Numerical simulation on heating performances of a radiant-convective heating terminal

The hybrid radiant and convective heating system becomes more and more important in HVAC system due to its lower energy consumption and better thermal comfort. However, the existing radiant and convective heating system is complicated to provide a joint control. To solve this problem, a new kind of heating terminal of mixing radiation and convection was proposed, and its heating performances were numerically studied. Firstly, the numerical model was built, in which the air turbulent flow was calculated by the standard k-e model, while DO radiation model was employed to solve the radiant heat transfer. Secondly, the numerical model was validated by the experimental data. Lastly, influences of the important parameters including fin heights, fin pitches and refrigerant pipe spacing on heating performances were analyzed. The results showed that the increased fin height increased the total heating flux by 7.2-25.7% and metal weight by 1.4-5.7%. It was also concluded that with the increase of fin pitch and pipe spacing, the total heat flux decreased by 1.9-11.2% and 4.3-20.1% separately, and the metal weight decreased by 2.3-6.0% and 26.1-60.2%, respectively. This study provides support for the development of the hybrid radiant-convective heating system and energy saving of buildings.