Thesis (MEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Solar Assisted Power Generation (SAPG) can be seen as a synergy of solar and fossil plants – combining the environmental benefits of the former and the scale, efficiency and reliability of the latter. SAPG offers great potential for cost effective utilization of solar energy on utility scale and could accelerate the adoption of solar thermal energy technologies in the short and medium term, especially in countries with a significant coal base and a good solar resource such as Australia, China, United States, India and South Africa. SAPG is the replacement of bled-off steam in a Regenerative Rankine power cycle. Power plant simulations were performed using weather data for Lephalale, South Africa (Matimba power station). With an increase in the solar field outlet temperature, an increase in overall solar to electric efficiency was observed, superior to a stand-alone Solar Thermal Power Plant(s) (STPP) at similar temperatures. The performance of four solar collector technologies was compared: flat plate, evacuated tube, Linear Fresnel (LF) and Parabolic Trough (PT). This comparison was limited to the normal incidence angles of irradiation. For this application, nonconcentrating technologies are not competitive. For non-normal incidence angles, annual simulations were limited to PT and LF at final feedwater heater temperatures. The actual aperture area of around 80 000 m2 was used (50 MW thermal based on LF). On an equal aperture area basis, PT outperforms LF significantly. For the conventional North-South arrangement, LF needs to be around 53% of the specific installation cost (in $/m2 aperture area) of PT to be cost competitive. A SAPG plant at Lephalale was compared to a stand-alone Solar Thermal Power Plant STPP in a good solar resource area, namely Upington, South Africa – Parabolic Trough solar collector fields of equal size were considered for both configurations. It was found that the annual electricity generated with a SAPG plant is more than 25% greater than a stand-alone STPP. If the cost of SAPG is taken as 72% of the cost of a stand-alone STPP, this translates into SAPG being 1.8 times more cost effective than stand-alone STPP. Furthermore, SAPG performs better in high electricity demand months (South African winter – May to August). Stand-alone STPP have been adopted in South Africa and are currently being built. This was achieved by the government creating an attractive environment for Independent Power Producers (IPP). Eskom, the national power supplier, is currently investigating solar boosting at existing Eskom sites. This report argues that on a national level, SAPG, specifically solar preheating of feedwater, is a more viable solution for South Africa, with both its significant coal base and good solar resource. / AFRIKAANSE OPSOMMING: Son ondersteunde krag generasie (SOKG) kan gesien word as sinergie van sonkrag en fossiele brandstof aanlegte – dit voeg die omgewings voordele van die eersgenoemde en die grote, effektiwiteit en betroubaarheid van die laasgenoemde by mekaar. SOKG opper groot potensiaal vir koste effektiewe gebruik van son energie op nutsmaatskappyskaal en kan die aanvaarding van sontermiese energietegnologieë in die kort en medium termyn versnel, veral in lande met beduidende kool reserwes en goeie sonkrag voorkoms soos Australië, China, Verenigde State van Amerika, Indië en Suid-Afrika. SOKG impliseer die vervanging van aftap stoom in die regeneratiewe Rankine krag kringloop. Kragstasie simulasies was gedoen met die gebruik van weer data van Lephalale, Suid-Afrika (Matimba kragstasie). Met die toename van die sonveld uitlaat temperatuur kon oorhoofse son-na-elektrisiteit effektiwiteit vasgestel word, wat hoër is as die van alleenstaande sontermiese krag stasie (STKS) by soortgelyke temperature. Die effektiwiteit van vier son kollekteerder tegnologieë was vergelyk: plat plaat, vakuum buis, lineêre Fresnel (LF) en paraboliese trog (PT). Die vergelyking was beperk tot normale inval van bestraling. Vir hierdie toepassing is nie-konsentreerende tegnologie nie mededingend nie. Vir nie-normale inval hoeke was jaarlange simulasies beperk tot PT en LF by finale voedingswater temperatuur. Die werklike opening area van omtrent 80 000 m2 was gebruik (50 MW termies gebaseer op LF). By gelyke opening area, uitpresteer PT LF beduidend. Vir die gebruiklike Noord-Suid rankskikking benodig LF omtrent 53% van die spesifieke installasie kostes (in $/m2 opening area) van PT om kostes mededingend te kan wees. ‘n SOKG aanleg by Lephalale was vergelyk met alleenstaande STKS in die goeie son voorkoms gebied van Upington, Suid-Afrika – Paraboliese trog kollekteerder velde van gelyke grote was oorweeg vir al twee konfigurasies. Dit was gevind dat die jaarlikse elektrisiteit gegenereer vanaf SOKG meer as 25% is as die van alleenstaande STKS. Indien SOKG oorweeg word met 72% van die kostes van alleenstaande STKS, dan beteken dit dat SOKG 1.8 keer meer koste effektief is as alleenstade STKS. Verder, SOKG presteer beter in die hoer elektrisiteitsnavraag maande (Suid- Afrikaanse winter – May tot Augustus). Alleenstaande STKS is gekies vir Suid-Afrika en word tans gebou. Dit is bereik deur dat die regering ‘n aantreklike omgewing geskep het vir onafhanglike krag produsente. Eskom ondersoek tans SOKG by bestaande Eskom persele. Hierdie verslag beweer dat op nasionale/Eskom vlak, SOKG, besonders son voorverhitting van voedingswater, meer haalbare oplossing is vir Suid-Afrika met sy beduidende koolreserwes en goeie son voorkoms.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-03-30T18:22:27Z No. of bitstreams: 1 Israel de Oliveira.pdf: 2249672 bytes, checksum: 651678b57093fe8cfdec97b6e6da1274 (MD5) / Made available in DSpace on 2015-03-30T18:22:27Z (GMT). No. of bitstreams: 1 Israel de Oliveira.pdf: 2249672 bytes, checksum: 651678b57093fe8cfdec97b6e6da1274 (MD5) Previous issue date: 2014-01-31 / JTI Processadora de Tabaco do Brasil Ltda / Programa de Bolsas de Estudo Talentos Tecnosinos / O Brasil é um dos maiores produtores mundiais de tabaco de estufa e a região sul é a maior responsável por essa produção, principalmente o estado do Rio Grande do Sul. Uma das etapas do processo de beneficiamento desse produto é a secagem (cura) das folhas, que utiliza essencialmente lenha como fonte de energia. Esse trabalho apresenta um estudo dos aspectos energéticos que envolvem a cura de tabaco da espécie Virgínia, os resultados e análises das simulações realizadas no software TRNSYS, de um sistema solar térmico com aquecimento de água para complemento energético desse processo de cura. A partir de dados experimentais obtidos em processos de cura, foram definidos os parâmetros mais importantes para a determinação da carga térmica necessária e calculadas as perdas térmicas envolvidas. Os resultados apresentados pelas simulações mostraram que o sistema de energia solar proposto, atuando como fonte auxiliar de energia em uma estufa do tipo bulk, é capaz de atender completamente a carga térmica da primeira fase do processo de cura e contribuir com o aumento da temperatura na estufa necessário à cura dessa espécie de tabaco, gerando reduções no consumo de lenha do processo da ordem de 18 a 39 %, considerando que esse ocorra em um período de sete dias ensolarados no verão, na região de Santa Cruz do Sul-RS. / Brazil is one of the largest barn tobacco producers and the southern region is largely responsible for this production, especially the state of Rio Grande do Sul. One of the steps involved in this product’s processing chain is the leaves drying (curing), which essentially uses firewood as energy source. This work presents a study of the energy aspects involving the curing of Virginia tobacco, the results and analysis of simulations, using the TRNSYS software, of a solar thermal energy system with water heating to complement this curing process. From the experimental data obtained in curing processes, the most important parameters for the determination of thermal load were defined and the heat losses involved were calculated. The results presented by these simulations showed that the proposed solar energy system, acting as an auxiliary power source of a bulk type barn, can completely meet the thermal load of the first phase of the curing process and contribute to the increase of temperature in the barn necessary to cure this kind of tobacco, reducing 18-39 % the firewood consumption in the process, assuming a seven sunny days period during the summer at the region of Santa Cruz do Sul – RS.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-15T13:18:20Z No. of bitstreams: 1 Fábio Ricardo de Oliveira de Souza.pdf: 10103280 bytes, checksum: 4e2fd0c8307348f7e9098749cafe8b73 (MD5) / Made available in DSpace on 2015-07-15T13:18:20Z (GMT). No. of bitstreams: 1 Fábio Ricardo de Oliveira de Souza.pdf: 10103280 bytes, checksum: 4e2fd0c8307348f7e9098749cafe8b73 (MD5) Previous issue date: 2013-01-31 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este trabalho apresenta um estudo numérico sobre características de escoamento e transferência de calor em tubo evacuado. A abordagem numérica foi realizada com o software comercial ANSYS-CFX. O modelo numérico adotado é tridimensional e é composto pelas equações da conservação da massa, quantidade de movimento e energia. A malha computacional é do tipo hexaédrica, com refinamento nas regiões de maiores gradientes térmicos e fluidodinâmicos. O modelo implementado foi validado com resultados numéricos da literatura e um estudo de caso foi realizado, considerando variações do ângulo de inclinação do tubo, da variação da taxa de transferência de calor para o tubo e da variação da temperatura da água proveniente do reservatório térmico. Também foram avaliadas duas hipóteses: uma considerando propriedades físicas da água constantes e a outra com propriedades variáveis com a temperatura. Comparações são apresentadas para campos de velocidade e temperatura, vazão mássica e números de Nusselt e de Reynolds. O comparativo entre os resultados obtidos com a hipótese de propriedades constantes, com aqueles obtidos com propriedades variáveis mostra diferenças significativas entre eles, apontando a importância do uso de propriedades variáveis neste tipo de simulação numérica. Os resultados dos estudos paramétricos indicam que o incremento da vazão mássica e da temperatura média de saída do fluido é diretamente proporcional ao incremento do ângulo de inclinação, da taxa de transferência de calor e da temperatura do reservatório térmico. / This work presents a numerical study on characteristics of flow and heat transfer in an evacuated tube. The numerical approach was performed with the commercial software ANSYS-CFX. The numerical model adopted is three-dimensional and consists of the mass, momentum and energy equations. The computational mesh is hexaedrical, with refinement in regions of higher thermal and fluid gradients. The implemented model was validated with numerical results of literature and a case study was conducted considering inclination angle, rate of heat transfer and water temperature from the thermal reservoir. Also were evaluated two hypotheses: one considering constant physical properties of water and the other with properties varying with temperature. Comparisons are presented for velocity and temperature fields, mass flow and Nusselt and Reynolds numbers. The comparison between the results obtained with the hypothesis of constant properties, with those obtained with variable properties, shows significant differences between them, pointing out the importance of using variable properties in this type of numerical simulation. The results of the parametric studies indicate that the increment of the mass flow and average temperature of the fluid is directly proportional to the inclination angle, the rate of heat transfer and the temperature of the thermal reservoir.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-20T14:17:58Z No. of bitstreams: 1 Ronaldo Bueno de Souza.pdf: 1999281 bytes, checksum: 5dd2b3645a9e4750a12f291e30ba6d41 (MD5) / Made available in DSpace on 2015-07-20T14:17:58Z (GMT). No. of bitstreams: 1 Ronaldo Bueno de Souza.pdf: 1999281 bytes, checksum: 5dd2b3645a9e4750a12f291e30ba6d41 (MD5) Previous issue date: 2015-04-07 / CYTED - Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo / Este trabalho apresenta o estudo de um sistema de refrigeração por absorção assistido por energia solar térmica com intuito de ser empregado no arrefecimento de uma pousada de ecoturismo localizada em um local remoto, desprovida de conexão à rede elétrica. Para o estudo do sistema proposto foi utilizado o software de simulações TRNSYS, onde em uma etapa inicial do trabalho foi realizada a comparação dos resultados do software com os resultados dos modelos matemáticos dos componentes do sistema de refrigeração. Foi desenvolvido um modelo computacional, para realização de simulações horárias que permitiu a simulação de três configurações de sistemas de refrigeração por absorção, podendo assim determinar a influência dos componentes e parâmetros utilizados no sistema no uso da energia auxiliar e no atendimento da carga térmica. O primeiro modelo é constituído por um sistema onde a água aquecida pelo coletor solar térmico e é armazenada em um reservatório térmico, sendo a mesma utilizada para a alimentação do chiller de absorção. A água gelada produzida pelo chiller é armazenada em outro reservatório térmico onde fica disponível para o consumo. Neste modelo observa-se que com o uso de 120 m² de coletores de tubo evacuado chega-se a índices de atendimento dos consumos superiores a 87 %. O segundo modelo é similar ao primeiro, com a inclusão de um aquecedor auxiliar para a água de alimentação do chiller de absorção. Neste modelo observou-se que com o uso de 120 m² de coletores de placas planas chega-se a um consumo de energia auxiliar inferior a 195 GJ, e com o uso de 120 m² de coletores de tubo evacuado chega-se a um consumo de energia auxiliar inferior a 150 GJ. O terceiro modelo é similar ao segundo, onde foi acrescentado um sistema para utilização da água de arrefecimento do chiller de absorção, para uso no consumo de água quente para banho, nos chuveiros. Neste modelo observa-se que o aproveitamento da água de arrefecimento não afeta o consumo de energia auxiliar, se comparado com o consumo do segundo modelo. / This paper presents the study of a cooling system for absorption assisted by solar energy with a view to be used in the cooling of an ecotourism lodge located in a remote location, devoid of connection to the grid. To study the proposed system was used TRNSYS simulation software, where in an initial work step of comparing software results with the results of mathematical models of the components of the refrigeration system is performed. A computer model was developed to perform simulations slot which simulated three configurations absorption refrigeration systems and can therefore determine the influence of the components and system parameters used in the auxiliary power usage and meet the thermal load. The first model is made up of a system where the water heated by the solar thermal collector and is stored in a thermal storage tank, being the same used for feeding the absorption chiller. The chilled water produced by the chiller is stored in another thermal reservoir where it is available for consumption. In this model it is observed that with the use of 120 m² evacuated tube collectors comes to fuel consumption attendance rates of over 87 %. The second model is similar to the first, with the inclusion of an auxiliary heater to supply water from the absorption chiller. In this model we found that with the use of 120 m² of flat plate collectors comes to an auxiliary power consumption of less than 195 GJ, and with the use of 120 m² evacuated tube collectors we arrive at a consumption of auxiliary power less than 150 GJ. The third model is similar to the second, which was added to a system using the cooling water from absorption chiller for use in the consumption of hot water for baths, showers on. In this model, it is observed that the use of the cooling water does not affect the auxiliary power consumption compared with the consumption of the second model.

The thesis presents background on solar thermal energy and addresses the structural challenges associated with the deployment of concentrating solar power fields in urban areas. Two potential structural systems and urban locales of deployment are proposed and investigated to determine whether they have the potential to be a cost-effective renewable energy solution for urban areas. The structural issues explored in the thesis include flutter, the wind loading of open frame structures, performance-based design, and the design of flexibly mounted equipment on a building.

abstract: Recently, nanostructured metamaterials have attracted lots of attentions due to its tunable artificial properties. In particular, nanowire/nanohole based metamaterials which are known of the capability of large area fabrication were intensively studied. Most of the studies are only based on the electrical responses of the metamaterials; however, magnetic response, is usually neglected since magnetic material does not exist naturally within the visible or infrared range. For the past few years, artificial magnetic response from nanostructure based metamaterials has been proposed. This reveals the possibility of exciting resonance modes based on magnetic responses in nanowire/nanohole metamaterials which can potentially provide additional enhancement on radiative transport. On the other hand, beyond classical far-field radiative heat transfer, near-field radiation which is known of exceeding the Planck’s blackbody limit has also become a hot topic in the field. This PhD dissertation aims to obtain a deep fundamental understanding of nanowire/nanohole based metamaterials in both far-field and near-field in terms of both electrical and magnetic responses. The underlying mechanisms that can be excited by nanowire/nanohole metamaterials such as electrical surface plasmon polariton, magnetic hyperbolic mode, magnetic polariton, etc., will be theoretically studied in both far-field and near-field. Furthermore, other than conventional effective medium theory which only considers the electrical response of metamaterials, the artificial magnetic response of metamaterials will also be studied through parameter retrieval of far-field optical and radiative properties for studying near-field radiative transport. Moreover, a custom-made AFM tip based metrology will be employed to experimentally study near-field radiative transfer between a plate and a sphere separated by nanometer vacuum gaps in vacuum. This transformative research will break new ground in nanoscale radiative heat transfer for various applications in energy systems, thermal management, and thermal imaging and sensing. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2017

This study focused on a numerical second law analysis and optimisation of a receiver tube op- erating in a parabolic trough solar collector for small-scale application. The receiver functioned in a Rankine cycle. The focus was on entropy generation minimisation in the receiver due to the high quality exergy losses in this component. Water functioned as the working uid and was heated from ambient conditions (liquid) to a superheated state (vapour), consequently, the receiver tube was subject to both single phase as well as two-phase ow. Entropy generation in the receiver tube was mainly due to nite temperature di erences as well as uid friction. The contribution of each of these components was investigated. Geometrical as well as operating conditions were investigated to obtain good guidelines for receiver tube and plant design. An operating pressure in the range of 1 MPa (Tsat = 180 C) to 10 MPa (Tsat = 311 C) was considered. Furthermore a mass ow range of 0:15 kg=s to 0:4 kg=s was investigated. Results showed that beyond a diameter of 20 mm, the main contributor to the entropy generation was the nite temperature di erences for most conditions. Generally, operating pressures below 3 MPa showed bad performance since the uid friction component was too large for small operating pressures. This phenomenon was due to long two-phase lengths and high pressure drops in this region. The nite temperature di erence component increased linearly when the tube diameter was increased (due to the increase in exposed area) if the focused heat ux was kept constant. However, the uid friction component increased quadratically when the diameter was reduced. In general when the concentration ratio was increased, the entropy generation was decreased. This was due to more focused heat on each section of the receiver pipe and, in general, resulted in shorter receiver lengths. Unfortunately, there is a limit to the highest concentration ratio that can be achieved and in this study, it was assumed to be 45 for two-dimensional trough technology. A Simulated Annealing (SA) optimisation algorithm was implemented to obtain certain optimum parameters. The optimisation showed that increasing the diameter could result in a decrease in entropy generation, provided that the concentration ratio is kept constant. However, beyond a certain point gains in minimising the entropy generation became negligible. Optimal operating pressure would generally increase if the mass ow rate was increased. Finally, it was seen that the highest operating pressure under consideration (10 MPa) showed the best performance when considering the minimisation of entropy in conjunction with the maximisation of the thermodynamic work output. / Dissertation (MEng)--University of Pretoria, 2014. / tm2015 / Mechanical and Aeronautical Engineering / MEng / Unrestricted

Thesis (MScIng)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The Spier Estate - a wine estate in the Western Cape Province of South Africa - is engaged in a transition towards operating according to the principles of sustainable development. Besides changes in social and other environmental aspects, the company has set itself the goal to be carbon neutral by 2017. To this end, Spier is considering the on-site generation of electricity from renewable energy sources. This study was initiated to explore the technical and economic feasibility of a concentrating solar power plant for this purpose on the estate. The investigation was carried out to identify the most appropriate solar thermal energy technology and the dimensions of a system that fulfils the carbon-offset requirements of the estate. In particular, potential to offset the annual electricity consumption of the currently 5 570 MWh needed at Spier, using a concentrating solar power (CSP) system, was investigated. Due to rising utility-provided electricity prices, and the expected initial higher cost of the generated power, it is assumed that implemented efficiency measures would lead to a reduction in demand of 50% by 2017. However, sufficient suitable land was identified to allow electricity production exceeding today’s demand. The outcome of this study is the recommendation of a linear Fresnel collector field without additional heat storage and a saturated steam Rankine cycle power block with evaporative wet cooling. This decision was based on the system’s minimal impact on the sensitive environment in combination with the highest potential for local development. A simulation model was written to evaluate the plant performance, dimension and cost. The analysis was based on a literature review of prototype system behaviour and system simulations. The direct normal irradiation (DNI) data that was used is based on calibrated satellite data. The result of the study is a levelised cost of electricity (LCOE) of R2.741 per kWh, which is cost competitive to the power provided by diesel generators, but more expensive than current and predicted near-future utility rates. The system contains a 1.8 ha aperture area and a 2.0 MWe power block. Operating the plant as a research facility would provide significant potential for LCOE reduction with R2.01 per kWh or less (favourable funding conditions would allow for LCOE of R1.49 per kWh) appearing feasible, which results in cost competitiveness in comparison a photovoltaic (PV) solution. Depending on tariff development, Eskom rates are predicted to reach a similar level between 2017, the time of commissioning, and the year 2025. The downside is that the plant would not solely serve the purpose of electricity offsetting for Spier, which may result in a reduced amount of electricity that may be generated. Further studies are proposed to refine the full potential of cost reduction by local development and manufacturing as well as external funding. This includes identification of suitable technology vendors for plant construction. An EIA is required to be triggered at an early stage to compensate for its long preparation. / AFRIKAANSE OPSOMMING: Die Spier wynlandgoed in die Wes-Kaap Provinsie van Suid-Afrika is tans in ‘n oorgangsfase tot besigheids-praktyke gebaseer op volhoubare ontwikkeling. Afgesien van die sosiale en omgewingsaspekte het die groep hom ook ten doel gestel om koolstof neutraal te wees teen 2017. Ten einde hierdie doel te bereik, moet die maatskappy sy algehele elektrisiteitsverbruik vervang met hernubare bronne. Hierdie studie is dus geloods om die tegniese en ekonomiese uitvoerbaarheid van 'n gekonsentreerde sonkragstasie op die landgoed te ondersoek. Hierdie ondersoek is gedoen om die mees toepaslike sontermiese tegnologie en die grootte van 'n termiese sonkragstelsel te bepaal, wat aan die koolstof vereistes van die landgoed voldoen. Die potensiaal om die jaarlikse elektrisiteitsverbruik van 5 570 MWh met 'n gekonsentreerde elektriese sonkragstelsel te vervang, is ondersoek. Weens die toename in die elektrisiteitsprys en die verwagte hoërkoste van opgewekte elektrisiteit word aanvaar dat die implementering van voorgestelde doeltreffendheidsverbeteringe, sal lei tot 'n afname in die aanvraag na elektrisiteit van tot 50% teen die jaar 2017. Voldoende beskikbare grond is geïdentifiseer om genoeg elektrisiteit te produseer om die huidige vraag na elektrisiteit te oorskry. Die uitkoms van die studie is die aanbeveling van 'n lineêre Fresnel kollektorveld sonder addisionele warmte storing, asook 'n versadigde stoom Rankine sikluskragblok met ‘n nat-verdamping verkoelingstelsel. Die besluit is gebaseer op die stelsel se minimale impak op die omgewing, tesame met die hoogste potensiaal vir plaaslike ontwikkeling. 'n Simulasie is ontwikkel om die aanleg se werkverrigting, grootte en koste te evalueer. Die analise is gebaseer op 'n literatuuroorsig van 'n prototipe stelsel gedrag en stelsel-simulasies. Die direkte normale sonstralings data wat gebruik is, is gebaseer op gekalibreerde satelliet data. Die bevinding van die studie is 'n gebalanseerd koste van elektrisiteit van R2.74 per kWh, wat mededingend is met die koste van elektrisiteit wat deur diesel kragopwekkers verskaf word, maar is aansienlik duurder as die huidige en toekomstige voorspellings van Eskom-tariewe. Die stelsel bevat 'n 1.8 ha son kollektor oppervlakte en 'n 2.0 MWe krag-blok. Daarbenewens, sal die gebruik van die aanleg as 'n navorsingsfasiliteit die potensiaal hê om die gebalanseerd koste van elektrisiteit te verminder na R2.01 per kWh of minder (gunstig befondsing voorwaardes sal gebalanseerd koste van elektrisiteit van R1.49 per kWh tot gevolg hê), wat mededingend is met die koste van 'n fotovoltaïese alternatief. Daar word voorspel dat Eskom-tariewe dieselfde sal bly vanaf 2017, die jaar van inbedryfstelling van die aanleg, tot en met die jaar 2025. Die nadeel is dat die aanleg nie noodwendig uitsluitlik vir die opwek van elektrisiteit vir Spier gebruik sal word nie, en daarom kan dit lei tot 'n vermindering in die hoeveelheid elektrisiteit wat deur die aanleg opgewek word. Daar word voorgestel dat verdere studies onderneem word om die moontlikheid van koste-besparings vir die aanleg te ondersoek deur gebruik te maak van plaaslike ontwikkeling en vervaardiging, asook eksterne befondsing. Dit sluit die identifisering van geskikte tegnologie verskaffers vir die aanleg-kostruksie in. 'n Omgewingsimpakstudie, volgens die EIA regulasies, moet ook so gou as moontlik gedoen word aangesien dit n langsame proses is.

In a proposed design for a concentrated solar power tower, sand is irradiated by solar energy and transfers its energy to another fluid stream by means of a finned tube heat exchanger. To maximize heat transfer and minimize potential damage to the heat exchanger, it is desired to have a very uniform flow through the heat exchanger. However, performing full scale flow tests can be expensive, impractical, and depending upon the specific quantities of interest, unsuitable for revealing the details of what it happening inside of the flow stream. Thus, the discrete element method has been used to simulate and study particulate flows. In this project, the flow of small glass beads through a square pyramid shaped hopper and a wedge shaped hopper were studied at the lab scale. These flows were also simulated using computers running two versions of discrete element modeling software – EDEM and LIGGGHTS. The simulated results were compared against the lab scale flows and against each other. They show that, in general, the discrete element method can be used to simulate lab scale particulate flows as long as certain material properties are well known, especially the friction properties of the material. The potential for increasing the accuracy of the simulations, such as using better material property data, non-uniform particle size distributions, and non-spherical particle shapes, as well as simulating heat transfer within a granular flow are also discussed.

This study describes a simulation-based approach for informing the incorporation of Phase Change Materials (PCMs) in buildings designed to the "Passive House" standard. PCMs provide a minimally invasive method of adding thermal mass to a building, thus mitigating overheating events. Phase change transition temperature, quantity, and location of PCM were all considered while incrementally adding PCM to Passive House simulation models in multiple climate zones across the United States. Whole building energy simulations were performed using EnergyPlus from the US Department of Energy. A prototypical Passive House with a 1500 Watt electric heater and no mechanical cooling was modeled. The effectiveness of the PCM was determined by comparing the zone-hours and zone-degree-hours outside the ASHRAE defined comfort zone for all PCM cases against a control simulation without PCM. Results show that adding PCM to Passive Houses can significantly increase thermal comfort so long as the house is in a dry or marine climate. The addition of PCM in moist climates will not significantly increase occupant comfort because the majority of discomfort in these climates arises due to latent load. For dry or marine climates, PCM has the most significant impact in climates with lower cooling degree-days, reducing by 93% the number of zone-hours outside of thermal comfort and by 98% the number of zone-degree-hours uncomfortable in Portland, Oregon. However, the application of PCM is not as well suited for very hot climates because the PCM becomes overcharged. Only single digit reductions in discomfort were realized when modeling PCM in a Passive House in Phoenix, Arizona. It was found that regardless of the climate PCM should be placed in the top floor, focusing on zones with large southern glazing areas. Also, selecting PCM with a melt temperature of 25°C resulted in the most significant increases in thermal comfort for the majority of climates studied.