1. International Review of Mechanical Engineering (I.RE.M.E.), Vol. 7, N. 6
ISSN 1970-8734 September 2013
Manuscript received August 2013, accepted September 2013 Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
CFD and Experimental Analysis of a Condenser for Domestic
Desalination System
Shashikant. S. Patil1
, A. B. Auti2
, Dr. T. P. Singh3
Symbiosis International University, Lavale, Pune 412 115, India
Abstract – In domestic desalination system, salt water is heated and converted to steam
by using conventional system like LPG or using induction cooker. The steam is then
condensed by the condenser without using electricity which is designed on the basis of the
thermal analysis. Condenser consists of a water tank with copper tubes immersed in it.CFD
analysis is done for the different diameter and length of pipes and the more effective pipe is
found out. Similarly, different shapes of the selected pipes in the tank are decided using
CFD analysis. Finally the system is validated using experimental analysis. Copyright©
2009 Praise Worthy PrizeS.r.l. - All rights reserved.
Keywords: condenser,LMTD, nodes, skewness.
Nomenclature
U Overall heat transfer coefficient (W/m2
K)
Qabs Heat absorbed (Watt)
Qp Heat utilized (Watt)
∆Tm Log mean temperature difference (0
C)
A Area (m2
)
m Mass of water(Liter)
dT Temperature difference (0
C)
Cp Specific heat of water (KJ/KgK)
D Diameter of tube (m)
L Length of tube (m)
I. Introduction
Rural coastal areas in India have electricity problems.
63 per cent of all rural households in India do not have
electricity and use kerosene for lighting [1]. Even for
those rural areas, which are electrified, there is a
tremendous shortage of power supply. Commercial
desalination plants uses electricity for seawater
desalination [2]. Domestic desalination system working
without electricity is not yet available. Water can be
heated using conventional system, but condensation of
steam is not possible. Water can also be heated using
non-conventional energy such as solar energy in which
parabolic concentrator is used to heat water which is kept
in an absorber at the focal area[3].Condenser is
manufactured such that it can be operated without
electricity [5]. Condenser is basically a water tank in
which copper pipe is immersed. When steam flows
through the pipe, heat exchange takes place between
steam and tank water which absorbs the heat from the
steam by converting it to distilled water [7].
The designing is made by considering the amount of
heat that is to be removed. Condenser design depends

2. Shashikant. S. Patil, A. B. Auti, Dr. T. P. Singh
Manuscript received August 2013, accepted September 2013 Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
upon, the quantity of water required for complete
condensation, length and diameter of the pipe.
II. Thermal Analysis
To find out the amount of steam which is generated
during the heating process, it is necessary to find out the
amount of heat supplied to the water. An experiment is
conducted on different quantities of water. Cooker is
heated by a small LPG gas cylinder with a fixed supply
of LPG or using 1KW rating induction cooker. Readings
of initial and final temperature of water are taken after an
interval of five minutes and time required for complete
evaporation is measured.
From the result, it is cleared that the average value of
heat utilized by the water is in the range of 785 to
790Watts. Considering temperature rise of water tank by
25o
C mass of the water in the tank is calculated by,
pabsQ m C dT   (1)
Where, Qabs is the heat absorbed in watts, m is mass of
water in kg/sec. dT is temperature difference between
initial and final water tank temperature which is 25o
C.
790 m 4187 25  
m= 0.007547 kg/sec
m= 27.14 kg/hr
System takes almost 6 hours and 30 minutes to
evaporate 8kg of water. Hence 175 liters of water is
required for condensation of 8kg of water. The amount of
heat transferred to through copper tube is calculated as,
p mQ U A T   (2)
Where, U is overall heat transfer coefficient, whose
value ranges from 800W/m2
to 5000W/m2
K,[4,6] ∆Tm is
log mean temperature difference and A is the area of pipe
in m2
.The total area A, required is 0.0455m2
.This area is
the area of pipe with diameter D and Length L. Copper
tube is selected as it is having more thermal conductivity.
Considering standard sizes of pipe diameter, different
lengths of the pipe can be determined as follow.
A D L   (3)
The results are tabulated below in table I.
TABLE I
LEGTH OF THE TUBE FOR VARIOUS DIAMETERS
Sr. no Diameter(mm) Length(mm)
1 15 1000
2 20 674
3 28 530
III. CFD Analysis
CFD analysis for different combinations of diameter
and length is carried out for finding the minimum
temperature of water at the outlet. For CFD analysis a
tank is generated of required size. Meshing of tank and
tube is done as shown in fig.1 and fig.2. The maximum
number of nodes are up to 500000 with skewness is less
than 0.9 [8].
Fig.1. Meshing on the Tube
Fig.2. Meshing on the Tank
Then boundary condition includes the mass flow rate,
steam temperature and cell zone condition. Highest value
of mass flow rate (0.0365 m/sec) is considered for better
result. Inlet Temperature of steam is given as 373K and

3. Shashikant. S. Patil, A. B. Auti, Dr. T. P. Singh
Manuscript received August 2013, accepted September 2013 Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
outlet fluid for tube is water liquid and inside one is
water vapour. For different values of diameter with
minimum thickness of 1mm of copper tube, CFD
analysis is carried out as follows [8].
III.1. Analysis of 15 mm Diameter Tube
CFD analysis of 15mm diameter with 1000mm length
is shown in fig.3. Outlet temperature of the steam for
15mm diameter is 314K.
Fig.3. Contours of 15 mm diameter tube.
III.2. Analysis 20mm diameter Tube.
CFD analysis of 20mm diameter and length 674mm is
shown in fig.4.Outlet temperature of the steam for 15mm
diameter is 328K.
Fig.4. Contours of 20 mm diameter tube
III.3. Analysis of 28 diameters Tube
CFD analysis of 28mm diameter and 530mm length
is shown in fig.5. Outlet temperature of the steam for
15mm diameter is 341K.
Fig.5. Contours of 28 mm diameter tube.
From above analysis it is observed that 15mm
diameter tube has less temperature at the outlet.
IV. CFD Analysis for Twisted Tube
Another important task is to find the position of the
tube in a tank. A tube may be inclined one or twisted.
The CFD analysis is used to find shape of the tube.
IV.1. Analysis of single twisted tube.
CFD analysis of single twisted tube is shown in the
fig.6. Outlet temperature of the steam is found to be
316K.
Fig.6. Contours of single twisted tube
IV.2. Analysis of Double twisted tube.
Similarly CFD analysis of double twisted tube is
carried out in the similar manner as shown in fig 7. The
outlet temperature of the steam is 312K.

4. Shashikant. S. Patil, A. B. Auti, Dr. T. P. Singh
Manuscript received August 2013, accepted September 2013 Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Fig.7. Contours of double tube
IV.3. Analysis of Triple twisted tube
Similarly CFD analysis of double triple tube is carried
out as shown in fig.8. The outlet temperature of the steam
is 311K.
Fig.8. Contours of triple twisted tube
The above analysis shows that tube with three turns
gives the minimum temperatures of the steam at outlet.
From the analysis it is observed that there is very small
temperature difference between double twisted tube and
triple twisted tubes but as the number of twist increases
fouling factor also get increases. Hence from the both
results double twisted tube with 15 mm diameter is used
for the designing.
V. Experimental Set Up
V.1. Experimental Set Up For 8 kg of Water
As shown in fig.9. The set up consist of black
absorber, LPG system, water tank with copper tubes.
Water kept in black absorber gets heated and converted
to steam. The steam is then passed through tank with the
copper tube. Heat exchange takes place between the tube
and water tank. The temperature of water rises slowly
and the outlet temperature of water after every hour is
noted and tabulated below in table II.
Fig.9.Experimental setup for 8 kg of water with 175 liters tank
Fig.10. Double twisted copper Tube with 15 mm O.D.
The result of quantity of water condensed and the
outlet temperature of water for the 8 kg of water is
tabulated below in table II. The temperature at the outlet
at the end is found to be 380
C (311K), where as using
CFD, analysis the temperature is 312K.
TABLE II
CONDENSED WATER TEMPERATURE PER HOUR EXPERIMENTALLY
Sr.
no
Time
(Hrs)
Condensed
Water
(ml)
Outlet
Temperature
(0
c)
1 12.00 840 26
2 1.00 890 27
3 2.00 970 28
4 3.00 1080 30
5 4.00 1210 32
6 5.00 1300 33
7 6.26 1450 34

5. Shashikant. S. Patil, A. B. Auti, Dr. T. P. Singh
Manuscript received August 2013, accepted September 2013 Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
V.2. Experimental set up for 12 kg of Water
The second experimentation is carried out for 12kg of
water to validate CFD analysis. Using equation 1 and 2
the tank size of 265 liters is designed as shown in the
fig.11 and the system runs for 9 hours and 45 minutes to
evaporate 12kg of water. The outlet temperature of water
is measured after each hour and tabulated below in table
III.
Fig.11.Experimental setup for 12 kg of water with 265 liters tank
CFD analysis of for this arrangement with 15mm
diameter and 1m length is carried out as shown in fig.12.
The outlet temperature of the steam is found to be 312K,
where as experimental results shows the outlet
temperature is 400
C (313K)
Fig.12.Contour of 12 Kg of water analysis
TABLE III
WATER CONDENSED PER HOUR EXPERIMENTALLY FOR 12 KG OF
WATER
Sr.
no
Time
(hrs)
Condensed
Water/hr
(Experimentally)
Outlet
Temperature/
hr
1 12 850 26
2 1 890 27
3 2 970 28
4 3 1040 29
5 4 1030 30
6 5 1100 32
7 6 1250 34
8 7 1350 35
9 8 1520 37
10 9.43 1680 38
VI. Result and Discussion
For deciding the condenser it is desirable to use tube
diameter of 5/8 inches to 3/4 inches [3]. It has been
observed that 15mm (5/8 inches) diameter tube with
double twisted pipe provides the optimal solution.
Fig.13.Camparison of CFD and experimental analysis for 8 kg of water
Fig.13 shows that the outlet temperature of water
approaches closer to CFD temperature for 8kg analysis
when tank capacity is 17 liters and also from fig.14 it is
cleared that the outlet temperature of water for 12kg
analysis is closed to the CFD temperature when water
tank is 265 liters. From both the analysis, it is proved
that, CFD analysis predicts the outlet temperature of
water and validation using experimental analysis proves
this right.
Fig.14. Comparison of CFD and experimental analysis for 12 kg of
water

6. Shashikant. S. Patil, A. B. Auti, Dr. T. P. Singh
Manuscript received August 2013, accepted September 2013 Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Conclusion
CFD analysis shows the outlet temperature of 38 0
C
where as experiment shows the 34 0
C .This is because of
the heat losses from the tank if we consider these losses
then it will help to optimization of the tank.
References
[1] Rajanish Anil K, Electricity issue in India, Indian Journals.com,
Vol. 1. No.2, April-June2004
[2] Abhijeet Auti , Dr. T. P. Singh , Dr. Dilip R. Pangavhane,
Thermal analysis of parabolic concentrator for finding optical
efficiency by different methods with varying parameters,
International Journal of Engineering and Technology, Vol 5 No 2
Apr-May 2013
[3] Abhijeet B. Auti, T. P. Singh, Mandar S. Sapre , Theoretical,
Experimental and Finite Element Analysis of Heat Loss for
Designing a Parabolic Concentrator, International Review of
Mechanical Engineering, Vol. 7 N. 5, July 2013
[4] Arthur.P.Fraas, Heat Exchanger Design (Wiley-India, 2012, pp.
300-400).
[5] A.B.Auti,Domestic solar water desalination system, Elsevier
Energy Procedia, Volume 14, 2012, pp[1776-1778]
[6] Mahesh Rathor, Enginnering Heat and Mass Transfer (university
Science Press, 2008).
[7] Department of Atomic Energy, Bhabha Atomic Research Centre
Chemical Engineering Group Desalination Division,.
Desalination & Water Purification Technique.
[8] ANSYS thermal analysis guide, Release 12.0; ANSYS, Inc.
website:
http://www1.ansys.com/customer/content/documentation/120/ans
_the.pdf.
He has completed Bachelor of
Mechanical Engineering from Pune
University with First Class from
Imperial college of Engineering and
currently pursuing M.Tech. in
CAD/CAM from Symbiosis Institute of
Technology.
He has completed Bachelor of
Mechanical Engineering and M.E. in
Heat Power from Pune University. He
has a teaching experience of 13 years.
He is working as Assistant Professor at
Symbiosis Institute of Technology and
pursuing Ph.D at Symbiosis
International University. He is the
Author of 12 Engineering books which
have been published for different
universities of India
Dr. T.P.Singh, Director, Symbiosis Institute
of Technology, Symbiosis International
University; Pune received his B.E. Degree
in Mechanical Engineering, M.E. and Ph.
D in Industrial Engineering from Thapar
University, Patiala. He has more than 24
years of teaching experience. He has
supervised M.E. and Ph.D research and
has worked on many sponsored research
and consultancy projects. His
specialization areas include Waste Minimization, Lean Manufacturing,
Flexibility, Technology Management and Electric Discharge
Machining.