For air conditioning the operation theatre in a hospital, the percentage of outside air in the air supplied is
Zero
20
50
100
Correct Answer :
D. 100
Related Questions
A one tonne refrigerating machine means that
One tonne is the total mass of machine
One tonne refrigerant is used
One tonne of water can be converted into ice
One tonne of ice when melts from and at 0° C in 24 hours, the refrigeration effect is equivalent to 210 kJ/min
Which of the following refrigerants has lowest freezing point?
Freon-12
NH3
CO2
Freon-22
Short horizontal lines on pressure-enthalpy chart show
Constant pressure lines
Constant temperature lines
Constant total heat lines
Constant entropy lines
Freon group of refrigerants are
Inflammable
Toxic
Non-inflammable and toxic
Nontoxic and non-inflammable
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
Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?
Ammonia
Carbon dioxide
Sulphur dioxide
Fluorine
The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, will
Increase
Decrease
May increase or decrease depending on the type of refrigerant used
Remain unaffected
One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice
In 1 hour
In 1 minute
In 24 hours
In 12 hours
Dry bulb temperature is the temperature of air recorded by a thermometer, when
It is not affected by the moisture present in the air
Its bulb is surrounded by a wet cloth exposed to the air
The moisture present in it begins to condense
None of the above
A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be
1/4
1/3
3
4
For obtaining high COP, the pressure range of compressor should be
High
Low
Optimum
Any value
If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be
Same
More
Less
More/less depending on rating
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
Superheating in a refrigeration cycle
Increases C.O.P
Decreases C.O.P
C.O.P remains unaltered
Other factors decide C.O.P
The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is
Bigger
Smaller
Equal
Smaller/bigger depending on capacity
In a reversed Brayton cycle, the heat is absorbed by the air during
Isentropic compression process
Constant pressure cooling process
Isentropic expansion process
Constant pressure expansion process
The vapour compression refrigerator employs the following cycle
Rankine
Carnot
Reversed Rankine
Reversed Carnot
Moisture in Freon refrigeration system causes
Ineffective refrigeration
High power consumption
Freezing automatic regulating valve
Corrosion of whole system
A vapour absorption refrigeration system
Gives noisy operation
Gives quiet operation
Requires little power consumption
Cools below 0°C
During sensible cooling of air ________ decreases.
Wet bulb temperature
Relative humidity
Dry bulb temperature
Specific humidity
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 wet bulb temperature during sensible cooling of air
Remains constant
Increases
Decreases
None of these
In vapour compression cycle the condition of refrigerant is superheated vapour
After passing through the condenser
Before passing through the condenser
After passing through the expansion or throttle valve
Before entering the expansion valve
Which of the following cycles uses air as the refrigerant?
Ericson
Stirling
Carnot
Bell Coleman
A mixture of dry air and water vapour, when the air has diffused the maximum amount of water vapour into it, is called
Dry air
Moist air
Saturated air
Specific humidity
The formation of frost on cooling coils in a refrigerator
Increases heat transfer
Improves C.O.P. of the system
Increases power consumption
Reduces power consumption
The bank of tubes at the back of domestic refrigerator is
Condenser tubes
Evaporator tubes
Refrigerant cooling tubes
Capillary tubes
The human body feels comfortable when the heat stored in the body is
Positive
Negative
Zero
None of these
If a gas is to be liquefied, its temperature must be
Increased to a value above its critical temperature
Reduced to a value below its critical temperature
Equal to critical temperature
None of the above
A bootstrap air cooling system has
One heat exchanger
Two heat exchangers
Three heat exchangers
Four heat exchangers