Impact of plate wettability on Indirect Evaporative Cooling systems wet-bulb effectiveness: Computational Fluid Dynamics modeling, experimental validation, and performance analysis

Indirect Evaporative Cooling (IEC) represents an emerging technology to address global warming challenges, as it leverages the enthalpy of vaporization of water for air conditioning, thus promoting energy savings. Studies in the literature have shown that a crucial factor in the design and modeling of IEC systems is the wettability of the plates, as it significantly influences performance. However, existing models either assume fully wetted plates or estimate wettability using data-driven approaches, which may reduce accuracy and generality of the numerical results under specific operating conditions. In order to overcome these limitations, a Computational Fluid Dynamics model, which uses experimental data on IEC recuperators plate wettability as input parameters, was developed and experimentally validated, showing average and maximum discrepancies of 3.2% and 6.2% for the product air outlet temperature, 3.7% and 6.7% for the working air outlet humidity ratio, 4.0% and 7.3% for the wet-bulb effectiveness, respectively. Following validation, a performance analysis was conducted, with the aim of evaluating the impact of plate wettability on system performance for three different commercial surfaces, both when clean and when covered with limescale deposits.