Simulation of design and operation of hydrogen energy utilization system for a zero emission building

Nearly 40% of the total greenhouse gases (GHGs) are emitted from the energy consumption in buildings in Japan, which should be reduced to address global warming. A hydrogen energy utilization system with renewable energy (RE) was designed by MATLAB/Simulink simulations for realizing a zero emission building (ZEB), comprising a hydrogen-producing electrolyzer, a hydrogen storage tank, fuel cell, and battery for short-term power storage with estimated specifications of 3.0 Nm3/h, 36 Nm3, 4.2 kW, and 10 kW/17 kWh, respectively. We identified a small low-rise building (total floor area: ∼1000 m2, demand: ∼5 kW) as the planned ZEB to construct and operate a bench-scale system. A 20-kW photovoltaic (PV) system was selected as the RE source. Two hydrogen production processes (constant power of 10 kW or with excess PV power) were evaluated by simulating 48-h operations on fine and cloudy days, where the former showed higher efficiency. The results with excess power on a fine day agreed well with that of actual operation, validating our simulation models. Further, the constant case was suitable for practical application.