Taking on the ZEB (Net Zero Energy Building) Challenge

Achieving Net Zero Energy Buildings (ZEB) Through Sustainable Renovation
Global Zero Emission Research Center (GZR), National Institute of Advanced Industrial Science and Technology (AIST) September 15, 2021

Achieving Net Zero Energy Buildings(ZEB)Through Sustainable Renovation Global Zero Emission Research Center(GZR),  National Institute of Advanced Industrial Science and Technology(AIST)

Taking on the ZEB Challenge Achieving Net Zero Energy Buildings(ZEB)Through Sustainable Renovation Global Zero Emission Research Center(GZR), National Institute of Advanced Industrial Science and Technology(AIST) September 15, 2021

The Global Emission Research Center was completed in March 2021. The work involved renovations and upgrading on the existing main building and a separate cluster of buildings (completed in 1976-1980) of the AIST Tsukuba West.
In order to achieve the goal of the Japanese government toward realizing carbon neutrality by 2050, it is important to achieve ZEB status, not only in new buildings, by renovating ones. We achieved ZEB (Net Zero Energy Building) status for the 4A Building in this project, reducing annual primary energy use in the building to net zero (usage minus generation). This was the first time Shimizu achieving ZEB status through renovation.

Net Zero Renovation Achieved through Multiple Model Simulations Early in the Design Stage and Use of the Optimal Methods

In October 2019, Japanese government announced that will inaugurate an international joint research base for zero emission technologies, as a hub of aggregated knowledge from all over the world on achieving a carbon-free society at the Green Innovation Summit 2019.
AIST established the Global Zero Emission Research Center (GZR) in response to this.

Site Plan of the Tsukuba West and the scope of renovation
Site Plan of the Tsukuba West and the scope of renovation

For renovation of the AIST buildings where advanced research in the Energy and Environment area is performed, Shimizu themed “Net Zero Renovation” with the goals of securing both performance of the research environment and energy conservation, and achieving ZEB certification for net zero annual energy usage.

The ZEB Visualizer, a ZEB evaluation and verification tool developed by Shimizu, was highly useful in design aimed at achieving ZEB status. This tool made it possible to immediately evaluate the degree to which ZEB had been attained in building energy conservation performance by using a 3D model built from BIM and other components and a library of designs related to energy conservation. Using this tool, it led us the multiple proposals being considered energy solutions simulated repeatedly, and the optimal solutions for achieving ZEB in early stage of design process.

Optimization was achieved through simulation using the ZEB Visualizer, ZEB evaluation and verification tool. We performed repeated simulations of energy conservation performance for the multiple proposals being considered, to present a timely proposal on the optimal ZEB solution for the building, and reach a consensus with the building operator.
Optimization was achieved through simulation using the ZEB Visualizer, ZEB evaluation and verification tool.
We performed repeated simulations of energy conservation performance for the multiple proposals being considered, to present a timely proposal on the optimal ZEB solution for the building, and reach a consensus with the building operator.

In this project, we achieved ZEB status in the 4A building, a two-floor reinforced concrete building.
Shingo Yamaguchi from mechanical design has this to say: “Although the building contains a large chemistry lab that uses a lot of energy, the south side of the building has deep balconies, a structure which was able to block sunlight. In addition to using the existing building, we used low-E double-glazed glass, added more thermal insulation to the exterior surfaces, and combined these with the latest energy-saving technologies for the air conditioning, lighting, and various other equipment, thereby achieving ZEB status through the optimal combination.

4A building(left)and Chemistry lab in the building(right). The excellent energy conservation performance of the existing building was combined with the latest energy-saving technologies.
4A building(left)and Chemistry lab in the building(right). The excellent energy conservation performance of the existing building was combined with the latest energy-saving technologies.

4A building(left)and Chemistry lab in the building(right). The excellent energy conservation performance of the existing building was combined with the latest energy-saving technologies.

Cross-sectional diagram of the 4A building (The blue font shows the Net Zero renovation technology used)
Cross-sectional diagram of the 4A building(The blue font shows the Net Zero renovation technology used)

More specifically, we achieved a 53% reduction in calculated energy savings on building energy usage by using separate air conditioners that operates high-efficiency, LED lighting that automatically adjusts to the amount of daylight, a hybrid exhaust system that reuses exhaust from the heat exchangers, which is normally exhausted unused, in the labs, and the Shimizu Smart BEMS (building energy management system) combined with LiB storage batteries.
Moreover, we achieved a total of 108% in energy savings in addition to generating power from the solar panels installed on the roof, thereby succeeding in “Net Zero renovation.”

We naturally paid close attention to usability in addition to calculated net energy usage. Manabu Kawaguchi, who was responsible for electrical design, commented, “After construction began, we received numerous requests from researchers who use each research facility regarding to the electrical equipment. To make the user-friendly research facility for them, we reflected the changes in the simulation, and proposed timely the best solution for ZEB.

We earned the trust of the client by achieving Net Zero renovation in this manner. Yasuto Tani from architectural design said, “There are few examples of ZEB in renovation, and technical hurdles are high. The client was pleased that we were able to achieve ZEB status while pursuing functionality as a research facility and energy conservation performance.”

We achieved a primary energy usage coefficient of -0.08 compared to the reference value through additional exterior thermal insulation, upgrading the air conditioning and lighting, and solar power.
We achieved a primary energy usage coefficient of -0.08 compared to the reference value through additional exterior thermal insulation, upgrading the air conditioning and lighting, and solar power.

Zero emission-oriented Renovation Using Reusable Materials

Shimizu themed another one, zero emission-oriented renovation that is creating new value by reusing existing materials to the extent possible to avoid generating waste. The main building was constructed 45 years ago, and built with high quality materials, using tiles for the wall surfaces and stones for the floors. We worked to refurbish and reuse them as much as possible.

Main building entrance. The wall bricks and floor tiles were reused, and the wall surfaces were showcased with lighting. Fire-resistant lumber developed by AIST was used liberally in the ceiling.
Main building entrance. The wall bricks and floor tiles were reused, and the wall surfaces were showcased with lighting. Fire-resistant lumber developed by AIST was used liberally in the ceiling.
Main building porch. Repainted metal panels and newly installed recessed lighting were arranged in a checkered pattern. For the floor, we overlaid wooden floor that provided the dual advantages of eliminating the difference in surface and reducing waste.
Main building porch. Repainted metal panels and newly installed recessed lighting were arranged in a checkered pattern. For the floor, we overlaid wooden floor that provided the dual advantages of eliminating the difference in surface and reducing waste.

Achieving Sustainable Renovation through Close Communication Between Design and Construction

This Net Zero renovation, themed zero emission-oriented incorporating many underlying technologies was completed in the short construction period of one year, including the time spent on design. Mr. Tani stated that contracted a design and build which made front-loading of design period was possible through close communication was a major reason behind the success of this project.
He said, “We were able to complete a short construction period for this project by also trying “digital fabrication” using data from the design model in construction. I experienced a real sense of how using digital technology as a platform enable the advantages to be enjoyed in both design and build construction Shimizu is using increasingly.”

From the left, Yasuto Tani, Shingo Yamaguchi, and Manabu Kawaguchi from the design headquarters, who were in charge of the project
From the left, Yasuto Tani, Shingo Yamaguchi, and Manabu Kawaguchi from the design headquarters, who were in charge of the project

Shimizu will actively incorporate digital technology in construction, and will continue to work on initiatives that contribute to achieving carbon neutrality.

A tree-shaped entrance canopy was installed in front of the main building to portray research progress and growth as a symbol of a carbon-free society
A tree-shaped entrance canopy was installed in front of the main building to portray research progress and growth as a symbol of a carbon-free society

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