A Study on Applying Solar Chimney and Trombe Wall to a Building of Natural Ventilation

• Main Authors: Jhin-Yong Wang, 王智勇
• Other Authors: Yi-Jiun Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/40376640371996017110

碩士 === 國立臺灣科技大學 === 機械工程系 === 97 === This research uses Computational Fluid Dynamics (CFD) program, Flovent, to analyze buoyancy ventilation effect in a three-story building with a solar chimney and a Trombe wall. In this study ambient parameters and building physical parameters are varied to analyze the change of natural ventilation efficiency. The analyzed parameters include solar time (at the same solar day), Trombe wall materials (Aluminum, Brick and Fiber glass) and transmittance of glass in the solar chimney. CFD program uses the finite volume method and standard two-equation k-E turbulence model to calculate air flow and temperature distribution in the building. According to the simulation results of different Trombe wall materials, when the material of the wall is Fiber glass, walls can absorb solar radiation in them and provide heat energy to indoor air. Main buoyancy driven force of indoor ventilation is from heating walls. Buoyancy effect of solar chimney is weaker than heating walls. Therefore solar chimney with Trombe wall does not have significant effect on indoor ventilation. For the glass transmittance, this series of simulation has similar results. The construction configuration is not symmetrical. The northern room has a protrusive square part to the west, and the southern room is facing the sun directly at noon. The northern room is asymmetric to the sun at different solar time. At the same solar altitude angle the northern room has different indoor environment performance. When the wall is made of insulation material, the main buoyancy driven force of indoor ventilation is due to solar chimney. Indoor exchange flow rate increases when solar chimney with Trombe wall of higher specific heat and higher density. For higher transmittance of glass, indoor air receives more solar radiation, and that causes higher indoor exchange flow rate. The high absorption of glass can store heat inside itself to provide heat energy for indoor air.Indoor temperature does not vary much for different solar chimney glass properties when the wall is made of insulation material. Only the top of solar chimney has different temperature distribution for different values of transmittance and absorption. When the solar azimuth angle is different and the solar altitude angle is the same to solar chimney, the indoor exchange flow rate does not change a lot. When the solar time is at twelve o'clock, solar chimney glass receives the most solar radiation and indoor environment has the highest ventilation rate. The neutral level in solar chimney does not change much for the same wall material. When the wall is made of Fiber glass, buoyancy effect of heating wall is higher than that of solar chimney. Different Trombe wall and glass transmittance does not affect the indoor environment much,Only different solar radiation angle changes the properties of indoor environment. When the wall is made of insulation material, the buoyancy driven force is mainly due to solar chimney. Different building physical parameters and ambient parameter change indoor environment Performance.