In a vapour compression system, the condition of refrigerant before passing through the condenser is
Saturated liquid
Wet vapour
Dry saturated vapour
Superheated vapour
Correct Answer :
D. Superheated vapour
Related Questions
The specific humidity during cooling and dehumidification
Remains constant
Increases
Decreases
None of these
In order to collect liquid refrigerant and to prevent it from going to a ________, a device known as accumulator is used at the suction of compressor.
Compressor
Condenser
Expansion valve
Evaporator
The capillary tube is not used in large capacity refrigeration systems because
Cost is too high
Capacity control is not possible
It is made of copper
Required pressure drop cannot be achieved
A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67 kg/cm. The refrigerant used is
Ammonia
Carbon dioxide
Freon
Brine
Ammonia absorption refrigeration cycle requires
Very little work input
Maximum work input
Nearly same work input as for vapour compression cycle
Zero work input
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
Air refrigerator works on
Reversed Carnot cycle
Bell Coleman cycle
Both (A) and (B)
None of these
In vapour compression cycle, the condition of refrigerant is saturated liquid
After passing through the condenser
Before passing through the condenser
After passing through the expansion throttle valve
Before entering the expansion valve
The refrigerant after condensation process is cooled below the saturation temperature before throttling. Such a process is called
Sub-cooling or under-cooling
Super-cooling
Normal cooling
None of these
An infinite parallel planes with emissivities e₁ and e₂, the interchange factor for radiation from surface 1 to surface 2 is given by
(e₁ + e₂)/ e₁ + e₂ - e₁e₂
1/e₁ + 1/e₂
e₁ + e₂
e₁e₂
One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice
In 1 hour
In 1 minute
In 24 hours
In 12 hours
The refrigerant used in small tonnage commercial machines (hermetically sealed units) is
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be
1/4
1/3
3
4
Freon group of refrigerants are
Inflammable
Toxic
Non-inflammable and toxic
Nontoxic and non-inflammable
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
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 suction pipe diameter of refrigerating unit compressor in comparison to delivery side is
Bigger
Smaller
Equal
Smaller/bigger depending on capacity
Oil separator in a refrigeration cycle is installed
Before compressor
Between compressor and condenser
Between condenser and evaporator
Between condenser and expansion valve
In vapour compression cycle the condition off refrigerant is dry saturated vapour
After passing through the condenser
Before passing through the condenser
After passing through the expansion or throttle valve
Before entering the compressor
During heating and dehumidification process, dry bulb temperature
Remains constant
Increases
Decreases
None of these
The process, generally used in summer air conditioning to cool and dehumidify the air, is called
Humidification
Dehumidification
Heating and humidification
Cooling and dehumidification
The index which correlates the combined effects of air temperature, relative humidity and air velocity on the human body, is known as
Mean radiant temperature
Effective temperature
Dew point temperature
None of these
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
In a vapour compression system, the condition of refrigerant before passing through the condenser is
Saturated liquid
Wet vapour
Dry saturated vapour
Superheated vapour
The thermostatic expansion valve is used in __________ type of evaporators.
Flooded
DX coil
Dry
None of these
The thermostatic expansion valve is also called
Constant pressure valve
Constant temperature valve
Constant superheat valve
None 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
The evolution of heat of solution takes place in ammonia absorption plant when
Ammonia vapour goes into solution
Ammonia vapour is driven out of solution
Lithium bromide mixes with ammonia
Weak solution mixes with strong solution
Which of the following statement is correct for ammonia as a refrigerant?
It is toxic to mucous membranes.
It requires large displacement per TR compared to fluoro carbons.
It reacts with copper and its alloys.
All of these
Which of the following statement is correct?
In vapour absorption refrigerator, the compression of refrigerant is avoided.
Sub-cooling can be achieved by circulating more quantity of cooling water through the condenser.
In vapour compression refrigeration, the vapour is drawn in the compressor cylinder during its suction stroke and is compressed adiabatically during the compression stroke.
All of the above