Evaporatively-cooled window driven by solar chimney to improve energy efficiency and thermal comfort in dry desert climate

• Published in: Energy and buildings 2017-03, Vol.139, p.755-761
• Main Authors: Hweij, Walid Abou, Touma, Albert Al, Ghali, Kamel, Ghaddar, Nesreen
• Format: Article
• Language: English
• Subjects: Climate; Computational fluid dynamics; Computer applications; Energy conservation; Energy consumption; Energy efficiency; Energy management; Evaporative cooler; Evaporative cooling; Fluid dynamics; Glazing performance; Hydrodynamics; Mathematical models; Office space; Power efficiency; Radiation asymmetry; Solar chimney; Solar chimneys; Temperature; Temperature effects; Thermal comfort; Three dimensional models; Windows & doors
• ISSN: 0378-7788; 1872-6178
• DOI: 10.1016/j.enbuild.2017.01.071

•Performance of an evaporatively-cooled window driven by solar chimney is studied in dry climate.•A system model was coupled to space CFD model to predict the window temperature and impact on comfort.•Significant drop in window temperature of 3–4°C was achieved under Riyadh climate conditions.•Overall thermal comfort improved with the use of the system with 10% energy savings at 14h and 17h.•Thermal comfort was 1.42 at 14h; 1.96 at 17h (scale: very uncomfortable at −4 to very comfortable at +4). This study investigates the performance of an evaporatively-cooled window driven by solar chimney attached to external façades for providing acceptable thermal comfort at low energy consumption in an office space. A validated simplified model of the novel system was coupled with a developed 3-D computational fluid dynamics (CFD) model of the office space to predict the space window outer surface temperature. The CFD model was then coupled with a validated bio-heat model that was integrated with Zhang model to predict local and overall thermal sensation and comfort. Two representative hours were selected mainly 14h and 17h for hot and dry climate conditions for a space located in Riyadh. The reported results showed significant improvement in overall thermal comfort when the novel system is used to reach a thermal comfort level of 1.42 at 14h and 1.96 at 17h using a comfort scale varying from very uncomfortable at −4 to very comfortable at +4. Energy savings reaching 10% were recorded during both hours.