Parametric analysis of a cross-flow membrane-based parallel-plate liquid desiccant dehumidification system: Numerical and experimental data

Abstract

Operating parameters of a membrane-based parallel-plate liquid desiccant dehumidification system are investigated in this paper. The liquid desiccant and air are in a cross-flow arrangement, and separated by semi-permeable membranes to avoid carry-over problem. A numerical model is developed to simulate the system performance, and validated by experimental and analytical results. Impacts of main operating parameters on the system performance (i.e. sensible, latent and total effectiveness) are evaluated, which include dimensionless parameters (i.e. solution to air mass flow rate ratio * and number of heat transfer units ), solution properties (i.e. concentration and temperature ) and inlet air conditions (i.e. temperature , and relative humidity , ). It is found that * and are two of the most important parameters influencing the system effectiveness. Even though the system performance can be improved by * and , its increasing gradient is limited when * and exceed 1 and 4 respectively. Decreasing solution temperature does not make a great improvement to the system performance, however, increasing solution concentration is a good approach to enhance the latent effectiveness without influencing the sensible effectiveness. The system shows the broad adaptability in various weather conditions, and has the ability to provide relative stable state supply air.

Steady-state performance evaluation and energy assessment of a complete membrane-based liquid desiccant dehumidification system

“…Bai et al [14,15] experimentally and numerically studied the coupled heat and mass transfer of a full-scale flat-plate membrane-based dehumidifier, and found that and mass flow rate ratio ( * ) are the key parameters influencing the dehumidifier performance, and their effects are interacted with each other. Su et al [16] proposed a solarpowered absorption chiller combined with a liquid desiccant dehumidifier for space cooling and fresh water production, and their results reveals that the exergy efficiency for the proposed system is 2.97% higher than the reference system. Huang et al [17,18] studied the conjugate heat and mass transfer in a membrane parallel-plate contractor, and analysed the effects of local and mean friction factors, Nusselt number and Sherwood number.…”

The potential role of trans-critical CO2 heat pumps within a solar cooling system for building services: The hybridised system energy analysis by a dynamic simulation model

“…In the last years, new perspectives in the desiccant cooling system (DCS) have been derived, which are helpful to achieve an energy-efficient design by the heat-driven cooling equipment [ 11 ]. Thus, several studies analysed the impacts of the main operating parameters on systems performance [ 12 ], including dimensionless indicators, chemical solution properties and inlet air conditions, so as to improve the technologies deployment and their readiness [ 13 , 14 ]. Recently, Alahmer and Ajib reported in their impressive literature review which are the main barriers, challenges, and perspectives of solar cooling technologies wide deployment [ 15 ].…”

Influences of the mixed LiCl-CaCl2 liquid desiccant solution on a membrane-based dehumidification system: Parametric analysis and mixing ratio selection

“…Moghaddam et al [23] introduced a solution-side effectiveness to evaluate the impact of * on dehumidification and regeneration processes, and pointed out that the latent effectiveness difference between the air-side and the solution-side is can be neglected. Bai et al [24,25] experimentally and theoretically studied the operating characters of a parallel-plate membrane-based dehumidification system by focusing on various parameters, and identified the effects of and mass flow rate ratio ( * ) are interacted with each other. Some researchers developed different types of the membrane-based contractor.…”