English

Field tests and a model allowed to study contaminant concentrations in a single family home in California operating with natural ventilation or with one of six mechanical ventilation systems (cyclic or continuous, multi-point or single-point exhaust). Continuous ventilation appears to be better for contaminant levels control.

This study is an analysis of the advantages of two ventilation systems (exhaust mechanical ventilation, balanced mechanical ventilation with heat recovery) using the Negative Index approach, which is affected by life cycle cost and environmental impact. The balanced system appears to be a better choice (less environmental impact, better indoor air quality) even if its life cycle cost is higher.

Thermal mixing of two air streams (outdoor air flow and return air flow) with different temperatures and velocities was studied experimentally in a chamber as it exists inside air handling units, with different adjustments of parallel air dampers. Results show how and where the mixing occurs in the chamber. Indications about the influence of the air dampers adjustment on mixing effectiveness are given.

The study was to evaluate energy use of ventilation system with supply in corridors and exhaust in wet rooms. The field test protocol was to measure energy use one day with corridor supply ventilation on, one day off, for a range of different outdoor temperatures in winter. When corridor supply is on, the internal pressure changes (although always negative) and infiltrations are modified.

Three algorithms (steady-state, dynamic, proportional) for CO2-demand controlled ventilation, coupled with three methods for determining minimum air flow rates (Ashrae 62, CEN CR 1752, Polish standard) and three occupancy scenarios, have been analysed in a research project to promote such systems in Poland. Results show that not only algorithms, but also minimum flow rate requirements, influence the operation of the system.

Describes what could be the requirements of a European standard (not yet numbered) prepared by Technical Committee 156 (Working Group 7) of CEN (European Standardization Committee) about the calculation of energy requirements for buildings with room conditioning systems.

A CFD code has been used to design and optimize the ventilation system of a building dedicated to auto-racing (120 000 persons, 45 cars). The constraints are the dimensions of the building, the heat and pollutants due to cars, their high speed and the size of granstands. The article shows the interest of airflow modeling to study the complex ventilation system of such a building.

Three measuring techniques have been compared for evaluation of the surface duct level in ventilation ducts : vacuum test, gravimetric tape method, optical tape method. Measurements have been operated in 13 recent buildings in Helsinki using the three methods. The vacuum test gives similar values to the gravimetric tape method when air ducts show no residual oil from their manufacturing (average values 1.1 and 1.2 g/m2). With residual oil, vacuum test gives higher dust levels than gravimetric tape method. The optical tape method is the most easy to use on site.

Relationships between research about indoor and outdoor air quality are reviewed. The author mentions that outdoor air pollution has attached greater regulatory interest, although people spend more time indoors. The contribution of exposure to indoor pollutants is now more recognized but this increased consideration has little effect on regulations. Nevertheless, the author considers that indoor air quality researchers and public health officials have a lot to learn from the outdoor air quality experience, in fields such as exposure, dosimetry, health effects and risks, mixed exposures.

The coupled thermal/airflow simulation software CONTAM97R was used to evaluate the performance of a naturally ventilated office building recently build in Entschede (The Netherlands), for which detailed measurements results within the Natvent project had already been published.