New standards of thermal design to provide comfort and energy efficiency in South African housing
Harris, Howard Charles
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The fundamental objective of this thesis is to determine whether the requirements for thermal comfort in housing in South Arica will provide for the necessary levels of energy efficiency. The effectiveness of various thermal design measures in achieving improvements in energy efficiency is evaluated. These measures are developed into a proposed energy efficiency standard. An estimate is made of the reduction in greenhouse gases which might result from the implementation of such a standard. This may constitute a project which might be accredited and traded in terms of United Nations protocols. Electrical energy consumption in South Africa continues to grow at a rate which may necessitate that new generating capacity is on stream by 2007. It is shown that improvements in the energy efficiency of upper income houses will reduce the demand for electricity during peak hours. It is proposed that the progression of shack dwelling families to energy efficient formal housing, in conjunction with an appliance switch to more fuel efficient energy sources, will generate reductions in non-renewable coal and wood based fuel burning. As a result less localized air pollution will probably occur. In this study three types of house are analysed for their thermal comfort in hot and cold conditions. The energy efficiency and the affordability of heating these houses in winter is also investigated. The climatic variations between the regions of South Africa have been analysed in terms of the local thermal neutrality and indoor heating and cooling requirements. Criteria for measurement of comfort requirements and energy efficiency are developed. The ability of various thermal design measures necessary to effect thermal comfort and energy efficiency, has been analysed using the Building Toolbox software. The objective of the simulations was to maintain internal temperatures within the confines of local thermal neutrality with a minimum of heating. This methodology has given rise to the proposed intervention standards. The proposed standards and range of compliance methods will allow designers a high degree of flexibility. Architects will be able to make use of thermal mass, thermal insulation/resistance, variations in window size, etc. to achieve the required levels of energy efficiency. One proposed method of compliance check will be the so called Star Rating System. If properly promoted, the Star Rating System could lead to energy efficiency becoming an important attribute in the housing resale market. The results of an opinion survey among the members of the Thermal Insulation Association of South Mica (TIASA) indicated a high degree of consensus around the proposals. Comparison with the energy codes of foreign jurisdictions shows the proposals to be conservative. Given that power generating capacity will need to be expanded, it must be expected that electrical costs will escalate. This will effectively make such energy efficiency measures cheaper. In conclusion, it has been demonstrated that substantial reductions in carbon based energy consumption will take place if energy efficiency targets are to be built into the South African National Building Regulations. The standards which are proposed in this thesis will also bring about improvements in thermal comfort, productivity and the well-being of the entire community.
- ETD@PUK