SUNScholar - Browsing by Author "Booysen, M. J."

Browsing by Author "Booysen, M. J."

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A comparative evaluation of the impact of average speed enforcement (ASE) on passenger and minibus taxi vehicle drivers on the R61 in South Africa
(South African Institution of Civil Engineering, 2016) Akoku Ebot Eno Akpa, Nelson; Booysen, M. J.; Sinclair, M.
Average speed enforcement (ASE) is an emergent alternative to instantaneous speed limit enforcement to improve road safety, and is used to enforce an average speed limit over a road segment. This paper presents a study on the response of passenger vehicles and minibus taxis to ASE on the R61 in South Africa. A spatio-temporal quantitative study of speed compliance was conducted, where metrics such as speed variability, average speed and 85th percentile speed measured prior to, and during enforcement, were analysed for two prominent modes of transport - passenger vehicles and minibus taxis. These measurements were taken on the enforcement route and on control routes adjacent to and further away from the enforcement route. A qualitative study was also conducted to evaluate the relationship between speed compliance and driver understanding of the system. The impact of the system on crash risk and injury severity was also examined before and during enforcement. For passenger vehicles, results showed that the introduction of ASE was followed by a reduction in mean speed on the enforcement route and adjacent control route. For minibus taxis, it was found that ASE appears to have little influence on improving speed compliance, which is likely associated with a lack of driver understanding of how the system operates.
A computationally inexpensive energy model for horizontal electric water heaters with scheduling
(2016-03) Nel, P. J. C.; Booysen, M. J.; Van der Merwe, A. B.
ENGLISH ABSTRACT: Electric water heaters (EWHs) remain one of the main contributors to energy consumption in countries where they are used. EWH models serve as a step towards achieving optimised control, and can also be used to inform users of expected savings due to changes, if the model is energy-based. Various models have been proposed, but none of them include more than half of the six key features that the model presented in this paper supports: horizontal orientation; schedule control; low computational complexity; validation of the model; multinodal stratification; and multinodal standing losses. The presented model is validated against six datasets: four comprising 900 hours with multiple water usage events; and two with only standing losses. The results show that the model estimates energy consumption over ten days including usage with an error of less than 2% and 5% for schedule control and thermostat control respectively. The simulation model is simple enough to execute ten days of simulation in less than 100 milliseconds on a standard desktop machine, 150 times faster than a prominent model from literature, making it also suitable for large scale simulations or for use on mobile devices.
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.
Factors that influence the geometric detection pattern of vehicle-based licence plate recognition camera systems
(Southern African Transport Conference, 2018-07) Rademeyer, M. C.; Booysen, M. J.; Barnard, A.
Licence plate recognition (LPR) systems are used to automatically extract the characters from licence plates positioned in front of a camera. The geometric detection pattern is the region within which the system can accurately recognise licence plates and is of special interest when the system is mounted in a moving vehicle. In this research, the theory surrounding camera optics was investigated and used as the basis of a software simulation model. Inspired by the simulation measurements, a real-world experimental test was conducted to further explore the influence various factors have on the geometric detection pattern. Analysis of these measurements provided greater insight how multiple factors individually contribute to the shape and size of the geometric detection pattern and serves as a guide in the design of vehicle-based LPR systems.
A potential source of undiagnosed Legionellosis : Legionella growth in domestic water heating systems in South Africa
(Elsevier, 2018-12-02) Stone, W.; Louw, T. M.; Gakingo, G. K.; Nieuwoudt, M. J.; Booysen, M. J.
ENGLISH ABSTRACT: Legionella is a genus of pathogenic bacterial mesophiles that cause a range of diseases collectively referred to as Legionellosis, with immunocompromised individuals being particularly susceptible. Water heaters, a potential domestic niche for these pathogens, are heavy energy consumers, causing cost-sensitive users to employ energy-saving initiatives, such as scheduling and lower temperature set points. However, lower heated water temperatures allow Legionella to ourish. This paper uses computational uid dynamics modelling to show that the pipes downstream of a horizontal electric water heater provide an environment that is conducive to Legionella growth, not the heater itself. The presence of Legionella in water heaters is established through water sampled from ve in- eld water heaters, of which the temperatures and heating schedules are known. Microbiological techniques (PCR and weight-based qRT-PCR) are used to assess Legionella and L. pneumophila presence at point-of-use taps. A model is used to determine the potential infection rate from these concentrations, demonstrating that undiagnosed Legionellosis infection is likely. In low- and middleincome countries, like South Africa, misdiagnosis of Legionellosis may be common due to the shadow cast by HIV and TB prevalence.
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.
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.
Simulating The Driving and Charging of Electric Minibus Taxis: A Case Study for Stellenbosch
(IWACP, 2023) Pretorius, B. G.; Strauss, J. M.; Booysen, M. J.
The Global North is increasing the drive for the electrification of the mobility industry. In sub-Saharan Africa, however, the adoption is yet to pick up steam due to various other challenges in the region. The viability of converting the paratransit fleet (which consists mostly of minibus taxis) to electric vehicles (EVs) with current combustion-based operations is investigated by making use of simulation software, and EV-Fleet-Sim. This developed software simulates the driving and charging of operationally tracked taxis in the Stellenbosch area. A charging algorithm, as well as a simple battery model, was included in the simulation to provide a more accurate representation of the scenario. Most of the taxis were found to still complete their required trips with the specified battery size of 70 kWh. However, new methods would need to be found, such as including a mixed fleet with some petrol or diesel taxis, to assure a 100% trip completion rate. The grid impact per vehicle was found with an expected maximum load appearing between the hours of 08h00 and 10h00 of 22 kW per vehicle, which corresponds to the time after the morning peak traffic of getting people to work. Furthermore, a minimum number of chargers can be implemented which will not affect the trip completion rate of the taxis. This was found to be for 4 chargers per 17 taxis. Future work is left to the testing of various parameters to find optimal solutions as well as including home charging and failed trip classification.
Temporal case study of household behavioural response to Cape Town's Day Zero using smart meter data
(Elsevier, 2018-11-13) Booysen, M. J.; Visser, M.; Burger, R.
ENGLISH ABSTRACT: Faced with the threat of "Day Zero", when it was feared that Cape Town's taps could run dry, consumers reduced household water usage from 540 to 280 litres per household per day over the 36 months between January 2015 and January 2018. This paper describes the events that prompted this reduction. We look at how changes in water use were a ected by o cial announcements and by public engagement with this news via the social media activity and internet searches. We analysed the water usage of a subset of middle to high income households where smart hot and cold water meters were installed. For hot water usage patterns we compared meter readings with that in another area una ected by the drought. We further map our cold water smart meter readings against that of the City of Cape Town's municipal data for domestic freestanding households | a sample of more than 400,000 households. We found that the introduction of Level 5 restrictions had a perverse e ect on consumption, possibly due to confusing messages. The most dramatic change in behaviour appears to have been instigated by a media storm and consequent user panic after the release of the City's CriticalWater Shortages Disaster Plan in October 2017. However, contradictory communication from national and provincial government eroded some of this gain. The paper concludes with recommendations for demand management in a similar future scenario.

Browsing by Author "Booysen, M. J."

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