Reducing energy use in buildings is often approached through new control systems or higher-efficiency heating and cooling equipment. A recent materials study suggests another route: embedding thermal energy storage directly into building components. Mechanical engineers at the University of Texas at Dallas, working with national laboratory and university partners, have developed a wood-based composite that can absorb, store, and release heat without requiring electricity.
The work is led by Shuang (Cynthia) Cui, an assistant professor of mechanical engineering, and focuses on a class of materials known as phase-change materials. These substances absorb heat as they melt and release it as they solidify, making them useful for moderating temperature swings. In buildings, this behavior could help reduce peak cooling and heating demands by passively storing excess thermal energy.
Foster, K. E. O., Magalindan, B., Perruci, G. F., Li, Y., Zheng, Q., Lynch, K., Srubar, W. v., Chen, X., Booten, C., Lu, H., & Cui, S. (2025). Wood template-supported phase change material composites for durable and form-stable thermal energy storage in buildings. Materials Today Energy, 54, 102120. https://doi.org/10.1016/j.mtener.2025.102120
Phase-change materials have been studied for years, but their use in construction has been limited by practical issues. When these materials melt, they can leak, and encapsulating them in rigid containers often reduces their effectiveness. The UT Dallas team addressed this problem by using wood as both a structural template and a functional component of the composite.
Shuang (Cynthia) Cui from University of Texas at Dallas stated,
“Working with our national lab partners gave me invaluable experience and opened important doors, demonstrating how interdisciplinary teams can turn sustainable materials into real-world solutions.”
The researchers began by removing lignin from natural wood, leaving behind a porous, sponge-like structure. This process preserves the wood’s internal channels while creating space to host other materials. The pores were then filled with a phase-change compound blended with a soft polymer that solidifies into a flexible plastic. The polymer prevents leakage during melting while also reinforcing the wood structure.
Laboratory testing showed that the resulting composite could undergo more than 1,000 heating and cooling cycles without mechanical failure or material loss. Unlike many thermal storage materials that trade strength for functionality, this composite maintained structural integrity while repeatedly absorbing and releasing heat. According to the research team, this balance between mechanical durability and thermal performance is critical for long-term use in buildings.
The material is designed to act as a thermal buffer. In warm conditions, it absorbs heat entering from outside, slowing the rise of indoor temperatures. When temperatures drop, the stored heat is gradually released back into the space. In principle, wall panels, flooring, or ceiling elements made with this composite could reduce reliance on air conditioning and space heating, particularly during daily temperature fluctuations.
Thermal energy storage in buildings is gaining attention as a way to manage energy demand more efficiently. By shifting heating and cooling loads over time, such materials can help smooth peak electricity use and complement renewable energy sources. The wood-based approach also aligns with broader interest in using renewable and bio-derived materials in construction.
The study is the result of collaboration across multiple institutions, including national laboratories and other universities with expertise in materials science and energy systems. Researchers involved note that interdisciplinary work was essential, combining knowledge of mechanical behavior, heat transfer, and material processing.
While the current results are based on laboratory-scale samples, the team is continuing to refine the material and explore pathways toward commercialization. Future work will focus on optimizing thermal capacity, improving manufacturing processes, and evaluating performance under real building conditions.
If successfully scaled, the composite could offer a passive, low-energy method for improving indoor comfort. Rather than replacing existing systems, materials like this are intended to work alongside conventional heating and cooling technologies, reducing their operating time and overall energy consumption. For engineers working at the intersection of materials and energy efficiency, the study highlights how structural materials themselves can play an active role in managing heat.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
