Dynamic Modeling and Experimental Validation of Floor Cooling Systems for Overheating Assessment and Condensation Risk Considerations in Residential Buildings

This study presents the development and experimental validation of a dynamic underfloor cooling system model aimed at improving the understanding of system-level thermal behavior in residential buildings. In the context of increasing summer heatwaves and overheating problems, a robust cooling solution is needed, particularly for dwellings with large glazed areas. In many regions, residential buildings are already equipped with hydronic underfloor heating systems, making them potentially suitable for adaptation to cooling without major modifications. Unlike conventional supply temperature control, the proposed modeling approach considers cooling output in relation to floor surface temperature and indoor air conditions, providing a physically consistent basis for assessing condensation-related constraints. Experimental data were collected from a full-scale nearly zero-energy (nZEB) residential building equipped with a hydronic underfloor cooling system. Measurements included return water temperature, cooling power, and floor surface temperature under varying operating conditions and supply temperature levels. The measured data were used to calibrate and validate the dynamic simulation model. Primary emphasis was placed on return water temperature and cooling power as robust system-level indicators, while floor surface temperature was used as a secondary reference for qualitative comparison. Performance was evaluated across different floor surface configurations and operating points. The results demonstrate that the calibrated model is able to reproduce the key thermal responses of the underfloor cooling system at the system level. This work provides experimental support for the use of dynamic simulation models in the analysis of residential underfloor cooling performance and forms a basis for future studies addressing advanced control concepts and condensation-safe operation.