English

In this paper the effects of atrium and other similar architectural design features (e.g. shafts) on ventilation efficiency are examined in a multi-storey office building. Attention has been given to simulate the use of the main entrances, the vestibules and the various shafts. An atrium and an non atrium solution were compared for the examined building. Stack effect was the dominating force and wind effect was present yet not significant, but enough to produce negative pressures at the area of the atrium, mainly due to the form of the atriums roof.

Introduced for the first time at 25th AIVC Conference in Prague in September 2004, the HR-Ventproject still delivers new rich teachings since its start in January 2004. Until December 2005, morethan 700 million data have been recorded on 180 extract units in 5 occupied collective buildingslocated in NANGIS (France).

The commercial general - purpose Computational Fluid Dynamics (CFD) code PHOENICS is used to study the indoor environmental conditions of a large, mechanically ventilated, athletic hall. The indoor space of the building was simulated in the PHOENICS environment and computations were validated against experimental data obtained during a ten-day campaign in the hall. Data included measurements of airflow characteristics at different indoor locations under different ventilation conditions.

Combined heat, air and moisture (HAM) simulation at the envelope level and building simulation havebeen two separate activities for many decades now. In HAM-models, inside temperature and inside relative humidity are handled as known boundary condition, while all building simulation tools predict inside temperatures and net energy demand without any consideration for relative humidity.Things started to change when airflow modeling became doable.

Currently, various studies have demonstrated some doubt about the accuracy of the orifice equation when applied to the calculation of cross-ventilation. As a result, a computational fluid dynamic (CFD) simulation is considered the best method of analyzing cross-ventilation properties under present conditions. However, repetition of CFD analysis to determine the optimum ventilation performance is particularly complex. Accordingly, a flow network model that corresponds to cross-ventilation was developed and suggested as a more efficient means of determining the optimal opening conditions.

In 1998, Persily published a review of commercial and institutional building airtightness data that found significant levels of air leakage and debunked the myth of the airtight commercial building. This paper updates the earlier analysis for the United States by including data from over 100 additional buildings. The average airtightness of 28.4 m3/hm2 at 75 Pa is essentially the same as reported by Persily in 1998. This average airtightness is in the same range as that reported for typical U.S.

Studies on buildings’ airtightness have shown that several issues can arise from uncontrolled airflow leakages in buildings (e.g., higher energy cost, thermal comfort and health of occupants, building components and equipment preservation). The new French

In today’s architecture, innovative concepts, such as double skin facades, for the building skin are developed to improve the energy performance of a building and at the same time improve the indoor climate of the building. Various types of double façades

Ventilation in buildings is necessary first for hygienic reasons and also to preserve the building structure. This is more essential, today, because the buildings are more and more airtight, mainly due to energy regulations. It is also evident that air renewal energy losses and fan consumption become more and more important in relation with the total energy consumption of buildings. Nevertheless, many defaults are encountered on installed ventilation systems. It seems necessary to check the installations, at the starting up and regularly in time, and not only when the problems occur.

This field study was organized to determine the ventilation required to maintain acceptable air quality in a retail store using the ASHRAE Standard 62-1989 performance-based procedure. Pollutant concentrations and ventilation rates were measured in a large retail store during four one-week intervals. The measurement intervals were each separated by three months to allow different weather conditions and mixes of retail stock to be present over the one-year field study in a cold continental climate.