A team of researchers from Texas A&M University has made a significant breakthrough in developing more straightforward thermal storage composite materials.

In a groundbreaking discovery, researchers appear to have found a way to design composite phase change materials that can store energy as heat. These innovative materials store heat (in this case, thermal energy) much like a battery stores electrical energy, and are made by combining materials that can store a lot of heat with metals that can move heat around quickly. Additionally, the researchers wanted to figure out how to make these materials store as much heat as possible, as quickly as possible, without making them too big or heavy.

  While storing energy in this way is nothing new, the composites' relatively simple design could open the door to use them in various applications, from heating buildings to powered cars. The design is such that it should be possible to make more efficient use of our energy resources. This could have significant implications for everything from how we heat and power our homes to designing energy-efficient vehicles.

Previous studies have explored the effectiveness of thermal energy storage systems, but none have provided insights on enhancing rate performance, optimizing, and predicting performance like the ones discovered by the team.

The study's researchers at Texas A&M University focused on the design of composite phase change materials that combine high-thermal conductivity metals to store thermal energy as latent heat. The goal was to create a material that strikes a balance between energy density and power density, allowing for efficient storage and quick charging without adding unnecessary weight or bulk. Essentially, the challenge was to develop a material that can store a lot of energy while also charging up quickly, much like an electric vehicle.

This research was funded by the Office of Naval Research, and the researchers managed to create a way to design these materials that take into account how hot the material will get, how much heat it can store based on its size, and how much heat it can store based on its weight. These are important factors when designing a material for a specific purpose, like storing heat for a certain application.

In essence, the team showed that by thinking of the system as an "effective composite," they could simplify the calculations and predict what the best structure would be. You can view one of the team's studies on the subject in the Wiley Online Library.

Study abstract:

"Phase-change materials (PCMs) and high-conductivity elements can be combined to form highly compact and efficient composite heat sinks. However, the design challenge presented by thermal composites composed of PCMs and high-conductivity elements remains unresolved. Herein, design guidelines are presented for radially varying cylindrical PCM composites. Numerical and analytical techniques are utilized to explore the utility and limits of optimal composite designs selecting for 1) temperature minimization, 2) specific effective heat capacity maximization, and 3) volumetric effective heat capacity maximization. Significant increases in each metric are observed when implementing radially variant designs in cylindrical geometries, especially for metrics of heat capacity. Furthermore, a hybrid approach to variant composite design is presented, allowing for the balancing of different design objectives. The utilization of a variable design under high heat flux (10 ± 1.4 W cm−2) and short melting periods (up to 50 s) is experimentally demonstrated, directly resulted in a 65% decrease in total system mass and a 200% increase in specific heat capacity while maintaining strong temperature dampening performance. In a second case study, a 23% decrease in mass is demonstrated while maintaining strong specific heat performance, emphasizing the broad utility of this approach."

References:

https://interestingengineering.com/innovation/new-efficient-thermal-storage-batteries