The computer programs published so far have enabled the calculation of airflows at constant temperatures or of air temperatures at constant airflows. The first version of a new microcomputer program has now been developed in which the airflows and temperatures are calculated simultaneously. The time dependency of temperatures, airflows and contaminant concentrations is considered in the calculation method. The source strength of contaminants, outdoor air temperature, wind velocity and direction, convection and radiation loads can all be freely scheduled.

Simulation models basing on 2-dimensional finite-difference approach were developed for the steady-state and dynamic analyses of the thermal coupling of leakage airflows and building components. The considered types of leakage flows were crack flow and filtration through porous materials.

Combined ventilation and heating systems in floors demand extensive investigations about the heat transfer before they could be installed in residential buildings. For basic investigation about the heat transfer two experimental plants with different duct geometries are build in a laboratory of the University of Essen. Especially the measurements of temperature on different places of the plants are taken to determine the heat transfer at the two floors.

Sandberg and Skaret differentiate between the terms air change efficiency and ventilation effectiveness. Air change efficiency is a measure of how effectively the air present in a room is replaced by fresh air from the ventilation system whereas ventilation effectiveness is a measure of how quickly an air-borne contaminant is removed from the room. The AIVC guide covers ventilation effectiveness and related concepts. It shows the origins of the concepts used, provides proofs of essential formulae, and suggests standard symbols and definitions.

This paper presents a new approach to determine the interzonal airflows of a multizone system using tracer gas measurements. In contrast to methods proposed earlier, the presented method does not use the mass balance as basis for the least squares problem but identifies the interzonal airflows as coefficients of the evolution equations for the concentrations. Therefore estimating the derivatives with respect to the time from measured data is avoided. Furthermore the concentration can be calculated at arbitrary points in time.

This paper extends the integral mass balance approach to the remaining constant concentration technique. An integral formulation of the constant concentration problem is presented that accounts for the possibility of variation of tracer concentration. This approach leads, in principle, to data reduction strategies that may be expected to improve the accuracy of the constant concentration technique and that may be used to isolate those portions of a given constant concentration data set that are likely to be most reliable.

This paper reports the design, development, calibration and testing of a fast-response, multi-channel tracer gas concentration measuring instrument. The instrument uses aninnovative application of Infrared Absorption techniques to measure Sulphur Hexafluoride (SF6) concentrations. This approach allows the overall cost of a multi-channel continuous-recording unit to be reduced without sacrificing overall performance. A calibration over the range of 5.0 to 50.0 ppm V SF6 is shown. The current measurement resolution is 0.06 ppm V, and the accuracy is + or - 5.0%.

Tracergases provide a way to determine airflows in different situations. In some cases it is the only way to get quantitative information. This paper presents two cases in which tracergases are used for measuring the internal leakage in heat recovery units. Internal leakage in heat recovery ventilators (HRV's) for domestic use may cause some problems: - the real quantity of fresh air entering the building is unknown - electrical power for the fans is used inefficiently - smelling air a.g.

A new passive tracer gas method for ventilation measurements is described. The method utilizes passive tracer gas release from aliquid perfluorocarbon compound contained in a glass vial, equipped with a teflon membrane. Air sampling is also done passively by diffusion through a glass tube containing activated carbon. Quantitative analysis of trapped tracer compound is performed by solvent extraction and gas chromatographic separation using a liquid injection technique. Separation is done with a two-column system and quantitative analysis with an electron capture detector.

Knowledge of air movement within a building is often a condition for solving problems with the spread of pollution. The internal airflow paterns are mostly very complex and a survey of the airflow normally demands that measurements are carried out. Measuring equipment for defining air movement within buildings almost always uses the tracer gas technique. We have used two tracer gases and have kept a constant concentration of these in the polluted and the clean zones respectively. Thus enabling us to get a time history of the airflow between the two zanes.