ABSTRACT
Zero-export photovoltaic systems are an option to transition to Smart Grids. They decarbonize the sector without affecting third parties. This paper proposes the analysis of a zero-export PVS with a green hydrogen generation and storage system. This configuration is feasible to apply by any self-generation entity; it allows the user to increase their resilience and independence from the electrical network. The technical issue is simplified because the grid supplies no power. The main challenge is finding an economic balance between the savings in electricity billing, proportional to the local electricity rate, and the complete system's investment, operation, and maintenance expenses. This manuscript presents the effects of the power sizing on the efficacy of economic savings in billing (ηSaving) and the effects of the cost reduction on the levelized cost of energy (LCOE) and a discounted payback period (DPP) based on net present value. In addition, this study established an analytical relationship between LCOE and DPP. The designed methodology proposes to size and selects systems to use and store green hydrogen from the zero-export photovoltaic system. The input data in the case study are obtained experimentally from the Autonomous University of the State of Quintana Roo, located on Mexico's southern border. The maximum power of the load is LPmax = 500 kW, and the average power is LPmean = 250 kW; the tariff of the electricity network operator has hourly conditions for a medium voltage demand. A suggested semi-empirical equation allows for determining the efficiency of the fuel cell and electrolyzer as a function of the local operating conditions and the nominal power of the components. The analytical strategy, the energy balance equations, and the identity functions that delimit the operating conditions are detailed to be generalized to other case studies. The results are obtained by a computer code programmed in C++ language. According to our boundary conditions, results show no significant savings generated by the installation of the hydrogen system when the zero-export photovoltaic system Power ≤ LPmax and DPP ≤ 20 years is possible only with LCOE ≤ 0.1 $/kWh. Specifically for the Mexico University case study, zero-export photovoltaic system cost must be less than 310 $/kW, fuel cell cost less than 395 $/kW, and electrolyzer cost less than 460 $/kW.
ABSTRACT
This research analyzes the impact of a hybrid off-grid renewable energy system consisting of wind turbines, solar photovoltaic, hydrokinetic turbines and battery-backed to provide a group of novel airplane-shaped buildings, generates development in nearby towns that sit on a city vantage point from Cuenca in Ecuador. This is an innovative proposal that, in addition to using renewable energy in the complex of buildings, generates development in nearby towns. Three sources of renewable energy under energy control, load cycle and load monitoring are used to determine new patterns in the behavior of the sources with respect to the demand for electricity. Above all, it reduces carbon. With the support of HOMER Pro, the generation sources are optimized to cover the electrical demand patterns of the group of buildings in the form of airplanes. The results show that the systems that include solar panels, wind and hydrokinetic generators have a higher cost but there is more guarantee by maintaining their charge levels in the batteries above 40%. The proposed methodology and design can be widely adapted to places with similar characteristics worldwide, creating a novel solution for this type of buildings powered by renewable energy. The annual energy required by the set of buildings is 234.86 MW h/year. When projecting the renewable energy system for 25 years, an NPC of $37,600 and a COE of $0.386/kWh are achieved.
ABSTRACT
RESUMO As áreas urbanas buscam novas opções de serviço de água, para garantir o abastecimento. A literatura acadêmica versa sobre o pensamento de que a crise hídrica está relacionada ao crescimento urbano; no entanto, o fator predominante é o aumento do consumo, independentemente do crescimento populacional, pois fatores comportamentais devem ser revistos a partir de simples hábitos diários. Os empresários não focam apenas nas questões de economia ou da discussão ambiental, de mais vale a garantia da autonomia, pois a insegurança hídrica é cada vez mais crescente. Empreendimentos como os shopping centers poderão consumir volumes de água equivalentes ao consumo de 5 mil pessoas. Para saber as percepções dos atores envolvidos no design e na gestão de shopping centers, este trabalho utilizou o método AHP, com a aplicação de questionários e resultados combinados. Dados resultantes demonstram que o conhecimento dos envolvidos nem sempre corresponde aos conceitos de conservação de água e que uma melhor sinergia entre a ciência e o mercado deve estar mais próxima.
ABSTRACT Urban areas seek new water service options, to ensure the supply. The academic literature deals with the thought that the water crisis is related to urban growth; however, the predominant factor is the increased consumption, regardless of population growth, as behavioral factors should be reviewed based on simple daily habits. Entrepreneurs do not focus only on economic issues or on top of environmental discussion, as well ensuring autonomy, as water insecurity is increasingly growing. Enterprises such as shopping malls may consume water volumes equivalent to the consumption of 5,000 people. In order to know the perceptions of the actors involved in the design and management of shopping malls, this work used the AHP method, with the application of questionnaires and combined results. Resulting data demonstrate that the knowledge of those involved does not always correspond to the concepts of water conservation and a better synergy between science and the market should be more forthcoming.
ABSTRACT
RESUMO A implantação de sistemas de aproveitamento de águas pluviais (SAAPs) em edificações com alto consumo de água, como estabelecimentos hospitalares, pode trazer benefícios tanto econômicos aos usuários como ambientais. No entanto, é considerada por alguns como a última ação a implementar na conservação da água nessas instituições, recomendando-se, em um primeiro momento, ações de diminuição de consumo. Por isso, este trabalho teve como objetivo avaliar o potencial de economia de água decorrente da implantação de um SAAP como alternativa de abastecimento de água e estabelecer comparações com ações de diminuição de consumo, tendo como objeto de estudo o Hospital Universitário (HU), da Universidade Federal de São Carlos, São Paulo. Para tanto, foi adotada uma metodologia baseada no balanço hídrico em função das demandas de água para diferentes usos no HU e em relação às edificações atualmente em funcionamento e ampliações futuras, previstas em dos fases; análises do tamanho ótimo de armazenamento e avaliação da redução de consumo com um maior controle das perdas e a substituição de tecnologias existentes por dispositivos economizadores nos mesmos períodos. Com a determinação da relação oferta-demanda, a implantação do SAAP evidenciou um potencial de economia de água de 57% do consumo com as instalações atualmente em funcionamento e de 19% do consumo final projetado para o final das ampliações, enquanto as ações de diminuição apontaram valores de 37 a 24% para os mesmos cenários. Procedimentos combinados de aproveitamento de águas de chuva e diminuição de consumo de água podem economizar entre 71% do consumo atual e 39% no final de projeto, níveis considerados significativos e que refletem a necessidade do gerenciamento estratégico da água que promovam benefícios financeiros, ambientais e sociais.
ABSTRACT The implementation of rainwater harvesting systems (RWHS) in buildings with significant water consumption, such as hospitals, can bring both economic and environmental benefits to users. However, it is considered by some the last action to be implemented in the conservation of water in these institutions, recommending at a first moment actions to reduce consumption. That is why the purpose of this study was to evaluate the potential of water saving by means of the implementation of a RWHS as an alternative of water supply and to establish comparisons with water uses conservations actions, having as an object of study the University Hospital of the Federal University of São Carlos - SP (UH). This was determined by a methodology based on the water balance as a function of the water demands for different uses in the UH and in relation to the buildings currently in operation and future extensions, planned in the phases; optimal storage size analysis and consumption reduction assessment with greater loss control and replacement of existing technologies with cost-saving devices over the same periods. With the determination of the supply - demand relationship, RWHS's implementation showed a water saving potential of 57% of the current consumption and 19% of the projected end, while the decreasing actions indicated values of 37 to 24% for the same scenarios. Combined actions for rainwater harvesting and reducing water consumption can save between 71% of current consumption and 39% at the end of the project, which are considered to be significant levels and reflect the needs of strategic water management with financial, environmental and social benefits.