Performance characteristics assessment of hollow fiber membrane-based liquid desiccant dehumidifier for drying application

Abstract

• Proposed novel integral technique based analytical model to assess HFLDD performance. • Analyzed the influence of inlet and design parameters on HFLDD performance. • Effect of Le and St numbers across and along the HFLDD is evaluated. • Case study on conventional/desiccant dryer performance is analyzed in humid climate. • Desiccant dryer found to be best alternative for humid climatic conditions. In the present study, a novel integral technique based two-point boundary value problem is developed using the simplified polynomial equations to assess the hollow fiber membrane-based liquid desiccant dehumidifier performance for drying application. The developed numerical technique is validated with the experimental data available in the literature and observed a maximum deviation of ± 9.7%. The liquid desiccant chosen is lithium chloride. By considering thermal and moisture effectiveness as performance parameters and choosing the air inlet temperature, air specific humidity, desiccant temperature, and liquid to gas ratio as input parameters, the influence of Lewis number and Stanton number on dehumidifier performance is analyzed. The performance analysis concluded that a high liquid to gas ratio, desiccant temperature, and specific humidity enhance the dehumidifier performance. Further, the variation of performance parameters along the length and thermal mass of the membrane column is also assessed. Moreover, a case study on conventional and desiccant dryers performance in humid climates is assessed and observed that the desiccant dryer is the best alternative compared to the conventional dryer. In addition, for the given operating range and inlet condition, the maximum possible vapour absorption rate (δ VAR ) and energy exchange for the conventional dryer is found to be 93 g/hr and 0.8 kW, whereas, for the desiccant dryer, it is 164 g/hr, and 1.4kW respectively.