Effect of the Power Generation Unit Operation on the Energy, Economical, and Environmental Performance of CCHP Systems for a Small Commercial Building

Combined cooling, heating, and power (CCHP) systems generate electricity at or near the place of consumption and utilize the accompanying waste heat to satisfy the building’s thermal demand. CCHP systems have often been cited as advantageous alternatives to traditional methods of power generation and one of the critical components affecting their performance is the power generation unit (PGU). This investigation examines the effect of the PGU on the energy, economical, and environmental performance of CCHP systems. Different size PGUs are simulated under the following operational strategies: follow the building’s electric load, follow the building’s thermal load, and operate at constant load. An internal combustion engine is used as the PGU in the CCHP system to meet hourly electric, cooling, heating, and hot water loads of a typical office building for a year. Annual operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE) are found for two cities and compared to a conventional building. Finally, a simple optimization is performed to determine the best engine load for each hour during the simulation. Among the results, the smallest engine generally yielded the lowest costs and lowest PEC; but, no such trend was found with regards to CDE.