![]() ![]() Total Solar Reflectance (TSR) describes how much of the sun's energy an object reflects. Objects reflect or absorb solar energy from these three regions: UV, visible and infrared. Reflectivity and emissivity are the factors that can be manipulated. ![]() Convection is largely dependant on air flow, and conduction depends on how well an object is insulated to prevent heat flows. For most everyday objects, the heat emitted is found at much longer wavelengths and is dependant on an object's black body properties.įor an object in an outdoor environment, the four main mechanisms of reflectivity, emissivity, convection and conduction determine its temperature. The solar infrared region is different from the infrared energy given off by objects as heat. Beyond 2,500 nm there is little solar energy. As can be seen in Figure 1, the majority of the energy in the infrared range is found in the 700-1,200 nm range. Infrared (700-2,500 nm): Forty-five percent of the total solar energy is in the infrared region. Visible (400-700 nm): Roughly 50% of the sun's energy makes up the wavelengths that give us the perception of color. While UV only accounts for roughly 5% of the sun's energy that reaches the Earth's surface, it is a major contributor to the degradation of coatings. Ultraviolet (295-400 nm): The UV region starts at 295 nm where the atmospheric cut-off occurs. The sun's energy that reaches the Earth's surface is divided into three parts. Some variables and factors that can affect a coating's IR reflectivity are individual pigment selection, milling and dispersing, mixing IR-reflective pigments, opacity, and contamination.Īny discussion of IR coatings requires a short review of basic physics. ![]() This article is meant to inform chemists and formulators about some specific issues and phenomena pertinent to formulating and optimizing IR-reflective coatings. The Arctic line of pigments provides a palette of colors that allows the formulation of coatings and the design of materials to meet infrared reflectivity and long-term durability requirements, and provide deep and rich colors.Īrticles have been written about the pigments used to make infrared reflecting coatings. From these demands, Shepherd Color has developed a line of highly engineered products called Arctic® IR-reflective pigments. The key to fight this "White Blight" and produce innovative, colored IR-reflective coatings is to use pigments that absorb in the visible to produce color and reflect in the IR for coolness. TiO2 reflects in the visible and in the infrared. The easiest way to increase IR reflectivity is to use white pigments like titanium dioxide. ![]()
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