U.S.S.R. experience in thermal design of building envelopes with improved thermal properties

Abstract

This paper deals with the U.S.S.R. experience on improving thermal design of enveloping structures of precast buildings of mass-scale construction. In such buildings, multi-layer enveloping structures with improved thermal properties are becoming increasingly used. They are characterized by non-homogeneity of materials in cross-section and complex butt joints for which methods of computer estimation of temperature fields had been developed. The paper sets forth methods for estimating two- and three-dimensional tasks of heat conduction making it possible to obtain temperature fields of surfaces of envelopes, the distribution of thermal flows, and on that basis to calculate the reduced total thermal resistance of the envelope. For the purpose of codification, based on numerous estimations of temperature fields, simplified design methods of estimation of such structures have been developed. Analytical expressions of thermal characteristics of enveloping structures with the most widely used thermal bridges are given. For design purposes, a data bank has been compiled on typical thermal bridges of enveloping structures in the U.S.S.R.