Integrating green hydrogen into building-distributed multi-energy systems with water recirculation

• Novel water electrolyser and fuel cell integration system for building application. • Proposed system enables water recirculation between the electrolyser and fuel cell. • System designed for a two-story residential building located in Aberdeen, UK. • Both summer day and winter day was analysed to ensure 100 % water re-circulation. This study proposes integrating a building-distributed multi-energy system (BDMES) with green hydrogen to decarbonise electricity generation for buildings. By producing and consuming green hydrogen locally at the building site, using a water electrolyser and proton exchange membrane fuel cell (PEMFC), the reliance on costly, energy and carbon-intensive hydrogen transportation is eliminated. This integration presents an opportunity for energy autonomy, achieved by locally green hydrogen production, storage, and usage. More importantly, the proposed system enables water recirculation between the electrolyser and PEMFC, an effective option worldwide to conserve water resources, and reduce environmental impact. Models are developed to investigate the interaction mechanisms among the photovoltaic (PV) module, water electrolyser, fuel cell, and cooling system. Case study results for a residential building in Aberdeen, UK are presented and discussed, maximum 75 solar panels can be installed on the 150m 2 roof area. Since less solar energy can be harvested in this area, in the peak hour of one summer day, 11 solar panels are required to meet 100 % daily maximum building energy demand and ensure 100 % water recirculation. In one winter-day, total 75 solar panels can only meet 26 % of total building energy demand.