Structure Design of Polymer-Based Films for Passive Daytime Radiative Cooling

Abstract

Passive daytime radiative cooling (PDRC), a cooling method that needs no additional energy, has become increasingly popular in recent years. The combination of disordered media and polymeric photonics will hopefully lead to the large-scale fabrication of high-performance PDRC devices. This work aims to study two typical PDRC structures, the randomly distributed silica particle (RDSP) structure and the porous structure, and systematically investigates the effects of structural parameters (diameter D, volume fraction fv, and thickness t) on the radiative properties of the common plastic materials. Through the assistance of the metal-reflective layer, the daytime cooling power Pnet of the RDSP structures is slightly higher than that of the porous structures. Without the metal-reflective layer, the porous PC films can still achieve good PDRC performance with Pnet of 86 W/m2. Furthermore, the effective thermal conductivity of different structures was evaluated. The single-layer porous structure with optimally designed architecture can achieve both good optical and insulating performance, and it is the structure with the most potential in PDRC applications . The results can provide guidelines for designing high-performance radiative cooling films.

Enhancing PV Efficiency through Scalable Radiant Cooling with Optimized Randomly Doped Particle Structures

“…In our previous studies [4] , the accuracy of combining Mie theory with the Monte Carlo method for calculating radiative transfer properties has been established. The model has been demonstrated to effectively determine the solar transmittance and infrared emissivity of RC films.…”

“…To accelerate the practical implementation of these emitters in PV, it is necessary to develop cost-effective, scalable solutions. One promising alternative is to use randomly doped particle structures, which are not only simpler to design but are also compatible with existing manufacturing technologies [4] . However, further investigation is needed to understand how microstructures affect the performance of these emitters.…”

Colourful phase change material-incorporated flexible film for efficient passive radiative cooling

“…Due to their high thermal emittance and low solar absorptivity, especially in the mid-infrared (MIR) range, cooling radiators achieve high cooling efficiencies, which reduces solar energy absorbed and enhances thermal energy transmitted through the ATW, allowing objects to remain cool during the day. Due to their environment-friendly operation and high thermal regulating efficiency, a wide variety of radiative coolers have been reported, such as white paintings [2-5], structural polymer films [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], textiles [22][23][24], multilayer photonic architectures [25][26][27] and metamaterials [28][29][30]. However, the required strong scattering of solar irradiance always induces broadband reflection, which limits the colour diversity and aesthetic applications of radiators.…”