本研究目的在於探討家用自然循環太陽能熱水系統對於節能減碳的效果探討與評估。探討輔助熱源的不同是否節省燃料能或者耗損燃料能，減少碳排放量或者增加碳排放量。
本研究以電腦模擬軟體TRNSYS計算出太陽能年負荷比與輔助熱源所需能量。利參考臺電發電的各比例與效率來計算電輔助太陽能熱水系統為增加碳排放或者減少碳排放量及節省燃料能源或者耗損燃料能量。
本研究比較四種熱水系統之能量消耗與碳排放：
1.全天然氣熱水器
2.全電熱水器
3.電輔助熱源太陽能熱水器
4.天然氣輔助熱源太陽能熱水器
結果顯示，電輔助太陽能熱水器不一定節能減碳，在太陽能較不充足的地區，或是負荷需求較大時，電輔助太陽能熱水器比天然氣熱水器還耗能而且增加碳排放，因此太陽能的功效付之厥如，只有天然氣輔助太陽能熱水器能夠節能減碳。

The purpose of this study is to evaluate the energy saving and the carbon reduction for the domestic natural circulation solar hot water system operated in Taiwan. The computer simulation software TRNSYS is employed to calculate the annual load requirement, annual auxiliary energy consumption and the solar fraction (the fraction of load supplied by solar) for six representative sities of Taiwan. With the data of the fossil fuel fraction of the total power generation of Taiwan Power Company, the actual energy saving and CO2 reduction of the solar hot water systems are estimated.
　The results show that using solar hot water system with electric auxiliary heating to replace gas hot water system may consume more fuel energy than load demand and increase CO2 emission.
It is suggested that electric auxiliary heating should be replaced by gas auxiliary heating such that the solar hot water system can really become a green energy product.

論文審定書 i
致謝 ii
摘要 iii
Abstract iv
目錄 v
圖目錄 vii
表目錄 x
符號說明 xii
希臘符號 xiv
第一章 緒論 1
1-1 前言 1
1-2 文獻回顧 1
1-3 研究動機與目的 2
第二章 基礎理論 5
2-1 家用自然循環系統介紹 5
2-2 家用自然循環系統之組成 5
2-3 TMY2氣象資料 9
第三章 研究方法 14
3-1 家用自然循環系統模擬概述 14
3-2 太陽能負荷比(Solar fraction) 14
3-3 CO2排放之計算 15
3-4 節、耗燃料能與總消耗熱能之計算 16
第四章 結果與討論 20
4-1 不同取負荷時間之比較 20
4-2 CO2排放量 21
4-3 節、耗燃料熱能與總消耗熱能 23
4-4 不同負荷量對節能減碳的影響 27
第五章 結論與未來展望 92
參考文獻 94

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