LEED BD+C: Core and Shell v3 - LEED 2009
Nippon Life Marunouchi Garden Tower
LEED Gold 2015
The Nippon Life Marunouchi Garden Tower is an office building for lease with a floor area of 56,120 gsm (604,071sf), height of 115m (377ft), and 22 stories located in the heart of the Marunouchi central business district in Tokyo, where occupants can enjoy stunning views to the Imperial Palace Garden and the Wadakura Fountain Garden.
The owner, Nippon Life, has continuously strived to create environment-friendly office buildings as a developer. As the Marunouchi district is an area where many multinational companies locate their Japanese branch offices, Nippon Life’s intent for this building is to express sustainability in a measurable and comprehensive way using the internationally acknowledged LEED rating system to meet the potential needs of international lessees.
The adopted environmental features in Nippon Life Marunochi Garden Tower are realistic in economic and operational aspects for an urban high-rise office building. The first feature is the classical looking façade consisting of architectural sunshades and coupled exterior columns. The architectural sunshades shelter the windows and adjust natural lighting while coupled exterior columns maximize views. The exterior columns also allowed maximizing the leasable area, approximately 1,688sm (18,169sf) per floor, designed to be a column-less open space so that it is reconfigurable with less construction.
The second feature is the hybrid VRF heat pump and desiccant system, compact outdoor air treatment equipment concealed in plenum. By separating outdoor air treatment unit dedicated for treating latent heat, and separate VRF systems for treating indoor sensible heat loads, the system can be operated at higher temperature setpoint, providing a significant improvement in system energy efficiency. In fact, the greatest challenge in achieving LEED certification was to model this Japanese unique innovative technology in simulation software. The calculated total energy cost saving was 28%.
The third feature is the use of recycled steel. High-rise office buildings in urban areas are generally steel structure, as is this building. Maximum use of recycled steel for structure largely contributes to the overall percentage of recycled material use in the project.
The fourth feature is water reuse. Kitchen wastewater from food service tenants on the lower floor and other sanitary wastewater are treated and reused for toilet flushing. Harvested rainwater is reused for irrigation.
As mentioned, the Nippon Life Marunouchi Garden Tower is a showcase of an urban high-rise office building that has overcome the physical and economic restrictions and fructified as the first LEED-CS certified building in Marunouchi area.