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Refrigeration and Air Conditioning 4-1 Set-4 (K).doc (Size: 346 KB / Downloads: 6)
What are the desirable characteristics of a Refrigerant-Absorbent pair. [6] (Unit-III, Topic No. 3.5)
With the help of T-S and P-H charts explain the working of air refrigeration system working on Bell Colemann
cycle. [9] (Unit-I, Topic No. 1.3)
Evaluate the performance of a simple vapour compression refrigeration cycle taking into account the effect of
suction and delivery pressure. [8] (Unit-II, Topic No. 2.3)
In an ammonia vapour compression refrigerator, the temperature of refrigerator is –10°C. The vapour is condensed
in a condenser at 30°C. Find the theoretical C.O.P of the cycle when the vapour at the end of compression is 0.9
dry. Take latent heat of NH3 AT 30°C= 1442 kJ/kg, specific heat of liquid NH3 = 4.7 kJ/kg.[7] (Unit-II, Topic No. 2.3)
List out the advantages and disadvantages of air cooled condensers and water cooled condensers. [8]
(Unit-III, Topic No. 3.2)
Explain the role of CO2 and CFCs in green house effect. [7] (Unit-III, Topic No. 3.2)
With a neat sketch explain the working of Li - Br vapour absorption refrigeration system. [8] (Unit-IV, Topic No. 4.2)
Write the advantages of absorption refrigeration system over compression refrigeration system. [7]
(Unit-IV, Topic No. 4.1)
Explain with the help of graphs the effect of evaporator temperature and supply steam pressure on the
consumption of steam required per ton of refrigeration and give the causes. [8] (Unit-V, Topic No. 5.1)
With the help of a neat sketch explain the working of a steam ejector. [7] (Unit-V, Topic No. 5.1)
Atmospheric air at 101.3 kPa, 22°C, 65 percent relative humidity, is to be used to cool a transformer. The
transformer dissipates heat at a rate of 230 MJ/h. To increase the cooling effect per kilogram of dry air and
thereby decrease the amount of air needed, the air is first adiabatically saturated with water and then passed
over the transformer. If the temperature of the air leaving the transformer should not exceed 32°C, determine the
required flow rate in kilograms of dry air per hour both with and without the adiabatic saturation of the
incoming air.[10] (Unit-VI, Topic No. 6.1)
What are the factors to be considered for load estimation for air conditioning? [5] (Unit-VII, Topic No. 7.2)
Explain the requirements of comfort air conditioning. [5] (Unit-VII, Topic No. 7.1)
Define the term ‘bypass’ factor used for cooling or heating coil and find the expression for that. [10]
(Unit-VI, Topic No. 6.2)
With a neat sketch explain about year round air conditioning system. [8] (Unit-VIII, Topic No. 8.1)
An ejector refrigeration unit is to be designed to deliver 150 kg per minute of chilled water at 4° C from supply
water at 22°C. Water vapour entering the ejector has a quality of 0.97. Determine: