台灣地區人口稠密，天然資源貧乏，重要的原料多仰賴進口，而近十年來人口增長
迅速，加上工商業的蓬勃發展，造成民生用電的嚴重不足，使得政府不得不在夏季尖峰
時段採取限電措施。此外，絕大多數的電廠其效率不夠高，也使得發電成本提高，浪費
可用能源。有鑑於此，本文將以程氏汽電共生循環系統之熱力分析，作為未來電廠發展
之另一選擇。
本文係以熱力學基本定律為主，熱力性質方程式為輔，來探討分量注入式、全量注
入式之程氏循環的各種系統參數對整個系統效能之影響，並與其他熱力循環相比較。
首先，本文針對「分量注入式之程氏循環」進行分析。將此循環中之幫浦的水量固
定，而就不同的注入率下，計算系統的發電效率、系統淨功、燃料提供之熱。對於系統
中部份元件（壓縮機及燃氣渦輪機）之進出口狀態以重複疊代的方式求得。藉由觀察使
用因數、熱電比及發電效率三者隨注入率之變化，探討為何程氏循環在全量注入時之第
一定律效率降低時，吾人仍傾向將蒸汽完全注入。
其次，針對「全量注入式之程氏循環」進行參數分析。由於程氏循環系統龐大複雜
，影響系統效能之參數不勝枚舉，然較為重要之參數諸如汽注入量、壓縮比、氣渦輪機
進氣溫度及外界環境溫度等在本文中均有探討分析，並對上述參數改變系統效能之原因
作詳細之剖析。此外，於應用熱力性質函數時，由於缺乏低壓區部份之性質函數，故以
全壓取代分壓計算各成份氣體之熱力性質，因此在本文中對此作法與實際結果之差異性
亦有詳細之結果說明。
再者藉由與傳統氣輪機系統之效率等之比較可了解程氏循環之優點，而就不同觀點
觀察程氏循環與一般之汽電共生系統可發現，其彈性運轉範圍、低NOx排放量、高效率
及低初置成本是其他系統所無法同時兼備的。
綜合以上分析討論可知，不論是分量、全量注入式之程氏循環，就經濟上、效率上
、環保上均有絕佳的效能，可望為電力短缺的台灣帶來契機。

The population density and the living standard in Taiwan are rising steadily. In addition, most of the energy resources are heavily dependent on the import. The cost of electric power is continuously going up, and the reserve capacity of electric power is gradually drying out during the peak time. Therefore, it is very important for this country to gencrate more electric energy in a better way.
　A very efficient cogeneration system called Cheng cycle power system which should be perfectly fit to our electric generation need is analyzed in the present study.
　By the use of the basic laws of thermodynamics and the equations of thermodynamic properties, the effects of each parameter are investigated under partial and full steam injection conditions in Cheng cycle power system. The results are also compared to that of other systems.
　At first, the pumping mass flow rate is set to be a constant and observe the changes of the power generation efficiency, net work output and the heat rate required by the combustor under different steam injections. We can also find out the effects of various steam injection ratio on utilization factor, power generation efficiency and heat-to-power ratio and discern the reason why we would like to inject steam as much as possible even at a low overall system efficiency.
　Then, by observing overall system in full injection condition, we discover many important parameters such as the mass flow rate of injection, the compression ratio, the turbine inlet temperature and the ambient temperature will all effect the performance of overall system. Along the analysis we also demonstrate that there is only a small discrepancy if the total pressure instead of partial pressure of each constituent gas is used to obtain the thermodynamic properties in system calculations.
　Finally, the performance of a traditional gas turbine system pluses a boiler is compared with that of a Cheng cycle cogeneration system. We found that Cheng cycle system has many benefits such as flexible operation range, high power generation efficiency, low capital cost, less exhaustion of NOx, from which we can clearly evaluate the overall benefit of the Cheng cycle cogeneration system.