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  3. 1 a surface is designed for use in space it...

Question: 1 a surface is designed for use in space it...

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1. A surface is designed for use in space. It has spectral hemispherical properties as show below A (um) 1.0-2.6 2.6-10.0 10.-100.0 αλ 0.65 0.80 0.25 0.10 0.35 0.20 0.75 0.90 With receiving the solar radiation (G, with the assumption of gray property), the surface which is installed on a spacecraft is maintained at 350K. (a) Calculate the total hemispherical emissivity (e) (b) calculate the total hemispherical absorptivity (a); and (c) determine the value of G (in kJ/m) Note: Table of blackbody radiation function is enclosed for your convenience (25%) 2. There are two primary types of solar thermal collectors. One is the flat-plate collector and the other is the evacuated-tube collector. It is generally agreed that the evacuated- tube collector is a better choice as being used in the high-latitude region than the flat-plate collector, why? (20%) Solar radiation on a horizontal surface integrated over the hour 11:00 to 12:00 on January 9 at Boulder, USA. (ф 40N) is 402 kl/m2. What is the sky clearness index kT for that hour? Estimate the fraction of the hours radiation that is diffuse by using the correlation model of Erbs, et al. as shown below. 3. for kT S 0.22 0.951 1-0.1604 kr + 4388k-16.638婷+ 12.336婷 for 0.22 < kt -= .0.8 for k >0.8 (25%) 4. On January 7 of 2019 in Tainan, Taiwan (121 E, 23 N), the total radiation (measured on horizontal plane, ID) for the hour 9 to 10 AM (the local solar time) is 1.10 MI/m2 Estimate the total radiation and its three components (i.e., beam, diffuse, and ground-reflected radiation) on a surface facing 25 eat of south with the tilt angle of 30 by using both the isotropic and anisotropic (Perez) models, respectively. The value for ground reflectance is set as 0.45. The d-kr correlation model is given by the following formulal: (30%) 0.9823 for 0 s kt S 0.2 d0.8066+1.9651k-6.5435k +3.8590 k? for 0.2ke s 0.75 0.2255 for kt >0.75
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