Session: 06-01: Thermal Energy Storage

Paper Number: 130856

130856 - Particle Handling in Particle-Based Pumped Thermal Energy Storage 

Abstract: 

The integration of renewable energy sources into the electric grid, aimed at reducing carbon emissions in industrial sectors, necessitates the implementation of energy storage solutions to ensure a reliable and continuous energy supply. Thermal energy storage (TES) emerges as a promising option, leveraging unique advantages in scale and siting flexibility, particularly to meet the demands of long-duration energy storage (LDES, ranging from 10 to 100 hours). Solid particles, identified as thermal storage media, present a unique prospect due to their low cost, capability to operate at high temperatures, and thermal stability. Beyond its integration with concentrating solar power (CSP) technology, this energy storage system demonstrates versatility by supporting wind and solar photovoltaics as a large-capacity electric-thermal battery.

A novel Pumped Thermal Electricity Storage (PTES) system utilizes low-cost solid particles as storage media which delivers several advantages. The system's round-trip efficiency is maximized through an increased temperature difference between hot and cold reservoirs. The high-temperature heat can generate power by a high-efficiency power cycles such as air-Braton cycle. For the charging/discharging process, a counterflow direct contact gas/particle pressured fluidized bed heat exchanger (PFB HX) has been strategically employed to achieve cost savings, a low-temperature approach, and high exergy. In comparison to PTES systems with liquid storage media, this developed system offers a simplified configuration and high economic capacity.

The PFB HX stands as a key component in the PTES system, facilitating efficient heat transfer between high-temperature storage media and working fluids. Recognizing its significance, fluidization characterization of the PFB HX becomes important for optimization and achieving targeted performance. A comprehensive hydrodynamic analysis of the fluidized bed has been conducted, optimizing key parameters such as pressure drop, air superficial velocity, minimum fluidization velocity, and fluidization regime at elevated temperatures. To ensure optimal fluidization conditions, a gas distributor has been designed and fabricated, mitigating the risk of unwanted fluidization phenomena like channeling and stagnation.

A laboratory-scale prototype of the PTES system with the PFB HX is currently under assembly, planned to undergo operational testing during the charging process to validate its anticipated performance. The experiment will involve measuring pressure drops and temperatures within the fluidized bed, providing empirical data to verify the predicted fluidization calculations including dense bed height. The testing at various elevated temperatures will lead to deep understanding in temperature dependent fluidization conditions and benefit heat transfer modeling. Heat transfer and thermal efficiency of the PFB HX will be experimentally analyzed and system optimization of PFB HX will be conducted with control of both particle and air flow rates to maximize heat transfer between two media. This iterative process ensures that the developed PTES system with PFB HX not only meets but exceeds the performance expectations, marking a significant stride in the advancement of efficient and sustainable energy storage technologies.

Presenting Author: Shin Young Jeong National Renewable Energy Laboratory

Presenting Author Biography: ShinYoung joined Thermal Energy System group at NREL as postdoctoral researcher in September 2023. He received his PhD in Georgia Institute of Technology with his research focus on granular flow and relevant heat transfer for CSP and TES applications. At NREL, he has participated in developing pressurized fluidized bed heat exchangers and light trapping cavity receivers for next-generation CSP technology.

Authors:

Shin Young Jeong National Renewable Energy Laboratory
Jason Hirschey National Renewable Energy Laboratory
Munjal Shah National Renewable Energy Laboratory
Jeffrey Gifford National Renewable Energy Laboratory
Janna Martinek National Renewable Energy Laboratory
Zhiwen Ma National Renewable Energy Laboratory