Thermal transients in buildings: development and validation of a numerical model

The present paper describes the development of a simplified numerical model able to simulate thermal and hygrometrical transients in buildings and its validation by means of a climatic room. The numerical code is based on energy and mass balance equations and on the heat transfer equation for time-dependent conduction. The program calculates the indoor air temperature and the temperature of the inner surface of the walls according to the geometrical characteristics and thermophysical properties of the walls, the transients of outdoor temperature, the air renewals and the supplied heat flow. Validation of the code was carried out by means of a test room immersed in an artificial, controlled climate, to achieve definite and repeatable boundary conditions. Comparison between the experimental data and the numerical results for thermal unsteady state conditions shows a good agreement and bears witness to the reliability of the simulation program.