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Faculty of Engineering and Built Environment

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Start date: 2021Subject: search.filters.subject.Energy efficiency

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Now showing 1 - 6 of 6
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    Appraisal and optimization of energy-efficient green buildings in South Africa
    (2024-05) Agbajor, Favour David; Mewomo, Modupe Cecilia
    Generally, over 35% of global energy use and 40% of carbon emissions are attributed to the built environment while future forecasts indicate that these values may rise much further. In South Africa (SA), building stocks account for 40% of the country’s final energy demand which strains the country's coal-dependent energy grid and oftentimes results in power outages. Optimizing energy efficiency and thermal comfort while attaining the lofty goal of carbon neutrality is essential for all concerned stakeholders in the building sector globally. Meanwhile, green building (GB), being a recognized revolutionary theory and practice in the building industry, is suggested as a solution to SA’s environmental challenges. On this wise, this research aimed to develop energy-efficient models for optimizing green buildings into the design and operation of buildings to allay their environmental impacts. The goal was to enhance energy efficiency, decrease energy consumption, and mitigate carbon emissions across diverse climates, thus benefiting South Africa's built environment. To achieve the study's goals, three primary research objectives were identified and pursued namely: (i) To provide an overview on status-quo of green building development in South Africa with a view to explore the status quo and provide roadmap for improvement; (ii)To examine the energy-saving potential of incorporating building-integrated greenery systems towards climate-resilience in the subtropical climate zone of South Africa; and (iii) To investigate the energy-performance of green building renewable energy utilization systems within South Africa’s hot and arid climate zones. Initially, the study's first objective entailed a comprehensive literature overview integrating climate, sustainability, and building energy modeling within the South African context. This was carried out through a scoping review approach via the PRISMA guideline of reporting Subsequent objectives involved selecting reference buildings and creating hypothesized models as case studies based on six climate zones from the South African National Standard. For the second objective, a thorough and integrative approach that linked building energy modelling and varying climatic change was devised. The numerical parametric simulation and analysis, being a quantitative research approach was adopted as a data collection method. Similarly, the third objective employed numerical parametric simulation as a data gathering method in this research, which is based on a quantitative analysis to explore various design options iteratively. In the second and third objectives, Global climate databases, Meteonorm, Climate Consultant, and energy simulation software such as DesignBuilder, EnergyPlus, and Polysun were used for weather data analysis, climate modeling, and building energy simulation. The findings highlighted that while South Africa boasts notable green construction projects, scientific research progress has not matched international levels. The focus was on promoting green building adoption through standards, certifications, and incentives. However, gaps were observed in optimized energy performance and post-occupancy evaluation of existing buildings. Despite high awareness, the utilization of green building technologies among South African professionals did not meet anticipated levels. For the second objective, the study's findings indicated an increase in extreme heat waves with higher peak temperatures in the future. Building energy use in the study area is projected to rise by 8-24% from 2030 to 2080. Notably, heat gains primarily result from envelope thermal transfer rather than solar radiation. Greenery systems were found to effectively support green building goals and urban sustainability across anticipated seasons. Nature-based solutions proved successful in adapting to climate change compared to non-retrofitted conventional buildings. For the last objective, the study revealed regions with substantial solar irradiance, indicating potential for renewable energy adoption. It emphasized the need for durable BIPV systems in hightemperature conditions. BIPV modules generated more energy in Upington than Nelspruit due to varying solar radiation. Opportunities were identified for BIPV systems to achieve optimal power generation. The study provides a foundation for informed decision-making, policy formulation, and targeted research in sustainable building practices. The study presents practical principles to guide urban planners and policymakers in integrating eco-friendly technology into both new and existing building designs. This promotes sustainable urban development and reduces cities' carbon emissions. Going forward, to showcase the effectiveness of these energy-efficient and climate-responsive systems to the public and industry stakeholders, it is recommended to establish and enhance largescale demonstration projects in South Africa's subtropical, hot and arid regions.
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    An energy efficient resource provisioning scheme for joint all photonic and wireless networks
    (IEEE, 2022-08-04) Molefe, Mlungisi; Nleya, Bakhe
    Flexible joint all photonic and wireless transport networks are a promising backbone network technological solution to accommodate the various dynamic bandwidth natured applications. In this paper, we mitigate methods aimed at maximizing available resources in a joint-photonic and wireless transport network in an energy-efficient manner. In so doing, we take into account challenges posed by transmission impairments as they tend to degrade signals and reduce their optical reach. We thus propose a state-of-the-art and innovative network architecture that can efficiently process a large amount of data. This architecture is designed to cater for bandwidth-hungry and bandwidth-dynamic applications and services. We further propose a load aware energy efficient resource optimization scheme using LERA algorithm, which couples with related service reconfiguration functions to maximize higher spectral efficiencies and minimal blocking in both optical and wireless sections of the composite network. Performance analysis shows that the proposed architectural scheme based on the LERA algorithm outperforms traditional benchmark techniques in achieving minimal blocking while efficiently maximizing spectral utilization compared to legacy benchmark approaches. Hence this scheme drastically enhances the utilization of the available resources and the overall network throughput.
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    An energy efficient resources allocation scheme for flexible translucent optical transport networks
    (Psychology and Education, 2021-03-02) Nleya, Bakhe; Molefe, Mlungisi; Chidzonga, Richard
    The present study attempts to explore how academic streams and learning styles play role in the preferences of coping strategies among prospective teachers. A quantitative approach was selected to explore the relationship. A survey was conducted with 300 prospective teachers (150 of science stream and 150 of humanities stream). A multi-stage random sampling technique was used to collect relevant information. Research instrument to measure coping strategies was developed by the researcher himself and Learning Style Inventory (LSI) by Ritu Dangwal & Sugata Mitra, 1997 was used to measure learning styles of prospective teachers. Statistical techniques i.e. mean, S.D., multivariate ANOVA were applied. Results revealed an essential significant effect of academic streams and learning styles on preference of coping strategies among prospective teachers. It is recommended that teacher training institutions should establish guidance or counseling centers to provide counseling to prospective teachers regarding coping skills and learning styles
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    An energy-efficient impairment-aware routing algorithm for optical transport networks
    (IEEE, 2021-03) Molefe, Mlungisi; Nleya, Bakhe; Chidzonga, R.; Bopape, Lebogang; Sibiya, K.
    Flexible Translucent optical Transport networks have the capability to provision multiple data rate demands much more efficiently than the traditional wavelength routed optical backbone networks. By design, in order to suffice the signal reach constraint, traditional optical networks also include several repeaters that are located sparsely along each signal path so as to facilitate successful end-to end transmission of those lightpath connection signals that otherwise would exceed the optical reach. The presence of physical impairments coupled with the inclusion of repeaters that facilitate signal amplification, timing and refreshing means more overall operational power requirements. Thus, energy efficient operation of flexible Translucent Optical Transport Networks is quite crucial. Thus, in this paper we propose a combined physical impairments-aware as well as energy-efficient available network resources allocation algorithm that bases on path availability, considering the impact of energy consumption minimization versus quality of transmission (QoT). We consider the impact of physical impairments in the formulation of the algorithm. We carry out simulation validations of the proposed algorithm which generally indicate to an improvement of energy efficiency as well as other key network resources utilization.
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    Privacy and security for applications and services in future generation smart grids
    (2022-05-13) Khumalo, Zephania Philani; Nleya, B.
    Growing energy demands together with the urge to supply available power in a reliable, as well as efficient manner, has led to the gradual upgrading and modernizing of existing power grid systems into Smart Grids (SGs) by way of incorporating supporting information and communication technology (ICT) subsystems. The latter facilities the two-way flow of both energy (power) and information related to the grid's performance, as well as the end user's requirements. Notably, the ICT subsystem enables key entities such as generation, distribution, transmission, and end-user subsystems to interrelated in real-time, and in the process, this achieving a well reliable, robust as well as efficiently managed SG system. The interactions of the various entities constituting the grid result in the emergence of various services and applications exchanging data throughout the interconnected systems. Whereas the SG is quite efficient in rendering its services, it, however, is exposed to various cyber security threats by adversaries. Notably, security threats vary depending on the applications. On the user end networks, the mandatory aggregation of power consumption as well as exchange of power consumption-related information on individual household area networks (HANs) or among HANs and utility's control canter (CC) can result in adversaries tempering with the processes. In particular key security concerns being that during these operations, individuals' privacy, as well as aggregated data integrity, can be compromised as a result of attacks. The resource-constrained nature of associated devices, objects, and elements of the SG at the user side networks and in the SG core, in general, brings about challenges in implementing robust security measures that inevitably involve the performing of complex crypto-operations.
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    Comparative analysis of specific energy consumption and energy consumption benchmarking in galvanising plants
    (IEOM Society International, 2022-08-04) Dewa, Mendon
    The inadequacy of sustainable energy is endlessly posing major challenges globally. The issue of energy optimisation is indispensable for manufacturing sector, particularly for a hot-dip galvanising process where galvanising furnaces are the significant energy users. This study is aimed at comparative analysis of specific energy consumption and energy consumption benchmarking in four galvanising plants with the view to necessitate the identification of best practices. Energy baselines were used as quantitative reference points to compare energy performance indicators and quantify fluctuations in energy performance during the baseline and reporting periods. A quantitative analysis was also conducted to benchmark four galvanising facilities on factors that included the electricity/zinc ratio, electricity /dips ratio and product tonnage/zinc used ratio. The results revealed improved performance for plant 4 over time relative to the baseline consumption when compared to plants 1, 2 and 3. Plant 4 also outperformed other facilities after the energy efficiency interventions in terms of electricity/zinc ratio and electricity/ product tonnage ratio. Given the disparity between the results of specific energy consumption (SEC) for the four plants, it was concluded that SEC alone should not be used as an energy performance indicator.