English

A test room with a Displacement Ventilation System was built. Temperature control was provided with a DDC (Direct Digital Control) System, controlling the air volume and the air inlet temperature. Air velocity and temperature profiles were measured at different locations in the room for various internal loads. The aim of the control was not only to provide a constant temperature but also comfortable conditions. the temperature gradient, the air velocity and the radiant heat exchange were taken into consideration for the comfort condition in the space.

The work in this paper contributes to the work in the IEA - Annex 20 "Air Flow Patterns within Buildings" and presents a series of full-scale measurements of the concentration distribution in a room with isothermal mixing ventilation. Vertical profiles of the concentration in the middle of the room have been measured under different conditions. With the contamination source in the middle of the room the vertical profiles were changed radically with an increase of the air change rate from n= 1.5h^-1 to n=6h^-1 due to a change in the flow structure in the room.

Air infiltration and ventilation has a profound influence on both the internal environment and on the energy needs of buildings. In most electrically heated high-rise residential buildings, in cold climates, during the peak winter conditions (below -18 deg C ambient temperature and above 15 km/hour wind velocity), the air infitration component contributes to heating load by 10 to 28 w/m2 - roughly 25 to 35% of peak heating demand. Any reduction in such uncontrolled air infiltration, without sacrificing indoor air quality, will have potential to reduce the peak heating demand.

This speech comprises a summary of two publications from the Swedish Council for Building Research (BFR); the knowledge survey "Buildings and Health" (BFR T4:90) and "Indoor climate and energy husbandry" (BFR G5:90). One central conclusion presented in both these publications is that the hygienic and climatic requirements are frequently neglected and that they must reassume a central position in the building and building management process.

This article discusses the application of tracer gas methods to industrial hygiene investigations. It introduces the basic concepts necessary to understand the application of tracer gas methods to particular airflow and contaminant movement measurements. It provides an overview of existing methods which can be used to obtain quantitative data on a variety of airflow and contaminant movement related questions which often are of interest to the industrial hygienist.

Tracer gas tests were conducted on a five-storey apartment building to determine the air and contaminant flow patterns within the building. The test method involves the injection of a small amount of tracer gas, SF6, into a selected location to create a single source and monitoring the tracer gas concentrations at locations throughout the building. Based on the rates at which the tracer gas concentrations change at various locations, the air and contaminant flow patterns within the building can be determined. Several such tests were conducted.

The knowledge of IEA-Annex 14 'Condensation and Energy' has been applied to develop a new strategy for humidity control in dwellings. The presented control element assures safe prevention from mould growth at a minimum energy consumption. The advanced humidity control device consists of a surface temperature and an indoor air temperature sensor, from which readings a microcontroller evaluates the appropriate RH setpoint. A humidity sensor then reads the actual RH in the room air and compares it with the momentary setpoint.

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%.

A new handbook, describing in details the measurement techniques which could be used to better understand the infiltration and ventilation in buildings is presented. This handbook results from the cooperation between Annex 20 and Annex 5 of the IEA ECB program. It presents the techniques for detecting and measuring as well the air leakages as the air flows in buildings and inventilation systems. Methods related to ventilation efficiency and effectiveness, like the measurement of the age of air, are also described.

A new algorithm for the continuous measurement of variable air change rates with tracer gases will be presented. It differs from the constant concentration method by allowing the concentration level to vary according to the air change rate. Also the mixing process of tracer gas within the room under investigation is considered and limited measurement ranges and injection rates of the tracer gas equipment can be accounted for. The new algorithm has a number of advantages, such as quick response to variations in the air change rate and reduced tracer gas consumption.