REFRIGERATION AND AIR CONDITIONING
6th Exam/Mech/5313/
Duration: 3 Hrs. Max.
Marks: 75
Note : Attempt all questions.
Q1 a. State True or False: -
i. A one ton refrigeration system is one that removes 211
Ku Keal of heat per min.
ii. The aircrafts use air refrigeration system for their
air conditioning.
iii. The effect of sub-cooling is to decrease the
refrigerating effect.
iv. Psychrornetric is the study of the properties of air.
v. The refrigerant is a carrier of heat from a high temp.
region to a law temp region.
b. Fill in the blanks: -
i. The COP of a refrigerating mid: is the ratio of__________
to________
ii. A machine having its capacity to produce cooling
effect of_________BTUimt-. ls classed as a one ton machine-
iii. The COP of a refrigerator working cn Bell-Coleman
cycle is by as COP__________
iv. The effect of superheating in vapour compression
refrigeration system! is to_____ COP.
v. The most popular type of refrigerator which employs a
vapour absorption system is the _______refrigerator.
vi. The heat carrying medium used in a refrigeration
system is known as________
vii. The latent heat of a refrigerant should be as______as
possible.
viii. The water vapour present in air is known as___________
ix. A psychrometric chart is a graphical representation
of the various________ properties of moist air.
x. The movement of air to produce a temp. Gradient from
floor to ceiling is known as_________
Q2 Attempt any five questions.
i. What are the methods of refrigeration?
ii. Explain the working of a Bell-Coleman refrigerator.
Drive the equation for its COP.
iii. What is the effect of subvcooling and superheating
the refrigerant in a vapour compression system with diagram?
iv. Draw a neat line diagram of an electroluk refrigerator
and explain its working principle.
v. Define a refrigerant and classify the refrigerants.
vi. What is the function cf a compressor in a
refrigeration system? How compressors are classified?
vii. Esplain the working of a thermostat with diagram. -Ios
Attempt any three questions.
i. Explain the working of a window type air conditioner
by drawing a line sketch.
ii. Define
psychrometry.
150m3 of air per minute at 15°C DBT and 30% RH,
is heated with its temp. is- 22°C. Find
heat added to air per minute R.H. of heated air Wet bulb temperature of heated air Assume air pressure = 1.01325
iii. Describe briefly the factors, which affect human
comfort.
iv. What do you mean by air conditioning? How the air
conditioning systems are classified?
v. Explain the principle of evaporate cooling. Give the
layout of an ice plant.
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