Impact of building shape on thermal performance of office buildings in Kuwait Adnan AlAnzi a , Donghyun Seo b , Moncef Krarti b, * a Architectural Engineering Department, University of Kuwait, Kuwait City, Kuwait b Civil Environmental and Architectural Engineering Department, University of Colorado, Campus Box 428, Boulder, CO 80309, United States article info Article history: Received 13 February 2008 Accepted 12 September 2008 Available online 17 November 2008 Keywords: Building shape Cooling energy use Heating energy use Office buildings abstract This paper provides a simplified analysis method to estimate the impact of building shape on energy effi- ciency of office buildings in Kuwait. The method is based on results obtained from a comprehensive whole building energy simulation analysis. The analysis takes into account several building shapes and forms including rectangular, L-shape, U-shape, and H-shape as well as building aspect ratios, window- to-wall ratios, and glazing types. The simplified method is suitable for architects during preliminary design phase to assess the impact of shape on the energy efficiency of office buildings. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Some studies have shown that the building shape can have a significant impact on the energy costs of heating and cooling [1–3]. However, no general guidelines are available for architects and designers on the impact of the form on the energy efficiency of buildings. Recently, Ourghi et al. [4] have developed a simpli- fied analysis tool to predict the effect of shape selection on the annual energy use for office buildings. In particular, the method correlates the annual energy use to the relative compactness of the building. The relative compactness, a normalized ratio of the volume to the exterior wall area, is commonly used as indi- cator of shape in buildings. The method of Ourghi et al. has been developed for limited building shapes (rectangular and L-shapes) [4]. In this paper, the work of Ourghi et al. is extended to include several building shapes, window areas, glazing types. Using the re- sults of a comprehensive parametric analysis, a correlation is developed to predict the impact of building shape on energy effi- ciency for various window areas and glazing types. First, the basic settings for the parametric analysis, conducted using a detailed building energy simulation tool, are described. Then, selected re- sults of the parametric analysis are presented. Finally, the simpli- fied calculation method is developed to correlate annual energy use to building shape and window-to-wall ratio as well as glazing type. 2. Parametric analysis For the study presented in this paper, a prototypical Kuwaiti of- fice building is considered. The total office floor area for this proto- typical building is 12,500 m 2 distributed over 20 floors (625 m 2 / floor). 2.1. Building shapes Several shapes and floor plans have been developed for the prototypical office building. The floor plans include: Rectangular- shape, L-shape, T-shape, Cross-shape, H-shape, U-shape and Cut-shape shape. For an easier comparative analysis, the energy simulation results are normalized using the results obtained from a reference shape, which has a square floor plan with the same floor area (625 m 2 ) and number of floors (20 floors) as the proto- typical office building. In addition to the reference square floor plan, a ‘‘bounding rectangle” is defined for each floor plan. This bounding rectangle is defined by its width W, and depth D as shown in Table 1 for each shape. The floor area is kept constant for all shapes. To ensure that the conditioned building volume re- mains constant, the total height is kept the same for all building configurations throughout the study. Table 1 lists the geometric dimensions including the perimeter (P) and the relative compactness (RC) of the floor plans for all the building configurations used in this study. 2.2. Relative compactness The relative compactness (RC) is used in this study as an indica- tor of building shape to help the comparative analysis when 0196-8904/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.enconman.2008.09.033 * Corresponding author. Tel.: +1 303 492 3389; fax: +1 303 492 7317. E-mail address: krarti@colorado.edu (M. Krarti). Energy Conversion and Management 50 (2009) 822–828 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman