This document summarizes an experimental study on the impact of fouling on vapor compression refrigeration systems (VCRS). It describes the test rig setup, which includes thermocouples, a condenser, evaporator, display devices, stirrers, pressure gauges, expansion valve, compressor, and drier. It then provides properties of the refrigerant used, details the actual refrigeration cycle, and discusses various losses in VCRS. Mathematical calculations are shown for system components like the expansion valve, evaporator, compressor, and condenser. Graphs illustrate how COP, refrigeration effect, and compressor work vary with parameters like mass flow rate and heat exchanger U-values. The results are then compared to experimental data

1. Impact of Fouling on VCRS and its
experimental study
Guided By: Submitted by:
Mr. Ankit Kulshreshtha
(Project Guide) Piyush Kumar(1101440033)
Rishabh Pandey(1101440040)
Shantanu Kaushik(1101440051)
Shashank Pandey(1101440052)
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2. CONTENTS
Topics
Test rig
Experimental Setup Description
Properties of Refrigerant
Actual Cycle
Losses in VCRS
Mathematical Calculations
Variation of COP with different
parameters
Comparison of Results
Fouling Mitigation
Conclusion
References
Page No.
3
4-9
10-12
13
14
15-20
21-32
33
34-35
36-37
38
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3. Fig No. 1 Refrigeration Test Rig [6]
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4. Experimental setup description[6]
1-Thermocouples: Six thermocouples are used in our test rig.
The readings of the thermocouples are taken by knob by
rotating it .first thermocouple fit at outlet of the condenser.
Second and third thermocouples are fitted in the condenser
tank and evaporator tank respectively. And remaining
thermocouples are fitted in inlet water tank, inlet to
condenser and outlet to evaporator.
2-Condenser and evaporator: - as shown in the figurethe tub
and tube type condenser and evaporator are used in the kit
and the evaporator having insulator on it. These tanks contain
the two mechanicalagitators as shown in figure, for the
continuous mixture the water,the agitator can be controlled
by switch . These tanks have two valves at the lower side of
tanks for the water outlet. A copper tube is used for the flow
of the refrigerant in spiral form in the tub.
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5. Fig No.2 Condenser[6]
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6. Experimental setup description:-
3-Display devices: our refrigeration test-rig contains LED type
display device. All the readings are shown through these
display devices.
4-Stirer: A stirer is used for the proper mixing of water and to
maintain the temperature uniformity throughout the tank and
it is of 1 to 70 hp and 45 watt, 50 Hz and 230 Volt.
5-Rotameter and water tank: rota meter is fitted in
between water tank and the condenser and evaporator
tank and it contains a motor that is used to raise the
pressure of the water and it contains a switch by which
the flow of water can be controlled.
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7. Fig No.3 Evaporator[6]
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8. Experimental setup description:-
6-Expansion valve,compressor and drier: in our refrigeration
test-rig a reciprocating compressor is used to compress the
refrigerant before condenser and it is placed between the
evaporator and condenser and it is of 230 volt,50 Hz and
single phase. The drier is used to absorb the moisture content
and it is placed between the inlet to evaporator and outlet to
the condenser. A copper capillary tube type expansion device
is being used for the expansion of the refrigerant and it is
placed between drier and evaporator.
4/12/2015 8

9. Experimental setup description:-
7-Pressure gauges: – The two pressure gauges are used , one at
high pressure side and other one is placed at the lower
pressure side to measure the condenser pressure and
evaporator pressure respectively. Means one is suction
pressure gauge and other one is discharge pressure gauge,
suction pressure gauge having pressure range from 0 to 150
psi and discharge pressure gauge having pressure range from
0 to 300 psi.
4/12/2015 9

10. Properties of the refrigerant-
Molecular weight: 102.03 g/mol.
Critical point
• Critical temperature: 100.95 °C
• Critical pressure: 40.6 bar
• Critical density: 512 kg/m3
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11. Properties of the refrigerant-
Liquid phase
• Liquid density (1.013 bar and 25 °C (77 °F)) : 1206
kg/m3
• Boiling point (1.013 bar) : -26.55 °C
• Latent heat of vaporization (1.013 bar at boiling
point) : 215.9 kJ/kg
• Vapor pressure (at 20 °C or 68 °F) : 5.7 bar
• Vapor pressure (at 5 °C or 41 °F) : 3.5 bar
• Vapor pressure (at 15 °C or 59 °F) : 4.9 bar
• Vapor pressure (at 50 °C or 122 °F) : 13.2 bar
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12. Properties of the refrigerant-
Gaseous phase
• Gas density (1.013 bar at boiling point) : 5.28
kg/m3
• Gas density (1.013 bar and 15 °C (59 °F)) : 4.25
kg/m3
• Compressibility Factor (Z) (1.013 bar and 15 °C
(59 °F)) : 1
• Specific gravity : 3.25
• Specific volume (1.013 bar and 15 °C (59 °F)) :
0.235 m3/kg
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13. Fig No.4 ACTUAL VAPOR COMPRESSION CYCLE [5]
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14. Fig No.5 Schematic diagram of a simple refrigeration cycle and various
losses in VCR system. [5]
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15. MATHEMATICAL CALCULATION [6]
1.Expansion valve:
h6 = h7 , at P1 and T1, h1 = 297.1 kJ/kg from table,
at T6 = 40.8 and P6 = 1040 kPa , h6 = 109.7 kJ/kg from
table,
pressure loss in condenser = P1 – P6
= 1385.4 – 1040
= 345.4 kPa.
Ploss
cond = 25% of Pc
h6 =h7 = 109.7 kj/kg
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16. MATHEMATICAL CALCULATION[6]
2.Evaporator :-
T7 = -6.90C, h6 =h7 = 109.7 kj/kg, P7 = 225.6 kPa
h7 = hf + x hfg at 225.6 kPa
109.7 = 42.51 + x(246.32 – 42.51)
x = 0.329
T4 = 10.30C, Pe = P4 = 170 kPa , h4 = 262.0 kJ/kg
Pressure loss in evaporator = P7 – P4 =55.6 kPa
Ploss
evap = 25% of Pevap
(Qevap) R = mR ( h4 – h7) = 0.008 (262 – 109.7) = 1.218 kW
(Qevap) W = mW.CPW . ( Two – Twin) = mw.Cpw (T5 –T3)
= 0.046 Х 4.186 (18.3 – 12.4) = 1.134 kW
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17. Qloss
s= 1.218 – 1.134 = 0.08 approx 5% of Qevap
(Qmax)evap = mW.CPW ( Twine – Trine )
= mW.CPW ( T5 – T7 ) = 0.046 Х 4.186 (18.3 + 6.9) = 4.84
kW
Ɛ = (Qevap)w / Qmax = 1.134 / 4.84 = 0.23 = 23%.
Ɛ = (Qevap)R / Qmax ) = 1.218 / 4.84 = 0.25 = 25%.
Qloss
s = mR ( h4 – h7) - mW.CPW . ( Two – Twin)
Refrigeration effect = mR ( h4 – h7) - 0.05 mR ( h4 – h7) = 1.134 kW
Now, Ɛ = 1 – exp(-NTU)
NTU = UA / Cmin
UAe = Cmin. ln(1/ 1 - Ɛ evap)
U = (mW.CPW /Ae) ln(1/1-0.23)
U = ( 0.046 Х 4.186)/0.6619 ln(1/0.77)
U = 75.69 watt/m2 0C.4/12/2015 17

18. MATHEMATICAL CALCULATION:
3.Compressor:
h4 = 262 kJ/kg and S4 = 1.010 kJ/kgK
at 1385.4 = Pb = Pc , Sg = 0.9108 kJ/kgK
since, Sg< S4 hence point lies in the superheated region.
At1385.4 kPa, Sb = 1.006 kJ/kgK at 800C, hb = 308.4 kJ/kg
Ƞ = 0.72 , ƞisentropic = hb – h4 / ha – h4
ha = 262 + (308.4 – 262) / 0.72
= 326.44 kJ/kg
At 326.44 kJ/kg , P = 1385 kPa and T = 920C
4/12/2015 18

19. MATHEMATICAL CALCULATION:
Heat loss in compressor :
mR( h4 - ha) - mR( h4 – hb) = 0.008 (326.44 – 262) – 0.008(308.4
– 262)
= 0.144 kW
Qloss
discharge + Qloss
comp = mR( h1 - ha) = 0.008(326.44 – 297.1) =
0.234 kW
Qloss
discharge = 0.234 - .144 = 0.09 kW
(Wcomp)actual = mR (ha - h4) = 0.008 (326.44 – 262) = 0.515 kW
(Wcomp)isentropic = mR (hb - h4) = 0.008(308.4 – 262) = 0.371 kW
COP = RE / Wcomp = 1.134 / 0.515 = 2.2
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20. MATHEMATICAL CALCULATION:
4.Condenser:
(Qcond)w =mW.CPW . ( Twoc – Twinc) = 0.046 Х 4.186 (26 – 18.3)
= 1.48 kW
(Qcond)R = mR (h1 – h6) = 0.008(297.4 – 109.7) = 1.49 kW
Qmax = mW.CPW (69.1 – 18.3) = 9.76 kW
Ɛcond = (Qcond)w / Qmax = 1.48 / 9.76 = 0.1516i.e. 15.16%
Now, Ɛ = 1 – exp(-NTU)
NTU = UA / Cmin
UAc = Cmin. ln(1/ 1 - Ɛcond)
U = (0.046 Х 4.186) / 0.3301.ln(1/1-0.15)
U = 94.66 watt/m2 0C
4/12/2015 20

21. VARIATION OF COP, REFRIGERATION EFFECT AND
COMPRESSOR WORK WITH MASS FLOW RATE:-
Input
variables
RE Wcomp COP UCond Uevap
mw1
0.046(kg/s)
1.134 kW 0.515 kW 2.04 94.66
(w/m2 0C)
75.69
(w/m2 0C)
mw2
0.07(kg/s)
1.002 kW 0.552 kW 1.80 144
(w/m2 0C)
115.7
(w/m2 0C)
mw3
0.09(kg/s)
0.990 kW 0.672 kW 1.47 185
(w/m2 0C)
148.7
(w/m2 0C)
4/12/2015 21

22. Fig No.6 Graph (Mass flow rate vs COP)
C
O
P
Mass flow rate of water (kg/s)
0
0.5
1
1.5
2
2.5
0.046 0.07 0.09
COP
COP
4/12/2015 22

23. Fig No.7 Graph (COP vs Ucond)
COP
0
20
40
60
80
100
120
140
160
180
200
2.04 1.8 1.47
Ucond (w/m2 0C)
Ucond (w/m2 0C)
4/12/2015 23

24. Fig No.8 Graph (COP vs Uevap)
COP
0
20
40
60
80
100
120
140
160
2.04 1.8 1.47
Uevap (w/m2 0C)
Uevap (w/m2 0C)
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25. Fig No.9 Graph (Mass flow rate of water vs Refrigeration Effect)
Mass flow rate of water (kg/sec)
0.9
0.95
1
1.05
1.1
1.15
0.046 0.07 0.09
REFRIGERATION EFFECT (kW)
REFRIGERATION EFFECT (kW)
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26. Fig No.10 Graph (Compressor Work vs COP)
Compressor work (kW)
0
0.5
1
1.5
2
2.5
0.515 1.002 0.99
COP
COP
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27. Fig No.11 Graph (COP vs Wcomp)
COP
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
2.04 1.8 1.47
Wcomp (kW)
Wcomp (kW)
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28. Fig No.12 Graph (Mass flow rate of water in condenser(kg/sec)
vs COP)
C
O
P
Mass flow rate of water in condenser(kg/sec)
0
0.5
1
1.5
2
2.5
3
3.5
4
0.028 0.046 0.052 0.066
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29. Fig No.13 Graph (Compressor work(watt) vs COP)
C
O
P
Compressor work(watt)
0
0.5
1
1.5
2
2.5
3
3.5
4
208 245 266 308
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30. Fig No.15 Graph (Condenser pressure(bar) vs COP)
C
O
P
Condenser pressure(bar)
0
0.5
1
1.5
2
2.5
3
9.3 10.3 10.8 11.4
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31. VARIATION OF COP WITH TEMPERATURE:
Input temperature (TWinc) (0C) COP
21.2 2.7
25.2 2.47
28 2.04
28.7 1.88
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32. Fig No.16 Graph (Input Temperature vs COP)
COP
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33. COMPARISON BETWEEN MATHEMATICAL AND EXPERIMENTAL RESULTS:
INPUTS MATHEMATICAL
RESULT
EXPERIMENTAL
RESULT
ERROR
( %age)
T1 (0C) 70 69.1 1
T6 (0C) 41 40.8 0.5
T7 (0C) -7 -6.9 1
T4 (0C) 10 10.3 2
COP 2.2 2.04 7
RE (kW) 1.134 1.134 0
Wcomp (kW) 0.515 0.555 7
Ucond (watt/m2 0C) 94.66 94.66 0
Uevap (watt/m2 0C) 75.69 75.66 0
Twoe (0C) 12 12.4 3
Twoc (0C) 26.14 26 0.5
4/12/2015 33

34. Fouling Mitigation
Offline techniques clean heat exchangers by mechanical and/or chemical
means while the system is down, which results in lost production time.
They are labor-intensive and expensive; as much as 8% of the
maintenance costs in a typical industrial plant are due to fouling mitigation
in heat exchangers. When offline mitigation requires the use of aggressive
chemicals, the company is saddled with additional operating costs, and
new problems relating to the increased safety hazards for company
personnel and disposal of toxic waste. Moreover, the fouling process starts
again immediately after cleaning, and the gradual accumulation of
deposits reduces performance until the next cleaning treatment is
initiated. These drawbacks make heat exchanger operation with regular
offline cleaning expensive, cumbersome and inefficient for the entire
industrial process.
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35. Fouling Mitigation
The online method is an ongoing process which uses mechanical
means to keep the heat exchanger clean while it operates.
Some cleaning systems also use chemicals (which must be
carefully adapted to each process), but online mechanical-
only cleaning is both environmentally responsible and highly
cost-effective.
Online mechanical cleaning boosts performance in two ways: it
does not require system shutdown with temporary loss of
operation; and it keeps performance optimal and energy-
efficient through continuous cleaning, which does not allow
any fouling to occur. In addition, online mechanical cleaning
does not only eliminate staff time for cleaning services, but
also purchase of chemicals and waste disposal.
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36. CONCLUSION:-
We have successfully validated the performance of VCR system with
the help of our mathematical model and we have also studied the
effect of various parameters like mass flow rate of water, condenser
pressure, evaporator pressure, input temperatures in condenser
and evaporator,etc on the COP and vapor compression refrigeration
system.
We have also study the fouling phenomenon in the condenser and
evaporator of VCR system.After drawing the curves among various
parameters we conclude that:
1) As mass flow rate of water increases the COP of VCR system
decreases.
2) As overall heat transfer coefficient of evaporator increases the COP
of the VCR system decreases.
3) As overall heat transfer coefficient of condenser increases the COP
of the VCR system decreases.
4/12/2015 36

37. CONCLUSION:-
4) As mass flow rate of water increases the refrigeration effect
decreases.
5) As compressor work increases the COP of the VCR system
decreases.
6) As the condenser pressure increases the COP of the VCR system
decreases.
7) As the evaporator pressure decreases the COP of the VCR system
decreases.
8) As the input temperature increases the COP of the VCR system
decreases.
4/12/2015 37

38. References
1.Cabello, R., Navarro, J., & Torrella, E. (2005). Simplified steady-state
modelling of a single stage vapour compression plant. Model development
and validation.Applied thermal engineering, 25(11), 1740-1752.
2.Qureshi, B. A., & Zubair, S. M. (2012). The impact of fouling on performance
of a vapor compression refrigeration system with integrated mechanical sub-
cooling system. Applied Energy, 92, 750-762.
3.Qureshi, B. A., & Zubair, S. M. (2014). The impact of fouling on the
condenser of a vapor compression refrigeration system: An experimental
observation.International Journal of Refrigeration, 38, 260-266.
4.Cabello, R., Torrella, E., & Navarro-Esbrı́, J. (2004). Experimental evaluation
of a vapour compression plant performance using R134a, R407C and R22 as
working fluids. Applied thermal engineering, 24(13), 1905-1917.
5.Arora,C.P. (2014) , Actual Vapour Compression Refrigeration Cycle.
Refrigeration and Air Conditioning, 114-115
6. Katiyar,C.,Yadav,A.,Singh,R.P.,Soni,R.K. & Awasthi,Hrydesh.(2014), Impact of
Fouling on VCR System.
4/12/2015 38