The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P.
More
Less
Equally
Unpredictable
Correct Answer :
A. More
Related Questions
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
One ton refrigeration corresponds to
50 kcal/ min
50 kcal/ hr
80 kcal/ min
80 kcal/ hr
Presence of moisture in a refrigerant affects the working of
Compressor
Condenser
Evaporator
Expansion valve
The wet bulb temperature during sensible cooling of air
Remains constant
Increases
Decreases
None of these
Mass flow ratio of NH₃ in comparison to Freon12 for same refrigeration load and same temperature limits is of the order of
1 : 1
1 : 9
9 : 1
1 : 3
Chaperon equation is a relation between
Temperature, pressure and enthalpy
Specific volume and enthalpy
Temperature and enthalpy
Temperature, pressure, specific volume and enthalpy
Rating of a domestic refrigerator is of the order of
0.1 ton
5 tons
10 tons
40 tons
In a bootstrap air evaporative cooling system, the evaporator is provided
Between the combustion chamber and the first heat exchanger
Between the first heat exchanger and the secondary compressor
Between the secondary compressor and the second heat exchanger
Between the second heat exchanger and the cooling turbine
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
The wet bulb temperature during sensible heating of air
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
In vapour compression cycle, the condition of refrigerant is very wet vapour
After passing through the condenser
Before passing through the condenser
After passing through the expansion or throttle valve
Before entering the compressor
The refrigerant used in small tonnage commercial machines (hermetically sealed units) is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
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
In air-conditioning of aeroplanes, using air as a refrigerant, the cycle used is
Reversed Carnot cycle
Reversed Joule cycle
Reversed Brayton cycle
Reversed Otto cycle
The refrigerant widely used in domestic refrigerators is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
The heat rejection factor (HRF) is given by
1 + C.O.P
1 - C.O.P.
1 + (1/C.O.P)
1 - (1/C.O.P)
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)
Condensing temperature in a refrigerator is the temperature
Of cooling medium
Of freezing zone
Of evaporator
At which refrigerant gas becomes liquid
The Freon group of refrigerants are
Halocarbon refrigerants
Zoetrope refrigerants
Inorganic refrigerants
Hydrocarbon refrigerants
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
Which of the following statement is correct?
The human body can lose heat even if its temperature is less than the atmospheric temperature.
The increase in air movement increases the evaporation from the human body.
The warm air increases the rate of radiation of heat from the human body.
Both (A) and (B)
The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)
25°C DBT and 100% RH
20°C DBT and 80% RH
22°C DBT and 60% RH
25°C DBT and 40% RH
During sensible cooling of air ________ decreases.
Wet bulb temperature
Relative humidity
Dry bulb temperature
Specific humidity
During dehumidification process, the relative humidity
Remains constant
Increases
Decreases
None of these
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
Rick up the incorrect statement
Lithium bromide used in vapour absorption cycle is non volatile
Lithium bromide plant can't operate below 0°C
A separator is used in lithium bromide plant to remove the unwanted water vapour by condensing
Concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator
The thermal diffusivity for gases is generally __________ those for liquids.
Equal to
Less than
Greater than
None of these
An important characteristic of absorption system of refrigeration is
Noisy operation
Quiet operation
Cooling below 0°C
Very little power consumption
Highest temperature encountered in refrigeration cycle should be
Near critical temperature of refrigerant
Above critical temperature
At critical Temperature
Much below critical temperature