PI: Sudhakar Neti
Co-PI(s): Clay Naito, Nasser Vahedi
University: Lehigh University

Thermal Energy Storage (TES) offers a critical solution to compensate for the intermittent nature of concentrating solar energy. TES can also contribute to improving the flexibility of existing fossil power plants, which are currently faced with cycling dispatching, due to the penetration of renewable power. Concrete and cementitious materials are promising candidates for sensible heat thermal energy storage at large scale and high storage temperatures. One of the drawbacks of concrete is its inherent low energy storage density which results in more required storage material, especially in large bulk storage systems. Integration of phase change material (PCM) within concrete is an innovative solution to address this shortcoming and make the storage system more efficient and compact.

At Lehigh University, a team of faculty, researchers and students are engaged in state-of-the-art research in the area of TES. This includes research in sensible, latent, and thermochemical energy storage. The group aims at developing a center for high-temperature TES at Lehigh. As part of these activities, members of the Energy Research Center (ERC) have joined efforts with faculty from the Advanced Technology Large Structural Systems (ATLSS) Center in a large project that aims at developing an integrated concrete-thermosyphons solution for the application of coal-fired power plants. This project is funded by the US Department of Energy (DOE).

The scope of work in this project involves engineering cementitious materials to improve its thermal characteristics and interfacing them with two-phase heat transfer devices, embedded in the concrete matrix. This proposed project is for a concept in which PCM is directly embedded into the concrete matrix, making it an integrated solution for TES. The proposed research will include screening potential PCMs for high temperature applications (300-600 deg. C), while considering their compatibility with concrete, material selection/preparation, integration method evaluation, such as micro or macro encapsulation, graphite foam infusion, or pellet insertion.

The scope of work will also include an analysis of PCM integration on concrete physical properties, and a study of cyclic performance and thermal stability of the integrated solution under multiple storage cycles. The topic and project objectives are in line with Pennsylvania Infrastructure Technology Alliance's (PITA's) goals and objectives; additionally, the project will enhance the technical capabilities of Lehigh University in this topic area.

This area of research has great potential for commercial applications in the solar industry and power generation plants. The proposed project will include cost share from the current DOE grant using concrete for sensible storage at large scale. As it will be set-up, the results of the proposed study would be available for direct application in that DOE project.