| Research Highlights are brief summaries of recently completed studies. The research reports in their entirety are available through the
http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/96217.htm
Introduction
Moisture is the leading cause of damage in high-rise residential buildings. The use of advanced computer simulation techniques to examine the hygrothermal performance (combined heat, air and moisture transfer) in high-rise buildings has the potential to lead to improved building design. The main objective of this joint IRC-CMHC research project was to examine the use of modelling to predict the hygrothermal performance of a few selected high-rise wall and roof systems and to predict the long-term performance of various retrofit strategies from which these wall systems could benefit. The prediction of the long term hygrothermal performance of residential building components is important in assessing the durability, the energy efficiency and the effects of rehabilitation of high-rise structures.
Research Program
The heat, air and moisture transport in high-rise residential buildings is a complex hygrothermal process. Some of the transport mechanisms that must be considered in a computer simulation include: water vapour transport; liquid water transport; moisture capacity in the materials; condensation and evaporation processes; freezing and thawing processes; incident solar radiation and sky radiation; rain penetration; and air flow through and around the building envelope.
Much of this research project involved adapting a computer simulation model and determining the sensitivity of the simulation of hygrothermal processes in high-rise residential buildings to various factors, including the accuracy of material properties, the initial conditions and the boundary conditions. A number of existing simulation programs available world-wide were examined but no single model had all of the features needed to fully address the transport of moisture in high-rise residential buildings. The decision was made to further expand and improve a program previously developed by IRC called LATENITE, which incorporated all features needed other than that of air flow.
Once satisfied with the computer simulation program, 1-dimensional analyses were carried out. This was supplemented with more sophisticated 2-dimensional analyses on an additional, limited number of building assemblies. | 