Windcatcher louvers are designed to capture air flowing outside a building in order to increase its natural ventilation. There are no studies that have designed the shape of the louver to increase the natural ventilation efficiency of the building. This study aimed to conduct a computational fluid dynamics simulation and mock-up test of a Clark Y airfoil-type windcatcher louver designed to increase the natural ventilation in a building. The following test results were obtained. The optimal angle of attack of the airfoil was calculated via a numerical analysis, which demonstrated that the wind speed was at its highest when the angle of attack was 8°; further, flow separation occurred at angles exceeding 8°, at which point the wind speed began to decrease. The results of the mock-up test demonstrated that the time required to reduce the concentration of fine particles in the indoor air was 120 s shorter when the windcatcher was installed than when it was not, which indicating that the time to reduce particles represents a 37.5%reduction. These results can be seen as reducing the energy consumption of ventilation in the building because the natural ventilation efficiency is increased.

In South Korea, the gradual increase in particulate matter generation has received significant attention from central and local governments. Exhaust gas, which contains nitrogen oxides (NO_x), is one of the main sources of particulate matter. In this study, the reduction of NO_x using a coating material mixed with a titanium dioxide (TiO₂) photocatalyst was demonstrated. The NO_x reduction performance of the TiO₂ photocatalyst-infused coating was evaluated by applying the ISO 22197-1: 2007 standard. Subsequently, the performance was evaluated by changing the NO gas concentration and ultraviolet (UV)-A irradiance under standard experimental conditions. It was determined that NO_x reduction can be achieved even if the NO gas concentration and UV-A irradiance are lower than those under the standard conditions when the TiO₂ photocatalyst-infused coating was used. This study revealed that NO_x reduction can be realized through TiO₂ photocatalyst-infused coating in winter or cloudy days with a low solar altitude. It was also confirmed that compared with the UV-A irradiance, the NO gas concentration has a greater effect on the NO_x reduction performance of the TiO₂ photocatalyst-infused coating. These findings can be used to evaluate a variety of construction materials with TiO₂ photocatalysts in the future.

High-efficiency particulate air (HEPA) and charcoal filters have been applied to ventilation systems to save energy and reduce pollutants. However, such filters only work for specific types of pollutants, and their performance is not always sustainable. This study compares the pollutant reduction performance of TiO₂ photocatalytic filters with HEPA and charcoal filters in mock-up experiments with toluene as the pollutant, changing air volume, and varying ventilation frequencies. The results show that the HEPA filter was ineffective at reducing toluene, and the charcoal filter was found to have the fastest reduction rate until 180min after the start of the experiment. However, after 180min when the charcoal filter was saturated, its pollutant reduction performance rapidly declined, resulting in low persistence. Conversely, the TiO₂ photocatalytic filter had a lower reduction rate than that of the charcoal filter but had a continuous pollutant reduction performance during 720min. Comparing the pollutant reduction effect of the TiO₂ photocatalyst filter and the charcoal filter with a reduced amount based on the experimental time, the TiO₂ photocatalyst filter has a maximum pollutant reduction effect of about seven times and at least about two times. This study confirms that HEPA and charcoal filters reduce gas pollutants, and it was found that combining TiO₂ photocatalysts with ventilation devices can improve indoor air quality in apartment buildings.

In this study, a performance comparison experiment with a vortex exhaust installed at the end of a ventilation device to enhance the effect induced by reducing indoor pollutants was conducted. The experiment was carried out by constructing a mock-up room with a limited indoor environment, and performances were compared based on the following two tests. First, to confirm the effect of pollutant reduction, the wind speed was measured based on the distance from each exhaust system to verify the depth and speed at which wind can flow. Pollutants were induced to the vortex exhaust, general exhaust gasses were generated, and their performances were compared. Second, Arizona dust was used to confirm the performance with regard to the removal of pollutants which existed in particulate form (PM 10), and for CO₂ gas, a representative gaseous pollutant was used as a reference. Based on the results, it was confirmed that installing a vortex exhaust system can allow for the generation of wind speeds that allow propagation at greater depths (>110 mm) compared to cases in which general exhaust is used; accordingly, exhaust performance can be achieved at increased depths. In addition, the experiment confirmed that vortex exhaust can improve the efficiency of simultaneous removal of PM 10 and CO₂ compared with general exhaust. Further, it was shown that installing a vortex exhaust system can remove PM 10 and CO₂ farther from the exhaust port in a shorter period than a general exhaust port. In addition, it was inferred that vortex exhaust can be utilized to prevent indoor pollutants and diseases in combination with the latest technology.