English

The winter thermal environment and indoor air quality in classrooms has been reported to be very poor in Japan. In this study, an air-conditioned, mechanically ventilated classroom was surveyed. Air temperature, globe temperature and the concentration of CO2 were monitored before, during and after the three-hour occupancy by 35 adults. Airtightness and airflow rates of the ventilation system were also measured.

Natural ventilation has been appraised as the main strategy in environmental control of airborne infection in resource-limited healthcare facilities. While natural ventilation offers a low-cost alternative in diluting and removing contaminated air, its’ performance in actual settings is not fully understood. This paper reports a cross-sectional field study of six hospitals in Thailand with an emphasis on ventilation performance of naturally-ventilated hospital wards and AII rooms. The results showed that ventilation rates of 3-26 ACH could be achieved in hospital wards.

This paper describes the energy-saving effects of the proposed system with an active ventilation function and a heat pump for heat recovery. First, the temperature of the air supplied through the porous material versus the outdoor temperature was calculated using computational fluid dynamics to set the boundary conditions for the energy simulation. Then, the cooling/heating loads of a typical residential building in Japan were calculated and comparisons were made with and without the proposed system installed.

In order to insulate buildings more efficiently, many insulation methods have been proposed and successfully applied to the building envelope, including areas such as walls and windows. However, it is also important to insulate window frames efficiently because they usually contribute the greatest heat loss. The authors propose a new dynamic insulation system for window frames, with an active ventilation function and a heat pump for heat recovery.

The solar thermal desiccant cooling system was numerically investigated for application in the Asia-Pacific Region (East Asia and South East Asia). The system was modeled in transient system simulation (TRNSYS) program and applied in a hypothetical office building. The typical meteorological year (TMY) was used as the basis for the climatic conditions. The system was applied in the region’s sixteen major cities covering the temperate, sub-temperate/sub-tropical and tropical climates.

Residential buildings newly constructed in Japan are well insulated and airtight for energy conservation. However, the indoor environment of these houses can suffer from high humidity in the summer and low humidity in the winter. In order to mitigate this problem, hygrothermal materials are installed in some Japanese houses. The test method for small samples of hygrothermal material is prescribed in the Japanese Industrial Standards (JIS). However, the moisture buffering effect of the hygrothermal materials adopted in actual houses is unclear.

In Korea, in 2006, the building regulation was revised to apply 0.7 ACH (Air Change Rate) ventilation systems to improve indoor air quality in residential apartment housing. The purpose of this study is to evaluate energy requirement and indoor contaminant level characteristics for residential building applying with sensor-based DCV (Demand Control Ventilation) system.

Although theoretical studies show that energy use for ventilation purposes can be reduced by more than 50% with DCV compared to CAV, evaluation of real energy use demonstrates that this potential is seldom met. DCV-based ventilation systems must become more reliable to close the gap between theoretical and real energy-performance.

When it comes to natural ventilation performance for large space cooling during summer time or intermediate seasons, double skin facade(DSF) integrated with cross ventilation(CV) exhibits more energy efficiency than single-side ventilated DSF. In this case, ventilation performance is remarkably affected by climatic conditions. Therefore, it is important to analyze micro climatic conditions before applying this passive technique.

The effects of roof window on ventilation flow rates and reduction of cooling loads in densely populated areas were investigated by using building simulations. In May of the intermediate season, when utilizing roof window, the cumulative number of air exchanges increased by 9 % to 12 % compared to that when the windows at side walls remained open only during the daytime. When the building coverage ratio increased from 0 % to 20 %, the cumulative number of air exchanges decreased and the cumulative cooling loads increased.