This study aims to evaluate the stable operation of buildings, life cycle cost, and whole-life carbon in a community where hydrogen is transported from production sites to end-use points. For this purpose, a small-scale test facility was constructed at the Okinawa Institute of Science and Technology (OIST), located in southern Japan, and demonstration experiments were initiated.
The facility consists of a trailer house, representing a residential building, and a hydrogen storage unit capable of accommodating 18 high-pressure hydrogen cartridges, each with a charging pressure of 29.4 MPa and a volume of 6.8 L. The trailer house is equipped with household appliances such as an air conditioner, a continuously operating type-III ventilation fan, and a refrigerator, thereby reproducing realistic residential power demand. The energy supply system comprises photovoltaic (PV) panels, a battery storage unit, and a pure hydrogen fuel cell, with the operational priority defined as (1) PV, (2) battery, and (3) hydrogen fuel cell. Six hydrogen cartridges are connected to the fuel cell, which operates only when the PV and battery cannot meet the load, consuming hydrogen sequentially from the cartridges. Before all six cartridges are depleted, fully charged cartridges are transported from the storage unit to the trailer house using an electric vehicle (EV) cart.
To verify the effectiveness of this system, a demonstration test was conducted during a summer period, clarifying the actual utilization of solar and hydrogen energy. The results demonstrate that the combined use of renewable energy and hydrogen energy at a residential scale can contribute to stable energy supply and sustainable building operation.