The process, generally used in winter air-conditioning to warm and humidity the air, is called
Humidification
Dehumidification
Heating and humidification
Cooling and dehumidification
Correct Answer :
C. Heating and humidification
Related Questions
In Electrolux refrigerator
Ammonia is absorbed in hydrogen
Ammonia is absorbed in water
Ammonia evaporates in hydrogen
Hydrogen evaporates in ammonia
Rating of a domestic refrigerator is of the order of
0.1 ton
5 tons
10 tons
40 tons
A vapour absorption refrigeration system
Gives noisy operation
Gives quiet operation
Requires little power consumption
Cools below 0°C
The vertical and uniformly spaced lines on a psychrometric chart indicates
Dry bulb temperature
Wet bulb temperature
Dew point temperature
Specific humidity
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
The humidity ratio or specific humidity is the mass of water vapour present in
1 m3 of wet air
1 m3 of dry air
1 kg of wet air
1 kg of dry air
During cooling and dehumidification, dry bulb temperature
Remains constant
Increases
Decreases
None of these
During humidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
A human body feels comfortable when the heat produced by the metabolism of human body is equal to the
Heat dissipated to the surroundings
Heat stored in the human body
Sum of (A) and (B)
Difference of (A) and (B)
One of the purposes of sub cooling the liquid refrigerant is to
Reduce compressor overheating
Reduce compressor discharge temperature
Increase cooling effect
Ensure that only liquid and not the vapour enters the expansion (throttling) valve
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
Critical pressure of a liquid is the pressure
Above which liquid will remain liquid
Above which liquid becomes gas
Above which liquid becomes vapour
Above which liquid becomes solid
In a refrigerating machine, heat rejected is _________ heat absorbed.
Equal to
Less than
Greater than
None of these
The wet bulb temperature during sensible heating of air
Remains constant
Increases
Decreases
None of these
Condensing temperature in a refrigerator is the temperature
Of cooling medium
Of freezing zone
Of evaporator
At which refrigerant gas becomes liquid
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 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
In which of the following refrigeration system, waste heat can be effectively used?
Vapour compression cycle
Vapour absorption cycle
Air refrigeration cycle
None of these
Short horizontal lines on pressure-enthalpy chart show
Constant pressure lines
Constant temperature lines
Constant total heat lines
Constant entropy lines
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
A refrigerant compressor is used to
Raise the pressure of the refrigerant
Raise the temperature of the refrigerant
Circulate the refrigerant through the refrigerating system
All of the above
Efficiency of a Carnot engine is given as 80%. If the cycle direction be reversed, what will be the value of COP of reversed Carnot Cycle?
1.25
0.8
0.5
0.25
The bypass factor for a cooling coil
Increases with increase in velocity of air passing through it
Decreases with increase in velocity of air passing through it
Remains unchanged with increase in velocity of air passing through it
May increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering
The boiling point of ________ is 10.5°C.
Ammonia
R-12
Sulphur dioxide
Carbon dioxide
In chemical dehumidification process,
Dew point temperature decreases
Wet bulb temperature decreases
Dry bulb temperature increases
All of these
During sensible cooling,
Relative humidity remains constant
Wet bulb temperature increases
Specific humidity increases
Partial pressure of vapour remains constant
In aqua ammonia absorption refrigeration system, incomplete rectification leads to accumulation of water in
Condenser
Evaporator
Absorber
None of these
A good refrigerant should have
High latent heat of vaporisation and low freezing point
High operating pressures and low freezing point
High specific volume and high latent heat of vaporisation
Low C.O.P. and low freezing point
The emissivity of a polished silver body is __________ as compared to black body.
Same
Low
Very low
High
Air refrigerator works on
Reversed Carnot cycle
Bell Coleman cycle
Both (A) and (B)
None of these