Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seawater turns into freshwater through solar energy: A new low-cost technology

08.01.2019

A study conducted at Politecnico di Torino and published by the journal Nature Sustainability promotes an innovative and low-cost technology to turn seawater into drinking water, thanks to the use of solar energy alone

According to FAO estimates, by 2025 nearly 2 billion people may not have enough drinking water to satisfy their daily needs. One of the possible solutions to this problem is desalination, namely treating seawater to make it drinkable.


Solar distiller during the tests carried out in the Ligurian Sea (Varazze, Italy).

Credit: © Politecnico di Torino

However, removing salt from seawater requires 10 to 1000 times more energy than traditional methods of freshwater supply, namely pumping water from rivers or wells.

Motivated by this problem, a team of engineers from the Department of Energy of Politecnico di Torino has devised a new prototype to desalinate seawater in a sustainable and low-cost way, using solar energy more efficiently.

Compared to previous solutions, the developed technology is in fact able to double the amount of water produced at given solar energy, and it may be subject to further efficiency improvement in the near future.

The group of young researchers who recently published these results in the prestigious journal Nature Sustainability is composed of Eliodoro Chiavazzo, Matteo Morciano, Francesca Viglino, Matteo Fasano and Pietro Asinari (Multi-Scale Modeling Lab).

The working principle of the proposed technology is very simple: "Inspired by plants, which transport water from roots to leaves by capillarity and transpiration, our floating device is able to collect seawater using a low-cost porous material, thus avoiding the use of expensive and cumbersome pumps.

The collected seawater is then heated up by solar energy, which sustains the separation of salt from the evaporating water. This process can be facilitated by membranes inserted between contaminated and drinking water to avoid their mixing, similarly to some plants able to survive in marine environments (for example the mangroves)", explain Matteo Fasano and Matteo Morciano.

While conventional 'active' desalination technologies need costly mechanical or electrical components (such as pumps and/or control systems) and require specialized technicians for installation and maintenance, the desalination approach proposed by the team at Politecnico di Torino is based on spontaneous processes occurring without the aid of ancillary machinery and can, therefore, be referred to as 'passive' technology.

All this makes the device inherently inexpensive and simple to install and repair.

The latter features are particularly attractive in coastal regions that are suffering from a chronic shortage of drinking water and are not yet reached by centralized infrastructures and investments.

Up to now, a well-known disadvantage of 'passive' technologies for desalination has been the low energy efficiency as compared to 'active' ones. Researchers at Politecnico di Torino have faced this obstacle with creativity: "While previous studies focused on how to maximize the solar energy absorption, we have shifted the attention to a more efficient management of the absorbed solar thermal energy.

In this way, we have been able to reach record values of productivity up to 20 litres per day of drinking water per square meter exposed to the Sun. The reason behind the performance increase is the 'recycling' of solar heat in several cascade evaporation processes, in line with the philosophy of 'doing more, with less'.

Technologies based on this process are typically called 'multi-effect', and here we provide the first evidence that this strategy can be very effective for 'passive' desalination technologies as well".

After developing the prototype for more than two years and testing it directly in the Ligurian sea (Varazze, Italy), the Politecnico's engineers claim that this technology could have an impact in isolated coastal locations with little drinking water but abundant solar energy, especially in developing countries.

Furthermore, the technology is particularly suitable for providing safe and low-cost drinking water in emergency conditions, for example in areas hit by floods or tsunamis and left isolated for days or weeks from electricity grid and aqueduct. A further application envisioned for this technology are floating gardens for food production, an interesting option especially in overpopulated areas.

The researchers, who continue to work on this issue within the Clean Water Center at Politecnico di Torino, are now looking for possible industrial partners to make the prototype more durable, scalable and versatile. For example, engineered versions of the device could be employed in coastal areas where over-exploitation of groundwater causes the intrusion of saline water into freshwater aquifers (a particularly serious problem in some areas of Southern Italy), or could treat waters polluted by industrial or mining plants.

Media Contact

Pietro Asinari
pietro.asinari@polito.it
39-011-090-4434

http://www.polito.it 

Pietro Asinari | EurekAlert!
Further information:
https://www.nature.com/articles/s41893-018-0186-x
http://dx.doi.org/10.1038/s41893-018-0186-x

More articles from Process Engineering:

nachricht Copper oxide photocathodes: laser experiment reveals location of efficiency loss
10.05.2019 | Helmholtz-Zentrum Berlin für Materialien und Energie

nachricht NIST research sparks new insights on laser welding
02.05.2019 | National Institute of Standards and Technology (NIST)

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 'Nanochains' could increase battery capacity, cut charging time

How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery's negative electrode material. If the battery runs out of these ions, it can't generate an electrical current to run a device and ultimately fails.

Materials with a higher lithium ion storage capacity are either too heavy or the wrong shape to replace graphite, the electrode material currently used in...

Im Focus: Stevens team closes in on 'holy grail' of room temperature quantum computing chips

Photons interact on chip-based system with unprecedented efficiency

To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the...

Im Focus: Happy hour for time-resolved crystallography

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.

The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.

Im Focus: Modular OLED light strips

At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.

Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...

Im Focus: Tomorrow´s coolants of choice

Scientists assess the potential of magnetic-cooling materials

Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

 
Latest News

Quality control in immune communication: Chaperones detect immature signaling molecules in the immune system

20.09.2019 | Life Sciences

Moderately Common Plants Show Highest Relative Losses

20.09.2019 | Life Sciences

The Fluid Fingerprint of Hurricanes

20.09.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>