空調箱（AHU）用於恆溫恆溼場所之節能研究

THE ENERGY-SAVING STUDY OF AIR HANDLING UNIT USED IN THE PLANT OF CONSTANT TEMPERATURE AND HUMIDITY

本研究針對傳統空調箱好能之缺失作改造，在回風管路增設一旁通風門，將相對冷卻盤管處理後之高溫高濕現場回風導入風扇吸入端與經降溫除溼之空氣混合提高其溫濕度，進而可減少再熱設備之加熱能耗，再搭配變頻器作變風量控制，以符合現場環境負載之變動，達最佳節能效果。於恆溫恆濕控制場所之空調箱增設外旁通風管，並利用實驗及理論分析等方式，來求得其運轉狀態、可靠度及旁通風門改裝前後之能源耗量比較，以提供傳統式空調箱在恆溫恆濕控制場所之節能方式參考。利用顯熱平衡計算公式與熱平衡空調顯熱總負荷計算式，可得旁通風量與節能量成正比，即旁通風量越大，節能效果越佳。又由空調顯熱負荷計算公式可得知，當負荷變化下可進行風量的改變，以對應適當之熱荷負荷需求，可有效節省風扇泵輸出功率。此外，實驗結果發現：原本回風需全風量經冷卻盤管降溫除溼，經設置旁通風門後可減少加熱器能耗50.4%，變頻器變風量後節省風車能耗89.6%，冰水能耗減少1.2%，平均節省能耗合計40.2%，由實際運轉結果知空調箱於恆溫恆濕場所，裝設旁通風門確為可行之節能措施。 An improvement of the AHU is presented in this study. To decrease the heating energy consumption, a bypass damper is installed in the return-air-duct. To adapt the variation of the working load, one more frequency converter is used to control the amount of air needed. This study investigates the energy-saving of the AHU with bypass duct in an air-conditioning system both theoretically and experimentally. The status of operation, reliability and the comparison of power consumption before and after the installation of bypass damper in the duct are obtained for the design reference of constant temperature and humidity plants. From the energy balance of sensible heat in air-conditioning, it is known that the quantity of bypass air is proportional to the amount of energy-saving, i.e. the efficiency of energy-saving increases with bypass air. Moreover, the cooling air can be controlled in accordance with the load capacity and subsequently the power output of the fan can be effectively reduced. Experimental results show that the power consumption of the heater decreases 50.4%, the power of fan with frequency converter reduces 89.6%, however, a 1.2% power of refrigerating machine is reduced. Overall, the AHU with bypass duct and converter can save 40.2% power consumption in the air-conditioning system. Therefore, from the results of this study, the proposed design is feasible in real applications.