ventilation

This paper reports on an investigation of the use of an innovative earth tube ventilation system designed to improve the internal comfort conditions without the need for mechanical cooling. The numerical model and computer simulation developed for the prediction of air and soil temperatures has been made. The paper demonstrates the accuracy of this model and describes the results of analysis.

This paper presents a summary of calculations on the total cost effects of the remedial measures to reduce high summer time room temperatures in a hypothetical building. In the base case the room air temperature is too high during the summer, and causes a considerable reduction in the productivity. The following economical items are included in the study: first cost of the remedial measure, the effect of the measure in operating cost, particularly on energy consumption, and the effect on productivity.

The provision of a healthy and satisfactorily clean indoor environment requires that consideration be given to a range of issues, such as the type of indoor environment, indoor and outdoor sources, indoor activity and others. The selection of relevant measures to achieve the required indoor air quality (IAQ) depends on knowledge and understanding of the mechanisms and parameters affecting the concentration levels indoors.

Gas cooking in the home can release high levels of nitrogen dioxide (N02) and carbon monoxide (CO). This study investigated the effect of various ventilation strategies to reduce personal exposure to these pollutants. It considered the effectiveness of windows, a kitchen extract fan and trickle ventilators for different dwellings, occupant behaviour, environmental conditions etc. Strategy selection was based on the need to minimise both personal exposure and energy loss. These strategies were simulated using BRE's BREEZE multi-zonal computer code.

Epidemiological studies suggest that cooking with gas leads to an increase of air pollutants and may enhance symptoms of respiratory diseases. However, little experimental data are available concerning the emission of pollutants due to different cooking processes. The goal of this study was to investigate the influence of cooking under standardized conditions on the indoor air quality. A model kitchen was built and three different gas stoves and one electric stove were included in the study. Two different menus were prepared with different settings of the ventilation rate of the exhaust.

Air may be pre-cooled using thermal mass before it is supplied to an occupied space. One option is to pre-cool the air in a basement space and exhaust the air at high level through stacks. However, the thermal forces that determine the direction of airflow, including heat gains in the occupied space, thermal mass cooling and the external air temperature may counter each other, and result in flow reversal.

Adequate ventilation and good air quality are essential for the comfort of occupants and productivity. Excessive ventilation however, may result in discomfort and high energy loss. A study was carried out to examine the influence of ventilation on indoor thermal conditions. The results show that ventilation has profound effect on lowering the indoor temperature, particularly the night time ventilation. Derived PMV is compared with actual votes (thermal sensation) and found that PMV is lower than actual votes.

An intervention study in eleven schools with approximately 1000 children age twelve to thirteen has been carried out in the period 1997 to 1999. Four schools with poor ventilation standard, three schools with carpets and four reference schools participated. In the schools with carpets, these have been removed and in the schools with poor ventilation systems, these have been upgraded to Norwegian standards for new buildings. A questionnaire was answered three times during a two-week period, asking how indoor environment-related symptoms were perceived.

This paper presents a recent field measurement study undertaken in 1999 on 73 recent Frenchdwellings. The study presented the opportunity to assess the conformity and the performancesof the dwelling ventilation systems and to assess the impact of infiltration on airchange rates.The following aspects were analyzed : (1) the type of ventilation facilities in the dwellings ;(2) the defaults in the installed systems and in their operation ; and (3) the measured air flowrates, as compared to the French standard required levels.