The bristle of a rotating cleaning brush for air ducts was modelled using large deformaion elastic theory. The point collocation method with a trial solution consisting of undertermined parameters was employed to discretize the resulting non-linear problem. The main interest was in determining the value of the bristle tip contact normal force N, the bristle tip contact angle B and the torque T needed to rotate a brush. The results obtained using the simple model were compared with the results obtained from a laboratory test.

This thesis is based on studies undertaken during the period 1998-2003 at the HVAC laboratory of Helsinki University of Technology.The thesis focuses on dust accumulation in, and removal from, recently installed supply air ducts and on the bristle behaviour of rotating duct cleaning brushes. The results of dust accumulation, measured using three different methods, were compared and the amount of dust in newly installed air ducts was evaluated. The vacuum tests was found to be an efficient method of collecting dust samples on the duct surface.

The purpose of the present study was to evaluate the possibility to reproduce heat and air flowcharacteristics in a machine room where high heat generating systems and devices are installed. For this purpose, in an experiment room was air-conditioned by double floor air supply on the assumption that the machine room, data were selected such as air flow rate of the systems and various boundary conditions were elected. Further, double floor supply air flow rate distribution, and heat and air flow distribution in the room were measured.

The proposed local dynamic similarity model can select an adequate discharge coefficient to match the approaching flow angle. This is an improvement over the conventional orifice flow model where the discharge coefficient is set to a fixed value. The accuracy of predicting ventilation flow rates for an isolated cross-ventilation model is greatly improved when the discharge coefficients actually decrease with change of wind direction.

The effect of draughts on the steady thermal stratification established by a localised heat sourceat floor level in a naturally ventilated enclosure with upper and lower openings is considered. Ourexperimental observations in water using models indicate that four different steady flow patterns arepossible depending on the relative areas of the upper and lower openings.

We performed numerical simulation of the inflow characteristics at an opening by using LES,the standard k- emodel, and the improved k- emodel that was applied Durbins limitation (hereafter, it is described as Durbins k- emodel in this paper). As a result of this simulation, Durbins k- emodelreproduced the experiment result fairly well as in case of LES. Accordingly, by using Durbins k- emodel, the analysis was carried out on the air flow characteristics at some openings. As a result, the static pressure increase was induced by the collision of the air flow with the leeward opening frame.

Pressure loss mechanism at the inflow opening of Cross-Ventilation is studied by detailed analysis of LES results. Manipulation of energy transfer equation through inflow openings suggests that reduction of discharge coefficient should be originated from dynamic pressure in tangential direction and should be observed as increased static pressure at the opening.

The sick house syndrome has become a serious problem in Japan recently. It is important tospecify and quantify the source of chemical pollution. In this study, passive samplers for concentration of chemical substances in the air, ADSEC for emission rate of chemical substances from building materials and PFT method for ventilation rate in a room were developed. These passive methods enable investigation of many houses at a time. Indoor air quality of a newly built house was measured by these passive methods in summer and winter.

This study describes an experiment on a Task Unit and reports the results. The Task Unit coolsthe upper half of the body by isothermal air flow and warms the lower half of the body by a radiant panel. Tests were designed to compare heat removal by moving air after identifying the metabolic rate and how the thermal sensation and comfort sensation improve during the summer season. As a result, when the room temperature rises, the activity ratio of the Task Unit rises, too.

This research proposes a method for task area wide-cover personal air conditioning thatprevents a human body in the task area from being exposed to a largely irregular thermal environment. A Particle Image Velocimeter (PIV) was used in the research to measure air flow fields for conventional spot cooling and wide-cover personal air-conditioning(PAC) around the human body. The wide-cover type PAC formed a calm air flow field of less than 0.18m/s around the human body, while the spot cooling type PAC formed an air current of 0.3-0.6m/s around the area of the neck.