Performance investigation of a net-zero energy building in hot summer and cold winter zone

The net-zero energy building (NZEB) is spreading rapidly as an integrated solution to address energy saving and carbon emissions reduction in the building sector. However, few studies pay close attention to the operational performance of NZEBs as well as their life cycle impact on the environment. This study investigates the operational performance of NZEBs, analyzes the influence factors in achieving net-zero energy, and explores the pathway to reduce the building life cycle carbon emission via a case study conducted from March 2017 to February 2018 in the hot summer and cold winter climate zone of China. The one-year investigation results show that the case building, where energy-efficient technologies and renewable energy were integrated, achieved net-zero energy with good indoor environmental quality. Based on the investigation, influence factors in achieving net-zero energy were analyzed via DesignBuilder: the minimum area per capita was 42 m(2)/person under the circumstance of net-zero energy; when operational strategy was changed, the air-conditioning energy use reduction was less than 5%. Additionally, in order to achieve net-zero energy, an equation was proposed to estimate the area ratio of installed photovoltaic (PV) panels to that of the building roof, thereby providing guidance for NZEBs design. Furthermore, life cycle carbon emissions of the project were evaluated. Based on the foregoing results, it can be concluded that by increasing carbon offsets of the PV system appropriately, an NZEB can be transformed into a life-cycle zero-emission building. Moreover, it is necessary to mention that the life cycle carbon emissions of the PV system should be considered.