Design considerations for commercial scale particle-based thermal energy storage systems

Particle-based heat transfer materials used in concentrating solar power systems benefit from gravity-fed arrangements such as vertically integrated components inside the receiver tower which can eliminate the need for conveyance machinery. However, the amount of particles required for commercial scale systems near 100 MWe can require towers with very thick walls that must be built with high-strength concrete. Cost models for particle-based receiver towers with internal particle storage are being developed in this work and compared to well-established cost models that have been used to estimate tower costs for molten salt systems with external storage tanks. New cost models were developed to accommodate the high-temperature applications required for CSP. Further research is needed to directly compare costs between tower-integrated and external storage. For now, a method is proposed to superimpose increased storage costs with existing molten salt CSP towers. For instances where suitable materials are unavailable or do not meet the structural requirements, ground based storage bins must be used in concert with mechanical conveyance systems. Ground based storage vessels have been shown to be consistent with low thermal energy storage cost and heat loss goals. Ground based storage vessels are well-established in industry.