Russian Scientists Develop New Desalination Tech Using Solar Energy

Russia’s Ural Federal University (UrFU) power engineers have developed a new desalination technology, which is expected to significantly reduce the cost of desalination and quadruple the volume of production. The results of the research are published in the journal Case Studies in Thermal Engineering. Desalination plants deserve, and have attracted research efforts because of their high demand, especially in the Persian gulf region, as well as the high energy consumption involved, which demands higher application of renewable energy to keep their carbon emission down.

A popular and simple way of desalination is the distillation of water with the help of solar energy. UrFU scientists, together with colleagues from Iraq, have developed a hybrid technology to increase the efficiency of evaporation inside a solar distiller by means of a rotating hollow cylinder and a solar collector.

“We created a desalination technology by using a rotating hollow cylinder inside the solar distiller to accelerate water evaporation in the vessel by forming a thin film of water on the outer and inner surface of the cylinder, which was constantly renewed with each turn. To increase the temperature of water under the cylinder we used a solar collector,” said Sergei Shcheklein, head of Nuclear Power Plants and Renewable Energy Sources Department at UrFU.

As part of the experiment, the rotation speed of the cylinder inside the solar distiller was 0.5 rpm. This intensity and time is enough to evaporate a thin film of water from the surface of the cylinder. Experimental tests were held in Ekaterinburg for several months (June-October, 2019) and showed high efficiency and reliability of the developed device. In addition, the scientists noted that the relatively high intensity of solar radiation and low ambient air temperature also contributed to the performance of water distillation.

“The performance improvement factor of the created solar distiller, compared to traditional devices, was at least 280% in the relatively hot months (June, July and August) and at least 300% and 400% in the cooler 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,” commented Alharbawi Naseer Tawfik Alwan, a research engineer at the Department of Nuclear Power Plants and Renewable Energy (UrFU) and an employee of Northern Technical University (Iraq).

The developed desalination technology with its simple design and low cost could be of interest abroad – especially in the Middle East and Africa — in countries with high solar energy potential and a shortage of fresh water.

According to the UN, more than 40% of the world’s population suffers from water shortages: more than 700 million people on the planet have no access to clean water, and more than 1.7 billion people living in river basins need additional sources of fresh water.

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

India got its first solar-powered desalination plant with a capacity to generate 10,000 liters of fresh water a day, in March 2019. The plant is built on 120sqm near Vivekananda Memorial at Kanyakumari, Tamil Nadu. The ministry of earth sciences funded Rs 1.22 crore for the project developed by IIT-Madras.

Another solar-powered desalination plant in a small east Indian town, backed by beer maker Carlsberg Group, was built by Desolenator in the Sundarbans delta in West Bengal state in November last year. The plant was expected to start operating this year. The Sundarbans plant will produce about 20,000 liters of clean water per day