Experimental investigation on condensation characteristics of a novel radiant terminal based on sepiolite composite humidity-conditioning coating

Abstract

The problem of condensation hinders the application and popularization of the radiant cooling system. According to the characteristics of temperature and humidity independent control of the radiant cooling system, a novel humidity-conditioning radiant terminal combined with solid humidity-conditioning material is proposed which can control temperature and humidity simultaneously, and a sepiolite composite humidity-conditioning coating (SCHCC) suitable for the radiant terminal with good humidity control ability in high relative humidity environment is prepared. The humidity-conditioning coating can adsorb water vapor in the air to reduce the risk of condensation that is different from the surface condensation of traditional radiant terminals. Then, the condensation and desorption characteristics of three humidity-conditioning boards are tested which is considered scaled-down humidity-conditioning radiant terminal. The results show that SCHCC has good humidity control ability in a high relative humidity environment, the moisture adsorption capacity of SCHCC between 85% RH and 95% RH is 0.208 g/g, which is 11.43 and 22.47 times that of gypsum and diatomite. The sepiolite based humidity-conditioning board (SHCB) with the best moisture adsorption characteristics has the longest condensation time, and the condensation time increases with the decrease of undercooling. SHCB also shows better humidity control ability even for the experimental condition without condensation within 300 min. In summary, SHCB can reduce the moisture content of indoor air through its excellent hygroscopic properties, and reduce the risk of condensation at the radiant terminal. • A novel humidity-conditioning radiant terminal is proposed. • The material has good humidity control ability under high relative humidity. • The condensation and desorption behavior of the novel radiant terminal is tested. • The novel radiant terminal can effectively prolong the surface condensation time.