Design of Brackish Water Distillation using Cylindrical and Square
Types of Solar Radiation Absorbers Made of Galvanized Base
for Coastal Communities
Dedy Nataniel Ully, Agus Laka, Bernadus Wuwur and Lukas Lantang
Department of Mechanical Engineering, State Politeknk of Kupang, Adi Sucipto, Kupang, Indonesia
Keywords: Brackish Water, Distillation, Radiation, Absorber, Solar Energy.
Abstract: The availability of clean water for people living on the coast is an unsolved problem for various reasons. To
meet the need for clean water consumption, people on the coast only rely on water from shallow wells that
are contaminated with sea water, where it tastes brackish or salty and the quality is not guaranteed. Thus, it is
necessary to apply appropriate technology in the form of distillation of brackish water into fresh water by
utilizing solar energy. The specific purpose of this research is to apply appropriate technology in the form of
a brackish water distillation device into fresh water in order to overcome the clean water crisis for coastal
communities. This research was conducted using real experimental methods in the field and was carried out
at 08:00 am to 04:00 pm with a volume of water in the distillation basin as much as 120 liters. The results
showed that there was an increase in performance with the use of solar radiation absorbent plates. The square
type solar radiation absorber can produce the highest efficiency of 21.63%, while the cylindrical type solar
radiation absorber only produces an efficiency of 21.13%.
1 INTRODUCTION
The availability of clean water on the coast is an
unsolved problem for various reasons. Residents who
live on the coast are dominated by fishermen, so they
have to choose to dig groundwater wells or buy tank
water. To meet the needs of clean water consumption,
people on the coast only rely on water from shallow
wells that are contaminated with sea water, so that it
tastes brackish or salty and the quality is not
guaranteed. To overcome the problem of clean water,
especially in coastal areas, it is necessary to apply
appropriate technology in the form of brackish water
distillation by utilizing solar energy as an energy
source to assist the condensation process, so that this
process is natural and environmentally friendly.
The purpose of this brackish water distillation is
to separate the excess salt in brackish water with the
help of a simple technology, namely solar powered
brackish water distillation. To speed up the process of
absorbing solar heat, it is equipped with a heat-
absorbing plate made of galvanized material which is
square and cylindrical. This is done to speed up the
heating and condensation process and can test the
performance of the two designs of installed solar
radiation absorber plates.
Research on the development of brackish water
distillation into clean water has been carried out by
many previous researchers. In 2006 a research was
conducted on desalination of brackish water to meet
drinking water needs in coastal areas. This research
was conducted with the aim of obtaining important
technical data for design and for use at a factory scale.
The research was conducted using real experimental
methods in the field. From the research results, the
system performance can work well (Siregar and
Siegar, 2019).
Further research will be conducted on micro-scale
reverse osmosis techno-economy analysis for the
process of brackish water distillation. This research
was conducted to obtain an economical design result
for the distillation scale of 12 to 14%. From the results
of the study showed that the evaluation based on NPV
and IRR stated that it was feasible (Adami and
Pudjiastuti, 2017).
Further research was conducted on modeling,
optimization and simulation of various aspects of
brackish water distillation for clean water needs.
Distillation column modeling can help in predicting
Ully, D., Laka, A., Wuwur, B. and Lantang, L.
Design of Brackish Water Distillation using Cylindrical and Square Types of Solar Radiation Absorbers Made of Galvanized Base for Coastal Communities.
DOI: 10.5220/0010938600003260
In Proceedings of the 4th International Conference on Applied Science and Technology on Engineering Science (iCAST-ES 2021), pages 5-10
ISBN: 978-989-758-615-6; ISSN: 2975-8246
Copyright
c
 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)
5

various parameters for the separation between salt
and water elements. The optimal reflux ratio is highly
dependent on the feed mole fraction, feed quality,
relative volatility, and the separation factor being
carried out (Kurkami,2017).
The next research is about the effect of
temperature and operating time on the distillation
process for aquades processing. This research was
conducted with the aim of knowing the temperature
and operating time of the volume of distilled water
produced and to determine the efficiency of the
performance of the distillation apparatus. This
research was conducted using real experimental
methods in the field. The results showed that the
highest efficiency was 51, 30% and obtained a
temperature of 145
O
C (Sivieri and Teixeira, 2019).
Further research on the identification model of
column distillation. This study aims to determine a
suitable model for brackish water distillation. The
results showed the feasibility of using a linear model
to identify the dynamic equation of the distillation
column (Widiasa and Yoshi, 2016).
The next research conducted is about the use of
modeling technology for the process of distillation of
brackish water to meet the needs of clean water. The
purpose of this study is to identify whether this
technology can be applied and developed for
optimization and design purposes. The results of the
study indicate that the model made is able to
successfully describe the concentration and
distribution during the distillation process (Widiasa
and Kusumayanti, 2009).
Furthermore, research was conducted on
experimental studies of the effect of tilt angle on
seawater distillation equipment utilizing solar energy.
The results showed that the greatest potential for solar
radiation at 12.00 am was 908.712 W/m2. This is
caused by the position of the sun perpendicular to the
distillation apparatus. After doing research, the slope
angle of 30
O
is the most effective angle where the
seawater temperature obtained is 73
O
C at 12.30 am,
the radiation heat transfer rate is 92.86 Watts per day
and the fresh water produced is 650 ml (Honarparvar
and Xhang, 2019).
The new contribution of this research is to
overcome the clean water crisis in coastal areas by
applying a simple technology, namely the distillation
of brackish water into fresh water with the addition of
square and cylindrical solar radiation absorber
designs. This is done to speed up the process of
distillation of brackish water, so that production
capacity has increased.
2 RESEARCH METHODOLOGY
Research on the design of brackish water distillation
using square and cylindrical solar radiation absorbers
made of galvanized for coastal communities was
carried out using real experimental methods, where
observations on research objects were carried out in
coastal areas that were young exposed to direct
sunlight. Research was also carried out with the
application of square and cylindrical solar radiation
absorber designs to determine the highest
performance of the two designs. Data collection was
carried out at the same time for both radiation
absorbent designs this sun. The data collection
process was carried out from 8:00 am to 4:00 pm.
Data collection is done every hour and is done
repeatedly for three days, then look for the average
value as valid data for analysis purposes.
The research instruments or installations
regarding the use of square and cylindrical solar
radiation absorbers to support the process of
distillation of brackish water into clean water can be
seen in Figure 1 and 2 below :
Figure 1: Installation of square type solar radiation absorber.
Figure 2: Cylinder type solar radiation absorber installation.
iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science
6

Caption :
IT = solar intensity (W / m
2
).
qr, 1 = The rate of radiation heat transfer from the
collector to the surface in the glass (Watt).
qc, 1 = Convection heat transfer rate from water vapor
to the surface in the glass (Watt).
qc, w = The rate of convection heat transfer from
water to water vapor (Watt).
Qk = Conduction heat transfer rate from the collector
to the outer wall (Watt).
qr, O = The rate of radiation heat transfer from the
glass to the environment (Watts).
qc, O = Convection heat transfer rate from the glass
surface to the environment (Watt).
Ta = Environmental temperature (
O
C).
Tw = water temperature (
O
C).
Tc = glass surface temperature (
O
C).
Tsv = Water vapor temperature (
O
C).
Tp = Temperature of absorbent plate (
O
C).
2.1 Distillation
Distillation is a method of separating liquids from
their mixtures according to differences in boiling
points or the ability of substances to evaporate.
Distillation has a working principle that is when a
substance in a solution does not evaporate equally, it
means that the vapor of the solution will have
different components from the original solution. If
one of the substances evaporates, it means that the
separation will occur completely. But if the two
substances evaporate, the separation process occurs
only partially but the distillate or product will have a
richer precipitate of components than the original
solution.
2.2 Heat Collector
Heat collector is a device that can accommodate heat
which aims to prevent heat drastically. Various types
of heat collectors have been widely used, including
flat plate collectors, tubular heat collectors, flat plate
collectors arranged with a certain slope, collectors
with glass covers and collectors filled with water
flow.
2.3 Radiation
Radiation can be defined as energy emitted in the
form of particles or waves. Solar radiation can
produce energy. The energy produced is used to boil
the brackish water that flows from the brackish water
tank. The power generated from solar radiation is
calculated based on the equation:
ATeP ...
4
τ =
(Watt) (1)
Where :
P = Radiation power (Watt);
e = Emisivity coefficient;
τ
= Constant Stefan Boltzman;
T = Absolute temperature (
O
K);T
A = Cross-sectional area (m
2
)
2.4 Convection
Convection is the transfer of heat accompanied by the
movement of particles. Convection occurs in
substances in the form of gases and liquids. In the
distillation apparatus, heat transfer by convection
occurs in the air between the glass and the space
around the solar basin and in the evaporation of
brackish water. The equation to calculate the power
from convection is:
P = h . A .
T
Δ (Watt) (2)
Where :
P = Convection power (Watt);
h = Transfer rate;
A = Cross-sectional area (m
2
).
2.5 Conduction
Conduction is the transfer of heat through a substance
without the movement of its particles. In the
distillation apparatus, heat transfer by conduction
occurs in the glass and copper pipes. The equation for
calculating power from conduction is:
P = k . A .
d
TΔ
(3)
Where :
k = Thermal conductivity of heat conductor;
A = Cross-sectional area (m
2
);
T
Δ = Temperature change (
O
K);
d = Material thickness (m)
2.6 Heat Resistance
Heat resistance is the losses in the environment and
panels of the solar vapor evaporation system.
Win resistance :
The equation of the wind resistance coefficient is
shown in the equation:
h
c-0
= 5,7 + 3,8. v (4)
Where :
h
c-0
= Wind resistance coefficient;
v =Local wind speed
External radiation resistance :
Design of Brackish Water Distillation using Cylindrical and Square Types of Solar Radiation Absorbers Made of Galvanized Base for
Coastal Communities
7

External radiation resistance is an obstacle caused by
radiation reflected by the glass to the intensity of
heat received from the sun.
hr
-0
=
(
)
44
.
langitgc
TT − τε
(5)
Where :
=
c
ε
Emisivity glass;
=
τ
Coefficient of Stefan Boltzman;
T
g
= Glass surface temperature;
T
sky
= Sky temperature 0,0552 (Ta
1,5
).
2.7 Efficiency
The efficiency of the distillation apparatus is obtained
from the equation:
%100x
T
T
desain
w
= η
(6)
Where :
Tw = Brackish water temperature (
O
C);
T
desain
= Fresh water temperature (
O
C).
The performance of the brackish water distillation
design can be calculated using the following
equation:
 Useful Energy Collektor
OutInU
QQQ −=
(7)
[
]
(. . .).( . ( . .( )
UcLcLcPA
QITAUAUATT ατ =−
 Useful Energy Distillation
t
hmk
Q
fg
du
.
=
−
(8)
 Efficiency of the Destillation
%100x
txIxA
hxmk
Tc
fg
d
= η
(9)
3 RESULT AND DISCUSSION
3.1 Result
Based on the test data in the field, data processing is
carried out for further analysis based on its tendency,
as shown in tables 1 and 2 below:
Table 1: Test results and data processing (square type).
Time
T
sv
(
O
C)
m
k
( kg )
I
T
(W/m
2
)
Q
U-d
(kW)
d
η
(%)
08:00 am 26.10 0 533.42 0 0
09:00 am 35.43 0.129 688.84 0.086 13.91
10:00 am 38.16 0.175 785.02 0.117 16.61
11:00 am 42.66 0.217 853.32 0.144 18.84
12:00 am 43.10 0.259 887.67 0.172 21.63
01:00 p
m
42.96 0.255 893.46 0.169 21.13
02:00 p
m
39.16 0.209 878.08 0.139 17.69
03:00 p
m
38.76 0.159 783.37 0.106 15.09
04:00 p
m
37.33 0.138 723.46 0.092 14.20
Table 2: Test results and data processing (cylinder type).
Time
T
sv
(
O
C)
m
k
( kg )
I
T
(W/m
2
)
Q
U-d
(kW)
d
η
(%)
08:00 am 25.86 0 533.42 0 0
09:00 am 30.93 0.087 688.84 0.058 9.46
10:00 am 33.75 0.126 785.02 0.084 11.99
11:00 am 35.65 0.166 853.32 0.111 14.51
12:00 am 36.00 0.207 887.67 0.138 17.39
01:00 p
m
35.26 0.209 893.46 0.140 17.45
02:00 p
m
35.53 0.167 878.08 0.112 14.18
03:00 p
m
32.93 0.128 783.37 0.086 12.22
04:00 p
m
31.90 0.108 723.46 0.072 11.17
3.2 Discussion
After doing the calculations as shown in the table of
data processing results above, it is displayed in
graphical form, so that it can be discussed based on
existing trends. The discussion in question can be
seen in Figures 2, 3, 4 and 5 below, namely:
Figure 3: Graph of the correlation between time and
distillation useful energy.
From the graph above, it can be seen that the value
of useful energy has increased with increasing data
collection time. At 9.00 am to 12.00 am there was a
linear increase, this happened because the intensity of
solar radiation also increased from time to time until
the maximum occurred at 12.00 am. Furthermore, at
iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science
8

1.00 pm to 4.00 pm continued to decline. The value
of this useful energy is strongly influenced by the
amount of intensity of solar radiation that reflects its
light onto the glass surface, so that condensation
occurs and produces a certain amount of water vapor
with a certain condensate mass.
From the graph, it can be seen that the square
type solar radiation absorber can produce better
useful energy, when compared to the cylindrical type
solar radiation absorber. This happens because the
area of the square type of solar radiation absorber is
larger than the cylindrical type of solar radiation
absorber. The square-type solar radiation absorber
can produce the maximum useful energy of 0.1728
kW, while the cylinder-type solar radiation absorber
only produces 0.140 kW of useful energy, both of
which occur at 12.00 am.
Figure 4: Graph of the correlation between time and
distillation equipment efficiency.
Based on the graph above, it can be seen that the
efficiency value has increased along with the increase
in data collection time. The increase in efficiency
value linearly occurred at 9.00 am to 12.00 am.
Furthermore, the efficiency value decreased from
1.00 pm to 4.00 pm. The efficiency value is strongly
influenced by the mass value of the condensate, the
water vapor produced from the distillation process,
the size of the distillation surface area, the value of
the intensity of solar radiation and the time it takes.
From the graph, it can be seen that the square
type solar radiation absorber can produce the
maximum efficiency value when compared to the
cylindrical type solar radiation absorber. This
happens because the cross-sectional area of the
absorber, the mass of condensate and the resulting
condensation temperature are larger, when compared
to the results obtained from the cylindrical type of
solar radiation absorber.
The square type solar radiation absorber can
produce a maximum efficiency value of 21.63%,
while the cylindrical type solar radiation absorber
only produces a maximum efficiency of 17.45%.
Both the highest efficiency values occurred at 12.00
am, this happened because the highest intensity of
solar radiation occurred at 12.00 am when data
collection was carried out.
Figure 5: Graph of the correlation between time and
condensate.
Based on the graph above, it can be seen that the mass
of condensate produced from the distillation process
has increased with increasing data collection time.
The increase in condensate mass value linearly
occurred at 9.00 am and then decreased from 2.00 pm
to 4.00 pm. From the graph, it can be seen that the
square type solar radiation absorber can produce a
larger condensate mass when compared to the
cylindrical type solar radiation absorber. The
maximum condensate mass value produced by the
square type solar radiation absorber is 0.259 kg, while
the solar radiation absorber only produces a
condensate mass of 0.209 kg, both of which occurred
at 12.00 am.
4 CONCLUSIONS
Based on the results of the discussion above, several
conclusions can be drawn, including:
The square type solar radiation absorber can
produce useful energy, the efficiency and mass of the
condensate is greater, when compared to the
cylindrical type solar radiation absorber.
Design of Brackish Water Distillation using Cylindrical and Square Types of Solar Radiation Absorbers Made of Galvanized Base for
Coastal Communities
9

ACKNOWLEDGEMENTS
On this occasion the author would like to thank all
those who have helped, so that the writing of this
scientific article can be completed properly, namely:
 Mrs. Nonce F. Tuati, SE., M.Si, as the director of
the Kupang State Polytechnic, who has provided
the opportunity to conduct research in an internal
scope.
 Mr. Ramzy Sayonara, ST., MT, as assistant
director II of the Kupang State Polytechnic, who
has allocated research funds every year.
 Mr. Prof. Dr. Adrianus Amheka, ST., M.Eng, as
the head of the research and community service
unit, who has provided direction in conducting
research every year.
 ICAST 2021 colleagues and committee who have
provided guidance and direction in writing this
scientific article.
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