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
Correct Answer :
A. Increases with increase in velocity of air passing through it
Related Questions
The unit of thermal diffusivity is
m/hK
m/h
m²/h
m²/hK
The capillary tube, as an expansion device, is used in
Domestic refrigerators
Water coolers
Room air conditioners
All 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
In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature
Which lies between the dry bulb and wet bulb temperatures of the incoming stream
Which lies between the wet bulb and dew point temperatures of the incoming stream
Which is lower than the dew point temperature of the incoming stream
Of adiabatic saturation of incoming stream
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
Air refrigerator works on
Reversed Carnot cycle
Bell Coleman cycle
Both (A) and (B)
None of these
Carbon dioxide is
Colourless
Odourless
Non-flammable
All of these
Which of the following cycles uses air as the refrigerant?
Ericson
Stirling
Carnot
Bell Coleman
Most air cooled condensers are designed to operate with a temperature difference of
5°C
8°C
14°C
22°C
In chemical dehumidification process,
Dew point temperature decreases
Wet bulb temperature decreases
Dry bulb temperature increases
All of these
The conditioned air supplied to the room must have the capacity to take up
Room sensible heat load only
Room latent heat load only
Both room sensible heat and latent heat loads
None of the above
The bypass factor, in case of sensible cooling of air, is given by (where td₁ = Dry bulb temperature of air entering the cooling coil, td₂ = Dry bulb temperature of air leaving the cooling coil, and td₃ = Dry bulb temperature of the cooling coil)
(td₁ -td₃)/( td₂ -td₃)
(td₂ -td₃)/( td₁ -td₃)
(td₃ -td₁)/( td₂ -td₃)
(td₃ -td₂)/( td₁ -td₃)
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
In a lithium bromide absorption refrigeration system
Lithium bromide is used as a refrigerant and water as an absorbent
Water is used as a refrigerant and lithium bromide as an absorbent
Ammonia is used as a refrigerant and lithium bromide as an absorbent
None of the above
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
During sensible cooling,
Relative humidity remains constant
Wet bulb temperature increases
Specific humidity increases
Partial pressure of vapour remains constant
The relative coefficient of performance is equal to
(Theoretical C.O.P.)/ (Actual C.O.P.)
(Actual C.O.P.) /(Theoretical C.O.P.)
(Actual C.O.P.) × (Theoretical C.O.P.)
None of these
The moisture in a refrigerant is removed by
Evaporator
Safety relief valve
Dehumidifier
Driers
The alignment circle is marked on the psychrometric chart at
20°C DBT and 50% RH
26°C DBT and 50% RH
20°C DBT and 60% RH
26°C DBT and 60% RH
In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by
Liquid pump
Generator
Absorber and generator
Absorber, generator and liquid pump
During humidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
For obtaining high COP, the pressure range of compressor should be
High
Low
Optimum
Any value
Which of the following statement is wrong?
The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.
In vapour compression cycle, the useful part of the heat transfer is at the condenser.
In ammonia-hydrogen (Electrolux) refrigerator, no compressor, pump or fan is required.
The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance.
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
Which of the following refrigerants has lowest freezing point?
Freon-12
NH3
CO2
Freon-22
The vapour compression refrigerator employs the following cycle
Rankine
Carnot
Reversed Rankine
Reversed Carnot
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)
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
The specific humidity during humidification process
Remains constant
Increases
Decreases
None of these
Moisture in Freon refrigeration system causes
Ineffective refrigeration
High power consumption
Freezing automatic regulating valve
Corrosion of whole system