Energy and Buildings 88 (2015) 57–67 1 Estimation of wind energy over roof of two perpendicular buildings B. Wang a,* , L.D. Cot b , L. Adolphe c , S. Geoffroy a , J. Morchain d a Université de Toulouse, UPS, INSA, LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, Avenue de Rangueil, 31077 Toulouse, France b Université de Toulouse, UPS, INSA, ISAE, ENSTIMAC, ICA (Institut Clément Ader), 3 rue Caroline Aigle, 31400 Toulouse CEDEX, France c Université de Toulouse, ENSA, LRA (Laboratoire de Recherche en Architecture), 83, Rue Aristide Maillol, BP 10629, 31106 Toulouse, France d UŶiǀeƌsitĠ de Toulouse, IN“A, LI“BP ;Laďoƌatoiƌe d’IŶgĠŶieƌie des “ystğŵes BiologiƋues et des PƌoĐĠdĠsͿ , 135, Avenue de Rangueil, 31077 Toulouse, France Abstract Wind energy development in a built up environment will be an important subject for future sustainable cities. Maturing CFD technology is making more wind flow simulation experiments available, which can be validated by in situ and wind tunnel measurements. Starting from research on wind accumulation by the Venturi effect in built environment, this paper tries to establish the relationship between wind energy potential and the configuration of two perpendicular buildings by performing parametric CFD wind tests. Two reference buildings (Width*Length* Height = 6m*15m*10m) forming a symmetrical corner are chosen and different building lengths, widths, heights, corner separation distances, angles of inlet and altitudes of assessment are considered. Results show that, in converging inlet mode, wind energy potential over the roof generally increases sensibly as the corner separation becomes larger, while in diverging inlet mode it decreases rather slowly with corner enlargement. Meanwhile, compared with a single, isolated reference building, most of the corner configuration cases studied here show greater wind energy density over the roof. Keywords Wind energy, CFD, built environment, building configuration. 1. Introduction Faced with environmental issues like depletion of resources, greenhouse gas emissions and the dramatic climate changes they cause, the as yet unfulfilled mission of developing green energy will be of increasing importance for future generations. Wind energy as one of the renewable energy sources is relatively cheap and available over great areas. Over the last fifteen years, the wind industry has shown an accumulative growth of around 28% [1]. However, as the windy areas remaining to be exploited are decreasing, and as energy demand is much less dynamic than energy production in such usually rural areas, the issue has been raised of avoiding great energy losses due to transportation by developing energy where it is to be consumed. In addition, the installation of small turbines in cities has also shown benefits like raising public awareness and the effects of pƌojeĐtiŶg a gƌeeŶ iŵage. In 1998, a European Commission project named WEB (Wind Energy for the Built Environment) was launched and a new architectural and aerodynamic model was invented as the prototype of UWECS (Urban Wind Energy Conversion Systems) [2]. Later, the UK looked into the feasibility of the BUWTs (Building Mounted / Integrated Wind Turbines) project in 2003 -2004 [3]. BUWTs and another European Commission project named WINEUR (Wind energy integration in the urban environment, from 2005 - 2007) were elected for more detailed investigation of wind energy development in an urban environment: suggestions for turbine installation, economic analysis and detection of potential social problems associated with the implementation of small wind generators in urban areas [4]. In a global view, IEA (International Energy Agency) has united 25 countries and organisations in the Task 27 project for the research of small wind energy development (small wind turbine labels development and deployment from 2008-2011, and small wind turbine in high turbulence sites from 2012-2016). Apart from that, some other research organizations also made efforts on urban wind- energy environment evaluation and micro-wind turbine trials in the built environment [5-8]. While the projects mentioned are oriented towards an overview of the real world situation (market, policy, social and economic aspects), other research has explored the technical domains such as turbine design [9-10] or numerical simulation of sites [11-14]. * Corresponding author. Tel.: +33 (0)7 87 27 64 46 E- mail address : bwang@insa-toulouse.fr (B. Wang)