The decarbonization of industrial heat sector, representing 74% of total industrial energy demand, is critical for combating climate change. Currently, only 9% of this demand is met by renewables, limited by their intermittent nature. An intermittent heating infrastructure lacking long-duration storage (> 24 hr) is unreliable, compromising energy security, especially in harsh Canadian winters. Concentrated Solar Thermal (CST) systems, storing solar energy directly as heat, offer promise. In a modular CST system, a field of mirrors concentrate solar energy into a well-insulated tank (receiver) filled with molten chloride salts. These salts absorb solar radiation, converting it to heat. Stored heat is then dispatched as steam via a heat exchanger system on demand. Though promising, these systems are in early development stages and require optimization before commercialization. This Future Energy Systems (FES) funded project will examine the governing physics of receivers operating above 950K and develop design guidelines for commercial scaling.