A radiant floor cooling system (RFCS) is a high-comfort and low energy consumption system suitable for residential buildings. Radiant floor systems usually work with fresh air, and their operating performance is affected by climatic conditions. Indoor and outdoor environmental disturbances and the system’s control strategy affect the indoor thermal comfort and energy efficiency of the system. Firstly, a multi-story residential building model was established in this study. Transient system simulation program was used to study the operation dynamics of three control strategies of the RFCS based on the calibrated model. Then, the performance of the control strategies in five climate zones in China were compared using multi-criteria decision-making in combination. The results show that control strategy has a negligible effect on condensation risk, but the thermal comfort and economic performance differ for different control strategies. The adaptability of different control strategies varies in different climate zones based on the consideration of multiple factors. The performance of the direct-ground cooling source system is better in Hot summer and warm winter zone. The variable air volume control strategy scores higher in Serve cold and Temperate zones, and the hours exceeding thermal comfort account for less than 3% of the total simulation period. Therefore, it is suggested to choose the RFCS control strategy for residential buildings according to the climate zone characteristics, to increase the energy savings. Our results provide a reliable reference for implementing RFCSs in residential buildings.

This study conducted the numerical simulation to evaluate the performance of a ductless personalized ventilation (DPV) combined with radiant floor cooling system (RFCS) and displacement ventilation (DV) system. In the non-DPV cases, DV supplies air at temperature of 16 °C and 20 °C, respectively with a flow rate of 2.4 ACH. In the cases with DPV, DPV supplies personalized air, which is drawn at the height of 0.1 m or 0.2 m above the floor, to the face of a seated occupant at flow rates of 3 L/s, 5 L/s and 7 L/s, respectively. The horizontal distance of 0.3 m is designed between DPV air supply opening and occupant face at the height of 1.2m. For all the cases, the floor cooling temperature is set to 20 °C. The vertical air temperature difference at 1.1 m and 0.1 m (ΔT_1.1-0.1), the contaminant removal effectiveness (ε) and the draft rate at the occupant face (DR_face) are mainly used as evaluation indices to quantify the ventilation effectiveness and thermal comfort effect. According to the results, DPV remarkably decreases ΔT_1.1-0.1 with a maximum reduction of 1.79 °C compared to non-DPV case. DPV significantly influences the temperature adjacent to the face at the breathing zone, with a maximum reduction of 4.44 °C from non-DPV case to DPV case. DPV cases also effectively improve ε at breathing region compared to the non-DPV case. The DR_face ranges from 9.01% to 21.33% when different flow rates of DPV are used. In summary, the case using DPV flow rate of 5 L/s and at intake height of 0.1 m presented relatively better ventilation effectiveness and thermal comfort environment around the occupant.