumidified
Heated and humidified
Cooled and humidified
Cooled and dehumidified
The lowest thermal diffusivity is of
Iron
Lead
Aluminium
Rubber
The boiling point of ________ is 10.5°C.
Ammonia
R-12
Sulphur dioxide
Carbon dioxide
The boiling point of carbon dioxide is
-20.5°C
-50°C
-63.3°C
-78.3°C
Accumulators should have adequate volume to store refrigerant charge at least
10 %
25 %
50 %
75 %
The horizontal and non-uniformly spaced lines on a psychrometric chart indicates
Dry bulb temperature
Wet bulb temperature
Dew point temperature
Specific humidity
Environmental protection agencies advice against the use of chlorofluorocarbon refrigerants since
These react with water vapour and cause acid rain
These react with plants and cause greenhouse effect
These react with oxygen and cause its depletion
These react with ozone layer
A vapour absorption refrigeration system
Gives noisy operation
Gives quiet operation
Requires little power consumption
Cools below 0°C
Bell Coleman cycle is a
Reversed Carnot cycle
Reversed Otto cycle
Reversed Joule cycle
Reversed Rankine cycle
The fluids used in Electrolux refrigerator are
Water and hydrogen
Ammonia and hydrogen
Ammonia, water and hydrogen
None of these
Vapour compression refrigeration is somewhat like
Carnot cycle
Rankines cycle
Reversed Carnot cycle
None of the above
The process, generally used in winter air-conditioning to warm and humidity the air, is called
Humidification
Dehumidification
Heating and humidification
Cooling and dehumidification
In a reversed Brayton cycle, the heat is absorbed by the air during
Isentropic compression process
Constant pressure cooling process
Isentropic expansion process
Constant pressure expansion process
The difference between dry bulb temperature and wet bulb temperature, is called
Dry bulb depression
Wet bulb depression
Dew point depression
Degree of saturation
The desirable property of a refrigerant is
Low boiling point
High critical temperature
High latent heat of vaporisation
All of these
The specific humidity during humidification process
Remains constant
Increases
Decreases
None of these
In a refrigerating machine, heat rejected is _________ heat absorbed.
Equal to
Less than
Greater than
None of these
The formation of frost on cooling coils in a refrigerator
Increases heat transfer
Improves C.O.P. of the system
Increases power consumption
Reduces power consumption
A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be
1.33
2.33
3.33
4.33
The operating pressure for refrigerating units using R-12 as a refrigerant is
2 bar
8 bar
15 bar
30 bar
Which of the following refrigerants has lowest freezing point?
Freon-12
NH3
CO2
Freon-22