A Polarimetry-based Field-deployable Non-interruptive Mirror Soiling Detection Method

TL;DR

This paper introduces a rapid, non-intrusive, UAV-compatible polarimetric imaging method for large-area mirror soiling detection in CSP plants, improving speed and reducing operational disruptions.

Contribution

The novel PIMS technique combines polarimetric imaging with UAV deployment for efficient, large-scale, non-intrusive mirror soiling assessment, advancing current monitoring methods.

Findings

Effective correlation between DoLP and soiling levels established

Field deployment demonstrated rapid, large-area assessments

Minimal installation required for UAV-based operation

Abstract

The soiling level of heliostat mirrors in Concentrated Solar Power (CSP) fields is one of the key factors that significantly influences optical efficiency. State-of-the-art methods of monitoring heliostats soiling levels still face various challenges, including slow speed, labor-intensive operations, resolution and accuracy constraints or interruptions to solar field operations. We present a rapid, cost-effective, and non-intrusive method for mirror soiling detection based on polarimetric imaging, referred to as Polarimetric Imaging-based Mirror Soiling (PIMS). The compact PIMS device is designed for integration with unmanned aerial vehicles (UAVs), enabling rapid, large-area assessments of heliostat mirrors for efficient soiling detection. Our method utilizes the correlation between the Degree of Linear Polarization (DoLP) and surface soiling level based on Mie scattering theory and Monte Carlo simulations. Field deployment of the PIMS method requires minimal device installation, and its UAV-based operation allows for soiling detection without interrupting plant activities. The PIMS method holds the potential for mirror soiling detection across various concentrated solar power (CSP) plants and can be further adapted for other types of solar fields, such as parabolic trough systems.