A new, easy way to desalinate water using solar energy

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Alharbawi Naseer Tawfiq Alwan assembled a prototype of the still in the UrFU workshop. Credit: UrFU / Ilya Safarov

The desalter uses a cylinder and a solar collector.

Electrical engineers at the Urals Federal University (UrFU) have developed a new desalination technology. It will significantly reduce the cost of desalination and quadruple the production volume. The research results are published in the journal Thermal Engineering Case Studies.

Today, one of the most popular and simple ways of desalination is by distilling water with the help of solar energy. UrFU scientists, together with Iraqi colleagues, have developed hybrid technology to increase the efficiency of evaporation inside a solar still using a rotating hollow cylinder and a sensor solar.

“We created a desalination technology using a rotating hollow cylinder inside the solar still to accelerate the evaporation of water in the container by forming a thin film of water on the outside and inside surfaces of the cylinder,” which is constantly renewed at each turn. To increase the temperature of the water under the cylinder, we use a solar collector, ”said the head of the Nuclear Power Plants and Renewable Energy Sources Department UrFU Sergei Shcheklein.

In the experiment, the rotational speed of the cylinder inside the solar still was 0.5 rpm. This intensity and time are sufficient to evaporate a thin film of water from the surface of the cylinder. Experimental tests took place in Ekaterinburg, Russia for several months (June-October 2019) and showed high efficiency and reliability of the developed device. In addition, the researchers noted that the relatively high intensity of solar radiation and the low temperature of the ambient air also contributed to the performance of water distillation.

“The performance improvement factor of the created solar still, compared to traditional devices, was at least 280% during the relatively hot months (June, July and August) and at least 300% and 400% during the colder months (September and October). ). At the same time, the cumulative water distillation capacity reached 12.5 l / m2 per day in summer and 3.5 l / m2 per day in winter, ”said Alharbawi Naseer Tawfik Alwan, research engineer at the UrFU and employee of the Technical University of the North (Iraq).

The desalination technology developed with its simple design and low cost could be attractive in the Middle East and Africa – in countries with high solar energy potential and scarcity of fresh water, the researchers say.

In the future, scientists plan to improve the technology and increase the performance of the solar still at the lowest possible investment and operating costs for different climatic conditions.

To note

According to the UN, more than 40% of the world population suffers from water shortages: more than 700 million people on the planet do not have access to drinking water and more than 1.7 billion people living in river basins need additional sources of fresh water.

Reference: “Assessment of Distilled Water Quality and Production Costs of Modified Solar Still Integrated with Outdoor Solar Water Heater” by Naseer T. Alwan, SE Shcheklein and Obed M. Ali, July 3, 2021, Thermal Engineering Case Studies.
DOI: 10.1016 / j.csite.2021.101216

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