The leakage in a refrigeration system using ammonia is detected by
Halide torch
Sulphur sticks
Soap and water
All of these
Correct Answer :
B. Sulphur sticks
Related Questions
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
In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be
High, of the order of 25°
As low as possible (3 to 11°C)
Zero
Any value
The capillary tube, as an expansion device, is used in
Domestic refrigerators
Water coolers
Room air conditioners
All of these
The leakage in a refrigeration system using Freon is detected by
Halide torch
Sulphur sticks
Soap and water
All of these
The lowest thermal diffusivity is of
Iron
Lead
Aluminium
Rubber
The atmospheric air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The bypass factor of the heating coil is
0.376
0.4
0.6
0.67
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 advantage of dry compression is that
It permits higher speeds to be used
It permits complete evaporation in the evaporator
It results in high volumetric and mechanical efficiency
All of the above
The wet bulb temperature during sensible heating of air
Remains constant
Increases
Decreases
None of these
An important characteristic of absorption system of refrigeration is
Noisy operation
Quiet operation
Cooling below 0°C
Very little power consumption
In actual air-conditioning applications for R-12 and R-22, and operating at a condenser temperature of 40° C and an evaporator temperature of 5° C, the heat rejection factor is about
1
1.25
2.15
5.12
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
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
In vapour compression cycle, the condition of refrigerant is saturated liquid
After passing through the condenser
Before passing through the condenser
After passing through the expansion throttle valve
Before entering the expansion valve
The horizontal and non-uniformly spaced lines on a psychrometric chart indicates
Dry bulb temperature
Wet bulb temperature
Dew point temperature
Specific humidity
The total pressure exerted by the mixture of air and water vapour is equal to the sum of pressures which each constituent would exert, if it occupied the same space by itself. This statement is called
Kinetic theory of gases
Newton's law of gases
Dalton's law of partial pressures
Avogadro's hypothesis
The temperature of air recorded by a thermometer, when its bulb is surrounded by a wet cloth exposed to the air, is called
Wet bulb temperature
Dry bulb temperature
Dew point temperature
None of these
The coefficient of performance of Heat Pump is always __________ one.
Equal to
Less than
Greater than
None of these
The temperature of ammonia after compression in a vapour compression system is
20 to 50°C
50 to 70°C
70 to 110°C
None of these
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 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)
Which of the following refrigerant has the highest freezing point.
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
The dry bulb temperature lines, on the psychrometric chart are
Vertical and uniformly spaced
Horizontal and uniformly spaced
Horizontal and non-uniformly spaced
Curved lines
During heating and humidification, the final relative humidity of air
Can be lower or higher than that of the entering air
Is lower than that of the entering air
Is higher than that of the entering air
None of the above
Degree of saturation or percentage humidity is
The mass of water vapour present in 1 m³ of dry air
The mass of water vapour present in 1 kg of dry air
The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
During sensible cooling of air ________ decreases.
Wet bulb temperature
Relative humidity
Dry bulb temperature
Specific humidity
Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?
Ammonia
Carbon dioxide
Sulphur dioxide
Fluorine
For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then
Bigger cabinet should be used
Smaller cabinet should be used
Perfectly tight vapour seal should be used
Refrigerant with lower evaporation temperature should be used
The refrigerant widely used in domestic refrigerators is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
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