In the quest to make concentrated solar power (CSP) more efficient and commercially viable, researchers are turning to innovative technologies like particle-based systems and advanced heat exchangers. A recent study led by Christopher Bowen of Sandia National Laboratories has taken a significant step forward in understanding the longevity of these critical components, offering insights that could accelerate the adoption of next-generation CSP technologies.
The study, presented at the SolarPACES Conference Proceedings—translated to English as the Solar Power and Chemical Energy Systems Conference Proceedings—focuses on Generation 3 particle-sCO2 heat exchangers. These heat exchangers are pivotal in next-generation CSP plants, where they transfer heat from solar-energy-heated particles to supercritical carbon dioxide (sCO2), a fluid that can efficiently drive turbines to produce electricity. However, the commercial viability of these systems hinges on their durability and reliability over long operational periods.
Bowen and his team tackled this challenge by performing a sensitivity analysis to identify which variables most significantly impact the lifetime of these heat exchangers. They developed a reduced-order model of a hypothetical 16.7 MW commercial-scale particle-sCO2 heat exchanger made of IN617, a nickel-chromium-cobalt-molybdenum alloy known for its high-temperature strength. This defeatured model, as they call it, accurately predicts thermal performance and mechanical lifetime at a fraction of the computational cost of a fully featured model. “The reduced-order model allows us to analyze commercial-scale systems more efficiently,” Bowen explained, “which is crucial for making informed decisions about design and operation.”
To assess the impact of various input variables, the team used a Latin Hypercube Sampling method to simulate up to 128 different realizations of the heat exchanger under nominal operating conditions. They then analyzed the transient stress results to predict the number of cycles to failure due to fatigue and creep—two primary modes of failure in high-temperature applications. The results were striking: the uncertainty in the creep cycles to rupture data dominated the variation in lifetime predictions.
This finding is particularly significant for the energy sector. “Understanding the dominant factors affecting heat exchanger lifetime allows us to focus our efforts on improving those areas,” Bowen noted. “This could lead to more robust designs and better performance guarantees for commercial systems.”
The implications of this research extend beyond CSP. The methodologies and insights gained could be applied to other high-temperature energy systems, such as advanced nuclear reactors and fossil fuel plants. By improving the reliability and longevity of heat exchangers, these technologies could become more competitive in the energy market, contributing to a more sustainable and diverse energy mix.
As the energy sector continues to evolve, research like Bowen’s provides a roadmap for overcoming technical challenges and unlocking the full potential of innovative technologies. The journey toward a cleaner, more efficient energy future is complex, but with each breakthrough, the path becomes clearer.