DIGITHON: A numerical model for the thermal balance of rooms equipped with radiant systems

Water based surface embedded heating and cooling systems have gained appreciable interest and success for a variety of applications in new buildings and renovations. Some problems related to the correct design of these systems were solved a long time ago, but some uncertainties still remain, especially as regards the thermal behaviour under transient conditions. In this context a numerical model able to perform the detailed simulation of the dynamic behaviour of water based surface embedded heating and cooling systems developed by authors is presented in this paper. It is validated versus test room measurements. In order to perform the validation under real use boundary conditions, the test room was subjected to heating/cooling load profiles aimed to simulate different climatic conditions which have to be faced by ceiling radiant panels. The results achieved show that the presented model can predict the real room conditions and that results are not affected by the use of variable or fixed convective heat transfer coefficients.

► A model for simulating rooms with radiant systems has been developed.
► A room with high accuracy for testing radiant systems has been built up.
► A suitable procedure for imposing heating/cooling loads has been developed.
► The mathematical model has been tuned on experimental data.
► Fixed convective heat exchange coefficients could be used for simulations.