Influence of air layer on temperature and humidity characteristics of outer envelope structure with internal heat insulation

Abstract

Objective. The article addresses the process of heat and mass transfer in outer envelope structure with internal heat insulation. To prevent condensate formation, it is proposed to use a ventilated air duct inside the wall structure. Methods. The study was carried out using numerical simulation methods. Air movement in the duct was described by solving the Navier-Stokes equation in k-ε approximation. Condensate formation was analysed via joint resolution of heat conduction and diffusion equations. The problem of heat and mass transfer was addressed for a structure with internal heat insulation, behind the layer of which an air duct was located with air movement occurring due to natural or forced convection. Results. As part of the work, it was shown that the use of an air duct significantly reduces the thermal resistance of the structure, and an increase in the airflow rate leads to a decrease in thermal resistance and the likelihood of condensate formation. A decrease in thermal resistance with an increase in air flow rate into interlayers occurs faster than an increase in the amount of air-entrained moisture. Conclusion. Results of the work have shown that the use of an air duct throughout the entire period of operation of a building is not effective, but it is proposed to use this duct periodically in winter to dry the condensate.