Performance and Economic Analysis of a Variable Refrigerant Flow (VRF) System

Öz

This study deals with the exergetic modeling and performance/cost evaluation of a variable refrigerant flow (VRF) air conditioning system. An experimental setup was established to investigate the system performance under cooling conditions. System mainly consists of one outdoor unit and two indoor units. Outdoor unit equipped with two compressors (one variable speed and one constant speed), condenser, and four way valve is connected to two indoor units. Exergy, cost, energy and mass (EXCEM) analysis was applied to this system for the first time to the best of the authors` knowledge. The relations between thermodynamic losses and capital costs were also parametrically investigated. Experimental results show that the greatest irreversibility (exergy destruction) occurs in the condenser, followed by the evaporators. Exergy efficiency of the whole system on the exergetic product/fuel basis was calculated to be 85.84% at a reference state temperature of 25 oC. Exergy efficiency and exergy loss rate were in the range of 85.27-86.55% and 0.919-0.916 MW/USD, respectively, based upon the conditions and parameters considered in the present study.

Anahtar Kelimeler

• Variable refrigerant flow,Energy analysis,Exergy analysis,Exergoeconomic

Değişken Soğutucu Akışkan Debili Bir Sistemin Performans ve Ekonomik Analizi

Öz

Bu çalışma kapsamında, değişken soğutucu akışkan debili (VRF) bir klima sisteminin ekserjetik modellemesi ve performans değerlendirmesi ele alınmıştır. Soğutma koşulları için sistem performansını araştırılabilmek için bir deney düzeneği kurulmuştur. Sistem esas olarak bir dış üniteden ve iki iç üniteden oluşmaktadır. Ġki adet kompresör (bir değişken hız ve bir sabit hız), konderser ve dört yollu valf ile donatılmış dış ünite, iki içi üniteye bağlanmıştır. Bu çalışmada sisteme ekserji, maliyet, enerji ve kütle (EXCEM) analizi uygulanmış ve termodinamik kayıplar ile maliyetler arasındaki ilişkiler parametrik olarak incelenmiştir. Deneysel sonuçlar, en büyük tersinmezliğin (ekserji tahribatının) kondenserde meydana geldiğini ve bunu evaporatörlerin izlediğini göstermektedir. Ekserjetik ürün/yakıt bazında sistemin ekserji verimi, 25 °C referans sıcaklığında % 85,84 olarak hesaplanmıştır. Bu çalışmada ele alınan koşullarda, sistemin ekserji verimi ve ekserji kayıp oranları sırasıyla % 85,27-86,55 ve 0,919-0,916 MW/USD aralığındadır.

Anahtar Kelimeler

• Değişken soğutucu akışkan debi,Enerji analizi,Ekserji analizi,Ekserjekonomi

Kaynakça

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