Regional Heating and Cooling Gains Attention in the Thermal Energy Sector as a Step Toward Achieving Carbon Neutrality by 2050
Development of “AI District Heating and Cooling” (commonly known as “AI Chirei”) to Reduce CO2 Emissions and Costs Using AI
Demonstration tests began in Nagoya in May 2022

Nikken Sekkei Ltd., Nikken Sekkei Research Institute Ltd., Toho Gas Co., Ltd., Sumitomo Corporation Machinex Co., Ltd., and Araya Co., Ltd. have developed “AI District Heating and Cooling” (commonly known as “AI Chirei”), a system that uses AI to solve challenges in existing district heating and cooling systems.Starting in May 2022, a demonstration experiment of “AI Chirei” will be conducted in the Nagoya Sakae 3-chome North District Heating and Cooling system.

District heating and cooling is a critical urban infrastructure system that enhances environmental sustainability, economic efficiency, and disaster resilience by utilizing unused energy within a region to centrally generate heating and cooling energy on an area-wide basis and supply it to multiple buildings in the area.As part of efforts to achieve carbon neutrality by 2050 and build a decarbonized society, district heating and cooling—which is expected to reduce CO₂ emissions—is attracting significant attention in the thermal energy sector.

District heating and cooling systems in Japan were introduced starting in the 1970s as a measure to combat air pollution caused by rapid economic growth, and there are currently 133 such facilities nationwide. Approximately 90 percent of these existing facilities were completed more than 20 years ago, and their energy efficiency is steadily declining. Furthermore, accurately forecasting consumer demand and operating heat sources accordingly is difficult even for experienced operators; therefore, reducing CO₂ emissions through retrofits—including a review of operating methods—is essential. Furthermore, not only for existing systems but also for district heating and cooling systems newly constructed as part of large-scale developments, efficient operation that reflects consumer demand for heating and cooling is essential for achieving carbon neutrality.

The solution we’ve developed is “AI Chirei,” which uses AI to address these challenges. By simply installing an edge PC equipped with AI software and having it read the operational data, you can achieve CO2 reductions at low cost and in a short timeframe. Since it only requires installing the edge PC, there’s no need to halt operations.

To achieve energy savings, it is crucial to eliminate waste by operating only the necessary number of heating and cooling units when needed. The AI we have developed can predict the demand for heating and cooling (heat output and water flow) several hours in advance, enabling operation with the minimum number of units required.

AI assesses the indoor temperature and heat load at the consumer’s location and adjusts operation accordingly—raising the chilled water temperature during cooling and lowering the hot water temperature during heating. This improves the efficiency of the heat source unit.

As heating appliances are used over time, their energy efficiency declines, making it difficult to determine which appliance is the most energy-efficient. Now, AI identifies the appliance with the highest energy efficiency and prioritizes its operation.

As the first step in the “AI Chirei” pilot program, we will conduct a pilot test of one of the three AI systems—specifically, the AI for forecasting heat and water supply demand—at the Sakae 3-chome North District Heating and Cooling Facility operated by Toho Gas.

Nagoya Sakae 3-chome North District District Heating and Cooling System

May 2022–March 2024

Nikken Sekkei / Nikken Sekkei Research Institute: Development of demonstration scheme, renovation design, and effectiveness verification
Sumitomo Corporation Machinex and Araya: Development and Customization of AI Programs
Toho Gas: Provision of demonstration site; identification of operational challenges

We conducted a simulation using AI for heat and water supply demand forecasting based on historical data. We have confirmed that the system can predict heat demand with 99% accuracy.

Based on the insights gained from this demonstration experiment, we will work toward reducing CO₂ emissions by leveraging the commissioning*1 technology that Nikken Sekkei has cultivated over many years. The “AI Chirei” system developed for this project can also be applied to heating systems in large-scale development buildings, hospitals, and other facilities.

*1 During the demonstration phase, target performance, target values, and the conditions for achieving them are clarified; based on this, the details of the demonstration and operational status are reviewed, and the actual performance is quantitatively evaluated.

Nikken Sekkei, Ltd.
Representative: Representative Director President and CEO Atsushi Omatsu
Address: 2-18-3 Iidabashi, Chiyoda-ku, Tokyo

Nikken Sekkei Research Institute Co., Ltd.
Representative: Hiroki Asakura, Representative Director and President
Address: 2-18-3 Iidabashi, Chiyoda-ku, Tokyo

Toho Gas Co., Ltd.
Representative: Nobuyuki Masuda, Representative Director President and CEO
Address: 19-18 Sakurada-cho, Atsuta-ku, Nagoya City

Sumitomo Corporation Machinex Co., Ltd.
Representative: Akihiro Sahashi, Representative Director President and CEO
Address: 10th and 11th Floors, Sumitomo Corporation Takebashi Building, 1-2-2 Hitotsubashi, Chiyoda-ku, Tokyo

Araya Co., Ltd.
Representative: Ryota Kanai, Representative Director
Address: 24th Floor, Ark Mori Building, 1-12-32 Akasaka, Minato-ku, Tokyo

株式会社日建設計 広報室 TEL：03-5226-3030（代表）