In-field experimental study and multivariable analysis on a PEMFC combined heat and power cogeneration for climate-adaptive buildings with taguchi method

Due to overwhelming advantages in high power density, stability in long-term storage and clear by-product water, application of hydrogen energy in buildings has attracted global interests for sustainable and lowcarbon transformation, especially with the fast technology development of proton exchange membrane fuel cell (PEMFC) combined heat and power (CHP) cogeneration system. However, the cost-effective operating control of PEMFC CHP cogeneration system has not been investigated, comprehensively considering intermittence and stochasticity of building energy demands in different climate regions under extreme climates. In this study, in-field experimental study following the orthogonal method is conducted for underlying mechanism analysis of operating parameters on electric power, total power, and electric/thermal (E/T) power ratio of a PEMFC stack, considering energy losses by convection, radiation and exhausted reactant gas flow. Sensitivity analysis of operating parameters on PEMFC output performances is conducted based on Taguchi Method. For climate-adaptive applications of PEMFC CHP cogeneration systems in Guangzhou (cooling-dominated area) and Beijing (heating-dominated area), two operating strategies with electricity- and heat-dominated outputs have been proposed and compared. Results indicate that, the PEMFC output performances are influenced by internal factors, including reaction rate, substance transportation, membrane hydration level and energy losses. Electric power and total power are mainly dependent on coolant inlet temperature, inlet gas pressure and coolant flux, while E/T power ratio is mainly controlled by inlet coolant temperature, inlet gas pressure and cathode stoichiometric ratio. Furthermore, based on the proposed cost-effective operating control (the electricity-dominated output control strategy under extreme hot weather in Guangzhou and heat-dominated output control strategy under extreme cold weather in Beijing), the PEMFC could save 0.246 kg hydrogen with 2.137 x 103 kJ surplus thermal energy one day in Guangzhou, and save 2.763 kg hydrogen with 3.527 x 103 kJ surplus electric energy one day in Beijing. This study could provide a guideline for operating parameter selections of PEMFC CHP cogeneration system in variable climate areas.