IBPSA2015

A passive ventilation system using solar chimneys was designed to provide ventilation to several classrooms in an addition to an elementary school in Washington, DC. The primary design objectives were to provide enhanced indoor environmental quality and a learning opportunity for students. This paper explores the design process, describes obstacles faced in implementing the design, and presents the results of the simulations.

Validations of implicit large eddy simulation were carried about two wind tunnel studies, which are flow and dispersion measurements around the building. Conventional second order scheme was used in anticipation of using unstructured grid CFD code. From the first result ILES using a TVD scheme could represent an overall flow pattern around the building. From the second result, ILES using a TVD scheme could represent concentration almost within 15%.

Application of CFD (Computational Fluid Dynamics) toward performance-based building design has a long tradition. Increasingly, CFD tools are also being applied to address large-scale urban climatic questions. For instance, CFD-based analyses have the potential to provide a more detailed representation of the micro-climatic boundary conditions needed for building energy simulation. Likewise, CFD-based methods can be deployed to pursue queries pertaining to the contribution factors to the so-called Urban Heat Island effect.

This study prepares a list of articles on the CFD analyses of room air flow in the architecture field in Japan, and compiles information related to CFD analysis conditions described in each article. The discussion addresses trends in analytical conditions in Japan, the yearly transition of the number of cells, usefulness of the estimate formula for the number of cells of VDI 6019, and a rough guideline for number of cells for a low Reynolds Number model.

Natural ventilation is considered an energy efficient measure that can utilize outdoor cool air to achieve free cooling but needs not consume any fan energy. For studying the energy saving potentials of natural ventilation in factory building with design scheme, the building annual energy consumption simulation software DeST Vent+ was used to simulate the cooling load saving potential and fresh outdoor air flow rates of different area of window opening and ventilation shaft to decide the optimal design of opening area.

Diffuse ceiling ventilation uses perforations in the suspended ceiling to deliver air into the occupied zone. Due to the complex geometry of the diffuser, it is not possible to build an exact geometrical model in CFD simulation. Two numerical models are proposed in this study, one is a simplified geometrical model and the other is a porous media model. The numerical models are validated by the full-scale experimental studies in a climate chamber.

The project is a design for a mixed mode system using either cross flow or stack effect natural ventilation with ceiling mounted fan coil units, in the 42,000m2 British International College campus in Yangon, Myanmar, designed by Tangram Architects in collaboration with Terrell Group Engineering. The engineering design process uses numerical models combining a commercial CFD code, Urbawind, with a dynamic thermal simulation program, Energy Plus.

This study introduces a hybrid ventilation (HBV) system in a pig house combining natural and partial pit mechanical ventilation (PPMV). The PPMV system is installed below the slatted floor with the capacity of 30% of the maximum ventilation rate. The proposed PPMV system can collect highly concentrated air and clean it in an economic approach so that odour emissions are abated.

This study investigates the effect of modeling the slatted floor as porous media on prediction of ammonia emissions and airflow patterns. Two approaches to determine the resistance coefficients of porous media modeling are adopted by using two geometries in CFD modeling. The results reveal that the ammonia emission with slatted floor modeled as actual size (SLM) is generally lower than the value with floor modeled as porous media (POM). Difference of air speed distribution close to the floor is also found between SLM and POM.