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First–principles studies on the development of semiconductor–based photocatalyst materials for applications in photocatalytic water splitting and degradation of pollutants

- Opoku, Francis

An experimental and computational investigation of a hybrid photovoltaic and solar thermal cell

- Cieslakiewicz, Waldemar

The selection of renewable energy technologies and their cost implications for a developing country : the case of South Africa

- Pillay, Sedge

  • Authors: Pillay, Sedge
  • Date: 2016
  • Subjects: Renewable energy sources - South Africa , Renewable energy sources - Developing countries , Sustainable development - Developing countries , Solar energy
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/225239 , uj:22744
  • Description: Abstract: Renewable energy technologies have to be considered and appropriately supplemented in the energy mix. For this mini-dissertation, particular emphasis will be focusing on the developing nation of South Africa. Research previously conducted has indicated there are specific key criteria to consider for selecting sustainable energy methods, particularly for renewable energy technologies in Africa. Within this mini-dissertation consideration is given to renewable energy methods for generating power in South Africa from selected viewpoints that consist of political, social, technical, economic and environmental impact. With the aid of the Analytic Hierarchy Process (AHP), this particular mini-dissertation will allow for selecting and prioritizing various renewable technologies for power generation. Potential for electricity generation was accessed from renewable resources, reviewing of relevant scholarly literature and discussion with experts; an appropriate decision-model has been utilised consisting of goal, criteria, sub-criteria and alternatives. Onshore wind energy, solar photovoltaic, concentrated solar thermal, biomass and small hydro energy options are used as the alternatives in the decision model. The mini-dissertation makes use of a real-world case study within South Africa, to apply the decision-model, build upon previous research and showcase its value in energy planning. In addition to prioritisation and ranking of these alternatives to show the best technology will be that of solar energy for the South African market; results of the proposed decision model can also be used to advocate in developing specific policies and energy roadmaps for the country. , M.Ing. (Engineering Management)
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The impact of slow uptake of renewable energy in South Africa with emphasis on the solar energy type systems

- Mncube, Innocent Mduduzi

  • Authors: Mncube, Innocent Mduduzi
  • Date: 2015
  • Subjects: Solar energy , Renewable energy sources
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/56132 , uj:16334
  • Description: Abstract: The dissertation examines the slow uptake of renewable energy in South Africa, especially solar type energy systems. It aims to identify and understand the issues and the unique dynamics involved in the local government (municipalities) since they are at the forefront of electricity distribution. The dissertation takes a qualitative research approach and a triangulation of data collection methods, combined with a relatively broad literature study to capture the complexity of the related issues. The contextual focus includes the macro-economic factors that contribute to the environment in which municipalities operate, developmental, economic, political and social aspects and the related experience of poverty, urbanization and unemployment. Furthermore, the dissertation attempts to show that a relationship exists between a slow uptake of renewable energy technologies, particularly solar energy and the loss of electricity sales revenue by municipalities in recent times. Key findings indicate that the electricity sales revenue of municipalities is affected by the introduction of renewable energy technologies. This in turn causes reluctance in promoting such technologies from the decision makers at municipal level, because electricity distribution income is a key contributor to municipal revenue without which municipalities will not be able to meet their constitutional obligations. These findings are supported by the view of this dissertation when comparing electricity sales revenue of metropolitan municipalities over the past five years and also studying municipal legal framework. A variety of related theoretical work is chosen in this dissertation as a useful framework for analysis in order to approach issues of comparing the relationship between depleting municipal electricity sales revenue and the slow uptake of the renewable energy type system with a major focus on solar energy. , M.Ing. (Engineering Electrical and Electronics)
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Technological feasibility and cultural acceptability study of solar power systems for microwave assisted sandstone artisanal mining

- Agwa-Ejon, J. F., Mulaba-Bafubiandi, A. F., Pretorius, J. H.

  • Authors: Agwa-Ejon, J. F. , Mulaba-Bafubiandi, A. F. , Pretorius, J. H.
  • Date: 2015-08-06
  • Subjects: Artisinal mining - South Africa - QwaQwa , Sandstone - South Africa - QwaQwa , Microwave energy , Solar energy
  • Type: Article
  • Identifier: uj:5218 , http://hdl.handle.net/10210/14504
  • Description: This paper investigates the technical feasibility of microwave assisted artisanal mining in the production of Sandstone from QwaQwa in South Africa. It further discusses the cultural acceptability by the rural community of the synergetic application of the emerging technology (microwave energy) and the renewable resource (solar). Sandstone in QwaQwa, Free State is artisanally mined using chisels and hammers. This form of mining is extensively laborious and is normally accompanied by numerous casualties. The paper demonstrates the existence and the possible utilization of alternative methods including emerging technologies which are more productive, efficient, effective and sustainable. The solar energy systems are used to trigger the microwave magnetron which results into high energy microwave dosage. The dosage causes differential or selective heating on the rocks which culminate into rock breaking along the interfacial grain boundaries between the different constituting minerals. The data used in the analysis was collected by administering questionnaires to the artisanal mining community in QwaQwa and from observations made on site as well as desk top information obtained from secondary sources. The paper contributes to knowledge by drawing on the solar energy systems to generate the dosage required to trigger the microwave magnetron used to facilitate a more efficient and economical artisanal mining of sandstones. In conclusion the paper recommends to policy makers the application of microwave energy in mineral artisanal mining and processing instead of the manual chisel and hammer currently being utilized country wide. It then gives a detail analysis of the technical, scheduling and economic analysis of the sandstone artisanal mining in QwaQwa.
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Characterization of QwaQwa sandstones and design of solar powered microwave cutter equipment for artisanal mining

- Mubiayi, Mukuna Patrick

  • Authors: Mubiayi, Mukuna Patrick
  • Date: 2012-10-24
  • Subjects: Solar energy , Sandstone mining , Artisanal mining , Rock mechanics
  • Type: Thesis
  • Identifier: http://ujcontent.uj.ac.za8080/10210/389808 , uj:10428 , http://hdl.handle.net/10210/7893
  • Description: M.Tech. , Artisanal mine of sandstones especially in rural area are facing numerous challenges including the use of inadequate tools for the processing of sandstones. Since the current processing technique has limitations which consist of the use of hammer and chisels, there is a need to develop environmentally friendly and cost effective techniques for the processing of sandstones. In this project, six different sandstones samples (yellowish, blackish, reddish, greenish, greyish and whitish) from QwaQwa rural area were collected and characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS) and an optical microscope. In addition, physical properties of sandstones were also carried out including compressive strength, dielectric properties and water absorption. Furthermore sandstones samples were irradiated using multi- and single- mode microwave cavities to investigate the effect on the mineralogy of sandstones. The analysis of mineralogical change was carried out using XRD. Additionally a microwave multimode cavity was used to investigate the weight loss of sandstones after being irradiated. A microwave cavity was designed based on the characteristics of sandstones and it was simulated. A photovoltaic solar system was sized to power the microwave cutter. The experimental work was carried out on a laboratory scale. The XRD analysis revealed that quartz was the major mineral present in all sandstones which confirms that QwaQwa sandstones are quartz based sandstones. Feldspar minerals such as illite and albite were also found. Additional minerals were identified at trace level including glauconite, kaolonite, crysobalite and orthoclase. On the other hand, the XRD results of the irradiated samples using a single- and multi- mode cavity for 60 seconds revealed a strong presence of quartz which means no significant changes were observed. However, some minor overlapped peaks suspected to be muscovite (KAl2(Si3Al)O10(OH,F)2) in three samples (blackish, greyish and yellowish) were noticed. XRF study showed that the chemical elements available in the six sandstones samples are: aluminium, calcium, iron, potassium, magnesium, manganese, sodium, phosphorus, silicon and titanium.
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Aerodynamic optimization in light weight solar vehicle design

- De Kock, Juan-Paul

Optimisation of electric long endurance unmanned aerial vehicles

- Fourie, Dehann

  • Authors: Fourie, Dehann
  • Date: 2012-06-06
  • Subjects: Solar powered aircraft , Drone aircraft , Sustained flight , Solar energy
  • Type: Thesis
  • Identifier: uj:2514 , http://hdl.handle.net/10210/4968
  • Description: M.Ing. , Sustained or long endurance solar powered flight is defined as an aircraft capable of main- taining flight through multiple day-night flight cycles, using only solar power and rechargable energy stores. The project is focused on developing solar powered flight theory and real-world unmanned aerial vehicle implementations. The important aspects of system design are es- tablished and studied at a fundamental theoretical level. A preliminary design is conducted with endurance optimisation as the main aim. The optimisation process aims to establish a theoretical basis for sustained solar powered flight. The project is started with a feasibility and relevance study. A literature study was used to gather the required theoretical information. A novel theoretical preliminary design basis is conducted. The study is aimed at answering many questions in the field. The study is the first to show how previously varied aircraft from 3 m to 80 m are valid solutions to the long endurance flight requirement. The optimisation results correlates well with the current state-of-the-art. The theoretical models were then characterised through the development of two unmanned aerial vehicles. The development required a multidisciplinary integration of various fields. The development process was characterised and discussed. Flight automation was successfully integrated into the system. Multiple test flights were conducted. An interpretation of multi- faceted results are given. This project has contributed to international theory regarding solar powered and sustained endurance aircraft. Many specific contributions were made to the field. The project has achieved multiple unofficial records from the flight tests in the Southern Hemisphere and African continent.
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Computer aided design of systems for solar powered water pumping by photovoltaics

- Lujara, Nelson Kakuru

  • Authors: Lujara, Nelson Kakuru
  • Date: 2012-08-23
  • Subjects: Photovoltaic power systems , Photovoltaic power generation , Solar energy , Computer-aided design
  • Type: Thesis
  • Identifier: uj:3116 , http://hdl.handle.net/10210/6537
  • Description: D.Ing. , Low system efficiency is a critical problem in photovoltaic (PV) applications due to low efficiency of solar cells. Despite this shortcoming, stand-alone PV systems, have proven to be economical and reliable choices in some applications such as telecommunications, vaccine refrigeration and water pumping in remote locations. In this study, CAD algorithms for the design of PV water pumping systems have been developed with the objective of maximizing the conversion efficiency from the solar irradiation to the potential energy of water by taking into account the variations in the pumping head. The study starts by developing loss models of various sub-systems in the photovoltaic dc and ac motor drive water pumping systems. Using MathCad, these models are then used in the simulation of the system. The simulation results are verified experimentally using their equivalent circuit configurations. The efficiency of the array, the pump and the motor are found to be the most critical parameters for the performance of the systems. The efficiencies of other components, such as the inverter, have also been shown to have a significant effect. The study has shown that for operation at the maximum power point, the inclusion of a maximum power tracker is necessary in a dc motor drive system but may be eliminated in PWM inverter-fed induction motor drive systems through proper matching of the system components. The study has further shown that matching of the drive system and the load with the insolation is essential, since maximum system efficiency occurs at a specific head, which varies as the insolation changes. Prior investigation of site insolation variations is therefore a critical requirement.
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Investigating the effects of composite materials in solar cell encapsulation

- Hurter, W., Oosthuizen, G., Janse van Rensburg, N.

  • Authors: Hurter, W. , Oosthuizen, G. , Janse van Rensburg, N.
  • Date: 2013
  • Subjects: Renewable energy resources , Solar energy , Solar cell encapsulation
  • Type: Article
  • Identifier: uj:4950 , http://hdl.handle.net/10210/13050
  • Description: In the past few decades our society’s increasing demands for energy have naturally resulted in increased utilization of renewable resources such as solar energy. Due to this strong demand the solar car endurance race was established to challenge researchers in this field. A competitive vehicle needs around six square meters of solar cells that produce approximately one kilowatt of power. This equates to 514 monocrystalline silicon half cells. The manufacturing challenge is to protect these cells from the terrestrial elements over a prolonged period of time. In this research study a composite encapsulation method was developed for solar cells and tested. Experiments were conducted to assess the processing of composite materials to improve the mechanical strength of the fragile solar cells. The effects of composites on reinforcement, electrical efficiency and thermal efficiency of the photovoltaic (PV) cells were evaluated. Impact testing to simulate a hailstone shows that the fibreglass sandwich panel structure will protect the surface of the cells, whilst reducing their efficiency by less than 5%.
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An investigation into the thermo-fluid design and technical feasibility of a practical solar absorption refrigeration cycle

- Santos, Nelson de Sousa Pedro dos

  • Authors: Santos, Nelson de Sousa Pedro dos
  • Date: 2010-03-15T06:30:41Z
  • Subjects: Solar energy , Photovoltaic power generation , Solar cells
  • Type: Thesis
  • Identifier: uj:6672 , http://hdl.handle.net/10210/3077
  • Description: M.Eng. , The need and problem was originated from the trends of the earths dwindling energy resource. As time progresses humans are becoming more aware of need to use so called “alternative energy sources” to alleviate the main energy converters i.e. power stations. The student was tasked with investigating the thermal performance of a solar powered refrigeration cycle (prototype) that could: produce enough refrigeration effect that it replaces the standard home vapour compression unit, used for cooling or freezing of foods, heats up a geyser sufficiently to have hot water for a common house hold, has excess energy to heat or cool liquid or air based environments and has the potential to lower the electrical bill of a house. The introductory step was to obtain the thermo fluid properties of aqua ammonia solutions. A setback came about when determining the aqua ammonia properties. There were too many conflicting properties being yielded by six different authors. In an attempt to gain confidence in only one author a comparison table was prepared. The table compared the six authors to each other. By looking at all the values compared it brought great clarity to the problem. When continuing the research into the fundamental law approach of solving for the cycle new findings were made. Initially very little comprehensive studies were done which explained in fundamental laws to solve for the absorption cycle. After extensive reviewing of a detailed study on how to solve for absorption refrigeration cycles, then it was able to begin improving on the thermo – fluid design of the cycle. As cycle and component design began to progress the train of thought began to steer in a direction. Each component needed to be detail designed. The advantage of having each component specifically catered for in the cycle design was that it would increase the cycle efficiency. In this way it would ensure that during the concept generation phase the functioning of each component was clear, thereby enabling a clear understanding of how components would compliment each other in a cycle. A mode of solving for the cycle was to endeavour that all parameters could be calculated unambiguously, with the aid of computerisation. Testing was carried out on a real life commercial thermal siphoning machine in order to realistically understand how absorption refrigeration works and gain experience. At the end of the study the most important result is that the dissertation research shows strong evidence that it will be possible to create a device which can fulfil the four tasks listed above. Another result is a program which is a refined cycle design of the pump absorption type refrigeration. The program solves for points along the cycle. Lastly it was found that even though EES was the simpler program to use for aqua ammonia solution properties it was the only program which catered for sub cooling and super heating.
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Characterization and fabrication of nanostructured TiO2/NiO heterojunction solar cells

- Ukoba, Kingsley O., Jen, Tien-Chien

Comparison of experimental data and two clear sky models

- Guillou, P., Madyira, D. M., Marc, O., Akinlabi, Esther Titilayo

  • Authors: Guillou, P. , Madyira, D. M. , Marc, O. , Akinlabi, Esther Titilayo
  • Date: 2016
  • Subjects: CFD models , Fair weather condition , Solar energy
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/123918 , uj:20851 , Citation: Guillou, P. et al. 2016. Comparison of experimental data and two clear sky models.
  • Description: Abstract: Solar energy is becoming a key player in manufacturing especially for off-grid applications such as community factories. Between the radiation emitted by the Sun and that absorbed on Earth, different phenomena take place. Many models were developed to tackle and explain these phenomena with varying levels of accuracy and complexity. Two commonly used models in most commercial simulation software such as ANSYS® Fluent® are the Fair Weather Condition and Theoretical Maximum Method. The aim of this paper is to investigate the accuracy of these models based on experimentally measured data. While these models assume a completely clear sky, the study is based on wet season. Global irradiance data acquired for different hours (9 o'clock, 12 o'clock and 15 o'clock) of the day was used. Results show good correlation between the average global irradiance for the Fair Weather Condition and the experimental values. The accuracy is more important for high solar elevation around 12 o’clock.
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Novel approach for concentrating and harvesting solar radiation in hybrid transparent photovoltaic façade’s in Southern Africa.

- Gevers, R.H., Pretorius, J.H.C., Van Rhyn, P.

  • Authors: Gevers, R.H. , Pretorius, J.H.C. , Van Rhyn, P.
  • Date: 2016
  • Subjects: Transparent solar cell , Solar , Solar energy
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/91838 , uj:20152 , Citation: Gevers, R.H., Pretorius, J.H.C. & Van Rhyn, P. 2016. Novel approach for concentrating and harvesting solar radiation in hybrid transparent photovoltaic façade’s in Southern Africa.
  • Description: Abstract: Electrical consumption and the price thereof is rapidly increasing in South Africa. Finding alternatives to the current grid-tied electricity supply in the country is a prodigious concern to the South African economy due to historic unreliability. The national power grid and the South African economy can extensively benefit from utilizing solar energy as an abundant clean and renewable energy source. This paper considers and further investigates power generation utilising a novel approach to transparent solar façades (windows). Harvesting solar energy is consequently included in the building envelope, which improves building efficiency while reducing demand on the national electric grid. The impacts, design, modelling and results of this novel approach to Photo Voltaic (PV) systems, is further examined in this paper. These systems are aimed to be used in the commercial and residential market. Factoring in the location, design and installation of the solar façade, geographical conditions relevant to South Africa were used to evaluate the transparent façade’s performance. The generated power from a façade depends on solar irradiation, orientation, (Azimuth and Zenith angles); climate conditions such as temperature and rainfall; and other solar constraints. These factors were incorporated using average values from meteorological data.
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The selection of renewable energy technologies and their cost implications for a developing country : the case of South Africa

- Pillay, S., Pretorius, J.H.C., De Canha, D.

The modelling of solar radiation quantities and intensities in a two dimensional compound parabolic collector

- Moodaly, Asogan

  • Authors: Moodaly, Asogan
  • Date: 2010-03-15T06:30:19Z
  • Subjects: Solar radiation , Solar energy , Solar thermal energy , Solar collectors design and construction
  • Type: Thesis
  • Identifier: uj:6671 , http://hdl.handle.net/10210/3076
  • Description: M.Ing. , A dissertation presented on the basic solar design principles such as sun-earth geometry, energy wavelengths, optics, incidence angles, parabolic collector configurations and design, materials for solar applications, efficiencies, etc to be considered in Solar Concentrating Collector design. These principles were applied in the design and fabrication of a prototype solar collector. The solar collector was tested to verify and correct mathematical models that were generated from existing literature; as well as for optimization work.
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Energy efficiency model for induction furnace

- Dey, Asit Kr

  • Authors: Dey, Asit Kr
  • Date: 2018
  • Subjects: Voltage multiplier method , Foundry energy optimization , Solar energy
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/290673 , uj:31559 , Citation: Dey, A.K. 2018. Energy efficiency model for induction furnace.
  • Description: Abstract: In this paper, a system of a solar induction furnace unit was design to find out a new solution for the existing AC power consuming heating process through Supervisory control and data acquisition system. This unit can be connected directly to the DC system without any internal conversion inside the device. The performance of the new system solution is compared with the existing one in terms of power consumption and losses. This work also investigated energy save, system improvement, process control model in a foundry induction furnace heating framework corresponding to PV solar power supply. The results are analysed for long run in terms of saving energy and integrated process system. The data acquisition system base solar foundry plant is an extremely multifaceted system that can be run over an almost innumerable range of operating conditions, each characterized by specific energy consumption. Determining ideal operating conditions is a key challenge that requires the involvement of the latest automation technologies, each one contributing to allow not only the acquisition, processing, storage, retrieval and visualization of data, but also the implementation of automatic control strategies that can expand the achievement envelope in terms of melting process, safety and energy efficiency.
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Cloud for monitoring and logging solar energy and battery usage

- Mabunda, N.E., Joseph, Meera K.

  • Authors: Mabunda, N.E. , Joseph, Meera K.
  • Date: 2016
  • Subjects: DAS , Data acquisition , Solar energy
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/123296 , uj:20773 , Citation: Mabunda, N.E & Joseph, M.K. 2016. Cloud for monitoring and logging solar energy and battery usage.
  • Description: Abstract: Data Acquisition Systems (DAS) can be used to gather changing energy parameters derived from various energy sources. This paper discusses how Arduino based data acquisition systems (DAS) can be used to gather solar energy samples and battery level information for remote monitoring and storage in the cloud. Arduino code was developed on Arduino IDE. An open source third party application was used to capture the Arduino serial transmitted values onto a Dropbox folder where it can be shared via Internet. Arduino hardware is connected to the four small 5 V, 1 W solar panels that are loaded with properly calculated resistors and a designed battery level sensor circuit. Solar energy values and battery usage pattern values were successfully stored into Dropbox for monitoring via cloud.
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Die berekening van sonintensiteit en die simulasie van sonstand

- Botha, Hester Maria Johanna

  • Authors: Botha, Hester Maria Johanna
  • Date: 1987
  • Subjects: Solar energy
  • Language: Afrikaans
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/15777 , uj:15699
  • Description: Abstract: The purpose of the project was to calculate the intensity of the sun and to simulate the sun's altitude.A computer programme (including a correction factor for the effects of altitude) was written to calculate the values of the intensity of the sun and a heat exchanger was built to verify the results experimentally. Tests were done with the heat exchanger at right angles to the sun and the difference in temperature between the inlet and the outlet of the heat exchanger was used to calculate the intensity of the sun. A model was designed to simulate the suns altitude at any given time of the day and at any chosen place in the country... , M. Ing. (Mechanical Engineering)
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Design of a temperature controllable demand water heater

- Duff, Craig Andrew

  • Authors: Duff, Craig Andrew
  • Date: 2012
  • Subjects: Renewable energy sources , Hot-water supply , Solar energy , Heat exchangers
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/256890 , uj:26975
  • Description: Abstract: The purpose of this study is to investigate ways to reduce the wastage of electricity and water during domestic hot water applications. Contemporary electric water heaters do not use water and electricity in an efficient manner due to their methods of operation, the placement of the water heater unit away from the point‐of‐use and the lack of direct user‐control. The aim of this study is to consider the feasibility of decentralising water heating to the point‐of‐use by combining a compact heating chamber with the tap, providing scope for the user to be in direct control of the water heating system. This study is necessary in order to support the development of products that improve the efficient use of essential resources, in this case electricity and water. The method used to study the feasibility of user‐controlled decentralised water heating is laboratory‐based experimentation, for which a compact heating chamber and user‐operated controls are designed. This study uses mixed‐methods research to measure both the heating chamber and the user‐control simultaneously. The experimental findings confirm that it is possible to heat flowing water in a compact heating chamber and the user is able to directly control the water heating system. These findings support further research and development of the user‐controlled point‐of‐use water heating concept as a method to save electricity and water. Further research and development should aim to determine to what extent this concept saves water and electricity when compared to existing water heating systems. , M.Tech. (Industrial Design)
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