Theoretical Study on Falling Film Fin-Tube Dehumidifier Integrated With an Evaporative Cooler

The current work presents the theoretical analysis of a falling film fin-tube dehumidifier integrated with an evaporative cooler using CaCl₂ as a liquid desiccant. In a fin-tube dehumidifier, the fins are provided outside the tubes to sustain the solution temperature during dehumidification. The evaporative cooler is compiled with a dehumidifier to provide cool air over the fins for maintaining the solution and air temperature. The theoretical model examines the heat and mass transfer between the air and the solution, which are moving in a counterflow direction inside the tubes. The study first presents the validation of the theoretical model with the experimental findings. The maximum disparity between theoretical and experimental results for moisture reduction with solution volume flowrate is found to be ±6.2%, whereas it is discovered to be ±13.8% for moisture reduction with airflow rate. The paper then discusses the air and solution parameters variation along the tube height and the impact of air and solution inlet parameters on system performance. The findings indicate that the variation in outlet air humidity ratio with tube height from 0 to 1 m is observed highest, 0.0264 kg/kg d. a. to 0.0233 kg/kg d. a., for a solution volume flowrate of 12.5 LPM and an airflow rate of 0.05 kg/s. The maximum variation in moisture effectiveness with tube height is observed from 0.0045 to 0.292 at 5 LPM solution volume flowrate and 0.05 kg/s airflow rate.