An Hourly Building Simulation Model Aimed at Fuel Cell Applications

Abstract

The successful widespread adoption of fuel cell systems is highly dependent upon the economics of the installation. This entails closely matching system capabilities with customer requirements. System sizing requires accurate predictions of building thermal and electrical loads. The TRNSYS-based building simulation model presented in this paper was developed to accurately integrate a fuel cell into the space heating, water heating, and cooling equipment in a building. The simulation tool determines water heating, space heating, and cooling loads for a single zone building on an hour-by-hour basis throughout the year using TMY2 weather data. It integrates empirical and theoretical state point models of the components of a fuel cell-based cogeneration and tri-generation system as well as baseline HVAC technologies. The key components include: hot water loops, stratified water tanks, boilers, furnaces, air conditioners, absorption chillers, space conditioning coils, heat rejection equipment, and ventilation controls. Various control options are incorporated to maintain setpoints, stage equipment, and limit power export. Renewable power systems such as PV and wind are also integrated into the model. The TRNSYS calculation engine iterates to find the state of the system for each hour. The simulation tool also includes post-processing capabilities to apply complex electric tariffs, organize annual simulation results, and manage multiple parametric runs. The tool has been developed to optimize the configuration of a fuel cell in a given building application and to complete numerous parametric runs to evaluate the economics of a system in different locations and building applications. This work was funded in part by the New York State Energy Research and Development Authority.