Energy and Buildings 54 (2012) 243–251 Contents lists available at SciVerse ScienceDirect Energy and Buildings j ourna l ho me p age: www.elsevier.com/locate/enbuild An integrated simulation method for building energy performance assessment in urban environments Xiaoshan Yang a,b , Lihua Zhao a,∗ , Michael Bruse b , Qinglin Meng a a Building Environment and Energy Laboratory (BEEL), State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, China b Environmental Modelling Group (EMG), Johannes Gutenberg-Universität Mainz, Mainz, Germany a r t i c l e i n f o Article history: Received 22 November 2011 Received in revised form 5 July 2012 Accepted 18 July 2012 Keywords: Energy simulation Microclimate Integration Urban planning Building design a b s t r a c t The microclimate around a building, establishing through the interaction with other buildings or the natural environment, is a significant factor in the building energy consumption. This paper presents a method for the quantitative analysis of building energy performance under any given urban contexts by linking the microclimate model ENVI-met to the building energy simulation (BES) program EnergyPlus. The full microclimatic factors such as solar radiation, long wave radiation, air temperature, air humidity, and wind speed have been considered in the proposed scheme. A case study has been conducted to analyze the effects of different microclimatic factors on the energy balance of an individual building. The method outlined in this paper could be useful for urban planning and building design. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Building thermal performance and its energy consumption are affected by the energy exchange processes taking place between the outer skin of the building and the surrounding environments. A number of building energy simulation (BES) programs are capable of modelling building systems in detail (such as building geome- try, construction, indoor environment, infiltration, ventilation, and HVAC system) and analyzing building energy performance in a dynamic model. Nonetheless, the outdoor meteorological bound- ary conditions adopted in such tools are usually derived from the long-term observations of the local weather station. These data series are usually smoothed and averaged or even entirely based on statistics, which ignore the modifying effect of the surroundings. On the other hand, microclimate simulation tools offer the possi- bility for small-scale climate predictions with respect to different urban configurations. However, the features and the thermal pro- cesses of buildings are either simplified or totally neglected in these models. Therefore, the integration of the two kinds of programs could be a possible solution to achieve the quantitative evalua- tion of the microclimate effects on building thermal behaviour and energy use. Some previous studies have attempted to integrate different numerical tools to assess the effect of local climate on building energy performance. He et al. [1] developed a 3D-CAD integrated ∗ Corresponding author. Tel.: +86 20 87112275; fax: +86 20 87112275. E-mail address: lhzhao@scut.edu.cn (L. Zhao). system to simulate the interaction between indoor and outdoor thermal environment. It was based on the assumption of homoge- nous distribution of ambient air temperature and wind velocity. Flor et al. [2] reported an estimation method to evaluate build- ing energy requirements for a given urban context by using the outputs of an urban canyon model as the inputs of a building ther- mal simulation program. Bouyer et al. [3] established a coupling simulation platform for building energy evaluation in an urban con- text by integrating a home developed thermoradiative code into the commercial computational fluid dynamics (CFD) software Flu- ent. However, there was no investigation to integrate the existing urban microclimate models with the sophisticated building energy simulation tools. In this study, we established an integrated simulation system for building energy assessment in urban environments based on three programs: the urban microclimate model ENVI-met [4], the building energy software EnergyPlus [5] and the coupling platform Building Controls Virtual Test Bed (BCTVB) [6]. All the three pro- grams are freeware and available online. The ENVI-met model is used for the outdoor thermal environment prediction with respect to various urban configurations. The software BCTVB is used for developing a coupling module to transfer the simulation results of ENVI-met into the EnergyPlus model. The hourly 3D distribu- tions of the microclimate such as air temperature, air humidity, wind field, and ambient surface temperature are extracted from the ENVI-met simulation results and then taken as the outside bound- ary conditions of the EnergyPlus model. Through this method, the microclimate effects on building energy performance can be incor- porated into the EnergyPlus simulation. A case study has been 0378-7788/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.enbuild.2012.07.042