Dehumidification-adjustable cooling of radiant cooling terminals based on a flat heat pipe

Abstract

With increasing demand for building energy savings and comfort, radiant cooling systems have received increasing research attention, and novel radiant cooling terminals have been developed in recent years. However, poor surface temperature uniformity and the issue of coupled condensation prevention and cooling capacity remain the two major limitations of radiant cooling terminals. In this study, a novel radiant cooling terminal integrated with a heat exchanger and a flat heat pipe was developed. A novel cooling mode was proposed by using the flat heat pipe for sensible heat transfer only and the heat exchanger for both cooling and dehumidification. Furthermore, forced convection was added to the terminal to further optimize the cooling performance. Heat transfer analysis and thermal performance of the terminal were conducted. The novel terminal has advantages in thermal response speed (360–535 s) and surface temperature uniformity (±2 °C) due to phase change. The sensible and latent heat transfers were separated. The dehumidification-adjustable cooling method changed the cooling capacity of the terminal from 104.4 to 357.4 W, and the proportion of latent heat transfer varied between 12.1% and 26.4%, with preliminary results showing decoupled condensation prevention and cooling capacity improvement. Furthermore, adding forced convection increased this decoupling, and the surface temperature and cooling capacity simultaneously increased by 4°C-6°C and 75.7%, respectively. Cooling terminal performance improved owing to the dehumidification-adjustable cooling method, which had a referable application value.