Equipment initiatives that realize the "fusion of 'green' and 'innovation'"

Grand Green Osaka was born from the redevelopment of the area north of Osaka Station, and is a new town that aims to achieve harmony between the city and nature. The approximately 9-hectare site is home to a vast urban park and includes a complex of facilities, cultural facilities, and a large covered plaza. The South Tower, which we were involved in Architectural Design of, is a building located in front of JR Osaka Station that brings together commercial facilities, offices, a hotel, MICE facilities, and more. Here, we have brought together the technologies and know-how of each company to create a sustainable urban space where people can live in peace and security.

This time, we will explain their environmentally friendly technologies and efforts to prepare for large-scale disasters.

Grand Green Osaka has introduced many environmentally friendly technologies in line with the redevelopment. In particular, the heat source equipment, which has a major impact on the energy used for heating and cooling, has been equipped with multiple systems with different characteristics, such as district heating and cooling and cooling and individual heat sources. By operating these efficiently, the project aims to reduce the environmental impact of the entire redevelopment area, and is working to achieve the overall project concept of "combining greenery and innovation."

Highly efficient district heating and cooling has been adopted as the main heat source, with new heat supply plants installed in the basements of both the South Building and the North Building. Both plants are connected by heat exchange ducts buried underground in the park, and heat can also be exchanged with existing plants installed in surrounding facilities, enabling highly efficient energy use throughout the area.

Other cutting-edge equipment that has been installed includes an individual heat source aquifer thermal storage system, a cogeneration system (CGS), and a biogas power generation system. Each system reduces energy consumption and CO₂ emissions, and by operating the optimal equipment according to the season and time of day, the system is able to achieve further energy and CO₂ savings.

Grand Green Osaka has introduced an aquifer thermal storage system across its vast site as a method of utilizing the abundant groundwater unique to the Umeda area. Aquifer thermal storage is a system that uses groundwater from an aquifer that is rich in water and located approximately 40 to 50 meters underground as a heat storage medium, and Grand Green Osaka block will be the first in Japan to introduce such a large-scale aquifer thermal storage system.

Heat pumps inside buildings generate warm waste heat during cooling operation. Normally, this heat is released into the atmosphere using cooling towers, but with this system, this heat is stored in an aquifer and used as a heating source in the winter. Similarly, the cold waste heat generated during heating in the winter is also stored in the aquifer and used as a cooling heat source in the following summer. In this way, using the aquifer as a "natural heat storage tank" makes it possible to circulate heat across seasons, allowing for efficient heating and cooling operation throughout the year, while also contributing to the mitigation of the heat island effect by reducing the amount of heat released into the atmosphere.

When implementing the system, we considered and planned the placement and separation distance of the wells dug from the heat pump to the aquifer to ensure efficient heat storage. The aquifer thermal storage system consists of two wells: a hot well that stores hot waste heat, and a cold well that stores cold waste heat. However, if the wells are too close to each other, the heat stored in each well will mix and operation will be inefficient. The appropriate well separation distance depends on how much heat is stored and used as a heat source during the summer and winter. Therefore, we simulated the operation of the heat source in each season to determine the appropriate distance from a functional standpoint, and considered the appropriate placement that would be consistent with the exterior plan.

The South Building takes advantage of the unique characteristics of a large-scale facility, including commercial facilities and kitchens for two hotel restaurants, to create a system within the building to treat the food waste and wastewater that is steadily generated daily.

The core of this system is biogas power generation. Food waste and kitchen wastewater sludge are treated and eliminated within the facility, and the methane gas produced in the process is used to generate electricity and heat. Furthermore, this electricity and heat are reused as a power source for the waste treatment system, reducing the energy required for treatment.

The introduction of this system eliminates the need to transport waste to external facilities, reducing CO₂ emissions associated with transportation and contributing to further reducing the environmental impact.

During the implementation stage, we worked with the operator from the planning stage to predict the amount of food waste and wastewater that would be generated once the facility began operation, and after extensive discussions about the appropriate scale of the system, we designed the optimal system.

The South Tower is a large-scale complex that forms part of Osaka's urban economy. Not only does it ensure business continuity in the office by keeping its facilities operational in the event of a disaster, but as a large facility located in front of Osaka Station, it also plays an important role in responding to people who are unable to return home.

First, in constructing a building that is resistant to natural disasters, the architectural plan takes into consideration the placement of important equipment rooms as a flood prevention measure. Important rooms such as the extra-high voltage electrical room, communications equipment room, generator room, CGS room, and disaster prevention center are located on the second floor or higher to prevent them from functioning due to flooding. Furthermore, flood barriers and raised concrete walls are installed above ground to prevent water from entering the building as much as possible.

Furthermore, to supply power in the event of a power outage, two oil-fired emergency generators and two gas-fired regular generators (CGS) have been installed, which will allow the operation of some of the building's core facilities such as some of the lighting, elevators, and water pumps, allowing the use of some of the building's common areas and hotel common areas, and are also designed to be able to supply power to air conditioning, lighting, and outlets in the office areas according to tenant requests. These can operate for more than three days on oil alone even in the event of a power outage, and will always be able to supply power as long as the gas supply is not interrupted.

In addition to installing a disaster preparedness stockpile warehouse, we have also prepared a temporary accommodation space that can be powered by a generator even in the event of a power outage, allowing lighting, electrical outlets, and air conditioning to be used.An emergency drainage tank has also been installed underground, so toilets near the temporary accommodation space can be used even in the event of a sewage outage.Minor-purpose water from an underground pit is used as the water source for flushing the toilets, and in the event of a shortage, water from the heat storage tank can also be used.
The cogeneration system and heat storage tank are designed to have multiple effects, contributing to efficient heat source operation and peak cutting during normal times, and also supporting people who are unable to return home in emergencies.

Furthermore, we are planning to provide power to Umekita Park South Park as well, contributing to improving business continuity not only in the South Building but throughout the Umekita area.

In line with urban development concepts, Grand Green Osaka has implemented methods to reduce environmental impact by taking advantage of the site's characteristics, a resource recycling system, and various measures to strengthen the city's disaster prevention capabilities. In addition to receiving certifications such as "ZEB Oriented (office portion)" and "CASBEE S rank," the building has also received the following certifications for its environmental performance and sustainability.