Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 8th Sem Old 181901 Refrigeration And Air Conditioning Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VIII (OLD) EXAMINATION ? WINTER 2018
Subject Code: 181901 Date: 26/11/2018
Subject Name: Refrigeration And Air-Conditioning
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain steam jet refrigeration system with neat sketch. 07
(b) Explain Boot strap air refrigeration system with neat sketch. 07
Q.2 (a) Explain the following terms.
1) Refrigeration effect 2) Dew point temperature
3) Comfort air conditioning 4) Cooling and Dehumidification
5) Wet bulb temperature 6) Psychrometry
7) Relative humidity.
07
(b) The pressure and temperature of mixture of dry air and water vapour are 740 mm
of mercury and 20
o
C. The dew point temperature is 14
o
C. Calculate (1) Partial
pressure of water vapour in the mixture, (2) Relative humidity (3) Specific
humidity (4) Specific volume of mixture per kg of dry air and (5) Enthalpy of
mixture per kg of dry air.
07
OR
(b) Explain working of Li-Br vapour absorption refrigeration system with neat
sketch.
07
Q.3 (a) State and explain various heat loads to be considered for cooling load calculations
of a typical building.
07
(b) What are the different methods are used for a design of the duct and explain
advantages of each other.
07
OR
Q.3 (a) Explain with neat sketch various terms used in air distribution. 07
(b) A comfort air conditioning system is to be design for following information :
Outside air condition 30
o
C DBT, 24
o
C WBT
Inside air condition 20
o
C DBT, 50% RH
Air required in room 50 m
3
/min
The comfort condition are achieved first by dehumidification and then cooling
the air. Determine: (i) mass of water condensed and (ii) capacity of cooling coil.
07
Q.4 (a) State main application of refrigeration and explain Ice making plant with suitable
diagram.
07
(b) Write short note on: 1) Shell and tube condenser and 2) Screw compressor. 07
OR
Q.4 (a) Explain multistage refrigeration system with intercooling between stages. 07
(b) A refrigerator working on bell-Coleman cycle takes air in to compressor at 1 bar
and -5
o
C. It is compress in compressor to a 5 bar and cooled to 25
o
C at the same
pressure. It is further expanded in the expander to 1 bar discharged to take cooling
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VIII (OLD) EXAMINATION ? WINTER 2018
Subject Code: 181901 Date: 26/11/2018
Subject Name: Refrigeration And Air-Conditioning
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain steam jet refrigeration system with neat sketch. 07
(b) Explain Boot strap air refrigeration system with neat sketch. 07
Q.2 (a) Explain the following terms.
1) Refrigeration effect 2) Dew point temperature
3) Comfort air conditioning 4) Cooling and Dehumidification
5) Wet bulb temperature 6) Psychrometry
7) Relative humidity.
07
(b) The pressure and temperature of mixture of dry air and water vapour are 740 mm
of mercury and 20
o
C. The dew point temperature is 14
o
C. Calculate (1) Partial
pressure of water vapour in the mixture, (2) Relative humidity (3) Specific
humidity (4) Specific volume of mixture per kg of dry air and (5) Enthalpy of
mixture per kg of dry air.
07
OR
(b) Explain working of Li-Br vapour absorption refrigeration system with neat
sketch.
07
Q.3 (a) State and explain various heat loads to be considered for cooling load calculations
of a typical building.
07
(b) What are the different methods are used for a design of the duct and explain
advantages of each other.
07
OR
Q.3 (a) Explain with neat sketch various terms used in air distribution. 07
(b) A comfort air conditioning system is to be design for following information :
Outside air condition 30
o
C DBT, 24
o
C WBT
Inside air condition 20
o
C DBT, 50% RH
Air required in room 50 m
3
/min
The comfort condition are achieved first by dehumidification and then cooling
the air. Determine: (i) mass of water condensed and (ii) capacity of cooling coil.
07
Q.4 (a) State main application of refrigeration and explain Ice making plant with suitable
diagram.
07
(b) Write short note on: 1) Shell and tube condenser and 2) Screw compressor. 07
OR
Q.4 (a) Explain multistage refrigeration system with intercooling between stages. 07
(b) A refrigerator working on bell-Coleman cycle takes air in to compressor at 1 bar
and -5
o
C. It is compress in compressor to a 5 bar and cooled to 25
o
C at the same
pressure. It is further expanded in the expander to 1 bar discharged to take cooling
07
2
load. The isentropic efficiency of the compressor = 85% and the isentropic
efficiency of expander = 90%. Find the following.
1. Refrigerating capacity of system if air circulation is 40 kg/min.
2. KW capacity of motor required to run the compressor.
3. COP of system.
Q.5 (a) Explain construction and working of simple vapour compression refrigeration
system with P-V, T-S and P-H diagram.
07
(b) Explain with neat sketch year round air conditioning system. 07
OR
Q.5 (a) What are the desirable properties of ideal refrigerant? Explain how refrigerant
are designed.
07
(b) Explain with neat sketch Electrolux refrigerator. 07
*************
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This post was last modified on 20 February 2020