SBIR Phase II: Grid-scale electricity storage from waste heat

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is to unleash the potential of water as a thermal energy storage medium for building air conditioning. Today’s commercial ice storage systems, based on Ice-on-Coil (IOC) technology, fails to capture this potential because efficiently moving thermal energy into and out of water as it freezes and melts is challenging. The proposed Icephobic Heat Exchange (IHEX) technology eliminates the adhesion of freezing water to cold surfaces, preventing ice buildup on the coil and realizing the power of water for low-cost, high efficiency, resilient building cooling. IHEX based thermal storage removes the primary barriers to product adoption: high cost and spatial constraint limitations. It helps building owners lower their cooling costs, strengthen their cooling resiliency, and reduce their carbon emissions through affordable and spatially adaptable solutions. From a broader perspective, storing energy is imperative to a sustainable electric grid. Globally, an estimated potential for up to 2.8% of worldwide GHG emissions can be offset through full scale deployment of IHEX technology in building cooling. Beyond reliable access to power from intermittent renewable sources, cost-effective thermal storage can increase cooling resiliency by meeting cooling demand when the electric grid is down. This SBIR Phase II project proposes to catalyze development of IHEX technology by demonstrating high reliability for IHEX materials and establish high energy density, efficiency, and cooling resiliency for commercial-scale IHEX systems. IOC systems use miles of tubing to generate the necessary amount of surface area for heat transfer, which is costly and energy intensive, and their modular systems require significant space. This project will demonstrate that IHEX technology meets all the existing strengths of IOC technology, such as durability, while addressing potential economic concerns. First, materials testing will be completed after a year’s worth of freeze/melt cycling on a prototype-scale system to indicate long IHEX system life. Second, the ability to use customizable storage tanks with high energy density will be demonstrated. Customizable, space-filling tanks will help IHEX technology eliminate the physical space constraints that have thwarted so many commercial projects. Third, a commercial-scale IHEX system will be used to derive a 20% energy efficiency improvement compared to IOC solutions and a low, $28/ton-hr cost. And finally, by working with our product end-users and industry, a 67% reduction in total cost of ownership compared to conventional cooling systems will be shown. 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.