Radiative cooling capacity on Earth

TL;DR

This paper presents a comprehensive assessment of Earth's global radiative cooling capacity, using a new model validated against experimental data, to inform sustainable cooling technologies and environmental strategies.

Contribution

It introduces a precise assessment model for global radiative cooling capacity, accounting for geographic and environmental variations, and categorizes Earth's regions based on cooling potential.

Findings

Global RC capacity varies significantly across regions.

The model aligns well with experimental data.

Five key regions identified with distinct cooling potentials.

Abstract

By passively dissipating thermal emission into the ultracold deep space, radiative cooling (RC) is an environment-friendly means for gaining cooling capacity, paving a bright future for global energy saving and carbon dioxide reduction. However, assessing the global RC capacity at the day-to-annual scale remains challenging as the RC capacity significantly depends on geographic and environmental conditions. To our knowledge, no analysis of global RC capacity has been reported. Herein, we show the distribution of RC capacity on Earth by establishing a precise assessment model for evaluating the performance of a radiative cooler. Our assessment is comprehensively validated against experimental data and extended to elucidate the capacity of representative broadband and selective cooler. We also categorize the global RC capacity into five representative regions based on the year-round cooling power. Our assessment can inform trade-offs between design and practical application for the RC systems, alongside promoting RC-based technologies to tackle worldwide energy and environment challenges.