Zonal model for natural ventilation of light well in high-rise apartment building.

The light well located in the center of high-rise apartment building in Japan is called "Void". Gas water-heaters settled in Void discharge the exhaust gas into Void so that the enough opening area has to be designed at the bottom of Void to keep the IAQ in Void. In order to secure the IAQ in Void, a simple zonal model to calculate the ventilation rate induced by the wind force and the thermal buoyancy through openings at the bottom of Void with heat sources like water heaters is presented. And the accuracy of this calculation method is examined by wind tunnel test.

A new technique for measuring air change rates in a cross-ventilation model using the step down method of video image signals.

Air change rates in a cross-ventilation model were measured from the decay curves of video image signals obtained by the step down method assuming perfect mixing of tracer mists inside the spaces. Wind tunnel test results led to the following conclusions. 1) Ray extinction due to lighting scattering did not affect the measurement accuracy of the air change rates in the two-dimensional model. 2) Tracer mists in a diameter between 0.25 μ m and 2.0 μ m produced the same measurement accuracy.

Physical processes in ice rinks studied with small-scale modelling.

The study reported in this paper is concentrated on the estimation of the heat transfer from air to ice due to convection. Together with measurements of temperature and moisture profiles, air movements have been visualised in a small-scale model of a planned indoor ice rink. Some field tests concerning moisture content and temperature also have been realized in two different ice rinks. The study indicates that a low emissivity layer in the ceiling decreases the risk for ceiling condensation, decreases the heat radiation on the ice and decreases the driving force for air mixing.

Study on the estimate of the air conditioning control systems in large dome.

In the large space, for example in large-dome, the space is often divided into some zones without partition walls for air conditioning. In this case the following are problematic, The first problem is that it is difficult to control the temperature of the target zone considering the influence by the supply air temperature in the adjacent zone for air conditioning. The second problem is that it is difficult to set the temperature sensor for air conditioning control at the location in which the temperature means the average temperature in the target zone.

Application of wind tunnel experiment and CFD simulation on estimation of wind environment inside and outside a large-scale building complex with an atrium space.

For a large-scale building complex planned to be built in urban area, airflow around buildings and airflow inside a ventilated atrium of the building complex were estimated by CFO (Computational Fluid Dynamics) simulation, and wind and thermal environment were evaluated. The accuracy of CFO simulation was assessed by comparison with wind tunnel experiment. It was found that CFO tends to underestimate the air velocity near the ground surface compared with the results of wind tunnel experiment.