Developing a collaborative control strategy of a combined radiant floor cooling and ventilation system: A PMV-based model

The development of collaborative control strategies for radiant cooling and ventilation systems improves thermal comfort and energy efficiency. This study used the Transient System Simulation (TRNSYS) tool integrated with the parametric simulation manager jEPlus to determine the optimal starting and operation mode of a combined radiant floor cooling (RFC) and ventilation system. The results were validated by an experiment. The optimization process was constrained by the thermal comfort defined by the predicted mean vote (PMV) with the objective of minimizing energy consumption. The results showed that the ventilation system was started 1 h earlier than the RFC system at an initial indoor humidity of 85% to prevent condensation, whereas both systems were started at the same time at 75% in the starting stage. In the operation stage, the self regulation potential of the RFC system and the adjustment of the cooling capacity of the ventilation system were coordinated to counter dynamic internal heat gains. Moreover, the proportion of the total sensible heat removed by the RFC system to the total sensible heat removed by the ventilation system (S-v/S-R ) was positively correlated with the total energy consumption. The S-v/S-R must be sufficiently high to prevent a large PMV deviation from the comfort zone of-0.5 to 0.5. A collaborative control strategy using the PMV-based model was proposed to adjust the S-v/S-R according to the PMV range, resulting in a highly efficient operation and maximum energy savings of 26.2%.