Indoor Humidity Analysis of an Integrated Radiant Cooling and Desiccant Ventilation System

Abstract

Radiant cooling is credited with improving energy efficiency and enhancing the comfort level as an alternative method of space cooling in mild and dry climates, according to recent research. Since radiant cooling panels lack the capability to remove latent heat, they normally are used in conjunction with an independent ventilation system, which is capable of decoupling the space sensible and latent loads. Condensation concerns limit the application of radiant cooling. This paper studies the dehumidification processes of solid desiccant systems and investigates the factors that affect the humidity levels of a radiantly cooled space. Hourly indoor humidity is simulated at eight different operating conditions in a radiantly cooled test-bed office. The simulation results show that infiltration and ventilation flow rates are the main factors affecting indoor humidity level and energy consumption in a radiantly cooled space with relatively constant occupancy. It is found that condensation is hard to control in a leaky office operated with the required ventilation rate. Slightly pressurizing the space is recommended for radiant cooling. The energy consumption simulation shows that a passive desiccant wheel can recover about 50% of the ventilation load.