tracer gas method

Indoor air quality is the chemical, physical and biological properties that indoor air must have to not cause any negative impact on occupants’ health and provide comfort: feel fresh, pleasant and stimulating. 

There are two types of air conditioning systems, convective and radiant air conditioning system. Radiant air conditioning systems have attracted many people’s interest due to the high capabilities of energy saving and maintaining a comfortable indoor environment at the same time. However, it is difficult to install this system and maintain system performance. There is also a problem about the drought from convective air conditioning system.

Amid the contaminant issues, air pollution has awakened more interest due to its potential health risk and its direct effect on human productivity. The overall indoor environment quality depends on the contribution of both the indoor and the outdoor air quality. The outdoor air pollutants penetrate indoor environments through mechanical and natural ventilation as well as by infiltrations through cracks and leaks in building’s envelope. The interaction between the indoor and outdoor air may be studied by the air exchange rate.

Recently most houses in northern Japan are highly insulated and air-tight, which can lead to seriousproblems such as indoor air pollution. It is important to evaluate the performance of an air-tight housefrom the viewpoint of ventilation. However, in general, houses consist of multiple rooms and each roomhas airflows in different directions which mix with each other. Therefore it is not easy to measure realventilation rates.The purpose of this paper is to evaluate a simplified method for measuring airflow rates in houseswhich have a basement with outer insulation.

The keeping of animals in livestock buildings requires the ventilation of these buildings. On the one hand good climatic conditions for the animals in the livestock building have to be provided, on the other hand the emissions have to be kept at a low level. The airflow through the livestock building plays an important role for both opposing requirements. The targeted control of the climate in the livestock building and for the minimization of emissions calls for knowledge about airflow and emission streams.

The aim was to develop a simple dynamic model for predicting air exchange caused by short time single-sided ventilation and necessary window opening time in classrooms. Tracer gas measurements have been made in a full-scale room. The comparison indicates that the model can be used when rough estimates of air exchange are of interest.