Numerical and experimental study on the characteristics of radiant ceiling systems

Insufficient knowledge about characteristics of radiant systems has caused problems in the wider application of the radiant system, such as water condensation, bad thermal comfort, etc. In this study, key characteristics of a radiant system in terms of an inherent relationship between total heat flux and surface temperature were analysed. General models for describing such the relationship were developed and validated by elaborate experimental data. Operation limit region of the radiant system was identified and proposed by plotting key parameters in one surface, including supply water temperature, operative temperature panel surface temperature as well as total heat flux density. It was found that not all of the points within the operation limit region were suitable for practical application in order to avoid water condensation risk in cooling mode and large temperature differences in a vertical direction in heating mode. Evolved forms of operation limit regions for cooling and heating applications were put forward and their characteristics were addressed. The results reported in this paper could help manufacturers as well as engineers to better design, configure and regulate radiant systems for better product development and improved indoor thermal comfort.