住宅中的厨房和卫生间,一般设计在卧室或客厅的下风向(北向),由于四季风向变化,不可避免产生“逆风”(北风),倒灌室内,使厨房卫生间产生的油烟、蒸气、湿热、二氧化碳等不良气体散发,污染卧室和客厅(图1),影响人体健康和室内正常活动。为此,很多住户购置电动排风扇,排除这些有害气体。若作为建房设备投资,就相当于每 The kitchen and bathroom in a dwelling are generally designed in the downwind (north direction) of a bedroom or living room. Due to the change of wind direction in the four seasons, it is inevitable to produce “wind” (northern wind), which will invert the interior and make the kitchen toilet produce soot, steam, hot and humid, Carbon dioxide and other harmful gases are emitted, contaminating the bedroom and the living room (Figure 1), affecting human health and normal indoor activities. For this reason, many households purchase electric exhaust fans to eliminate these harmful gases. If you invest in building equipment, it is equivalent to