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- Modeling multi effect distillation powered by CSP in TRNSYSPublication . Casimiro, Sergio; Cardoso, João P.; Alarcón-Padilla, Diego-César; Turchi, Craig; Ioakimidis, C.; Mendes, J. FarinhaThis work presents the results of using a new tool to simulate the cogeneration of water and electricity with Concentrating Solar Power (CSP) and Forward Feed Multi-Effect-Desalination (FF-MED) plants, by adding a new functionality to the System Advisor Model (SAM) developed by the US National Renewable Energy Laboratory (NREL). The controlling strategy of the MED model is presented in detail, and a case study application is shown. This study compares the results obtained with a CSP plant operating in San Diego, CA, with four different cooling systems: an MED/Seawater Cooling Circuit (SWCC), dry cooling, wet cooling, and a SWCC standalone. The results show that the usage of an MED/SWCC system in cogeneration with a CSP plant can be feasible and has the potential to be economically interesting.
- Solid-gas reactors driven by concentrated solar energy with potential application to calcium looping: A comparative reviewPublication . Rivero, Mayra Alvarez; Rodrigues, Diogo; Pinheiro, Carla I.C.; Cardoso, João P.; Mendes, Luís FilipeABSTRACT: The calcium looping process, based on the reversible calcination-carbonation reaction cycle of CaCO3-CaO, is an emerging and promising technology for thermochemical energy storage in concentrating solar power plants. In this process, concentrated solar energy is used to carry out the endothermic solar-driven calcination of CaCO3 with formation of CaO and CO2 as products in a solid-gas reactor. In this review, a number of experimental studies of solid-gas reactors driven by concentrated solar energy are discussed, with a particular focus on solar reactors for calcination of CaCO3 or with that potential application. The solid-gas reactors for solar-driven calcination of CaCO3 reported in the literature achieved a total efficiency of 16.6%-88% for a mass flow rate up to 25 kg h(-1) and a power up to 55 kW. Also, a detailed comparison of the different types of solid-gas reactors driven by concentrated solar energy is provided by outlining their advantages and disadvantages according to several relevant criteria. This review is intended to be a valuable tool for the selection of a reactor configuration for future studies related to solar-driven calcination of CaCO3.
- New functionalities for the Tonatiuh ray-tracing softwarePublication . Cardoso, João P.; Mutuberria, Amaia; Marakkos, Costas; Schoettl, Peter; Osório, Tiago; Les, IñigoABSTRACT: Tonatiuh is an open source, freeware, Monte Carlo ray tracer suitable for CST applications, and is currently under further development to to increase and improve its functionalities. Work has recently been performed to implement the following functionalities: a flux distribution calculation utility; materials with incidence angle dependent optical properties; and the ability to import 3D geometries from CAD files. This paper provides a detailed account of these new functionalities, and the tests performed to establish their correct implementation in the new software version, Tonatiuh v 2.2.3
- Estimativa de potenciais técnicos de energia renovável em Portugal: eólico, solar fotovoltaico, solar concentrado, biomassa e oceanosPublication . Simoes, Sofia; Simões, Teresa; Barbosa, Juliana; Rodrigues, Carlos; Azevedo, Pedro; Cardoso, João P.; Facão, Jorge; Costa, Paula Silva; Justino, Paulo Alexandre; Gírio, Francisco; Reis, Alberto; Passarinho, Paula; Duarte, Luís C.; Moura, Patrícia; Abreu, Mariana; Estanqueiro, Ana; Couto, António; Oliveira, Paula; Quental, Lídia; Patinha, Pedro; Catarino, Justina; Picado, AnaExecutive Summary: There is a clear need to accelerate the energy transition, including the implementation of renewable electricity production plants, as well as the increase in consumption of other renewable energy carriers in buildings, industry, transport and other sectors. This work provides key information to make this transition possible, that is, the technical renewable energy potentials for Portugal. The aim is thus to contribute to policy support, as well as to decision-making by various Portuguese stakeholders (public and private) in the domains of energy, energy transition and greenhouse gases emissions mitigation. The work presents the technical renewable energy potentials for Portugal to: (i) decentralized solar photovoltaic (PV) plants in artificialized (or built-up) areas; (ii) centralized solar PV plants in non-artificialized (or natural) areas; (iii) concentrated solar power; (iv) onshore wind; (v) offshore wind (floating and fixed); (vi) bioenergy, and (vii) solar thermal. The wave energy primary energy resource potential is also presented (not the technical potential). The technical potential values of renewable energy sources (RES) presented are dynamic values, given the substantial uncertainty associated with their estimation. The study identifies technical RES potentials i.e., the technically viable energy generation achievable from a specific technology, considering the primary energy resource available and the geographic, environmental and land use limitations. RES economic potentials represent the fraction of RES technical potential that is economically viable, but they are not presented in this work. Likewise, this report does not address market potential, that translate the capacity and energy generation that the market effectively manages to implement. The presented RES technical potentials include the total capacity currently installed in the country. The technical potentials are estimated mostly for mainland Portugal, in most cases with a spatial disaggregation of at least NUT2 and sometimes for NUT5 and/or type of building. Despite adopting an approach based on a territorial analysis in which some areas of the country are excluded, this potential does not correspond to the work done in mapping less-sensitive areas towards future definition of RES “Go-To Areas”. The decentralized solar PV potential in artificialized areas is divided into 6 area types: industrial areas; commercial buildings; residential and mixed-use buildings; villas; health, education, cultural, tourist and military buildings, and other land uses (including parking lots and patios, ports, waste and wastewater treatment infrastructure, sports facilities, among others). It is estimated a technical potential of 23.33 GW that could generate up to 36.84 TWh/year. This potential is distributed throughout the entire territory of mainland Portugal but is higher in the North and Center regions. The RES technical potential for centralized solar PV was estimated as a range of values that translate the uncertainty associated with using different levels of concern in excluding certain areas in which solar PV can be deployed (for example to safeguard ecosystems, water resources, agriculture or archaeological heritage). The centralized solar PV potential varies between 168.82 GW and 45.63 GW. The maximum threshold of installed capacity could generate 278.11 TWh/year of electricity. The value is high and reflects on the one hand, the excellence of the solar resource throughout the country, and on the other, the large size of the considered areas. The CSP potential is 62.6 GW with a corresponding electrical production potential of 183.61 TWh/year. It is mainly located in the Alentejo region, although other areas have also been identified in other regions of the country. The wind onshore technical potential is 15.7 GW, that could generate 37.13 TWh/year, taking into account the safeguarding of various areas for the protection of ecosystems and also social acceptability issues. In the case of offshore wind and considering a capacity density of 4 MW/km2 for floating offshore and 5.5 MW/km2 for fixed offshore, a total of 36 GW and 2 GW are obtained, respectively. This capacity could generate up to 126.14 TWh/year (floating offshore) or 6.31 TWh/year (fixed offshore). The solar thermal energy potential focused residential and service buildings (such as nursing homes, barracks, etc., tourism, hospitals, indoor swimming pools and other sports facilities). The potential is of 0.95 GWt and 0.95 TWh/year for service buildings, 7.26 GWt and 5.84 TWh/year for residential buildings. For industry there is a potential of 1.06 GWt, which could generate up to 1.15 TWh/year for applications up to 160 ºC. The total technical potential of solar thermal is 9.25 GWt and 7.93 TWh/year of thermal energy generated, with a substantial weight of residential buildings in the total value. Potential values are disaggregated by NUTS III and type of building. In terms of biomass and bioenergy potential, annual values of forest biomass, agricultural biomass, agro-industrial waste, urban waste and wastewater treatment are estimated, totaling around 58 TWh/year. Regarding the production of biofuels (HVO and FAME) it is estimated that the annual production of domestic used oils and other similar residues is 1.4 TWh/year. The use of oils from food crops such as soybean, sunflower and rapeseed is limited by European (and national) policy guidelines and is 2.1 TWh/year. Regarding wave energy, the resource potential is estimated between 1.4 GW for 80 m bathymetry and 4.8 for 20 m bathymetry. There are substantial uncertainties associated with the presented values, inherent to the methodological approach considered. Nevertheless, these estimates are a valuable starting point to be refined and improved in subsequent updates.
- Computational model of a Calcium-looping fluidized bed calcination reactor with imposed concentrated solar irradiancePublication . Rodrigues, Diogo; Rivero, Mayra Alvarez; Pinheiro, Carla I.C.; Cardoso, João P.; Mendes, Luís FilipeABSTRACT: The Calcium-looping process is a promising option for thermochemical energy storage in concentrating solar power plants. A crucial element of this process is the solar calcination reactor, where the endothermic reaction of CaCO3 calcination occurs with formation of CaO and CO2. The solar energy that is chemically stored in the reaction products can be retrieved by the exothermic reaction of CaO carbonation when needed. In this article, a new computational model is developed for the solar calcination reactor in this Calcium-looping process. The calcination reaction takes place in the riser of a continuous circulating fluidized bed that corresponds to an absorber tube exposed to concentrated solar radiation, which allows the reaction chamber to be indirectly heated. A core-annulus heat transfer model and a modified version of the Kunii-Levenspiel fluid dynamics model are used. In contrast to previous models found in the literature, the change in the mass flow rate of the species and in the density of the phases due to the reaction is considered. Simulation studies are performed with a fixed and imposed concentrated solar irradiance on the reactor wall, which varies in both the axial and angular directions. Wall conduction in the angular direction is also considered. The results show that nearly complete calcination can be achieved with a reactor of 4 m of height. A sensitivity analysis with respect to the model parameters and inlet conditions shows that the calcination conversion is mostly affected by the solids mass flow rate and the bed temperature at the inlet.
- Simulação de um sistema de receptor central de pequena potência para fornecimento de electricidade e calor na indústria agroalimentarPublication . Cardoso, João P.; Maag, G.; Bezerra, P.H.S.; Oliveira, C.; Mendes, J. FarinhaRESUMO: Dada a importância económica da indústria agroalimentar e o seu peso no consumo total de energia, é imperativo promover medidas de eficiência energética e introdução de fontes de energia renováveis neste sector por forma a reduzir a sua pegada ambiental e promover o seu desenvolvimento sustentável. Este trabalho foca-se num modelo TRNSYS desenvolvido com o objectivo de estudar a integração da energia produzida por um sistema de receptor central de pequena potência em matadouros brasileiros. É apresentando o modelo e resultados de simulação de uma instalação de demonstração, construída no campus de Pirassununga da Universidade de São Paulo. Este sistema permite fornecer 70 kW de potência eléctrica e 300 kW de potência térmica, suprindo as necessidades energéticas de um matadouro. Simulações de desempenho anual indicam que este sistema solar térmico concentrador permite o fornecimento de 394 MWh de electricidade e entre 190 a 236 MWh de água quente aos processos industriais do matadouro, suprindo a totalidade do consumo eléctrico e entre 96 a 99% das necessidades de energia térmica.
- Estimativa do potencial técnico para secagem de lamas provenientes de ETAR nas regiões do Alentejo, Algarve e AndaluziaPublication . Cardoso, João P.; Mantilla, Victor; Lobo, Gonzalo; Martins, AntónioRESUMO: Os processos de depuração de águas residuais urbanas produzem lamas com um conteudo elevado de humidade que aumenta os custos associados à sua disposição final. A secagem de lamas de depuração tem um valor económico e ecológico, permitindo a redução da massa de material a processar e a consequente redução de custos e emissões carbónicas associadas ao processo de tratamento e deposição final. Este trabalho apresenta uma estimativa do potencial da utilização de energia solar térmica na secagem de lamas produzidas por estações de tratamento de águas residuais localizadas nas regiões do Alentejo e Algarve, em Portugal, e Andaluzia em Espanha, utilizando informação meteorológica pública. A secagem solar de lamas de depuração é viável nas três regiões, estimando-se um potencial anual em termos de massa húmida de lama seca por unidade de área de abertura do campo solar entre 895 kg/m2 a 1 062 kg/m2 no Algarve, 913 kg/m2 a 1 010 kg/m2 no Alentejo e 934 kg/m2 a 1 045 kg/m2 na Andaluzia.
- Towards an alignment of national research programmes and funding for CST technologies in EuropePublication . Cardoso, João P.; Marcelo, Teresa; Jarraud, Nicolas; Dufour, Elena; Papanicolas, Costas N.; Mendes, J. Farinha; Blanco-Gálvez, JuliánABSTRACT: One of the STAGE-STE project work packages aims to develop relations with public bodies relevant to Concentrating Solar Thermal (CST) research, such as national research funding agencies, ministries and other leading decision making bodies, in order to foster coordination and alignment of research programmes and funding at European level. Working groups have been created in eight European countries and concept notes were prepared regarding each group’s position on national CST research and funding programmes and its possible alignment at European scale. General trends and main conclusions drawn from the concept notes are presented, aiming to provide clues and common themes to the development of aligned CST research and funding programmes. Although the National Working Groups present different approaches there are coincident points, thus a common Research and Technological Development agenda for CST can be achieved at European scale. The alignment of CST research funding represents an harder task and will demand the improvement of available funding schemes or the development of a new one. However, there is some convergence regarding the general characteristics of the scheme and the kind of projects to be funded.
- Irradiância solar (global, direta e difusa) – metodologia de controlo de qualidade: aplicação a séries temporais medidas no LES/LNEG, LisboaPublication . Marques, Filipe; Páscoa, Soraia; Carvalho, Maria João; Cardoso, João P.RESUMO: A medida das componentes da radiação solar (global, direta e difusa) é muito importante na caracterização de sistemas solares e seus componentes (ex.: coletores solares) em laboratório. As normas de ensaio definem os requisitos necessários aos equipamentos utilizados para a realização das referidas medidas, mas não definem o controlo de qualidade dos dados. A necessidade de medir não só a componente global da radiação solar no plano do coletor, mas também a radiação direta e difusa, permite ao LES ser também detentor de uma base de dados útil noutras áreas de investigação de sistemas de conversão da radiação solar. Desenvolveu-se a aplicação, SIMONEAPP, que integra um controlo de qualidade seguindo o método QCRADv2. Quando aplicada ao período 2015-2018, permitiu identificar erros de medida de irradiância difusa decorrentes do uso de anel de sombreamento e outros erros de medida da irradiância previamente identificados durante a operação regular da estação meteorológica. No entanto, a metodologia assinalou potenciais erros entre os 2º e os 19º de altitude solar, cuja natureza será ainda necessário investigar.
- Portugal 2020 e a Integração de Energias Renováveis nos EdifíciosPublication . Mendes, J. Farinha; Salgueiro, Andreia; Cardoso, João P.; Coelho, Ricardo EncarnaçãoO elevado consumo de energia nos edifícios tem vindo a ser responsável pela publicação de legislação europeia que visa limitar esse consumo, por via da melhoria dos processos construtivos e da adopção de estratégias de redução do consumo em paralelo com a definição de esquemas de certificação energética que permitam ao mercado escolher e por essa via promover a disseminação das melhores práticas. Em Portugal é o RCCTE, actualmente em processo de revisão, que para além dos requisitos mínimos construtivos obriga a colocação de colectores solares térmicos, mas também valoriza a introdução de outras renováveis nos edifícios. Neste texto iremos percorrer de forma sucinta, as várias tecnologias e aspectos de desenho que já se apresentam no terreno ou se perfilam no horizonte próximo e que em conjunto permitem aproximar de zero, o balanço energético dos edifícios.