Special Feature1 : Promotion of next generation researchand development "The Urban ZEB®"

The Urban ZEB
Miyoshi Kato

Deputy General Manager,
Design Division
Miyoshi Kato

Buildings That Consume Huge Amounts of Energy are Located in Urban Areas

As energy problems and global warming problems intensify due to increasing CO2 emissions, Taisei Corporation is aiming to achieve the Urban ZEB. A ZEB (net Zero Energy Building) is a building that significantly reduces energy consumption, while at the same time accepting renewable energy such as generating solar energy, to bring the net annual energy consumption to Zero.
Conventional energy conservation buildings are those that utilize technologies for conserving energy in various places to curb energy consumption as much as possible. On the other hand, ZEB is taking it a further step forward and aims for Zero annual net energy consumption for the entire building by using energy conservation + power generation.
Energy consumption in Japan is concentrated in urban areas with high population densities.
As a company involved in construction, we have chosen as our mission contributing to solving global environmental issues by pursuing Urban ZEB, which is rare even worldwide.

Zero Energy is Achieved Within a Standalone Building

The salient feature of Urban ZEB is the aim of achieving net zero annual energy within a standalone building.
The definition of ZEB varies globally. The shortfall of energy generation from a standalone building is mostly compensated for by such as factors solar energy generation that is separately installed on the site. However, for urban office buildings, as there is no space to install a lot of equipment for generating energy onsite, there is a need to promote ZEB for standalone buildings. Since there is a limit to the energy that can be generated, it is important to accelerate thorough energy conservation.
As a first step in tackling the challenge of this most difficult issue, a ZEB demonstration building was constructed on the site of Taisei Technology Center.
In the ZEB demonstration building, by advancing effective combinations of technologies and the development of new technologies as well as carrying out detailed simulations taking into account changes of seasons and the weather, significant energy conservation was achieved. It aimed to reduce annual energy consumption by 75% in comparison with typical office buildings and to cover the remaining 25% by generating energy.
Operations began in June 2014. The monitoring results and verifications led by researchers at the Technology Center showed that through energy conservation, the energy consumption was 463MJ/m² per year while at the same time energy generation was 493MJ/m² per year, which means that a standalone building could achieve net zero annual energy consumption as the simulation predicted. Overcoming this extremely difficult obstacle enabled us to complete preparations to introduce ZEB anywhere within Japan.

ZEB demonstration building, Taisei Technology Center

ZEB demonstration building constructed at the site of the Taisei Technology Center. The building contains three floors above ground with a floor area of 1,277.32 m², which is a configuration applicable to medium scale office buildings in urban areas. While conducting regular business, research workers are also evaluating the comfort of the office building as an environment for conserving energy. (Ministry of the Environment "Low Carbon Technology Research and Development Program")

Energy Consumption and Population are Concentrated in Urban Areas

In Japan, 49% of the population is concentrated in major urban areas such as Tokyo, Osaka, Nagoya, which also consumes 48% of domestic electricity while only occupying 5% of the land area. Taisei Corporation considers that reducing energy consumption in urban areas is more efficient in reducing the environmental load and so is accelerating the popularization of Urban ZEB.

* Reference materials
Area and population: "Chronological scientific tables" compiled by the National Astronomical Observatory of Japan Quantity of electricity: The Japan Electric Association "Handbook of Energy & Economic Statistics"

The Emphasis is not only on Zero Energy but Also Considering Safety and Comfort

Taisei Corporation's Urban ZEB stresses the balance of safety and comfort.
It uses short-stroke seismic isolation system that makes maximum use of a limited site with the installation of switching dampers. This ensures the building's safety and supports the business continuity while securing an energy source.
A comfortable office environment is maintained for everyone in the building by utilizing a control system for lighting, heating and cooling that makes use of human detective sensors while considering energy conservation. Approximately 4,600 visitors from both Japan and overseas have visited the ZEB demonstration building since operations started in June 2014. In addition, there have been more than 110 articles published in newspapers and magazines, which shows a high level of interest in Urban ZEB, which is groundbreaking in Japan.

T-ZEB Simulator Completed! It's Possible
to Propose ZEB Solutions Anywhere.

Developing the T-ZEB Simulator

The T-ZEB simulator is a brand new planning and assessment tool developed specifically for the ZEB project. It features revolutionary planning technology that uses observed data to generate fast and accurate ZEB planning assessments and net annual energy consumption reports. The T-ZEB simulator is able to analyze net energy consumption in a variety of scenarios, based on the total energy generated from solar, wind, ground thermal energy, and other sources, taking into account the impact of factors such as site conditions and surrounding structures, and the total estimated energy consumption using a variety of different energy-saving techniques.
The T-ZEB simulator can be used to assess the potential for upgrading building designs to ZEB specifications, and to develop optimized proposals for structures that are not deemed suitable for the full ZEB upgrade.
This tool makes it possible to provide highly accurate proposals in a short period of time by adding detailed data obtained from demonstrations to the simulation values used in the design stage of the ZEB demonstration building. How much energy consumption can be reduced for the entire building?
By educating more people about the merits of ZEB, Taisei Corporation will contribute to the acceleration of ZEB, which can be a powerful trump card in fighting global warming and developing energy conservation.

External evaluation

Building and Environmental Performance

U.S. Green Building Council


U.S. Leadership in Energy & Environmental Design

Energy Conservation Performance

Ministry of Land, Infrastructure, Transport and Tourism


Building Energy-efficiency Labeling System


Ministry of the Environment

2014 Environment Minister's Award for Global Warming Prevention Activity

Introduction and Practice of Climate-friendly Technologies

Open the Way to The Future of ZEB through Continuously Striving for Technological Developments and Innovations

Kazuyuki Shimamura

Executive Fellow Deputy
General Manager,
Environment Division
Kazuyuki Shimamura,

Address Technology Developments and Innovation to Carry the Vision of the Next Generation

The reason why Taisei Corporation decided to start the extremely difficult Urban ZEB is because of the technologies we have developed and accumulated.
Taisei Corporation has promoted the design of office buildings where improvement of environmental performance has been thoroughly carried out throughout the sequence of design, construction, and operation, as in the Taisei Super Eco Building. Amongst those, the Taisei Sapporo Building-completed in 2006 (Taisei Corporation branch office building)-was ranked S (highest rank) for CASBEE.
Additionally, in this building, improvements to operations that were implemented in 2010 enabled a 52% reduction in energy consumption not yet achieved by other companies, which positioned it as the first Half Energy Building in Japan.
Also, in 2007, the main research building of the Taisei Technology Center was renovated as a model for the next generation energy conservation research facility. In 2011, it achieved a reduction of energy consumption by 35% which was the highest level in the renovation field. These approaches have been highly rated, as can be seen in various awards relating to energy conservation.

Taking the Lead in Achieving ZEB in the Development of Next-generation Technologies

ZEB demonstration building utilizes the development of evolved technologies for conserving energy such as radiant heating and cooling, personal heating and cooling and natural lighting system, which were used in Taisei Sapporo Building and the main research building of the Taisei Technology Center. Combining these technologies with newly developed technologies made it possible to achieve outstanding energy conservation performance.
An ambitious goal of reducing energy consumption by 75% was set on the basis of such accumulated technologies.

In Japan, the Strategic Energy Plan decided by the Cabinet in April 2014 indicated that "GOJ aims to achieve net zero energy with regard to a newly constructed public building by 2020 and with regard to all newly constructed buildings on average by 2030." In general, the United States and the EU also set 2020 and 2030 as target years and are moving ahead with approaches to ZEB. In accordance with the national ZEB roadmap, Taisei Corporation is in the process of developing a fully viable ZEB to be ready for launch by 2020.
We will continue taking on the challenge of developing technology and making innovations to carry the vision of the next generation and will lead the charge for achieving Urban ZEB.

Roadmap for Promoting ZEB
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