Effect of Solar Daylighting on Indoor Visual Environment for an Office Space
Project 2 Report Final
1. Holmes, Opella, Partin, Ly 1
ME 3322: Thermodynamics II
Design Project
Dr. Luciano Castillo
Parabolic Dish Solar-Thermal Powered Multi Stage Flash Desalination Plant
Design Group Members:
Abigail Holmes, Jessie Opella, Kyle Partin, Khoi Ly
2. Holmes, Opella, Partin, Ly 2
Abstract
A combined solution for the lack of clean water around the world and the environmental sustainability
problem due to current use of non-renewable energy leads to severaldesigns of renewable energy powered
desalination plants. Hurghada, Egypt has been chosen in this study due to the advantages in terms of
geographic location (proximity to the seawater and the availability of inexpensive land) and suitable
environmental conditions. In this study, a novel combination of parabolic dish system asa renewable energy
source and multi-stage flash desalination plant have been designed and analyzed to supply sufficient water
for 150,000 people Instead of constructing one single large plant for 150,000 people, this study shows that
five small plants, each producing water for 30,000 people, seems to be more economical and convenient in
several aspects. Several factors including system design concept, thermodynamic performance, water
production, water quality, as well as economic cost analysis are considered in this study. The overall
theoretical construction cost, including labor, of 7,201,597USD indicates a promising project for actual
plant construction.
3. Holmes, Opella, Partin, Ly 3
Table of Content
I. Introduction 4
II. Location Environment and Solar Irradiation 6
III. MSF-PDR Desalination System Design
Assumptions 7
Multi-Stage Flash Design and Analysis 7
Parabolic Dish Reflector Design and Analysis 9
Clean Water Evaporation and Condensation Calculation 10
Efficiency 10
Innovation 11
Scaling and Cost Analysis 11
Water Quality 13
IV. Prototype Design and Analysis 13
V. Discussion and Conclusion 14
VI. Reference 15
4. Holmes, Opella, Partin, Ly 4
I. Introduction
There is an increasing demand for electricity, yet fossil fuel resources are limited and byproducts of
burning fossil fuel for electricity cause greenhouse emissions. Therefore,severalcountries around the world
are looking for clean, affordable, and renewable energy sources. Among different renewable energy
sources, including solar energy, geothermal energy, wind energy, and hydroelectricity, solar energy
gradually receives more attention and interest from research institutes and industries. Solar energy is a
promising, renewable, and potentially unlimited energy supply. Sunlight, the largest available carbon-
neutral energy source, provides the earth with more energy in one hour than is consumed on the planet in
an entire year (Barlev et al., 2011). Despite this, solar electricity currently provides only 0.4% of total U.S.
Central Station Electricity Generation. (EIA, 2015). Figure 1 represents the world map of global horizontal
irradiation in 2013. According to this figure, any region within 45 degree Latitude North and 45 degree
Latitude South received more than 1700 kWh/m2
of sun energy in the entire year 2013 (Solargis, 2013).
Virtually all of these regions are qualified for solar energy plants installation.
Figure 1: Global Horizontal Irradiation 2013 Annual Sum (Solargis, 2013)
There are two mainstream technologies for harvesting the sun energy: photovoltaics (PV) and
concentrated solar power (CSP). The former involves the use of solar cells to generate electricity directly
via the photoelectric effect. The latter employs different methods of capturing solar thermal energy for use
in power-producing heat processes. This paper will mainly focus on the development and research of CSP.
CSP is a technology that uses heat provided by solar irradiation concentrated on a small area. Using mirrors
with specific orientations, sunlight is reflected to a receiver where heat is collected by a thermal energy
carrier, and subsequently used directly (in the case of water/steam) or via a secondary circuit to power a
turbine and generate electricity. The geometry and orientation of mirrors, and the placement of heat
receivers are all categorized into four most common sunlight collecting technologies: Parabolic Trough
Collector (PTC),Linear Fresnel Reflector (LFR), Solar Tower Power (STP), and Parabolic Dish Reflector
(PDR) (Figure 2). PTC system is the most mature and commercially used. However,PDR was used in this
study due to high thermodynamic efficiency and the potential for mass production (table 1).
5. Holmes, Opella, Partin, Ly 5
Figure 2: Currently available CSP Technologies:(a) STP; (b)PTC; (c) LFR; (d) PDR (OECD/IEA, 2010)
Relative
cost
Land
Occupancy
Thermo-
dynamic
efficiency
Operating
T Range
(deg C)
Solar
Concentration
Ratio
Outlook for
improvement
PTC Low Large Low 20-400 15-45 Limited
LFR Very Low Medium Low 50-300 10-40 Significant
SPT High Medium High 300-565 150-1500 Very
Significant
PDC Very High Small High 120-1500 100-1000 High
potential
through mass
production
Table 1: Comparison economics and performance between four CSP technologies (OECD/IEA, 2010; Sargent, 2003; Barlev et
al., 2011)
Similar to the importance of energy of the world in the recent year, clean water plays a fundamental
role in human activities, from usage for daily needs to industrial applications. However, as of 2013, 783
million people do not have access to clean water and almost 2.5 billion do not have access to adequate
sanitation. (UN-Water,2013). The lack of access to clean water sources in remote, dry, and deserted areas
fosters research on removing minerals and salts from saline water (either from sea,river, or soil water), a
process called desalination. The scarcity of water and the availability of solar radiation make solar energy
the most suitable option to mitigate the water deficit (Zaragoza,2014). Some of the most common types of
desalination processes include distillation, reverse osmosis (RO), electrodialysis (ED), and mechanical
vapor compression (MVC). RO, ED, and MVC are well matched with solar PV technology and not fitted
with CSP technology. For this reason, distillation process is utilized in this study analysis. Distillation
process includes four major technologies: Multistage Flash Desalination (MSF), Multi-Effect Desalination
(MED), Adsorption Desalination (AD), and Membrane Distillation (MD). MSF is a process that distills
seawater by flashing a portion of the water into steam in multiple stages of countercurrent heat exchanger.
MED is similar to the MSF Distillation process with the difference that feed water exchanges heat with the
vapor in one effects then becomes the vapor that exchanges heat with the feed water in the next effect. In
6. Holmes, Opella, Partin, Ly 6
AD, an adsorbent is used to suck vapor produced in the evaporator at very low pressure and temperature
and it released the vapor when heated. MD, on the other hand, is a thermally driven process that utilizes a
hydrophobic, microporous membrane as a contactor to achieve separation by liquid-vapor equilibrium.
There are several MSF desalination plants around the world that employ solar thermal system for
desalination process. The first solar MSF desalination plant was designed and tested at the Kuwait Institute
for Scientific Research.The installation consists of a self-regulating MSF system, producing 100 m3/d fresh
water,and of 220 m2 line-concentrating collector arrays (Kriesi, 1983). Jebel Ali Desalination Plant, UAE
was capable to produce 2060 MW of power, and 140 million gallons of water a day. The installation of the
plant cost 2.72USD Million and consisted of 234 Megawatt gas turbines and 8 MSF units (Apropedia,
2013). In La-Paz,Mexico, a 10-stage MSF desalination plant is in operation producing 10 m3/d freshwater.
The collector field consists of two arrays of flat-plate system, 194 m2
and a stand by having 160 m and
parabolic concentrators with 160 m2
collecting area (Scholle and Schubert, 1980). Khoshaim (1985)
introduced 200 m3/day solar seawater desalination prototype with 18 parabolic dish reflectors. Each
reflector has 80.3 m2
of reflective area with 98% reflectivity, 350-500:1 concentration ratio, and 0.6 kW m
-2 collection threshold. However,the study did not clearly mention the efficiency of the system, and how
much feed seawater was input. To the best of our knowledge, there have been no development on using
PDR for MSF seawater desalination.
The performance of a novel desalination system design by combining PDR and MSF concepts is
examined. This study will perform a parallel analysis on two aspects of design. The first analysis will focus
on theoretical performance of the solar thermal desalination system for 150,000 residents in Hurghada,
Egypt. Since there are five identical plants will be built in five different location in Hurghada, the system
performance analysis will focus on one out five plants. The second analysis will be performed on the
economic cost the same design concept. The prototype consisting of two parabolic dishes for sunlight
concentration and two MSF units for the desalination process is included in this study. The examination on
efficiency, water quality and production, installation and maintenance cost of the actual plant, and the
environmental factors will also be considered.
II. Location Environment and Solar Irradiation
Hurghada, Egypt is located 27.2578o
N and 33.8117o
E. Annual average solar radiation horizontal 5.93
kWh/m2
day, average air temperature is 23.1o
C, average relative humidity 31.5%, and an average wind
speed of 3.8 m/s (NASA,2015), these characteristics have small deviation throughout the year. Hurghada
is considered a suitable location for solar powered desalination installation because it has high solar
irradiation with long sunlight hour, a lack of clean water,and proximity to the Red Sea. According to the
National Oceanic and Atmospheric Administration, Hurghada also boasts a yearly average of 12 sunny
hours a day, with only 2% of days being overcast (NOAA, 2013).
NASASurface Meteorology and Solar Energy provides monthly average solarirradiation (kWh/m2
day).
However,in order for the sunlight irradiation to be useful for our solar thermal systemperformance analysis,
the data for daily direct beam solar irradiation is needed. Zhang et al. (2013) summarized a set of equations
that help systematically decompose monthly data retrieved from NASA website to daily horizontal solar
irradiation. This source of solar irradiation then is decomposed into direct normal solar irradiation, which
is what neededfor calculation, and diffuse solar irradiation. Figure 3 shows the graph of daily direct normal
solar irradiation in July, 2015 in Hurghada generated using MATLAB Software.
7. Holmes, Opella, Partin, Ly 7
Figure 3: Daily Direct Normal Solar Irradiation for Hurghada, Egypt
III. MSF-PDR Desalination System Design
Assumptions
Several assumptions have been made in order to simplify calculation on the system performance.
Firstly, daily direct beam solar irradiation data were calculated with an assumption that there was no
sunlight blockage from clouds. Secondly, there is a linear temperature gradient from the first MSF Stage to
the last stage. The mean values of specific heat of the brine water and the latent heat of vaporization of the
entire system, not just any individual stage, were used for the performance analysis.
Multi-Stage Flash Design and Analysis
In designing the MSF system, the choice of number of stagesis optimized betweenthe amount of water
production and the cost to build an additional stage. If the number of stages is small, the system does not
have enough hot brine water surface area and heat exchangers to ensure enough clean water production.
Additionally, the brine waterexiting the last stage remains athigh temperature,leaving a significant amount
of heat wasted. On the other hand, building excessive number of stages adds significant amount of cost for
an additional stages without much improvement in clean water production. For these reasons, the system
design in this study has 20 stages,an adequate number for high water production and low construction cost.
Figure 4 represents the simplified diagram of the MSF plant. Heated seawater returns to MSF stages to
evaporate vapor. The vapor exchanges heat with the cold feed sea water, condenses, and going out of the
system.
8. Holmes, Opella, Partin, Ly 8
Figure 4: Multi-Stage Flash System Stages
Figure 5: Calculation and Design Logic for System Performance and Cost
With the assumptions stated in the above section, a set of simplified equations with high accuracy
introduced by Hamed and Aly (1991) were used to build an MATLAB code to graph the amount of clean
water generated from each MSF stage. Since each plant provide sufficient water for 30,000 (there are five
plants total), the Msea = 26kg/s. Figure 6 shows the temperature and the amount of clean water produced in
each stage. When summing up the amount of clean water produced in all stages, Mclean = 1.363 kg/s, or
equivalently 15561 gallon/day (with 12-hour continuous direct sunlight).
First Stage: V1 = Msea Z
Second Stage: V2 = Msea Z (1-Z)
Third Stage: V3 = Msea Z (1-Z)2
9. Holmes, Opella, Partin, Ly 9
Ith Stage: Vi = Msea Z (1-Z)i-1
With Z = Cp (tb1 – tb20)/ (20 λ)
Where Cp and λ are the mean specific heat and latent heat of vaporization of the whole cascade.
Figure 6: Temperature (o
C) and Water Evaporation Rate (kg/s) at Specific Stage
The total heat required into the system was calculated using the following equation:
Qin= -Msea*h(Tinlet)+ Mbrine*h(Toutlet)+Σ Mclean*h(Tclean) (kW)
Parabolic Dish Reflector Design and Analysis
The total heat necessary to achieve the mass flow rates and temperatures stated above in kWh was
calculated to be approximately 15,000 kWh. The calculation for the number of dishes required for the
system utilizes an average value from the daily direct normal solar irradiation data for Hurghada, Egypt of
5.06 kWh/m^2.
It also utilizes the equation for the reflectance of a metal surface in air, as shown below (Photonics
Media, 2015).
Where n is the index of refraction and k is the extinction coefficient of the metal. Both of these
quantities depend on the material and the wavelength of the light (Palik, 1985). The reflective surface on
the mirrors in this system are aluminum. For the purpose of this analysis only the wavelengths associated
with infrared radiation (1-10 μm) were focused on because infrared is most directly related to heat
10. Holmes, Opella, Partin, Ly 10
production. Values of n range from 1.35-25.3 and values of k from 9.58-89.8. This gives a range of
reflectance from 94.45%-98.84%. A midpoint (96.6%) of this range was used for the purpose of
calculations. The reflectance of the visible spectrum is much lower. This could potentially be increased by
selecting mirrors that have higher reflectance; however, this will likely do little for the efficiency of the
system because the majority of the heat production is due to infrared radiation.
Each dish for this system has a reflective surface area of 108ft2
. This value was selected mainly due to
practicality constraints. The average solar irradiation of 5.06 kWh.m^2 was multiplied by this area and by
the reflectance percentage of .966 to result in the heat input per dish (48.88 kWh). The total heat in was
divided by this value to arrive at the total number of dishes required for the system. 307 dishes each with a
reflective area of 108 ft2
are required for a total reflective area of 33156 ft2
.
Clean Water Evaporation and Condensation Calculation
Afterthe amount of waterevaporatedin eachstage wasdetermined, it wasnecessarytowork backwards
and determine the size of the tanks. The evaporation rate is dependent on the evaporation coefficient (θ),
the surface area of the water exposed to air (A),the humidity ratio of the air on the surface of the water (xs),
and the humidity ratio of the atmospheric air (x) (“Evaporation from Water Surfaces”). Using this formula
and working backwards the horizontal cross area of the tanks (which would be the surface area of water
exposed to area) was determined and summarized in a table.
gs = θA(xs-x)/3600
Stage Area (m2
) Stage Area (m2
)
1 10.595565716 11 50.862816835
2 10.591052255 12 62.284088494
3 10.858528743 13 76.724007833
4 11.511477211 14 89.070341035
5 14.271265528 15 107.785802102
6 18.837582105 16 137.990192807
7 23.183278936 17 169.745633490
8 28.996308034 18 215.066661224
9 34.984641515 19 273.850091751
10 41.946131264 20 355.223418576
Table 2: Surface Area Exposed to Water per MSF Stage
Efficiency
The efficiency of this system was defined as heat input to the system divided by the total mass flow
rate of clean water out given in gallons per day. The units of this efficiency are kWh/kg/day. Using the heat
in of 15000 kWh as calculated above and the total mass flow rate of clean water out converted to kg/day as
determined from the MATLAB code as stated above, an efficiency of .2588 kWh/kg/day was calculated.
Since this efficiency is defined as energy in over mass flow rate out, a low number is considered good.
Copper pipe was chosen in this design due to its low cost and third highest thermal conductivity (k =
385 W/m K) after diamond and silver. However, also due to its ability to transfer heat quickly, heat could
be quickly lost if insulation is not considered. Foam and foil wrap insulation tape was used in all pipes in
11. Holmes, Opella, Partin, Ly 11
order to minimize the heat loss effect,which can significantly affect the ability to produce clean water of
the system.
Innovation
This design boasts two main innovations, the goal of both is to reduce the size of the plant and allow
for systems to be built with more limited space, such as a dense metropolitan or slum area,and reduce the
use of potentially harmful chemicals and waste. The primary innovation is that the design foregoes the use
of a thermal heat transfer fluid. The two main HTFs that are widely used are synthetic oils and molten salts.
There are major disadvantages with each. Molten salts must be kept above 120°-220°C to avoid freezing.
When they freeze and then melt again there is a significant risk of cracking the piping ("Turning up the
heat: Molten salt as a heat transfer fluid"). This would be a major concern at night. Synthetic oils are quite
dangerous and costly. Leaking synthetic oils can cause a serious fire hazard. Synthetic oils cost upwards of
175USD per gallon ("High Temperature Heat Transfer Fluid"). The other large innovation in our plant’s
design is splitting up the system into multiple locations – each one independently capable of producing
clean water. Multiple facilities would each contain all the necessary components,but would be individua lly
operated, with separate pipelines, storage tanks, and all other aspects. Each facility would only produce a
portion of the total water,which could be distributed more locally and significantly cheaper,as there would
be little or no transportation costs. This design also would meet a growing population’s demand for more
water because,once the population exceeds the system’s maximum output another small facility could be
built to increase total output. Larger facilities would need to be completely redesigned, or an additional
source of clean water would have to be found.
Scaling and Cost Analysis
In order to design a plant at full scale, capable for providing enough clean drinking water for 150,000
people, the total amount of water a person needs to drink per day must be determined. According to the
United Nations Department of Economic and Social Affairs (UNDESA),a person needs 50 liters of clean
water per day, divided into agricultural, sanitation, food, and drinking categories (UN, 2005). This design
aims to provide a source of clean drinking water,which would amount to 2 liters per person per day. Based
on the meteorological data in Hurgadha, Egypt, the plant would produce water during an average of 12
hours per day, 358 days per year. Overall this would result in our system producing 76,466.48 gallons of
water per day, and pulling in a total of 300,000 gallons of water per facility per day, for the five optimal
facility locations in Hurgadha. Figure 7 shows a map with the five locations indicated.
Figure 7: Possible Facility Locations in Hurghada, Egypt
12. Holmes, Opella, Partin, Ly 12
These five locations were chosen because they met the qualifications: undeveloped land in an
urban/suburban area that was close enough to water and living areas, did not require construction over
archaeological sites (The majority of undeveloped land in Hurghada is protecteddue to archeological finds),
and was at least 4800m2
in size. The total amount of land used would be about 4800m2
for the facility, plus
3000m2
for the pipelines and pump stations, totaling 7800m2
per facility. According to international
Hurghada real-estate company My RealEstate,the cost of land would be about .24USD per m2
(My, 2015).
The larger scale of each facility would require a total of .354 gallons per second of water. The use of
copper and Polyethylene piping, and building for a Factor of Safety of 3, would result in the pipes being
4.65in. diameter, with a wall thickness of 0.36in., allowing for the water to flow at approximately 3fps. The
total length of the copper pipe would be 1100ft., and 65ft of Polyethylene tubing. With pipes of that size
and watermoving atthat rate,307 reflecting dishes, eachwith an area of108ft2
and independently equipped
with a solar tracking system, would be needed to heat the water to 95°C and continue heating the flowing
water.
The boiling and storage tanks would also need to be larger, and there would be 20 tanks, each with an
internal volume of 2610ft3
and wall thickness of 2in., weighing in at 28512lbm total. The tanks would be
made of Polypropylene, which has a melting point of 171°C, and costs a market average of 0.26USD,
bringing the cost per tank at just over 1000USD. Reflecting mirrors with approximately 97% reflectivity
would cost about 7.5USD per ft2. The Reflecting dishes would also be equipped with solar tracking
technology, industrial versions of which cost around 600USD per unit.
There would also be a piping system using 16in steel pipe (standard water main pipe) for transporting
water from the pump stations to the desalination facilities. Each pipeline would weigh about 85 metric tons
and cost about 1,600USD per ton.
A solar powered pump would be used in a full sized plant, to stay within the specifications of the
projects design. The Dankoff SunCentric Surface Pump, made by Dankoff Solar, can pump up to 50,000
gallons a day, is completely solar powered but includes a backup battery, requires no regular maintenance,
and only has to be replaced every 15-20 years. Thus the SunCentric pump meets our requirements and was
chosen as the pump for our plant. It also comes equipped with solar tracking to ensure optimal performance
throughout the day. The exact model, the Dankoff SunCentric 7212 DC Surface Pump, costs 1,726USD
("Dankoff SunCentric Surface Pump").
Land $ 1,927.46 Solar Tracker $ 12,000.00
Pumps $ 10,355.94 Troughs $ 2,361.08
Poly Tube $ 3,240.00 Construction $ 400,000.00
Pipeline $ 135,680.00 Fabrication $ 21,500.00
Dishes $ 180,600.00 Labor $ 500,000.00
Tanks $ 148,262.40 Facility Cost $ 940,319.48
Copper $ 24,392.60 System Cost $ 4,701,597.38
Total Cost $ 7,201,597.38
Table 3: Cost Analysis Totals and by Category, in USD
After the distillation process is complete there will be a considerable amount of waste as brine water.
Fortunately, brine water has lots of uses in several industries; thus, it would be sold to offset costs of the
13. Holmes, Opella, Partin, Ly 13
plant. The brine water can be used to make plastics, batteries, disinfectants, paper, food products, in place
of road salt, as a dust control agent, and many more other options (“7 Ways to Dispose of Brine Waste”,
“Manufacture and Use of Chemicals”). Because there are severalinstitutions that need the waste produced
by our plant, we will be able to sell it. Brine water has a worth of approximately 0.21USD a gallon (Keeps).
At that rate and with a production of approximately 1.06 million gallons of brine a day, the plant would
make 223,500USD a day or 81.6USD million a year just on the selling of brine. This would allow the plant
to pay for itself in just over one month, not including any profit from selling the purified water. According
to the UNDESA,water prices should not exceed 3% of the average local daily income, which translates to
about 0.05USD per gallon (UN, 2005).
Water Quality
Distillation has been used in some form or another for thousands of years by chemists to isolate and
purify certain desired chemicals and as a method for purifying water. The system being analyzed utilizes
distillation as the desalination process. Reverse osmosis is the main alternate method that is used for
desalination. Distillation is much more effective at removing dissolved solids from water than reverse
osmosis. A reverse osmosis systemleaves approximately 4 times as many total dissolved solids in the water
versus the multi-stage flash distillation system. For example distillation significantly reduces the
concentration of fluoride in water (Anjaneyulu, 2012). It reduces the fluoride concentration down to less
than 1.5mg/L, which is well below the limit set by the United States Environmental Protection Agency of
4 mg/L. The only major criticism of the quality of distilled water is that the resulting water is so pure that
it does not contain extra minerals. However,according to The American Medical Journal, the body's need
for minerals is largely met through foods, not drinking water, so this issue is not a major problem.
In this design there is some concern about water quality because copper piping is used throughout the
system. The only area where it is a concern is when the clean water condenses on the copper pipe in order
to be collected. Copper piping is frequently used for water in the U.S. and the only time the copper levels
are a problem is when the water is stagnant in the pipe for a long time (WHO, 2004). In this design, this
problem could be fixed by coating the area of copper pipe that the water is condensing on in a material like
epoxy that helps prevent any copper from dissolving into the water. This could further increase the water
quality that the plant produces.
IV. Prototype Design and Analysis
Figure 8 represents the simplified diagram of the solar powered desalination system prototype. In order
to fully understand how the system works, it is worthy to study and understand the purpose of each
components of the prototype design concept. The cold feed seawatergoing through the inlet pipe to the first
tank will receive a large portion amount of heat from the hot brine water going out from the brine pipe. The
seawater then goes through two heat exchanger coils (6 and 7) in order to condense vapor evaporated after
the heating process is done. The condensed vapor will be obtained and stored as clean, desalinated water.
After receiving a significant amount of heat from the two processes mentioned, the seawater is fully heated
at heating elements 10 and 11 using the concentrated solar power generated by parabolic dishes 12 and 13.
The hot water then travels back to two tanks and exchanges heat with the cold feed seawater.
14. Holmes, Opella, Partin, Ly 14
Figure 8: PrototypeDesign 1) Water pump;2) Brine Pipe; 3) Inlet Pipe;4) First Tank; 5) Second Tank; 6) First Heat Exchanger
Coil; 7) Second Heat Exchanger Coil; 8) Plastic Pipe 6-7; 9) Plastic Pipe7-10; 10) First Heating Element Coil; 11) Second
Heating Element Coil; 12) First Parabolic Dish; 13) Second Parabolic Dish; 14) Faucet Pipe; 15) Connecting Brine Pipe; 16)
Heating Element Connecting Pipe.
V. Discussion and Conclusion
This design is an overall success,meeting its goal to supply drinkable water for 150,000 people at a
low cost, 7.2 million USD for the entire system. The innovative Parabolic Dish Reflector system removes
the need for potentially harmful heat transfer fluids, and splitting the system into five separate facilities
allows for more local, cost effective water distribution and flexibility with a growing population. Locating
the facility in Hurgahda, Egypt also improves the plant’s overall performance and meets water needs for
the local population, as well as providing a stable employment option.
There are three main ways that this system could be improved through future research and analysis.
One area that could be improved is the output waterquality of the system.This could be achieved by coating
the outside of the copper coils in the heat exchangers with a material like epoxy to ensure that no copper is
dissolved into the clean water.The cost analysis could also be made more accurate by finding more specific
material costs by company vendor instead of by weight of material. This would lead to a more accurate
calculation of costs. Lastly, the system analysis could be improved by utilizing hourly irradiation data
throughout the calculations instead of daily averages. This would have an impact on the calculated system
performance because,in actuality, the performance of the system would fluctuate throughout the day based
on current irradiation levels. Future research will be focused on these three things.
In conclusion, there is very limited availability of clean water throughout the world and global a push
for finding ways to utilize clean, renewable energy sources. There is a substantial amount of available solar
radiation that often goes unused. The innovative PDR,MSF system discussed in this paper is presented as
a viable, relatively affordable solution that addresses both of these current issues.
15. Holmes, Opella, Partin, Ly 15
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Facts and Figures, UN-Water,2013.
Handbook of Optical Constants of Solids. Edward D. Palik, ed. (1985). Academic Press.
Hamed, O.,& Aly, S. (1991). Simulation and design of MSF desalination processes. Desalination, 80,1-
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H.G. Scholle, K.P. Schubert,Entsalzungsanlage mit 10 m3 Plannung, Bau und Installation einer solaren
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High Temperature Heat Transfer Fluid. (n.d.). Retrieved December 7,2015, from
http://www.dynalene.com/High-Temperature-Heat-Transfer-Fluid-Dynalene-HT-s/1838.htm
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