噴霧裝置應用於複合式熱交換器之理論分析與研究

Abstract

近年來，由於溫室效應的影響，冷凍空調設備的需求量也與日俱增，如何有效的提高冷凍空調系統的工作效率，即可大量的降低用電量。本研究是將噴霧裝置應用在複合式熱交換器上，探討各種不同的操作條件下，如噴霧顆粒大小、風扇吹否、不同型式的複合式熱交換器等，對於熱傳效率的影響，以找出最佳化的設計，應用在冷凍空調設備上。 研究的結果顯示複合式熱交換器(有裸露銅管)在噴霧顆粒較小及有風扇吹拂時的熱傳效果最好；在風扇不吹拂的情況下，噴霧顆粒較大的反而熱傳效果較好；只吹風不噴霧又比只噴霧不吹風的熱傳效果好。總體而言，噴霧裝置應用在熱交換器上，大大的提升了傳統熱交換器的熱傳效果。

Recently, due to the global warming caused by the green house effect of various gases, the need of refrigeration and air-conditioning has been increased day by day. Increasing the efficiency of the refrigeratiion and air-conditioning system could reduce the electrical power consumption directly. The objective of present study is to apply the swirl atomizer to spray fine droplets on the composite heat exchangers, in order to perform an investigation on the controlling parameters associated with the droplet diameter, the forced convective effect, the changes in the types of the heat exchangers, and the effect on the over all heat transfer rate. Optimal operating conditions adapt to the refrigeration and the air-conditioning system is to be found. According to the experimental results, the simultaneously effects of evaporation cooling with smaller spraying droplets and forced convection cooling could significantly enhance the heat transfer efficiency of the composite heat exchangers. But with no fan operating for forced convection, the heat transfer efficiency of spraying with the large droplets is better than the one with the small droplets. The efficiency of forced convection is better than spraying droplets when each one is operated alone. In conclusion, applying swirl atomizers to the composite heat exchanger could provide pronounced enhancement on its heat transfer efficiency.