An Optics-Based Approach to Thermal Management of Photovoltaics: Selective-Spectral and Radiative Cooling

TL;DR

This paper proposes optical modifications to solar modules, such as selective spectral and radiative cooling, to passively reduce self-heating, thereby improving efficiency and extending lifespan of photovoltaic systems.

Contribution

It introduces a novel design approach to minimize parasitic absorption and enhance thermal emission in PV modules using optical engineering techniques.

Findings

Cooling up to 10°C for one-sun modules

Cooling up to 20°C for low-concentrated modules

Potential for increased energy yield and reduced LCOE

Abstract

For commercial one-sun solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20 C - 30 C higher than the ambient. In the long term, extreme self-heating erodes efficiency and shortens lifetime, thereby dramatically reducing the total energy output. Therefore, it is critically important to develop effective and practical (and preferably passive) cooling methods to reduce operating temperature of PV modules. In this paper, we explore two fundamental (but often overlooked) origins of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical properties of the solar module to eliminate parasitic absorption (selective-spectral cooling) and enhance thermal emission (radiative cooling). Our Comprehensive opto-electro-thermal simulation shows that the proposed techniques would cool the one-sun and low-concentrated terrestrial solar modules up to 10 C and 20 C, respectively. This self-cooling would substantially extend the lifetime for solar modules, with The corresponding increase in energy yields and reduced LCOE.