As the planet warms, keeping cool without releasing greenhouse gases is a major challenge, but radiative cooling technology is poised to meet this goal. Radiative cooling functions by simultaneously reflecting most of the sunlight and sending infrared thermal radiation through the atmosphere to the cold universe. As a promising cooling strategy without energy consumption, it has been attracted in both academia and industry recently. In order to provide engineers with guidelines for selecting the best materials for commercializing this technology and enable researchers to propel this technology forward through improved material designs, the modeling and analysis of radiative cooling are essential. Based on this background, this thesis aims to advance our fundamental understanding of radiative cooling technology and then propose a general approach for designing potential radiative cooling materials. A novel radiative cooling material was designed and fabricated accordingly. Then an assessment method was proposed to compare the performance of the developed radiative cooling material with that of the existing materials. In addition, a method to couple the spectral-dependent radiative cooling with the building energy simulation program EnergyPlus was developed to assess the impacts of the developed radiative cooling material on building energy consumption.Firstly, a general approach for the design and optimization of potential radiative cooling materials was proposed. The information of radiative cooling materials reported in the literature was gathered and grouped into four categories: multilayer structure, metamaterial, randomly distributed particle structure, and porous structure. Based on the database, the approach of selecting appropriate materials and corresponding simulation methods was summarized. The proposed design approach makes it possible for researchers to propel radiative cooling technology forward through improved material design in the future.According to the design approach, a novel radiative cooling material was then designed. Glass bubbles have been proposed as a component of high-performance radiative cooling paints because of the bubbles’ controllable size and their enhancement of light scattering. However, the current radiative cooling paints with glass bubbles suffer from low solar reflectivity because of their large particle size. In this study, we proposed the idea of breaking the glass bubbles by means of ball milling to enhance the cooling performance of radiative cooling paints. The ball-milling process increased the solar reflectivity from 93.3% to 97.3% with the thermal emissivity of ~93.4%, while the temperature difference with the ambient air was increased from 1.8 °C to 3.5 °C at noon. When the paint was covered with nanoporous polyethylene film, the temperature was 8.5 oC below the ambient air temperature at noon and 14.1°C at night. The superior radiative cooling capability of the paint and the record-setting temperature difference achieved in Hong Kong demonstrated its excellent cooling performance, while the simple preparation method and ease of application make this paint promising for commercialization and large-scale production.To facilitate the applications of the developed radiative cooling material, it is important to compare its performance with the existing materials. However, there has not been an effective method for comparing the cooling performance of the materials tested in different geographical locations and laboratories. In order to tackle this problem, a simulation-based method for comparing the cooling performance of different radiative cooling materials was presented. It consists of the basic radiation theory, the standard solar spectrum, and six standard model atmospheres. The proposed simulation-based comparison method was then used to compare the developed radiative cooling paint with the 55 radiative cooling materials reported in the literature. The results show that the developed radiative cooling paint was among the best in terms of cooling performance.Practical applications of the developed radiative cooling paint in buildings are expected to reduce the energy consumption for air-conditioning. To quantitatively and accurately assess the impact of radiative cooling material on building energy consumption, a method to couple the spectral-dependent radiative cooling with the building energy simulation program EnergyPlus was developed. Compared with the existing constant-emissivity model, the proposed coupled model can further consider the influence of spectral-dependent emissivity, material surface temperature, and precipitable water on the radiative cooling power in EnergyPlus. Based on the results in a typical strip mall in New York, the radiative cooling power calculated by the proposed spectral-dependent model can be significantly different from that by the existing constant-emissivity model. Therefore, the coupling of spectral-dependent radiative cooling with building energy simulation can improve the accuracy of energy performance assessment for buildings with radiative cooling technology. By using this model, it was found that the use of radiative cooling paint can significantly reduce the cooling energy consumption in strip malls in Shenzhen and Beijing.