English

Tracer gas measurements are commonly used to estimate the fresh air exchange rate in a room or building. Published tracer decay methods account for fresh air supply, infiltration, and leaks in ductwork. However, the time delay associated with a ventilation system recirculating tracer back to the room also affects the decay rate. We present an analytical study of tracer gas decay in a well-mixed, mechanically-ventilated room with recirculation.

The research was oriented to analyze better the ventilation systems, in terms of cost-to-quality ratio. The matter of the paper is that a ventilation system is designed to work in certain quality conditions, but every quality has its cost. This cost comprises investment, energy consumption and operation-maintenance expenditures.

A three-dimensional drift-flux model combined with the deposition boundary conditions for wall surfaces in ventilated rooms are presented to study the particle dispersion in displacement ventilation rooms. Three ventilating air flow rates, 2 ACH, 5 ACH, 8 ACH and several particle sizes, 1, 2.5, 5, 7.5, 10 micron, are investigated. The results show that the particle dispersion characteristics are very different in displacement ventilated rooms with different air supply volume. In rooms with the same air supply volume, large-diameter particles diffuse more widely than small ones.

This paper reports experimental study of air quality in the kitchen of the CSTB experimental house MARIA. These experiments are transition between measurements in an experimental cell and in situ measurements. Indeed, ventilation conditions are controlled via either a hood or via a mechanical ventilation at the exhaust. The kitchen studied is also equipped with a pan on an electric cook-top which temperature is controlled. However, unlike measurements in test cells, wall temperatures cannot be controlled. Impact of cooking vapour on indoor air quality is analyzed using a tracer gas (SF6).

This study presents a critical analysis of assessment of ventilation systems effectiveness in terms of contaminant removal. For this purpose, experimental measurements are carried in a room of an experimental house called MARIA. Various ventilation scenarios are handled. The ventilated room is also equipped with a pine wood floor which emits several Volatile Organic Compounds which are considered as air pollutants here. Thereafter, based on boundary conditions given by measurements, Computational Fluid Dynamics (CFD) simulations are performed.

This paper presents the main results of a research on an individually controlled office environment. The research was carried out in a laboratory that counts on an air conditioning system with underfloor air supply and individual airflow control devices for personalized thermal comfort. The evaluation was based on quantitative and qualitative data acquired respectively by means of comfort variables local measurements and people participation. The main results refer to the thermal comfort parameters proper to the referred environment and parameters for the system operation.

The performance of two personalized ventilation systems combined with mixing or displacement ventilation was studied under different conditions in regard to thermal comfort of seated occupants. The cooling performance of personalized ventilation was found to be independent of room air distribution. Differences between the personalized air terminal devices were identified in terms of
the cooling distribution over the manikins body. The personalized ventilation supplying air from the

A distribution of contaminants from floor covering, exhaled air and human bioeffluents was examined in a mock-up of a typical two-person office by means of tracer-gases. The distribution was studied with two types of air terminal device for personalized ventilation combined with displacement ventilation. The results show that the type of personalized ventilation and its use affects the distribution of contaminants to a great extent, as does the type and location of contaminant sources.

Air exhaled by occupants may carry infectious agents and be one way of transmitting respiratory diseases in rooms. The exposure of occupants to exhaled air was examined at two different throw heights of underfloor ventilation combined with two types of personalized ventilation by means of full-scale experiments. The concentration of exhaled air from one occupant was measured in air inhaled by another occupant who used or did not use personalized ventilation.

For the application of personalized (PV) in practice, it is important to recognize its performance under realistic conditions as they apply in rooms. In this paper results of both CFD simulations and laboratory measurements are reported regarding the local ventilation effectiveness with personalized ventilation. It was observed that the personalized air influences only a limited microenvironment at the workstation. Then a new model was proposed to evalate the indoor air quality in the entire space with varied distributions of occupants.