Desalination Skyscraper

By:  | July - 10 - 2020

Editors’ Choice
2020 Skyscraper Competition

Yuanxi Zhang, Na Xie, Henan Wang
China, Japan

At present, the scarcity of freshwater resources is becoming increasingly serious, and it has become a global environmental problem. 97.5% of the total water resources in the world are saltwater resources such as seawater. Data show that more than 70% of the world ’s population lives within 70 km from the seaside. Therefore, desalination is considered to be the most practical method to continuously provide a source of fresh water. Compared to the other two commonly used methods of freshwater withdrawal-underground water withdrawal and remote water diversion, the energy consumption for seawater desalination is low, and raw water resources are abundant.

This project is located in the northern part of the East China Sea, next to Shanghai. China is a country with a severe drought and water shortage. China’s total freshwater resources are less than 2.800 billion cubic meters, accounting for 6% of global water resources, second only to Brazil, Russia, and Canada, ranking fourth in the world. However, China’s population accounts for more than 18% of the world’s total, and its per capita water resources are only 2,300 cubic meters, which is only a quarter of the world average. It is one of the countries with the world’s most per capita water resources. Shanghai’s 6340.5 square kilometers carry a population of 24.278 million. According to the standard of extreme water shortage per capita water resources below 500 cubic meters, Shanghai is in the extreme water shortage zone. How to find a more adequate and sustainable source of freshwater is a problem that must be addressed in urban development.

The current desalination technology is becoming increasingly mature. There are more than 100 scientific research institutions in more than ten countries in the world conducting desalination research, and there are hundreds of desalination facilities with different structures and capacities. A modern large-scale desalination plant can produce thousands, tens of thousands or even millions of tons of freshwater every day. The cost of water is constantly falling, and some countries have reduced it to about the same price as tap water. In some areas, the amount of desalinated water has reached the scale of national and urban water supply.

Recently, a research carried out by a team from Rice University shows that merely focusing incident sunlight into small “hot spots” on a photothermally active desalination membrane dramatically increases––by more than 50%––the flux of distilled water. This large boost inefficiency results from the nearly exponential dependence of water vapor saturation pressure on temperature, and therefore on incident light intensity. Exploiting this inherent but previously unrecognized optical nonlinearity should enable the design of substantially higher-throughput solar thermal desalination methods[1].

This project combines seawater desalination technology with skyscrapers. Using a solar distillation plant, seawater is heated by solar energy turning to steam, and freshwater is obtained after condensation. Then it is used by residents in the building. The wastewater can also be partially recycled after treatment. The basic part of the skyscraper uses parallel dodecahedrons as basic units. Each unit can be used for the cultivation of different marine plants and marine animals as a source of food for the residents of the skyscraper. The skyscraper uses solar panels as curtain walls to convert solar energy into electricity maintaining the normal operation of the entire living system and mechanical system.

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