English

Fresh air is one of the most important affecting factors for air conditioning system. On one hand, it contributes to good indoor air quality (IAQ). On the other hand, it partly determines the energy consumption of air conditioning system. This paper focuses on the study of IAQ based demand controlled ventilation (DCV) in which CO2 concentration is used as the controlling index of human produced contamination due to the fact that human beings is the main source of indoor CO2, and TVOC concentration is used as the controlling index of building produced contamination.

Positive building pressure with respect to outdoors has been shown to be a positive step to reduce the likelihood of wall moisture problems in hot, humid climates. Exterior wall moisture problems usually result in microbial growth, reducing the health of the building as well as structural degradation of the wall components. However, the test instruments, procedures and reporting methodologies are not provided or recognized in the building design and construction community.

The objective of the paper is to compare central and decentralized air-handling units with regard to costs and suitability. It is mainly based on a calculation model for Life Cycle Costs (LCC), which has been used on two cases, one high-rise and one medium-rise office building. Qualitative evaluation of non-quantifiable factors supports the comparison. The results show that the decentralized solution in general has higher LCC, but buildings with side wings and fewer floors tends to even out the differences.

We present the experimental and numerical study of a plume developed above a heat source both in a stratified and non-stratified medium. This situation arises in industrial facilities with displacement ventilation where air is supplied to the lower zone and extracted at roof level.

This study reports generally low actual air change rates in Finnish houses. Average air change rates in winter were 0.3 ach (11 l/s,pers) in natural, 0.34 ach (10 l/s,pers) in mechanical exhaust and 0.41 ach (13 l/s,pers) in mechanical supply and exhaust ventilation. The prevalence of indoor climate related complaints was lowest within an air change range of 0.3...0.5 ach. At lower air change the prevalence of odors and at higher air change the prevalence of draft and dry air was significantly higher.

The Air Infiltration and Ventilation Centre is operated under Annex V of the Energy Conservation in Buildings and Community Systems implementing agreement of the International Energy Agency. The primary objective of the AIVC is to provide a high quality international technical and information forum covering the areas of ventilation and air infiltration in the built environment with respect to efficient energy use, good indoor air quality and thermal comfort.

Efforts to develop an international standard in the area of Building Environmental Design started in 1994 under the auspices of ISO TC 205. As part of the overall standard, Working Group 4 (IAQ) has developed a standard which covers methods of expressing IAQ and incorporating the goal of achieving good IAQ in the design process.

As part of the European research project HOPE (Health Optimisation Protocol of Energy efficient buildings), a comparison is made of the indoor environment in office buildings perceived as either healthy or less healthy. The aim is to characterise the differences between energy efficient buildings perceived healthy and energy efficient buildings perceived unhealthy. In 5 European countries, a pair-wise comparison of a healthy building and an unhealthy office has been made. The selection of the buildings was based on the results of an occupant questionnaire survey.

Within the European research project HOPE, 64 office buildings were audited regarding in-door environment quality and building characteristics. Of those buildings, two groups are se-lected: 21 buildings with low prevalence of the sick building syndrome, and 21 buildings with the largest prevalence. However, none of these buildings was considered a priori as sick. Both groups are similar for age of occupants, type of work, ownership, external environment, outdoor temperature, orientation, and smoking policy.

Experience shows that there are differences between the design and the real load of ventilation systems. Consequently, the fresh air demand usually varies over a wide range during operation. In normal usage, different types of gaseous contaminants enter the air, that might be hazardous to health. The constant inhalation of contaminated indoor air might lead discomfort or to harmful physiological effects.