3D numerical model for transient simulations of floor cooling capacity and thermal comfort in a thermally heterogeneous room

Abstract

This study presents the development of a computational model for an analysis of the dynamic heat transfer in a room equipped with the radiant cooling floor as a full, three-dimensional, thermally heterogeneous environment. The model is validated by comparison with the results of reference models and by the full-scale experimental measurements, which prove the good accuracy of the developed model for the simulation of heat gains in a thermally heterogeneous room (mean error 0.23 °C for the air temperature), as well as for the simulation of radiant floor cooling (mean error 0.16 °C for the temperature of floor area). A set of simulations is performed for an exemplary room with solar, long-wave, and convective heat gains to investigate the effects of type and time-variability on the heat gains for the operational characteristics of the cooling floor. Different types of temperature sensors (operative and air) used in the control system with different set-points are examined. Thermal heterogeneity of the room is included in the thermal comfort analysis performed using PMV, PPD, and PD-cold floor comfort indicators. It is found that the operational characteristics of the radiant floor strongly depend on the effects of dynamic heat flow, so it should be considered on the full spatial scale and the control strategy should not be neglected. It is desirable to develop design methods and tools for cooling floors that allow precise prediction of their operational characteristics but are not too computationally complex, which is satisfied by the proposed model.