太陽能集熱器是一種結構簡單、容易維護的加熱器；其主要可用於社區及家庭用水之加熱、室溫調節、蒸餾系統及乾燥等用途；對太陽能集熱器效率的影響因素甚多，尤以集熱器之流體流動組數、流體總流量及迴流比值所造成的影響最為顯著。本文建立對矩形通道平板型太陽能集熱器之數學模型與實驗裝置來，探討迴流效應、集熱器之流體流動組數、矩形通道之縱橫比、流體總質量流率、進口溫度、太陽光入射強度等參數對集熱效率的影響，並討論其集熱效率提升率與水力消耗增加量，而得到經濟考量下之最佳設計與操作參數，並且進一步地將所得到的結果與傳統圓管單行程之太陽能集熱器相比較。研究結果顯示，具迴流型比傳統單行程之太陽能集熱器有較高之集熱效率，且集熱器之集熱效率隨著流體總質量流率、太陽光入射強度及矩形通道之縱橫比增加而提升。 The study presents theoretical and experimental results of the device performance on flat-plate solar water heaters with rectangular flow ducts under recycle operation. Comparing with the results of conventional type collector, the theoretical and experimental results show that the collector efficiencies can be effectively enhanced by using the present device with recycle operation. The theoretical and experimental results of flat-plate solar water heaters with rectangular flow ducts have been carried out with the recycle ratio, number of pair ducts, aspect ratio of flow ducts, mass flow rate, inlet fluid temperature and incident solar radiation as the operating and design parameters. The collector efficiencies for flat-plate solar water heaters with external recycle increase with increasing recycle ratio, mass flow rate and incident solar.
