The thermostatic expansion valve is also called
Constant pressure valve
Constant temperature valve
Constant superheat valve
None of these
Correct Answer :
C. Constant superheat valve
Related Questions
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
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
A refrigerant with the highest critical pressure is
R-11
R-12
R-22
Ammonia
Air conditioning means
Cooling
Heating
Dehumidifying
All of these
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
The wet bulb temperature at 100% relative humidity is ________ dry bulb temperature.
Same as
Lower than
Higher than
None of these
Highest pressure encountered in a refrigeration system should be
Critical pressure of refrigerant
Much below critical pressure
Much above critical pressure
Near critical pressure
The refrigerant used in small tonnage commercial machines (hermetically sealed units) is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
The wet bulb temperature at 100% relative humidity is ________ dew point temperature.
Same as
Lower than
Higher than
None of these
In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is
Less than 2 kg
More than or equal to 3.65 kg
More than 10 kg
There is no such consideration
For unsaturated air, the dew point temperature is __________ wet bulb temperature.
Equal to
Less than
More than
None of these
The superheating in a refrigeration cycle
Does not alter C.O.P.
Increases C.O.P.
Decreases C.O.P.
None of these
During cooling and dehumidification, dry bulb temperature
Remains constant
Increases
Decreases
None of these
For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then
Bigger cabinet should be used
Smaller cabinet should be used
Perfectly tight vapour seal should be used
Refrigerant with lower evaporation temperature should be used
The boiling point of ________ is 10.5°C.
Ammonia
R-12
Sulphur dioxide
Carbon dioxide
In aircraft, air refrigeration Cycle is used because of
Low weight per tonne of refrigeration
High heat transfer rate
Low temperature at high altitudes
Higher coefficient of performance
The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy diagram represents
Condensation of the refrigerant vapour
Evaporation of the refrigerant liquid
Compression of the refrigerant vapour
Metering of the refrigerant liquid
The C.O.P. of a refrigerator working on a reversed Carnot cycle is (where T₁ = Lowest absolute temperature, and T₂ = Highest absolute temperature)
T₁ / (T₂ - T₁)
(T₂ - T₁)/T₁
(T₁ - T₂)/T₁
T₂/ (T₂ - T₁)
Accumulators should have adequate volume to store refrigerant charge at least
10 %
25 %
50 %
75 %
A bootstrap air cooling system has
One heat exchanger
Two heat exchangers
Three heat exchangers
Four heat exchangers
The lowest temperature during the cycle in a vapour compression system occurs after
Compression
Expansion
Condensation
Evaporation
In a saturated air-water vapour mixture, the
Dry bulb temperature is higher than wet bulb temperature
Dew point temperature is lower than wet bulb temperature
Dry bulb, wet bulb and dew point temperature are same
Dry bulb temperature is higher than dew point temperature
The refrigerant for a refrigerator should have
High sensible heat
High total heat
High latent heat
Low latent heat
A vapour absorption refrigerator uses __________ as a refrigerant.
Water
Ammonia
Freon
Aqua-ammonia
The operating pressure for refrigerating units using R-12 as a refrigerant is
2 bar
8 bar
15 bar
30 bar
The leaks in a refrigeration system using Freon are detected by
Halide torch which on detection produces greenish flame lighting
Sulphur sticks which on detection gives white smoke
Using reagents
Smelling
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
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
Ammonia is
Non-toxic
Non-inflammable
Toxic and non-inflammable
Highly toxic and inflammable
Carbon dioxide is
Colourless
Odourless
Non-flammable
All of these