Natural ventilation by windexchangers in a building with a window in prevailing winds: design guidelines

Natural ventilation of an isolated generic building with a windward window and different windexchangers: CFD validation, sensitivity study and performance analysis

“…A windexchanger (WE) is a relatively small structure located on the building rooftop to promote natural ventilation (Cruz-Salas et al 2014). This structure is more commonly referred into the literature as windcatcher, but the term windexchanger accounts for the fact that this structure can act either as an injector or as an extractor of air depending on the orientation when the building has another opening in one of the facades (Su et al 2008;Liu et al 2011;Cruz-Salas et al 2014;Castillo et al 2017) or can act simultaneously as an injector and extractor when it has no other opening (Elmualim and Awbi 2002;Elmualim 2006a;Li and Mak 2007;Su et al 2008). A WE can be a suitable alternative to increase natural ventilation when the construction area or surrounding buildings impose limitations to use crossventilation by two windows, one at the windward and the other at the leeward facade (Karava et al 2011;Etheridge 2012;Bangalee et al 2013;Shetabivash 2015;Carrilho da Graça et al 2015;Perén et al 2015a).…”

“…More than 70% of the geographical area of Mexico has a hot climate, and most of the dwellings that are being constructed in Mexico have one or two floors, with only one opening per room. In general, the construction area imposes limitations in increasing the ventilation by two windows in opposite walls of a room, thus the use of a windexchanger on the roof of these dwellings has been proposed to increase natural ventilation (Cruz-Salas et al 2014, 2018Castillo et al 2017). Building geometries and wind conditions have to be investigated in order to provide guidelines for the design of WEs that promote an airflow distribution that is as uniform as possible within the living zone of a building and a sufficiently high airflow rate.…”

“…windows, in the building and the wind conditions, i.e. speed and direction (Montazeri et al 2010;Cruz-Salas et al 2014;Castillo et al 2017) and the internal arrangements in the building, such as window louvers, furniture, etc. Experiments are an important methodology for WE performance assessment, but using this method can be a slow and tiresome process when parametric analyses need to be performed.…”

“…An often studied WE geometry is that with a square cross-section and four subducts (Elmualim and Awbi 2002;Elmualim 2006a,b;Li and Mak 2007;Ghani 2009, 2010;Liu et al 2011;Cruz-Salas et al 2014;Khodakarami and Aboseba 2015;Castillo et al 2017), and most of the existing commercial WE have this geometry (Hughes et al 2012). A similar WE with circular cross-section and four subducts has also been studied (Elmualim and Awbi 2002;Su et al 2008;Montazeri 2011).…”

“…A similar WE with circular cross-section and four subducts has also been studied (Elmualim and Awbi 2002;Su et al 2008;Montazeri 2011). In addition, square or rectangular cross-section WEs with one duct (one-sided) (Montazeri and Azizian 2008;Montazeri et al 2010;Esfeh et al 2012;Cruz-Salas et al 2014;Calautit et al 2015;Castillo et al 2017) and two subducts (two-sided) (Montazeri et al 2010;Cruz-Salas et al 2014;Castillo et al 2017) have been analyzed, as well as circular cross-section WEs with two, three, six and twelve subducts (Montazeri 2011). When comparing a square or rectangular cross-section WE, in the same conditions with a circular cross-section WE, having the same subducts number, it was found that the square or the rectangular one provides a higher airflow rate than that with a circular cross-section (Elmualim and Awbi 2002;Montazeri 2011).…”