Development and Testing of Low-Cost Sulfur Thermal Energy Storage Integrated with Combined, Cooling, Heat, and Power

The research team developed and validated the operation of a combined cooling, heating, and power plant integrated with novel sulfur thermal energy storage technology for adoption in commercial sectors. This technology uses low-cost molten sulfur as the storage fluid that can store and discharge heat efficiently. Element 16 adds flexibility to combined cooling, heating, and power plants by storing exhaust heat energy in sulfur thermal energy storage, and by allowing the production of electricity and steam to occur at different times. In areas of high renewable energy penetration, the thermal energy storage combined cooling, heating, and power system can be optimally designed and intelligently controlled to reduce peak demand charges and interact seamlessly with the grid to provide dispatchable power and essential services. 

The pilot integrated sulfur thermal energy storage and combined cooling, heating, and power system was setup and commissioned at Element 16’s facility in Arcadia, California. The measured average charge and discharge rates of the pilot sulfur thermal energy storage system were 12.6 kilowatts and 27.6 kilowatts respectively with a calculated thermal efficiency of 85.4 percent. A technoeconomic model was developed to determine the optimal sulfur thermal energy storage configuration for integration with combined cooling, heating, and power in a representative large commercial building located in Los Angeles with an average electricity and thermal energy requirement of 280 kilowatts and 206 kilowatts, respectively. An optimal sulfur thermal energy storage capacity ratio of 3.0 resulted in the minimum payback period of 8.7 years. The annual natural gas savings and emissions reductions for sulfur thermal energy storage capacity ratio ranging between 3.0 to 4.6 was estimated to be $7,320 to $9,015 and 34 tons to 42 tons of CO2 for the commercial building. 

This report includes a review of the technical performance and the successful pilot demonstration of sulfur thermal energy storage and combined cooling heat, and power thermal energy storage systems, and technology-to-market activities of the technology realizing more than $6 million in sulfur thermal energy storage research and development and commercialization funding since the beginning of this project