IJV6

Night cooling is promoted worldwide as an effective tool to reduce refrigerative cooling demand. However it is clear that, as long as the potential for night cooling is not standardised and integrated into building energy performance calculations, its application will be strongly hampered. In this paper the practical experiences of night cooling in an office located in Belgium are first discussed.

In France there is an increasing demand for energy efficient and environmentally friendly buildings of high thermal comfort. Balanced ventilation systems with heat recovery on the exhaust air and earth to air heat exchangers (EAHEX) are interesting techniques which can reduce the heating and cooling demand of buildings, and improve internal thermal comfort. A numerical study was carried out to evaluate the impact of these two systems on the energy performance and internal thermal comfort of a dwelling, with respect to the French climate characteristics.

The purpose of this work is to present a study of the indoor environmental conditions of an office which is fully occupied and naturally ventilated by window and door opening. In order to investigate the mechanisms controlling the indoor environmental conditions, as well as the processes acting indoors, the CFD model PHOENICS and the numerical mass balance Multi-chamber Indoor Air Quality model (MIAQ) were applied. Model inputs were based on input data obtained from extensive experimental measurements that took place in the office.

Sustainable architecture design for tropical climates requires the use of natural ventilation combined with other strategies including: the use of appropriate materials, site location, orientation of faades and solar shading, etc. Requirements for thermal performance and indoor thermal comfort also depend on the geographical site where the building is located. The new Brazilian standard Norma ABNT NBR 15220-3 has established seven bioclimatic zones and some architectural guidelines for low-income houses.

Cross ventilation to reduce cooling energy is one of the most important techniques for maintaining acomfortable indoor environment in hot and mild seasons. However, at present, it is difficult to design the indoor environment under cross ventilation because there is insufficient knowledge to evaluate the effect of cross ventilation quantitatively.

The present study investigates the effect of alteration in the building shape due to some common remodelling practice on the wind pressure differences delta-p for cross-ventilation of a semi-detached low-rise building using Computational Fluid Dynamics (CFD). A commercial code ANSYS CFX was employed to solve the flow governing equations. The standard k-e, renormalisation group (RNG) k-e and Shear Stress Transport (SST) turbulent models were adopted for comparison and the computed velocity was validated against full-scale measurement data.

Several studies have suggested that recommended ventilation rates are not being met within schools. However these studies have not included an evaluation of whether or not this failure might have an impact on pupil performance and learning outcome. The work reported here was designed as an initial investigation into this question. Using the Cognitive Drug Research computerised assessment battery to measure cognitive function, this study demonstrates that the attentional processes of school children are significantly slower when the level of CO2 in classrooms is high.

The present study is focused on the relation between wind speed and air temperature during the summer period over the greater Athens area. Specifically, hourly air temperature data, recorded at 27 stations, were studied for June, July, August and September between 1996 and 1998. These data were related to the corresponding mean hourly values of wind speed, which were measured by the National Observatory of Athens. A small increase in air temperature in relation to increasing wind speed was found for daytime and night-time periods.

Gas phase filters were installed within the air handling unit of a HVAC system feeding 100 % fresh(outdoor) air to an office building. The filter efficiency for ozone (O3) and nitrogen oxides (NO2 and NO) was measured continuously over a one year period as a function of time (filter's life) and outdoor air parameters (temperature and relative humidity). The results show that the filter efficiency varies with time and depends on the temperature and relative humidity of air.

The natural ventilation of a building, flanked by others forming urban canyons and driven by the combined forces of wind and thermal buoyancy, has been studied experimentally at small scale. The aim was to improve our understanding of the effect of the urban canyon geometry on passive building ventilation. The steady ventilation of an isolated building was observed to change dramatically, both in terms of the thermal stratification and airflow rate, when placed within the confines of urban canyons.