Question Paper: Refrigeration And Airconditioning : Question Paper May 2016 - Mechanical Engineering (Semester 8) | Gujarat Technological University (GTU)
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## Refrigeration And Airconditioning - May 2016

### Mechanical Engineering (Semester 8)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) Describe a simple vapour compression cycle giving clearly its flow and T-s diagram(7 marks) 1 (b) Give the full name of the following refrigerants:
R-12, R717,R-22,R-134a,R-600,R-150,R-123
(7 marks)
2 (a) Sketch bootstrap air cycle refrigeration cycle and derive an expression for its COP.(7 marks)

### Solve any one question from Q2(b) & Q2(c)

2 (b) Compare between water cooled and air cooled condensers. Explain evaporative condenser.(7 marks) 2 (c) What are the advantages and disadvantages of steam jet refrigeration system over other type of system? Explain its working principle.(7 marks)

### Solve any two question from Q3(a), Q3(b) & Q3(c), Q3(d)

3 (a) (i) Write Short Note: Shell and tube condenser(3 marks) 3 (a) (ii) Write Short Note:Screw compressor(4 marks) 3 (b) With a diagram explain Li-BR Vapor absorption refrigeration system and write its application.(7 marks) 3 (b) The pressure and temperature of mixture of dry air and water vapor are 736mm of Hg and 21 C.The dew point temperature of the mixture is 15 C. Determine the following using steam table:1) Mixture (2) Relative humidity (3) Specific humidity (4) Enthalpy of mixture per Kg of dry air (5) specific volume of mixture per kg of dry air.(7 marks) 3 (c) Explain the following terms:1.Dry bulb temperature 2.specific humidity 3.Relative humidity 4.Thermodynamic wet bulb temperature 5.Dew point temperature 6.Degree of saturation 7.Adiabatic saturation Temperature(7 marks)

### Solve any two question from Q4(a), Q4(b) & Q4(c), Q4(d)

4 (a) Explain infiltration of air. What point should be considered while making heat load calculation?(7 marks) 4 (b) An office for seating 30 occupants is to be maintained at 22 C DBT and 55% RH.The outdoor conditions are 36 C DBT and 27 C WBT.The various loads in the office are
1)solar heat gain:8500W
2)sensible heat gain per occupants:83 W
3)Latent heat gain peroccupant:100W
5)Sensible heat load from other sources:12000W