The REM 2 is a generalized method for calculating radiation heat transfer between absorbing, emitting and scattering media. A more refined and rigorous approach is applied using the Radiation Element Method by Ray Emission Model (REM 2). In the present work, the glass window is considered to be a participating non-gray media subjected to solar irradiation (specified by the spectral solar model proposed by Bird and Riordan, ) and thermal radiation (specified by blackbody emission of the outside and inside environment).
Moreover, the real and imaginary parts of the complex refractive index of glass are spectrally dependent. In reality, the transmittance, like reflectance and absorbance, is a function of wavelength, angle of incidence of the incoming radiation, the real part n and the imaginary part k of the complex refractive index of the glasscover. These assumptions may lead to considerable error in evaluating the thermal properties, heat flux and temperature distribution within the glass material subjected to irradiation. Therefore, the gray approach is often assumed for such calculation. In general the glass material is assumed to be transparent for the solar spectrum and opaque to radiation at infrared wavelengths. The accurate prediction of the temperature distribution through a glazing system depends strongly on how the glass material is analyzed. The result shows that increasing the air layer, the steady heat flux decreases and the temperature distribution within the glass changes. The calculation has been performed during winter period and the effect of the thickness of the glass for a single glazing and of the air layer between the two panels for double glazing has been studied. The optical constant of a commercial clear glass material have been used. Both solar and thermal incident irradiations are applied at the boundary surfaces using the spectral solar model proposed by Bird and Riordan. specular reflectivity, refraction angle and absorption coefficient) is taken into account. The spectral dependence of the relevant radiation properties of glass (i.e. The model allows the calculation of the steady-state heat flux and the temperature distribution within the glass cover. The glass window is analysed as a non-gray plane-parallel medium disctritized to thin layer assuming the glass material as participating media in one-dimensional case, using the Radiation Element Method by Ray Emission Model (REM 2). Keywords: Glass Window, Nongray Calculation, Radiative Heat Transfer, Temperature Distribution, Heat Flux, Heat GenerationĪccurate prediction of thermal radiation by applying rigorous model for the radiative heat transfer combined with the conduction and the convection has been performed for a single and double window glazing subjected to solar and thermal irradiation. Miller, Computational Methods of Neutron Transport, American Nuclear Society, 1993, ISBN: 2-4.1Civil and Architectural Engineering Department, College of Engineering, Sultan Qaboos University, Al-Khoud, Sultanate of Oman 2Institute of Fluid Science, Tohoku University, Katahira, Japan.Įmail: December 19 th, 2010 revised December 29 th, 2010 accepted January 5 th, 2011.
Hetrick, Dynamics of Nuclear Reactors, American Nuclear Society, 1993, ISBN: 3-2. Neuhold, Introductory Nuclear Reactor Dynamics, American Nuclear Society, 1985, ISBN: 9-4. Bezella, Introductory Nuclear Reactor Statics, American Nuclear Society, Revised edition (1989), 1989, ISBN: 3-2. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.
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