Thermal effectiveness of wind-tower with heated exit-wall and inlet-air humidification: Effects of winter and summertime

• Published in: Building and environment 2021-10, Vol.204, p.108110, Article 108110
• Main Authors: Morales, X., Sierra-Espinosa, F.Z., Moya, S.L., Carrillo, F.
• Format: Article
• Language: English
• Subjects: Air flow; Air humidification; Air temperature; Arid climates; Aridity; Climate change; Droplets; Fluid flow; Humidification; Low speed wind tunnels; Nu-Re correlation; Parallel plates; Plate heat exchangers; Residential buildings; Residential comfort; Reynolds number; Semiarid climates; Solar heating; Solar radiation; Streams; Summer; Water drops; Weather; Wind effects; Wind tunnels; Wind-tower building; Wind-tower heat transfer; Winter
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2021.108110

Wind-towers provide natural ventilation to residential building in hot arid and semi-arid climate. Water-droplet spray can reduce the air-stream temperature at air-inlet section to increase wind-tower effectiveness. However, temperature and humidity weather conditions due to climate change throughout the year play a main role. Besides, heating of building's structure produced by solar radiation has an impact on interior air-stream temperature. This paper presents a thermal assessment of combined wind-tower air-humidification with a heated wall under the effect of winter and summertime. A correlation Nusselt-Reynolds numbers for different weather conditions was developed experimentally, which investigates thermally a simulated solar heating of an exit-wall wind-tower-building by means of a parallel plate heat exchanger tested in a low-speed wind tunnel. The effect of a water-droplet spray on the wind-tower streams and constant heating exit-wall of the building was investigated varying the air-inlet Re number between 1.3x104 and 2.5x104. The results show that Nu number increases with Re number for both dry-air and moist-air flow wind-tower-building inlet condition. Wind-tower thermal effectiveness is 11.6% higher for summertime compared to the wintertime. Results for dry-air and moist air and the Nu-Re correlation can be used as guidelines for future wind-tower designs. •Wind-tower-building aided with air humidification is analyzed as a heat exchanger.•A Nu-Re correlation to wind tower dry-air/moist air flow is developed.•Humid air provides 16.4% thermal comfort in summer.•A model for wind-tower-building thermal effectiveness is presented.