English

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. 

Mixed mode ventilation is an effective way to reduce energy consumption as well as improve thermal comfort. Presented here is an easy to implement method which uses both energy simulation in EnergyPlus and airflow simulation in CFD to estimate cooling energy savings potential from using mixed mode ventilation. The intention is to improve the accuracy of natural ventilation simulation by taking advantage of both algorithms. This paper focuses on one type of natural ventilation used in mixed mode; wind driven natural ventilation.

Building form is one of the most critical factors influencing natural ventilation potential in an urban context, and thus has a significant impact on building energy consumption. This paper describes a genetic algorithm based building form optimization methodology that could respond to urban wind environments and achieve the highest natural ventilation potential. To accomplish this goal, scripts in Rhino Grasshopper were developed. The scripts employed a CFD simulation program to evaluate the pressure distribution on the investigated building’s façades.

Minimum levels of attic ventilation have been required by residential building codes in the United States for years, but the precise attic temperature reductions of “poking holes in the roof” and corresponding energy impacts have rarely been robustly quantified. This study investigates electric energy and demand impacts from passive attic ventilation using field study measurements and building energy simulations for homes in the American Southwest.

The benefits and limitations of time-dependent and steady state computational fluid dynamics simulations when evaluating natural ventilation were explored in a naturally ventilated case study apartment in the Mediterranean. For wind driven flows, indoor air properties responded quickly (i.e. within 1-min) to changing outdoor conditions, except indoor air temperatures (up to 30-min). The outdoor air temperature variations could reverse the flow direction during buoyancy-driven ventilation.

In the frame of a multi-year EU project, the set of European Standards from 2006/7 to support the European Energy Performance of Buildings Directive (EPBD) is undergoing a revision. The majority of the standards describe calculation methods. Based on the experience with the first generation of the standards and on a EU research project investigating the application of the standards in the Member States, a rigorous set of requirements has been set up. This includes issues like unambiguity and software proofness.

Domestic Hot Water (DHW) production can account for a quarter of the energy consumed in UK dwellings and this proportion is likely to increase as the energy required for space heating reduces in order to achieve demand reduction targets. As the margins for improving the performance of heating system technologies diminish, the need for improving modelling accuracy and precision increases. Although studies have considered DHW use, there is a lack of reflection on the consumption and performance of systems in contemporary UK dwellings.