Highlights• 1/2" smooth tube and 3/8" grooved tube types evaporators are designed for industrial refrigerators.• Theoretical and experimental analysis and comparison of smooth and grooved tube evaporators.• The system COP value is 2.807, while it is calculated as 3.013 for the second system.• The grooved tube evaporator has better cooling performance compared to the smooth tube evaporator.
Süpermarketlerde teşhir tipi plug-in soğutucular yaygın olarak kullanılmaktadır. Bu soğutucularda şebekeye bağlı drenaj sistemi bulunmadığından, biriken defrost suyu PTC rezistans yardımı ile uzaklaştırılmaktadır. PTC rezistansının enerji tüketimi toplam enerji tüketiminin yaklaşık %20’sini oluşturmaktadır. Nihai enerji tüketiminin birincil enerji kaynaklarından karşılandığı düşünüldüğünde; fosil yakıtların azalması ve enerji maliyetlerinin artması ile tüketilen enerjinin daha verimli kullanılması gerekmektedir. Bu çalışmada, kompresör çıkışında kızgın buhar halindeki soğutucu akışkan kompresör basma hattı boruları ile defrost kabında bulunan durgun su içerisinden geçirilmiştir. Defrost kabı içerisinde bulunan basma borularına ilave kanatçıklar eklenerek ısı transferi artırılmış ve enerji tüketimi azaltılmıştır. Bu sayede soğutucunun enerji tüketimi azaltılarak mevcut sistemde “E” olan enerji sınıfı yeni tasarım ile “D” sınıfına yükseltilmiştir. Böylece çevre dostu bir tasarım ortaya koyulmuş ve birincil enerji tüketimi düşürülerek 1 adet soğutucu için 11,138 kg/gün CO2 emisyonu azaltılmıştır.
Efficiency is becoming an increasingly important issue in cooling systems. It is important to use micro channel heat exchangers in order to increase the cooling system efficiency. In this study, performance analysis of refrigerants used in supermarkets was tested experimentally. Thermodynamic analyses of the refrigerants were examined. The compatibility of R290 and R449A refrigerants with the environment has been experimentally observed. Energy, exergy, and environmental analyses were performed using R290 and R449a refrigerants based on the test results for 24 hours using double inlet and double outlet evaporator. Accordingly, in the experiments using R290, the exergy efficiency and COP value are 43.52 % and 2.09, respectively. In experiments using R449A, these values were found to be 22.28 % and 1.59. Exergy efficiency was increased by 48.81 % in experiments using propane. In addition, an increase of 24.12% was observed in the Coefficient of Performance (COP) value. Considering the environmental analysis results, the amount of CO2 emitted by the R290 refrigerant to the atmosphere during the test period was 3.14 kg/h and R449A was calculated as 3.97 kg/h. It was seen in this study that the R290 refrigerant emits 26.22 % less CO2 to the atmosphere.
Air flow is of great importance in terms of energy efficiency and homogeneity of the cooled package temperatures in open type refrigerated display cabinets (RDCs). Deflectors are critical components for air curtains which are provides air directioning to air channel and grill. A new deflector structure was investigated to increase the performance of the air curtain in this study. Current design deflector structure (Design 1) and new design deflector structure (Design 2) were compared for temperatures of air off-air on and energy consumption parameters. Airflow in the new design deflector structure was tested under Class-3 conditions (25 °C temperature and %60 relative humidity) with ISO 23953-2 2015 standard. According to the results obtained the data compared with the current design deflector structure. The thermal performance has been increased by reducing the temperature of the air off by 1.2 °C on average, the air on temperature by an average of 2.05 °C and the average package temperature by %17.8 with the new deflector design. Cooling performance was increased using new deflector structure with effective airflow between the air off and air on. In addition, thanks to Design 2, the annual energy consumption of RDC has been reduced by 10.17% and accordingly the CO2 emissions released to the environment have been reduced at the same rate.
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