<b>Techno-economic and Exergoeconomic Analysis of a micro cogeneration system for a residential use

Abstract

ABSTRACT. The aim of the study is to present an economic analysis of a micro cogeneration system using financial analysis (energy view) and exergoeconomic analysis (exergy view). This system uses a natural gas-fueled 30 kW microturbine to generate electricity, and to produce hot water by recovering energy from the waste heat in the exhaust gases by using a heat exchanger, which serves as the drive source of an absorption chiller with a nominal capacity of 35 kW. In the financial analysis economic indicators such as payback, net present value and internal rate of return were used to verify the economic feasibility of this system, while in the exergoeconomic analysis, the Theory of Exergetic Cost was used to determine the exergetic monetary costs. A thermodynamic model was developed on the EES-32 (Engineering Equation Solver) platform. On applying the financial analysis, the results showed that the micro cogeneration system is feasible with positive values of R$ 206,540.00 for NPV, 27% IRR and a 6-year payback. Based on the exergoeconomic analysis, the cogeneration system is also feasible since the monetary cost of the electricity is lower than that charged by the electricity company but this is only possible after the 5 th year.Keywords: net present value, IRR, payback, exergetic costs.Análise Tecno-econômica e Exergoeconomica de um sistema de microcogeração de para uso residencial RESUMO. Este trabalho tem como finalidade o estudo econômico de um sistema de microcogeração de energia utilizando a análise financeira (visão energética) e a análise exergoeconômica (visão exergética). Este sistema utiliza gás natural como combustível primário para o acionamento de uma microturbina de 30 kW para produzir eletricidade, e água quente pelo do reaproveitamento da energia do calor residual dos gases de escape por meio de um recuperador de calor, que serve como fonte de acionamento de um chiller de absorção de 35 kW de capacidade nominal. Na análise financeira foram utilizados os indicadores econômicos tais como: o payback, o valor presente liquido, e a taxa interna de retorno, para verificar a viabilidade econômica do sistema de microcogeração, enquanto na análise exergoeconômica, foi considerada a teoria de custos exergéticos para a determinação dos custos monetários exergéticos. Foi desenvolvido um modelo termodinâmico na plataforma EES-32 (Engineering Equation Solver). Da aplicação da análise financeira os resultados mostraram que o sistema de microcogeração é viável com valores positivos de R$ 206.540,00 de VPL, 27% de TIR, 6 anos de retorno do capital. A partir da análise exergoeconômica, o sistema de cogeração também mostrou-se viável já que o custo monetário da eletricidade é menor do fornecido pela companhia de eletricidade, mas isso é possível após o 5º ano.Palavras-chave: valor presente liquido, TIR, payback, custos exergéticos.

Absorption Refrigeration Systems Based on Ammonia as Refrigerant Using Different Absorbents: Review and Applications

“…The search for systems with better thermal performance, not only of the fluid used, but with the modification of the cycle through the introduction of a component has been done, as shown by Zacarías et al [77] with the addition of several absorbers, or with the use of more compact exchangers [26,27,76,88] or by the integration of ejectors into the system [84], or simply through joining refrigeration systems by vapor compression and absorption [80,89], integration of cycles in the production of electricity and cold [136], and obviously in the use of these ARS in energy polygeneration plants, analyzed and verified technically and financially [67,137].…”

Exergoeconomic Assessment of a Compact Electricity-Cooling Cogeneration Unit

“…Concerning the depletion of fossil fuels and the consequent uncertainties regarding the security of supply, the development and analysis of combined cooling and power systems has been attracting increasing interest in recent years [100][101][102]. The overarching purpose of combined cycles is the improvement of overall energy conversion efficiency in comparison with separate production.…”

Thermoeconomic analysis of a microcogeneration system using the theory of exergetic cost

“…There is a deep relationship between irreversibilities, cost, and cause, to the point that Valero [4] highlighted an Aristotelic analogy between thermoeconomic concepts and cause. Because TEC considers exergy destruction and carries out calculations from this viewpoint, the actual production cost is not separate from the cost of its exergy destruction [5]. Thermoeconomics has been used to check the viability of thermal energy systems [6] and even as an optimization technique to improve the overall energy system [7], taking into account exergy and monetary costs [8].…”