Increased consumer demand for fresh fruit throughout the year has created a need for long term storage. Long term storage of fruit uses more energy than fresh market products, thus increasing production cost. Pacific Northwest energy costs and more competition for markets has made energy conservation an important factor to be considered by the fruit industry. A BASICA computer program, RLSIM, was developed to predict the transient refrigeration load throughout the storage season in apple and pear cold storage warehouses. RLSIM accurately predicted the seasonal and component refrigeration system energy demand curves during the 1985-1986 cold storage season. The results also indicated that the largest single energy use component is the continuous operation of evaporator fans. Simulation of a six hours on and six hours off fan cycling technique indicated a reduction of 23.75 percent could be achieved in overall refrigeration system energy use in the cold storage warehouse. Cold storage warehouse management can be improved by using the results of RLSIM. Fan cycling schemes could be properly employed without risk of increasing fruit temperature. Recommendations were made to update research in areas of cooling and respiration rates of various fruits in both controlled atmosphere and common storage. / Graduation date: 1988

M.A. (Environmental Management) / The Small Micro Medium Enterprise (SMME) sector plays a critical role in the economy of South Africa by reducing poverty and providing employment. South Africa has about 6 million SMMEs that employ more than 61% of citizens and contribute about 37% to the Gross Domestic Product (GDP). The growth and development of the sector over the years has however been compromised and threatened by the shortage of electricity and increasing electricity tariffs. Whereas large companies can manage to afford the adoption of energy efficiency measures in order to reduce energy costs, SMMEs have limited resources and may therefore struggle to afford energy efficiency adoption. However, there is a lack of scientific documentation about energy efficiency adoption amongst manufacturing SMMEs (M-SMMEs) in South Africa. The purpose of the research is to therefore assess the state of energy efficiency adoption amongst M-SMMEs, despite the challenges they experience. To achieve this research goal, the study surveyed and characterised the extent of energy efficiency adoption and also unveiled the drivers and barriers to energy efficiency adoption. Data were collected by means of surveys, making use of questionnaires. A sample of 30 firms was selected for the research. Almost all (96%) firms perceived EE as an opportunity. However, only 50% had adopted EE measures. Key drivers to adoption included the motive to reduce production costs, mitigate the impact of increasing electricity prices, gain competitive advantage and payback period. The gap between EE perception and adoption was caused by several barriers like the lack of finance, skills and time. Among non-adopters, 60% indicated their willingness to be trained in EE. The study therefore recommends improved capacity building through workshops for M-SMMEs.

Call number: LD2668 .T4 1986 R43 / Master of Science / Biological and Agricultural Engineering

M.Tech. (Architectural Technology) / It is estimated that commercial buildings are responsible for 5.4% of worldwide Green House Gas (GHG) emissions through their construction and on-going operation. In developed countries this figure can go up to 30%. The environmental control industry is one of the large consumers of this energy. Heating, ventilation and air conditioning (HVAC) contribute approximately 15% of South Africa's current peak electrical demand consumption according to Eskom (the South African electricity utility). The purpose of this dissertation is to analyse and evaluate methods to reduce the energy consumption of the HVAC system in a commercial office building. This encompasses careful building design to reduce heat loads and promote the circulation of fresh air; the use of energy-efficient air-conditioning systems and the incorporation of materials and technology to reduce energy consumption. This will be based upon a case study of the new SANRAL (South African National Roads Agency Limited) head office building in Val-DeGrace, Pretoria. A deductive research approach will be followed. The as-designed Actual Building is modelled with the appropriate energy modelling software and its annual energy usage is obtained. A benchmark based Notional Building complying with SANS 204:2008 criteria of the same size, shape, location and operational schedules as the Actual Building is also modelled and its energy usage results compared to that of the Actual Building. This comparison will determine how energy efficient the Actual Building's HVAC system is compared to a conventional Notional Building. Quantitative data collection is performed by empirical measurement of the energy usage of the as-built Actual Building. The raw data (power usageofthe HVAC system) is measured by Schneider Electric PM9c™ power meters located in the HVAC distribution boards of the building. This raw data are collected by Schneider Electric's ION Enterprise' power management software which has a user friendly interface from where the data can be downloaded. The power management software is connected to an ANDOVEWM Building Management System (BMS). Due to commissioning procedures and the timeframe at hand for the completion of this dissertation measurements could only be taken over a 7 month period. Operational data were measured from July 2011 to March 2012 thus accounting for summer, winter and a seasonal changeover period. The modelled energy usage results of the as-designed Actual Building are compared to the measured energy usage data obtained from the as-built Actual Building. This comparison serves to evaluate the accuracy of the software model...

M. Tech. (Power Engineering, Faculty of Engineering and Technology), Vaal University of Technology / In view of the energy consumption problems, an impact study, extensive laboratory tests and an investigation towards comparable energy saving light sources was carried out on the light sources identified in the survey conducted at the Vaal University of Technology (VUT), Vanderbijlpark campus. Three types of identified incandescent light sources were purchased and extensively tested in order to obtain viable statistical data on the life span, luminance delivered per unit, power consumption and economic effect, as well as identifying relevant energy efficient light sources for replacement purposes. A suitable computerised maintenance program has been developed to be introduced to the VUT that currently does not have a lighting system maintenance program. The case study was located within the empirical-analytical paradigm, using quantitative data. The identified aims and goals place the empirical part of the study in the category of implementation evaluation research that provides an overview of a maintenance plan.

This thesis presents a complete method of modeling the autospectra of turbulence in closed form via an expansion series using the von Kármán model as a basis function. It is capable of modeling turbulence in all three directions of fluid flow: longitudinal, lateral, and vertical, separately, thus eliminating the assumption of homogeneous, isotropic flow. A thorough investigation into the expansion series is presented, with the strengths and weaknesses highlighted. Furthermore, numerical aspects and theoretical derivations are provided. This method is then tested against three highly complex flow fields: wake turbulence inside wind farms, helicopter downwash, and helicopter downwash coupled with turbulence shed from a ship superstructure. These applications demonstrate that this method is remarkably robust, that the developed autospectral models are virtually tailored to the design of white noise driven shaping filters, and that these models in closed form facilitate a greater understanding of complex flow fields in wind engineering. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.

Made available in DSpace on 2016-04-04T18:31:36Z (GMT). No. of bitstreams: 1 Inacio Henrique Yano.pdf: 6983897 bytes, checksum: 8c6efaa78bd069aef49c797811885285 (MD5) Previous issue date: 2012-12-19 / Wireless Sensor Networks are networks suitable for data collection in harsh environments, where it would be difficult or costly the deployment of wired infrastructure. In spite of these advantages, such networks often rely on batteries to operate, which may lead to a serious limitation on the networks lifetime. Bearing this in mind, in this dissertation, it is proposed and tested a hybrid polling approach that reduces the number of frames transmitted by the router node. Thus, the router node lifetime can be extended significantly and hence the network lifetime. The proposed technique becomes progressively more advantageous, when compared to classical polling technique, as the number of network nodes increases. The experimental results obtained using a network with four nodes indicate a network lifetime increase of about 32.14%. Importantly, the sensor network lifetime extension increases the economic viability of the technology and thus makes it more accessible to potential users. / Redes de Sensores Sem Fio s?o redes pr?prias para a coleta de dados em ambientes agressivos, de dif?cil acesso ou de alto custo de implanta??o de infraestrutura cabeada. Apesar destas vantagens, tais redes muitas vezes dependem de baterias para funcionar, o que pode acarretar uma s?ria limita??o em seus tempos de opera??o. Em fun??o disso, neste trabalho, desenvolveu-se uma estrat?gia para o prolongamento do tempo de vida de redes de sensores, mediante a aplica??o de uma estrat?gia de polling h?brida que permite reduzir a quantidade de quadros transmitidos pelo n? roteador. Desta forma, pode-se estender significativamente o tempo de vida do n? roteador e, consequentemente, a vida da rede. A t?cnica proposta torna-se progressivamente mais vantajosa, quando comparada a t?cnica de polling cl?ssico, conforme aumenta-se o n?mero de n?s da rede. Os resultados experimentais obtidos com uma rede com quatro n?s indicam uma amplia??o do tempo de vida em cerca 32,14%. ? importante notar que a extens?o do tempo de vida da rede de sensores amplia a viabilidade econ?mica da tecnologia e, portanto, a torna mais access?vel a potenciais usu?rios.

Este estudo analisa a Resposta da Demanda (DR da sigla em inglês para Demand Response) e a Geração Distribuída Fotovoltaica (GDFV), visando o desenvolvimento de uma abordagem para modelá-las como recursos para o planejamento energético. A metodologia inclui o uso de uma prática típica de preço de energia no varejo como a Tarifa pelo Horário de Uso (THU) para DR de consumidores residenciais e o sistema de compensação de energia elétrica (net metering) para a microgeração distribuída provida por sistemas Fotovoltaicos (FV) do tipo rooftop. A metodologia proposta foi aplicada a um estudo de caso com diferentes níveis de DR e/ou GDFV, baseado no IEEE 8500-Node Test Feeder, com uma subestação de distribuição e 1177 consumidores em baixa tensão, utilizando-se o Open Distribution System Simulator (OpenDSS) para a solução do fluxo de potência e a obtenção de dados de demanda, consumo de energia, perdas e tensões. Os níveis mais elevados de DR e GDFV, em dia útil, em um grupo de Consumidores Residenciais Responsivos (CRR) cuja carga representa 26,6% da carga total do circuito de teste, resultaram em 6,3% de redução na demanda de ponta da subestação, 9,6% de redução no consumo diário de energia da subestação e 13,3% de redução nas perdas diárias de energia nas linhas e transformadores, comparando-se com o caso base com a tarifa convencional, sem DR e GDFV, e mantendo-se o consumo diário de energia dos CRR. Uma análise de sensibilidade foi realizada por meio de variações aleatórias nas curvas de carga dos consumidores e, nos cenários aplicáveis, na irradiância no plano inclinado e na temperatura dos conjuntos FV, respeitando uma distribuição normal. O estudo de caso foi complementado com a avaliação das variações na conta de energia de amostras de CRR, cujas maiores reduções, comparando-se com o caso base, foram 36,3% com os níveis mais elevados de DR e GDFV e 37,6% com os níveis mais elevados de GDFV e sem DR, indicando uma situação na qual mudanças regulatórias seriam necessárias para estimular DR e GD simultaneamente, como no caso da THU opcional chamada de tarifa branca no Brasil. A quantificação do potencial de DR e GDFV pode indicar tendências para o planejamento energético, contribuir para planos de eficiência energética e possibilitar a implementação de sistemas modernos e sustentáveis nos quais os consumidores possam participar de forma mais ativa. / This study analyses the Demand Response (DR) and Photovoltaic Distributed Generation (PVDG) for developing an approach to model them as resources for energy planning. The methodology includes the use of a typical retail pricing practice such as the Time-of-Use Tariff (TOU) for residential consumers\' DR and net metering for distributed micro-generation provided by rooftop Photovoltaic (PV) systems. The proposed methodology was applied to a case study with different levels of DR and/or PVDG, based on the IEEE 8500-Node Test Feeder, with a distribution substation and 1177 low-voltage consumers, using the Open Distribution System Simulator (OpenDSS) to obtain the power flow solution and demand, energy consumption, losses and voltages data. The highest levels of DR and PVDG on weekday in a group of Responsive Residential Consumers (RRC) whose load represents 26.6% of the total load in the test circuit resulted in 6.3% reduction in the substation peak demand, 9.6% reduction in the substation daily energy consumption and 13.3% reduction in the daily energy losses in lines and transformers, compared to the base case with flat tariff, without DR and PVDG, and maintaining the daily energy consumption of RRC. A sensitivity analysis was performed using random variations in load curves and, in the applicable scenarios, in plane-of-array irradiance and PV array temperature curves, using a normal distribution. The case study was complemented with the analysis of energy bill variations of samples of RRC, whose greatest reductions compared to the base case were 36.3% with the highest levels of DR and PVDG and 37.6% with the highest level of PVDG and without DR, indicating a situation in which regulatory changes would be necessary to stimulate DR simultaneously with PVDG, such as in the case of the optional TOU called white tariff in Brazil. The quantification of DR and PVDG potential can show trends to energy planning, contributes to energy efficiency plans and enables the implementation of modern and sustainable systems in which end users can participate more actively.

Creating a diverse and flexible energy system to ensure security of supply is at the heart of UK energy policy. However, despite the apparent interest in the idea of securing supply in this way and the term ‘diversity' becoming more frequently used in this context in government White Papers, policy discourse and the academic literature relatively little attention has been given to exploring what diversity means, how it can be measured, what contribution it can make to different policy objectives and the specific implications for the UK electricity system. Furthermore CCS technologies which are becoming increasingly important to decarbonisation of the power sector in order to meet legally binding greenhouse gas targets set out in the Climate Change Act which raises the question, what are the potential impacts of these technologies on the diversity of the future UK electricity system? To answer this question a mixed methodology of quantitative energy-economic modelling (using MARKAL), scenario analysis and diversity analysis is combined with qualitative semi-structured stakeholder interviews. Data analysis is carried out in two parts. The first assesses the diversity (with a specific focus on the effect of different input assumptions on CCS technologies) of the scenarios generated using Stirling's Diversity Heuristic and creates a set of ‘diversity profiles' which map changes in diversity across each scenario. The second part uses stakeholder perspectives to inform the quantification of diversity across the same set of scenarios providing evidence of the impact of different stakeholder perspectives on the overall diversity of the electricity system.

Este estudo analisa a Resposta da Demanda (DR da sigla em inglês para Demand Response) e a Geração Distribuída Fotovoltaica (GDFV), visando o desenvolvimento de uma abordagem para modelá-las como recursos para o planejamento energético. A metodologia inclui o uso de uma prática típica de preço de energia no varejo como a Tarifa pelo Horário de Uso (THU) para DR de consumidores residenciais e o sistema de compensação de energia elétrica (net metering) para a microgeração distribuída provida por sistemas Fotovoltaicos (FV) do tipo rooftop. A metodologia proposta foi aplicada a um estudo de caso com diferentes níveis de DR e/ou GDFV, baseado no IEEE 8500-Node Test Feeder, com uma subestação de distribuição e 1177 consumidores em baixa tensão, utilizando-se o Open Distribution System Simulator (OpenDSS) para a solução do fluxo de potência e a obtenção de dados de demanda, consumo de energia, perdas e tensões. Os níveis mais elevados de DR e GDFV, em dia útil, em um grupo de Consumidores Residenciais Responsivos (CRR) cuja carga representa 26,6% da carga total do circuito de teste, resultaram em 6,3% de redução na demanda de ponta da subestação, 9,6% de redução no consumo diário de energia da subestação e 13,3% de redução nas perdas diárias de energia nas linhas e transformadores, comparando-se com o caso base com a tarifa convencional, sem DR e GDFV, e mantendo-se o consumo diário de energia dos CRR. Uma análise de sensibilidade foi realizada por meio de variações aleatórias nas curvas de carga dos consumidores e, nos cenários aplicáveis, na irradiância no plano inclinado e na temperatura dos conjuntos FV, respeitando uma distribuição normal. O estudo de caso foi complementado com a avaliação das variações na conta de energia de amostras de CRR, cujas maiores reduções, comparando-se com o caso base, foram 36,3% com os níveis mais elevados de DR e GDFV e 37,6% com os níveis mais elevados de GDFV e sem DR, indicando uma situação na qual mudanças regulatórias seriam necessárias para estimular DR e GD simultaneamente, como no caso da THU opcional chamada de tarifa branca no Brasil. A quantificação do potencial de DR e GDFV pode indicar tendências para o planejamento energético, contribuir para planos de eficiência energética e possibilitar a implementação de sistemas modernos e sustentáveis nos quais os consumidores possam participar de forma mais ativa. / This study analyses the Demand Response (DR) and Photovoltaic Distributed Generation (PVDG) for developing an approach to model them as resources for energy planning. The methodology includes the use of a typical retail pricing practice such as the Time-of-Use Tariff (TOU) for residential consumers\' DR and net metering for distributed micro-generation provided by rooftop Photovoltaic (PV) systems. The proposed methodology was applied to a case study with different levels of DR and/or PVDG, based on the IEEE 8500-Node Test Feeder, with a distribution substation and 1177 low-voltage consumers, using the Open Distribution System Simulator (OpenDSS) to obtain the power flow solution and demand, energy consumption, losses and voltages data. The highest levels of DR and PVDG on weekday in a group of Responsive Residential Consumers (RRC) whose load represents 26.6% of the total load in the test circuit resulted in 6.3% reduction in the substation peak demand, 9.6% reduction in the substation daily energy consumption and 13.3% reduction in the daily energy losses in lines and transformers, compared to the base case with flat tariff, without DR and PVDG, and maintaining the daily energy consumption of RRC. A sensitivity analysis was performed using random variations in load curves and, in the applicable scenarios, in plane-of-array irradiance and PV array temperature curves, using a normal distribution. The case study was complemented with the analysis of energy bill variations of samples of RRC, whose greatest reductions compared to the base case were 36.3% with the highest levels of DR and PVDG and 37.6% with the highest level of PVDG and without DR, indicating a situation in which regulatory changes would be necessary to stimulate DR simultaneously with PVDG, such as in the case of the optional TOU called white tariff in Brazil. The quantification of DR and PVDG potential can show trends to energy planning, contributes to energy efficiency plans and enables the implementation of modern and sustainable systems in which end users can participate more actively.