Technical report product Solar Desalination Plant application ofUtilizing Solar Radiation in Water Desalination by Desert Fish
Executive Summary Our product is a power plant that harvests energy from Solar radiation toutilize it in a much needed application: water desalination. It is a large scaled projectthat we designed to provide fresh water for countries that have sea coasts, but lack innatural fresh water resources. Unlike most of the current water desalination methods, our method is eco-friendly and emission free. Except for a slight need of electrical power, the systemfully operates on solar energy. Our Water desalination process is similar to that of the nature, which happensin the water cycle; saline water is heated by sun, water evaporates free of salt, cloudscondense, and finally, fresh water fall as rain. To speed up this process, we mustintensify the amount of sun rays affecting the saline water. To achieve that, we spreada considerable amount of mirrors that focus Solar rays at a set point about 10 metershigh. At that point, a concave mirror is places to reflect and direct all sunraysdownward on a water container. Within the container, a black metal plate withbranches of wire is fixed. The plates role is to transform most sunlight into heat, anddistribute that heat in the container. The minor need of electricity is operational,where the mirrors are placed on electronic directors to keep in alignment with thesuns position in the sky. After the first phase water goes through, its vapor enter the second phase. Thatis when water vapor is naturally directed to a higher chamber. The chamber isthermally insulated. In addition, tubes of cool water in the walls of the chamber coolsit down. Thus, when the water vapor come into contact with the interior of thechamber, it condenses to stream down as liquid water. Free of excessive unwantedminerals, seawater is good for drinking now! This simple process provides numerous natural and financial advantages.Since our product doesnt burn fossil fuel, it is totally emission free. Hence, it isenvironmentally friendly. Furthermore, present-day water desalination plants use hugeamounts of valuable natural gas, requiring a lot of money. With our product, thatmoney will no longer be necessary.
Need Statement People try to prevent a hazardous an expected Mother Nature event that is juststarting, which is known as global warming. Global warming can be prevented inmany ways, and the main key to prevent it is to use clean energy. Nowadays, mostpeople depend on polluting energy sources (which comes from the burning of fossilfuels; emitting carbon dioxide) in operating almost everything ranging from cars,factories, houses, and other buildings. This resulted in the increase of carbon dioxideemissions by 5.9% in 2010. This increase can be effective in many negative ways, andpeople can predict how much will it increase in the coming years. That’s whyplanning the future is a vital factor. The world should decrease the use of pollutingenergy, and increase the use of clean energy in order to put a stop to global warming. Water is the most vital element for life. Without water, it is impossible tosurvive. Saline oceans make up to 71% of the earth’s surface1. People obtain freshwater directly from lakes and rivers. Whereas ocean (saline) water must undergo aprocess called desalination in order to be good for human consumption or cropirrigation. Studies show that 14,451 water desalination plants around the worldproduce 15.8 billion gallons of water every day. These plants require massiveamounts of energy to function, which can contaminate Earth’s atmosphere. But howvaluable would it be if water desalination plants were to function on clean energy?What a great advantage to the environment and atmosphere that would be! Saudi Arabia is the largest producer of desalinated water in the world. Thegovernment pays annual subsidies at a cost of 3.2 million US dollars for waterdesalination. There are 30 governmental desalination plants that are spread around thecountry. These 30 plants produce over 2.98 million m3 of desalinated water per day.About three million barrels of oil are used to power these plants every day; it isexpected that this number is going to triple in the next five years. Another example is the Jebel Ali desalination plant located in the United ArabEmirates, and it’s the world’s largest desalination plant. Jebel Ali plant is capable ofproducing 300 million m3 of water per year. Such enormous amounts of desalinatedwater require tremendous amounts of energy. Using pure, clean energy is just whatcountries like Saudi Arabia, United Arab Emirates and many others need, looking atthe massive quantities of desalinated water they produce per day using energy that cancause great harm to the environment. 25,000 people die from starvation every day. Somalia is a suitable example forthat. Due to poverty and land dryness, Somalia loses a large number of peoplebecause of hunger, thirst, and diseases. Although Somalia is bordered with the IndianOcean from the east, it doesn’t have the financial abilities nor the facilities to exploitthe ocean in the right way. A large number of countries participated in donatinggenerous sums of money and provisions to Somalia. But the question is: why cantSomalia consistently provide its own provisions? Should people keep on donating or
should they put a plan that will satisfy the needs of the people in Somalia? This is oneof the major problems our world faces today, and such misfortunes require immediatesolutions. As you know water is an essential component that can save the lives ofmany in Somalia. Water is not only used as a hydrant for the human body but it is alsoused to grow crops and create a land full of vegetation for people and animals. In suchproblems, easy fresh water sources are the solution. Looking at these problems happening in our world today, desert fish came upwith an innovative idea that can solve these problems with suitable and appropriatesolutions. We developed a water desalination plant that requires almost nothing butsunlight to fully function. This plant is capable of supplying fresh water in aneconomical and ecological friendly method. Our plan may solve present problems thatare happening in the world today but it can also solve problems in the future. Manypeople talk about global warming and how effective and destructive it is, but the onlysolution for that is to use clean energy that doesnt have a negative effect on Earthsatmosphere. Sunlight is a main source of energy that hasnt been utilized completely,but why do people tend to use other sources of energy that can negatively affect theatmosphere for many important applications rather than using sunlight, which isdramatically better source of energy? Clean energy is the right path to take in order to prevent global warming. Ourinnovative product can make the desalination of water a really simple, inexpensiveprocess, and on top of that, it functions on clean energy. Not only the desalination ofwater should undergo a clean energy process but also everything we use in our dailylife.
Background Technology Our product aims to determine how to harness solar rays as a substitute inwater desalination, and the creation of the quantities involved; such as the amount ofwater, the amount of rays necessary to vaporize the water, and the total time for theprocess. The Desert Fish team was unique because they gathered different technologymethods, used the methods of other well-known products, and researched in the lawsof physical science, then came up with a new, special, and innovative product that is asolution for a worldwide problem. First of all, with the rapid spreading of news channels and forecasts onweather changes, it is not obscure to the world anymore that the vicinity of theMiddle-East and North of Africa are areas that receive the highest amount of solarradiation reaching up to 2400 KW/m2(Kilowatts per Meter squared). Having thisamount of solar natural radiation is one advantage that must be exhausted properly. Amethod had been functioned by constructing huge water containers in the vast deserts,which are isolated from their surroundings using glass. This allows the sunrays topenetrate them to heat the salty water in the containers. The water evaporates; butover a long period of time, similar to the natural processes that form clouds. We usedthe same method, but we adjusted and added enormous things on the original methodin order to intensify the sun radiation and thrive the speed of boiling the water andevaporating in a much quicker passage of time. To intensify the solar radiation, we install mirrors in large quantities aroundthe containers. These mirrors are spread along 50 to 100 meters encircling the glasstanks, wed like to name these: primary mirrors. Primary mirrors are set on electronicdirectors that detect Sun’s position and focus its rays to another concaved mirrorplaced on poles exactly above and facing the container. The Concave mirror is tointensify the primary mirrors rays towards the container. Inside the containers, ablack metal plate, which doesn’t reflect light, is placed in order to heat the water to itsboiling point; hence, speeding up its evaporation. The Primary mirrors are set on electronic directors which helps them to shiftangles in order to absorb the most of the sun’s radiation in all times. We haveresearched and came up with results. An example of one of our studies is: Using 150mirrors with the size of 10m2, and the sun radiation is perpendicular on the mirrorsthe estimated time of reaching the boiling point is 14-16 minutes. With our researchwe also found a technological mirror that is qualified for our product and it can beused as the Primary Mirrors, which are called Fresnel Reflectors. Fresnel reflectorsare made of many thin, flat mirror strips to concentrate sunlight onto tubes throughwhich working fluid is pumped. Flat mirrors allow more reflective surface in the sameamount of space as a parabolic reflector, thus capturing more of the available sunlight,and they are much cheaper than parabolic reflectors. Fresnel reflectors can be used invarious sizes.
Why a Concave mirror? This question might wander around your mind. Theanswer is simple; it is well known that concave mirrors have the shape of an umbrella.If the sunlight that is reflected from the primary mirrors hits any spot in the mirror itwill be directly reflected to one median point in order to have extensive sun radiation. Some criticizers may say that our product is too imaginative to be applied inreality in addition to other alternatives which aim to the exact purpose that could bemore efficient. Well, I clearly stress my words on rejecting the criticizers thought andsay that "Our product is the best alternative to solve this endemic problem, for manyreasons: First, our product could be applied in reality because of the existence ofproducts with same core idea of utilizing solar rays naturally which is applied isSpain. Second, other products may have more efficiency than ours, but I assure youthat our product is part of the high level efficiency while using less amount of energyand money, and that what makes our product really beneficial to the environment andalso makes it a part of the clean energy field."
Concept Details The function of our product, Solar Desalination Plant, is to desalinate salinewater in order to produce fresh water. The structure of the plant is simple, flexible,and expandable. That allows the technology that we innovated, Utilizing SolarRadiation in Water Desalination, to efficiently work with ease and with clearmechanics. All these factors benefits the facility by giving it the capability to adjust tovarious water supply needs. The design of the facility is similar to that of an auditorium. A cylinder watercontainer is located at the center, and arc-shaped rows of mirrors surround it. Abovethe water container at the center, a sector of a big concave mirror hangs on a pole,facing downwards at the container. However, the container and the mirrors around itare not on the same altitude. The mirrors are raised above the surface of the containerby several meters. That allows some space to be available for building steamchambers under the mirrors, but still higher than the containers surface. Furthermore,both the steam chamber and the water container must be under the sea-level. The technology by which our product operates emphasizes the efficiency ofsolar radiation in producing thermal energy. It provides an effective way to harnesssolar energy, convert it into thermal energy, and use that heat in an indispensableapplication: water desalination. Solar rays are collected through reflecting mirrors that are widely spread in asunny area. These mirrors are known as "heliostats". Heliostats have the ability tokeep reflecting sunlight toward a predetermined target. They are controlled bycomputers which calculate Suns position. Also given the heliostats position, thecomputer operate motors that rotate the heliostat to keep it in correct alignment withthe sun and the target. The target however, is not the final destination of the collectedlight. Around 15-30 meters high hangs the target of the heliostats: a concave mirrorwhose role is to reflect a concentrated light beam at the water container under it.Concave mirrors focus defused light at a certain focus point due to the shape of itscurve and the angles of incoming light. Our concave mirror must be designed andpositioned so that its focus point is inside the water container. Its placement at thatheight can be achieved by simply attaching it to a pole from its side. Preferably, theheight of the mirror should be adjustable; it should be attached to a slider on the poleso that it can slide up and down. At the focus point in the container, a sufficient amount of energy is available,but it is in the form of light, and we need to convert it into thermal energy. As lighthits any object, part of that light goes through (as in invisible bodies), another part isreflected back (as in visible bodies), and the remaining light transforms into heat (asin black bodies). To transform as much heat from the light as possible, a black metalplate is placed inside the water container. The metal plate serves for another purpose:the distribution of heat in the container. Therefore, it must be a good heat conductor.
Copper or copper alloys (e.g., bronze, brass) are good materials to build the plate.They are highly conductive, affordable, and less corrosive than many other metals. Since our product is a large scaled facility with multiple operations, itsfeatures are better expressed and understood by describing work process phases ratherthan describing its physical parts. After the energy is collected, saline water goesthrough two main phases in order to desalinate completely: vaporization andcondensation. In chemistry, the process of purifying liquids by vaporization andcondensation is known as distillation. The water comes directly from the ocean through pipes. Because the containeris under the sea-level, the water naturally flows to it from the ocean without any needof pumps. 5 tons of water fill the container, and come into contact with the metal plateinside. The metal plate gets heated up pretty fast by the effect of the concentratedsunlight beam on its surface. By the laws of thermodynamics, when two bodies comeinto physical contact, heat transfers from the hotter (higher temperature) body to thecooler (lower temperature) body until they reach thermal equilibrium (equaltemperatures). Therefore, heat will transfer from the hot plate to the water until theyreach thermal equilibrium. As the beam keeps on heating the plate, the waterstemperature will keep on rising. When the water reaches its boiling point (i.e. 100°C),the continuous thermal energy will start to evaporate the saline water. Waterevaporates free of harmful minerals. For this process to work properly, the container must be thermally insulated.In addition, the top cover of the container must have special features to perform its jobcorrectly. It must be transparent (e.g., glass) so that the beam of light coming fromabove goes through to reach the metal plate. It also must have a special shape so thatits center is low to be in the water close to the plate, and its edges on the edges of thecontainer. That prevents water vapor from blocking the light beam as it might getbetween the cover of the container and the metal plate. Note that the waste when evaporating saline water (i.e. salt) remain as residuein the bottom of the container. Therefore, the container must have a door for dailycleaning. Cleaning is necessary to keep the plant functioning properly. After the water becomes mostly vaporized, valves at the top the containerelectronically open. The valves lead to the steam chamber placed under the heliostats.Because it is higher than the container, as soon as the valves open, water vapornaturally flows into the chamber. The chambers walls are made of thin sheets ofcopper or copper alloys because its highly conductive and less corrosive than othermetals. When water vapor comes into contact with the cooler walls, it condenses andtransforms back to liquid water. Water leak on the walls to collect at the bottom of thechamber. The chambers floor incline downwards to its edge, and thats where a set ofvalves takes the fresh water outside. This is the end of the desalination process.
According to the laws of thermodynamics, the steam chamber will eventuallybecome hot. To keep the desalination process working, we have developed a coolingsystem that needs no energy at all. The chamber is in the shade of the heliostats whichhelps keep it cooler. To prevent the chamber from absorbing heat from itssurroundings, we must thermally insulated it. In addition, the insulation materialwould be white so that it reflects as much sunlight of itself as possible. The insulationmaterial must also be a couple millimeters apart from the metal sheets. That allowsthe most important element of the cooling system to exist. In the apace between, weengrave and define boundaries for water paths. These paths incline downwards fromone edge to another. Cool water from the ocean go through these paths to cool downthe chamber. Eventually, this water becomes warmer, hence, easier to heat up.Through a set of valves, this water goes to the water container for its desalination.This is the water source which fills the container. All valves streaming in/out water or steam is operated electronically by a maincomputer. The computer also calculates temperatures and pressures of different areasof the facility from feedback signaled from electronic sensors. According to theseinformation, the computer opens and closes valves to initiate different phases of theprocess. It is obvious that this desalination plant has special location requirements. Itmust be close to a sea or any water source. Furthermore, it must be its altitude must belower than sea-level. That would probably require excavation works. More importantlocation relating issue is the projects latitude. Sunny places closer to the equator aremore convenient for our project. Actually, major parts of the design changes its shapedepending on the area of construction, e.g., the width of the heliostat row arc and,accordingly, that of the concave mirror sector. Further R&D is necessary for this technology to thrive. Many aspects of theproduct need to be developed, especially building materials. Some information andcalculations are hard for high school students to acquire such as opticalmeasurements.
Sources: 1. http://www.universetoday.com/65588/what-percent-of-earth-is-water/ 2. Lisa Henthorne (November 2009). "The Current State of Desalination". International Desalination Association. Retrieved 2011-09-05. 3. http://sourcing.indiamart.com/engineering/articles/sea-water-desalination- giving-new-lease-life-middle-east/ 4. Applause, At Last, For Desalination Plant, The Tampa Tribune, December 22, 2007. 5. a b International Traffic Network, The world trade in sharks: a compendium of Traffics regional studies, (Traffic International: 1996), p.25 6. New York Times: Global Warming & Climate Change (2011 Durban Conference), updated 21 dec, 2011.