I-Corps: Translation Potential of Shape-stable Salogels for Low-Cost Thermal Batteries

Award ID: 2627675

This I-Corps project is based on the development of new class of thermal batteries to be used in residential heating, ventilation, and air conditioning (HVAC) units to reduce electricity costs and distribute peak loads of electricity consumption. Current electrification efforts, rising energy consumption, and a shift to intermittent energy sources have created an imbalance between power supply and demand. Thermal energy storage (TES) offers a solution to this imbalance by storing energy in the form of process heat (and cold) at a lower cost than electrochemical battery storage. However, integration of TES technology is currently limited by both a lack of chemically stable materials that store heat reversibly at temperatures relevant for HVAC systems (5 to 20 C), and the cost and complexity of current thermal batteries, primarily due to the complicated metal heat exchangers required to achieve sufficiently high heat storage rates. This technology is a new kind of hybrid thermal energy storage material consisting of finely tuned salt hydrate mixtures to enable a broad spectrum of materials that store/release heat reversibly. In addition, the shape stability of this material allows it to be molded into a desired shape and retain that shape in both the liquid and solid phases, allowing an interface with a refrigerant/heat transfer fluid, circumventing the need for metal heat exchangers within a thermal battery. This thermal battery technology may reduce electricity costs for homeowners while simultaneously alleviating stress on the electricity grid. This I-Corps project utilizes experiential learning coupled with first-hand investigation of the industry ecosystem to assess the translation potential of a shape-stable, phase-change material (PCM) to be used as a thermal battery in residential heating, ventilation, and air conditioning (HVAC) units to reduce electricity costs and distribute peak loads of electricity consumption. The technology is a new kind of hybrid thermal energy storage material consisting of cross-linked polymer networks that provide shape stability to salt hydrates (termed salogels). Salogels consist of finely tuned salt hydrate mixtures to enable a broad spectrum of materials that store/release heat reversibly through their phase transition over the relevant 5 to 20 C temperature range. This enables a broad selection of ideal materials, depending on the system and climate conditions. The shape stability of the salogel allows it to be molded into a desired shape and retain that shape in both the liquid and solid phases, allowing a quasi-direct interface with a refrigerant/heat transfer fluid, circumventing the need for metal heat exchangers within a thermal battery. This technology may help meet demand for long duration energy storage, strengthen domestic energy infrastructure, and support grid resilience during extreme weather events. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Program Director: Ruth Shuman