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Abstract(s)
A radiação solar absorvida pela Terra desde que entra na atmosfera é de tal ordem de grandeza que bastaria uma hora de energia solar para suprir as necessidades de consumo energético para um ano inteiro (valores de 2002). Por outras palavras, um ano de energia solar, se utilizada na totalidade, é superior à energia alguma vez produzida usando combustíveis convencionais como carvão, urânio, crude, etc. Com o aumento das necessidades de consumo energético devido ao crescimento da população mundial, a energia produzida mundialmente com recurso a combustíveis convencionais aumentou 97 vezes desde 2004. De acordo com previsões da Agência Internacional de Energia Solar, em 2050 a utilização de energia solar contribuirá em cerca de 27% para a produção energética a nível mundial. A escassez de água potável é um problema cuja resolução é vital para a vida humana. Esta problema está a alastrar por todo o globo devido às mudanças climáticas, que provocam secas em locais onde não existiam anteriormente. Normalmente é um problema que vem acompanhado pela falta de rede elétrica e dificuldades económicas. Assim, o uso de processos de purificação de água com base em formas renováveis de energia é mais apelativo, na maior parte dos casos em que há escassez de água. Sabe-se que os patógenos podem ser eliminados aquecendo a água até uma temperatura superior a 100ºC. O projeto desenvolvido pretende estudar a possibilidade de purificar água, com recurso à energia solar disponível. O foco principal é analisar o projeto construtivo de coletores híbridos (fotovoltaicos e térmicos) e entender os requisitos para a sua boa performance. Parâmetros operacionais como temperatura do painel, temperatura da célula fotovoltaica, ou caudal de fluido térmico serão analisados, por forma a selecionar um parâmetro crítico. Serão abordadas métricas de performance como eficiência térmica, elétrica e eficiência de acordo com a 1ª e 2ª leis da termodinâmica, que serão integradas numa rotina de cálculo desenvolvida com Excel. Os resultados obtidos serão discutidos, por forma a obter as conclusões. O comportamento da temperatura atingida pela água é também estudado e discutido, bem como a possibilidade de aumentar essa temperatura com um coletor deste tipo. Através deste projeto, elementos críticos necessários para analisar e projetar um coletor solar híbrido são identificados. O estudo foi conduzido, identificando os fatores que promovem o aumento da temperatura da água. Verificou-se que os valores de eficiência associados são reduzidos, se bem com o aumento da temperatura pretendido.
It is believed that one hour of the total solar energy received by the earth´s surface is of the same order of magnitude as total world consumption of non-renewable fuel for one whole year (2002 values). In other words, one year of solar energy, if completely utilized, it is more than the energy produced ever by the conventional fuels like coal, uranium, crude, etc. With the increase in demand of energy due to growth in human population, currently world is producing energy using conventional fuels around 97 times than we produced since 2004. According to the International Solar Agency prediction, by 2050 using solar energy will contribute about 27% of the whole energy production in the world. Scarcity of potable water is a problem whose resolution is vital to human life. It is becoming more widespread all over the globe due to the climate changes, that cause droughts in places where they did not previously exist. This problem is often accompanied by the absence of the grid and economic difficulties. Thus, the use of water purification processes that rely on renewable forms of energy is more appealing, in most of the cases of potable water scarcity. It is understood that, by increasing the temperature to more than 100 ºC shall kill the pathogens in the water. Thereby impure water becomes consumable. This project aims to study the possibility of water purification using the available solar energy. The main focus is to look into the design of hybrid photovoltaic/thermal (PVT) solar collectors and to understand the requirements for its performance. The operational parameters such as Inlet fluid teperature, outlet temperature, ambient teperature, solar radiance and etc, are to be critically analysed, discussed in order to propose an efficient design parameter. Performance metrics like thermal efficiency and electrical efficiencywill be approached. Thereby, related formulas to those performance metrics are framed. These formulas are solved using EXCEL. It is then plotted into graphs and discussed to know the output. Hence, values are given accordingly to the parameters. The behaviour of temperature parameter with efficiency values are studied and discussed. The understanding of possibility of increasing the water temperature is done as well. Through this project, critical elements required to design and analyse a solar PVT model are identified. The study was conducted and understood the components that help in increasing the temperature. Therefore, the efficiency values achieved are very low though there is a peak increase the temperature.
It is believed that one hour of the total solar energy received by the earth´s surface is of the same order of magnitude as total world consumption of non-renewable fuel for one whole year (2002 values). In other words, one year of solar energy, if completely utilized, it is more than the energy produced ever by the conventional fuels like coal, uranium, crude, etc. With the increase in demand of energy due to growth in human population, currently world is producing energy using conventional fuels around 97 times than we produced since 2004. According to the International Solar Agency prediction, by 2050 using solar energy will contribute about 27% of the whole energy production in the world. Scarcity of potable water is a problem whose resolution is vital to human life. It is becoming more widespread all over the globe due to the climate changes, that cause droughts in places where they did not previously exist. This problem is often accompanied by the absence of the grid and economic difficulties. Thus, the use of water purification processes that rely on renewable forms of energy is more appealing, in most of the cases of potable water scarcity. It is understood that, by increasing the temperature to more than 100 ºC shall kill the pathogens in the water. Thereby impure water becomes consumable. This project aims to study the possibility of water purification using the available solar energy. The main focus is to look into the design of hybrid photovoltaic/thermal (PVT) solar collectors and to understand the requirements for its performance. The operational parameters such as Inlet fluid teperature, outlet temperature, ambient teperature, solar radiance and etc, are to be critically analysed, discussed in order to propose an efficient design parameter. Performance metrics like thermal efficiency and electrical efficiencywill be approached. Thereby, related formulas to those performance metrics are framed. These formulas are solved using EXCEL. It is then plotted into graphs and discussed to know the output. Hence, values are given accordingly to the parameters. The behaviour of temperature parameter with efficiency values are studied and discussed. The understanding of possibility of increasing the water temperature is done as well. Through this project, critical elements required to design and analyse a solar PVT model are identified. The study was conducted and understood the components that help in increasing the temperature. Therefore, the efficiency values achieved are very low though there is a peak increase the temperature.
Description
Keywords
Energia solar Produção de energia Água potável Purificação de água Eficiência energética Coletor PVT Solar energy Energy production Potable water Water purification Energetic efficiency Photovoltaic/thermal collector