Lightweight, Passive Radiative Cooling to Enhance Concentrating Photovoltaics

Radiative cooling can reject significantly more waste heat than convection and conduction at high temperatures by sending it directly into space. As a passive and compact cooling mechanism, radiative cooling is lightweight and does not consume energy. These qualities are promising for thermal management in outdoor systems generating low grade heat, such as concentrating photovoltaics (CPV) and thermophotovoltaics (TPV). In this work, we first simulate radiative cooling for a wide range of working conditions, including heat loads from 6 to 100 W with different CPV cooling designs. We then demonstrate a CPV system integrated with radiative coolers, achieving a 5°C to 36°C temperature drop and an 8% to 27% relative increase of open-circuit voltage for a GaSb solar cell, under a heat load of above 6 W with different cooling designs. We show that the temperature drops from radiative cooling may significantly improve CPV system lifetimes.