Switchable Polarity Freeze Suppression for Distributed Thermal Energy Storage

Renewable energy deployment and the resulting load variability have amplified the need for advanced systems that provide increased energy dispatchability. Additionally, the high operating cost, low efficiency, and high refrigerant leak rates are driving refrigeration equipment research and development. Currently, these two issues are being addressed independently by work focusing on stand-alone energy storage and natural refrigerant vapor compression systems, respectively. The overlap of these two problems creates a massive opportunity for energy savings and lower cost energy storage. Over the course of a year, 4.5% of the US installed generation capacity provides refrigeration to commercial and residential customers, representing more than 400TWh of consumption that contributes disproportionately to peak demand. Unfortunately, no refrigeration technology has been proposed to simultaneously provide distributed energy storage and increase energy efficiency. This Small Business Innovation Research Phase I project will investigate Switchable Polarity Solvents as refrigerants in Freeze Point Suppressant FPS) heat pumps, a recently developed refrigeration architecture that uses storable, water-based refrigerants. FPS heat pumps decrease primary energy consumption through waste heat utilization while simultaneously converting refrigeration loads into distributed, behind-the-meter energy storage. By controlling refrigerant concentration, FPS heat pumps can meet thermal loads from 0 to -35C. Given this range, FPS heat pumps, if deployed in the US on a large scale, have the potential of saving 80TWh of electricity annually while providing 270GW of energy storage infrastructure. Rebound has conducted business model investigations and determined supermarkets to be the best go-to- market sector. Implementing SPS-based FPS cycles at just United States supermarket chains will produce the following impact: 50,000,000 tons of CO2 emissions avoided per year: Implementing SPS-based FPS cycles in just this single application has the same effect as removing 10 million cars from the road, roughly 4% of the entire US automotive fleet. 26 Terawatt-Hours of electricity saved per year: Reducing LT refrigeration loads by 40% amounts to enough savings to power 2.3 million American homes. 2.9 GW of low cost, high ROI energy storage: With a storage material cost roughly 80% lower than the cheapest batteries; SPS-based FPS cycles represent a dramatically simpler path to energy storage.