21
49
83
ED
E1
90
B2
66
CB
C0
5
16
B2
56
CB
A5
C0
14
6C
25
A3
7
1
9
2
6
A3
83
ED
4
02
E
5
E
7
9
8
ED
11
2E
90
E
58
E
3
5
1
2
90
B2
66
CB
A5
39
5
1
E
B
6
CB
A5
C0
14
0C
6
67
2
A3
C
14
9E
25
67
A3
ED
BA
0
E2
9E
25
83
ED
11
E2
5B
EA
3E
8
1
9
6
39
5B
16
EA
0C
6C
21
2E
56
0C
6C
21
BA
49
02
56
A5
7E
B
4
0
E1
58
7E
9
2
3
D5
67
A
E
5
E
39
16
3
D
8
ED
1
2
B2
E
3
5
1
EA
0C
6C
2
9
B
6
5B
14
E
0
6
21
BA
02
56
CB
A5
C0
9E
21
4
5
7
9E
25
3E
67
A3
83
ED
11
49
83
ED
11
2E
90
66
E1
E
5
2E
90
B2
66
CB
A5
C0
5
16
B2
CB
A5
C0
14
6C
25
67
A3
1
9
2
6
A3
83
ED
4
E
5
E
7
9
8
E
11
2E
90
E1
E2
39
5B
D5
66
CB
A5
16
E
0
2
B
C
A5
C0
14
6C
67
2
A3
B
1
9E
25
67
A3
ED
4
02
E2
9E
83
ED
11
58
E2
5B
EA
1
9
6
5B
16
EA
0C
6C
21
56
6C
21
BA
49
02
56
7E
4
02
E1
58
7
9
3
D5
ED
E
58
E
3
1
1
2
90
B2
66
39
5
1
E
B
6
CB
A5
C0
14
0C
6
2
C
14
9E
25
67
A3
0
9E
25
83
ED
11
E2
83
11
90
66
5
E
90
B2
66
CB
A5
C0
CB
C0
14
25
67
A3
9E
25
A3
83
ED
E
83
11
2E
90
5
90
B2
66
CB
A5
CB
C0
14
67
A3
9
2
A3
E
E1
58
E2
D5
E2
3
1
EA
90
B2
66
EA
56
C
C
1
BA
49
02
7E
E1
58
3E
D5
39
1
2E
B2
66
0
Paper / Subject Code: 89423 / Heating, Ventilation, Air Conditioning and Refrigeration
1T01436 - T.E.(Mechanical) Engineering)(SEM-VI)(Choice Base Credit Grading System ) ((R-20-21) (C Scheme) / 89423 - Heating,
Ventilation, Air Conditioning and Refrigeration
QP CODE: 10015040
DATE: 13/12/2022
(3 Hours)
[Total Marks 80]
Note:
1) Question no. 1 is compulsory.
2) Attempt any three questions out of the remaining five questions.
3) Clearly mention the assumptions made if any.
4) Use of Refrigerant table, P-h chart, Friction chart, Psychrometric chart and Steam table is
permitted.
Q.1 Answer any Four of the following:
20
CB
A3
E2
E
90
83
25
C0
66
14
9E
11
66
E1
1
14
9
B2
B2
ED
5
14
9E
11
B2
ED
5
56
7
3E
2E
A
08
(iii) Sensible Heating
ED
5
E2
EA
CB
A3
3E
2E
A
56
7
ED
5
56
7
90
CB
A
3E
2E
A
90
CB
A
58
3
58
3
90
CB
A
3E
2E
A
56
7
Q.3 a) A Vapour Compression Refrigeration System using R-12 works between -25°C and 40°C
as evaporator & condenser temperature respectively. Using P-h chart, Determine;
1. COP.
2. Mass of Refrigerant per TR.
3. Piston Displacement per TR using Volumetric Efficiency = 83%.
4. Heat Rejected in the Condenser per TR.
5. Ideal COP.
12
11
66
11
66
C0
2
58
39
0
C0
2
14
9E
D5
B2
1
49
E
11
66
49
E
B2
1
D5
15040
58
39
0
58
3
66
C0
2
11
49
E
11
66
C0
2
b) Enlist the types of Air Cooling Systems. Explain Simple Air Cooling System with T-S
diagram, processes involved in the cycle & application.
B2
1
56
7E
25
C0
66
9E
11
14
B2
ED
5
b) Explain following Psychrometric Processes with neat sketch.
(i) Heating & Humidification.
(ii) Cooling & Dehumidification.
(iv) Sensible Cooling
56
7
90
CB
A
66
C0
2
CB
83
25
C0
66
C0
90
25
83
CB
90
Q.2 a) A boot strap cooling system of 10 TR Capacity is used in an aeroplane. The ambient air
temperature and pressure are 20 ºC & 0.85 bar respectively. The pressure of air increases from
0.85 bar to 1 bar due to ramming action of air. The pressure of air discharged from the main
compressor is 3 bar. The discharge pressure of air from the auxiliary compressor is 4 bar. The
isentropic efficiency of each compressor is 80%, while that of turbine is 85%. The heat exchanger
effectiveness for both the heat exchanger is 60%. Assuming ramming action to be isentropic, the
required cabin pressure of 0.9 bar and temperature of air leaving the cabin not more than 20 ºC,
Find: Power required to operate the system, COP of system.
12
9E
11
14
B2
ED
5
56
7
3E
2E
A
BA
58
3
02
11
49
E
D5
67
E
67
A3
E2
E
A5
A3
E2
E
A5
67
ED
5B
a) Explain Standard VCR cycle with schematic, P-h & T-S diagrams.
b) Explain the terms SHF, RSHF, GSHF and ERSHF.
c) Define refrigerant and classify refrigerant giving examples of each.
d) Define By-Pass Factor of a coil. Express it for heating & cooling coil. Also define efficiency
of coil.
e) Write short note on Thermal Comfort
f) Define: Specific Humidity, Relative Humidity, DBT, WBT & DPT
Page 1 of 2
567ED5B2149E1166C0258390CBA3E2EA
08
21
49
83
ED
E1
90
B2
66
CB
C0
5
16
B2
56
CB
A5
C0
14
6C
25
A3
7
1
9
2
6
A3
83
ED
4
02
E
5
E
7
9
8
ED
11
2E
90
E
58
E
3
5
1
2
90
B2
66
CB
A5
39
5
1
E
B
6
CB
A5
C0
14
0C
6
67
2
A3
C
14
9E
25
67
A3
ED
BA
0
E2
9E
25
83
ED
11
E2
5B
EA
3E
8
1
9
6
39
5B
16
EA
0C
6C
21
2E
56
0C
6C
21
BA
49
02
56
A5
7E
B
4
0
E1
58
7E
9
2
3
D5
67
A
E
5
E
39
16
3
D
8
ED
1
2
B2
E
3
5
1
EA
0C
6C
2
9
B
6
5B
14
E
0
6
21
BA
02
56
CB
A5
C0
9E
21
4
5
7
9E
25
3E
67
A3
83
ED
11
49
83
ED
11
2E
90
66
E1
E
5
2E
90
B2
66
CB
A5
C0
5
16
B2
CB
A5
C0
14
6C
25
67
A3
1
9
2
6
A3
83
ED
4
E
5
E
7
9
8
E
11
2E
90
E1
E2
39
5B
D5
66
CB
A5
16
E
0
2
B
C
A5
C0
14
6C
67
2
A3
B
1
9E
25
67
A3
ED
4
02
E2
9E
83
ED
11
58
E2
5B
EA
1
9
6
5B
16
EA
0C
6C
21
56
6C
21
BA
49
02
56
7E
4
02
E1
58
7
9
3
D5
ED
E
58
E
3
1
1
2
90
B2
66
39
5
1
E
B
6
CB
A5
C0
14
0C
6
2
C
14
9E
25
67
A3
0
9E
25
83
ED
11
E2
83
11
90
66
5
E
90
B2
66
CB
A5
C0
CB
C0
14
25
67
A3
9E
25
A3
83
ED
E
83
11
2E
90
5
90
B2
66
CB
A5
CB
C0
14
67
A3
9
2
A3
E
E1
58
E2
D5
E2
3
1
EA
90
B2
66
EA
56
C
C
1
BA
49
02
7E
E1
58
3E
D5
39
1
2E
B2
66
0
Paper / Subject Code: 89423 / Heating, Ventilation, Air Conditioning and Refrigeration
QP CODE: 10015040
Q.4 a) The readings from the Sling Psychrometer are as follows;
Dry Bulb Temperature = 30°C; Wet Bulb Temperature = 20°C; Barometric Reading = 740 mm of
Hg;
Using Steam Table, Determine;
1. Dew Point Temperature.
2. Relative Humidity.
3. Specific Humidity.
4. Enthalpy of the mixture per kg of dry air.
10
ED
5B
b) Derive an expression for an equivalent diameter of a circular duct for rectangular duct for same
frictional loss per unit length when quantity of air flowing through both ducts is same.
06
A5
67
c) Write short note on Applications of Refrigeration & AC.
A3
E2
E
25
C0
66
14
9E
11
14
9E
11
B2
ED
5
B2
E2
EA
____________________
11
66
11
66
C0
2
58
39
0
C0
2
58
39
0
CB
A3
3E
2E
A
56
7
ED
5
56
7
49
E
B2
1
D5
14
9E
49
E
15040
11
66
11
66
C0
2
58
3
90
CB
A
3E
2E
A
90
CB
A
58
3
66
C0
2
B2
1
ED
5
56
7
3E
2E
A
90
CB
A
58
3
11
D5
90
83
25
C0
66
E1
1
14
9
B2
ED
5
56
7
3E
2E
A
Q.6) Write short note on any Four of the following:
a) Classification of Heat Pumps.
b) ICE plant.
c) Thermostatic Expansion Valve.
d) ASHRAE Numbering system for Refrigerants.
e) Effective Temperature.
f) Duct design methods.
49
E
56
7E
67
83
25
C0
66
9E
11
14
B2
ED
5
b) Classify cooling towers. Explain any one type in details. Define Tower Range, Tower
Approach & Tower Efficiency.
06
56
7
90
CB
A
66
C0
2
B2
1
CB
90
25
83
CB
90
CB
A3
E2
E
A5
A3
E2
E
Q.5 a) The following data is given for Summer air conditioning of a building:
Outside design conditions = 43°C DBT, 27°C WBT
Inside design conditions = 25°C DBT, 50 %RH
Room Sensible Heat Gain = 84,000 kJ/hr
Room Latent Heat Gain = 21,000 kJ/hr
By-Pass Factor of cooling coil = 0.2
The return air from the room is mixed with the outside air before entering the cooling coil in the
ratio
of 4:1 by mass. Determine;
1. Apparatus Dew Point of the cooling coil.
2. Inlet & Outlet conditions of air for cooling coil.
3. Fresh air mass flow rate.
4. Capacity of cooling coil in TR.
14
C0
66
9E
11
14
B2
ED
5
56
7
3E
2E
A
BA
58
3
02
11
49
E
D5
67
E
04
Page 2 of 2
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