One tonne of refrigeration (1TR) means that the heat removing capacity is
21 kJ/min
210 kJ/min
420 kJ/min
620 kJ/min
Correct Answer :
B. 210 kJ/min
Related Questions
The mass of water vapour present in __________ is called absolute humidity.
1 m3 of water
1 m3 of dry air
1 kg of wet air
1 kg of dry air
Presence of moisture in a refrigerant affects the working of
Compressor
Condenser
Evaporator
Expansion valve
The comfort conditions in air conditioning are at (where DBT = Dry bulb temperature, and RH = Relative humidity)
25°C DBT and 100% RH
20°C DBT and 80% RH
22°C DBT and 60% RH
25°C DBT and 40% RH
Absorption system normally uses the following refrigerant
Freon-11
Freon-22
CO2
Ammonia
The power per tonne of refrigeration is
3.5/C.O.P.
C.O.P/3.5
3.5 × C.O.P.
None of these
Environmental protection agencies advice against the use of chlorofluorocarbon refrigerants since
These react with water vapour and cause acid rain
These react with plants and cause greenhouse effect
These react with oxygen and cause its depletion
These react with ozone layer
For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of
Copper
Aluminium
Steel
Brass
In a vapour compression cycle, the refrigerant immediately after expansion valve is
Liquid
Sub-cooled liquid
Saturated liquid
Wet vapour
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
In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = Bypass factor)
B.P.F. - 1
1 - B. P.F.
1/ B.P.F.
1 + B.P.F.
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
Chaperon equation is a relation between
Temperature, pressure and enthalpy
Specific volume and enthalpy
Temperature and enthalpy
Temperature, pressure, specific volume and enthalpy
The bypass factor of a cooling coil decreases with
Decrease in fin spacing and increase in number of rows
Increase in fin spacing and increase in number of rows
Increase in fin spacing and decrease in number of rows
Decrease in fin spacing and decrease in number of rows
In mechanical refrigeration system, the refrigerant has the maximum temperature
In evaporator
Before expansion valve
Between compressor and condenser
Between condenser and evaporator
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 C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will
Increase
Decrease
Remain unaffected
May increase or decrease depending on the type of refrigerant used
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)
The coefficient of performance of a domestic refrigerator is ________ as compared to a domestic air-conditioner.
Same
Less
More
None of these
The evaporator used in household refrigerators is
Frosting evaporator
Non-frosting evaporator
Defrosting evaporator
None of these
The central air conditioning system has ________ overall efficiency as compared to individual systems.
Same
Lower
Higher
None of these
The thermal diffusivity for gases is generally __________ those for liquids.
Equal to
Less than
Greater than
None of these
During sensible cooling of air, specific humidity
Remains constant
Increases
Decreases
None of these
The air cooling system mostly used in transport type aircrafts is
Simple air cooling system
Simple evaporative air cooling system
Bootstrap air cooling system
All of these
For large tonnage (more than 200 TR) air-conditioning applications, the compressor recommended is
Reciprocating
Rotating
Centrifugal
Screw
The thermostatic expansion valve is used in __________ type of evaporators.
Flooded
DX coil
Dry
None of these
An evaporator is also known as
Freezing coil
Cooling coil
Chilling coil
All of these
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
Air refrigeration cycle is used in
Domestic refrigerators
Commercial refrigerators
Air conditioning
Gas liquefaction
The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases,
Will be higher
Will be lower
Will remain unaffected
May be higher or lower depending upon the nature of noncondensable gases
When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be
Cooled and humidified
Cooled and dehumidified
Heated and humidified
Heated and dehumidified