condensation

In tropical humid climates, moisture and condensation on walls lead to significant damage of buildings. The purpose of this article is to present a numerical model to improve the prediction of internal humidity in buildings. Thermal simulation codes usually evaluate moisture due only to airflow transfers. The model presented takes into account the moisture transfers between walls and air inside a zone. It allows a forecast of the quantities of liquid condensed on a surface. An experimental comparison is presented to appreciate the improvement of the model.

Measurement were operated in Ottawa’s Laurier House (an historical house built in 1878 now being a museum) to determine the temperature and humidity conditions under which condensation occurs on ‘historic’ windows. Results lead to recommendations for oper

A condensing device allows to avoid condensation on cooling ceilings in rooms with humid air. It uses thermoelectric modules in contact with the cooling panels. The pumped heat is transferred into the cooling ceiling to keep its temperature above the dew point. Tests have been performed in a full-scale chamber. A set of condensing units was mounted on a standard hydraulic cooling ceiling. The control of temperature is achieved by regulating the mass flow of the water. By this method the loss of efficiency of the cooling panels is fully compensated.

This paper presents an approach to evaluate the sensitivity of a roof design to condensation problems, given the uncertainty to achieve continuity of airtightness in practice. The approach consists of a repeated number of simulations with a 2D heat, air and vapour transfer model to predict the variation in roof moisture performance due to various discontinuities in roof geometry. The set of discontinuities is calibrated by comparing measuring data of roof airtightness to simulation results.

States that condensation on windows is a major issue for building owners and managers. Tests were devised to counter the problems of sealing windows, test temperatures and cost and simulation testing for conventional testing procedures, and a database of windows that have undergone both tests and simulations for resistance to condensation was compiled. Three double hung windows of varying materials were tested as well as designs for air infiltration at several levels of airtightness.

Natural ventilation systems for industrial buildings have traditionally been designed using empirical engineering models, which often require the designer to 'over-engineer' the design to achieve a 'guaranteed' level of ventilation performance. This paper describes an application of computational fluid dynamics (CFD) and multi-zone thermal and airflow modelling to analyse the effectiveness of natural ventilation in removing moisture from a red mud filtration building used in the alumina industry in Australia.

Condensation on windows creates obscured view, can cause building damage, and may lead to mold growth and poor indoor air quality. The Canadian Standards Association (CSA) has developed new procedures to evaluate window condensation potential, using a combination of computer simulation and testing. This paper summarizes results of a study into various aspects of computer simulation related to the evaluation of condensation potential. These findings were used to assist in the development of the CSA procedures.

The methodology of risk analysis and assessment is reviewed and applied to study the reliability of condensation control measures in lightweight building envelopes. It is generally recognized that airtight construction is an essential part of condensation control. Nowadays, different air barrier systems are developed and documented to prevent air leakage and moisture accumulation in the envelope. But does this mean that the condensation risk is sufficiently minimized and that the protective system is reliable?