A non-intrusive experimental study on the thermal characteristics and grey-box modeling of underfloor heating in residential buildings

초록

This study presents a non-intrusive experimental approach combined with a grey-box modeling framework to analyze the thermal behavior of residential buildings equipped with underfloor radiant heating systems. Infrared thermography was employed to capture the spatial non-uniformity of floor surface temperatures, while indoor air temperature and heating energy consumption were measured over a 22-day winter period. To evaluate the impact of occupant behavior, scenario-based modeling was conducted for both door-open and door-closed conditions. The results demonstrated that door status significantly affects inter-room heat. Remarkably, the thermal behavior under these scenarios could be accurately captured by modifying only the thermal resistance between the living room and adjacent rooms, reducing it to just 2.5-5% of its original value in the door-open case. A detailed 24-resistor, 17-capacitor (24R-17C) model comprising 50 parameters was initially developed. This model was subsequently simplified to a 24R-8C version with 41 parameters by applying a floor-area-based scaling approach to floor thermal capacities based on previous study. The simplification retained physical consistency and interpretability while enhancing computational efficiency. Model estimation results showed strong predictive accuracy, with RMSE values ranging from approximately 0.45 degrees C to 1.15 degrees C for both indoor air and floor surface temperatures. The proposed modeling approach offers a practical and accurate representation of thermal dynamics in multi-zone residential buildings and shows strong potential for applications in modelbased predictive control and energy optimization.

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