Evaluation of membrane-based air pre-dehumidification for a capillary radiant air conditioning system

Abstract

The polyvinylidene fluoride hollow fibre membrane air dehumidification tests were carried out between the liquid desiccant solutions and the wet air. Three liquid desiccant solutions of LiBr solution (50%), LiCl solution (35%) and CaCl₂ solution (40%) were tested under different wet air conditions. The results showed that all the membrane dehumidification processes were stable. The air moisture content in the outlet of the membrane was maintained as 6.5 g/kg (da)–8.2 g/kg (da) when the air moisture content in the inlet of the membrane was operated from 17.1 g/kg (da) to 32.4 g/kg (da). The dehumidification amount of LiBr solution (50%) and LiCl solution (35%) was more productive. On this basis, a membrane-based air pre-dehumidification process for the capillary radiant air conditioning system was built. Since the ideal dew point temperature range of the indoor air is below 14–17°C according to the cold supply water, all the air moisture content at the membrane outlet is much lower than that of the ideal dew point temperature range, which means non-condensing occurs in the capillary tube surface. The membrane-based air pre-dehumidification process can easily form an adaptive regulation process of humidity with the capillary radiant air conditioning system under different environmental parameters.