Macroscopic parameters investigation and transfer characteristics assessment of counter flow packed tower liquid desiccant dehumidifier/regenerator

In this study, a simplified thermal model is developed for coupled heat and mass transfer processes in a packed tower counter flow adiabatic dehumidifier and regenerator. The developed differential energy and mass conservation equations are simplified to first-order linear differential form and solved using the boundary value problem to predict the macroscopic parameters at the outlet of the dehumidifier/regenerator. Total sixty-nine cases provided in the literature are validated using the developed model for adiabatic dehumidifier/regenerator and observed very good agreement with the average absolute deviation of ± 1.47%, ± 2.94%, ± 1.81%, and ± 4.77%, ± 4.05%, and ± 1.80% for macroscopic parameters such as air outlet temperature, liquid desiccant outlet temperature, and air outlet humidity ratio for dehumidifier and regenerator, respectively. Later, a parametric analysis is carried out to assess the sensitivity of the developed model with the variation in four inlet parametric variances such as air inlet temperature, air inlet specific humidity ratio, and L/G (liquid desiccant/air flow rate) ratio, and desiccant inlet temperature. It is found that air inlet specific humidity ratio, L/G ratio, and liquid desiccant inlet temperature each have a significant influence on tower performance. Furthermore, using the developed model a case study is conducted to analyse the macroscopic parameter characteristic distribution along with the height of the dehumidifier and regenerator. The distinct performance evaluation indices such as dimensionless heat and moisture difference ratio, latent heat ratio, and overall energy exchange in dehumidifier/regenerator along with tower height as performance evaluation parameters were introduced and variation with tower height are evaluated.