A zero‐dimensional model for the analysis of radiant hydronic panels with solid layer

Radiant hydronic panels are heat exchangers particularly suitable for residential heating because of the higher energy saving and thermal comfort compared to traditional heating systems. As a consequence of these attractive features, interest in developing more efficient and less costly designs has strongly increased in the last few years, as demonstrated by the various approaches to predict design and off-design performance that have appeared in the literature. In this paper, a zero-dimensional model taken from the literature is improved to study the performance of a commercial radiant heating panel in which the water tube is embedded in a solid conductive layer. The solid layer is included in the panel casing to improve heat transfer and smooth the surface temperature gradient. Heat transfer through the panel and along the radiant surfaces is modelled by a network of thermal resistances. The model allows the heat transfer in off-design steady-state conditions to be calculated for given values of all the network resistances. The off-design numerical results are in good agreement with the experimental data provided by the panel manufacturer. Panel heat output is also calculated for several tube materials to show the capability of the model to evaluate the impact of the main design parameters on the panel performance.