Study of the natural convection phenomena inside a wall solar chimney with one wall adiabatic and one wall under a heat flux

• Published in: Applied thermal engineering 2007-09, Vol.27 (13), p.2266-2275
• Main Authors: Bacharoudis, Evangellos, Vrachopoulos, Michalis Gr, Koukou, Maria K., Margaris, Dionysios, Filios, Andronikos E., Mavrommatis, Stamatis A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buoyancy; Energy; Equipments, installations and applications; Exact sciences and technology; Experiment; Heat transfer; Natural energy; Simulation; Solar energy; Solar thermal conversion; Wall solar chimney
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2007.01.021

Four wall solar chimneys have been constructed and put at each wall and orientation of a small-scale test room so as to be used for the evaluation and measurement of their thermal behavior and the certification of their efficiency. At this stage, research focuses on the study of the buoyancy-driven flow field and heat transfer inside them. A numerical investigation of the thermo-fluid phenomena that take place inside the wall solar chimneys is performed and the governing elliptic equations are solved in a two-dimensional domain using a control volume method. The flow is turbulent and six different turbulence models have been tested to this study. As the realizable k– ε model is likely to provide superior performance for flows boundary layers under strong adverse pressure gradients, it has been selected to be used in the simulations. This is also confirmed by comparing with the experimental results. Predicted velocity and temperature profiles are presented for different locations, near the inlet, at different heights and near the outlet of the channel and they are as expected by theory. Important parameters such as average Nusselt number are also compared and calculated at several grid resolutions. The developed model is general and it can be easily customised to describe various solar chimney’s conditions, aspect ratios, etc. The results from the application of the model will support the effective set-up of the next configurations of the system.