Integrating Themro-Fluid Computational Models into Understanding Sustainable Building Design

Sustainable buildings demand a holistic approach towards the design ofspace, envelope, and environmental control systems; the construction materialsand occupational behavior. The goal of our research is to push wholebuilding performance evaluation and simulation to higher levels. This paperwill report on an interdisciplinary research endeavor coupling engineeringexpertise in computational fluid dynamics (CFD) with architectural designto build simulation expertise for designing natural ventilation strategies inbuildings. We utilize an operating solar powered home as a laboratory formodeling and testing. The building explores an efficient balance of passivedesign and active energy harvesting strategies. Energy measurements areavailable to verify simulations.Our research goal is to enhance the utilization of naturally occurring energyflows around buildings and through their interior spaces, within or aroundbuilding materials to achieve thermal comfort, individual control and airquality, while eliminating fossil fuel consumption and negative environmentalhealth impacts. We aim to achieve this goal by integrating CFD simulationand visualization tools into the design process. In particular we investigatethe relationship between spatial composition and natural air movementas free heating and cooling ventilation strategies by tightly coupling computationalfluid dynamics modeling and architectural design. A successfulimplementation of this research will significantly reduce the need for activemechanical systems in buildings and provide a holistic performance assessmentmodel, which will greatly enhance the acceptance of green technology.An in depth literature review was conducted to understand the current stateof the art of natural ventilation simulation and design identifying new researchquestions on the interaction of space, air movement and materialproperties. The project started by modeling whole building ventilation scenariosof wind and buoyancy driven natural flows with ANSYSFLUENT basedon representative studies. We then applied the knowledge to the case studyhouse and conducted a variety of scenario simulations and can now verifythe simulations with measurements on site.Firstly the importance of spatial composition for air movement is discussed,then are the boundary conditions established for buoyancy and wind driven airmovement, before solar radiation and energy transfer in air can be modeled.In the result section a first sample simulation for a sun space on a wintervarious seasonal days with direct irradiation and diffusion irradiation will bediscussed. Outside temperature and wind speed will be set and a variety ofwindows to the outside are opened and closed to understand the interactionbetween solar radiation and outside wind patterns. Thus these parametersand connections enable the convective passive solar air loop to start bringingsolar thermal energy into the main living space. The paper will discuss thesefirst results and their implications for natural ventilation design.

Volume Editors
Martha Thorne & Xavier Costa

ISBN
978-0-935502-83-1