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

Abstract

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 10.1% higher for wintertime compared to the summertime. Results for dry-air and moist air and the Nu-Re correlation can be used as guidelines for future wind-tower designs.