Highest pressure encountered in a refrigeration system should be
Critical pressure of refrigerant
Much below critical pressure
Much above critical pressure
Near critical pressure
Correct Answer :
B. Much below critical pressure
Related Questions
Which of the following statement is correct?
In vapour absorption refrigerator, the compression of refrigerant is avoided.
Sub-cooling can be achieved by circulating more quantity of cooling water through the condenser.
In vapour compression refrigeration, the vapour is drawn in the compressor cylinder during its suction stroke and is compressed adiabatically during the compression stroke.
All of the above
In aqua ammonia and Lithium bromide water absorption refrigeration systems, the refrigerants are respectively
Water and water
Water and lithium bromide
Ammonia and lithium bromide
Ammonia and water
If a gas is to be liquefied, its temperature must be
Increased to a value above its critical temperature
Reduced to a value below its critical temperature
Equal to critical temperature
None of the above
The thermostatic expansion valve operates on the changes in the
Degree of superheat at exit from the evaporator
Temperature of the evaporator
Pressure in the evaporator
None of the above
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 pressure at the outlet of a refrigerant compressor is called
Suction pressure
Discharge pressure
Critical pressure
Back pressure
During adiabatic saturation process on unsaturated air __________ remains constant.
Relative humidity
Dew point temperature
Dry bulb temperature
Wet bulb temperature
In a refrigeration system, heat absorbed in comparison to heat rejected is
More
Less
Same
More for small capacity and less for high capacity
In chemical dehumidification process,
Dew point temperature decreases
Wet bulb temperature decreases
Dry bulb temperature increases
All of these
The evolution of heat of solution takes place in ammonia absorption plant when
Ammonia vapour goes into solution
Ammonia vapour is driven out of solution
Lithium bromide mixes with ammonia
Weak solution mixes with strong solution
The wet bulb depression indicates _________ humidity of the air.
Absolute
Relative
Specific
None of these
Condensing temperature in a refrigerator is the temperature
Of cooling medium
Of freezing zone
Of evaporator
At which refrigerant gas becomes liquid
The air cooling system mostly used in transport type aircrafts is
Simple air cooling system
Simple evaporative air cooling system
Bootstrap air cooling system
All of these
Presence of moisture in a refrigerant affects the working of
Compressor
Condenser
Evaporator
Expansion valve
The specific humidity during humidification process
Remains constant
Increases
Decreases
None of these
An infinite parallel planes with emissivities e₁ and e₂, the interchange factor for radiation from surface 1 to surface 2 is given by
(e₁ + e₂)/ e₁ + e₂ - e₁e₂
1/e₁ + 1/e₂
e₁ + e₂
e₁e₂
In Electrolux refrigerator
Ammonia is absorbed in hydrogen
Ammonia is absorbed in water
Ammonia evaporates in hydrogen
Hydrogen evaporates in ammonia
The coefficient of performance of Heat Pump is always __________ one.
Equal to
Less than
Greater than
None of these
While designing the refrigeration system of an aircraft, the prime consideration is that the
System has high C.O.P.
Power per TR is low
Mass of refrigerant circulated in the system is low
Mass of the refrigeration equipment is low
The humidity ratio or specific humidity is the mass of water vapour present in
1 m3 of wet air
1 m3 of dry air
1 kg of wet air
1 kg of dry air
A bootstrap air cooling system has
One heat exchanger
Two heat exchangers
Three heat exchangers
Four heat exchangers
The process, generally used in winter air-conditioning to warm and humidity the air, is called
Humidification
Dehumidification
Heating and humidification
Cooling and dehumidification
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 boiling point of ammonia is
100°C
50°C
33.3°C
0°C
The refrigerant for a refrigerator should have
High sensible heat
High total heat
High latent heat
Low latent heat
Oil separator in a refrigeration cycle is installed
Before compressor
Between compressor and condenser
Between condenser and evaporator
Between condenser and expansion valve
The human body feels comfortable when the heat stored in the body is
Positive
Negative
Zero
None of these
The humidification process, on the psychrometric chart is shown by
Horizontal line
Vertical line
Inclined line
Curved line
Vapour compression refrigeration is somewhat like
Carnot cycle
Rankines cycle
Reversed Carnot cycle
None of the above
The conditioned air supplied to the room must have the capacity to take up
Room sensible heat load only
Room latent heat load only
Both room sensible heat and latent heat loads
None of the above