Advanced Materials for SCP Molten Salt Storage-Heat Exchanger

Concentrating Solar Power utilizes molten salt thermal storage to enable 24 hour energy production and shift power production to times of less sunlight.Current molten salt operations use nitrate salts operating at 565°C.To improve performance, efficiency, and cost effectiveness switching to mixed chloride salts operating from 350-800°C is required. Increasing salt operating temperatures can reduce thermal energy storage system cost by up to 50% and improve efficiency by 23%. New materials are required to achieve 30 year life in thermal energy storage systems, including heat exchangers and storage tanks.This project will produce and qualify high and low thermal conductivity metallic composite materials with <20 micron/year corrosion rates suitable for fabrication of thermal energy storage tanks and heat exchangers. By changing fillers in a demonstrated, negligible erosion proprietary alloy matrix, high or low thermal conductivity can be achieved in a structural metallic material that can solve the major limitation of high temperature molten salt energy storage systems. Hybrimet™ high conductivity alloy composites will be fabricated and subjected to molten salt and scCO2 corrosion studies at the University of Wisconsin-Madison to verify corrosion resistance and creep testing at Brayton Energy. Attachment and joining processes suitable for construction of plate heat exchangers will be demonstrated. Preliminary designs and cost studies for heat exchangers will be evaluated, and prototype HX core manufactured. Overall, a multi-disciplinary efforts will design and fabricate a new high temperature heat exchanger capable of reliable operation in molten salt and super critical CO2 for +25,000 hours. Enabling 30 year life 750°C thermal energy storage systems enables DOE concentrating solar power goals to be met, increasing the use of renewable energy. Molten salt storage systems for grid leveling can be significantly more cost-effective and energy efficient than battery and other storage systems, and is scalable to MW and even GW scales.