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Temperature and Vapor Pressure Gradients Across Wall Assemblies Using Microcomputer Graphics
Author(s) -
FAZIO P.,
GoWRI K.
Publication year - 1988
Publication title -
computer‐aided civil and infrastructure engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.773
H-Index - 82
eISSN - 1467-8667
pISSN - 1093-9687
DOI - 10.1111/j.1467-8667.1988.tb00166.x
Subject(s) - autolisp , microcomputer , base (topology) , computer science , fortran , graphics , thermal insulation , glazing , mechanical engineering , materials science , engineering drawing , engineering , composite material , computer graphics (images) , layer (electronics) , telecommunications , mathematical analysis , chip , mathematics , operating system
An educational microcomputer graphics program for predicting the temperature and vapor pressure gradients across external wall assemblies is developed to assist designers in evaluating the performance and selection of materials. A large number of constructional types and combinations of materials are available to satisfy the various functional requirements such as structural, thermal, acoustic, etc., of an external wall. This paper presents the methodology used in organizing the material properties information in a data base within a general purpose drafting program for diagnosing the problem of condensation within the wall assembly. Specifying the thickness and the material properties used for structure, insulation, cladding, etc., one can obtain the variation in temperature across the different layers of the wall for a set of given indoor and outdoor design temperatures. The condensation problem in the wall assembly can be investigated by knowing the relative humidity of the indoor and outdoor environment. Many different wall types such as cavity walls, walls with interior and exterior insulation, metal and timber clad walls can be analyzed for a number of different combinations of materials and various thicknesses. AutoLISP in the AutoCAD environment is used for the material properties data base, calculations, and drafting. A program of this kind is an effective tool for the students of building science in the analysis of external walls for design and retrofitting, and understanding the principles involved.