Building and Inheriting Urban Infrastructure: 40 Years of Minato Mirai

Minato Mirai 21 District is an area covering 186 hectares that began construction in 1983 to coincide with the 1989 Yokohama Exposition and has developed over more than 40 years.

The central district of Minato Mirai 21 District is crisscrossed with utility tunnels, and a heat supply system is employed that uses chilled water and steam pipes within these tunnels to provide air conditioning and hot water to the district. This heat supply is provided by "Minato Mirai 21 Heat Supply Co., Ltd.," which was established during the Yokohama Exposition. Starting with supplying heat to the pavilions of the Yokohama Exposition, it now supplies heat to the entire Minato Mirai central district (141 hectares). It is the largest single supply area in Japan, and the boilers (machines that produce steam, the heat source) installed in the plant are also the largest in Japan, while the chillers (machines that produce chilled water, the heat source) have one of the world's largest production capacities.

Currently, our Urban Energy Planning Department is working on the renewal plans for the "Center Plant," which was completed for the Yokohama Exposition, and the "Second Plant," located underground in "Queens Square," which was completed in 1997. We are also working on the "Third Plant New Construction Project," which is planned for the "Minato Mirai 21 Central District Block 52," and the optimization of the regional piping network. In addition, we are conducting the examination, planning, design, and Construction Supervision of infrastructure facilities that support the region.

The "Center Plant," which began operations in 1989, underwent a major renovation project from 2014 to 2017, involving the installation of new boilers and cooling towers and the replacement of eight chillers. Furthermore, the "Second Plant," which began operations in 1997, underwent seven expansion projects after its completion, followed by a large-scale renovation from 2020 to 2017, which involved replacing and installing eight chillers and five cooling towers.

These renovation projects aim to address the increasing heat demand resulting from development in the area, improve plant efficiency (COP = Coefficiency of Performance/Overall Energy Efficiency), and ensure a more stable supply. Simply removing old machinery and installing new equipment can have a positive effect. In addition, reducing and streamlining transport power and planning for auxiliary equipment also impacts COP, so detailed considerations and efficiency studies of the piping supply network contribute to a significant improvement in the plant's COP.

Personally, I started working for DHC in 2021.

I had been involved in building MEP Engineering for over 15 years, but working with DHC involved a lot of unfamiliar terminology and considerations I had never encountered before. On top of that, because the work involved infrastructure facilities that were already in operation, we were required to consider extremely tight schedules, such as how to replace large machinery while maintaining heat supply.

In a situation where I was completely unfamiliar with the process, I was able to see the renovation work on "Plant No. 2" through to completion with the help of our veteran employees.

Japan has 132 district heating and cooling supply areas (according to the Japan Heating Association website), and chillers, boilers, and power receiving and transforming equipment generally need to be replaced every 25 to 35 years. Currently, many DHC plants that began operation in the 1990s are reaching the end of their service life, and there is a lot of work starting from developing replacement plans.

While we consider future additions and equipment when constructing new buildings, it's necessary to re-evaluate whether the plan is still appropriate when it's time for replacement, given changes in social needs and heat demand forecasts.

Looking into the renewal plan for the "Second Plant," we see that the first review aimed at energy conservation was conducted in 2007, 10 years after the start of supply, and the second review aimed at further energy conservation and business cycle development (BCD) in 2019. It is clear that the renewal is steadily progressing in accordance with the plan drafted at that time, which extended to 2040.

It's a job where we all take over a very long-term project, from formulating a renewal plan 20 years after it starts operating, to carrying out the construction 25 to 35 years later.

As development in the Minato Mirai 21 district progresses, the amount of heat needed for heating and cooling will also increase.

Therefore, in addition to the two existing plants, construction is underway on a new "third plant." The third plant will be the first to supply hot water to the Minato Mirai district (the existing plants supply steam). Furthermore, preliminary studies of the heat supply piping network have shown that supplying cold energy from the third plant will reduce the amount of power needed to transport it to the surrounding area.

The "Third Plant" is planned for the basement of the new building, and the plant construction will proceed simultaneously with the building's construction. This presents different challenges compared to plant renovation projects, such as managing the application schedule for the new building and coordinating with the building's construction work. On the other hand, it allows us to undertake new initiatives, and we believe that by leveraging our knowledge and experience in building MEP Engineering and making diverse proposals, we can create an even better DHC plant.

Above all, I feel incredibly fortunate to be involved in a job as architectural design and construction supervision that offers a great sense of accomplishment, as I can watch the building take shape day by day and work alongside the completion of the DHC facilities that I planned for it.