Feasibility study of simplified pipe modeling for analyzing thermal performances of radiant heating and cooling systems

Energy-efficient radiant heating and cooling require surface temperature and thermal capacity analysis. Simplified pipe modeling is applied to save time and resources for numerical analysis when evaluating the radiant system. Therefore, this study investigated the surface temperature distribution and thermal capacity of a radiant system using simplified pipe modeling. To do this, a steady-state heat transfer simulation was performed using Physibel BISCO. The difference between detailed (circular) and simple (rectangular) pipe models and the effect of material thermal conductivity of various layers were analyzed in three types of radiant heating and cooling systems: Embedded Surface System (ESS), Thermally Activated Building System (TABS), and Cooling Radiant Ceiling Panels (CRCP). The simple and detailed ESS and TABS simulation results showed similar surface temperature and heat capacity in various materials. Also, the CRCP simple and detailed models for materials differed in surface temperature and heat capacity, especially when the pipe thermal conductivity was high. The CRCP simple model overstated surface temperature and thermal capacity, which needs heat resistance to solve this overestimation. Further studies are necessary to investigate the discrepancy with different dimensioning and operation conditions, such as water temperature and flow rate.