This paper deals with low Reynolds number jets for personalised ventilation and the possibility to control them in order to obtain useful modifications of the flow field, it can be done by simply adding a ring-like perturbation in front of the jet itself.
The paper presents the results of the measurement of turbulence intensity in jets issued into enclosures of different size. The test results confirm the relation between the velocity distribution coefficient and turbulence parameters.
The paper presents the results of experimental tests : the enclosure size and background turbulence in the surroundings of the jet have an influence on the air velocity distribution in axisymmetric jets
The aim was to develop a simple dynamic model for predicting air exchange caused by short time single-sided ventilation and necessary window opening time in classrooms. Tracer gas measurements have been made in a full-scale room. The comparison indicates that the model can be used when rough estimates of air exchange are of interest.
This paper presents a set of detailed experimental data of room airflow with displacement ventilation. These data were obtained from a new environmental test facility at the Massachusetts Institute of Technology (MIT). The measurements were conducted for three typical room configurations: a small office, a large office with partition, and a classroom. The experiment measured the distributions of air velocity, air velocity fluctuation, and air temperature by omnidirectional hot-sphere anemometers and contaminant concentrations by tracer gas at 54 points in the room.
An overview is given of the current position regarding the use of wind tunnel modelling and envelope flow theory for determining natural ventilation through large openings. The overview is, to a large extent, a personal one and is illustrated primarily by recent research carried out in Nottingham, some of which has yet to be published in full.
Climatisation and natural ventilation concepts are today, in most countries, considered to be an essential aspect of the building project. In fact they are utilised to guarantee summer thermal comfort and indoor air quality control. Also there are many other advantages including low energy use, reduction of noise levels and easy plant maintenance. In recent years the use of hybrid ventilation systems in office buildings has been developed. The achievement of thermal comfort conditions in buildings is an important aim in order to satisfy occupants.
This paper focuses on hybrid ventilation performance in an office building. It presents measurement results from the new headquarters of the company Bang & Olufsen, which served as one of the case study buildings in IEA ECBCS Annex 35. Ventilation and control strategy, as well as operational experience of the hybrid ventilation system is presented. Measurement results include long-term values of temperatures, CO2 and energy use for assisting fans and heating of ventilation air as well as electricity use for appliances.