Presence of moisture in a refrigerant affects the working of
Compressor
Condenser
Evaporator
Expansion valve
Correct Answer :
D. Expansion valve
Related Questions
The moisture in a refrigerant is removed by
Evaporator
Safety relief valve
Dehumidifier
Driers
The reduced ambient air cooling system has
One cooling turbine and one heat exchanger
One cooling turbine and two heat exchangers
Two cooling turbines and one heat exchanger
Two cooling turbines and two heat exchangers
During heating and dehumidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is
Same
More
Less
More or less depending on ambient conditions
The leakage in a refrigeration system using ammonia is detected by
Halide torch
Sulphur sticks
Soap and water
All of these
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
In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = Bypass factor)
B.P.F. - 1
1 - B. P.F.
1/ B.P.F.
1 + B.P.F.
During dehumidification process, __________ remains constant.
Wet bulb temperature
Relative humidity
Dry bulb temperature
Specific humidity
During adiabatic saturation process on unsaturated air __________ remains constant.
Relative humidity
Dew point temperature
Dry bulb temperature
Wet bulb temperature
Hydrogen is used in Electrolux refrigeration system so as to _________ the rate of evaporation of the liquid ammonia passing through the evaporator.
Equalise
Reduce
Increase
None of these
Relative humidity is given by (where pv = Partial pressure of water vapour, pb = Barometric pressure, ps = Pressure of saturated air, pd = Pressure at dry bulb temperature, pw = Saturation pressure corresponding to wet bulb temperature, and μ = Degree of saturation)
0.622 Pv / (Pb - Pv)
μ/[1 - (1 - μ) (Ps/Pb)]
[Pv (Pb - Pd)]/ [Pd (Pb - Pv)]
None of these
The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy diagram represents
Condensation of the refrigerant vapour
Evaporation of the refrigerant liquid
Compression of the refrigerant vapour
Metering of the refrigerant liquid
The ratio of heat extracted in the refrigerator to the work-done on the refrigerant is called
Coefficient of performance of refrigeration
Coefficient of performance of heat pump
Relative coefficient of performance
Refrigerating efficiency
The leaks in a refrigeration system using Freon are detected by
Halide torch which on detection produces greenish flame lighting
Sulphur sticks which on detection gives white smoke
Using reagents
Smelling
Refrigeration in aeroplanes usually employs the following refrigerant
CO2
Freon-11
Freon-22
Air
In a domestic vapour compression refrigerator, the refrigerant commonly used is
CO₂
Ammonia
R-12
All of these
Chaperon equation is applicable for registration at
Saturation point of vapour
Saturation point of liquid
Sublimation temperature
Triple point
Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?
Ammonia
Carbon dioxide
Sulphur dioxide
Fluorine
The condition of refrigerant after passing through the condenser in a vapour compression system is
Saturated liquid
Wet vapour
Dry saturated vapour
Superheated vapour
Which of the following statement is wrong?
The value of C.O.P. is always greater than one.
In a vapour compression system, the condition of refrigerant before entering the compressor is dry saturated vapour.
The space between the saturated liquid line and saturated vapour line, in a pressure enthalpy chart, is wet vapour region.
None of the above
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 evaporator used in household refrigerators is
Frosting evaporator
Non-frosting evaporator
Defrosting evaporator
None of these
An important characteristic of absorption system of refrigeration is
Noisy operation
Quiet operation
Cooling below 0°C
Very little power consumption
A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. The Carnot coefficient of performance of cycle will be
0.2
1.2
5
6
For obtaining high COP, the pressure range of compressor should be
High
Low
Optimum
Any value
The process of under-cooling is generally brought about by
Circulating more quantity of cooling water through the condenser
Using water colder than the main circulating water
Employing a heat exchanger
Any one of the above
The thermal diffusivity for gases is generally __________ those for liquids.
Equal to
Less than
Greater than
None of these
The refrigerant after condensation process is cooled below the saturation temperature before throttling. Such a process is called
Sub-cooling or under-cooling
Super-cooling
Normal cooling
None of these
The curved lines on a psychrometric chart indicates
Dry bulb temperature
Wet bulb temperature
Dew point temperature
Relative humidity
The C.O.P. of a Carnot refrigerator in winter will be _________ as compared to C.O.P. in summer.
Same
Lower
Higher
None of these