These problems can be overcome by compensating for the pressure drop over the flow meter in such a way that the pressure on the duct side of the grille remains the same before and after the positioning of the flow meter. This is a very well known technique. However in the field of air conditioning, devices using this principle are rare. The compensation of the pressure drop is performed by a fan and regulator which blows just enoughair through the flow meter to meet the pressure compensation before the grille.
This paper describes the extension of the previously described UMIST technique for the determination of airflows between two interconnected cells to the case of three connected cells, and gives the results obtained for a series of validation experiments carried out under controlled conditions.
In Finland, there are three main topics in the field of air infiltration research: * simulation and measurement of air-leakage rates in building components and in buildings as a whole * airtightness and indoor air quality (thermal comfort) * thermal effects of air flow in building components. Goes on todiscuss aspects of air infiltration research in Finland.
IEA Annex 23 has been established in order to attempt to resolve these difficulties in relation to multizone air flow modelling. These models are used to evaluate the air flow between individual rooms or zones as well as the rate of inflow andoutflow of air from buildings. This approach is especially important for evaluating the adequacy of ventilation, predicting pollutant transport and evaluating airborne heat transfer between zones. Such models therefore have vital applications in both energy and air quality related analysis.
A set of reporting guidelines has been established. The guidelines take into account the need for data concerning airflow within buildings and air exchange between a building and its surroundings. They also deal with issues such as pollutant production and transport, thermal properties and measurements of buildings and comfort related issues. The comprehensive nature of these guidelines should enable a large amount of data to be accrued in a form suitable for computer modelling and validation work.
Turbulent flow fields of velocity and diffusion in several types of mechanically ventilated rooms are precisely analyzed both by model experiment and by numerical simulation based on the k-s two-equation turbulence model. The detailed analyses of contaminant diffusion by simulation make it possible to comprehend clearly the structures of velocity and diffusion fields in rooms. The flow fields in such rooms, as analyzed here, are mainly characterized by the inflow jet and the rising streams around it.
This paper describes the techniques used within the ESP system to represent and solve the heat and mass conservation equations relating to combined building and plant systems. In particular, it describes the equation-sets used to represent inter-zonal (building) and inter-component (plant) fluid flow and the method used for the integration of the non-linear heat and mass flow equations. By means of a case study, the application in a realdesign context is demonstrated.
Pressure models require a good knowledge of the pressure distribution around the building and a precise description of air paths. The hydrodynamic behavior of these connections is usually reduced to an empirical power law Q = K.dP(n) with n equal to 0.5 for a turbulent flow and 1.0 for a laminar one. We present three levels of approach to improve our knowledge of the flow behavior of building components. First, we propose a new light experimental tool to determine the on site flow behavior of building elements.
This paper discusses three methods for measuring interzonal air movements in two zone buildings: 1. initial injection of one tracer into a single room, 2. repeated injection of one tracer in two rooms, 3. initial injection of two tracers in two rooms. The description of these methods includes an outline of the theoretical background, the presentation of suitable injection strategies and algorithms for the evaluation of the concentration profiles.
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