In mechanical refrigeration system, the refrigerant has the maximum temperature
In evaporator
Before expansion valve
Between compressor and condenser
Between condenser and evaporator
Correct Answer :
C. Between compressor and condenser
Related Questions
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
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 a vapour compression system, the condition of refrigerant is dry saturated vapour
Before entering the compressor
After leaving the compressor
Before entering the condenser
After leaving the condenser
The moisture in a refrigerant is removed by
Evaporator
Safety relief valve
Dehumidifier
Driers
A refrigerant with the highest critical pressure is
R-11
R-12
R-22
Ammonia
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
In a vapour compression cycle, the refrigerant immediately after expansion valve is
Liquid
Sub-cooled liquid
Saturated liquid
Wet vapour
Most air cooled condensers are designed to operate with a temperature difference of
5°C
8°C
14°C
22°C
In larger industrial and commercial reciprocating compression systems, refrigerant widely used is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
Air refrigeration cycle is used in
Domestic refrigerators
Commercial refrigerators
Air conditioning
Gas liquefaction
The material of pipe lines for a system using Freon as a refrigerant should be
Brass
Copper
Steel
Aluminium
During humidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
The undesirable property of a refrigerant is
Non-toxic
Non-flammable
Non-explosive
High boiling point
Which of the following refrigerant has the lowest boiling point?
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
Most of the domestic refrigerators work on the following refrigeration system
Vapour compression
Vapour absorption
Carnot cycle
Electrolux refrigerator
The minimum temperature to which water can be cooled in a cooling tower is
Dew point temperature of air
Wet bulb temperature of air
Dry bulb temperature of air
Ambient air temperature
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
In vapour compression cycle using NH₃ as refrigerant, initial charge is filled at
Suction of compressor
Delivery of compressor
High pressure side close to receiver
Low pressure side near receiver
The bypass factor for a cooling coil
Increases with increase in velocity of air passing through it
Decreases with increase in velocity of air passing through it
Remains unchanged with increase in velocity of air passing through it
May increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering
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 coefficient of performance of Electrolux refrigerator is the ratio of
Heat supplied by the gas burner to the heat absorbed by the evaporator
Heat absorbed by the evaporator to the heat supplied by the gas burner
Heat supplied by the gas burner minus the heat absorbed by the evaporator to the heat supplied by the gas burner
Heat absorbed by the evaporator minus the heat supplied by the gas burner to the heat absorbed by the evaporator
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 operating pressure for refrigerating units using R-12 as a refrigerant is
2 bar
8 bar
15 bar
30 bar
R-12 is generally preferred over R-22 in deep freezers since
It has low operating pressures
It gives higher coefficient of performance
It is miscible with oil over large range of temperatures
All 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
A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be
1 kW
2 kW
3 kW
4 kW
The sensible heat factor during the heating and humidification process is given by (where h₁ = Enthalpy of air entering the heating coil, h₂ = Enthalpy of air leaving the heating coil, and hA = Enthalpy of air at the end of humidification process)
(hA - h2)/ (h1 - h2)
(h2 - hA)/ (h1 - h2)
(h1 - h2)/ (hA - h2)
(hA - h1)/ (h2 - h1)
The refrigerant widely used in domestic refrigerators is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
Highest temperature encountered in refrigeration cycle should be
Near critical temperature of refrigerant
Above critical temperature
At critical Temperature
Much below critical temperature
In a refrigeration cycle, the flow of refrigerant is controlled by
Compressor
Condenser
Evaporator
Expansion valve