Comfort and energy consumption of hydronic heating radiant ceilings and walls based on CFD analysis

This article presents the methodology and results of a hybrid numerical optimization study of a heating ceiling and wall hydronic radiant panel system in a typical residential building located in Quebec City, Canada. The comfort and energy consumption of the system are the two figures of merit that are considered in the multiobjective optimization analysis. The main design variables are the position and dimension of the panels, and the fluid inlet temperature. The hybrid numerical method features a 2D CFD model of a typical empty room, coupled with a semi-analytic radiant panel model specially developed for coupling with CFD. This strategy allows considering the real room geometry, while providing at the same time accurate temperature profiles of the radiant panels and detailed temperature and comfort data field in the room. The results show that there is no unique optimal solution but rather a family of optimal designs (Pareto fronts) for which the solutions are trade-offs between the two objectives. When adjusting correctly the fluid inlet temperature, it is also possible to achieve nearly Pareto optimal solutions, even when reducing the total panel surface by 66%. This means that the temperature control of the fluid is the most important parameter for maximizing comfort and minimizing energy consumption of hydronic heating radiant panels.

► A CFD model of a room coupled with a semi-analytical radiant panel model are used.
► Fluid inlet temperature as well as position and dimensions of panels are optimized.
► Multiobjective optimization is considered for energy consumption and comfort.
► The fluid inlet temperature is the most important optimization parameter.
► It is possible to reduce total surface of panels while keeping good performances.