SBIR-STTR Award

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is to significantly lower the cost and expand the number of addressable markets for ice thermal energy storage. Cost effectively storing energy is imperative to a sustainable future. Storage can provide reliable access to power from intermittent renewable sources, increase the resiliency of the grid to weather events or terrorist attacks, and increase the utilization efficiency of existing assets, deferring costly upgrades. Today, ice thermal storage systems help building owners shift cooling loads from costly peak hours to when electricity is less expensive. Unfortunately the upfront cost of these systems, driven by the large cost of the cooling coil used to generate ice, prevents adoption from many users and has unduly restricted the number of addressable markets for ice thermal storage. Elimination of ice buildup on the cooling coil would reduce the size of the coil, and more importantly significantly lower the cost of these systems. Low-cost ice thermal energy storage could greatly improve the economics for long-duration energy storage technologies such as pumped thermal energy storage.This SBIR Phase I project proposes to translate the discovery of surfaces with zero ice adhesion into a cooling coil that can be integrated into a functioning ice thermal energy storage system. In order to repel ice, these surfaces require complete submersion in an immiscible oil phase, making coil geometry and overall system development challenging. At the beginning of this project, various plate and tube based cooling coil geometries will be systematically prototyped and refined, measuring the freezing and melting heat transfer efficiencies. Different formulations of the surface coating will be tested as well. The most promising candidate geometries will be charged and discharged over multiple cycles as part of an ice thermal energy storage system. The results from cycling will be compared to conventional ice-on-coil technology using metrics such as energy density and heat transfer efficiency. An ice shedding cooling coil, at less than a third of the size of an ice-on-coil system, is expected to deliver improved cooling performance. Demonstration of an ice shedding cooling coil in a functioning ice thermal energy storage system will prove the technology?s readiness to scale.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.

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.