The central air conditioning system has ________ overall efficiency as compared to individual systems.
Same
Lower
Higher
None of these
Correct Answer :
C. Higher
Related Questions
The refrigerant supplied to a compressor must be
Superheated vapour refrigerant
Dry saturated liquid refrigerant
A mixture of liquid and vapour refrigerant
None of these
One tonne of refrigeration (1TR) means that the heat removing capacity is
21 kJ/min
210 kJ/min
420 kJ/min
620 kJ/min
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, is called
Humidity ratio
Relative humidity
Absolute humidity
Degree of saturation
The fluids used in Electrolux refrigerator are
Water and hydrogen
Ammonia and hydrogen
Ammonia, water and hydrogen
None of these
The index which correlates the combined effects of air temperature, relative humidity and air velocity on the human body, is known as
Mean radiant temperature
Effective temperature
Dew point temperature
None of these
During humidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
A vapour absorption refrigerator uses __________ as a refrigerant.
Water
Ammonia
Freon
Aqua-ammonia
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 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
In a vapour compression cycle, the refrigerant immediately after expansion valve is
Liquid
Sub-cooled liquid
Saturated liquid
Wet vapour
In a domestic refrigerator, a capillary tube controls the flow of refrigerant from the
Expansion valve to the evaporator
Evaporator to the thermostat
Condenser to the expansion valve
Condenser to the evaporator
The thermostatic expansion valve is used in __________ type of evaporators.
Flooded
DX coil
Dry
None of these
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
While designing the refrigeration system of an aircraft, the prime consideration is that the
System has high C.O.P.
Power per TR is low
Mass of refrigerant circulated in the system is low
Mass of the refrigeration equipment is low
Accumulators should have adequate volume to store refrigerant charge at least
10 %
25 %
50 %
75 %
One ton of the refrigeration is
The standard unit used in refrigeration problems
The cooling effect produced by melting 1 ton of ice
The refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours
The refrigeration effect to produce 1 ton of ice at NTP conditions
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 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
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
Condensing temperature in a refrigerator is the temperature
Of cooling medium
Of freezing zone
Of evaporator
At which refrigerant gas becomes liquid
Which of the following refrigerant has the lowest freezing point?
R-11
R-12
R-22
Ammonia
Most thermostatic expansion valves are set for a superheat of
5°C
10°C
15°C
20°C
In a refrigeration system, the expansion device is connected between the
Compressor and condenser
Condenser and receiver
Receiver and evaporator
Evaporator and compressor
Moisture should be removed from refrigerants to avoid
Freezing at the expansion valve
Restriction to refrigerant flow
Corrosion of steel plates
All of these
Allowable pressure on high pressure side or ammonia absorption system is of the order of
Atmospheric pressure
Slightly above atmospheric pressure
24 bars
56 bars
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
In Electrolux refrigerator
Ammonia is absorbed in hydrogen
Ammonia is absorbed in water
Ammonia evaporates in hydrogen
Hydrogen evaporates in ammonia
A bootstrap air cooling system has
One heat exchanger
Two heat exchangers
Three heat exchangers
Four heat exchangers
Air refrigeration operates on
Carnot cycle
Reversed Carnot cycle
Rankines cycle
Brayton cycle
Where does the lowest temperature occur in a vapour compression cycle?
Condenser
Evaporator
Compressor
Expansion valve