Bakır Kanatçıklı Ters Akışlı Isı Değiştirici Kullanılarak Atık Isının Geri Kazanımı Yoluyla Kombi Kazan Verimliliğinin Artırılması

Öz

Doğal gazla çalışan kombiler, konutların sıcak su ve ısınma ihtiyaçlarını karşılamak amacıyla yaygın olarak kullanılmaktadır. Atık ısı geri kazanımı, enerji verimliliğinin artırılması ve çevresel etkilerin azaltılması açısından önemli bir role sahiptir. Bu çalışmada, bakırın yüksek ısıl iletkenliği ve kanatçıklı yapıların sağladığı geniş yüzey alanı avantajlarından yararlanılarak geliştirilen çift borulu bir ısı değiştiricisi deneysel ve sayısal olarak incelenmiştir. Yanma odasına giren taze havanın önceden ısıtılması, suyun ısıtılması için gerekli yakıt miktarını azaltmaktadır. Bu amaçla, gelen taze hava ile dışarı atılan baca gazı arasındaki ısı transferi, boru sistemine bakır kanatçıklar eklenerek iyileştirilmiştir. Düz boru ve bakır kanatçıklı boru tasarımlarından elde edilen deneysel sonuçlar sayısal sonuçlarla karşılaştırılmıştır. Sonuçlar, baca gazı çıkış sıcaklığının yaklaşık %6 oranında azaldığını göstermiştir. Bakır kanatçık kullanımıyla ısı geri kazanım verimi %9,3'ten %14,8'e yükselmiş, kombi giriş havasındaki sıcaklık artışı ise 13 K'den 26 K'ye çıkmıştır. Sayısal ve deneysel sonuçlar arasında Nusselt sayısı ve sürtünme katsayısı açısından sırasıyla %4,77 ve %5,36 fark bulunmuştur. Bakır kanatçıkların sağladığı iyileştirilmiş ısı transferi sonucunda Nusselt sayısında %3,98 artış elde edilmiştir.

Anahtar Kelimeler

• Atık Isı Geri Kazanımı
• Isı Transferi
• Bakır Kanatçık
• Boru Çifti
• Isı Değiştirici

Enhancing Combi Boiler Efficiency through Waste Heat Recovery Using a Copper-Finned Counter-Flow Heat Exchanger

Öz

Natural gas-fired combi boilers are widely used to meet domestic hot water and space heating demands. Waste heat recovery is important for improving energy efficiency and reducing environmental impacts. In this study, a double-pipe heat exchanger utilizing copper's high thermal conductivity and the large surface area provided by finned structures was experimentally and numerically investigated. Preheating the fresh air supplied to the combustion chamber decreases the fuel required for water heating. Heat transfer between the incoming fresh air and outgoing flue gases was enhanced by incorporating copper fins into the pipe assembly. Experimental results obtained from straight and copper-finned pipe configurations were compared with numerical predictions. The results showed that the flue gas outlet temperature decreased by approximately 6%. Heat recovery efficiency increased from 9.3% to 14.8% with the use of copper fins, while the inlet air temperature increased from 13 K to 26 K. Numerical and experimental results agreed well, with differences of 4.77% and 5.36% for the Nusselt number and friction factor, respectively. The enhanced heat transfer provided by copper fins resulted in a 3.98% increase in the Nusselt number.

Anahtar Kelimeler

• Waste Heat recovery
• Heat Transfer
• Cooper Fins
• Double Pipe
• Heat Exchanger

Kaynakça

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