Recycling purified water from the cooling tower of a power plant not only purifies the air, but also saves water. The Massachusetts Institute of Technology has proven through large-scale testing that this technology is feasible.

The principle of this technology is very simple, but its large-scale promotion is a complex problem. The company needs to gain practical experience from installing prototype systems, first at the gas thermal power plant at MIT, and then promote it at MIT's nuclear research reactor.

In these rigorous tests, it is not only exposed to the heat and vibration of industrial factories in operation, but also to the harsh winter environment of New England. This system has demonstrated its ability to eliminate steam plumes and recapture water. Moreover, it purifies the water during this process, making it 100 times cleaner than the incoming cooling water. The system is now preparing for comprehensive testing in commercial power plants and chemical processing plants.

This technology was envisioned by mechanical engineering professor Kripa Varanasi, aiming to develop a water recovery system by capturing water droplets from natural mist and power plant cooling tower plumes. This project is funded by the MIT Tata Technology and Design Center and aims to improve the efficiency of fog collection systems, such as those used in some arid coastal areas as a source of fog for drinking water.

These systems are typically composed of plastic or metal nets suspended vertically on the path of fog embankments, with extremely low efficiency, capturing only about 1% to 3% of the water passing through them

By first striking small water droplets with a beam of charged particles or ions, each droplet can be lightly charged, making steam collection more efficient. Then, the droplet flow passes through a metal wire mesh with opposite charges, such as a window screen. This will cause droplets to be strongly attracted to the grid, where they fall due to gravity and can be collected in trays placed below the grid.

Laboratory tests have shown this concept, and researchers, along with Dr. Karim Khalil, won the $100000 MIT Entrepreneurship Competition in 2018 with their basic concepts. This new company is called InfiniteCooling by them, with Damak as the executive officer, Khalil as the technical officer, and Varanasi as the chairman. They immediately began installing testing equipment on a cooling tower at the Massachusetts Institute of Technology's Aerodynamic Central Utility Plant, funded by the Massachusetts Institute of Technology's Sustainable Development Office. After testing various configurations, they were able to demonstrate that the system can indeed eliminate plumes and produce high-purity water.

Professor Jacopo Buongiorno from the Department of Nuclear Science and Engineering immediately discovered a great opportunity for collaboration. With the help of NRL engineer EdBlock, he provided the opportunity to further test the system using the research facilities of the Massachusetts Institute of Technology's Nuclear Reactor Laboratory.

With its 24/7 operation and higher temperature steam emissions, the factory will conduct more rigorous practical testing of the system and demonstrate in actual operating reactors approved by the Nuclear Regulatory Commission that this is an important step in "risk reduction" technology, giving power companies confidence in adopting the system.

After installing the system above one of the four cooling towers in the factory, tests showed that the collected water was more than 100 times cleaner than the feed water entering the cooling system. It also proves that the device is different from earlier versions, with its mesh screen installed vertically and parallel to the steam flow, which has no impact on the operation of the factory. The test video vividly illustrates that once the power to the collection network is connected, the white steam plume immediately disappears completely.

The smoke pollution from power plants is very serious and may lead to local opposition to building new power plants, as it may cause blurred vision and even pose traffic hazards when the blurred smoke blows over the road. The ability to eliminate feathers may be an important benefit, allowing plants to be placed in areas that would otherwise be restricted. At the same time, the system can eliminate a large amount of water used by plants, which can then be lost to the air, potentially reducing the pressure on local water supply systems, which is particularly useful in arid areas.

The system is essentially a distillation process, and the pure water it produces can enter the boilers of power plants that require high-purity water - separate from the cooling system. This may reduce the demand for fresh water and purification systems in boilers.

In many arid coastal areas, power plants are directly cooled by seawater. This system can basically increase the desalination capacity of the factory, and its cost is only a small part of building a new independent desalination plant, and its operating cost is also a small part because heat is basically provided for free.

The pollution of water is usually measured by testing its conductivity, which increases with the amount of salt and other pollutants it contains. The water used in the cooling system of power plants is usually 3000 microseconds per centimeter, while the water supply in Cambridge is usually around 500 or 600 microseconds per centimeter. The water captured by this system is usually less than 50 microseconds per centimeter.

Due to the verification provided by the testing facility at the Massachusetts Institute of Technology factory, the company is now able to ensure the arrangement for the first two installations in the operating commercial factory, which should begin later this year. One is a 900 megawatt power plant, where clean water production will be the main advantage, and the other is a chemical manufacturing plant in the Midwest.

In many places, power plants must pay for the water they use for cooling, and the new system is expected to reduce water demand by 20%. For a typical power plant, this alone can save approximately $1 million in water bills annually.

With climate change affecting every aspect of life, including global water supply, companies throughout the entire supply chain are innovating solutions. The testing of this innovative technology at MIT provides a valuable foundation for its consideration in commercial applications.