Abstract
Energy consumption and CO_2 emission for the construction and the operation of an environment-oriented office building were calculated and compared with an existing reference office building. Environment-oriented means are use of recycled materials such as electric furnace steel and concrete block, providing balcony for easy contact with nature and atrium for day-light utilization and office amenity. Solar battery, fossil battery and task/ambient lighting system are provided for energy saving. The structure of two buildings have 6 stories with 1 basement floor and the floor area is about 11000m^2, but the building area of environment-oriented office building with atrium is 10% larger than the reference office building. Energy consumption and CO_2 emission for construction are calculated with input/output analysis using the table in 1990. The effective means for construction are use of electric furnace steel, which final production energy is 57.3% of convert furnace steel. Task/ambient lighting system is also effective for operating energy consumption, which electricity load is 57.5% of general ceiling-lighting system. Though the investment of the environment-oriented office building increases 2.9% compared with the reference office building, energy for construction decreases 12.5%, and CO_2 emission, 16.6%. The energy for operation decreases 26.1% and CO_2 emission, 19.8%. Payback period which is a value of increased investment divided by decreased annual operating cost, counts for 5.9 years, so the environment-oriented office building keeps within the bounds of possibility.
