Topic
Thermal radiation
About: Thermal radiation is a research topic. Over the lifetime, 12290 publications have been published within this topic receiving 197186 citations. The topic is also known as: heat radiation.
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TL;DR: The influence of thermal radiation and heat generation on an unsteady two-dimensional natural convection flow in an inclined enclosure heated from one side and cooled from the adjacent side under the influence of a magnetic field using staggered grid finite-difference technique has been studied in this paper.
58 citations
TL;DR: In this paper, a new optimization method was proposed to maximize the reflectivity of the near infrared (NIR) region to reduce thermal heating, while for aesthetic appeal they also minimize the visible (VIS) reflected energy received by human eyes, especially at wavelengths where eye sensitivity is high.
Abstract: Pigmented coatings with high reflectivity against solar irradiation can be used to control unwanted thermal heating that occurs as materials absorb sunlight such as heat in buildings that increases cooling loads. However, these surfaces produce glare that is unpleasant to the eye, and the coatings themselves can damage the appearance of the coated object. We introduce a new optimization method that embraces both thermal and aesthetic requirements. Our proposed coatings maximize the reflectivity of the near infrared (NIR) region to reduce thermal heating, while for aesthetic appeal they also minimize the visible (VIS) reflected energy received by human eyes, especially at wavelengths where eye sensitivity is high. The optimization parameter is defined as the ratio of the total reflected energy in the NIR region to that in the VIS region weighted by human eye sensitivity. Titanium dioxide is used as the pigment, and databases of its radiative properties are constructed using the Mie theory. To compute reflectivity, nongray radiative heat transfer in an anisotropic scattering monosized pigmented layer, with independent scattering, including direct and diffuse solar irradiations, is analyzed using radiation element method by ray emission model (REM2). Colors are calculated and optimization parameter is evaluated by using spectral reflectivity. Finally, the optimum values of particle size, volume fraction of pigment, and coating thickness are obtained.
58 citations
Patent•
11 Feb 1993
TL;DR: In this article, a hollow envelope reflecting incident radiation and thermal radiation from the semiconductor wafer surrounds and is spaced from the chamber and the bank of lamps, where a source of said incident radiation disposed adjacent a second opening produces radiation within said spectral band which enters said envelope and is reflected inside the envelope to illuminate a selected spot on the wafer hemispherically.
Abstract: Pyrometer apparatus measures the temperature of a semiconductor wafer which when heated by radiation from a bank of lamps emits thermal radiation which includes radiation contained in a selected spectral band. The apparatus includes a reaction chamber supporting the wafer and disposed above the bank of lamps. A hollow envelope reflecting incident radiation and thermal radiation from the wafer surrounds and is spaced from the chamber and the bank of lamps. A portion of the reflected radiation and the thermal radiation passes upwardly through a first opening. A source of said incident radiation disposed adjacent a second opening produces radiation within said spectral band which enters said envelope and is reflected inside the envelope to illuminate a selected spot on the wafer hemispherically. The spot reflects a portion of the incident radiation upwardly through the first opening. A device disposed outside of said envelope adjacent and above the first opening in the path of the reflected portion of incident radiation and said upward portion of wafer thermal radiation and responds within said spectral band to both of said portions to produce a first electrical signal proportional to the said reflected portion of incident radiation and a second electrical signal proportional to said upward portion of wafer thermal radiation. Another device responds to the first and second electrical signals to calculate the temperature of the wafer.
58 citations
TL;DR: In this paper, a Plano-convexquartz window was introduced with the aim to minimize heat flux gradient of the porous medium receiver, and the thermal performance of the receiver was numerically studied while the fluid inlet is located at the side wall.
58 citations