Numerical-experimental investigation of a wind tower-room sustainable system: A parametric analysis of the mixed convection with humidification

Abstract

The wind tower is a sustainable architectural solution designed to improve natural ventilation and thermal comfort in buildings while reducing energy consumption. This study examines thermal comfort, natural ventilation, and heat transfer in a wind tower-room system with air humidification, such that the interaction of mixed convection with these parameters can be linked. The performance of the system is evaluated considering both natural and forced convection, influenced by differential heating and air inlet through the tower, respectively. A parametric analysis explores various parameters like outside air temperature, humidity, and velocity, along with room wall temperatures. Reynolds and Grashof numbers range from 8.57 × 103-1.99 × 105 and 2.20 × 109-1.31 × 1010, respectively. Simulations are validated against experimental data, with deviations under 5.0 %, 10.0 %, and 19.6 % for dry-bulb temperature, wet-bulb temperature, and air velocity. The system shows improved heat extraction efficiency under dominant forced convection conditions. Humidification yields PPD values between 10.0 % and 46.0 % and PMV values below 0 at air temperatures range 25.0–30.0 °C. At air temperatures of 35.0 °C with air humidity below 40.0 %, PPD values remain below 20.0 %. However, above 40 % humidity, humidification is less effective. The air exchange effectiveness reduction due to humidification is minimal at 0.61 %. These results illustrate the combination of parameters necessary for the optimal performance of the tower-room system, this study provides a valuable guide for integrating wind towers with humidification systems in building design and contributing to reduced electricity use and CO2 emissions.