Conference Proceedings (Electrical and Electronic Engineering)

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Browsing Conference Proceedings (Electrical and Electronic Engineering) by Author "Booysen, M. J."

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    Evaluation of the energy model of a horizontally-mounted electric water heater through internal temperature measurement
    (Institute of Electrical and Electronics Engineers, 2017) Leeuwner, L. L.; Naude, N. H.; Roux, M.; Booysen, M. J.
    The resource-constraint energy sector faces an insatiable demand for energy, which necessitates improvements in efficiency. One key sector that has potential for savings is residential water heating, which makes up 32% of household energy. Previous studies have proven that with effective scheduling up to 29% savings can be achieved for a nominal consumption pattern. The model that was used to estimate the savings, calculates the energy usage for a given hot water consumption pattern and given heating schedule for a horizontally mounted water heater. This two-node model is used to aid user-informed scheduling and auto- scheduling, but was developed as a black-box model, validating the energy and not the internal temperatures, which could be misleading. This paper evaluates the accuracy of the model by performing temperature measurements inside the horizontal electric water heater. Moreover, two aspects neglected by the model are investigated: The node state transfer usage threshold, and the inter-nodal thermal resistance. The results show that the model significantly underestimates the stratification that occurs naturally. This underestimation also severely affects the modelled energy consumption and hides limitations of the model, preferring a lower threshold and higher inter-nodal resistance. The results also show that Legionella growth in the EWH could be a concern despite a high set point.
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    Presentation of a home automation solution with potential for seamless integration and vast expansion
    (2014-12) Sawyer, G.; Booysen, M. J.
    ENGLISH ABSTRACT: The ever-increasing existence of electronic systems and devices within the residential environment, along with the human desire to simplify life and daily routine, is generating increased interest in the field of Home Automation and intelligent environments. A large variety of HA solutions have been conceptualised or developed. However, many of these solutions are designed by experts and therefore require professionals to install and/or operate them. Furthermore they lack the potential for seamless integration into an already functioning home environment. This paper presents a HA solution with seamless integration potential. The system can be installed and configured without professional skills or physical alteration of the environment itself. There is also large potential for the expansion of the systems capabilities and functions due to the hardware and software platforms utilised. This paper concludes with an analysis of performance tests results, and a discussion of the potential avenues for expansion.
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    Saving on household electric water heating : what works best and by how much?
    (Institute of Electrical and Electronics Engineers, 2017) Nel, P. J. C.; Booysen, M. J.; Van der Merwe, B.
    Electric heating of water for domestic use is a substantial component of total household energy costs. Thermal energy in a water heater is either used (as warm water) or lost to the environment. Various approaches to reduce the losses and improve the efficiency of these notoriously inefficient and costly water heaters have been proposed and are employed. However, given the complex factors at play, making sense of the savings approaches and choosing the right one for the right use case is not a simple task and often misunderstood. This paper addresses this problem by comparing some of the commonly employed approaches, including schedule control, change in set temperature, use of thermal insulation, and reduction in consumed volume. We also compare the impact of environmental factors, such as changing the ambient temperature around the water heater and the cold inlet temperature. The results show that for the consumption profiles and use cases evaluated, schedule control is the most effective, followed by insulation of the tank and piping. Combined, these two interventions save up to 25%. We also find that the effect of the temperature of the cold inlet water dwarfs that of the ambient temperature, is in line with other approaches, and means the installation status quo needs to be reconsidered.