Model calibration and exergoeconomic optimization with NSGA-II applied to a residential cogeneration

Abstract

New construction buildings should consider high efficiency energy systems according to European Directives. An optimized micro-cogeneration system is an effective solution to improve the energy efficiency of the residential sector. For this reason, this work presents a novel method to model and optimize a micro-cogeneration based on a natural gas internal combustion engine. The facility, which is located in an experimental plant, provides the equivalent domestic hot water and heating demand of three single-family dwellings. The main aim of this work is to optimize the cost and exergy efficiency of the facility. First, the micro-cogeneration is modeled in TRNSYS. Then, Morris sensitivity analysis is used to detect the model variables for a posterior calibration with experimental data. The employed calibration method is a multi-objective optimization of the error functions between simulated and measured data with the NSGA-II algorithm. After the calibration, optimization with NSGA-II is applied again to the control variables of the model to minimize the cost and to improve the exergy efficiency. The optimized performance produces a daily cost reduction of 24.5%, an exergy efficiency improvement of 21% and a gas consumption decrease of 15%. We also demonstrate the importance of addressing the facility inertia in the models to obtain accurate simulation outputs. The novelty of this work is to present a methodology to optimize the exergoeconomic performance of micro-cogeneration systems by model calibration and optimization using multi-objective optimization with genetic algorithms.