Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

Abstract

a b s t r a c tDehumidification is responsible for a large part of the energy consumption in cooling systems in high humidity environments worldwide. Improving efficiency is therefore essential. Liquid desiccants offer a promising solution for dehumidification, as desired levels of humidity removal could be easily regulated. The use of membrane contactors in combination with liquid desiccant is attractive for dehumidification because they prevent direct contact between the humid air and the desiccant, removing both the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface can lower the expected desiccation rate per unit of desiccant surface area. In this context, hollow fiber membranes present an attractive option for membrane liquid desiccant contactors because of their high surface area per unit volume. We demonstrate in this work the performance of polyvinylidene fluoride (PVDF) based triple-bore hollow fiber membranes as liquid desiccant contactors, which are permeable to water vapor but impermeable to liquid water, for dehumidification of hot and humid air.

Vacuum membrane distillation of liquid desiccants utilizing hollow fiber membranes

“…However, the best candidates for fresh water recovery that have both energy efficiency and a compact design are processes typically used in seawater desalination, including electrodialysis [26][27][28], reverse osmosis [29], and membrane distillation [16][17][18][19][20][21][22]. The use of membrane contactors with inorganic salt solutions has been used for a number of processes, including but not limited to dehumidification, forward osmosis, and water treatment [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Membrane distillation (MD), e.g.…”

Hollow fibre membrane-based liquid desiccant humidity control for controlled environment agriculture

“…An array of hydrophobic PVDF hollow fibre membranes was positioned adjacent to the side of the hydroponics unit for dehumidification. The hollow fibres were manufactured in the lab using Hollow fibre membranes with liquid desiccant inside the techniques as described in Bettahalli et al, (2016). Scanning electron microscope (SEM) images of hollow fibres are shown in Figure 2.…”

Gas-Liquid Hollow Fiber Membrane Contactors for Different Applications

“…Liquid desiccants for air dehumidification can be divided into two broad ranges: (1) aqueous solution of salt desiccants-for example, lithium chloride (LiCl) [42,130,131] or calcium or magnesium chloride (CaCl 2 or MgCl 2 ) [132,133] that usually used for residential and commercial building applications, (2) glycols, like tri-ethylene glycol (TEG), which are frequently used for industrial applications [134]. The work [135] is worth of being noted individually; it employs chilled water as a desiccant for air control in spacecraft applications.…”

“…Some researchers propose to employ novel hollow fibers combined with conventional desiccants. Authors of the work [132] propose employing tri-bore hollow fibers from PVDF with CaCl 2 solution. In contrast, it is proposed to employ membrane contactors that are based on commercial fibers from Pebax ® 1074 and novel alkoxylated siloxane liquid desiccant (Dow CorningXX-8810) with a significantly reduced vapor pressure dependence on temperature [126].…”