This digital document is an article from ASHRAE Transactions, published by American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. on January 1, 2010. The length of the article is 8542 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available immediately after purchase. You can view it with any web browser.

From the author: Heat flow through the test frame was measured in a hot-box set-up with the insulation side of the test frame facing air kept at an average temperature of 311.2 K (100.5[degrees]F) and the roof side facing air maintained at an average temperature of 283.4 K (50.4[degrees]F). Mathematical modeling involved the formulation of the steady-state, three-dimensional natural convection and heat transfer problem in the SSR assembly. The model accounted for the relevant geometrical complexities and allowed for variations in fiberglass insulation thermal conductivity with density (i.e., compressed thickness). The governing transport equations and the boundary conditions were solved numerically using CFD software Fluent. Excellent agreement was observed between model predictions of the overall heat transfer coefficient (U-factor) and calculations based on experimentally measured values. The model predicted U-factor was 0.369 W/[m.sup.2] K (0.065 Btu/[ft.sup.2] * h * [degrees]F) when natural convection in various air gaps was accounted for and 0.358 W/[m.sup.2] K (0.063 Btu/[ft.sup.2] * h * [degrees]F) when the air was assumed to be stagnant. The measured value was 0.349 W/[m.sup.2] * K (0.061 Btu/[ft.sup.2] * h * [degrees]F).

Citation Details
Title: ASHRAE Standard 90.1 metal building U-factors–Part 1: mathematical modeling and validation by calibrated hot box measurements.(Report)
Author: M.K. Choudhary
Publication: ASHRAE Transactions (Magazine/Journal)
Date: January 1, 2010
Publisher: American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc.
Volume: 116 Issue: 1 Page: 157(12)

Article Type: Report

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