Modelling natural convection in a heated vertical channel for room ventilation

Solar-air collectors installed on the south-facing walls of school building s have been tried out in Portugal as a passive means of improving indoor ai r quality without prejudice to thermal comfort requirements. A numerical in vestigation of the behaviour of these systems, typified as vertical channel s opened at both ends, is presented for typical geometries and outdoor cond itions. The study is carried out with natural convection and assumes that t he induced flow is turbulent and two-dimensional. The fully averaged equati ons of motion and energy, added to a two-equation turbulence model, are dis cretized and solved following the concepts of TEF (Transfer Evolution Forma lism) using a finite volume method. Flow and temperature fields are produce d and results presented in terms of temperature and velocity distributions at the exit section of the duct. These enable a better understanding of the developing flow and can be helpful in the design phase of this type of sys tem. (C) 2000 Elsevier Science Ltd. All rights reserved.