air flow

Air temperature, air humidity and ventilation has been measured in a Swedish baroque castle. Results are presented for a measurement campaign comprising four periods under varying climatic conditions. A passive tracer gas method, known as the homogeneous emission technique has been used to measure the ventilation rates and air distribution in the building. As the palace is essentially unheated, wind pressure is the main driving force for ventilation. The air change rate is highly varying and differs considerably in different parts of the building (0.5-1.5 ACH).

The paper presents the results of the tests of two-zone airflow pattern forming in a room with displacement ventilation where various heat sources and various airflow rates were tested. The position of the interface layer between the zones was determined experimentally - on the basis of tracer gas concentration measurement and on the way of calculation - on the basis of the plume model above a point heat source complemented with experiment. The following heat sources were used: a plume simulator, a desk lamp, a computer, a round plate and a human body.

Recent years have brought the popularity of methods in which neutral networks are applied. They seem of particular importance while dealing with diagnosing, predicting and estimating. Those methods rely on collected data base, simulation and interpolation in the so-called learning process. There are attempts at neutral network application in building engineering. The paper sums up the initial phase of research on neural applications in the air exchange estimation.

Particle deposition from turbulent duct flow is modelled and related to particle penetration of a ventilation system for a commercial office building. Three published turbulent deposition models capable of accommodating surface roughness are compared to experimental data and used to determine the penetration of 0.1 - 10 (m spherical particles through a sample duct run. Depending on the model employed, penetration fractions varied from 0.40-0.94 for 0.1 (m particles and 0.28-0.73 for 10 (m particles.

This study is to investigate the characteristics of indoor air temperature distributions and airflow patterns with three air diffusing systems in heating period and to find the methods which can predict those indoor environmental conditions effectively. A series of measurements and corresponding numerical analysis were done. Selected three air diffusing systems for this study are as follows; 1) ceiling supply-ceiling exhaust, 2) ceiling supply-floor exhaust, 3) floor supply-ceiling exhaust.

The aim of this research is to apply dynamic Large Eddy Simulation (LES) to predicting the complex turbulent flow field in an air-conditioned room. LES is a method to calculate turbulent flows where only the small-scale (subgrid-scale) motions are modelled and the large-scale (grid-scale) motions are computed directly. Recently, a dynamic subgrid-scale model has been developed that can evaluate a model coefficient dynamically. This paper presents a numerical simulation of LES with a dynamic mixed subgrid-scale model of a flow field in an air-conditioned room model.

Scale model experiments give possibilities for analyses of the design conceptions of ventilation especially of air distribution in large enclosures. When simulating aerodynamic and thermal processes in scale models of room ventilation, the flow patterns are visualised and the air flow temperature and velocity are measured. The paper presents the results of experimental tests of the air mean velocity field in three different size models of the same ventilated room. The field maps of the air velocity mean value were analysed.

The objective of this research is to investigate thermal comfort and air flow distribution insidea test room which is naturally ventilated. The test room is ventilated through adjustablelouvers. The air pressures and velocities across the openings together with indoor airtemperature and mean velocity at four locations and six different levels are measured. Thecollected data are used to predict thermal comfort parameters across the test room. Tests werecarried out over the winter and summer time.

Air flow patterns in rooms can roughly be classified as one of three types: Displacement flow, source flow and mixed flow. Displacement flow in its original meaning is only used in special applications like clean rooms. Mixed flow is generally found in air-conditioned spaces, source flow which is frequently also called "displacement flow" is the usual type of flow in naturally ventilated spaces. This type had become more and more common in air-conditioned spaces in recent years.

The pattern of airflow influences the propagation of airborne pollutants, the thermalenvironment and general comfort conditions. In designing a good HVAC system, it isideal to determine the airflow distribution in the occupied zone to ensure good quality ofair and comfort condition are provided to the occupants. In most instances, it may not befeasible to conduct such study experimentally. This paper presents an investigation on thepredictions of air movement within a room and compared them with the physicalmeasurements.This study is carried out in a seminar room at a University.