THERMAplus, Tunable TES for Different Applications and Climate Zones

Energy storage is required to address variability in supply and demand of electricity, while transitioning to a renewable-intensive grid, electrifying transportation, and electrifying heat. Buildings have high energy demands for heating, ventilation, and air conditioning (HVAC). Thermal Energy Storage (TES) can store off-peak/renewable-intensive for later use in heating or cooling the host building. TES brings both (a) major cost saving potential to chiller and heat pump systems, by shifting electrical loads to these lower cost periods, and (b) efficiency by capturing daily temperature swings and optimizing operating loads. TES significantly enables Grid-Interactive Efficient Buildings, which are essential for lowering costs, reducing carbon-intensity, and improving resiliency. In the SBIR Phase I project, we confirmed the performance of unique, tunable Phase Change Material (PCM) formulations. Tunability allows the storage temperature to vary seasonally, from summer to winter, and weekly to respond to different weather conditions. This tunability is a driving differentiator in our technology and has been identified as a priority area by the U.S. DEO to improve energy efficiency and increase the usable TES capacity compared to current non-tunable, fixed-point PCMS. In our Phase I project, we also evaluated optimization of TES by modeling, lab testing, and case studies for integrating TES into commercial buildings, campus, and district energy systems. The project team also evaluated PCM performance to ensure no degradation even after multiple cycles, and a high thermal density. The PCM can store both cooling and heating, in the same storage tanks using the same active material. The PCM tunability significantly reduces the energy (kWh) and power (kW) commercial customers require to heat and cool their buildings. The SBIR Phase II project will build upon the project team’s current product development and commercialization work, with a stretch target for installed cost of $40/kWh of thermal energy storage, and an essentially unlimited (>25 year) system life for a new high performance PCM which we are developing. TES has the potential to pair with additional energy technologies such as heat pumps, geothermal ground loops, solar thermal systems, fuel cells, combined heat & power, and district energy systems. TES is an important enabler to full decarbonization of buildings and is safer, more efficient, more durable and thus lower lifecycle cost, than lithium battery systems. The project will include system modeling and site demonstration of the TES hardware with innovative PCM and development of smart controls, using artificial intelligence (AI) and machine learning (ML).