This report includes development of an already designed solar water heater. The product shall be constructed in a way that it will suit a manufacturing line in Kampala, Uganda. To find the most suitable design for each area a research was carried out which included study visits, interviews and background reading. It provided the following results: Regarding the attachment of in- and outgoing pipes from the water tank many methods were taken into consideration and it was found that the best and most suitable way for this case is to weld the fittings using a weld robot. Regarding the fitting of the acrylic, a suitable solution is to make a flange when vacuum forming the plastic casing to further support the design. This could also be used to waterproof the case by using a sealing material. A suggestion of using pre-molded PU-foam is also presented. Regarding the ability to open the case for maintenance, two solutions were recommended. Either the use of spire clips or having the clips integrated into the casing. Regarding the calculation of material usage when deep drawing the tank and collector, it is possible to do a reasonably accurate assumption. The complicated design in this product makes the estimation less accurate. It is recommended that test draws are done and often the machine producer has more precise numbers. Regarding the coloring of the collector; chemical coloration is not possible on a galvanized surface. The method used is painting, either with powder coating or with wet paint.

In Cape Town, South Africa, households' acces to modern and clean energy services needs to be increased. However, use of coal-powered electricity stresses the environment and power cuts create an urgent need to reduce the demand. Solar water heaters (SWH) could enable increasing access and affordability of energy services in the townships without stressing the environment or increasing the demand for coal-powered electricity. However, it is an expensive solution and the majority of the city-level efforts still target the high-consuming households. The benefits for the poor households from using a SWH could though outweigh the high capital investements and meet the needs of the city's environmental management. The results from this study of 20 households showed that by having an affordable, clean and reliable source of energy for heating water, households were able to use more warm water for bathing and reduce their use of electricity and paraffin. This resulted in improvements in health and quality of life. Also, households' general spending on energy was reduced, which for some enabled an increase in income-generating activities. The use of solar-heated showers was found to be restricted by the issue of sharing and it is argued that the benefits would be greater if each households had their own solar water heater. The estimated increase in water use might raise questions of the solution's future feasibility. Despite this, it can be argued that the changes in the households' energy and water use are likely to result in significant improvements in the households' well-being which could also benefit the city as a whole.

Developing nations face insurmountable challenges to reliably and sustainably provide energy and water to the population. These resources are intricately entwined such that decisions on the use of one affects the other (energy-water nexus). Inadequate and ageing infrastructure, increased population and connectivity, urbanization, improved standards of living and spatially uneven rainfall are some of the reasons causing this insecurity. Expanding and developing new supply infrastructure is not sustainable due to sky high costs and negative environmental impact such as increased greenhouse gas emissions and over extraction of surface water. The exponentially increasing demand, way above the capacity of supply infrastructure in most developing countries, requires urgent mitigation strategies through demand side management (DSM). The DSM strategies seek to increase efficiency of use of available resources and reducing demand from utilities in the short, medium and long term. Renewable energy, rooftop rain water harvesting, pump-storage scheme and grey water recycling are some alternatives being used to curb the insecurity. However, renewable energy and rooftop water harvesting are spasmodic in nature hampering their adoption as the sole supply options for energy and water respectively. The built environment is one of the largest energy and water consuming sectors in the world presenting a huge potential towards conserving and increasing efficiency of these resources. For this reason, coupled with the 1970s energy challenges, the concept of green buildings seeking to, among other factors, reduce the consumption of energy and water sprung up. Conventionally, policy makers, industry players and researchers have made decisions on either resource independently, with little knowledge on the effect it would have on the other. It is therefore imperative that optimal integration of alternative sources and resource efficient technologies are implemented and analysed jointly in order to achieve maximum benefits. This is a step closer to achieving green buildings while also improving energy and water security. A multifaceted approach to save energy and water should integrate appropriate resource efficient technology, alternative source and an advanced and reliable control system to coordinate their operation. In a typical South African urban residential house, water heating is one of the most energy and water intensive end uses while lawn irrigation is the highest water intensive end use occasioned by low rainfall and high evaporation. Therefore, seamless integration of these alternative supply and most resource intensive end uses provides the highest potential towards resource conservation. This thesis introduces the first practical and economical attempt to integrate various alternative energy and water supply options with efficient devices. The multifaceted approach used in this research has proven that optimal control strategy can significantly reduce the cost of these resources, bring in revenue through renewable energy sales, reuse waste water and reduce the demand for grid energy, water and waste water services. This thesis is generally divided into cold and hot water categories; both of which energy-water nexus DSM is carried out. Open-loop optimal and closed-loop model predictive (MPC) control strategies that minimize the objective while meeting present technical and operational constraints are designed. In cold water systems, open-loop optimal and MPC strategies are designed to improve water reliability through a pump storage system. Energy efficiency (EE) of the pump is achieved through optimally shifting the load to off-peak period of the time-of-use (TOU) tariff in South Africa. Thereafter, an open-loop optimal control strategy is developed for rooftop rain water harvesting for lawn irrigation. The controller ensures water is conserved by using the stored rain water and ensuring only the required amount of water is used for irrigation. Further, EE is achieved through load shifting of the pump subject to the TOU tariff. The two control strategies are then developed to operate a grey water recycling system that is useful in meeting non-potable water demand such as toilet flushing and lawn irrigation and EE is achieved through shifting of pump's load. Finally, the two control strategies are designed for an integrated rain and grey water recycling for a residential house, whose life cycle cost (LCC) analysis is carried out. The hot water category is more energy intensive, and therefore, the open-loop optimal control strategy is developed to control a heat pump water heater (HPWH) and an instantaneous shower, both powered by grid-tied renewable energy systems. Solar and wind energy are used due to their abundance in South Africa. Thereafter, the MPC strategy is developed to power same devices with renewable energy systems. In both strategies, energy is saved through the use of renewable energy sources, that also bring in revenue through sale of excess power back to the grid. In addition, water is conserved through heating the cold water in the pipes using the instantaneous shower rather than running it down the drain while waiting for hot water to arrive. LCC analysis is also carried out for this strategy. Each of the two control strategies has its strengths. The open loop optimal control is easier and cheaper to implement but is only suitable in cases where uncertainties and disturbances affecting the system do not alter the demand pattern for water in a major way. Conversely, the closed-loop MPC strategy is more complicated and costly to implement due to additional components like sensors, but comes with great robustness against uncertainties and disturbances. Both strategies are beneficial in ensuring security and reliability of energy and water is achieved. Importantly, technology alone cannot have sustainable DSM impact. Public education and awareness on importance of energy and water savings, improved efficiency and effect on supply infrastructure and greenhouse gas emissions are essential. Awareness is also important in enabling the acceptance of these technological advancements by the society. / Thesis (PhD)--University of Pretoria, 2017. / National Hub for Energy Efficiency and Demand Side Management (EEDSM) / University of Pretoria / Electrical, Electronic and Computer Engineering / PhD / Unrestricted

Water heating in a typical home in the U.S. accounts for a significant portion (between 14% and 25%) of the total home's annual energy consumption. The objective of considerably reducing the home's energy consumption from the utilities calls for the use of onsite renewable energy systems. Integral Collector Storage (ICS) solar domestic water heating systems are an alternative to help meet the hot water energy demands in a household. In order to evaluate the potential benefits and contributions from the ICS system, it is important that the parameter values included in the model used to estimate the system's performance are as accurate as possible. The overall heat loss coefficient (Uloss) in the model plays an important role in the performance prediction methodology of the ICS. This work presents a new and improved methodology to determine Uloss as a function of time in an ICS system using a systematic optimal control theoretic approach. This methodology is based on the derivation of a new nonlinear state space model of the system, and the formulation of a quadratic performance function whose minimization yields estimates of Uloss values that can be used in computer simulations to improve the performance prediction of the ICS system, depending on the desired time of the year and hot water draw profile. Simulation results show that predictions of the system's performance based on these estimates of Uloss are considerably more accurate than the predictions based on current existing methods for estimating Uloss.

Os sistemas prediais de aquecimento de água são responsáveis por uma parcela significativa no consumo de energia do país, sendo que a eficiência do uso desta energia está relacionada com a qualidade dos projetos e de alternativas construtivas que possibilitam racionalizar o uso dos recursos naturais. Com a tendência de incorporação da medição individualizada de água e do aquecimento solar, algumas concepções de projetos hidráulicos foram alteradas, entre elas, a introdução de sistemas centrais coletivos de aquecimento de água no setor residencial. Porém, os métodos de dimensionamento destes sistemas são restritos à determinação do estado estático da infraestrutura e dos equipamentos envolvidos. Conhecendo as características de uso da população é possível introduzir sistemas de monitoração e gestão que alterem o dimensionamento das centrais de aquecimento, conforme a demanda instantânea, gerando reduções de perdas térmicas. Este trabalho consiste em analisar as variáveis de um sistema predial de aquecimento central a gás e o impacto na implantação de sistemas de monitoração e gestão. / The building systems of water heating are responsible for a significant parcel of energy consumption in country, and the efficiency of use of this energy is related to the quality of projects and constructive alternatives that allow rationalizing the use of natural resources. With the trend of incorporating the measurement of individual water and solar heating, some conceptions of hydraulic projects were changed including the introduction of collective central heating water in the residential sector. However, the methods of these systems are restricted to the determination of the static state of infrastructure and equipment involved. Knowing the characteristics of populations use is possible to introduce systems of monitoring and management to change the design of central heating as the instant demand, causing reductions in thermal losses.

Os sistemas prediais de aquecimento de água são responsáveis por uma parcela significativa no consumo de energia do país, sendo que a eficiência do uso desta energia está relacionada com a qualidade dos projetos e de alternativas construtivas que possibilitam racionalizar o uso dos recursos naturais. Com a tendência de incorporação da medição individualizada de água e do aquecimento solar, algumas concepções de projetos hidráulicos foram alteradas, entre elas, a introdução de sistemas centrais coletivos de aquecimento de água no setor residencial. Porém, os métodos de dimensionamento destes sistemas são restritos à determinação do estado estático da infraestrutura e dos equipamentos envolvidos. Conhecendo as características de uso da população é possível introduzir sistemas de monitoração e gestão que alterem o dimensionamento das centrais de aquecimento, conforme a demanda instantânea, gerando reduções de perdas térmicas. Este trabalho consiste em analisar as variáveis de um sistema predial de aquecimento central a gás e o impacto na implantação de sistemas de monitoração e gestão. / The building systems of water heating are responsible for a significant parcel of energy consumption in country, and the efficiency of use of this energy is related to the quality of projects and constructive alternatives that allow rationalizing the use of natural resources. With the trend of incorporating the measurement of individual water and solar heating, some conceptions of hydraulic projects were changed including the introduction of collective central heating water in the residential sector. However, the methods of these systems are restricted to the determination of the static state of infrastructure and equipment involved. Knowing the characteristics of populations use is possible to introduce systems of monitoring and management to change the design of central heating as the instant demand, causing reductions in thermal losses.

This research investigates the use of an alternate means of modelling the performance of a train of feed water heaters in a steam cycle power plant, using machine learning. The goal of this study was to use a simple artificial neural network (ANN) to predict the behaviour of the plant system, specifically the inlet bled steam (BS) mass flow rate and the outlet water temperature of each feedwater heater. The output of the model was validated through the use of a thermofluid engineering model built for the same plant. Another goal was to assess the ability of both the thermofluid model and ANN model to predict plant behaviour under out of normal operating circumstances. The thermofluid engineering model was built on FLOWNEX® SE using existing custom components for the various heat exchangers. The model was then tuned to current plant conditions by catering for plant degradation and maintenance effects. The artificial neural network was of a multi-layer perceptron (MLP) type, using the rectified linear unit (ReLU) activation function, mean squared error (MSE) loss function and adaptive moments (Adam) optimiser. It was constructed using Python programming language. The ANN model was trained using the same data as the FLOWNEX® SE model. Multiple architectures were tested resulting in the optimum model having two layers, 200 nodes or neurons in each layer with a batch size of 500, running over 100 epochs. This configuration attained a training accuracy of 0.9975 and validation accuracy of 0.9975. When used on a test set and to predict plant performance, it achieved a MSE of 0.23 and 0.45 respectively. Under normal operating conditions (six cases tested) the ANN model performed better than the FLOWNEX® SE model when compared to actual plant behaviour. Under out of normal conditions (four cases tested), the FLOWNEX SE® model performed better than the ANN. It is evident that the ANN model was unable to capture the “physics” of a heat exchanger or the feed heating process as a result of its poor performance in the out of normal scenarios. Further tuning by way of alternate activation functions and regularisation techniques had little effect on the ANN model performance. The ANN model was able to accurately predict an out of normal case only when it was trained to do so. This was achieved by augmenting the original training data with the inputs and results from the FLOWNEX SE® model for the same case. The conclusion drawn from this study is that this type of simple ANN model is able to predict plant performance so long as it is trained for it. The validity of the prediction is highly dependent on the integrity of the training data. Operating outside the range which the model was trained for will result in inaccurate predictions. It is recommended that out of normal scenarios commonly experienced by the plant be synthesised by engineering modelling tools like FLOWNEX® SE to augment the historic plant data. This provides a wider spectrum of training data enabling more generalised and accurate predictions from the ANN model.

This thesis deals with design of hot water grate boiler, where the output is water with parameters 130 °C and pressure 16 bar. In the content of the whole thesis is gradually introduced a stoichiometric calculations, which is based on the specified fuel – wood chips. This is followed by the design of the individual heating surfaces according to the thermal calculations given in the thesis. Finally, the calculation is extended by hydraulic and aerodynamic losses. Dimensional design, as a basic scheme, is shown at thesis. More detailed drawing documentation is attached to this thesis.

The work generally deals with the possibilities of preparing hot water in household and analyzes saving posibilities. At the beginning of work the history of hot water preparation is briefly indicated. Chapter 3 deals with different ways of heating. Described in more detail electric storage heating is in chapter 4, where can be found the effect of heating to the power network, especially to the daily load diagram. The following are the information of the tariff policy, as a tool for motivation of consumers, for using the storage heating. In the next part, beginning with the fifth chapter, is written about the possibility of energy saving by means of intelligently controlled boiler. That eliminates the disadvantage of storage heating, which are the tank thermal losses. Heating is based on a certain regularity in the behaviour of the user and manages the preparation of water according to expected consumption. The sixth chapter then contains design of own algorithm for economical control of heating and also energetic and economic assessment of potential savings.

This diploma thesis describes the detailed design of heating and hot water heating for a family quest-house. At first the reader is introduced to the designed building, its design and construction elements. The thesis presents the calculation procedure and design of the heating system. This consists of designing radiators, the heat source, the circulating pumps, regulations of the heating system and the design of its security elements. The thesis also describes the design of the heat exchanger for hot water and security. In conclusion, an evaluation of operating costs with the recommended solution for their reduction. The thesis also includes drawing documentation of structural drawings, heating and unrolled schema that is mentioned in the attachment.