실내 공기질 및 에너지 절약을 위한 고속버스의 자연형 환기시스템

In the wake of measuring the indoor air environment in express bus in operation, unbalanced indoor temperature and air quality appeared to be inferior. The relative humidity measured 20% was far below than 40~60% required for comfortable indoor environment, causing the passengers to suffer sore throat and stuffy nose. CO₂ measured was 1,500 ppm on average when 15 passengers were on board and 2053 ppm for 29 passengers, which far exceeded 1000 ppm, the limit for public facilities. CO₂ density was getting increased during operation till the bus stops at service area for 15 to 20 minutes, which was however again deteriorated when bus started running. Thus appropriate ventilation system is expected to help maintain the comfortable indoor environment. In an attempt to investigate the vent performance of the bus in operation, CFD simulation was conducted at the speed 60, 80 and 100 km/h and as a result, only a partial ventilation, instead of uniform ventilation, was achieved. And the effect of reducing the CO₂ by vent system using existing vent hole or ceiling structure was found to be more effective than existing vent device.