Exergy-Based Crossover Salt Tank Protection

A Study on Safeguards for Critical CSP Components

Abstract

In recent decades, renewable energy's share in global energy production has grown, with ambitious goals set for the green transition. Concentrating Solar Power (CSP) is crucial in this shift due to its energy storage and on-demand delivery capabilities, which prevent competition with intermittent sources like wind and photovoltaic (PV) systems. CSP enhances grid stability by providing energy during low production times and storing excess energy as heat. This stored heat, at high temperatures up to 550°C, can be used in industrial processes, including green fuel synthesis. The key components in CSP systems are the salt tanks, which are vulnerable to issues like corrosion, thermal shock, and thermal deformation, as seen in several projects worldwide. These issues are often due to temperature gradients in the tanks, which can cause buckling and fatigue rupture. The study focuses on strategies to minimize these risks, particularly through innovations in Vast's CSP v3.0 design. This includes a modular solar field arrangement to reduce temperature peaks and drops, active control of molten salt flow to match heat carrier fluid (HTF) temperatures, and a robust heat exchanger to buffer temperature changes. An innovative algorithm in the valve system at the molten salt tank inlets further enhances safety by directing hot salt to appropriate destinations, addressing the temperature differential issue that could reduce the equipment lifespan. This study, based on a numerical model of the entire plant and real weather data, tested various configurations to optimize the salt tanks' working conditions.