ZEB Zero Energy Building
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ZWB Zero Water Building

As the green architecture timeline shown at the top indicates, energy consumption trend found in those awarded projects for The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan Award in recent years reveals a gradual decrease in energy consumption target of office environment from 2,000 MJ/m2 to 1,000 MJ/m2 during the last 20 years.
Not only Japan, but also in the United States, the United Kingdom and other countries set up ambitious realization targets of ZEB for the timeframe from 2020 to 2030. It is necessary to further promote energy saving, and how we should introduce renewable energy use.
It will be asked for ZEB not to get radicalized of its idea and theme by relying solely on technology and theories, but to provide an architectural environment for occupants to live in a healthy, comfortable and rich lifestyle. Green architecture has been developed in diverse directions in active or passive methods, or in combination of both, while either method suggests ingenious application of natural principles utilizing light, wind, greenery, or evaporation and shielding. As shown in the above example figure, smartly designed architectures bring in natural environment into architectural environment, along with external blinds and biological skins to bring in natural light while blocking solar radiation heat, glass-piped louvers to bring in light beautifully, the facade highly integrating exterior wall with green wall system, a bee garden inside the building, and spiral staircase named “ecological cylinder,” in which curves found in nature are applied. ZEB is truly transforming its way into a style called biophilic design oriented toward integration of architecture with living organism and nature.

SDGs are widely known in Japan nowadays as universal sustainable development goals defined by the United Nation to integrate economic, society and, environmental development. One of the 17 goals for hygienic and safe lifestyle is to make “clean water and sanitation” available throughout the world. Effective usage of water resources has now become a global trend. For realizing this goal, it is important not only to deal with water saving and water recycling at a building level, but also to consider water cycle beyond the building site level such as returning rainwater via water permeation into the ground.
Throughout the countries in the world, various developments for the effective usage of water resource has been in progress mainly around drought area where the value of water is high. Shown here are the actual examples of advanced water utilization; for example, an office building which collects water sprinkled for evaporative cooling and reuses it for radiative cooling inside of its interior space, and a water reclaiming system, “sewer mining,” which considers sewer as the “mineral vein” for water resource and bring back sewage water into the building for recycled usage.
In this article, ZEB and ZWB is mentioned not only to suggest synergistic effect of energy saving and water saving, but also as an integral element composing green architecture, contributing to the realization of the healthy living environment integrated with nature.

These ideas originated with "ID200", an activity where about our 200 engineers from the Building Services Design Division propose suggestions each year.