Hans Stymne

An incongruent heat-of-fusion system—CaCl2·6H2O—Made congruent through modification of the chemical composition of the system

An Incongruent Heat-of-Fusion Storage System CaCl2.6H2O Made Congruent through Modifi-cation of the Chemical Composition of the System

Measuring ventilation rates in the Swedish housing stock

Abstract A passive tracer gas method is applied to measure ventilation rates in a nation-wide indoor climate study of a statistical sample of the Swedish housing stock. The method and experimental design are described, together with the results and some experiences gained from the project. The evaluation and error analysis techniques are discussed from an example. Special attention is paid to the accuracy of the results and the probable causes and size of errors. It is shown that the ventilation flow rates could be estimated to an acceptable degree of accuracy. Distributions of ventilation rates in single- and multi-family buildings are presented and discussed. It is shown that actual ventilation rates in dwelling are generally low compared to the requirements in Sweden since 1975, especially in single-family houses. The average ventilation rate per occupant is however very similar in multi- and single-family buildings.

Passive Tracer Gas Measurement of the Long Term Variation of Ventilation in Three Swedish Dwellings

Abstract The objective of this study is to investigate how measured ventilation rates in dwellings vary over the heating season in a Nordic climate. The aim is to draw conclusions about the possibility to transform a measurement result obtained during a relatively short period of time into one which would have been expected as an average over a whole season. If such normalisation of measurement data is not possible, dwellings may be misclassified as under-or over-ventilated, a matter which may dilute a possible relationship between health and air quality in epidemiological studies. Passive tracer gas measurements of ventilation were performed in a detached single-family house and in a flat (apartment) in Stockholm during four consecutive winter seasons. Measured averages of air change rate data are reported for 47 two-week periods for those two naturally ventilated dwellings. Another measurement using two different tracer gases was performed in an airtight, extract ventilated detached house over one year. The variation of ventilation is discussed in terms of variation in the ventilation driving forces induced by inside-outside temperature differences. The naturally ventilated house shows a slightly better correlation between air change rate and indoor-outside temperature difference than the town flat. It is concluded that the correlations are not good enough for predictive use for either dwelling. Therefore it does not seem possible to “normalise” ventilation measurement data. A slightly better possibility to predict the weather influence exists for the airtight, extract ventilated house. A possible reason for the lack of good correlation between air change rate and natural driving forces is a highly variable influence from occupant behaviour.