Reflective cool roof surfaces beat SA’s heat

The South African National Energy Development Institute’s (SANEDI) Cool Surfaces Project has moved from collaboration to implementation with the application of reflective roof coatings. A completed scaled-up project in the Northern Cape, reduces indoor daytime temperatures of more than 34°C to more comfortable 25°C, in the low-cost housing project in Groblershoop.

“Cool Surfaces refers to energy-passive materials and technologies used in the construction of the building envelope that improve thermal comfort,” explains Denise Lundall, project manager of Energy Efficiency Cool Surfaces and Communications at SANEDI.

The project began as a collaboration between the South African and US Departments of Energy, under the Clean Energy Ministerial. The Cool Surfaces Project is the response to South Africa’s building need for a quality energy passive, low cost, low maintenance cooling technology that is fire retardant and waterproof.

“There are many materials available, but our current focus is on the Cool Coatings applied to roofs and walls by painting the prepared surface. Surfaces that reflect much of the solar energy and release much of the stored heat energy can materially improve living conditions. Cool surfaces are measured by how much light they reflect (solar reflectance) and how long they hold heat (thermal emittance).

“The idea is to make buildings as un-polluting and energy-efficient as possible. The thermal comfort has improved the residents’ lifestyles massively.

“A cool roof substantially reduces the cooling load of the building, providing several direct benefits to the building owner and occupants. A building that does not have air conditioning, is kept at a cooler and a more constant temperature. In a building with air conditioning, the equipment does not have to work as hard. A cool roof can significantly reduce cooling energy costs. The average energy savings range from approximately 7%-15% of total cooling costs.

“The ‘cool roof’ concept is no longer restricted to roofs alone. In the US, this technology has been extended to surfaces such as pavements. Increasing the solar reflectance of urban surfaces results in reflecting and dispersing more of the incoming global solar radiation, which aids in countering global warming by disrupting the urban heat island effect over human settlements.

“At SANEDI, we are committed to adaptation and mitigation of a wide mix of renewable energy sources and research using current energy technologies efficiently.

“In the roll out of this project, SANEDI collaborates with other government departments to leverage funding. Two SANEDI programmes (Energy Efficiency Programme and Working for Energy) have collaborated to implement Cool Surfaces in a number of demonstration projects. We plan to roll out a scaled up project in each province.

“Skills development is a key component of the project. Local community members attend a 5-day course on specialised coatings, which give participants a SAQA registered certificate, valid for five years, therefore creating job opportunities,” concludes Lundall.