Energy-exergy-emergy optimization analysis designed for combined cooling and power systems driven by proton-exchange membrane fuel cell

The rapid increase in energy consumption by data centers has underscored the necessity for energy conservation. Hence, this study proposes two proton-exchange membrane fuel cell (FC)-driven combined cooling and power (CCP) systems, i.e., a CCP system with a fluorine pump natural-cooling device (CCP-FC/FP) and a CCP system with a solar thermal device (CCP-FC/ST). The performances of both systems are evaluated by considering thermodynamic indicators and emergy analysis. Because conventional thermodynamic evaluations cannot differentiate between renewable and nonrenewable resources, emergy analysis may result in calculation bias; thus, a novel energy-exergy-emergy evaluation system that integrates thermodynamic evaluation indices with emergy analysis is introduced. Furthermore, a high-dimensional multi-objective optimization is performed on the two combined cooling and power systems, where the newly proposed evaluation system is used as the optimization target. Results indicate that the proposed systems offered higher energy efficiency, reduced environmental effects, and enhanced the cooling capabilities compared with conventional CCP systems. The impacts of the main operation parameters on energy-exergy-emergy indicators are discussed in detail. For the optimized CCP-FC/FP system, the energy-utilization and exergy efficiencies increased by 2.94 % and 2.97 %, respectively. For the optimized CCP-FC/ST system, emergy investment ratio decreases by 9.56 %, whereas its emergy sustainability index increases by 12.39 %.