Session: 06-03: CSP Receivers and Reactors II

Paper Number: 156678

156678 - Optimizing Aperture-to-Receiver Area Ratios in Multi-Flow Falling Particle Receivers 

Abstract: 

High-temperature solar thermal technologies have emerged as a promising solution to meet the growing demands of global energy consumption. Concentrated solar power (CSP) effectively generates clean energy by using mirrors, called heliostats, to focus sunlight on a central receiver. Captured solar heat is transferred to a heat exchanger, which powers a turbine to generate electricity, offering a sustainable alternative to traditional energy sources. CSP designs use different heat transfer fluids, such as molten salts. However, the target temperature is above 700°C, which cannot be achieved using molten salts. Achieving target temperatures is attainable with falling particle receivers, which effectively harness and store solar heat using particles. These receivers generate a particle flow by releasing particles from the top, forming a curtain exposed to concentrated sunlight. This study focuses on the falling particle receiver due to its potential for higher efficiency and reduced maintenance requirements. Additionally, the CSP plant model in this research integrates supercritical CO₂ (sCO₂) power cycles, following recommendations from the National Renewable Energy Laboratory (NREL) roadmap, to further enhance energy conversion efficiency.

Our team has previously modeled a multi-flow particle receiver with multiple sections and optimized the mass flow rate (MFR) in each section. This study focuses on optimizing receiver size in relation to aperture dimensions and power input. A comprehensive parametric analysis of receiver dimensions was conducted, considering factors such as time of day and power input variations. Receiver size is essential for system efficiency and reducing heat loss, significantly enhancing performance in CSP systems. By optimizing receiver dimensions, we were able to thoroughly assess their effect on thermal efficiency, building on our earlier research on mass flow rate (MFR) optimization. The results show that adjusting the receiver size can greatly improve thermal efficiency because the dimensions affect heat loss and particle irradiation. Adjusting the receiver dimensions can enhance energy capture and reduce heat loss, resulting in better system efficiency. This study examines the relationship between nominal power output and receiver size, highlighting its significant impact on thermal efficiency. Achieving an optimal balance between high thermal efficiency, effective solar energy capture, and minimized heat losses is complex. A larger receiver area allows for greater solar radiation capture, enhancing potential energy yield. While the increase in surface area enhances heat transfer, it also leads to greater convective and radiative losses, potentially diminishing the overall thermal efficiency gained. Beyond a certain point, increasing the receiver size can increase the heat losses, outweighing the increased solar irradiation capture. This study emphasizes the critical need to identify the ideal receiver size that seamlessly integrates with MFR optimization, ultimately enhancing efficiency and reducing heat losses. Balancing these factors will contribute to the development of an efficient model with a cost-effective CSP system that aligns with the Department of Energy’s goal.

Presenting Author: Ahmed Mohamed The University of New Mexico

Presenting Author Biography: I am a PhD student and research assistant specializing in Concentrated Solar Power (CSP) systems, with a focus on advancing thermal efficiency and performance in multi-flow falling particle receivers. My research centers on optimizing design parameters, particularly aperture-to-receiver area ratios, to maximize energy capture and reduce thermal losses. Working closely with modeling approaches, I aim to contribute to the development of high-temperature CSP systems that can support the next generation of renewable energy solutions. Through my work, I seek to bridge theoretical advancements with practical applications, enabling CSP to play a vital role in sustainable energy production.