| Energy Saving | Case Study Index |

Life cycle energy savings in office building: The Tokyo Gas Kohoku NT Building, completed in March 1996, was built on the basic concept of life cycle energy saving. This concept aims at minimizing overall environmental loads throughout the entire lifespan of the building, from construction to demolition. In planning and designing the building, three principal targets were established. These targets comprised the saving of energy and resources, the extension of the building's service life, and the improvement of amenities.    Basic data: Location: Yokohama, Japan Major function: Office, Showroom Architect: Nikken Sekkei ( in associate with Tokyo Gas Urban Development Co., Ltd at construction administration stage)  Total Floor space: 5,645 m2 No. of storey: 4 storeies above ground and 1 underground Structure: Reinforced concrete, steel structure Overview: Exterior: gasex1.jpg 36.06 Kb  gasex2.jpg 46.52 Kb gasex3.jpg 23.16 Kb  gasex4.jpg 17.37 Kb  gasex5.jpg 54.81 Kb  Interior: gasin1.jpg 90.55 Kb  gasin2.jpg 78.83 Kb  gasin3.jpg 33.30 Kb  gasin4.jpg 43.13 Kb  gas-s3.jpg 130 Kb   Section: A - Custom-designed low-e double glazing B - Light shelf ( Eaves ) C - Automatic ventilation windows ( Fanlight ) D - Gas engine cogeneration system E - Waste heat input type gas-fired absorption    chiller-heater F - Water reclaiming equipment G - Upper deck for equipment and machinery H - Columnless office space I - Ecological core ( Atrium ) J - Rainwater penetration K - Ventilation tower L - Light reflection ceiling ( Sloping ceiling ) Site features This industrial building, Earth Port, operates as a branch office of Tokyo Gas Company. Its design is unique in its mutipurpose functions and energy-conserving systems. As the service headquarters of a major natural gas company, it was built primarily to deliver maintenance programmes to surrounding consumers and market gas appliances. It also provides many community programmes such as nutrition and cooking classes. The building incorporates a showroom, offices, demonstration kitchens and adaptable spaces designated as teaching and/or meeting rooms. Discrete areas of the facilities are selectively programmed to preserve energy by shutting down the heating and lighting when certain staff are out on service calls. Design features The office space ( H ) is located on three 15-metre deep floors.  The site is restricted, so supporting facilities and car parking are accommodated in a two-level semi-sunken plinth to the building.  Key to the energy strategy is the concept of an "ecological core"  ( I ) incorporating a north-facing atrium along the building's length.  This is used for primary circulation and for display of the company's products. The offices themselves are separated from the atrium by a walkway and a three-quarter height semi-translucent glazed screen. Daylight reaches the office space either via the atrium or from the ribbon glazing on the south side.  External horizontal sun breakers also act as daylight shelves ( B ); these are located about 1.25 m from the head of the window.  The opening lights are situated above the sun breakers and incorporate diffuse glazing to reduce the effects of glare. The upper light of the window is partially protected from solar heat gain by extending the floor slab about 600 mm beyond the facade.  This projection is also used for window cleaning.  The ceilings of the offices slope slightly towards the center of the office space to maximize the effect of the daylight ( L ). The atrium glazing  ( A ) is supported by giant curved laminated timber beams.  The glazing comprises fixed sealed units with a low-emissivity outer skin.  No solar control has been provided, unusual for this type of building, as it faces north.   From symbiotic Model to Architectural concept The Tokyo gas company's conservation policies strongly promote safeguards for the environment, a comprehensive programme that has won them many awards. Earth Port's design evolved from a 'life-cycle energy-saving' plan based on a joint two-year research project with the architects of Nikken Sekki. The result was a building model of light, airflow and human interaction, and the creation of an "ecological core', an atrium with specific light and air attributes located along the building's length. The researchers surveyed the human use of space and how energy was allocated in modern Japanese architecture. Not surprisingly, it revealed that in modern buildings lighting and air conditioning accounted for approximately 80% of total energy consumption. Based on their findings, the study team targeted air conditioning, lighting and conveyance technologies as areas for major reductions in energy consumption.   Reference: FACT - Nikken Sekkei  Brochure from Nikken Sekkei  Sustainable Architecture in Japan 2000 Building Future Japan 1900-2000 | Energy Saving | Case Study Index | | Created: 13 Aug 2001 | Update: 16Aug2001 | By: cmhui@hku.hk |