A middle-sized office building (floor area : 5,645 m2), nicknamed “Earth Port,” was renovated with the intention of making it a ZEB (“net-zero energy building”) by 2030. As a first step, the following technologies were introduced. (1) Thermal network utilizing both solar heat and waste heat from gas cogeneration system (CGS) and gas engine driven heat pump (GHP) (2) Bright-feeling lighting system and other measures to utilize natural sunlight (3) Integrated power management system The thermal and lighting environments were measured and analyzed to investigate the indoor environment as well as detailed energy consumption data. Questionnaires for occupants were also conducted to know self-estimated productivity. The renovation resulted in a 37% reduction of primary energy consumption and a 45% reduction of CO2 emissions compared with the average for tenant-occupied office buildings (baseline)
