English

CSTB has built an experimental house MARIA: Mechanised house for Advanced Research on Indoor Air. The house is dedicated to study pollutants transfers, test ventilation systems, settle field investigation methods, and validate computational models. MARIA will be instrumented and automated according to pre-established scenario of operation reproducing parameters related to human presence and behaviour. The human presence is simulated with heat load and water vapour and pollutants emission. The operation of equipments such as doors and windows, domestic devices, will be automated.

In January 2002, a new European project named HOPE (Health Optimisation Protocol for Energy-efficient Buildings) started with 14 participants from nine European countries. The final goal of the project is to provide the means to increase the number of energy-efficient buildings that are at the same time healthy, thus decreasing the energy use by buildings, and consequently, resulting in a reduction of CO2 emissions from primary energy used for ventilation, heating and humidity control.

In addressing the goals of energy-efficiency and indoor air quality (IAQ) in homes, industry teams in the U.S. Department of Energy's Building America program are installing mechanical ventilation systems in tight homes. A variety of designs - some simple and inexpensive, some more sophisticated - have been demonstrated. The advanced designs provide more consistent ventilation over time, more uniform ventilation among rooms, and source control measures that reduce the air-change requirement.

The basic mechanism for natural ventilation in a building involves air flowing through purpose-made ventilator openings. These ventilators must be carefully designed as natural ventilation driving forces are weak compared to the dynamic forces created by mechanical systems. This paper describes a series of experimental parametric studies that investigated how components within a ventilator (in this case louvers and wire mesh screens) interacted. Airflow measurements through the individual louver and mesh components were compared to the airflow through mesh / louver combinations.

This study was aimed to analyse the ventilation efficiency and indoor air quality in the conventional kitchens, when porous screens were installed on the transoms. Numerical simulations and laboratory full-scale experiments were carried out in the model kitchen in the Department of Architecture at National Cheng-Kung University. The influences of porous screens on the temperature fields, flow structures and ventilation rates were indicated. The "Tracer-gas Concentration Decay" method was conducted to measure the air exchange rate and the age of air in the model kitchen.

Although most of the apartments adopt state-of-the-art convenience facilities, since they have become the most popular housing type in Korea, they depend on natural ventilation for HVAC systems, as traditional floor heating systems (Ondol) are used. On the other hand, the indoor environments of the apartments have become more important, because people stay longer in a room and the room environment is polluted, because of various kinds of interior materials. Accordingly, some apartments apply air conditioning systems using AHU and ventilation systems using heat exchangers.

The paper presents the effects of airflow access points on the passive modification of indoor air temperature in a partly roofed high-mass courtyard building found in moderate climate of southeast Queensland. Results of a field investigation reveal that despite sufficient shading within the courtyard, its air temperature and thus comfort levels depend greatly on the location of airflow access points in the building layout and section.

Increasingly, European building designers have used natural ventilation to control air quality and cool commercial buildings to conserve energy compared to mechanical cooling and fan operation. These advanced natural and hybrid ventilation systems may be adapted to the North American context, but work is needed including consideration of the broader diversity of climates. An approach to the analysis of climate suitability is presented and applied to a number of North American climates.

As part of a graduation research, six case studies were carried out to assess the validity of 10 often heard assumed disadvantages of natural ventilation in offices, including poor IAQ and thermal discomfort. The case studies included a methodic comparison of six buildings based on literature, interviews, field measurements and re-analysis of reports by others. Thus the preconditions for natural ventilation of office buildings and the most important design features could be determined in order to meet the performance standards as in use in the Netherlands.

The potential for natural ventilation is the rating of the possibility to achieve a good indoor air quality by natural ventilation only. The potential for passive cooling can also be defined. These potentials depend on site and building and are based on several parameters. Example of determination in Geneva area is given.