Performance analysis of a hybrid non-centralized radiant floor cooling system in hot and humid regions

Radiant floor cooling (RFC) systems are known for their energy efficiency and comfort. However, when a conventional intermittently operating RFC system is subjected to sudden increases in heat and moisture loads, condensation, difficulties with multi-zone temperature control, inadequate cooling capacity, thermal comfort degradation, and slow thermal response may occur. A non-centralized hybrid RFC system was established with an air source heat pump, floor coils of high thermal mass, fan coils, and an outdoor air dehumidifier. The thermal comfort and cooling capacity of a given thermal zone under four modes were tested and analyzed. The results showed that the system created a satisfactory indoor environment with multi-zone control. The precooling direct-expansion (DX) outdoor air dehumidifier combined with the fan coils served the role of a conventional dispersed DOAS (dedicated outdoor air system), improved the response of the radiant system, and assisted in dehumidification. A PID-based mixing valve allows the floor surface temperature to track the dew point temperature of the zone air to improve floor cooling capacity. This hybrid system is suitable for residential homes or offices with non-centralized air conditioning systems to handle transient heat and moisture load variations.