Dynamic Radiative Cooling: Mechanisms, Strategies, and Applications for Smart Thermal Management

Abstract

As an emerging thermal management strategy, dynamic radiative cooling (DRC) technology enables dynamic modulation of spectral radiation properties under varying environmental conditions through the directional design of material spectral characteristics. However, a comprehensive review of the basic physical mechanisms of radiative heat transfer in DRC materials and various design principles involved in dynamic radiative thermal regulation is still lacking. This review systematically summarizes recent advances in this field, spanning from fundamental physical principles to intrinsic molecular and electronic mechanisms, and further to representative material systems and multi-band regulation strategies, highlighting the interdisciplinary research achievements and technological innovations. This work outlines the core mechanisms governing the regulation of different spectral bands during radiative heat transfer processes. Then, the main categories of DRC materials are systematically reviewed, including actively responsive structures, passively responsive structures, and multi-stimuli-responsive materials. Furthermore, the challenges faced by current DRC technology and future development trends are summarized and discussed, providing valuable reference and guidance for further research in this field. Although DRC technologies still face significant challenges in material stability, manufacturing processes, and system integration, the continuous advances in related areas and multifunctional materials are expected to broaden the application prospects of DRC in the future.

1. Introduction

The over-reliance on traditional fossil fuels has not only accelerated resource depletion but also exacerbated greenhouse gas emissions, leading to severe climate change [1, 2]. Temperature regulation in living and working environments has always been a critical aspect of human development. While technological advancements over the past centuries have introduced efficient and convenient methods for heating and cooling (such as gas heating and air conditioning), these energy-intensive devices have contributed significantly to the excessive consumption of fossil fuels and the associated greenhouse gas emissions [3, 4]. To address these urgent challenges, energy conservation, emission reduction, and the development of environmentally friendly technologies have become the focus in global research, resulting in the world facing unprecedented energy crisis and environmental pressure [5]. In a pathway aligned with the IEA’s scenario for achieving net-zero energy sector emissions by 2050, accelerating energy efficiency improvements can deliver over 70% of the projected decline in oil demand [6].

Passive radiative cooling (PRC) technology has garnered increasing attention due to its distinctive capability to achieve temperature reduction without external energy input, relying solely on radiative heat transfer [20]. This passive and sustainable mechanism plays a pivotal role in energy utilization, thermal regulation, and sustainable development. At typical ambient temperatures (~25–30 °C), the peak wavelength of thermal emission is consistent with the wavelength range of the atmospheric transparent window (ATW, 8–13 µm). This spectral overlap enables terrestrial objects to radiate heat directly into the cold outer deep space (~3 K) beyond earth’s atmosphere for radiative heat exchange [21]. As shown in Fig. 1, the evolution of PRC technology can be summarized by the following time points: In 1828, Arago published the first scientific discussion on the phenomenon of PRC in a publication [22]. During the 1970s and 1980s, researchers began to explore the practical designs for PRC. With the advancement of materials science, early selective PRC materials, including polymer and metal-based coatings, laying the groundwork for efficient radiative exchange within the ATW [23]. In 1981, Ge et al. [24] calculated the cooling power of three differen