Landscape and architectural devices for energy-efficient South African suburban residential design

Abstract

The study relates international knowledge of climatically responsive and energy-efficient design to work done in South Africa. It also explores the relevance of design devices from international regions to the climates of this country. The research approach explores existing analyses of the main climate regions and the effects of climate factors on human comfort in each, in order to derive appropriate design solutions for the climate of South Africa. In South Africa obstacles exist in the face of energy efficiency. The cheapness of electricity to the consumer and the virtual non-existence of appropriate legislation appear to be two of the most significant obstacles. Design and subsequent construction of suburban residences is carried out with little regard for climatic context. Water is shown to be a particularly scarce and unevenly distributed commodity, which the affluent have greater access to and consume in greater quantities. However, it is demonstrated that the South African climate is virtually ideal for several climate-responsive energy-efficiency techniques. Especially due to the high solar radiation levels there is potential for various active and passive solar design techniques and technologies. The impact of atmospheric temperature and humidity, wind, radiation and precipitation on human comfort is investigated. Humidity and wind are demonstrated to be very influential on human comfort, whereas radiation and wind are the most easily manipulated through design. Furthermore, the specific topography and location of a site can influence the microclimate and solar access of an area to a significant degree. The South African climate is predominantly either hot semi-arid or temperate. Most of the western interior is hot arid whereas the eastern interior and highveld is predominantly temperate, with temperatures increasing to the north and decreasing to the south. The only cool region of the country is found in the highlands of the Drakensberg, with a significant portion of the eastern coast being hot humid. Methodologies and guidelines for both layout, or macro design, and detailed design of residential suburbs are explored. The manipulation of solar radiation, sunlight and wind, as well as the management of rainwater and used household water is explored. It is shown that designing suburbs to create access to solar radiation forms the basis of solar design, with solar access control, material and surface treatment largely determining the success of individual designs. Wind manipulation is achieved mainly through planting design, influencing mostly heat loss and gain ratios into buildings. Effective household water management can substantially reduce its consumption. Further research is needed in all aspects of climate-responsive design, especially classification of the South African climate and development of design techniques adapted to this context.