Session: 18-02 HelioCon Windload

Paper Number: 138260

138260 - Dynamic Wind Loading on Csp Collectors: Insights From Nrel’s Measurements in Operational Parabolic Trough and Heliostat Fields 

Abstract: 

The DOE Solar Energy Technologies Office (SETO) aims to reduce the costs of Concentrating Solar-thermal Power (CSP) energy production. The CSP collectors, including heliostats and parabolic trough types, constitute a significant portion of the total costs of a CSP plant. Enhancing the reliability and reducing costs of these collectors requires a comprehensive understanding of wind loading on the collectors, which is a critical factor influencing structural integrity and optical efficiency. Dynamic loads, generated by turbulent wind interactions with the collector structures, remain poorly understood due to deviations between real-world conditions and idealized wind tunnel tests or numerical simulations. In the past few years, NREL conducted comprehensive field campaigns to measure static and dynamic wind loading in operational settings. These measurements, combined with simulations, provide valuable insights to advance CSP collector design. 

Over 2 years, we measured the turbulent wind field along with structural loads in an operational parabolic trough plant. The combined high-resolution measurements allow us to study the interactions of wind, turbulence, and the trough field. The data from this campaign are available to the public (https://doi.org/10.25984/2001061). A similar measurement campaign is currently ongoing, intending to study a heliostat field of an operational power-tower plant. The findings of these campaigns show the impact of environmental conditions on dynamic wind loading. Notably, atmospheric turbulence, wind direction, and collector orientation significantly influence the extent of dynamic wind loading. In addition to atmospheric turbulence, under certain conditions, upwind collector structures generate turbulent flow structures resulting in fluctuating loads on downstream rows or collectors. In this case, power spectra of wind and load coefficients show a peak in the same frequency range. The dynamic loads induced on collectors can impact fatigue lifetime and optical efficiency. To better understand the transfer of wind fluctuations to structural loads, we employ aerodynamic and mechanic admittance functions. While traditionally applied in civil engineering, these spectral transfer functions have been recently used to study solar collectors. In this presentation, we will describe admittance functions for full-scale parabolic trough and heliostat collectors developed using our measurements made at operational CSP plants. Characterizing these admittance functions will highlight the role of incoming wind fluctuations, sun-tracking angles, and collector orientation, in altering these functions describing the structural response. Moreover, we compare our results to previously reported findings for heliostats. The conclusions derived from this study will greatly enhance the understanding of wind loading on CSP collectors and its implications for structural integrity and optical performance. 

Presenting Author: Brooke J. Stanislawski NREL

Presenting Author Biography: Brooke Stanislawski is a Research Scientist at the National Renewable Energy Laboratory in Computational Sciences. She studies wind energy, solar energy, and hybrids (wind and solar) using numerical simulations, specifically focusing on wind loading, turbulence, fluid mechanics, optics, convective heat transfer, and atmospheric boundary layer flow. After working as a design engineer at Siemens Energy, she earned her Ph.D. at University of Utah where she developed expertise in flow modeling of the physical interactions between large solar photovoltaic plants and atmospheric flow.

Authors:

Ulrike Egerer NREL
Shashank Yellapantula NREL
Brooke Stanislawski NREL
Geng Xia NREL
Scott Dana NREL
David Jager NREL