Promoting highly energy efficient inverter-based air conditioners is imperative for the global environment. To achieve this, low-cost inverter technology is needed.
However, Europe and China have established stricter standards than those in Japan for the current harmonics generated by inverters. To comply with these harmonic regulations, topological measures, such as increasing reactor capacity and adding PFC circuits, had to be implemented and are one reason for the high cost of inverters.
To resolve this issue, Daikin has promoted technology development of electrolytic-capacitor-less inverters that provide both low inverter cost and compliance with harmonics regulations.
This technology eliminates the need of electrolytic capacitors, large reactors, and PFC circuit—all of which are high-cost parts—and reduces harmonic components of the input current through inverter control to meet the strictest harmonics regulations in the world. Figure 1 shows a circuit diagram of the electrolytic-capacitor-less inverter for residential air conditioners that use a single-phase power supply. As shown in the figure, it is a very simple circuit configuration. Similarly, we have also developed an electrolytic-capacitor-less inverter for commercial air conditioners that use a three-phase power supply.
- Development of the electrolytic-capacitor-less inverter technology
- Compliance with the harmonics regulations
Permanent Magnet Motor For Energy Saving and Resources Saving
Because compressors consume a large amount of electric power compared to other air conditioner components, reducing power consumption of the compressor motor is important. To improve the energy efficiency of motors, particularly for low- to mid-speed rotation compressors, the practical application of a new type of motor was needed. The key to reducing power consumption is to (1) reduce power loss by decreasing motor current and (2) increase the rotation speed of motors without decreasing efficiency. Achieving both (1) and (2) had been thought impossible. With this understanding, we focused on a structure in which a neodymium rare earth permanent magnet is embedded inside a motor rotor. Seeing the results of the electromagnetic field simulation shown in Figure 1, we improved energy efficiency in a wide range from low- to high-speed rotation without sacrificing high efficiency in the low- to mid-speed rotation range even when air conditioning cooling and heating performance needs to be increased. Specifically, we were the first in the world to succeed in theoretically and experimentally demonstrating a 95% improvement in motor efficiency, which is an unprecedented level for small-capacity home appliance motors, and this led to halving annual power consumption of air conditioners (halving the electricity cost). Figure 2 shows the world's-first practical application of a small-sized air conditioning motor that significantly reduces use of the heavy rare-earth element dysprosium and helps ease the resource issue for rare-earth elements.
- Further improvement in motor speed and efficiency
- Miniaturization of compressor motors by using new electromagnetic materials and new motor types
Compressor, the Core of Air Conditioners
Developing differentiated technologies that keep attracting customers
Daikin's strengths lie in its original technologies for energy-saving, highly efficient compressors in inverter products. Compressors account for 80-90% of the electricity used by air conditioners. That means, reducing power consumption for compressors drastically improves air conditioning energy efficiency. In recent years, energy efficiency has become an issue that cannot be ignored either economically or environmentally. This prompted Daikin to tackle this challenge using its proprietary technologies. Among them, there are four noteworthy technologies—(1) swing compressor technology that reduces leakage loss, (2) scroll compressor technology that provides back-pressure control, (3) single screw technology that delivers high efficiency, and (4) magnetic bearing technology that ensures high reliability for centrifugal compressors. Because Daikin is the only company capable of this, the market turns to Daikin, and it is the one that people continue to choose. Transcending organizational boundaries, Daikin will further promote collaborative creation with external parties and continue to create the standards of the future.
- Swing compressor technology that reduces leakage loss
- Scroll compressor technology that provides back-pressure control
- Single screw technology that delivers high efficiency
- Magnetic bearing technology that ensures high reliability for centrifugal compressors
Compact Heat Exchanger Technology
The function of heat exchangers is to transfer heat between the refrigerant, a medium for carrying heat in the heat-pump cycle, and the air used for air conditioning. Heat exchangers consist of heat transfer tubes where refrigerant flows inside and fins, which extend the heat transfer area used for exchanging heat to air.
To improve energy efficiency in the heat pump cycle, heat exchanger performance has been improved by reducing the diameter of heat transfer tubes and modifying fin shape. However, in recent years, it has become necessary to not only improve each element but also to increase the size of the heat exchanger. As a consequence, this has caused increases in both product size and refrigerant amount.
To overcome these challenges, Daikin has promoted use of microchannel heat exchangers that improve performance and reduce heat exchanger size. Microchannel heat exchangers use flat, multi-hole heat transfer tubes that consist of refrigerant channels with a diameter of less than 1mm. These tubes can improve heat exchanger performance by providing more heat transfer area for refrigerant side while reducing airflow pressure drop. When this type of heat exchanger is used for air conditioners with heat pumps, there may be an issue of moisture retention from condensed water or frost generated on the fin surface due to its structure. However, improvement of the fin shape has resolved this problem.
Microchannel heat exchangers are much smaller and lighter than conventional heat exchangers and have decreased the amount of refrigerant while maintaining the same capacity.
- Microchannel heat exchangers
- Technology for reducing the size and weight of heat exchangers
Fan and Airflow Technology
The role of an air conditioning fan is to contribute to the environment and society by providing a comfortable living environment to users through efficient heat exchange and airflow control while lessening noise. To achieve these aims, Daikin has developed advanced fans using biomimetics and provide indoor circulation airflow using the Coanda effect.
However, the conventional fan design standard and airflow structure have increasingly encountered difficulties in meeting diverse global needs calling for chic designs and low-sound products.
To resolve the issue, we developed the residential air conditioner “risora,” which has optimized design for both airflow and energy efficiency. The product also adopts multi-connected saw-edged, cross-flow fans (see figure). Furthermore, simultaneously simulating the flow and sound fields (see figure) enables analysis of the sound generation mechanism for development of low-sound products with only minimum noise disturbing comfort.
In the future, we will take into consideration the impact of external factors (building layout, thermal resistance, outdoor air, sunlight, etc.) on air conditioners and people’s sense of cooling and heating to research and develop the airflow control technology that provides an even more comfortable environment.
- Multi-connected saw-edged cross-flow fans
- Airflow control technology
- Low sound
Refrigerant Control Technology
A heat pump cycle is a cycle for heat exchange with ambient air through the process of condensation and evaporation of refrigerant that flows through the equipment circuit. Refrigerant control refers to the technology to control the state and flow rate of refrigerant in this heat pump cycle to transfer the necessary amount of heat to the needed area while maintaining equipment reliability.
To maintain equipment reliability, it is important to control the behavior of refrigeration oil that flows through the equipment circuit along with refrigerant. How to properly control these two substances is the key to this technology.
Multi-split systems that connect multiple indoor units to a single outdoor unit are commonly used in commercial buildings. Among them is a system called heat-recovery, which is capable of operating in a mixed environment of indoor units for cooling and indoor units for heating. Refrigerant control of such systems is especially complicated.
Although we have improved the capacity and functionality of equipment through advanced refrigerant control, the demand for energy savings and comfort has recently increased. To achieve refrigerant control that meets these needs, we are working on research and development of energy-saving control with enhanced coordination between indoor and outdoor units (see figure) and operational optimization utilizing refrigerant behavior modeling.
- Load estimation and forecast of necessary capacity
- Refrigerant behavior modeling technology
IAQ Technology to Help People Stay Healthy
IAQ is short for Indoor Air Quality.
Air is a substance that people take in the most in one day and contains elements that affect people’s health. For example, a large amount of formaldehyde contained in new building materials causes headaches and nausea (sick building syndrome). Pollen in the air causes allergic symptoms. IAQ technology aims to improve the quality of indoor air and help people become and stay healthy. Specifically, we have desiccant technology that enables simultaneous operations of humidification/dehumidification and ventilation. Streamer technology decomposes and removes gas and bacteria for deodorization and sanitation. This technology is also used to keep air conditioners clean inside (Round Flow Cassette released in 2018). We also work on visualization of air quality (development of sensing technology), development of solutions utilizing the sensing technology, and development of new environmental control technology to control temperature, humidity, airflow, wall temperature, and air purity through the monitoring of human conditions.
- Desiccant technology
- Streamer technology
- Sensing technology development
Energy-saving Technology for High Performance Air Filters
Conventionally, high performance air filters have been mainly used in the electronic industry as represented by the field of semiconductor devices. However, applications have been expanding due to the widespread use of these filters in the pharmaceutical, food, healthcare, and other industries that must prevent cross-contamination and biological contamination while facing an ever-growing need for indoor air purity. The Daikin Group aims not only to design clean and safe air but also to improve energy efficiency and reduce the TCO for high efficiency air filters. For example, the Daikin Group has been deepening the multi-elemental fluoropolymer membrane technology, a nanofiber technology of which the Daikin Group succeeded in mass production, to develop air filter media that achieve both lower pressure drop and longer service life. For instance, the conventional glass fiber HEPA filter media have the pressure drop of approx. 300 Pa at 5.3 cm/sec, fiber diameter of 0.5 to 1.0 μm, pore diameter of approx. 3 μm, and thickness of approx. 300μm. In contrast, the multi-elemental fluoropolymer HEPA filter media have pressure drop of approx.150Pa at 5.3 cm/sec, fiber diameter of 0.05 to 0.2 μm, pore diameter of approx.1.5 μm, and thickness of approx. 100 μm, one-third of the thickness of the conventional filter media.
- Fluoropolymer membrane formation technology
- HEPA filter media technology that improves energy efficiency and reduces TCO
Automotive market is in a time of changes based on the trend of connected, shared, autonomous and electrification.
Daikin provides Fluoro based material solutions to improve the efficiency, safety, and optimization of combustion engine, electrification challenges.
- Fluorochemical technology
The rise of clouds, big data interactions, and instant data has an unprecedented impact on the manufacture of semiconductors. They seriously challenge the Moore scaling system and invite semiconductor device producers to consider new scaling paths. Since decades, Daikin serves the semiconductor industry's objective: maintain the technology scale up in overall performance.
- Fluorochemical technology
The consumer electronics market is also characterized by a growing consciousness of users regarding sustainability. For consumers and leaders, sustainability is becoming more vital and the demand for manufacturers to develop and deliver sustainable products is growing. Daikin expertise serves the value chain achieving the most demanding consumer needs.
- Fluorochemical technology
With the global population growing and industrialization on the rise in developing countries, humanity’s appetite for energy has reached unprecedented levels. It is expected that by 2040, the world’s energy consumption will increase by almost 50%. Every day, Daikin contributes to the future energy challenges relying in diversification, efficiency, and storage.
- Fluorochemical technology
Home and living, Healthcare
Delivering genuine, affordable and sustainable home and living is one of the greatest challenges for the future. It has become mandatory for the players in the home and living field to offer new methods, smarter materials, better connections and above all more comfortable. Daikin is committed to making this future possible.
The burden of the healthcare industry is triple. As performance and safety tie the whole value chain, manufacturers are continuously looking area for cost-process optimizations with no impact on their first obligations. Daikin is committed to helping the industry in meeting the highest standards for patients while enhancing the production processes and improving medical equipment performances.
- Fluorochemical technology
Daikin’s temperature control and freshness preserving technologies in the refrigeration field contribute to safe, reliable, and stable food supply and energy savings. Advancing conventional technologies allowed us to provide even more value. For example, temperature and humidity control for refrigeration warehouses enables control of temperature rise during defrosting, temperature decrease through the humidification function, and humidity control at low temperatures. In addition, the technology to further save energy of refrigeration equipment greatly helps improve defrosting efficiency and energy efficiency in freezing. The most important technologies of safe and reliable food supply and long-term freshness preservation for stored items have also improved to keep them in better condition than before. Specifically, we provide air quality control (CA, automated ventilation, ethylene removal, etc.), disinfection, mold prevention, and quick freezing (freezing at -60°C, freezing of tuna, etc.) for preserving the freshness of vegetables and fruits. To provide such value, we need technologies, such as for preventing deterioration of food quality when frozen and defrosted and for sensing and refrigeration to preserve freshness in a long term. Disinfection, sanitation, sterilization, and self-cleaning materials are also necessary. To provide these solutions, we need to go beyond Daikin and work with external parties to continuously contribute to the world through safe, reliable, and stable food supply and energy savings.
- Preventing deterioration of food quality when frozen and defrosted
- Long-term freshness preservation
- Disinfection, sanitation, sterilization, and self-cleaning materials
- Technology to add value to food in storage
Energy-saving, Low-sound Home Medical Equipment
Even in the medical equipment field where cutting-edge, advanced technologies are always required, Daikin’s unique, accurate process technology has satisfied customer needs. For example, we have incorporated the compressor and inverter technologies developed in the air conditioning field to provide industry-leading comfort. We produce and sell easy-to-use home oxygen therapy equipment to help home oxygen therapy patients feel comfortable both inside and outside the home and improve their quality of life (QoL). For example, our oxygen concentrator integrates energy-saving inverter technology and highly-accurate process technology to optimize compressor control. This led us to achieve industry-leading energy efficiency. Furthermore, optimal positioning of four heads mounted on the low-sound compressor reduces vibrations between moving heads and enables smooth rotational movement, resulting in achieving the lowest sound level in the industry. In addition to such high energy efficiency and low sound level, the integration of highly accurate process technology and surface modification technology allows us to achieve industry-leading longevity (2,000 hours) for oil-free compressors and ensures that consumers can use the product safely for a long time. The small size of the product is also important for home medical equipment. In-house development of the four-head compressor dedicated to oxygen concentrators allows us to achieve industry-leading compactness and lightweight of the equipment.
- Energy-saving design
- Low-sound design
- Improved longevity
- Small, lightweight, compact equipment
Hybrid Oil Hydraulic System Technology
With growing requirements for high efficiency motors and advancement in technological innovation using IoT worldwide, we are working to meet the needs for significantly improving the energy efficiency, performance, and functionality of industrial hydraulic equipment. Not only that, we also have developed hybrid oil hydraulic products by improving the oil hydraulic technology based on the motor inverter technology in the air conditioning field. For example, real-time demand control, in which a variable-speed motor with high responsiveness discharges a necessary amount of oil at a necessary time, and pressure retention control, which simply offsets oil leakage through ultra-low-speed operations, enable high energy efficiency and low heat generation. The latest IPM motor mounted on the equipment is also small, compact, and highly efficient. The pump is operated at a low speed when the flow rate is low to achieve a low sound level. In addition to the feedback control for motor rotation speed and pressure sensors, our unique algorithms for controlling pressure and flow rates have improved the linearity of flow characteristic that had been affected by oil temperatures before and help significantly reduce warm-up time and improve product yield. Furthermore, small variations between individual products simplify initial adjustment of equipment. To perform hybrid control, many sensors are originally mounted on the equipment. Information collected through these sensors can be easily retrieved through communication and can be used for decision-making on preventive maintenance.
- Energy-saving and low heat generation
- Low-sound design
- Stable reproductivity and liner characteristic
- IoT connectivity