The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is
Same
More
Less
More or less depending on ambient conditions
Correct Answer :
C. Less
Related Questions
The fluids used in Electrolux refrigerator are
Water and hydrogen
Ammonia and hydrogen
Ammonia, water and hydrogen
None of these
The thermostatic expansion valve is used in __________ type of evaporators.
Flooded
DX coil
Dry
None of these
The central air conditioning system has ________ overall efficiency as compared to individual systems.
Same
Lower
Higher
None of these
The moisture in a refrigerant is removed by
Evaporator
Safety relief valve
Dehumidifier
Driers
The wet bulb temperature during sensible cooling of air
Remains constant
Increases
Decreases
None of these
The advantage of dry compression is that
It permits higher speeds to be used
It permits complete evaporation in the evaporator
It results in high volumetric and mechanical efficiency
All of the above
In a vapour compression cycle, the refrigerant immediately after expansion valve is
Liquid
Sub-cooled liquid
Saturated liquid
Wet vapour
The vapour compression refrigerator employs the following cycle
Rankine
Carnot
Reversed Rankine
Reversed Carnot
The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is
Same
More
Less
More or less depending on ambient conditions
Refrigeration in aeroplanes usually employs the following refrigerant
CO2
Freon-11
Freon-22
Air
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
The dry bulb temperature lines, on the psychrometric chart are
Vertical and uniformly spaced
Horizontal and uniformly spaced
Horizontal and non-uniformly spaced
Curved lines
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
A valve which maintains a constant degree of superheat at the end of the evaporator coil, is called
Automatic expansion valve
High side float valve
Thermostatic expansion valve
Low side float valve
The coefficient of performance is the ratio of the refrigerant effect to the
Heat of compression
Work done by compressor
Enthalpy increase in compressor
All of the above
The Freon group of refrigerants are
Halocarbon refrigerants
Zoetrope refrigerants
Inorganic refrigerants
Hydrocarbon refrigerants
R-12 is generally preferred over R-22 in deep freezers since
It has low operating pressures
It gives higher coefficient of performance
It is miscible with oil over large range of temperatures
All of the above
In a domestic refrigerator, a capillary tube controls the flow of refrigerant from the
Expansion valve to the evaporator
Evaporator to the thermostat
Condenser to the expansion valve
Condenser to the evaporator
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
Absorption system normally uses the following refrigerant
Freon-11
Freon-22
CO2
Ammonia
The relative humidity is defined as
The mass of water vapour present in 1 m3 of dry air
The mass of water vapour present in 1 kg of dry air
The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
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
The boiling point of carbon dioxide is
-20.5°C
-50°C
-63.3°C
-78.3°C
In larger industrial and commercial reciprocating compression systems, refrigerant widely used is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
A standard ice point temperature corresponds to the temperature of
Water at 0°C
Ice at 4°C
Solid and dry ice
Mixture of ice and water under equilibrium conditions
Presence of moisture in a refrigerant affects the working of
Compressor
Condenser
Evaporator
Expansion valve
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
Formation of frost on evaporator in refrigerator
Results in loss of heat due to poor heat transfer
Increases heat transfer rate
Is immaterial
Can be avoided by proper design
In a vapour compression refrigeration system, a throttle valve is used in place of an expander because
It considerably reduces mass of the system
It improves the C.O.P., as the condenser is small
The positive work in isentropic expansion of liquid is very small
It leads to significant cost reduction
During dehumidification process, the relative humidity
Remains constant
Increases
Decreases
None of these
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