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- Electrical driven pyrolysis reactor retrofit for indirect concentrated solar heatPublication . Azevedo, Pedro; Costa, PaulaABSTRACT: Aiming for a climate-neutral economy, and the associated transition towards fuels produced from alternative feedstock, and to overcome some biomass pyrolysis unsuitable properties for the conventional combustion devices, plastics pyrolysis also produces oils, whose main compounds are also hydrocarbons, that can be used in conventional engines without so complex and costly upgrading processes. Most of the chemical reactions found in a pyrolysis process are endothermal thus, to fulfill that energy demand, the retrofit of a 4 kW electrical furnace pyrolysis reactor to indirect solar driven energy was assessed aiming to adapt it to a central receiver solar tower with up to 100 kWth-peak, using air as heat transfer fluid. The heat demand along a typical pyrolysis test was experimentally assessed and a heat transfer mathematical model was defined to address the working constraints of the reactor. Additional analysis considering new design parameters were performed, namely sensitive analysis to the length of the new heating coil and its overall heat transfer coefficient, the reactor temperature set point, the inlet and outlet (to the atmosphere) gas temperature and working mass flow rates and temperatures were found to provide the same heat demand and minimize the waste heat. Considering both the heat source facility and the reactor constraints, it was found that the retrofit is possible providing that the product of surface area by the overall heat transfer coefficient (A·U) yields more than 17.7 W/K, for a reactor temperature set point of 450 °C and a maximum temperature inlet of 700 °C.
- STTF 100 : Memória descritiva : energia e comunicaçõesPublication . Azevedo, PedroABSTRACT: A Solar Tower Testing Facility – 100 (STTF-100) é uma infra-estrutura experimental que consiste num concentrador solar do tipo sistema de receptor central, também designado por torre solar, e que ocupa uma área total de aproximadamente 725 m2. Esta instalação encontra-se localizada no campus do LNEG em Lisboa.
- Development of advanced characterisation tools for the prediction of reburn performance in PF combustors: 3rd annual reportPublication . Carapau, Nuno; Bent, Raquel; Azevedo, Pedro; Gulyurtlu, Ibrahim; Boavida, Dulce
- Energia e sustentabilidadePublication . Cabrita, Isabel; Azevedo, Pedro; Crujeira, Teresa; Guerreiro, Isabel
- NewSOL Project : Fluent: Case 0Publication . Azevedo, PedroABSTRACT: This document presents all the described steps in order to set up what is called Case 0. In the following work the inlet mass flow and temperature, the heat losses through walls, the materials themselves and their properties, including, porosity and the turbulence and radiative heat transfer models can also be changed. Everything can change, but the mesh. The only exception to this is to refine the mesh a little bit in particular areas in order to increase detail and mitigate some flow problems and improving the results.
- 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.
- NewSOL Project: Thermocline degradationPublication . Azevedo, PedroABSTRACT: According to Task 6.3 of DOA, LNEG was supposed “to define an appropriate monitoring scheme and set of tests to collect the experimental data from the thermocline tank (TCT), necessary to the evaluation of the thermodynamic performance of the prototype and improvement and validation of the computational models”. However, due to known delays on the construction phase of the thermocline tank, the experimental period and its related data is not available, at the moment. Nevertheless, although the validation of the computational models was not possible, some additional adaptions to the models and analysis were developed that can impact namely the assessment of the cycling effect over effective thermal capacity, including for an upscaled solution. This report approaches the problem of the thermocline tank (TCT) degradation that can develop after consecutive cycles. Besides the control strategy, calculations were performed towards the assessment of the prototype TCT performance considering the control scheme disclosed in D7.91 and in some literature2. An alternate operation strategy is proposed, and its performance assessed and, finally, an upscaled TCT, also disclosed in D7.9, is also assessed considering the alternate operation strategy.
- Reduced mechanism for combustion of hydrogen and methane with nitrogen chemistryPublication . Azevedo, Pedro; Cabrita, Isabel; Pinho, C.A reduced chemical kinetic reaction mechanism that could be used in computational fluid dynamics (CFD) software was developed to describe the formation of nitrogen oxides and their subsequent destruction in hydrogen and/or hydrocarbon flames with or without seeding of nitrogen compounds. The research work presented here will describe the numerical work done with the application "CHEMKIN" in order to verify the quality of the reduced mechanism. The mechanism was validated through comparisons between computational data from a variety of different sources. In addition, numerical experiments were carried out to examine features of methane combustion in which the detailed mechanisms can be used to compare their response. The proposed reduced mechanism provides reasonable agreement with the studied detailed mechanisms, mainly in the species produced from the hydrocarbon oxidation process. Regarding the produced nitrogen species, the proposed reduced mechanism showed the same tendencies as the detailed mechanisms, but there is a need for a better agreement regarding the quantities.
- Estudo experimental e numérico de um queimador de gás naturalPublication . Azevedo, PedroNeste trabalho pretendeu-se demonstrar a aplicabilidade da modelação de dinâmica de fluidos através de um código computacional (Fluent/UNS), para a previsão de escoamentos de fluidos e respectiva combustão, numa fornalha horizontal. Foi introduzido o gás natural como combustível, através da utilização de uma mistura com características idênticas à do gás natural. Foram realizados ensaios cromatográficos ao combustível para verificação da composição elementar. Para a construção da malha computacional utilizada no modelo numérico, tornou-se necessária a utilização de dois programas, por forma a permitir a integração dos 37 injectores, respeitantes ao queimador, na face da fornalha. Foi escolhida uma malha com cerca de 78000 células, que garante a indepedência dos resultados. Para modelação do escoamentofoi utilizado o modelo de turbulência k-ε, por se adequar melhor ao escoamento em causa, bem como pelas exigências computacionais. A transferência de calor por radiação no interior da fornalha, é calculada através da utilização do Modelo de Radação de Transferência Discreta (DTRM). Os resultados numéricos foram validados por ensaios experimentais, realizados com um queimador protótipo montado numa fornalha horizontal, cujos resultados foram analisados juntamente com os homólogos numéricos.
- INIESC : infraestrutura nacional de investigação em energia solar de concentraçãoPublication . Horta, Pedro; Canavarro, Diogo; Azevedo, PedroRESUMO: A INIESC, Infraestrutura Nacional de Investigação em Energia Solar de Concentração, parte integrante do Roteiro Nacional de Infraestruturas de Investigação, apresenta-se como a infraestrutura experimental de referência, em Portugal, no domínio das tecnologias e aplicações da energia solar a média e alta temperatura. Liderada pela Universidade de Évora e desenvolvida em parceria com o Laboratório Nacional de Energia e Geologia, I.P., a infraestrutura conta com dois pólos: Évora e Lisboa. Visando investigação que promove uma potenciação do contributo da energia solar na descarbonização de diferentes sectores da economia – geração eléctrica, transportes, gestão do sistema energético, comunidades energeticamente independentes, processos industriais – as actividades da INIESC abarcam tópicos que incluem, e.g., o desenvolvimento de tecnologias de colectores, o armazenamento de energia, a produção de combustíveis por via solar e a durabilidade de materiais. Neste artigo apresenta-se o estado actual de desenvolvimento da infraestrutura, assim como um resumo das actividades de I&D nela desenvolvidas até ao presente.
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