Dissertations / Theses on the topic 'Solar cooker'

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 63-64).
One reason that solar cookers have not gained widespread acceptance is because their use has proved inconvenient and impractical. Users are restricted to cooking when, and where, the sun is shining. Furthermore, the cooking temperature can not readily be raised or lowered as desired. In contrast, the Wilson solar cooker is designed to permit use under conditions characterized by low or no insulation. Furthermore, the design would facilitate users adjusting temperatures. These temperatures would reach levels as high as 258° C. In order to validate the concept, construction of one prototype was initiated. Lithium nitrate, the heat-storage material, was shown to meet the stated requirements of storing heat at a constant temperature of 258° C for up to six hours. Furthermore, this heat-storage material stored heat at temperatures above the boiling point of water, for up to 25 hours. Thus, it is expected that a meal for six people can be prepared up to six hours after charging of the thermal battery.
by P. Femi Akinwale.
S.M.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 22).
Solar cookers are aimed at reducing pollution and desertification in the developing world. However, they are often disregarded as they do not give users the ability to cook after daylight hours. The Wilson solar cooker is a solar cooker designed to address this problem by converting solar energy and storing that energy as heat in the form of molten salt (lithium nitrate). This thesis involved research, modeling, and experimentation for the solar collection system of the cooker. This thesis looked at prior research on glazing, Fresnel lenses, and absorber surface treatments to identify and evaluate elements for use in the collection system. Borosilicate glass, with a thermal conductivity of 1.005 W/mK and a solar transmittance of 0.91, and flat black paint, with absorptivity 0.96 and emissivity 0.88 were identified as potential elements for use in first trials. Experimentation was performed on copper and aluminum samples with various surface treatments powered by various Fresnel lenses to evaluate the relative efficiency of these treatments. A novel treatment method, machining a conical hole into the sample, was found to improve efficiency on untreated samples, but inferior to flat black paint. Modeling predicted that the minimum collection area for an acrylic Fresnel lens off-number 1.2 was 0.60 m² for and 0.65 m² for the proposed collector without and with glazing, respectively. A recommendation of collection area 1 m² was proposed to account for unexpected losses due to manufacturing errors, positioning errors, and environmental variation. This thesis also analyzed a proposal for a novel solar collector, a polished aluminum cone. Modeling and efficiency testing showed the cone to be inadequate for the radiation collection needed for the solar cooker.
by Brian Foley.
S.B.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
Extensive research and development activities have been conducted to explore opportunities for sustainable and viable methods of producing potable water using solar energy. This project included a new configuration for the solar cooker with indirect heating, which also operates as a desalination unit. The objective was to develop a new cooking pan which could be coupled with a three-stage desalination tower. Thus, the pan could be used for cooking or as the storage tank of the desalination tower. This new pan was installed in a solar cooker with indirect heating and the complete system was tested under field conditions. The sealing was improved, and the system produced more than 5.7L, with electrical conductivity lower than 10ÂS/cm, COP, 1.77 and GOR, 0,35, values consistent with the literature and above the values obtained with the original pan.
Extensivas atividades de pesquisa e desenvolvimento vÃm sendo conduzidas para explorar oportunidades de mÃtodos sustentÃveis e viÃveis de produÃÃo de Ãgua potÃvel utilizando energia solar. Este projeto abrange uma nova configuraÃÃo para o fogÃo solar com aquecimento indireto operar tambÃm como dessalinizador. O objetivo foi desenvolver uma nova panela que pode ser acoplada com uma torre de trÃs estÃgios de dessalinizaÃÃo. Assim, a panela pode ser utilizada tanto para cozinhar ou como o tanque de armazenamento da torre de dessalinizaÃÃo. Esta nova panela foi instalada em um fogÃo solar com aquecimento indireto e todo o sistema foi testado em condiÃÃes de campo. O acoplamento foi otimizado, aumentando a produÃÃo total em relaÃÃo ao projeto anterior. O sistema produziu mais de 5,7L de Ãgua dessalinizada, com condutividade elÃtrica mÃdia abaixo de 10ÂS/cm, COP, 1,77 e GOR 0,35, valores compatÃveis com a literatura e acima dos valores obtidos com a panela original.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior
This work presents two new prototypes of a circular desalinator operation in a solar cooker for indirect heating. The first prototype, called Type A, produces desalinated water from brackish water deposited in the pan solar cooker. In the second prototype, the Type B, the brackish water pan is used only as a means of transfering heat to the first tray tower desalination. These prototypes were fabricated and tested in LESGN (Solar Energy Laboratory and Natural Gas). Its structure consists of stainless steel plates, trays with circular and inclined downwards (with circular trays to facilitate the flow of condensed water) and "pipes" (that harvest desalinated water and take out the stages and side rails, harvesting the water that condenses the side walls). The desalting tower was formed by a set of trays to facilitate the handling and operation. The experiments were conducted between 7.00am and 5.00pm and the maximum number of stages was three. Experiments with 2 and 3 stages confirmed the heat recovery process, in other words, the repeated use of the heat stored in the desalinated water in a lower stage by stage above. The experimental results showed that the maximum production were daily for the Type A, 4.72 L with 3 stages, and the desalinator Type B 3.50 L also with 3 stages. It was found that the efficiency of desalination type A was greater than that of Type B, which explains why Type B has a further resistance to heat transfer. On the other hand, Type B prototype allows continued operation of the desalination tower, not requiring the dismantling after each emptying process of the water in the pan
Este trabalho apresenta dois novos protÃtipos de um dessalinizador circular para operaÃÃo em um fogÃo solar de aquecimento indireto. O primeiro protÃtipo, denominado Tipo A, produz Ãgua dessalinizada a partir da Ãgua salobra depositada na panela do fogÃo solar. No segundo protÃtipo, o Tipo B, a Ãgua salobra da panela à usada apenas como meio de transferÃncia de calor para a primeira bandeja da torre de dessalinizaÃÃo. Estes protÃtipos foram fabricados e testados no LESGN (LaboratÃrio de Energia Solar e GÃs Natural). Sua estrutura à formada por chapas de aÃo inoxidÃvel com bandejas circulares e inclinadas para baixo, com bandejas circulares para facilitar o escoamento da Ãgua condensada, âcachimbosâ, que colhem a Ãgua dessalinizada e levam para fora dos estÃgios e calhas laterais, que colhem a Ãgua que condensa pelas paredes laterais. A torre de dessalinizaÃÃo foi formada por um conjunto de bandejas para facilitar o manuseio e operaÃÃo. Os experimentos foram realizados entre 7 e 17 hs e o nÃmero mÃximo de estÃgios foi trÃs. Os experimentos com 2 e 3 estÃgios confirmaram o processo de recuperaÃÃo de calor, ou seja, a utilizaÃÃo repetida do calor armazenado na Ãgua dessalinizada em um estÃgio inferior pelo estÃgio superior. Os resultados experimentais mostraram que as mÃximas produÃÃes diÃrias foram, para o Tipo A, de 4,72 L com 3 estÃgios, e para o dessalinizador Tipo B, 3,50 L com 3 estÃgios. Verificou-se que a eficiÃncia do dessalinizador Tipo A era superior ao do Tipo B, o que se explica por o Tipo B ter uma resistÃncia a transferÃncia de calor a mais. Por outro lado, o protÃtipo Tipo B permite uma operaÃÃo continuada da torre de dessalinizaÃÃo, nÃo sendo necessÃrio a sua desmontagem apÃs cada esvaziamento da Ãgua na panela.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 22).
This paper details the analysis carried out in Solidworks to determine the best material and configuration of a thermal-storage solar cooker module.The thermal-storage solar cooker utilizes the high-latent-heat lithium nitrate releases when transitioning from liquid to solid state.However,before this process can transpire the salt has to be completely melted and the energy needed for the melting process is provided by the sun.The purpose of the module is to conduct the solar power from the heat source to the salt.In addition after the melting process,it conducts the latent energy released by the salt to the hot plate used for cooking.
by Hazel C. Zengeni.
S.B.

Sustainable energy solutions are necessary in developing nations as current food preparation practices are becoming harmful to the environment, economic development and the overall health of the population. The purpose of this study was to create a Scheffler reflector-based system prototype, experimentally analyze the system and to predict its behavior when subjected to the solar conditions of Rajasthan, India. Former designs from India, the University of Iowa and several other institutions were consulted during the formulation of the prototype design. While consulting a specific set of design constraints, pertinent to developing counties, a Scheffler reflector and tracking stand were fabricated. Solutions for a thermal storage unit were investigated for eventual integration with the prototype. Solar flux data for Iowa and India was used to predict the amount of energy transmitted by the reflector. Experiments were designed and completed to observe the temperatures experienced at the focal point of the reflector and estimate the energy stored by a steel mass. A series of sun angles, monthly solar flux data and experimental data were used to predict the performance of the storage unit, over a three day span, in Rajasthan. Aspects of the system were then modified to investigate their effects on the temperature of the storage unit.

A promising and novel solar concentrator design has been thoroughly investigated and optimised. A prototype concentrator based on this novel geometry was validated using ray tracing techniques. This ray tracing demonstrated the comparative performance of this novel concentrator in regards to equivalent parabolic dishes. The effect of mirror surface normal errors on performance was established using Monte-Carlo based ray tracing code, which agreed well with the optical performance of this prototype which was determined experimentally. A need for low-cost solar cookers to replace bio-mass worldwide was identified, and the concentrator design was then developed as a low-cost solar oven. Despite existing in some number, no current design is able to achieve high performance at low-cost. An industrial partner, Dytecna, was initially involved in the process of this development of the system as a solar cooker. In support of a field trial for the solar cooker developed with Dytecna, a detailed thermal model of the oven was developed. A low-cost lightmeter was constructed and calibrated in order to measure the direct normal irradiance during the field trial in Italy. Laboratory work provided baseline results for the heating of various thermal masses in the oven. The Italian field trials provided a wealth of feedback into the design of the system and many valuable results. The solar cooker was able to bring 0.75L of water to the boil in 33 minutes with an average heat throughput of 203W. Important benchmark results and practical experience of several competing receiver materials was obtained; further lab testing provided more accurate measurements of the receivers' performances. The experiences of the Italian field trial were fed back into the design of a subsequent prototype, intended for a much larger field trial in Tanzania. Improvements in the hotplate, receiver material, and the oven were all incorporated into the design. Additionally, the structure of the solar cooker was redesigned to incorporate a low-cost wooden construction. Supporting work was conducted for the month long trial in which 8 solar cookers would be distributed to families in Tanzania. The field trial in Tanzania provided a wealth of user feedback into the design. At the same time the new solar cooker exceeded previously established performances in Italy. The new design was able to provide an average of 246W of heat to 1kg of water, which was brought to boiling point in 25 minutes. This represents a heating efficiency of 66% compared to the incident solar flux on the hotplate. In response to findings during the Tanzanian trials, further laboratory work was conducted into establishing the reflectivities of low-cost candidate mirror materials. Throughout all phases of the project the design of the solar cooker was refined and improved with the goal of a solar cooker design that could reach price-point, performance, and usability standards which would ensure market success.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 45).
There is a large need in third-world tropical areas for a method of cooking in which users need minimal resources and traversing to heat food at night. A solution to this problem is to create a stored-heat solar cooker that may be left during the day and acquired at night to cook meals. Previously, a prototype had been built without much success in the timing of the device. This thesis aims to solve this problem by designing, building, and testing a mechanical timer. Several design choices were narrowed to the fabrication and testing of a hydraulic design similar to a gas spring. After this particular iteration of the prototype, proof of concept seems feasible. The next iterations of this timer should incorporate several design changes regarding the o-ring sealing and other various details for proper assembly and decreased cost.
by Julia C. Hsu.
S.B.

L'utilizzo di energia solare termica deve essere sostenuto per ridurre il consumo di fonti fossili climalteranti. Nel presente studio si sono progettati e realizzati due sistemi solari a concentrazione: un collettore parabolico assiale (PTC) ed un forno solare a scatola. Il PTC ha un angolo di bordo di 90° ed un rapporto di concentrazione di 19,89. Sul concentratore, realizzato in sandwich composito, sono state applicate pellicole in alluminio ad elevata riflettanza. Il ricevitore è un tubo di acciaio rivestito da una vernice selettiva. Il sistema di inseguimento è governato da un algoritmo solare. I test sperimentali sono stati condotti con acqua ad una temperatura massima di 85 °C. Il PTC è stato caratterizzato ottenendo curve di efficienza termica, modificatore dell'angolo di incidenza e costante di tempo. I risultati mostrano che l'equazione dell'efficienza termica è confrontabile con quella di collettori simili. I dati sperimentali sono stati utilizzati per validare un ambiente di simulazione della resa annuale di PTC. Si è determinata la convenienza nell'adozione di nanofluidi a base di metalli rispetto al fluido di base (acqua). Sono state analizzate 5 temperature del fluido in ingresso e 3 portate in massa. I risultati mostrano che solo le nanoparticelle di Au, TiO2, ZnO e Al2O3 alle più basse concentrazioni presentano ridotti miglioramenti. Il forno solare a scatola ha un rapporto di concentrazione di 11,57, ed è costituito da una camera di cottura, un coperchio superiore vetrato e una doppia fila di specchi riflettenti. Il prototipo consente un allineamento solare manuale sia azimutale che zenitale. La temperatura massima del forno è stata determinata attraverso prove a vuoto. Sono state inoltre svolte prove a carico inserendo nel forno una o due pentole di alluminio, verniciate o meno in nero, riempite con acqua o olio di arachidi. In quest’ultimo caso, si è giunti a temperature superiori a 200 °C e a risultati confrontabili con quelli in letteratura.
Use of solar thermal energy has to be sustained to reduce consumption of climate-changing fossil fuels. Thus, in this study two concentrating solar prototypes were designed and manufactured: a parabolic trough collector (PTC) and a solar box cooker. The PTC has a 90° rim angle and a concentration ratio of 19.89. The concentrator is a sandwich composite structure with high-reflectance aluminum foils applied on it. The receiver is a steel pipe painted with a selective coating. The tracking system is based on a solar-position computer program. Experimental tests were carried out with water and temperatures up to 85 °C. Thermal efficiency, incident angle modifier, and time constant curves were found. Results show that the thermal efficiency equation is comparable with that of other PTCs in literature. Experimental data were utilized to validate a simulation environment able to determine the yearly yield of PTCs. The simulation was carried out to evaluate the convenience in adopting metal-based nanofluids respect to the base fluid (water). Five inlet fluid temperatures and three mass flow rates were analyzed. Results show that only Au, TiO2, ZnO, and Al2O3 nanoparticles, at the lowest concentrations, present reduced improvements respect to water. The solar box cooker is a high concentration ratio prototype (11.57). The cooker has a cooking chamber with a glass cover on the top and is composed by two rows of booster mirrors. The prototype allows both an azimuth and a zenith manual orientation. Tests without load were carried out to evaluate the maximum cooker temperature. Tests with load, conduced using aluminum vessels containing a certain amount of water, were accomplished both with non-painted vessels and black-coated ones, and with one or two vessels. Additional tests were carried out with peanut oil. Using this fluid, temperatures higher than the water ones were achieved (> 200 °C) and results exhibited values comparable to those in literature.

Orientador: Prof. Dr. João Batista de Aguiar
Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Mecânica, 2016.
No Haiti, bem como em regiões do norte e nordeste do Brasil, os recursos florestais são utilizados como lenha ou transformado em carvão vegetal para fins de cocção, principalmente pela população de baixa renda. Através desta ideia, este trabalho é desenvolvido apresentando um conceito de um fogão solar acessível de tipo caixa, utilizando materiais de baixo custo e técnicas simples de construção. A fim de desenvolver uma primeira análise de ordem do fogão, o problema de transferência de calor transiente é formulado e o sistema de equações diferenciais são escritos e resolvidos. Diferentes cenários e parâmetros são considerados para compreender a importância do problema. Foram utilizadas dimensões, formas e materiais alternativos ao apresentado na literatura. Um modelo físico do fogão solar foi construído no local em questão "Haiti" e medições de temperaturas realizadas e comparadas com as previsões numéricas. A partir da analise dos resultados, chegou-se às conclusões. Outras adições à solução também foram incluídas, a resposta obtida foi demostrada, de forma a apresentar se os resultados são aceitáveis.
In Haiti as well as in northern and northeastern of Brazil, forest resources are used as wood or transformed into charcoal for cooking, mostly by poor people. Through this idea, this work presents a concept of an affordable box type solar oven, using cheap materials and easy construction techniques. In order to develop a first order analysis of the oven, the transient heat transfer problem is formulated, the system of differential equations written and solved. Different scenarios and parameters are used to understand the importance to the problem. Variations range from dimensions, forms and materials. A physical model of the oven is constructed in locus "Haiti" and temperature measurements performed and compared to numerical predictions. The results are analyzed and conclusions drawn. Other additions to the solution are included, obtained answer is presented in order to show whether it is acceptable.

The high energy density and stable temperature fields of latent heat thermal storage devices (LHTSD) make them promising in a range of applications, including solar energy storage, solar cooking, home heating and cooling, and thermal buffering. The chief engineering challenge in building an effective LHTSD is to find a way to complement the storage capabilities provided by the low-conductivity phase-change material with a suitable enhanced heat transfer mechanism. The principal aim of this project is to develop a tool to improve the design of a small-scale LHTSD, such as one that might be used in solar cooking for a family. An effective small-scale storage device would need to absorb solar energy quickly, release the energy at a high temperature, be affordable, and be manageable within a small household. An LHTSD using solar salts fulfills the latter two requirements: solar salts, a near-eutectic mixture of NaNO3 and KNO3 (60/40% by mass) commonly used in thermal storage applications, are inexpensive and widely available, and the use of latent heat storage means a relatively small chamber can hold enough energy to cook a family meal. The challenge, however, is to design a device that absorbs and releases energy from the solar salts, which have a very low thermal conductivity. The most practical tool to improve the spread of heat through the salts is a finned metal core within the LHTSD. This project uses numerical simulation to determine the most effective design of this finned core. A Cartesian grid solver is developed that is capable of simulating the convection-dominated melting processes within the storage device. The phase boundary is tracked using the enthalpy method, and conjugate heat transfer is calculated with a strongly coupled implicit scheme. A number of techniques are then used to with this solver in order to better understand the factors that affect the performance of a LHTSD and to improve the design of such devices. The thesis is organized as an introductory section followed by three case studies. In the first section, the project is introduced, and the governing equations and core numerical methods are described. In addition, a set of test simulations demonstrate that results using the developed numerical scheme match those of a range of experimental and numerical benchmarks. Each of the case studies aims to adapt the numerical scheme to a more specific problem concerning LHTSDs. In the first, the performance of four fin designs are compared over long-term (48 hour) simulations; the aim is to test the potential performance of the four LHTSDs given realistic solar conditions in New Delhi, India. In the second case study, a set of physical experiments are performed in an empty and a finned LHTSD, and matched 3-dimensional numerical simulations are used to explore the thermal, melt, and flow behavior of the solar salts with the chambers. The final study uses the computational scheme to optimize the design of the finned core of an LHTSD over a large parameter space. To optimize the best design, the key parameters are first prescreened to find which three parameters have the largest effect on the objective equation. A machine-learning optimization code using the dynamic Kriging method (DKG) is then used to build a response surface from which the optimized design can be determined. These three cases demonstrate the potential of the numerical scheme to explore the performance of finned LHTSD designs in a range of ways: the scheme can be used to predict behavior of devices in realistic conditions, to explore the behavior of solar salts during the melting and solidification process, and to determine an optimal design within a large parameter space. In doing so, they show the potential of this tool to help improve the performance and practicality of small-scale LHTSDs.

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Universidade Federal do Rio Grande do Norte
Given the growing environmental crisis caused by degradation, mainly due to the use of polluting energy sources, increasing the growing use of renewable energies worldwide, with emphasis on solar energy, an abundant supply and available to everyone, which can be harnessed in several ways: electricity generation; dehydration of food; heating, disinfection and distillation and cooking. The latter has as its primary feature the viability of clean, renewable energy for society, combating ecological damage caused by large-scale use of firewood for cooking foods, use in tropical countries with high solar radiation, and has funding NGOs throughout the world with the goal of achieving low-income population. The proposed project consists of a solar cooker for concentration, working from the reflection of sunlight by a hub that they converge to a focal point at the bottom of the pot, getting lots of heat. The solar cooker under study consists of two elliptical reflecting parabolas made from the recycling of scrap TV antenna, having 0.29 m? of surface area for each antenna, which were covered by multiple mirrors of 2 mm thick and mounted on a metal structure, with correction for the mobility of the apparent movement of the sun. This structure was built with the recycling of scrap metal, possessing a relatively low cost compared with other solar cookers, around US$ 50.00. This cost becomes negligible, since that will involve a great benefit to not have fuel costs for each meal, unlike the use of gas or firewood for cooking food. The tests show that the cooker has reached the maximum temperature of 740 ? C, for boiling water in an average time of 28 minutes, cooking various types of foods such as potatoes, rice and pasta in an average time of 45 minutes and still going as a solar oven, making pizza baking and meat. These cooking times do not differ much from the cooking times on a gas stove, it becomes the solar cooker as a good consumer acceptance, and furthermore not to deliver the same gases that can poison the food as with the wood stove. Proves the viability of using the stove to cook or bake in two daily meals for a family, still presenting a position to improve his performance with the addition of new materials, equipment and techniques
Diante da crescente crise ambiental provocada pela degrada??o, principalmente devido ao uso de fontes energ?ticas poluentes, cada vez mais, vem crescendo o uso de energias renov?veis em todo o mundo, tendo destaque para a energia solar, uma fonte abundante e dispon?vel a todos, que pode ser aproveitada de diversas maneiras como: gera??o de eletricidade; desidrata??o de alimentos; aquecimento, desinfec??o e destila??o de ?gua e coc??o. Este ?ltimo tem como aspecto primordial a viabiliza??o de energia limpa e renov?vel para a sociedade, combatendo os danos ecol?gicos causados pela utiliza??o em larga escala de lenha para o cozimento de alimentos, tendo utiliza??o em pa?ses tropicais com altos ?ndices de radia??o solar, possuindo financiamento de ONGS por todo o mundo com objetivo de atingir a popula??o de baixa renda. O projeto proposto consta de um fog?o solar ? concentra??o, funcionando a partir da reflex?o dos raios solares por um concentrador que converge os mesmos para um ponto focal no fundo da panela, recebendo grande quantidade de calor. O fog?o solar em estudo ? composto por duas par?bolas refletoras de forma el?ptica feitas a partir do reaproveitamento de sucatas de antena de TV, possuindo 0,29 m? de ?rea superficial para cada antena, que foram cobertas por m?ltiplos espelhos de 2 mm de espessura e montadas em uma estrutura met?lica com mobilidade para a corre??o do movimento aparente do sol. Esta estrutura foi constru?da com o reaproveitamento de sucata, possuindo um custo relativamente baixo, quando comparado com outros fog?es solares, em torno R$ 100,00. Este custo torna-se insignificante, uma vez que promover? um grande benef?cio em n?o possuir gastos com combust?vel para cada refei??o, diferente do uso do g?s ou de lenha para cozinhar alimentos. Os ensaios mostram que o fog?o chegou ? temperatura m?xima de 740?C, realizando a ebuli??o de ?gua em um tempo m?dio de 28 minutos, cozinhando diversos tipos de alimentos, como batata, arroz e macarr?o em um tempo m?dio de 45 minutos e ainda funcionando como forno solar, realizando o assamento de pizza e carnes. Esses tempos de cozimento n?o diferem muito dos tempos de cozimento em um fog?o ? g?s, fato que obt?m ao fog?o solar uma boa receptividade aos consumidores, al?m do mesmo n?o emitir gases que podem intoxicar os alimentos como no caso do fog?o a lenha. Comprova-se a viabilidade da utiliza??o do fog?o para cozinhar ou assar em duas refei??es di?rias para uma fam?lia, apresentando ainda condi??es de melhorar sua performance com adi??o de novos materiais, equipamentos e t?cnicas

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Presents a composite formed by orthophthalic resin and fiber loading of carnauba straw. The fibers were first dried in direct sun exposure and subsequently ground into fodder for the reduction in size. Various formulations of the composite were preliminarily tested by choosing the one presenting the best processability in applying the mold. The composite produced is used for the manufacture of a parabolic surface subsequently coated with mirror segments, flexible plastic, for reflecting the solar rays incident on it. The reflective parable represents the main element of the solar cooker that works with the concentration of sunlight and has dimensions of 1.14 m in diameter and area of 1.0 m?. Manufacturing processes and assembly of solar cooker concentration produced are presented. The results of tests for cooking and baking various foods, including rice, pasta, beans, cake, cassava, shrimp, beef, breaded demonstrating the competitiveness of solar cooker studied with other stoves already manufactured and tested in Brazil are presented and in the world. It was also demonstrated the feasibility of the proposed composite for Prototypes manufacture of solar and other structures that do not require great efforts resistance
Apresenta-se um comp?sito formado por resina ortoft?lica e carga de fibra da palha da carna?ba. As fibras foram inicialmente secadas em exposi??o direta ao sol e posteriormente trituradas em forrageira para a diminui??o do seu tamanho. V?rias formula??es do comp?sito foram preliminarmente ensaiados, escolhendo-se a que apresentava a melhor processabilidade na aplica??o ao molde. O comp?sito produzido ? utilizado para a fabrica??o de uma superf?cie parab?lica, posteriormente revestida com segmentos de espelho pl?stico, flex?vel, para a reflex?o dos raios solares nela incidentes. A par?bola refletora representa o principal elemento do fog?o solar que trabalha com a concentra??o dos raios solares e possui dimens?es de 1,14m de di?metro e ?rea de 1,0m?. S?o apresentados os processos de fabrica??o e montagem do fog?o solar ? concentra??o produzido. S?o apresentados os resultados dos ensaios para o cozimento e assamento de v?rios alimentos, dentre eles arroz, macarr?o, feij?o, bolo, macaxeira, camar?o, carne, empanados que demonstraram a competitividade do fog?o solar estudado com outros fog?es j? fabricados e ensaiados no Brasil e no mundo. Tamb?m foi comprovada a viabilidade do comp?sito proposto para a fabrica??o de prot?tipos solares e outras estruturas que n?o requerem resist?ncia a grandes esfor?os

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The proposed design provides a solar furnace alternative, box-like, low-cost operation to be used in cooking, comprising three scrap tires to make the recycling thereof. The tires were coupled to each other, forming an enclosure, which stood on its bottom covered by a parable multiple mirrors made from a urupema (sieve indigenous) and the inner sides of the oven aluminum sheet painted black, obtained from beer cans, thus being made to obtain the increase in the concentration of solar radiation incident on the inside of the prototype studied. Two tires were attached, leaving an air layer between them, with the function of thermal insulation. The third tire aimed to support the other two and thermally insulate the bottom of the oven. Externally was placed a metal frame with flat mirrors to reflect the incident rays into the oven, having a mobility to correct the apparent motion of the sun. Its primary feature is the viability of clean, renewable energy to society by tackling the ecological damage caused by the large-scale use of wood for cooking food. The tests show that the furnace reached the maximum temperature of 123.8 ?C and baking various foods such as pizza, bun, and other lasagne in an average time 50 minutes. Proves the feasibility of using the oven. Presenting still able to improve their performance with the addition of new materials, equipment and techniques
O projeto proposto apresenta um forno solar alternativo, tipo caixa, de baixo custo para ser utilizado na opera??o de coc??o, composto por tr?s sucatas de pneus, para fazer a reciclagem dos mesmos. Os pneus foram acoplados entre se, formando um recinto, onde se colocou em sua parte inferior uma par?bola coberta por m?ltiplos espelhos confeccionada a partir de uma urupema (peneira ind?gena) e nas laterais internas do forno chapas de alum?nio pintadas da cor preta, obtidas de latas de cerveja, sendo feito assim para a obten??o do aumento na concentra??o da radia??o solar incidente no interior do prot?tipo estudado. Dois pneus foram unidos, ficando uma camada de ar entre eles, com a fun??o de isolante t?rmico. O terceiro pneu teve a finalidade de suporte para os outros dois e isolar termicamente o fundo do forno. Externamente foi colocada uma estrutura met?lica com espelhos planos para refletir os raios incidentes para o interior do forno, possuindo uma mobilidade para a corre??o do movimento aparente do sol. O seu aspecto primordial ? a viabiliza??o de energia limpa e renov?vel para a sociedade, combatendo os danos ecol?gicos causados pela utiliza??o em larga escala de lenha para a coc??o de alimentos. Os ensaios mostram que o forno chegou ? temperatura m?xima de 123,8?C, assando v?rios alimentos como pizza, bolo, lasanha entre outros em um tempo m?dio de 50 minutos. Comprova-se a viabilidade da utiliza??o do forno. Apresentando ainda condi??es de melhorar seu desempenho com adi??o de novos materiais, equipamentos e t?cnicas

This thesis introduces an analysis and dimensioning of a solar powered solution for enabling clean and sustainable cooking in developing areas. Access to clean cooking is a great  challenge  hindering human development, with significant health, environmental, and economic implications. The proposed solution is analysed and modelled in this work. Recommendations are given on the development of the project, reviewing the critical factors for its success. The solution is a novel approach for providing power for cooking through solar energy. Targeted market segment is institutional cooking, where current cooking fuels are commonly based on firewood and charcoal. The system integrates a solar trough collector array, an oil heat storage,     a heating unit for the cooking recipient, and two thermosiphons for transporting the heat between each component. The technology is under development, requiring an accurate analysis and further work in the design. The work presented analyses the solution and its implementation in a specific case study. A modelling software was built as a tool for dimensioning the technology and observing its behaviour. Moreover, specific values were obtained on the dimensions for the case study. A structured critic of the system through a deep review allowed for observations on risks, future work, and additional recommendations. Simulations for the case study enabled the first values on the dimensions of the system. Flexibility of the model was provided to repeat this exercise for future case studies. The analysis unexpected critical factors for the solution such as user behaviour and reviewed expected ones such as the insulation or the size of the heat storage. There are still many challenges to overcome for the success of the analyzed project. This thesis gives a basis for future work and strong guidance for the development of the solution.

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It is presented a solar cooker made with a parabolic reflector composed by a composite material. For this purpose, it was utilized a cast concrete with a parabolic profile obtained by means of modeling. It will be demonstrated the manufacturing process and settings, as well as tests results, in order to determine the contact temperature and cooking time of some foods. This solar cooker presents the following main characteristics: the concentration method, low cost and easy manufacturing process. It was performed by employing recycled materials such as cement, plaster, crushed polystyrene and wheels. The captation area measures 1 square meter and its parabole was covered with a mirrors measuring 25 cm2. A temperature higher than 650?C was obtained. Furthermore, it has been demonstrated that the cooking viability for several type of foods such as beans, potatoes, rice, yams and pasta can be used in two meals for a family of four. In addition, the advantages of this cooker were analysed in comparison with others described in literature as well as those operating on gas. Especially in Northeast of Brazil, where there is a potential for solar energy, this prototype is an important tool, because it avoids not only desertification, but also pollutants from burning firewoods which cause ecological imbalance
Apresenta-se um fog?o solar a concentra??o com par?bola refletora constru?da com um material comp?sito. Foi utilizado um molde de concreto com perfil parab?lico obtido atrav?s da modelagem. Ser?o apresentados os processos de fabrica??o e montagem bem como os resultados de testes para determinar a temperatura de contacto e os tempos de cozedura de certos tipos de alimentos. O fog?o solar a concentra??o tem como principal caracter?stica seu custo baixo, sendo produzidos a partir de uma composi??o de materiais reutiliz?veis, como cimento, gesso e EPS triturado e pneus. Apresenta ?rea de capta??o de 1,0 metro quadrado e sua par?bola foi coberto com segmentos de espelhos de 25 cm?. As principais carracter?sticas do fog?o solar ? concentra??o propostas s?o seus f?ceis processos de fabrica??o, montagem e seu baixo custo. Obteve-se temperatura de foco superioor a 650?C. Demonstrou-se a viabilidade de coc??o desse fog?o solar para v?rios tipo de alimentos como feij?o, batata, arroz, inhame e macarr?o e podendo ser usado em duas refei??es para uma fam?lia de quatro pessoas. A competitividade do fog?o solar estudado com outros apontados pela literatura solar para coc??o de alimentos e at? mesmo com o fog?o a g?s para excelentes condi??es solarim?tricas. Este prot?tipo pode representar uma importante contribui??o para o uso de fog?es solares, especialmente no Nordeste, para o combate ? desertifica??o, e emiss?o de poluentes pelo uso massivo de lenha, que causa desequil?brio ecol?gico nessa regi?o

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An alternative box-type solar cooker built starting from the scrap of a tire and a scrap of old office chair is presented, which principles functions are the effect greenhouse and the concentration. The tire served as structure for making of is the baking enclosure where the absorber (roasting pan 20x30cm) of the solar is located, being re-covered for a glass blade for the generation of the greenhouse effect isolated lateral and having deep its and for a composite the plaster base and EPS. Segments of plain mirrors had been placed in the laterals of the oven/cook for the concentration of the radiation and a reflecting parable was introduced in the baking enclosure for the exploitation of the incident reflected radiation inside of the oven/cook. The oven/cook is mobile to allow one better aiming of exactly in relation to the apparent movement of the sun. The thermal economic and of materials viabilities of the stove/cook in study will be demonstrate. The average internal temperature of the absorber was around 152,3?C and the internal temperature around 110?C. Will demonstrate that toits low cost and good thermal performance, represents basic characteristics for the viability of large use of such archetype, mainly for cooking the decreases and averages temperatures. One will reveal that the archetype in study is competitive with the box-type solar cooker conceived in the whole world
Apresenta-se um forno/fog?o solar alternativo de baixo custo para ser utilizado nas opera??es de assar e cozinhar, que foi constru?do a partir de uma sucata de pneu. O pneu foi cortado na parte superior para aumentar a ?rea de capta??o da radia??o solar incidente. Utilizou- se comp?sito a base de gesso, EPS (poliestireno expandido) triturado e ?gua para revestir internamente a carca?a do pneu e o fundo da mesma para minimizar as perdas t?rmicas. Ser?o estudadas tr?s configura??es, onde ser?o utilizados dois tipos de par?bolas refletoras. Uma confeccionada a partir de uma tampa de prote??o de uma sucata de ventilador e outra a partir de uma urupema, peneira usada para comidas de milho. Acima da cobertura de vidro foi colocada uma estrutura com espelhos planos para refletir os raios incidentes para o interior do forno/fog?o solar. A estrutura de sustenta??o do forno/fog?o solar, com os movimentos necess?rios ao acompanhamento do movimento aparente do sol foi confeccionada utilizando uma sucata de cadeira girat?ria. O forno/fog?o solar proposto apresenta maior viabilidade para a opera??o de assar. Obteve-se uma temperatura m?xima no absorvedor em torno de 160? e interna em torno de 120?C. Demonstrar-se-? as viabilidades t?rmica, econ?mica e de materiais do forno/fog?o solar proposto

Detta projekt är ett samarbete mellan Hampus Nilsson och Joto Solutions, projektet är ett examensarbete för Högskoleingenjörsexamen i innovationsteknik och design, MSGC12 vid fakulteten för hälsa, natur- och teknikvetenskap på Karlstads universitet. Studenten ska tillsammans med Joto Solutions utveckla kokenheten på deras solkokare. Projektet motsvarar 22.5 hp och utförs under vårterminen 2017. Handledare i projektet är Lennart Wihk, universitetsadjunkt, och examinator är Leo De Vin, professor. Joto Solutions AB startades våren 2015 i samband med två examensarbeten som initierades av Adam Fjaestad i Arvika. Under 2016/2017 avser Joto Solutions att göra en satsning på att utveckla och produktifiera solkokaren som sedan ska testas i fält. Målet med projektet att utveckla en design på solkokarens kokenhet som är väl anpassad för slutanvändaren. Frågeställningen som behandlas i rapporten är ”Hur ska solkokarens kokenhet utformas för att tillfredsställa slutanvändarens behov”. Projektet följer ett ingenjörs- och industridesignmässigt arbetssätt och grundar sig i produktutvecklingsprocessen. De faser som behandlas i detta projekt är projektplanering, förstudie, produktspecifikation, konceptgenerering, konceptval och layoutkonstruktion. Projektet resulterade i tre stycken kokenheter med varierande design som redovisas i layoutkonstruktionsfasen. Det finns utrymme för framtida vidareutveckling av de tre variationerna av kokenheten i form av konstruktionsförbättringar och säkerhetstillhörigheter.
This project is a collaboration between a student and the company Joto Solutions and is a degree work for a degree of bachelor in the field of innovation and design, MSGC12 at Karlstad University, Faculty of Health, Science and Technology. The student, together with Joto Solutions, will develop the cooking unit on their solar cooker. The project is equivalent to 22.5 ECTS credits and is being executed in the spring of 2017. Supervisor of the project is Lennart Wihk, a university lecturer, and the examiner is Leo De Vin, the professor. Joto Solutions AB was founded in the spring of 2015 in connection with two degree projects initiated by Adam Fjaestad in Arvika. In 2016/2017, Joto Solutions intends to make an effort to develop their solar cooker which will then be tested in the field. The aim of the project is to develop a design on the solar cooker's cooking unit that is well adapted to the end user needs. The question discussed in the report is "How should the solar cooker's cooking unit be designed to satisfy the end user's needs in a cultural and functional perspective." The project follows an engineering and industrial design practice and is based on the product development process. The phases covered in this project are project planning, preliminary study, product specification, concept generation, concept selection, layout design and risk analysis. The project resulted in three cooking units with varying designs that are presented in the layout design phase. There is room for further development of the three variations of cooking units in the form of design improvements and safety issues.

It is well known that the seats in a parked vehicle become very hot and uncomfortable on warm days. A new self-powered thermoelectric car seat cooler is presented to solve this problem. This study details the design and optimization of such a device. The design relates to the high level layout of the major components and their relation to each other in typical operation. Optimization is achieved through the use of the ideal thermoelectric equations to determine the best compromise between power generation and cooling performance. This design is novel in that the same thermoelectric device is utilized for both power generation and for cooling. The first step is to construct a conceptual layout of the self-powered seat cooler. Using the ideal thermoelectric equations, an analytical model of the system is developed. The model is validated against experimental data and shows good correlation. Through a non-dimensional approach, the geometric sizing of the various components is optimized. With the optimal design found, the performance is evaluated using both the ideal equations and though use of the simulation software ANSYS. The final design consists of a flat absorber plate embedded into the car seat with a thermoelectric attached to the back. A finned heat sink is used to cool the thermoelectric. The device is shown to generate enough power to provide a reasonable temperature drop in the seat.
Master of Science

Two design analysis programs that model the performance of solar heated and passively cooled homes in the climate of BURUNDI are presented. The new programs, SOLBUDI and COLBUDI, are based on the design analysis programs SOLASEC and COOLASEC which have been modified to account for skylights, solar heat gains on wall and roof surfaces, as well as nocturnal radiation effects on the roof. Additionally, Bjumbura (∼ 800 meters in altitude) weather data and the thermal properties of building materials commonly used in Burundi are incorporated into the programs. Typical weather data for cities at mid-altitudes (∼ 1500 meters) and high altitudes (>2000 meters) are also presented. Due to the great variation in altitude (700 meters - 2600 meters) and climate in Burundi, both heating and cooling are required, hence the need for both heating (SOLBUDI) and cooling (COLBUDI) design analysis programs. Skylights, east windows, and west windows are the best sources of solar gain in Burundi due to the high solar angles, which are present all seasons. Thus, solar gains through these apertures must be controllable to prevent overheating during the warm season.

Freshwater scarcity is a major obstacle of growth and prosperity for many nations in the world. Conventional centralised freshwater supply options in general are depleting and the unanticipated social and environmental costs of alternative solutions are emerging. Similar to energy, water sector may also need to explore renewable decentralised freshwater alternatives such as atmospheric moisture as discussed in this thesis. For hot and humid regions, condensed water is unwillingly discharged out of air-conditioning systems and the energy consumed for condensation to full humidity comfort level is wasted. Only a few limited small-scale experimental studies and no systematic modelling have been found in the literature on atmospheric water capture. This thesis works to fill some of this gap by developing an understanding of the fundamental factors that have and continue to challenge the development of technologies for atmospheric water capture. In this thesis, a framework is developed encompassing several modelling elements for assessment of feasibilities of moist air dehumidification technologies for atmospheric water capture. This framework integrates technical, meteorological and economic modelling elements. In the technosphere, detailed models of thermoelectric and absorption cooling are developed as potential dehumidification technologies. These models are interfaced to renewable energy input algorithms, namely solar photo-voltaic (PV) and solar-thermal. Solar energy collection technologies are also part of this framework which includes models of solar PV systems and evacuated tube collectors (ETCs). Studies of such integration of solar-assisted dehumidification and associated analysis for atmospheric water capture are limited in the literature. Fundamental solar energy input models are developed and interfaced to meteorological data to provide geographical location specific analysis. In this way the model framework is generic and applicable to any location on Earth where meteorological data is available. Finally, an economic modelling component completes the framework to provide comprehensive techno-economic assessments of different technologies for atmospheric water capture. This framework therefore provides a tool to support decision making related to feasibilities of different technologies associated with water capture from atmosphere. Along the way to developing the modelling framework, a detailed categorisation of dehumidification systems is established and a model to estimate condensation rates based on local climate data is built. The hurdle of condensation energy requirement is highlighted through simulation results. To alleviate this energy burden, an assessment of renewable solar energy input is then made. Techno-economic challenges for two different climates, Sydney and Abu Dhabi are examined and compared throughout this thesis providing comparisons for water and energy profiles. Several modelling components are developed and presented f or this purpose, requiring implementations in different modelling environments including Matlab, Trnsys, Homer and VBA. Based on the operation principles, dehumidification techniques are categorised into three categories in this thesis (Fig. 2.2). Gas separation membrane technologies were modelled but are not included in this thesis presentation because initial analysis showed they suffer from several key technical drawbacks primarily associated with the sensitivity to fluctuations in feed air temperature and humidity. Technologies in the cooling surfaces category in general use electrical or mechanical power to circulate and compress a refrigerant and cooling down conductive surfaces or coils. This process aims to decrease the temperature of moist air stream below dew point where water vapour molecules start to bond and settle forming the condensation stream. Amongst a wide range of cooling surface techniques, thermoelectric cooler (TEC) devices are attachable to cooling surfaces without using a refrigerant medium. A conceptual TEC dehumidification system is modelled in this thesis targeted at moist air streams with ambient temperature ranges (10-50) C and relative humidity ranges (10-100) %. For large-scale water production, the energy cost is calculated and found to be the major factor contributing to more than 95% of the total cost of generated water. This model is implemented for Sydney and Abu Dhabi case studies by using their annual typical meteorological weather data. This shows the generic nature of the applicability of the model and in this specific comparison confirms the influence of energy consumption over the cost of generated water in those two very different regions. However, lower local utility rates and favourable climatic conditions for dehumidification in Abu Dhabi show significant differentiation in water cost over Sydney. To confront excessive energy demands for atmospheric water capture, the idea of facilitating solar energy via PV panels is examined in this thesis. A comprehensive solar algorithm is developed and implemented to optimise solar collector positioning and for calculating solar penetration ratios for Sydney and Abu Dhabi. As far as the author is aware, this is the first time such optimal position calculation for Sydney and Abu Dhabi is done. It is found that optimal surface tilt angles for Sydney and Abu Dhabi are 32 and 22 respectively, while optimal surface azimuth angles for Sydney and Abu Dhabi are 195 and 16 respectively. This algorithm is generic in its structure allowing such calculation to be executed for any city in the world and is later used in this thesis for calculations associated with a new ETC diffuse at reflector (DFR) model. This thesis also presents a detailed economic model for prediction of utility costs with consideration for CAPEX, OPEX, subsidies and carbon taxation. It is found that investing a $338,000 on a PV array of 100 kW at current utility rates can meet 53% of energy demand of proposed dehumidification system and reduce LCOE by 6 c/kWh in Sydney. Solar PV array at current utility rates to feed proposed dehumidification system is found to be uneconomical for Abu Dhabi. Solar-thermal collectors represent an attractive option for driving refrigeration techniques. Evacuated tube collection technology has progressed significantly over the last few years and this technology is assessed in this thesis as a heat collector for absorption chillers. The role of DFR to improve the performance of ETC is highlighted and modelled. Results showed that DFR can significantly improve ETC performance by an average of 24.1% for Sydney and 22.9% for Abu Dhabi respectively. The optimisation of DFR is therefore an important factor for the enhancement of this solar energy collection technology and the algorithm developed in this thesis is generically applicable across geographical locations. The concept of solar refrigeration is reviewed and investigated for the implementation of sorption refrigeration. Sorption techniques use low-grade heat sources such as solar energy to convert thermal heat into chilling effect. This function is investigated for dehumidification of a moist air stream via cooling coils. A conceptual absorption model is developed in TRNSYS to calculate overall energy demand and water productivity. An ASHRAE algorithm is developed and implemented to cross validate the TRNSYS model. This absorption model was used in an optimisation analysis and showed water productivity improvement of 29% for Sydney and 34% for Abu Dhabi, while energy demand can be reduced by 22% for Sydney and 55% for Abu Dhabi. Unlike Sydney, the cumulative cost of generated water is declining over time in Abu Dhabi reaching $15 /kL. If this system is projected to work during the day only, solar penetration ratio will substantially increase and could meet the entire diurnal load for dehumidification in Abu Dhabi. If the capital cost of developing such system is affordable, absorption model can be further optimised to specifically match local conditions in respect to solar radiation and energy sources where the cost of generated water can economically compete with other conventional sources. In regions such as Abu Dhabi, the idea of having small-scale dehumidification system where the energy demand is mostly met by solar radiation and the volume of generated water is freely controlled and managed by household seems appealing.

Paper to be presented at the 1991 ISES Solar World Congress, August 17 -24, 1991, Denver, Colorado, USA
In 1987 Arizona's governor announced a goal of constructing a solar powered community that would produce as much energy from the sun as it consumed. As a part of that program the use of a water cooled photovoltaic system evolved. The thermal energy would be utilized in homes with a district heating and desiccant cooling system. Thermal powered desiccant cooling was selected because it required water with relatively moderate temperatures, 140-1600F, that could be easily transported in insulated low-cost plastic pipe. Three ASK Corp. desiccant cooling/heating units have been successfully operated in the Phoenix area on a 5000 sq ft solar-powered residence since October, 1985. There also are photovoltaic/water cooled intermediate concentrators commercially available that have been thoroughly tested through different Department of Energy programs. This study describes the use of a computer to design a hybrid photovoltaic/thermal system providing heat to a district heating and desiccant cooling system for a 24 home subdivision in the Phoenix area of Arizona. Excess thermal energy is stored in an insulated pond. The gunite coated foam cover of the pond served as a tracking base for the concentrating solar collectors.

This research project was based on the Design, Implementation and Evaluation of a Photovoltaic Water heating system in South Africa, Eastern Cape Province. The purpose of the study was to design and investigate the scientific and economic contribution of direct water cooling on the photovoltaic module. The method involved performance comparison of two photovoltaic modules, one naturally cooled (M1) and the other, direct water cooled module (M2). Module M2 was used to produce warm water and electricity, hence, a hybrid system. The study focused on comparing the modules’ efficiency, power output and their performance. The temperatures attained by water through cooling the module were monitored as well as the electrical energy generated. A data logger and a low cost I/V characteristic system were used for data collection for a full year. The data were then used for performance analysis of the modules. The results of the study revealed that the directly water cooled module could operate at a higher electrical efficiency for 87% of the day and initially produced 3.63% more electrical energy each day. This was found to be true for the first three months after installation. In the remaining months to the end of the year M2 was found to have more losses as compared to M1 as evidenced by the modules’ performance ratios. The directly water cooled module also showed an energy saving efficiency of 61%. A solar utilization of 47.93% was found for M2 while 8.77% was found for M1. Economically, the project was found to be viable and the payback period of the directly cooled module (M2) system was found to be 9.8 years. Energy economics showed that the system was more sensitive to the price changes and to the energy output as compared to other inputs such as operation and maintenance and years of operation. A generation cost of R0.84/kWh from the system was found and when compared to the potential revenue of R1.18 per kWh, the system was found to enable households to make a profit of 40.5 %. Use of such a system was also found to be able to contribute 9.55% towards carbon emission reduction each year. From these results, it was concluded that a directly cooled photovoltaic/thermal heating (PV/T) system is possible and that it can be of much help in terms of warm water and electricity provision.

In 2013, the worldwide production of renewable electricity accounted for 22.1% of the total energy production with 0.9% coming from solar photovoltaics (PVs). Recently, there has been a growing interest for Cu2ZnSnS4 (CZTS) quaternary semiconductor due to the abundance and low cost of its precursors. Moreover, this chalcopyrite material has an ideal direct band gap around 1.5 eV, high absorption coefficient (α >104 cm-1) and high conductivity, making it suitable for nanostructured and dye-sensitized solar cell (DSSC) applications. Here, CZTS nanoparticles have been synthesized by pulsed laser deposition (PLD) and simultaneously deposited in the interstitial space of ZnO nanowire arrays to form bulk heterojunction 3D nanostructured solar cells. Secondly, vertically oriented CZTS nanoplates have been synthesized by PLD and used as counter electrode in platinum-free dye-sensitized solar cells. These CZTS nanostructures proved to be suitable in achieving workable solar cells, which could significantly cut down the cell cost and provide environmentally friendly photovoltaic devices. Alternately, hybrid organic–inorganic perovskite solar cells have become one of the most attractive photovoltaic technologies with easy solution fabrication and high conversion efficiencies. However, the devices remain unstable under certain processing and environmental conditions. Herein, formamidinium lead tri-halide perovskite (FAPbI3) planar heterojunction solar cells have been fabricated under a controlled environment. The fabrication parameters (precursor concentration, annealing, etc) and the effect of humidity on the structural, optical, and electrical properties of FAPbI3 thin films and devices have been investigated and proved to be critical in the processing of efficient devices. Solar cells with conversion efficiency of 16.6% have been obtained. Furthermore, in-situ techniques such as in-situ (scanning) transmission electron microscopy and in-situ XRD were performed to understand the crystallization and degradation mechanisms of FAPbI3 thin films.The in-situ data were correlated with planar heterojunction FAPbI3 devices efficiency data in order to improve the device fabrication process.

The performance of parabolic trough based solar power plants over the last 25 years has proven that this technology is an excellent alternative for the commercial power industry. Compared to conventional power plants, parabolic trough solar power plants produce significantly lower levels of carbon dioxide, although additional research is required to bring the cost of concentrator solar plants to a competitive level. The cost reduction is focused on three areas: thermodynamic efficiency improvements by research and development, scaling up of the unit size, and mass production of the equipment. The optimum design, performance simulation and cost analysis of the parabolic trough solar plants are essential for the successful implementation of this technology. A detailed solar power plant simulation and analysis of its components is needed for the design of parabolic trough solar systems which is the subject of this research. Preliminary analysis was carried out by complex models of the solar field components. These components were then integrated into the system whose performance is simulated to emulate real operating conditions. Sensitivity analysis was conducted to get the optimum conditions and minimum levelized cost of electricity (LCOE). A simplified methodology was then developed based on correlations obtained from the detailed component simulations. A comprehensive numerical simulation of a parabolic trough solar power plant was developed, focusing primarily on obtaining a preliminary optimum design through the simplified methodology developed in this research. The proposed methodology is used to obtain optimum parameters and conditions such as: solar field size, operating conditions, parasitic losses, initial investment and LCOE. The methodology is also used to evaluate different scenarios and conditions of operation. The new methodology was implemented for a 50 MWe parabolic trough solar power plant for two cities: Tampa and Daggett. The results obtained for the proposed methodology were compared to another physical model (System Advisor Model, SAM) and a good agreement was achieved, thus showing that this methodology is suitable for any location.

This thesis presents investigations on air-cooled air gap membrane distillation for desalination and the application of radial waveguides based on total internal reflection for solar thermal desalination. Using an air-cooled design for an air gap membrane distillation (AGMD) process may result in significantly lower energy requirements for desalination. Experiments were conducted on AGMD module to study the effect of air gap, support mesh conductivity and hydrophobicity, condensing surface hydrophobicity. A novel modular design was used in which modules could be used in a series configuration to increase the flux value for the distillate. The output from the series configuration was found to have about three times the production from a single pass water-cooled system with the same temperature difference between the saline and clear water streams. The results also indicated that the mesh conductivity had a favorable effect on the flux value whereas the hydrophobicity of the mesh had no significant effect. The hydrophobicity of the condensing surface was favorable on two accounts: first, it led to an increase in the flux of the distillate at temperatures below 60 °C and second, the temperature difference of the saline feed when it enters and leaves the module is lower which can lead to energy savings and higher yields when used in a series configuration. The second part of the thesis considers use of low-cost radial waveguides to collect and concentrate solar energy for use in thermal desalination processes. The optical-waveguide-based solar energy concentrators are based on total internal reflection and minimize/eliminate moving parts, tracking structures and cost. The use of optical waveguides for thermal desalination is explored using an analytical closed-form solution for the coupled optical and thermal transport of solar irradiation through a radial planar waveguide concentrator integrated with a central receiver. The analytical model is verified against and supported by computational optical ray tracing simulations. The effects of various design and operating parameters are systematically investigated on the system performance, which is quantified in terms of net thermal power delivered, aperture area required and collection efficiency. Design constraints like thermal stress, maximum continuous operation temperature and structural constraints have been considered to identify realistic waveguide configurations which are suitable for real world applications. The study provides realistic estimates for the performance achievable with radial planar waveguide concentrator-receiver configuration. In addition to this, a cost analysis has been conducted to determine the preferred design configurations that minimize the cost per unit area of the planar waveguide concentrator coupled to the receiver. Considering applications to thermal desalination which is a low temperature application, optimal design configuration of waveguide concentrator-receiver system is identified that result in the minimum levelized cost of power (LCOP).
Master of Science

Os fornos solares do tipo caixa têm sido ensaiados de acordo com procedimentos [1, 2], propostos para constituírem uma norma de ensaios. Estes procedimentos baseiam-se em definições e medidas com caraterísticas que não cumprem cabalmente o objetivo. Nesta dissertação propõe novos coeficientes para avaliar a performance dos fornos solares de tipo caixa, que têm em conta, de uma forma completa, as distintas características físicas dos mesmos, considerando a inclinação do vidro da cobertura, as variações das suas áreas de captação da radiação solar com a variação sazonal do sol. Em particular procura eliminar a dependência dos ensaios com a altura do ano em que são realizados (sazonalidade). Os resultados obtidos permitiram ainda propor um novo coeficiente (o tempo até à ebulição) verdadeiramente útil para a comparação direta entre fornos. Com estes resultados conclui-se que os novos coeficientes possuem características para poderem integrar uma proposta de uma futura norma de ensaios; Abstract Study of new procedures for the testing of box-type solar cookers for food confectionery Box-type solar cookers have been tested according to procedures [1, 2] proposed to constitute a test standard. These procedures are based on definitions and measurements with characteristics that don’t meet their objective. In this dissertation we propose new figures of merit to evaluate the performance of a box-type solar cooker, which take into account different physical characteristics of the solar cookers, considering inclination of the cover glass and the variations of its area to incoming beam radiation with the seasonal variation of the sun’s height. In particular, it seeks to eliminate the dependence with time of the year tests are carried out (seasonality). The results obtained allowed for a new coefficient (time to boiling) to be proposed, which is truly useful for the direct comparison between solar cookers. With these results we conclude that the new coefficients have the right characteristics to integrate a proposal for a future test standard.

Increasing energy use has caused many environmental problems including global warming. Energy use is growing rapidly in developing countries and surprisingly a remarkable portion of it is associated with consumed energy to keep the temperature comfortable inside the buildings. Therefore, identifying renewable technologies for cooling and heating is essential. This study introduced applications of steel sheets integrated into the buildings to save energy based on existing technologies. In addition, the proposed application was found to have a considerable chance of market success. Also, satisfying energy needs for space heating and cooling in a single room by using one of the selected applications in different Köppen climate classes was investigated to estimate which climates have a proper potential for benefiting from the application. This study included three independent parts and the results related to each part have been used in the next part. The first part recognizes six different technologies through literature review including Cool Roof, Solar Chimney, Steel Cladding of Building, Night Radiative Cooling, Elastomer Metal Absorber, and Solar Distillation. The second part evaluated the application of different technologies by gathering the experts’ ideas via performing a Delphi method. The results showed that the Solar Chimney has a proper chance for the market. The third part simulated both a solar chimney and a solar chimney with evaporation which were connected to a single well insulated room with a considerable thermal mass. The combination was simulated as a system to estimate the possibility of satisfying cooling needs and heating needs in different climate classes. A Trombe-wall was selected as a sample design for the Solar Chimney and was simulated in different climates. The results implied that the solar chimney had the capability of reducing the cooling needs more than 25% in all of the studied locations and 100% in some locations with dry or temperate climate such as Mashhad, Madrid, and Istanbul. It was also observed that the heating needs were satisfied more than 50% in all of the studied locations, even for the continental climate such as Stockholm and 100% in most locations with a dry climate. Therefore, the Solar Chimney reduces energy use, saves environment resources, and it is a cost effective application. Furthermore, it saves the equipment costs in many locations. All the results mentioned above make the solar chimney a very practical and attractive tool for a wide range of climates.

碩士
國立臺灣科技大學
設計研究所
101
Behind the appearance of the continuous progress of mankind, the crisis of excessive energy consumption and environmental destruction is hidden, and the use of renewable energy has become the only way which must be passed for sustainable development. Among numerous renewable energies, the precious features of solar thermal energy have tremendous chances and benefits for products design. Taking the design of solar thermal cooker as example, it does not need to consume other resources for making fire, and it will not produce harmful combustion exhaust gas and ash. Such cooker is used by transferring “the heat of sun” into “the heat for cooking”, which is natural, environmentally friendly and very economical. In addition, for the third world countries, such kind of cooker serves as an affordable alternative which does not only meet the cooking needs, but can solve the problems like that fuel is difficult to be obtained and ashes has bad effects on human health. Its importance can not be ignored. If such necessities with application of renewable energy can be promoted, high value shall be generated in the sense of environmental protection. This thesis started from literature review on solar radiation, heat collecting technology and cooking principles, and it assembled cases of solar thermal cooker for cross-analysis in order to explore the opportunities for further development and to develop new kind of concept prototypes. During the design process, it was dedicated to present through design methods and experimental spirit by repeating validation tests and finally used two works, “Solar cooker for disaster area” and “Solar pot”, for interpretation: (1) chances for solar thermal cooker to be applied in different situations; (2) to improve the problems on different aspects of the existing solar thermal cooker and explore the possibility for it to be accepted by more people. The results of this thesis are: by applying the miniaturization of green energy technology into creative product design, contribution can be made to the environment, and certain assistance can be brought to the users.

碩士
崑山科技大學
機械工程研究所
97
Mechanical engineering development requires tools and validation methods to prove its functionality, by this research project is expected to contribute indirectly with future works illustrating the application of a simplified Quality Function Deployment methodology, encouraging researches to maximize all the available resources to support its results, the main purpose for this investigation is to demonstrate both procedures and benefits of quality function deployment as a complementary feasible tool to enhance the product design task. The analysis of customer needs, engineering characteristics and house of quality as the first of four stages in the QFD process is performed in the evaluation of a product already developed, specifically in this case, one of the solar cookers that Kun Shan University possess for research purposes. The validity of QFD for any kind of manufacturing or service industry makes the methodology an attractive and achievable complement. The results and contributions of the methodology in the year 2009 allows an analysis of the results obtained from the assessment in order to improve the characteristics of a product designed to compete in the new alternate energy field which is looking to establish a balance to improve the current process development efficiency, during the research the obstacles were present in the form of insufficient time and the impossibility of the concurrent engineering implementation.

Large percentages of the South African population have no access to grid power and are located at distances that make provision for such facility uneconomical. Also traditional fuels are under pressure. Most areas in South Africa receive 300 days of sunshine per year. The proposed solar system addresses the needs of such communities. A solar thermal energy storage system utilizing phase change material has been proposed that can overcome the time mismatch between solar availability and demand. The system consists of two types of thermal heat storage. The latent heat storage used Phase Change Materials (PCM) which melts at a sufficiently high temperature for cooking a variety of food types. By choosing a suitable PCM to take advantage of the latent heat absorbed during phase changes. Heat losses from both the latent heat storage and condenser are captured in the surrounding sensible heat store. The objective of this project to develop a prototype modules which together as a system could provide the essential domestic power requirements of the target groups. This includes power for cooking, hot water and in addition a limited electrical power supply for the system itself as well as for other minor loads.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.

碩士
崑山科技大學
機械工程研究所
99
Innovation has become a key factor not only in the success of a firm but also in its survival in our globalized and changing economy. As the Innovation and Enterprise Team asserts in its report: “In difficult economic times, firms need to adapt if they are going to survive. Innovation is particularly important at such times” (Innovation and Enterprise Team, 2009). Universities and research centers are big contributors to as generators of knowledge, technology and innovations for firms and/or for their own. At the same time the transformation of that knowledge and technology into a commercialized innovative product is a crucial factor in obtaining revenue for the success, survival and continuous grow of firms, as well as a crucial factor in obtaining revenue and financial resources for universities in order to maintain, expand and improve their researches. It is as crucial as the challenge it represents to move from the idea to the market, from the technology to a commercialized product. The commercialization of a new innovative product represents a big challenge, beginning from the fact that inventions and innovations had reported to have big rates of failing when it comes to succeed in the market place. According to (Udell, 2007), new product failure rate vary significantly, ranging from a low of 20 percent to a high of 85 percent Moreover, new technologies, inventions and innovations never reach the marketplace, dying in advance without having the opportunity to demonstrate their potential, even when it could be such a useful product by improving the quality of life of this world. Unfortunately, that is the case of some of the new green energy technologies that have being developed within universities, technologies that regardless its potential to reduce and optimize present and future environmental, monetary and social cost, never reach the market place, and thus not being properly diffused and without generating any kind of revenue. This thesis, addresses a study on the factors that affect the commercialization of an innovative product. The study also consider some aspects in one of the innovations developed in the college of engineering of Kun Shan University, a Solar Energy Cooker (SEC), which is on the line with the efforts that the university is doing to develop and promote technologies that use and take advantages of the clean energies such as Solar energy as a fuel to generate heat, in this case for cooking. The factors that affect the successful commercialization are studied through a literature review of previous studies about commercialization of patent products, inventions, innovative products, new products, etc. At the same time, it makes a brief review on previous commercialization models. After the identification of the factors that affect the process of commercialization, a selection of the most significant is done in order to take the most important and evaluated them. Later on, based on the evaluation of those factors and the literature review an existing commercialization model is adapted to be proposed as a guide for the commercialization of an innovative product. Finally, the factors and elements that are used to construct the proposed commercialization model are evaluated and validated. Conclusions and recommendations are presented to close this study.

博士
國立臺北教育大學
自然科學教育學系
107
This study aims to use the six self-developed teaching activities on “Solar Cooker Curriculum” and “Food and Agriculture Curriculum”. The STEAM (Science, Technology, Engineering, Arts & Mathematics) and NGSS (Next Generation Science Standards) were used to design the Environmental Education of Direction Governing for the 12-Year Basic Education Curricula. In order to discuss the effects of these teaching activities on sixth grade students, this study adopts single group pre-test and post-test design, which are both qualitative and quantitative studies. The subjects are 106 elementary school sixth graders. Quantitative research tools include “Environmental Education Themes Scale for Elementary School Students” and qualitative methods include questionnaires, value clarification activities, activity logs, journals, semi-structural interviews, and teachers’ reviews. The results indicated that the former “Environmental Education Themes Scale for Elementary School Students” are higher than the latter scale. Through the instructional activities of the Solar Cooker Curriculum” and “Food and Agriculture Curriculum” the overall environmental learning subjects was enhanced of elementary school senior grade students, and promoting environmentally conscious behaviors and their interests in environmental learning.

碩士
國立高雄第一科技大學
機械與自動化工程所
96
The solar-cell thermoelectric cooler embedded in the air conditioner system for providing with a cool source to further improve the cooling efficiency of the inverter air conditioner system will be investigated in this thesis. The solar-cells are used to drive the thermoelectric cooler by using pulse width modulation (PWM). In addition, a novel orthogonal particle swarm optimization (OPSO) is used to maximize the output power of solar cells. In the inverter air-conditioner system, a power factor corrector (PFC) is used to correct the input current to be a sinusoidal waveform to further improve power quality. Furthermore, the PFC can also be used to increase the DC link voltage. The increased DC link voltage is useful for the PWM driving of the inverter. Accordingly, the total harmonic distortion (THD) of the power source will be improved by using the PFC. And the control loop to control thermoelectric cooler helps to save the power consumption for the inverter air conditioner system. The design of experiments (DOE) will be employed to find out the minimum output power for the inverter air conditioner system.

碩士
臺灣大學
機械工程學研究所
98
A solar-assisted ejector cooling/heating system (SACH-k1) was developed in the present study. SACH-k1 includes three systems, ejector cooling system, inverter-type air conditioner and solar heating system. The cooling effect of ECS generated by solar heat is used to cool the condenser of the A/C, then increase A/C’s COP and reduce the power consumption of the compressor. It has been noted that ejector cooling system should be designed using an air-cooled condenser in hot climate area because of the water shortage. Thus, SACH-k1 is developed for this purpose and the design details are shown in paper. To utilize solar energy, the liquid level of SACH’s generator needs to be controlled precisely. A liquid level control system is developed in the present study, so that SACH can overcome unstable effect due to generator temperature changes caused by variation of solar irradiation. Further, running cost of ejector cooling system is too high to apply. This study proposes the idea of ejector’s backpressure optimal control and realizes the idea by the optimal control system. As a result, the operating power consumption is decreased about 60%.