School of Architecture and Planning

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Browsing School of Architecture and Planning by Author "Analo, Andrew"

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    Assessing the energy performance gap between 6-star and net-zero energy buildings for South Africa
    (2022) Analo, Andrew
    Energy efficiency in buildings has been systematically coupled with the green-rating of buildings based on systems such as the Star-rating of the Green Building Council of South Africa (GBCSA). Net-zero energy buildings (NZEBs) have also been receiving increased attention as a way of addressing concerns over depleting energy resources (especially for fossil fuels), increasing energy-costs and greenhouse gas (GHG) emissions which contribute to global warming and climate change. With a focus on reduction in contribution to GHG-emissions and thus enhancing climate change mitigation of 6-Star green-rated buildings the study applied a case-study approach based on energy performance of the Department of Environmental Affairs (DEA) Building in Pretoria. Secondary data show that the building’s status quo energy performance is 112kWh/m2/yr. Within the temperate-interior climatic zone for Pretoria (as per energy efficiency regulations for buildings in South Africa), psychrometric chart analysis showed that the building could achieve a higherlevel of thermal comfort through further optimization of passive design interventions. Edge-tool simulation results on full optimization of passive design and energy efficiency interventions indicate that a net-zero energy building (NZEB) performance of the same sized building could achieve an energy performance level of 45kWh/m2/yr, thus revealing an energy performance gap of 67kWh/m2/yr. This translates to 60% savings compared to the status quo 6-Star performance of 3076 291kWh/year. Assessment of roof-area for solar PV system indicated that it is adequate for the energy balance towards a NZEB. Assessment of simple payback period per intervention indicates less than one-year payback period for tenant lighting while tenant equipment indicatesa payback period of just over a year and PV-installation at three-years. The findings indicate that the intervention-costs for migration to NZEB fall within the acceptable range for South African investors (maximum of 3 to 5 years). The above findings indicate that the pursuit of NZEBs would significantly contribute towards mitigation of GHG-emissions and climate change and thus calls for further exploration of pathways towards mandatory NZEBs for South Africa.