有機朗肯循環系統(Organic Rankine Cycle, ORC)，能夠有效的回收廢熱，並將原本無用且可能造成環境污染的低溫廢熱，轉為高價值的電力。其工作原理主要利用廢熱來加熱熱水，輸送至ORC系統之蒸發器來加熱冷媒，使冷媒產生高壓推力，推動渦輪發電機以產生附加價值電力；冷凝器則是利用冷水將發電過後的冷媒冷凝，以利下一次循環使用；冷凝器出口產生的溫水則輸送至冷卻水塔，將剩餘熱量排放至大氣中。
本論文乃依熱交換器設計中ε-NTU(effectiveness-Number of Transfer Unit)方法，於有機朗肯循環系統中的三種熱交換器：管式熱交換器(鰭管及裸管)、殼管式熱交換器、密閉式冷卻水塔，針對不同參數變化建立其熱液動性能之理論模式，並發展套用於個人電腦使用之交談式電腦輔助設計軟體。程式中提供各種流體包含水、空氣、熱媒油、Silicone Oil、R-245fa等冷媒，及廢熱氣成分 (包含CO2、CO、N2、O2、SO2、H2O) 輸入，方便使用者計算其所需物理性質，並將從事熱交換器熱液動能設計時必須使用的圖表和繁雜計算手續電腦化。透過軟體所提供友善的交談式操作介面，讓使用者能輕易且迅速地獲取可靠的計算結果以茲參考利用，來完成有機朗肯循環熱交換器的性能評估及尺寸設計工作。
本程式設計可執行下列二項功能：
(A)性能評估問題( Rating Problem)：使用者輸入一熱交換器的實際尺寸及冷側和熱側流量、進口溫度，則可求出兩側出口溫度及壓力降等結果。
(B)尺寸計算問題( Sizing Problem )：當告知熱交換器冷側和熱側流量和進口及出口溫度，即可計算出熱交換器有效性及相對應熱傳面積，根據使用者需求透過軟體輔助設計熱交換器尺寸，包含管數和外形幾何等尺寸大小等結果。

An Organic Rankine Cycle (ORC) could recover waste heat effectively. It could translate low-grade waste heat which may cause environmental pollution to high-worth electric energy. The waste heat is used to be a heat source to heat fluids such as water, dowtherm or silicone oil, and the heated fluids are delivered to evaporator. The refrigerant in evaporator would be heated from the phase subcooled to superheated, and then it produce high pressure driving turbine to generate electric energy. The refrigerant exited from turbine would be delivered to condenser and cooled by cooling water to the subcooled phase for the using of next cycle. However, the warm water is rejected by condenser, and delivered to cooling tower, which could reject remaining heat to the atmosphere.
This paper analyzed thermal-hydraulic performance of different types heat exchanger in ORC : tubular heat exchangers (fin tube and bare tube), shell and tube heat exchangers, closed-type cooling towers. Base on ε-NTU (effectiveness - Number of Transfer Unit) method, this paper also develop the computer aided-design softwares. The software provide several fluids and refrigerant such as water, air, dowtherm, silicone oil, R-245fa, and flue gas (which is composed of CO2, CO, N2, O2, SO2, and Steam) for user using. By software frendily and interactive interface, user could obtain reliable results and complete design work of the ORC heat exchanger easily and quickly.
The software applies to
(A) Rating Problem：Predict the performance when the dimensions of heat exchanger are given.
(B) Sizing Problem：Determine the necessary size when given the required performance.

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