A polymer composite material that can enhance heating and cooling energy efficiency has been developed domestically.
On the 17th, the National Research Foundation of Korea announced that Professor Kim Geon-woo's research team at Jeonbuk National University developed a ‘polymer composite’ that autonomously adjusts its thermal emissivity (the degree of thermal radiation energy that can be emitted from the surface of an object) according to the surrounding temperature.
Domestic heating and cooling energy consumption accounts for 40% of total energy consumption. Radiative cooling technology, which enables surface cooling without energy use, is gaining attention to improve energy efficiency; however, it has limitations as unnecessary cooling occurs even when cooling is not needed.
Radiative cooling refers to the use of materials with high thermal emissivity in the atmospheric window region of 8-12μm wavelength to easily radiate heat into space. Materials with radiative cooling technology have the drawback of causing cooling even in cold winter temperatures, further lowering surface temperatures.
To overcome these drawbacks, the development of new radiative cooling technology that responds to various temperature environments is necessary, but there has been no substantial progress.
Accordingly, the research team developed a polymer composite that can autonomously adjust thermal emissivity by using phase-change materials to increase thermal emissivity at high temperatures and decrease it at low temperatures.
Phase-change materials exhibit metallic properties at high temperatures, resulting in low thermal emissivity, while at low temperatures, they exhibit ceramic properties with high thermal emissivity. Since these characteristics are opposite to the desired properties, a method to utilize them inversely was required.
The research team nanoparticulated these phase-change materials and dispersed them within a polymer with specific thermal emissivity. They devised a method where the polymer absorbs far-infrared rays scattered when the phase-change particles exhibit metallic properties, thereby increasing thermal emissivity.
The polymer composite created through this method showed a 15% change in thermal emissivity at 70 degrees Celsius. Additionally, a heat radiator covered with the polymer composite was observed to maintain an internal temperature of 70 degrees Celsius regardless of the external temperature.
Professor Kim Geon-woo stated, "By constructing surfaces with the polymer composite developed by the research team, it is possible to maintain a constant internal temperature regardless of external temperature, thereby reducing heating and cooling energy consumption. When applied to temperature-sensitive products like batteries, it enables maintaining a stable temperature to maximize performance."
Meanwhile, this research was conducted with support from the Nano and Materials Technology Development Project and the Nano Future Materials Source Project promoted by the Ministry of Science and ICT and the National Research Foundation of Korea, as well as the Local Government-University Cooperation-Based Regional Innovation Project promoted by the Ministry of Education and the National Research Foundation of Korea.
The research results were published online on the 31st of last month in the international journal in the field of materials engineering, Composite Part B: Engineering.
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