Owing to the stringent mitigation measures on fossil energy, solar energy has been explored for potential use in industrial processes. Besides, Concentrating Solar Technologies are a promising solution for clean and renewable production of electric energy for both domestic and industrial utility. Increasing the absorption temperature of heat transfer fluids has resulted in high-performing Concentrating Solar Technologies.
In a recent paper published in the Solar Energy journal, Dr. Jesús Gómez-Hernández, Dr. Pedro González-Gómez, Dr. Javier Villa Briongos and Professor Domingo Santana from Universidad Carlos III de Madrid in Spain presented a new linear particle receiver located at the ground. This novel receiver uses air and particles as heat transfer fluid and linearly receives the concentrate solar energy from the top. Its feasibility was investigated by analyzing the air and particle temperatures as a function of the particle receiver geometries and solar field.
Briefly, the proposed receiver comprised of consecutively connected fluidized beds that allowed linear absorption of solar energy and horizontal movement of solids. A new solar field, for redirecting the concentrated solar energy to the receiver, was proposed and analyzed. Eventually, the overall performance of the receiver was validated by taking into consideration target bed temperatures of 200 °C, 400 °C, 600 °C, and 800 °C to respectively reproduce Concentrating Solar Technology integration of medium and high process temperature heat, Rankine Concentrating Solar Power, and supercritical CO2 cycles.
The approach is indeed cost-effective and does not require consecution of a central solar tower as the receiver is placed at the bottom level. The receiver design allowed for efficient horizontal movement of the particles attributed to the fluid-like behavior of the particles and fluidized air particles. The beam-down linear Fresnel reflector (BDLFR) solar field based on the Fresdemo Fresnel design was used to simplify the analysis. The influence of the eccentricity and receiver width on the average flux intensity was investigated. Results showed that flat reflectors exhibited low average flux intensity on the ground receiver and could as well be neglected. For curved primary reflectors, low eccentricity resulted in the highest incident power and low solar field efficiency of 19.6 kW/m2 and 13.6 % respectively for 0.1 m receiver width. Additionally, increasing receiver width and eccentricity exhibited higher solar field efficiency.
In summary, the Spanish study successfully reported a novel particle receiver for Concentrating Solar Technology, and its performance studied for different widths, lengths, and sand masses for different bed temperatures. The results illustrated the optimization of design to maximize heat gained by particle flows and air thus demonstrating the importance of analyzing the configuration of both particle receiver and optic system for individual industrial processes. For instance, a solar field efficiency of 40.25 % and receiver thermal efficiency of 80 % was obtained by heating a sand mass flow of 1.75 kg/s in a receiver of 0.8 m secondary eccentricity and 0.5 m width up to 600 °C in a length of 280 m. The study presents useful insights that will pave way for design of high-performance solar receivers for industrial applications.
Gómez-Hernández, J., González-Gómez, P., Briongos, J., & Santana, D. (2020). Technical feasibility analysis of a linear particle solar receiver. Solar Energy, 195, 102-113.