目的：一般的鍋爐均以燃燒來產生之蒸氣作爲製造、消毒或動能之用，然其耗油量卻相當驚人。若能對鍋爐排放的廢熱氣加以回收再利用，不但可省油節能，節省成本，更可減少二氣化碳排放量，一舉數得是值得推廣的構想。本研究目的在於瞭解於小型鍋爐煙囪加裝預熱桶，回收煙囪排放之廢熱氣所產生之節能減碳之效益。 方法：本研究以一般醫院用之小型鍋爐爲例，在鍋爐煙囪處加裝預熱桶回收煙囪所排放之廢熱，將熱預熱桶中之冷水加熱爲熱水，並將加熱後之熱水再利用，以達到節能效果。爲探討此改良後鍋爐系統之節能節水效率，對預熱桶之溫度、用水量及燃油消耗量進行觀測，並對預熱桶中不同水溫時之燃油消耗與用水量進行比較分析。 結果：經分析試驗結果發現，新系統不但可節水及節能，更可減少二氧化碳排放。平均每日可節省用水45公升，節水效率達0.9%；平均每日可節省柴油使用量41.7公升，省油效率8.486%。每日可減少二氧化碳排放量達115.518公斤，其減碳排放量已達「京都議定書」規定之減碳排放標準。 結論：鍋爐新系統不但可節水及節能，更可減少二氣化碳的排放。該設備投資費用僅半年即可回收，很值得投資與推廣。

Objectives: The conventional boiler is used to produce vapour kinetic energy for use in manufacturing and sterilization, but it consumes a lot of oil. Production cost could be saved in an era of high oil price by economizing on fuel. Retrieving and recycling waste steam from the boiler could not only save oil used in production, but also reduce carbon dioxide emission. To achieve this goal, a new boiler system of heat recovery was proposed and its energy efficiency and reduction in carbon emission were investigated. Methods: A preheat barrel was installed around the boiler stack to retrieve waste heat from the stack discharge. The waste heat was used to heat cold water in the preheat barrel, and then the hot water was utilized. Results: The new boiler system saved every day an average of 45 liters of water and 41.7 liters of diesel fuel. The carbon emission reduction was as much as 115.518 kilograms every day, which meets the Kyoto Protocol standard. Conclusions: The new boiler system not only saves water and energy but also reduces carbon dioxide emission. The cost of this new system can be recovered in six months, which suggests that widespread deployment is feasible and beneficial.