摘要

Radiant system is claimed as a promising technique for temperature and humidity independent control with great potential in improving indoor thermal comfort. The main challenge is the condensation risk. To guarantee total heat flux density while simultaneously avoid condensation requires good control strategies. This paper reports a study on the so-called safety operation zone concept based on the inherent correlation between the total heat flux density and panel surface temperature of the radiant system revealed from the experimental results. Experiments were carried out in a climate chamber under different combinations of supply water temperature and operative temperature. Results showed that the total heat flux density and the panel surface temperature were mutually constrained within a rhombus. However, not all the conditions represented by the rhombus are allowable when considering water condensation risks in cooling conditions, thus a so-called safety operation zone concept is proposed. Principle of the safety operation zone and the possible applications are illustrated. Furthermore, a simplified panel surface temperature model was developed and based on which the condensation free control logic was proposed. The results reported in this paper would assist engineers to better design, operate and control radiant systems for improved indoor thermal control performance.