Hadi Ahmadi Moghaddam; Ramez Raja; Guan Heng Yeoh; Christophe Ménézo; Victoria Timchenko · 10.1016/j.energy.2025.137295 https://doi.org/10.1016/j.energy.2025.137295
Energy
Experimental analysis of natural convection in a building-integrated solar chimney- part 2: High surface emissivity Hadi Ahmadi Moghaddam; Ramez Raja; Guan Heng Yeoh; Christophe Menezo; Victoria Timchenko Solar chimneys have emerged as an effective passive ventilation system, using natural convection to enhance air circulation without mechanical assistance. The study focuses on a reduced-scaled vertical chimney coupled with a room, simulating a building-integrated SC. Two configurations were analysed: high emissivity on the active (heated) wall (HL case) and high emissivity on both active and passive (unheated) walls (HH case), compared to the low-emissivity case (LL case) from Part 1. Using Particle Image Velocimetry and thermal measurements under two heat flux conditions (110 W/m2 and 235 W/m2), the results show that higher emissivity improves radiative and convective heat transfer, reduces temperature differences between the walls, and enhances ventilation rates. The increased emissivity in the HH case resulted in a significant rise in the passive wall mean temperature by up to 9.2°C under higher heat flux. Additionally, changing surface emissivity significantly affects velocity distribution. In the HH case, increased emissivity led to more uniform vertical velocity profiles due to the contribution of passive wall to generation of buoyant flow inside the chimney and reduced the size of recirculation zone generated in chimney’s corner. Overall, the HH configuration demonstrated the best performance, with air changes per hour (ACH) increasing by 26%.
Building ventilation
Experimental
2025
Energy
no
2025-06-26 12:00:00 00002003
experimental analysis of natural convection in a building-integrated solar chimney- part 2: high surface emissivity
2025
Energy
Hadi Ahmadi Moghaddam; Ramez Raja; Guan Heng Yeoh; Christophe Ménézo; Victoria Timchenko
10.1016/j.energy.2025.137295
Abstract
Solar chimneys have emerged as an effective passive ventilation system, using natural convection to enhance air circulation without mechanical assistance. The study focuses on a reduced-scaled vertical chimney coupled with a room, simulating a building-integrated SC. Two configurations were analysed: high emissivity on the active (heated) wall (HL case) and high emissivity on both active and passive (unheated) walls (HH case), compared to the low-emissivity case (LL case) from Part 1. Using Particle Image Velocimetry and thermal measurements under two heat flux conditions (110 W/m2 and 235 W/m2), the results show that higher emissivity improves radiative and convective heat transfer, reduces temperature differences between the walls, and enhances ventilation rates. The increased emissivity in the HH case resulted in a significant rise in the passive wall mean temperature by up to 9.2°C under higher heat flux. Additionally, changing surface emissivity significantly affects velocity distribution. In the HH case, increased emissivity led to more uniform vertical velocity profiles due to the contribution of passive wall to generation of buoyant flow inside the chimney and reduced the size of recirculation zone generated in chimney’s corner. Overall, the HH configuration demonstrated the best performance, with air changes per hour (ACH) increasing by 26%.
Abstract by the authors, reproduced under the CC BY 4.0 licence. Original publication via the link below.
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