TECHNOLOGY AND INNOVATION CENTER

Oka: As mentioned earlier, Europe leads the world in environmental awareness issues. This is evidenced in its "F-gas Regulation," which aims to curtail the greenhouse gas emissions of hydrofluorocarbons (alternative chlorofluorocarbons). The F-Gas Regulation not only prohibits the sale of products with a global warming potential (GWP) above a certain threshold, but it also sets a total volume limit known as the "quota allocation" for products below that threshold while calling for their gradual reduction.

To comply with F-gas Regulation, the Altherma 4 uses the natural refrigerant R290, which has a lower GWP than conventional refrigerants. Previously, we used the refrigerant R32, which has a GWP of 675, but replaced it with R290, which has a GWP of just 3.

The EU also has a policy called "Fit for 55," which aims to reduce greenhouse gas emissions by at least 55% compared to 1990 levels, and various regulations are being implemented to achieve this. This policy not only targets air conditioners and housing, but it is also applied to all industries, leading to even stricter regulations.

――Have environmental regulations been your only obstacle?

Hisayama: Not only are there strict regulations for environmental performance, the same is true for residential noise levels. These regulations were originally created on the assumption that boilers would be virtually silent. However, unlike boilers, which have hardly any outdoor noise sources, heat pumps always require an outdoor unit. Naturally, the Altherma 4 must also comply with these regulations.

What's more, in addition to these strict regulations, local customers are also extremely sensitive to loud noise, and there have been cases of neighbors bringing lawsuits over excessive noise. For this reason, achieving a noise level of 28dB(A), which is equivalent to a whisper, is a necessity.

Regulations differ according to the location, but if you can develop a product for Europe, which is undeniably the strictest region, then you can be confident in selling that product to other destinations. Each EU country has a subsidy system for promoting the introduction of heat pumps. Meeting the system requirements is a must to popularizing heat pumps and lowering the barriers to customer adoption.

Pictured here are the indoor and outdoor units for Altherma 4. The indoor units are available in both wall mounted and floor standing.

Development Drama｜Simultaneously Achieving Energy Efficiency, High Capacity, and Low Noise

――What problems did you encounter in changing refrigerant?

Hisayama: Let me start by giving a shout-out to the other teams that were involved in the developing the compressor, the heart of an air conditioner, and the heat exchanger. We were responsible for assembly development and noise reduction. Having said that, we can tell you what we heard from the other teams.

Oka: R290 is naturally occurring refrigerant with a low GWP. It also has low density, meaning to reach optimal performance compared to conventional refrigerants, you must increase the amount of refrigerant circulating in the refrigerant circuit. For this reason, we asked the other teams to improve the "injection" that adds refrigerant to the refrigerant circuit along with the "economizer cycle," which manages the amount of refrigerant added, and to develop a compressor that could deliver the desired performance.

However, as a result of using a low-density refrigerant while still trying to achieve the desired performance, the noise level increased due to the larger size of the equipment and higher rotational speed.

――What were the sources of noise and from where did you get help?

Oka: One source of noise was the outdoor unit fan. So, we first asked the fan development team to create a low-noise fan. Unfortunately, noise levels change depending on the fan's position relative to the heat exchanger. This is because the locations of air vortices change, and airflow can interfere with other components. To get around this, the fan development team utilized its knowledge of aerodynamics and past data. Previous experience had taught us which parts would likely become sources of noise. By leveraging our collective knowledge and conducting simulations, we worked to minimize the noise (blowing noise) of the fan and heat exchanger.

Hisayama: If the fan motor base is not sufficiently strong, small vibrations (mechanical noise) called "chatter" can occur and become a source of noise. As a countermeasure, we account for natural frequency when designing our fan motors.

A simple method to suppress machine noise is to increase plate thickness and weight, but this would have required more material and made transportation and installation more difficult, resulting in additional costs. For example, when wanting to double plate thickness, using two plates of the same thickness stacked on top of each other (forming a double wall) has been found to have an overwhelmingly greater effect on reducing noise. As a result of balancing noise reduction and plate thickness, we achieved a low noise level of 28dB(A).

In fact, double walls are a practice used in homes and automobiles. We looked at products other than air conditioners as a noise countermeasure and found the same noise-reducing technology used in homes and automobiles, so we decided to adopt it.

――What is the perspective of an engineer who grew alongside Altherma 4?

 ――Tell us about the close cooperation that continues with the European development team even after completion of development.

Hisayama: In developing Altherma 4, we collaborated with the European development team. Specifically, the Japanese development team performed the detailed technical development aiming for product commercialization, whereas the European development team adjusted the molds necessary for manufacturing and made adjustments to meet the standards required for sales.

Oka: Akutagawa played an extremely active role in development of Altherma 4. He was responsible for communicating the technology developed at TIC to the EMEA Development Center (EDC), and I felt that we were able to communicate effectively, not only about the technology itself, but also in explaining the basis for calculations.

There were instances in which the experimental results (noise results) differed between Japan and Europe, making it necessary to discuss the matter while looking at the actual product. At that time, Akutagawa also traveled alone to the site and dealt with the issue.

Akutagawa: During development, we usually communicated daily by email and weekly in online meetings with on-site visits about once every three months. As development progressed, my stays became longer, and I ended up staying there for just under two months, working hard on the development.

Because I was already familiar with English before joining the company, language was not an issue for me. However, the way of communicating and achieving goals in Japan and Europe did give me some trouble.

The European development team members were all confident people seen as professionals and specialists in their fields, whether it be measurement or analysis. However, this high level of professionalism seemed to have made communicating across disciplines somewhat difficult.

Also, while this is the result of differences in culture and customs, I felt that the Europeans had a slightly more detached way of thinking toward achieving goals than Japanese people. Nevertheless, I determinedly pushed forward with development in order to meet the approaching deadline.

Deep down inside, I felt the weight of responsibility, "If I give up now, we'll lose to other companies." Perhaps seeing me like this made them think, "Let's help that Japanese person who's come all this way," and ultimately, with the strong support of the European development team, we were able to complete the Altherma 4 and achieve our development goals.

 

How Did Daikin Achieve This?

――Do you think Daikin's unique strengths and one-team culture played a role?

Oka: As part of the movement to reduce greenhouse gas emissions, boiler manufacturers are also developing heaters using heat pumps. However, boiler manufacturers do not have the technology to perform in-house development of compressors, heat exchangers, and similar components, and are limited to procuring and assembling them.

However, our history of developing heat pumps spans many years and allows us to not only develop them in-house but also to bring globally competitive heat pumps to the market. I also believe that Daikin's unique strength lies in its development capabilities, which allows us to adapt products to destinations like Europe, which has particularly strict environmental regulations.

 

Hisayama: TIC, the development center to which we belong, is a place that handles advanced development, but the development of the Altherma 4 was a collaborative project with Air Conditioning Manufacturing Division, which actually manufactures the product.

Teams were formed across departmental boundaries, giving us the ability to overcome even seemingly impossible goals. This type of culture is another strength unique to Daikin.

Future Outlook

――What are the future prospects for heat pumps and the development team?

Hisayama: Even while saying that we successfully developed Altherma 4, this does not mean that all heat pump space and water heaters in Europe have been converted to natural refrigerants. We would like to continue to expand the scope of improvements in terms of performance and quietness. Also, although the Altherma 4 was developed as a product for the European market, we hope to expand it to China and North America in the future.

With that in mind, my personal goal is to continue identifying customer needs worldwide, tackle those needs as themes, and turn those themes into practical applications. I also believe it's important to pass on these technologies to the next generation.

Oka: The approach to home heating differs by country, whether it is Japan or the countries of Europe and North America. Europe heats the entire house with high-temperature water, whereas North America uses warm air. Rather than heat the entire home, customers in Japan demand optimal heating for each room.

Nevertheless, customers around the world all share the need for heating to be environmentally conscious. That's why I want to promote the adoption of efficient heat pumps from Europe to the rest of the world.

Akutagawa: During the development of the Altherma 4, I initially lacked specialized knowledge and found myself in a situation where I had no choice but to focus on the most immediate tasks before me. In the future, I would like to develop my own strengths that are unsurpassed by others.

――Do you have a special message for future Daikin colleagues?

Hisayama: We are a company that teams up with partners worldwide and looks forward to working with people who want to work globally or who are interested in being posted overseas in the future.

Oka: We are looking for people who would like to join us in developing heat pumps to preserve the global environment.

Akutagawa: In addition to Europe, the United States, and China, we are also focusing on the Global South and have recently built a new factory in India. By all means, we hope to work with people who want to work globally.

 

※Information and profiles are current at the time of the interview.

Kazushi Hisayama
Position at TIC: Senior Engineer

Joined company: April 2008
Hometown: Hyogo Prefecture
Technology responsible for: Refrigeration cycle technology, noise reduction technology, space and water heating development technology
Thoughts and enthusiasm for technology: I would like to continue planning and commercializing the industry's No. 1 low-noise and smash hit product.

Yasuhiko Oka
Position at TIC: Team Leader

Joined company: April 1992
Hometown: Osaka Prefecture
Technology responsible for: Refrigeration cycle technology
Thoughts and enthusiasm for technology: I would like to continue working on energy-saving heat pump technology, which can produce three to four times the output of thermal energy for every one unit input of electrical energy.

Kazuki Akutagawa
Position at TIC: Technology and Innovation Center

Joined company: April 2019
Hometown: Hiroshima Prefecture
Technology responsible for: Structural design, mainly noise reduction
Thoughts and enthusiasm for technology: I want to create technologies that may seem far-fetched now from today's perspective but will become common practice in the future.