講廳在不同形式的自然與機械換氣之二氧化碳濃度

Carbon Dioxide Concentration of Lecture Classrooms in Different Forms of Natural and Mechanical Ventilation

室內空氣換氣品質逐漸受到重視，對於室內空氣品質也有不少相關規範，尤其人數眾多的講廳容易造成高濃度二氧化碳，為了提高換氣效率，通常會設置換氣設備例如全熱交換器，但學校每年編列的空調換氣設備更新維護預算有限，多數老舊教室設備更汰換速率慢，會以既有設備持續使用，較無法統一保證講廳室內換氣品質。因此，本研究在既有空調換氣設備條件下，利用四類不同講廳建築開口來探討自然換氣效率可行性，並作為設備更新維護前的暫時替代方針。本研究於四類不同講廳進行自然與機械通風換氣效率量測，參考國際講廳換氣標準需換氣量與換氣次數，依序為3887.5m3/2.5次（新建密閉）、3272.8m3/3次（舊有密閉）、1504m3/2.5次（單面開窗）與4136.9m3/2.6次（多面開窗）。並依照講廳不同的開口形式與既有換氣設備搭配組合，提出不改變設備系統，讓使用管理者容易使用與管理，並有效提升講廳換氣效率的替代方案。實驗證實，舊有密閉講廳的換氣效率從0.47次提升到2.09次，而新建密閉講堂更是可能由0.54次提升到最大4.61次，明顯有效提升換氣效率與無設備成本支出。

Indoor air ventilation quality has been paid more and more attention. There are many relevant specifications for indoor air quality, especially in lecture classrooms with a large number of people, which are prone to high concentration of carbon dioxide. In order to improve ventilation efficiency, ventilation facilities, such as energy recovery ventilation, is usually set up. However, the annual update and maintenance budget of air conditioning ventilation facilities compiled by the school is limited, and the replacement rate of most old classroom facilities is slower, The existing facilities will be used continuously, which is less able to uniformly ensure the indoor ventilation quality of the lecture classrooms. Therefore, under the condition of existing air conditioning and ventilation facilities, this study uses four different lecture classrooms building openings to explore the feasibility of natural ventilation efficiency, and takes it as a temporary alternative policy before facilities renewal and maintenance. This study measured the ventilation efficiency of natural and mechanical ventilation in four different lecture classrooms. Referring to the international lecture classrooms ventilation standard, the required air exchange volume and ventilation times are 3887.5m3/2.5times (newly closed), 3272.8m3/3times (old closed), 1504m3/2.5 times (single side window) and 4136.9m3/2.6 times (multi side window). According to the different opening forms of the lecture classrooms and the matching and combination of the existing ventilation facilities, this paper puts forward an alternative scheme that does not change the facilities system, makes it easy for users and managers to use and manage, and effectively improves the ventilation efficiency of the lecture classrooms. Experiments show that the ventilation efficiency of the old closed lecture classrooms can be increased from 0.47 times to 2.09 times, while the new closed lecture classrooms can be increased from 0.54 times to the maximum of 4.61 times, which can effectively improve the ventilation efficiency and no facilities cost.