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INTRODUCTION
The city of Copiapó in Chile occupies a rare, fertile valley in the Atacama desert which Charles Darwin described as a ‘green ribbon’, an ‘island’ in the world’s driest desert. Today, after decades of growth in mining and agriculture – two crucial industries for the Chilean economy – the city faces a crisis, as fresh water resources have been continuously depleted. In recent years, competition for water rights between the two industries has made it more economical for many farmers to sell their water to the mines than it is to grow crops. As a result, the vines of the valley are withering, and the green ribbon is fading into the dust of the desert that surrounds it. The Copiapó Brine Network imagines how we might replace one vital, natural resource by harnessing the potential of two others that are in abundance in the Atacama region; light from the sun, and water from the vast Pacific Ocean. Not only does the region benefit from the greatest potential for solar power in the world, but the materials needed for the construction of such a network are mined and produced locally, from copper for the pipework, to silver for the heliostats. Within the network, a sequence of sustainable hydrological typologies deliver seawater to the city, where it is distilled to produce freshwater using waste heat from the city’s copper smelter, and energy from concentrated solar power. The resultant brine is firstly utilised as an extension to the existing food production in the valley, and subsequently harvested as sea salt for further use. By creating such a network, we might not only address many of the issues that threaten the region’s identity, but in turn, generate new opportunities for architecture, industry and culture.
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SOLAR POTENTIAL
Solar power is a booming technlogy in Chile, considered to have the potential of producing all of the electricity for the country. Northern Chile, home to the Atacama desert boasts the highest solar incidence in the world. The high electricity prices and demand from Chile’s mining industry have driven the demand for more solar generated projects, particularly for large scale commercial or utility projects. Such is the potential of solar power that it has been etimated that if 0.5% of the world’s deserts were used for this technology, it would be possible to supply all the world’s electricity requirements by 2050 (Tried et al, 2006). The energy provided by olar power now ranks as one of the cheapest sources of electric power in Chile, according to a new report by Deutsche Bank. In a Chilean power auction, the bids from solar project developers, between $65 and $68 MWh were more competitive than bids made by coal plants, which were priced at $85 per MWh (Pentland, 2015). Chile has unique economic potential in solar power, and will most likely become a testing ground for the world market. It is Environmental campaigners are hopeful that non-conventional renewables such as solar power could be used as an alternative to dams, and as a possible source of revenue for the nation and energy for the entire region (Watts, 2015). ==
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PARABOLIC DISH With a parabolic dish collector, one or more parabolic dishes concentrate solar energy at a single focal point, similar to the way a reflecting telescope focuses starlight, or a dish antenna focuses radio waves. This geometry may be used in solar furnaces and solar power plants.
PARABOLIC TROUGH With a parabolic dish collector, one or more parabolic dishes concentrate solar energy at a single focal point, similar to the way a reflecting telescope focuses starlight, or a dish antenna focuses radio waves. This geometry may be used in solar furnaces and solar power plants.
POWER TOWER A power tower is a large tower surrounded by tracking mirrors called heliostats. These mirrors align themselves and focus sunlight on the receiver at the top of tower, collected heat is transferred to a power station below. This design reaches very high temperatures. High temperatures are suitable for electricity generation using conventional methods like steam turbine or a direct high temperature chemical reaction such as liquid salt.
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Global Solar irradiance, darker areas have a higher potential for solar power. Data: SolarGIS
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DESALINATION
The scarcity of freshwater in arid and semi-arid countries is a growing crisis, particularly as population levels continue to grow. The demand for water is also accelerating due to industrial development and the increasing demand for agricultural irrigation. Desalination plants are becoming thus becoming increasingly common, with technologies developing to increase efficiency and energy consumption (Ahmed et al, 2000). The desalination process principally involves the separation of salt from water, generating concentrated by-product of brine. There various methods of desalination, which can be categorized into two types. The first involves plants that employ a phase-change process, and single phase processes. The various processes include multi-stage flash (MSF), multi-effect boiling (MEB), vapor compression (VC), solar distillation, and freezing. The second type of desalination includes reverse osmosis (RO) and electrodialysis (ED). Each of the methods differs brine and freshwater output capabilities (Ahmed et al, 2000).
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DISTILLATION Distillation is the process of boilling a liquid solution to separate its component parts, in this case separating water and salt/minerals. Distillation has been used by humans to produce drinking water for thousands of years however and produces the purest water of any form of desalination. Although the energy cost for distillation is high, it is possible to use waste heat from other energy systems to reduce the energy cost dramatically.
REVERSE OSMOSIS Reverse osmosis is the most common membrane system and produces fresh water by forcing seawater through a semipermeable membrane at an extremely high pressure. Most desalination plants being built today use this method as it is very energy efficient compared to other desalination processes.
DIRECT SOLAR Direct solar desalination is the same process that occurs naturally to produce much of the world’s fresh water. As seawater slowly evaporates, water vapour rises into the atmosphere and condenses as clouds. A solar still device can speed up this process and allow us to collect the fresh water for human consumption. In this device, a transparent film allows sunlight into a container filled with seawater. Heat from the sun is trapped, speeding up evaporation, while the shape of the hood allows the fresh water to condense and be transported for use.
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Energy required by existing plants to produce safe drinking water from various sources (kilo-watt-hours per cubic meter)
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DESALINATION SYSTEM COMPARISON
DESALINATION SYSTEM COMPARISON
ne Network
Ryan Canning + Gabriela Mill
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BRINE OUTPUT + DISPOSAL
The desalination process principally involves the separation of salt from water, generating concentrated by-product of brine. It is the disposal of the remaining brine is considered a major setback progressing with desalination technology. If high salinity water is dumped back into the sea as a single load there can be major disruption to the ocean ecosystem. If ponds are left abandoned inland then there is high risk of the pollution of ground water by salts and harmful chemicals (Qurie et al, 2013). An ancient method of separating salt from seawater is salt evaporation ponds. Traditionally, salt was considered a precious resource, and had the potential to generate an entire community around its harvesting. The result was a unique whole food that reflected the identity of that specific region through taste and texture. However as the industry evolved, salt became industrialized, resulting in the abandonment of traditional communities and a product of a lesser quality. Most table salt today is generally indistinguishable from others of the market, a generic taste without any identifiable flavour (Caskey, 2013).
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Within Chile there still remain some traditional salt harvesting communities, such as the Cรกhuil lagoons, south of the city of Pichilemu. The salt ponds are thought to have existed the Spanish invasion nearly 500 years ago, and possibly thousands of years prior to that. The lagoons consist of an expanse of Salt evaporation ponds, shallow man made basins, where salt is separated from seawater by means of solar evaporation. As the water dries up, the remaining salt crystals are harvested by salt workers through raking and piling (Caskey, 2013). Seawater is channelled into the pools during the warmer months. The waters are circulated to avoid any undesired elements. During January and February the ocean water slowly evaporates leaving behind the grey crystals that are later sorted into piles according to their quality. In the surrounding area there are many workers selling bags of salt to visitors of the region (Takekawa, 2001). Recently, evaporation ponds have been successfully utilised in a number of cases to dispose of brine Evaporation ponds are especially suitable in disposing of reject particularly in semi-arid areas due to the abundance of solar energy. While evaporation ponds have long been used for salt production in many parts of the world, the disposal of concentrate from desalination plants is relatively new and is considered to have great potential both economically and environmentally (Ahmed et al, 2000).
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INFRASTRUCTURAL POTENTIAL
The Los Angeles Aqueduct system is a prime example of a water infrastructure system embedded within the identity of a city. As the Los Angeles expanded it became clear that the natural supply of water was insufficient. In the early 20th century, collosal construction project allowed water to be channelled from Sierra Nevada to the city and the surrounding area, completed in 1913 (Libecap, 2007). The aqueduct not only provided water for domestic uses, but ensured reliable irrigation for farms and ranches and nurtured a galaxy of prosperous Southern California suburbs and industrial centers. The system allowed the city to grow from 61 square miles to 440 square miles in ten years, and is still as important and firmly rooted in the city’s history and culture (Monroy, 1999).
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DEVELOPMENT + SYNTHESIS Through understanding the key technological principles we attempted to synthesis and explore architectural oppertunities within the water framework. Our proposals have sought to celebrate engineered elements that are often hidden, such as pipework and mechanical pumps. The architectural interventions capture opportunities within the network for human interaction and spectacle, allowing the water purification process to be enjoyed by citizens and visitors to Copiapรณ
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In
Distillation units
Brine output into salt evaporation ponds
Investigation of potential integration of distillation units within salt haarvesting facility
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Saltworks
Brineworks
Waterworks
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Sketches for Saltworks
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Sketches for Brineworks
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Sketches for Brineworks
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Sketches for Waterworks
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Sketches for waterworks
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Seawater intake
Seawater piped
Distillery
Freshwater open channel Brine open channel
Seawater intake Distillery Salt evaporation ponds dispose of brine
Freshwater piped
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Water dispersal
POTENTIAL ROUTE CONFIGURATIONS I : DISTILLERY AT PAIPOTE Advantages + Usage of excess heat from ENAMI smelter at Paipote to assist water distillation process + Investment oppertunity for state owned company ENAMI - smelter and mines can use seawater + Visual element of open water channels returning to the coast - river appears restored to orginal state Disadvantages - Less area for brine disposal and salt evaporation ponds - More infrastructure required to channel water back to coast
II : DISTILLERY AT COAST Advantages + Minimal construction of infrastructure required to channel water back to coast + Increased potential for brine disposal and salt evaporation ponds - a new hybrid building typology Disadvantages - Functions independantly from mining - less potential for funding - Visual element of open water channel lost - a less visually apealling recreational route
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PROPOSAL From the outset of human civilisation, people have channeled water to meet their needs; from the aqueducts of the Roman Empire to those of California, and the megastructures of China today. Urban development simply cannot exist without such structures. Indeed, life does not exist without water. If we believe that given the current circumstances, water infrastructure will have a necessary role in future urban development, it is vital that we consider its architectural manifestation, and seek opportunities to create a new hydrological typology. Our proposals demonstrate how we might understand available technologies to createa a integrated approach to architecture and engineering. In combatting the critical issue of fresh water shortages we attempt to replace one vital resource by harnessing the power of two others that are in abundance in this area; water from the vast Pacific Ocean, and light from the Sun. This is implemented as a new hydrological network that connects the city to the sea where seawater can be taken for desalination using solar power. Doing so will not only sustain the traditional agriculture industry, but generate new opportunities for art, architecture and industry.
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Copper Ores found throughout the valley
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The potential for new production generated by the network.
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Tracing Darwin’s route through the valley
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Constructing the network using local materials and technologies
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SALTWORKS The Copiapo Brine Network begins at the coastal territory of Puerto Viejo, an informal settlement with a small permanent fishing residence and an influx of thousands over the summer months. The resort serves for many residents of Copiapรณ as an idyllic resort, a coastal escape from the industrial city. There is little in the way of basic services and water infrastructure, and the residence of many temporary residents throughout the summer poses a threat to the sensitive ecological setting. Water is transported from neighbouring towns by car, energy supplied by oil generators and waste is dumped on the coast. This has caused disputes over the inhabitation of the site between the government, the land owners, and the inhabitants.
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At Saltworks, a combined salt harvesting facility and spa is proposed to fill the rocky basin adjacent to the fishing and residential area, aiming to provide new opportunities for the coastal industry and tourism. The creation of an industrial and recreational hub capitalises on the touristic potential of the resort whilst celebrating the unique character of the informal settlement. The water purification process begins as seawater enters the facility to be processed and pumped upwards along the route. . Through the inclusion of water processing facilities it is intended that the water infrastructure shortage of the neighbouring area would improve.
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After being piped to Copiapรณ for desalination, the water is returned to Saltworks in the form of concentrated brine, to be reduced through evaporation into salt form. The brine is initially channelled into the first of a series of evaporation pools. As the brine moves through a succession of pools it finally enters into a pool where the salt is left to crystallise into flakes, a process which can last for weeks. Salt harvesting workers then sweep salt into drying piles before being packaged. The multi coloured appearance of the evaporation ponds is caused by the various types of algae that thrive in specific salinity levels of the water. The harvesting of artisan salt is a lengthy and skilful process, resulting in a product unique in taste and texture to the region.
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BRINEWORKS
Between Puerto Viejo and Copiapรณ lies a green expanse that stretches outwards from the river to the mountains, with some of the most favorable crop growing conditions in Chile. The rows of vineyards supply fruit and vegetables for both the valley and global consumption. In recent years the dried out crop fields are serve as reminders of the water rights farmers have lost to mining companies. A new agricultural and curing hub, Brineworks, is strategically located at the intersection of key transport routes, between the riverbank and the Panamericana Norte motorway to the nearby shipping port Caldera. The position of the hub allows optimum access to export routes and to feed in to the cities growing fruit and vegetable export industry.
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The tower which marks the Brineworks pushes onto the path of the route, encouraging travellers to stop to enjoy the local produce of the surrounding landscape. A bustling marketplace spreads from edges of the fields into the route, inviting the public into the green of the valley to glimpse the thriving agricultural hub. The tower serves for two functions, as an intermediate pumping station for seawater and an outlet for the incoming byproduct of brine from the Waterworks in Paipote. The brine channel flows through an opening in the tower, where it is utilized to cure native produce of the region such as olives, beetroots, onions, and herring. Throughout the network a new brand and identity could be created in series of locally sourced produce, such as salt, cured products, and water.
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WATERWORKS
Located 8 km southeast of the city of Copiapรณ is the district of Paipote, an area synonymous with mining. The Fundiciรณn Hernรกn Videla Lira smelting plant is the first state owned metal refinery of Chile, processing an average of 300,000 metric tonnes of concentrate per year from the mining companies of the Atacama region. The new Waterworks distillery intends to demonstrate through form, scale and public presence a new partnership between the mining, agricultural, and water management sectors. After passing through Brineworks and travelling through the length of the city the route reaches the final destination at Paipote, marked by a water tower atop the summit of the valley hill, and an elongated water distillery unit which bridges across the basin to connect to the smelting plant.
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Despite heavy state investment in local public facilities in the surrounding residential neighbourhood, there have been a number of disputes regarding the environmental contamination caused by high levels of sulphur dioxide i emitted by the smelter. Reports and investigations have legitimised these environmental concerns and the negative impact on the health of the population, forcing the state to initiate a number of decontamination and environmental safety plans. The smelting activity at Paipote is integrated in a sustainable water network, in a system where water and energy are exchanged. The metal refining process uses a high volume for water for a number of processes, with the Paipote plant requiring 1, 384, 500 m3 per year in total (Enami, 2014). Seawater from Puerto Viejo enters through pipe into the Waterworks facility, where a proportion is pumped to the adjacent Paipote smelter for use in 80% of the plant’s operations. The remaining 20% of processes require freshwater, which is also pumped from the water distillery into the smelting facility. The waste heat from the smelter is recovered and utilised in the water distillation process to desalinate the water.
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In addition to the energy recovered from the smelter, the distillery produces power from a connected concentrated solar power plant, for utilisation in water processing operations. The seawater is desalinated using a process of Membrane Distillation, where salt is separated from seawater to enable the recovery of 80% freshwater and a by-product of 20% concentrated brine, where heated water flows through the membrane formed by a number of porous hollow tubes, where only the passage of water vapour is allowed. The water is carried across the hydrophobic membrane through the variety of vapour pressure induced by the difference in temperature. The resulting concentrated brine is released to travel back through the valley in a covered channel for further processing. The freshwater from the distillery is then stored and distributed through copper tanks and pipes, to improve mineral quality, antibacterial properties, and the taste of the water. The freshwater is pumped up to the water tower to be distributed across the valley, to be used both for drinking and agriculture purposes. At a distance the distilled fresh water can be seen exiting the tower through an opening and cascading down the mound, joining path of the pedestrian route to flow back through the valley in its newly purified form.
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CONCLUSION Since the beginning of human civilisation, people have channeled water to meet their needs; from the aqueducts of the Roman Empire to the megastructures of the United States and China today. Urban development simply doesn’t exist without such structures. Indeed, life does not exist without water. Given the emerging global water crisis, it seems likely that these structures will soon play an even more important role in our cities. As architects we must question how a structure so vital for our continued urban development manifests itself architecturally. Despite the important role these structures play, we are rarely given the chance to see or interact with them. The Copiapó Brine Network imagines how this might be done, in a location where water is something that is rare and should be celebrated. Copiapó is in a unique position to use it’s indigenous resources to produce fresh water in a completely sustainable way. To do this, two communities which have competed to buy water rights, must come together for their mutual benefit. The result of this collaboration is not only a functional structure which satisfies existing demand and generates new productive opportunities, but a recreational route which allows the public to interact with the technology that makes the valley green.
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References Ahmed, M., Shayya, W.H., Hoey, D., Mahendran, A., Morris, R. and Al-Handaly, J., 2000. Use of evaporation ponds for brine disposal in desalination plants. Desalination, 130(2), pp.155-168. Banchik, L. 2012. Chile’s thirst for water, Latin American Science. Available: http:// latinamericanscience.org/2014/05/chiles-thirst-for-water/ [accessed: 07/03/16] Caskey, L., 2013. Artisan Salt in South America. Available at: http://eatwineblog. com/2013/07/12/artisan-salt-in-south-america/ ENAMI, 2014, Memoria 2014: Reporte De Sustentabilidad Y Estados Financieros Consolidados. Available: http://www.enami.cl/memorias-y-reportes-desustentabilidad.html Pentland, W. 2015. Solar Power Thrives In Chile, No Subsidies Needed. Forbes. Available: http://www.forbes.com/sites/williampentland/2015/11/07/solar-powerthrives-in-chile-no-subsidies-needed/#2185f843ea4c [accessed: 07/03/16] Libecap, G.D., 2007. Owens Valley revisited: a reassessment of the West’s first great water transfer. Stanford University Press. Monroy, D., 1999. Rebirth: Mexican Los Angeles from the great migration to the great depression. Univ of California Press.
Qurie, M., Abbadi, J., Scrano, L., Mecca, G., Bufo, S.A., Khamis, M. and Karaman, R., 2013. Inland treatment of the brine generated from reverse osmosis advanced membrane wastewater treatment plant using epuvalisation system. International journal of molecular sciences, 14(7), pp.13808-13825. Takekawa, J.Y., Lu, C.T. and Pratt, R.T., 2001. Avian communities in baylands and
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artificial salt evaporation ponds of the San Francisco Bay estuary. In Saline Lakes (pp. 317-328). Springer Netherlands. Trieb, F., KAbarti, M., Bennouna, A., El Nokraschy, H., Hassan, S., Hasni, T., El Bassam, N. and Satoguina, H., 2006. Trans-Mediterranean Interconnection for Concentrating Solar Power, Report by DLR for Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Germany. Watts, J., 2015. Desert tower raises Chile’s solar power ambition to new heights. Available at: http://www.theguardian.com/environment/2015/dec/22/deserttower-raises-chiles-solar-power-ambition-to-new-heights
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