Multi-objective optimization of radiant floor cooling with dedicated outdoor air systems: Integrating sensitivity analysis and decision-making.

Radiant floor cooling systems (RFCS) and dedicated outdoor air systems (DOAS) deliver significant energy efficiency and thermal comfort benefits in residential applications. Nevertheless, determining optimal operational parameters presents challenges, particularly under variable occupancy levels. This study establishes an optimization framework combining sensitivity analysis (SA), multi-objective optimization (MOO), and decision-making methodologies to minimize energy consumption while maximizing thermal comfort simultaneously, quantified through predicted percentage dissatisfied (PPD) metrics, subject to condensation prevention constraints. Employing the Morris and the Sobol method identified critical parameters: outdoor supply air volume demonstrated the most decisive influence on energy consumption, with a total order index of 0.67. Clothing insulation exhibited a paramount impact on thermal comfort, registering a first order and total order index of 0.24 and 0.65, respectively. The non-dominated sorting genetic algorithm II (NSGA-II) generated Pareto-optimal solutions across occupancy scenarios of three to seven occupants, from which the entropy weight-technique for preference by similarity to ideal solution (EW-TOPSIS) selected compromise solutions with dynamically adjusted objective weights. Results maintained thermal comfort within the ASHRAE Standard 55 prescribed range, achieving PPD values between 5 % and 10 %, indoor temperatures of 25.5 ◦C–27 ◦C, and relative humidity levels of 64 %–76 %. Objective weighting shifted substantially with occupancy: energy consumption priority decreased from a weight of 0.90 for three occupants to 0.67 for seven occupants, while thermal comfort emphasis increased correspondingly from 0.10 to 0.33. The integrated methodology provides a robust approach for intelligent design and operation of combined RFCS and DOAS, recommending its adoption to balance energy conservation with occupant comfort requirements effectively.