Estudo do desempenho de um coletor solar flexível de baixo custo

Dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáO presente trabalho teve como objetivo desenvolver o projeto e simular o comportamento e desempenho de um coletor solar flexível de baixo custo. O projeto almejou desenvolver um coletor modular, flexível e com materiais de baixo custo para facilitar o transporte, ampliar a variedade de superfícies em que pode ser instalado e reduzir os gastos de aquisição. As características geométricas do coletor foram definidas com nove canais para conduzir o fluido ao longo da placa (denominados canais de aquecimento, com 1000 mm de comprimento, 70 mm de largura e 10 mm de espessura), um canal de distribuição e um canal de coleta de 40 mm de largura, cada um acoplado nas extremidades dos canais de aquecimento. O vão entre a superfície absorvedora e uma camada transparente fixada na parte superior é de 10 mm. Estas dimensões foram acordadas depois de pesquisas e de reuniões com uma empresa de manufatura de materiais insufláveis. Devido as suas boas propriedades térmicas e seu preço acessível, o material escolhido para compor a camada de cobertura e a placa absorvedora foi o filme de Poliuretano (PU) com proteção contra raios ultravioletas. Já para a camada isolante inserida na parte inferior da placa, o material selecionado foi a espuma elastomérica à base de borracha Etileno-Propileno-Dieno-monômero (EPDM) com 19 mm de espessura. Simulou-se o coletor acoplado a um sistema de aquecimento de água contendo tubagens de condução e um reservatório cilíndrico de 150 L isolados termicamente. O sistema foi simulado no software ANSYS® sob cinco condições diferentes. As três primeiras referem-se a estudos numa zona temperada, onde é necessário o uso de água aquecida o ano todo e correspondem às estações de verão, outono e inverno do Porto, em Portugal. As quarta e quinta situações foram realizadas em Fortaleza e Rio de Janeiro, no Brasil, e por já estarem situadas em zonas tropicais, considerou-se que o uso de água aquecida seria necessária apenas no inverno. Para cada local foi usado o fluxo solar das respectivas zonas. A situação mais gravosa, na nossa análise o inverno no Porto devido aos baixos valores de radiação solar, obteve uma temperatura de 30,9 ºC na água de uso ao fim do dia. Fortaleza e Rio de Janeiro obtiveram temperaturas de 35,3 ºC e 38,0 ºC, respectivamente. Em seguida foi acoplada mais uma placa absorvedora no sistema onde a máxima temperatura da água de uso retornada pelas simulações foi de 40,2 ºC para o inverno do Porto, 49,1 ºC em Fortaleza e 52,4 ºC no Rio de Janeiro. Num cenário onde haja consumo de água aquecida ao longo do dia, pôde-se concluir que é necessário no Porto um sistema contendo três placas coletoras ligadas em série, enquanto que Fortaleza e Rio de Janeiro, duas placas são suficientes para reduzir os gastos com aquecimento de água dentro de uma residência. Realizou-se uma média entre as eficiências dos sistemas de uma placa de cada simulação e pôde-se concluir que o projeto se torna interessante por apresentar uma eficiência média de 75%, cerca de 15% maior que os coletores solares de polímero encontrados na literatura.The present project had as objective to develop and to simulate the behavior and performance of a flexible low cost solar collector. The project aimed to develop a modular, flexible, with low-cost materials collector to facilitate transportation, to expand the variety of surfaces on which it can be installed, and to reduce acquisition costs. The geometric characteristics of the collector were defined with nine ducts to conduct the fluid along the plate (called heating ducts, 1000 mm long, 70 mm wide and 10 mm thick), a distribution duct and a collection duct 40 mm wide, each one coupled at the ends of the heating ducts. The gap between the absorber surface and a transparent layer attached to the top is 10 mm. These dimensions were agreed after researches and meetings with a manufacturing company of inflatable materials. Due to its good thermal properties and its affordable price, the material chosen to compose the cover layer and the absorber plate was the Polyurethane (PU) film with protection against ultraviolet rays. For the insulation layer inserted in the lower part of the plate, the selected material was elastomeric foam based on Ethylene-Propylene-Diene-monomer (EPDM) rubber with 19 mm of thickness. The collector coupled to a water heating system containing driving pipes and a cylindrical reservoir with 150 L thermally insulated was simulated. The system was simulated in the ANSYS® software under five different conditions. The first three conditions refer to studies in a temperate zone, where it is necessary to use heated water all over the year and correspond to the summer, autumn and winter seasons of Porto, in Portugal. The fourth and fifth situations were carried out in Fortaleza and Rio de Janeiro, in Brazil, and because they were already located in tropical zones, it was considered that the use of heated water would be necessary only in the winter. For each site was used the solar flux of the respective zones. The most critical situation, in our analysis the winter in Porto due to the low values of solar radiation, obtained a temperature of 30.9 ºC in the water of use at the end of the day. Fortaleza and Rio de Janeiro obtained temperatures of 35.3 ºC and 38.0 ºC respectively. Then, another absorber plate was coupled to the system where the maximum temperature of the water returned by the simulations was 40.2 ºC for the winter of Porto, 49.1 ºC in Fortaleza and 52.4 ºC in Rio de Janeiro. In a scenario where there was a consumption of heated water throughout the day, it was concluded that a system with three collector panels connected in series is necessary in Porto, while in Fortaleza and Rio de Janeiro, two plates are sufficient to reduce water-heating costs inside a residence. An average efficiency between the systems with one plate of each simulation was obtained and it was concluded that the design becomes interesting because it presents an average efficiency of 75%, which is about 15% higher than the polymer solar collectors found in the literature

On confluence and contestation in the Orinoco interaction sphere: the engraved rock art of the Atures Rapids

The Atures Rapids have long been considered a major point of confluence in the Middle Orinoco landscape, Venezuela. This has been underlined by newly discovered rock art panels on islands within the Rapids and on the margins of the Orinoco River. The panels were recorded photographically and photogrammetrically, and the spatial organisation and taphonomic factors affecting the corpus were investigated. The rock art was also examined in the context of established models of chronology and authorship. Placing the corpus in relation to archaeological and ethnographic evidence from Amazonia and the Guianas emphasises how the Atures Rapids structured pre-Columbian and Colonial contact between diverse groups in lowland South America

Patterns of Style, Diversity, and Similarity in Middle Orinoco Rock Art Assemblages

The area encompassed by the Orinoco river basin is home to some of the largest and most diverse rock art sites in lowland South America. In this paper, we aim to formally describe the spatial distribution and stylistic attributes of rock engravings and paintings on both banks of the Orinoco, centred on the Átures Rapids. Drawing on an exhaustive literature review and four years of field survey, we identify salient aspects of this corpus by investigating patterns of diversity and similarity. Based on a stylistic classification of Middle Orinoco rock art, this permits us to discuss potential links, as well as notable discontinuities, within the assemblage and possibly further afield. We consider the theoretical implications of our work for the study of pre-Columbian art and conclude with some suggestions for advances in methods for achieving the goal of deriving broader syntheses

Desenvolvimento de um coletor solar flexível e de baixo custo

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMO: Esse trabalho reporta o desenvolvimento numérico de um coletor solar flexível e de baixo custo e a posterior fabricação de protótipos, em filme de poliuretano (PU). Foram projetados quatro modelos de coletores solares no software SolidWorks® e realizadas simulações no software ANSYS/FluentTM 18.2; os estudos de fabricação dos modelos foram realizados em conjunto com uma empresa de construção de insufláveis. O desempenho do sistema foi simulado para um coletor e depois para dois coletores, nas condições de inverno das cidades do Porto e de Fortaleza. O coletor forneceu água quente para uso a temperaturas próximas a 40ºC. Foi fabricado um protótipo que é flexível e de baixo custo para ser testado o seu desempenho térmico.ABSTRACT: These paper reports the development of a flexible and low-cost solar collector and posterior prototype manufacturing, in polyurethane film. Four models of solar collectors were designed in SolidWorks® software and simulated in ANSYS/FluentTM 18.2 software; the manufacturing studies of the models were carried out together an inflatable construction company. The systems were simulated for a collector and for two collectors in the winter conditions in the cities of Porto and Fortaleza. The collector provided hot water for use at approximately 40ºC. A low-cost and flexible prototype was manufactured and it´s thermal performance will be tested.info:eu-repo/semantics/publishedVersio

A Case of Schizophrenia Complicated in Subacute Combined Degeneration: How Nutrition Affects Physical Health in Psychotic Patients

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An Italian functional genomic resource for Medicago truncatula

Background: Medicago truncatula is a model species for legumes. Its functional genomics have been considerably boosted in recent years due to initiatives based both in Europe and US. Collections of mutants are becoming increasingly available and this will help unravel the genetic control of important traits for many species of legumes. Findings: Our report is on the production of three complementary mutant collections of the model species Medicago truncatula produced in Italy in the frame of a national genomic initiative. Well established strategies were used: Tnt1 mutagenesis, TILLING and activation tagging. Both forward and reverse genetics screenings proved the efficiency of the mutagenesis approaches adopted, enabling the isolation of interesting mutants which are in course of characterization. We anticipate that the reported collections will be complementary to the recently established functional genomics tools developed for Medicago truncatula both in Europe and in the United States