Quick performance prediction for internally cooled/heated liquid desiccant dehumidification system

Abstract

Predicting the performance of internally cooled/heated liquid desiccant dehumidification system is complicated, which requires a large number of iterative calculations. This article numerically developed a quick prediction method for falling film dehumidifiers and regenerators in internally cooled/heated liquid desiccant dehumidification system by non-linear regressions, to predict the mass transfer performance directly with design variables, including inlet parameters of fluids (air, desiccant, and heating/cooling fluid) and system configuration (size, air channel thickness wetting factor, and flow pattern). The LiCl and water were chosen as the solution and cooling/heating fluid. Comparison shows that differences between our results and those by existing mathematical models are acceptable, with an average absolute error of 8.0% for dehumidifiers and 5.2% for regenerators. The prediction results also appear similar with previous experiment data, showing errors of less than 10%. The solution temperature has the greatest impact on moisture effectiveness and removal rate of internally cooled/heated liquid desiccant dehumidification system. Air humidity, air flow rate, solution concentration, and solution flow rate also significantly influence the system performance. Considering the limitations of practical projects, two more simplified equations with lower but acceptable accuracy were developed. This prediction method is very useful for researches and practical applications concerning the dynamic system performance.