Highest temperature encountered in refrigeration cycle should be
Near critical temperature of refrigerant
Above critical temperature
At critical Temperature
Much below critical temperature
Correct Answer :
D. Much below critical temperature
Related Questions
The freezing point of R-12 is
-86.6°C
-95.2°C
-107.7°C
-135.8°C
Air refrigeration operates on
Carnot cycle
Reversed Carnot cycle
Rankines cycle
Brayton cycle
The undesirable property of a refrigerant is
Non-toxic
Non-flammable
Non-explosive
High boiling point
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 refrigerant used in small tonnage commercial machines (hermetically sealed units) is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by
Liquid pump
Generator
Absorber and generator
Absorber, generator and liquid pump
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
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 pressure at the inlet of a refrigerant compressor is called
Suction pressure
Discharge pressure
Critical pressure
Back pressure
The process, generally used in summer air conditioning to cool and dehumidify the air, is called
Humidification
Dehumidification
Heating and humidification
Cooling and dehumidification
The fluids used in Electrolux refrigerator are
Water and hydrogen
Ammonia and hydrogen
Ammonia, water and hydrogen
None of these
During sensible cooling of air ________ decreases.
Wet bulb temperature
Relative humidity
Dry bulb temperature
Specific humidity
The reciprocating refrigerant compressors are very suitable for
Small displacements and low condensing pressures
Large displacements and high condensing pressures
Small displacements and high condensing pressures
Large displacements and low condensing pressures
On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process
Involves no change in volume
Takes place at constant temperature
Takes place at constant entropy
Takes place at constant pressure
The wet bulb temperature at 100% relative humidity is ________ dew point temperature.
Same as
Lower than
Higher than
None of these
Cooling water is required for following equipment in ammonia absorption plant
Condenser
Evaporator
Absorber
Condenser, absorber and separator (rectifier)
In vapour compression cycle the condition off refrigerant is dry saturated vapour
After passing through the condenser
Before passing through the condenser
After passing through the expansion or throttle valve
Before entering the compressor
The superheating in a refrigeration cycle
Does not alter C.O.P.
Increases C.O.P.
Decreases C.O.P.
None of these
A vapour absorption refrigeration system
Gives noisy operation
Gives quiet operation
Requires little power consumption
Cools below 0°C
In Electrolux refrigerator
Ammonia is absorbed in hydrogen
Ammonia is absorbed in water
Ammonia evaporates in hydrogen
Hydrogen evaporates in ammonia
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
During cooling and dehumidification, dry bulb temperature
Remains constant
Increases
Decreases
None of these
For air conditioning the operation theatre in a hospital, the percentage of outside air in the air supplied is
Zero
20
50
100
The moisture in a refrigerant is removed by
Evaporator
Safety relief valve
Dehumidifier
Driers
A vapour absorption refrigerator uses __________ as a refrigerant.
Water
Ammonia
Freon
Aqua-ammonia
During humidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
Which of the following refrigerant is highly toxic and flammable?
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases,
Will be higher
Will be lower
Will remain unaffected
May be higher or lower depending upon the nature of noncondensable gases
Chaperon equation is a relation between
Temperature, pressure and enthalpy
Specific volume and enthalpy
Temperature and enthalpy
Temperature, pressure, specific volume and enthalpy
The coefficient of performance of Heat Pump is always __________ one.
Equal to
Less than
Greater than
None of these