Sustainable solutions for cooling systems in residential buildings case study in the Western Cape Province, South Africa

Abstract

The energy demand in building sectors for summer air-conditioning is growing exponentially due to thermal loads, increased living standards and occupant comfort demands throughout the last decades. This increasing consumption of primary energy is contributing significantly to emission of greenhouse gases and therefore to global warming. Moreover, fossil fuels, current main sources of energy used for electricity generation, are being depleted at an alarming rate despite continued warning. In addition, most air-conditioning equipment still utilise CFC’s, promoting further destruction of our planet’s protective ozone layer. Concerns over these environmental changes, have begun shifting the emphasis from current cooling methods, to ‘sustainable strategies’ of achieving equally comfortable conditions in building interiors. Study of ancient strategies applied by vernacular architecture shows how the indigenously clean energies to satisfy the cooling need were used. One of the most important influences on vernacular architecture is the macro-climate of the area in which the building is constructed. Mediterranean vernacular architecture, as well as that of much of the Middle East, often includes a courtyard with a fountain or pond; air cooled by water mist and evaporation is drawn through the building by the natural ventilation set up by the building form, and in many cases also includes wind-catchers to draw air through the internal spaces. Similarly, Northern African vernacular designs often have very high thermal mass and small windows to keep the occupants cool. Not only vernacular structure but also the recent development in solar and geothermal cooling technologies could be used to the needs for environmental control. Intelligent coupling of these methods as alternative design strategies could help developing countries such as South Africa toward sustainable development in air conditioning of building. In this paper, the possible strategies for sustainable cooling in residential buildings of Western Cape, South Africa are discussed.