Development of practical empirically and statistically-based equations for predicting the temperature characteristics of PEMFC applied in the CCHP system

In this study, we investigate the temperature characteristics of a proton exchange mem-brane fuel cell (PEMFC) stack applied to a combined cooling, heating and power (CCHP) system for achieve a suitable operating temperature range of PEMFCs and meeting the requirements associated with the heat source temperature of the CCHP system. The functional relationships between the current density, cooling water flow rate, number of single cells, PEMFC temperature, and the cooling water outlet temperature in stacks composed of 5-30 single cells are analyzed. There is a current density interval for each cooling water flow rate that meets the requirements of both the PEMFC and cooling water outlet temperature, which decreases with an increase in the cooling water flow rate. The coefficients of determination (R2) of the equations are all greater than 0.997. The reliability of the equations is verified on a stack composed of 50 single cells, and the error between the predicted and actual results is less than 0.5%. Based on empirical equations, the rec-ommended cooling water flow rate interval is obtained at each current density, and the recommended operating current density should be less than or equal to 1.1 A center dot m 2. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.