Chemical+Engineering
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KAIST Develops Glare-Free, Heat-Blocking 'Smart Window'... Applicable to Buildings and Vehicles
• Professor Hong Chul Moon of the Department of Chemical and Biomolecular Engineering develops RECM, a next-generation smart window technology, expecting cooling energy savings and effective indoor thermal management.
• When using the developed RECM, a significantly superior temperature reduction effect is observed compared to conventional windows.
• With a 'pedestrian-friendly smart window' design that eliminates glare by suppressing external reflections, it is expected to be adapted in architectural structures, transportation, and more.
< (From left) First author Hoy Jung Jo, Professor Hong Chul Moon >
In the building sector, which accounts for approximately 40% of global energy consumption, heat ingress through windows has been identified as a primary cause of wasted heating and cooling energy. Our research team has successfully developed a 'pedestrian-friendly smart window' technology capable of not only reducing heating and cooling energy in urban buildings but also resolving the persistent issue of 'light pollution' in urban living.
On the 17th of June, Professor Hong Chul Moon's research team at KAIST's Department of Chemical and Biomolecular Engineering announced the development of a 'smart window technology' that allows users to control the light and heat entering through windows according to their intent, and effectively neutralize glare from external sources.
Recently, 'active smart window' technology, which enables free adjustment of light and heat based on user operation, has garnered significant attention. Unlike conventional windows that passively react to changes in temperature or light, this is a next-generation window system that can be controlled in real-time via electrical signals.
The next-generation smart window technology developed by the research team, RECM (Reversible Electrodeposition and Electrochromic Mirror), is a smart window system based on a single-structured *electrochromic device that can actively control the transmittance of visible light and near-infrared (heat).
*Electrochromic device: A device whose optical properties change in response to an electrical signal.
In particular, by effectively suppressing the glare phenomenon caused by external reflected light—a problem previously identified in traditional metal *deposition smart windows—through the combined application of electrochromic materials, a 'pedestrian-friendly smart window' suitable for building facades has been realized.
*Deposition: A process involving the electrochemical reaction to coat metal ions, such as Ag+, onto an electrode surface in solid form.
The RECM system developed in this study operates in three modes depending on voltage control.
Mode I (Transparent Mode) is advantageous for allowing sunlight to enter the indoor space during winter, as it transmits both light and heat like ordinary glass.
In Mode II (Colored Mode), *Prussian Blue (PB) and **DHV+• chemical species are formed through a redox (oxidation-reduction) reaction, causing the window to turn a deep blue color. In this state, light is absorbed, and only a portion of the heat is transmitted, allowing for privacy while enabling appropriate indoor temperature control.
*Prussian Blue: An electrochromic material that transitions between colorless and blue upon electrical stimulation.
**DHV+•: A radical state colored molecule generated upon electrical stimulation.
Mode III (Colored and Deposition Mode) involves the reduction and deposition of silver (Ag+) ions on the electrode surface, reflecting both light and heat. Concurrently, the colored material absorbs the reflected light, effectively blocking glare for external pedestrians.
The research team validated the practical indoor temperature reduction effect of the RECM technology through experiments utilizing a miniature model house. When a conventional glass window was installed, the indoor temperature rose to 58.7°C within 45 minutes. Conversely, when RECM was operated in Mode III, the temperature reached 31.5°C, demonstrating a temperature reduction effect of approximately 27.2°C.
Furthermore, since each state transition is achievable solely by electrical signals, it is regarded as an active smart technology capable of instantaneous response according to season, time, and intended use.
< Figure 1. Operation mechanism of the RECM smart window. The RECM system can switch among three states—transparent, colored, and colored & deposition—via electrical stimulation. At -1.6 V, DHV•+ and Prussian Blue (PB) are formed, blocking visible light to provide privacy protection and heat blocking. At -2.0 V, silver (Ag) is deposited on the electrode surface, reflecting light and heat, while DHV•+ and Prussian Blue absorb reflected light, effectively suppressing external glare. Through this mechanism, it functions as an active smart window that simultaneously controls light, heat, and glare. >
Professor Hong Chul Moon of KAIST, the corresponding author of this study, stated, "This research goes beyond existing smart window technologies limited to visible light control, presenting a truly smart window platform that comprehensively considers not only active indoor thermal control but also the visual safety of pedestrians." He added, "Various applications are anticipated, from urban buildings to vehicles and trains."
< Figure 2. Analysis of glare suppression effect of conventional reflective smart windows and RECM. This figure presents the results comparing the glare phenomenon occurring during silver (Ag) deposition between conventional reflective smart windows and RECM Mode III. Conventional reflective devices resulted in strong reflected light on the desk surface due to their high reflectivity. In contrast, RECM Mode III, where the colored material absorbed reflected light, showed a 33% reduction in reflected light intensity, and no reflected light was observed from outside. This highlights the RECM system's distinctiveness and practicality as a 'pedestrian-friendly smart window' optimized for dense urban environments, extending beyond just heat blocking. >
The findings of this research were published on June 13, 2025, in Volume 10, Issue 6 of 'ACS Energy Letters'. The listed authors for this publication are Hoy Jung Jo, Yeon Jae Jang, Hyeon-Don Kim, Kwang-Seop Kim, and Hong Chul Moon.
※ Paper Title: Glare-Free, Energy-Efficient Smart Windows: A Pedestrian-Friendly System with Dynamically Tunable Light and Heat Regulation
※ DOI: 10.1021/acsenergylett.5c00637
< Figure 3. Temperature reduction performance verification in a miniature model house. The actual heat blocking effect was evaluated by applying RECM devices to a model building. Under identical conditions, the indoor temperature with ordinary glass rose to 58.7°C, whereas with RECM in Mode III, it reached 31.5°C, demonstrating a maximum temperature reduction effect of 27.2°C. The indoor temperature difference was also visually confirmed through thermal images, which proves the potential for indoor temperature control in urban buildings. >
This research was supported by the Nano & Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT and the internal research program of the Korea Institute of Machinery and Materials.
2025.06.20 View 2343 -
KAIST Research Team Creates the Scent of Jasmine from Microorganisms
The fragrance of jasmine and ylang-ylang, used widely in the manufacturing of cosmetics, foods, and beverages, can be produced by direct extraction from their respective flowers. In reality, this makes it difficult for production to meet demand, so companies use benzyl acetate, a major aromatic component of the two fragrances that is chemically synthesized from raw materials derived from petroleum.
On February 26, a KAIST research team led by Research Professor Kyeong Rok Choi from the BioProcess Engineering Research Center and Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering revealed the development of the first microbial process to effectively produce benzyl acetate, an industrially useful compound, from renewable carbon sources such as glucose. The results were published in their paper titled “A microbial process for the production of benzyl acetate”.
< Figure 1. Production of benzyl acetate through co-culture of upstream and downstream strains harboring the benzoic acid-dependent pathway. >
The team, led by Distinguished Professor Lee, aimed to produce benzyl acetate through an environmentally friendly and sustainable method, and developed an Escherichia coli strand to convert glucose into benzyl acetate through system metabolic engineering*.
*System metabolic engineering: a field of research founded by Distinguished Professor Lee to effectively develop microbial cell plants, a core component of the bio-industry that will replace the existing chemical industry, which is highly dependent on petroleum.
The research team developed a metabolic pathway that biosynthesizes benzyl acetate from benzoic acid derived from glucose, and successfully produced benzyl acetate by co-culturing** the strain.
**co-culture: simultaneously synthesizing two or more types of microorganisms in a mixture
However, it has been confirmed that the enzyme used to convert benzoic acid into benzyl acetate in this co-culturing technique acts non-specifically on an intermediate product during benzoic acid biosynthesis, producing a by-product called cinnamyl acetate. This process consumes the intermediate product needed for benzoic acid biosynthesis, thereby reducing the production efficiency of the target compound, benzyl acetate.
To overcome this problem, Distinguished Professor Lee and his team devised a delayed co-culture method, where they first produced benzoic acid in the earlier stages of fermentation by only culturing the top strain that produces benzoic acid from glucose, and later inoculated the bottom strain to convert the accumulated benzoic acid in the culture medium into benzyl acetate.
By applying this co-culture technique, the team suppressed the formation of by-products without further strain improvement or applying additional enzymes, and multiplied the concentration of the target compound by 10 times, producing 2.2 g/L of benzyl acetate. In addition, the team confirmed its potential for the commercial production of benzyl acetate through a technical economic analysis on this microbial process.
< Figure 2. Delayed co-culture of the Bn1 and Bn-BnAc3 strains for improved production of benzyl acetate through the benzoic acid-independent pathway.>
Research Professor Keyong Rok Choi, who was the first author of this paper, said, “This work is significant in that we have developed an effective microbial process to produce the industrially useful compound benzyl acetate, and also in that we have suggested a new approach to overcome the target chemical efficiency diminution and by-product formation issues caused commonly through non-specific enzyme activities during metabolic engineering.”
Distinguished Professor Lee said, “If we can increase the variety and number of microbial processes that produce useful chemicals through sustainable methods and at the same time develop effective strategies to solve chronic and inevitable problems that arise during microbial strain development, we will be able to accelerate the transition from the petrochemical industry into the eco-friendly and sustainable bio-industry.
This work was published online in Nature Chemical Engineering, issued by Nature.
This research was supported by the ‘Implementation of Intelligent Cell Factory Technology (PI: Distinguished Professor Sang Yup Lee) Project by the Ministry of Science and ICT, and the ‘Development of Protein Production Technology from Inorganic Substances through Microbiological Metabolic System Control’ (PI: Research Professor Kyeong Rok Choi) by the Agricultural Microbiological Project Group at the Rural Development Administration.
2024.03.05 View 7430 -
VP Sang Yup Lee Receives Honorary Doctorate from DTU
Vice President for Research, Distinguished Professor Sang Yup Lee at the Department of Chemical & Biomolecular Engineering, was awarded an honorary doctorate from the Technical University of Denmark (DTU) during the DTU Commemoration Day 2022 on April 29. The event drew distinguished guests, students, and faculty including HRH The Crown Prince Frederik Andre Henrik Christian and DTU President Anders Bjarklev.
Professor Lee was recognized for his exceptional scholarship in the field of systems metabolic engineering, which led to the development of microcell factories capable of producing a wide range of fuels, chemicals, materials, and natural compounds, many for the first time.
Professor Lee said in his acceptance speech that KAIST’s continued partnership with DTU in the field of biotechnology will lead to significant contributions in the global efforts to respond to climate change and promote green growth.
DTU CPO and CSO Dina Petronovic Nielson, who heads DTU Biosustain, also lauded Professor Lee saying, “It is not only a great honor for Professor Lee to be induced at DTU but also great honor for DTU to have him.”
Professor Lee also gave commemorative lectures at DTU Biosustain in Lingby and the Bio Innovation Research Institute at the Novo Nordisk Foundation in Copenhagen while in Denmark.
DTU, one of the leading science and technology universities in Europe, has been awarding honorary doctorates since 1921, including to Nobel laureate in chemistry Professor Frances Arnold at Caltech. Professor Lee is the first Korean to receive an honorary doctorate from DTU.
2022.05.03 View 11996 -
Professor Jay H. Lee to receive the 2013 AIChE CAST Computing in Chemical Engineering Award
Professor Jay H. Lee of Chemical and Biomolecular Engineering Department at KAIST has won the 2013 Computing in Chemical Engineering Award of AIChE"s CAST Division (AIChE, American Institute of Chemical Engineers and CAST, Computing & Systems Technology Division).
The CAST Computing in Chemical Engineering Award, sponsored by The Dow Chemical Company, is annually given to an individual who has made outstanding contributions in the application of computing and systems technology to chemical engineering.Professor Lee has been recognized for his pioneering research contributions for “novel paradigms for much improved and robust model predictive control in industrial processes.” He is currently the Head of Chemical and Biomolecular Engineering Department and Director of Brain Korea (BK) 21 Program at the department. BK21 is the Korean government’s initiative to support the growth of research universities in the nation and foster highly trained master’s and doctoral students as well as researchers.
The CAST Computing in Chemical Engineering Award will be presented to Professor Jay H. Lee at the CAST Division dinner to be held at the AIChE Annual Meeting this November in San Francisco, where he will also deliver the after dinner lecture associated with this award.
2013.06.12 View 11865 -
Distinguished Professor Sang-Yup Lee received 2013 Amgen Biochemical Engineering Award
- Previous award winners are world-renowned scholars of biochemical engineering including James Bailey, Michael Shuler and Daniel Wang
KAIST Chemical and Biomolecular Engineering Department’s Professor Sang-Yup Lee has been selected to receive the 2013 Amgen Biochemical Engineering Award. The award ceremony will take place this June at the International Biochemical and Molecular Engineering conference in Beijing, China.
The Amgen Biochemical Engineering Award was established by Amgen, a world renowned American pharmaceutical company, in 1993. Amgen awards leading biochemical engineers every two years. The first Amgen award recipient was James Bailey of the California Institute of Technology (Caltech) in 1993. Since then leading engineers that are sometimes called “founding fathers of biochemical engineering” have received the award including MIT Professor Daniel Wang and Michael Shuler of Cornell University.
The first nine award winners were Americans and in 2011 Jens Nielson of Chalmers University of Technology, Sweden, received the Amgen award as a non-American. Professor Sang-Yup Lee is the first Asian to receive the award.
The Amgen award panel said, “Professor Lee made an incredible contribution to the fields of synthetic biology and industrial bioengineering by finding chemical material, fuel, protein and drug production and system bioengineering through metabolic engineering of microorganisms.”
Professor Lee is an expert in metabolic engineering of microorganisms and contributed to the development of system metabolic engineering and system bioengineering. Furthermore, he developed various medical and chemical products and processes which were then applied to synthesise strains of succinate, plastics, butanol and nylon.
Professor Lee is a fellow of the Korean Academy of Science and Technology and National Academy Engineering of Korea; an international member of National Academy of Engineering (US); a former fellow of the American Association for the Advancement of Science; a member of the American Institute of Chemical Engineers, the American Industrial Microbiology Society and American Academy of Microbiology. He is currently Head of Global Agenda Council on Biotechnology and is world renowned for his work in biotechnology field.
2013.04.30 View 9908 -
KAIST Holds Symposium on Metabolic Engineering
The KAIST Institute for Bio-Century held a symposium on metabolic engineering at the auditorium of the KAIST"s Applied Engineering Bldg. on Thursday, Feb. 14, in cooperation with the BK21 Chemical Engineering Research Team.
The symposium focused on researches on bio-refinery program and bio-energy production in connection with steep hikes in oil prices and worsening environmental problems, including global warming.
Seven Korean experts presented their views on metabolic engineering strategies to effectively produce bio-energy and biofuel and the latest research trends.
Among the speakers, Prof. Lee Sang-yup, co-head of the KAIST Institute for Bio-Century, spoke on the theme of "Metabolic Engineering for Bio-refinery and Bio-energy.
The symposium provided an opportunity to take a glimpse into the latest research trends of metabolic engineering technology. Metabolic engineering technology is crucial to producing chemicals, energy and other substances from renewable biomass materials in a departure from heavy reliance on crude oil.
2008.02.14 View 16432 -
Professor Yang Named Recipient of Dupont Science & Technology Award
Professor Yang Named Recipient of Dupont Science & Technology Award
- Named as the recipient of Dupont Science & Technology Award of 2007- In recognition of his development of optical?bio-functional photonic crystal structures through Self-assembly of nanoparticles
Seung-Man Yang, a professor of Chemical and Biomolecular Engineering of KAIST (President Nam Pyo Suh) and the president of the National Creative Research Initiatives Center for Photon and Fluid Integrated Circuit by the Ministry of Science and Technology, has been named as the recipient of Dupont Science & Technology Award.
Dupont Korea, associate of Dupont, a world-class science firm, has established and conferred ‘Dupont Science & Technology Award’ since 2002 to promote basic sciences and industrial development of Korea. Dupont Science & Technology Awards are awarded to scientists of universities or state-run institutes who have made outstanding R&D achievements in the fields of Chemistry, Chemical Engineering, Material Science and Material Engineering within five years. Dupont Korea announced on May 2, 2007 that Professor Yang is the recipient of the award this year, following the strict examination by the Koran Academy of Science and Technology (KAST).
The reason for the award is Professor Yang’s development of prototype optical?bio-functional photonic crystal structures that can process a huge amount of data, resulting from a study that has discovered the principle of Self-assembly where multifunctional nanoparticles are manufactured and assembled for themselves.
Professor Yang’s recent research result about photon structures and nano patterns was published by Nature (February 2, 2006 edition); posted on Heart-Cut, the portal site of the American Chemistry Society (ACS), as highlight paper two times (November 4, 2002 and May 1, 2006); and introduced at Research/Researcher of MRS Bulletin by the U.S. Material Research Society (MRS) as main paper in December 2003. Professor Yang is very famous in Korea and abroad for the excellences of his research achievements and has made request seminars at Harvard University, University of Wisconsin, Caltech, University of California, etc. He is also invited speaker and session organizer of the MRS and the SPIE.
2007.05.08 View 21876