factory roof
Factory roofs can trap heat. Image: Pixabay.

Cool surface technology is an immediate and inexpensive solution to South Africa’s efforts to create an economy built on green energy, says SANEDI.

The South African National Energy and Development Institute (SANEDI) says a passive energy cooling solution, used on roofs, walls and/or roads, could impact industries and users alike, from the moment of application.

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South Africa’s energy supply is under constant threat, compounded by a fragile grid that is dealing with an ever-increasing demand.

“Untenable rising energy costs are reducing citizens’ monthly cash flow for other essential necessities. In such a scenario, energy efficiency should be at the front and centre of any energy strategy in this era of economic depression,” says Denise Lundall, project officer for energy efficiency cool surfaces at SANEDI.

“At SANEDI, we are encouraging South Africans to manufacture cool coatings for roofs, walls and roads, establishing new industries and job opportunities. A national rollout of cool surfaces will greatly aid government in not only alleviating pressure on the grid – as a passive energy solution – but also create much-needed local economic development manufacturing and employment opportunities,” explained Lundall.

The idea of creating cool surfaces supports the South African government’s drive to achieve multiple mandates. Cooling a road can, for example, assist the Department of Transport to reduce the need for road maintenance and tire damage as it reduces the surface and ambient temperature of roads, extending its lifespan.

“Cool surface technology can assist the Department of Trade and Industry in the revival of the economy, which includes a product lifecycle from manufacturing, testing to distribution and application. The Department of Human Settlements can benefit from a low-cost intervention that increases the standard of low-cost living, reduces energy costs and limits subsequent maintenance,” she furthered.

Global cool roofs challenge

South Africa, through SANEDI, is one of the ten finalists in the Cool Roofs Challenge along with projects from around the world, all deploying various cooling surface technologies.  

Implemented through SANEDI in partnerships with local municipalities the Cool Roofs Challenge is aimed at scaling cool roof solutions in government subsidised housing.

Working through the municipalities, with the help of community leaders, SANEDI has been identifying locals who are trained as painters. “We train and evaluate, they pass an exam and then get supervised experience. Then 15 people paint 25,000 square metres and you cannot tell me they aren’t qualified painters after that,” said Lundall.

While the current pandemic induced lockdown has slowed down the physical work, SANEDI is working behind the scenes with various government departments to roll out the cool roof technology. In the Western Cape they are working with the City of Cape Town to roll out 26,500 square metres of cool roofs and in Limpopo the Department of Defence will be getting 700,000 square metres of newly cool roofs on their buildings.

Lundall points out that some of the buildings still have asbestos composite roofs, but these can be encapsulated within a membrane before the cool roof paint is applied, dealing with the toxic nature of the asbestos roofs which are very expensive to replace.

Cool surface technology to lower the temperature

“The deployment of cool surface technology also greatly improves urban air quality, reducing energy and health costs.  It reduces the urban heat island (UHI) effect as it cools the ambient temperature over cities, providing resilience to heat events and climate change,” commented Lundall.

An UHI is a metropolitan area that is a lot warmer than the immediate areas surrounding it. Heat is created by energy from people, cars, buses and trains in big and densely populated cities. These UHIs usually have worse air and water quality than its immediate neighbours and night-time temperatures remain high.

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On an individual building scale, cool surfaces improve the thermal comfort of occupants in buildings without mechanical air-conditioning, ideal for schools, warehouses, homes and factories.

“The technology improves health and productivity, saving on medical bills and reducing absenteeism from work and schools. Also, it substantially reduces the cost of building maintenance as it is waterproof, fire retardant, inexpensive, low-tech and quick and easy to deploy,” said Lundall.

 “We cannot control greenhouse gases, but we can give ourselves a little more time. South Arica is not going to stop using fossil fuels [in the immediate future] and we aren’t incentivised sufficiently yet to just switch to renewable energy. So, in the meantime, we need to cool down our ambient temperature. It gives us a gap, we can continue to use fossil fuels, but if we cool down our environment sufficiently it gives us time to boost the use of renewables. We can use this to cool down the planet,” explained Lundall.

SANEDI directs, monitors and conducts South Africa’s energy research and development, promotes the country’s energy research and technology innovation and undertakes measures to promote energy efficiency throughout the economy.