Bu çalışmada iç ısı değiştiricili karbon dioksit soğutucu akışkanla (R744) çalışan kritik nokta üstü (transkritik) soğutma çevriminin tasarım parametrelerinin enerji ve ekserji verimine olan etkileri incelenmiştir. Tasarım parametreleri olarak genleşme elemanı çıkışında soğutucu akışkanın kuruluk derecesi ile iç ısı değiştiricisiyle sağlanan kızgınlık derecesi dikkate alınmıştır. Bu amaçla, iç ısı değiştiricili CO2 soğutma çevriminin tüm bileşenlerindeki enerji transferini, ekserji yıkımını, entropi üretimini ve ekserji verimini hesaplamak amacıyla buharlaşma sıcaklığı 0 oC ve yoğuşma basıncı 10 MPa alındı. Buna ek olarak, etkinlik katsayısı ile tüm sistemin ekserji verimi hesaplandı. 5 oC ve 30 oC kızgınlık değerlerinde en uygun kuruluk derecesi sırasıyla 0,42–0,47 ve 0,31–0,36 aralığında olduğu belirlendi.
This study examined the effects of the design parameters of the critical (transcritical) cooling circuit working with the internal heat-changing carbon dioxide cooling fluid (R744) on the energy and exergy output. As design parameters, the extension element output has been taken into account with the degree of drought of the coolant fluid and the degree of anger provided by the internal heat exchanger. For this purpose, the internal heat exchanger CO2 cooling circuit's energy transfer, exergy destruction, entropy production and exergy efficiency were calculated in order to calculate the evaporation temperature of 0 oC and the concentration pressure of 10 MPa. In addition, the output of the entire system was calculated with the performance ratio. The most suitable drought rate in the 5 oC and 30 oC anger values was determined at the range of 0.42-0.47 and 0.31-0.36 respectively.
In this study, effect of the design parameters of a transkritical refrigeration cycle using carbon dioxide refrigerant (R744) with internal heat exchanger on energy and exergy efficiencies were investigated. Quality of the refrigerant at the exit of the expansion valve and amount of superheating supplied by the internal heat exchanger were considered as design parameters. For this aim, in order to determine the energy transfer, the exergy destruction, entropy generation and exergy efficiency within the all components, the calculations were carried out at evaporation temperature of 0 oC and condensation pressure of 10 MPa. In addition to this, performance coefficient and the exergy efficiency of the whole system were calculated. The most suitable refrigerant qualities at superheating values of 5 oC and 30 oC were determined as between 0,42–0,47 and 0,31–0,36, respectively.
Alan : Mühendislik
Dergi Türü : Ulusal
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