Comparison of superheating effect of water as a refrigerant with the other refrigerants

Su (R718) soğutucu akışkan olarak, R717, R290, R134a ve R152a gibi soğutucu akışkanlarla performans açısından buhar sıkıştırmalı bir soğutma sisteminde kıyaslanmıştır. Aşırı ısıtmanın olduğu buhar sıkıştırmalı soğutma çevriminin simülasyonunu yapan bir bilgisayar programı geliştirilerek kullanılan soğutucu akışkanlar için çevrimin soğutma tesir katsayısı (STK) hesaplanmıştır. Farklı aşırı ısıtma durumları için, su’yun diğer soğutucu akışkanlara göre daha yüksek STK değerlerini verdiği buharlaştırma sıcaklıkları araştırılmıştır. Aşırı ısıtmanın STK üzerindeki etkileri araştırılmıştır. Artan buharlaştırıcı sıcaklıklarında, R718’in bağıl STK değerinde keskin bir artma görülmüştür. Sabit buharlaştırıcı sıcaklıklarında, aşırı ısıtma derecesi arttığında R718’in mutlak STK değeri artmaktadır. Yoğuşturucu sıcaklığı ve politropik verim sabit tutulduğunda, 26˚C’nin üzerindeki buharlaştırıcı sıcaklıklarında yüksek aşırı ısıtma değerlerinde (6K-8K), R718’in en yüksek bağıl STK artışını verdiği tespit edilmiştir.

Suyun soğutucu akışkan olarak aşırı ısıtma etkisinin diğer akışkanlarla kıyaslanması

The performance comparison of water as a refrigerant (R718) with some refrigerants including R717, R290, R134a, and R152a is presented for a vapor compression refrigeration cycle. A computer program simulating the vapor compression refrigeration cycle including superheating was developed to calculate the coefficient of performances (COPs) for the refrigerants. Evaporator temperatures which water yields a better COP over the other refrigerants are investigated for different superheating cases. The effects of degree of superheating on the COPs are observed. R718 shows the steepest increase in the relative COP gain with increasing evaporator temperature. At constant evaporator temperatures, the absolute COP of R718 increases as the degree of superheating increases. It is found that for evaporator temperatures above 26˚C and high degree of superheating (6K-8K), R718 gives the highest relative COP increase at constant condenser temperature and polytropic efficiency.

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