Energy and exergy efficiency of a building internal combustion engine trigeneration system under two different operational strategies

摘要

Trigeneration systems can be a good choice for distributed power production in buildings with coincident energy demands. Demand in a building can vary with the hour of day, activity, occupancy and climate, and can fluctuate widely. Trigeneration systems will achieve a high energy utilization factor (EUF) at hours when the degree of coincidence is high, but a lower EUF when coincidence is low. In order to improve performance, energy of the prime mover should be compared with site energy demands. Simulation can contribute to improving design of cogeneration systems. This paper presents a computational hourly profile simulation methodology that combines into a single algorithm curve fittings from the literature and manufacturer data, mathematical representations of physical phenomena, and thermodynamic properties. This simulation methodology was used to predict the performance of a given cogeneration concept under two different operational strategies. Performance evaluation was based on EUF, exergy efficiency and primary energy savings (PES) analysis. Results obtained in the case study revealed an EUF between 65 and 81%, and an exergy efficiency between 35 and 38.4%. The PES analysis showed that the proposed cogeneration system can compete with high-efficiency thermal plants.