Page 49 - University of Pretoria RESEARCH REVIEW 2018

international collaboration projects. The need continually to increase the processing speed and durability of modern microprocessors in smart- phones, high-performance computing clusters or advanced electronic equipment leads to increased power dissipation and heating. To sustain high speeds and reliable operation, this heat must be dissipated ideally
at the same rate as it is generated, but the current state-of-the-art conventional air-cooling is ineffective with 40% of air not playing a role in dissipating heat. The ThermaSMART RISE project is a joint research programme between 18 universities and three industry partners and investigates the use of phase-change cooling of high-power electronic devices.
Together with Imperial College London and the universities of Lagos and Mauritius, CERG is also involved in a Royal Society Capacity Building Initiative that investigates unsteady boiling that typically occurs in CSP plants when
the sun is suddenly blocked by clouds. The third project is the International Science and Technology Initiatives, a collaboration between MIT, Imperial College London and the University of Pretoria. The purpose of the project
is to study augmented boiling with
nano-engineered surfaces as this can significantly increase the heat transfer performance of CSP heat exchangers.
In the transitional flow regime, Professor Meyer is working with
Dr Marilize Everts, a postdoctoral research fellow in the Department. Their research focuses on the fundamentals of mixed convection flow which potentially has a wide range of applications, but is specifically applicable to solar energy.
Heat exchangers make it possible
to use solar energy for heating, cooling, lighting, electrical power and transportation. A major environmental benefit is that solar energy has no associated air pollution emissions, and therefore plays a critical role in the reduction of future carbon emissions and thereby ensuring a sustainable energy future. The annual global average solar radiation per square meter can produce the same amount of energy as a barrel of oil, 200 kg of coal, or 140 m3 of natural gas. Solar energy is an inexhaustible source of energy that contributes to healthier people and a cleaner environment. This is especially important for South Africa, as the air in Mpumalanga
and the eastern parts of Gauteng is currently the greatest source of
nitrogen dioxide pollution in the world.
Up to now, design engineers have been advised to avoid designing
heat exchangers that operate in
the transitional flow regime, due
to uncertainty and a lack of design information. However, the correlations that were developed by Meyer and Everts now enable them to design heat exchangers that operate in
the transitional flow regime. By implementing the state-of-the-art correlations and research, CSP systems are optimised and their efficiency improves. This will make CSP plants more competitive, compared to other power plants and contribute to lower and stable electricity prices.
Professor Josua Meyer is Head of the Department of Mechanical and Aeronautical Engineering and Chair of the School of Engineering. He received the 2018 UP Chancellor’s Award for Research, in recognition of outstanding research and international stature over an extended period.
Dr Marilize Everts received the 2018 L’Oréal-UNESCO For Women in Science in Sub-Saharan Africa Postdoctoral Award, in recognition of her talent as a young female scientist in the field of Life and Physical Sciences.
47