Thermodynamic and Exergy Analysis of an Absorptıon Cooling System for Different Refrigerants

Öz

In absorption cooling systems, the compression of the working fluid is not made by the compressor but by a system consisting of absorbers, pumps and generators. The fact that the compressor is not used for compression reduces the power required for this process. In this case, absorption cooling systems are very useful when used with renewable energy sources. In this study, thermodynamic and exergy analysis of the system was performed to see the effects of different refrigerant solutions on the performance of an absorption cooling system. In the absorption cooling system for Lithium bromide-Water (LiBr-H₂O), ammonia-water (NH₃-H₂O), ammonia-lithium nitrate (NH₃-LiNO₃) and ammonia-sodium thiocyanate (NH₃-NaSCN) fluid couples, the Coefficient of Performance (COP) and Exergy Efficiency (%) of the system were examined for each fluid pair by analyzing at different generator, evaporator and absorber temperatures. Analysis results indicate that the LiBr-H₂O solution pair showed better performance (higher COP and exergy efficiency) than the other solution pairs (NH₃-H₂O, NH₃-LiNO₃, NH₃-NaSCN).

Anahtar Kelimeler

• Exergy,ammonia/NH3,LiBr/H2O,ammonia/NaSCN,absorption refrigeration system

Farklı Soğutucu Akışkanlar için Bir Absorbsiyonlu Soğutma Sisteminin Termodinamik ve Ekserji Analizi

Öz

Absorpsiyonlu soğutma sistemlerinde çalışma akışkanının sıkıştırma işlemi kompresörle değil absorber, pompa ve generatörden oluşan bir sistemle yapılmaktadır. Sıkıştırma işlemi için kompresör kullanılmaması bu işlem için ihtiyaç duyulan gücü azaltmaktadır. Bu durumda absorbsiyonlu soğutma sistemleri yenilenebilir enerji kaynakları ile kullanıldığında oldukça kullanışlı olmaktadır. Bu çalışmada farklı soğutucu akışkan çözeltilerinin bir absorpsiyonlu soğutma sisteminin performansı üzerindeki etkilerini görebilmek için sistemin termodinamik ve ekserji analizi yapılmıştır. Lityum bromür-Su (LiBr-H₂0), amonyak-su (NH₃-H₂0), amonyak-lityum nitrat (NH₃-LiNO₃) ve amonyak-sodyum tiyosiyanat (NH₃-NaSCN) akışkan çiftleri için absorbsiyonlu soğutma sisteminde farklı jeneratör, buharlaştırıcı ve absorber sıcaklıklarında analiz yapılarak sistemin Soğutma Tesir Katsayısı (STK) ve Ekserji Verimleri (%) her bir akışkan çifti için incelenmiştir. Analiz sonuçları LiBr-H₂O çözelti çiftinin diğer akışkan çiftlerine (NH₃-H₂O, NH₃-LiNO₃, NH₃-NaSCN) göre daha iyi bir performansa sahip olduğunu göstermiştir.

Anahtar Kelimeler

• Ekserji,NH3,LiBr/H2O,NH3/NaSCN,absobsiyonlu soğutma sistemi

Kaynakça

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