Enhancing thermal management in concentrated photovoltaic cells using supercritical carbon dioxide

Abstract

A key challenge for liquid-based cooling in concentrated photovoltaic systems is the significant rise in coolant temperature along the flow path, which degrades thermal performance and increases temperature non-uniformity. This study introduces supercritical carbon dioxide as a novel coolant for concentrated photovoltaic systems and compares its thermal performance with that of water under varying operating conditions. The cooling system incorporates a heat sink with four different channel sizes, assessed under medium, high, and ultrahigh concentration ratios. The results indicate that the supercritical carbon dioxide-based system outperforms the water-based system at medium concentration ratios, with greater benefits in smaller channels under high and ultrahigh concentration ratios. Furthermore, the hydraulic performance of the supercritical carbon dioxide-based system improves significantly in smaller channels. The supercritical carbon dioxide-based system lowers cell temperature and improves uniformity, reducing the maximum cell temperature by 4.3 K and temperature difference from 6.4 K to 2.6 K at high concentration ratios. At ultrahigh concentration ratios, smaller channels further enhance performance by increasing heat rejection per unit pumping power. In conclusion, considering the need for effective cooling at high and ultrahigh concentration ratios, along with uniform and reduced cell temperatures and low pumping power, replacing conventional liquid-based systems with supercritical carbon dioxide-based units offers notable efficiency advantages for next-generation concentrated photovoltaic systems.