Exergy–energy analysis for a feasibility trigeneration system at Kocaeli University Umuttepe Campus

Abstract

Abstract In this study, the feasibility of the trigeneration system, which is one of the on-site energy production methods, was determined for Kocaeli University Umuttepe Campus, exergy and energy analyses were made for each point of the system and exergy destruction in the lines was found. The key point of the gains, losses, and efficiency analyses in the lines are presented with engineering solutions and thermodynamic proofs. The seasonal mathematical models covering the whole of the feasibility of the trigeneration system were carried out and the energy and equilibrium equations of the entire system were established. In addition, energy and exergy analysis, 2nd law efficiency, coefficient of performance (COP), and thermal efficiency were calculated for all the systems. The seasonal numerical analyses of the system have been prepared so that it can work effectively in two different working disciplines separately for summer and winter seasons. Thanks to these numerical analyses that are mentioned, the seasonal exergic destructions of the system are found, seasonal working methods are shown, and working conditions and operating load values suitable for the current season are determined. In addition, in the light of the technical studies mentioned above, both the hourly energy capacities and hourly consumption values that the university will produce after trigeneration have been compared by performing separate mathematical models for summer and winter modes. Thus, it has been aimed to reduce the energy production costs by selling the excess energy to the mains. It is for this reason that it is aimed to reduce the energy production costs of the country, to reduce foreign dependency to meet energy demand, to present both a ready to apply feasibility report to investors and a ready to use design of a medium-sized power plant that will set an example of trigeneration studies in academic terms. In today’s practical applications, it is known that the system efficiency of trigeneration systems can be between 70 and 80%. In the light of the studies, 66% exergic efficiency in winter, thermal efficiency of 0.87411 with 2.05 MW thermal capacity, 63% exergic efficiency in summer, COP of 0.82 with 1.5 MW cooling capacity, and 2.02 MWe instantaneous electrical power was found in summer and winter. It was decided that the system could be a facility that is technically open to development and worth establishing in the light of the exergic and energetic analyses results obtained in this study and the exergic system efficiency comparisons made in the literature. In this study, attention was drawn to the importance of exergy and energy analyses in deciding the installation of a trigeneration system, and it was shown that exergic and energetic analyses played a key role in the verification of decision mechanisms. In order to give an idea for other studies in the literature, it is aimed to draw attention to the need to perform seasonal exergy and energy analyses of the designed or desired trigeneration systems.