A team from the University of Johannesburg (UJ) Mechanical Engineering department is showing how solar energy can be mobilised using the most humble of components. This is, without a doubt, a technological breakthrough that can provide power to millions across the continent.
Think solar energy and the mind immediately latches on to photovoltaic cells sprawled across roofs or fields of PV units in their thousands all diligently collecting sunbeams. But what if you can’t afford this technology and you work in a location so remote and distant from the towns and cities that installation and maintenance is a problem, even if you could ‘go PV’? Well, then you would talk to Professor Alan Nurick and his team, the Applied Solar Energy Group, at UJ.
The research group is an offshoot of the Mechanical Engineering Science department in the Faculty of Engineering and the Built Environment (FEBE), and it is here that the professor and a band of doctoral, master’s and diploma students find ingenious ways of collecting heat and energy from the sun, largely without the help of photovoltaics or other modern technology.
“It’s amazing what you can do with sun, air, wood and glass,” says Prof Nurick.
Solutions include the use of desalinisation principles in the development of water stills to produce potable water, home air conditioning for both heating and cooling, solar drying for the manufacture of briquettes and crop and fruit drying and curing, and illuminating interior spaces. Much of the research involves the performance of single-paned and multiple-paned windows with and without solar film under different atmospheric conditions.
“To achieve the objectives research is carried out at a more fundamental level into the optical properties of glass. The use of double-paned windows, combined with solar film to reduce heat loads on air conditioning systems and management of illuminance is now an essential element of designing green windows,” says Nurick.
Switching from grid to solar power
In fact, the aim of Nurick’s energy group is two-fold – to replace lighting powered from the national grid with solar illuminance using technology to optimise potential day lighting and to provide an energy source in the absence of a national grid or other energy sources in electrical energy-deprived regions. Dual-paned windows are a focus. Air is drawn from outside a building into the inside, the small volume of air flowing between the glass panes cooling the interior by removing around 20% of the irradiance. “Ultimately,” says Nurick, “the theoretical knowledge and hardware from the research programme will reduce and augment the energy requirements of buildings leading to their greening. Further research could involve modelling of energy efficient buildings, particularly those using new technological developments.”
Scientists like Professor Nurick find themselves at both ends of the tug-of-war rope when deciding on whether to apply intellect or allow free access to the technology on an open-source basis. “I’m all for open access, but there are sensitive and practical considerations that temper such recourse,” says the mechanical engineering professor, a specialist in solar energy.
”For one thing, the university normally funds our research projects, so the IP belongs there. For another, the university invests large sums of money in research of all kinds and if it scores in innovation commercialisation, there’s more money for more research. It’s a righteous circle from that aspect. Broadly speaking, I’d prefer to see our basic technical advances made available open source, especially in the developing world’s rural areas where they can boost economic development.” Nurick quotes his team’s development of a solar dryer as an example. “It’s simplicity itself to build,” he says.
“All you need are the construction plans, some wood, glass and a strip of metal and you are ready to start making briquettes and drying and preserving foods such as grains, vegetables fruit, meat and fish. We calculated that the dryer could stimulate income of between R8,000 ($800) and R10,000 ($1,000) a month. Imagine if a few dozen of these were in operation in the region and what the income could do for the local economy.”
Read about some of the other projects the Applied Solar Energy Group is working in FEBE.