Experimental study of the surface vapor pressure of a microencapsulated phase change material slurry liquid desiccant within the entire temperature range of a dehumidification system

Abstract

The surface vapor pressure is a critical physical property of a liquid desiccant, which has a direct influence on the mass transfer driving force in the dehumidification and regeneration process. In this study, a measurement system for the surface vapor pressure of the microencapsulated phase change materials slurry (MPCMS) was built using a static method. The surface vapor pressure of the MPCMS at 293.2 K–353.2 K was measured, which covered the entire range of dehumidification and regeneration. Experimental results showed that the surface vapor pressure of the MPCMS decreased compared with that of the pure LiCl solution. The surface vapor pressure drop ratio of the MPCMS increased with increasing MicroPCM and LiCl mass concentrations. The phase transition of the MicroPCMs intensified the drop in the MPCMS surface vapor pressure. When the MicroPCM and LiCl mass concentrations were 2 % and 40 %, respectively, and at the phase transition temperature of 303.2 K, the vapor pressure drop ratio reached a maximum of 17 %. A correlation for the MPCMS surface vapor pressure calculation was proposed, and the deviation between the calculated and measured values was less than 10 %. The results of this study provide basic data for the future development of the MPCMS liquid desiccant system.