Carbon dioxide produced by occupants can be used as a natural tracer gas for analysing air change rates in dwellings. However, a high level of concentration uniformity is necessary for tracer gas measurements. Therefore, mixing fans are usually used. The use of such fans in occupied homes is not convenient, thus the uniformity requirement may not be fulfilled. Experiments in climate chambers were carried out to simulate the distribution of CO2 under different controlled conditions, without additional mixing. Sufficient concentration uniformity was observed in all measured cases.

The segmental equivalent temperature determined by means of a thermal manikin is often correlated with the local thermal sensation of people and is used for indoor environment assessment. It is also used to assess performance of heated/cooled/ventilated car seats, etc. However, the body of the thermal manikins used at present is not as flexible as the human body and is divided into body segments with a surface area that differs from that of the human body in contact with a surface. The area of the segment in contact with a surface will depend on the shape and flexibility of the surface.

Carrying out tests on occupied buildings presents several challenges. Typical instrumentation that can be used in unoccupied test cells cannot be used in occupied spaces. We have videotaped the behavior of helium filled balloons to track the airflow patterns within the building. If the balloons closely follow the local average airflow behavior they will provide substantial insight. For neutrally buoyant balloons, the observed horizontal motions should provide an accurate picture of the corresponding air motions.

In this paper a new test room for thermofluidynamic measurements is presented. The tests have been realised in the Officine Volta (Italy) workrooms as result of a collaboration between researchers of the Department of Fisica Tecnica University of Rome La Sapienza and researchers of the Officine Volta society. The laboratory was thought exploiting the knowledge in the field of thermofluidynamic achieved by the department of Fisica Tecnica in the last few years.

Carbon dioxide exhaled by people can be used as a tracer gas for air change measurements in homes. Good mixing of tracer gas with room air is a necessary condition to obtain accurate results. However, the use of fans in dwellings to ensure mixing is inconvenient. The natural room distribution of metabolic CO2 was simulated in laboratory experiments and verified in a field study. The results of the field measurements presented in this paper support the findings of the laboratory study, i.e. that CO2 is well mixed into the room air even though fans were not used.

Tracer gas sorption in and permeation through building materials influence tracer gas ventilation measurements. The permeation of the commonly used tracer SF6 through three different building materials (gypsum board, wood particle board and MDF-board) with and without paint has been experimentally investigated. The results show that the tracer diffuse through untreated boards and that gypsum board has the largest permeability towards SF6. However, the diffusion rate of tracer is effectively reduced when the boards are coated with two layers of latex paint.

In this study, the houses located in the northern region of Japan had been investigated. The investigation included the measurement of the ventilation rate using four different methods, namely the constant concentration method, measurement of airflow at inlet/outlet and two kinds of PFT method. This paper shows the relationship between the measurement results of ventilation rate via these four measurement methods. It is found that the amount of outdoor air introduced is insufficient for many houses and some of the used ventilation systems are not properly operated.

Natural night ventilation is an energy efficient way to improve thermal summer comfort.Coupled thermal and ventilation simulation tools predict the performances. Nevertheless, the reliability of simulation results with regard to the assumptions in the input, is still unclear. Uncertainty analysis is chosen to determine the uncertainty on the predicted performances of natural night ventilation. Sensitivity analysis defines the most important input parameters causing this uncertainty. The results for a singlesided ventilation strategy in a single office are discussed.

In this paper a method to solve a design problem of hybrid ventilation system is proposedby building stack pressure around the ventilator using a flat bed, glass-shielded rectangular solarchannel. In support of this idea a CFD (Computational Fluid Dynamics) simulation based ontheoretical calculation is done. Here, natural convection and a k-e two-equation turbulence modelwere used together with the finite volume method.

The authors recently reported the detailed experimental results on that the discharge coefficient of the openings exposed to the wind driven airflow clearly changes depending upon the windangle and consequent conditions. A full-scale building model in a wind tunnel has been used for theexperiment. In this paper, the mechanism of the change is discussed more deeply, and the predictionmethods of the discharge coefficient are tested by the new experimental results for different conditions of opening size and location.