Transkritik R744 ve R404A kullanan soğutma çevrimi sistemlerinin performansının gıdaların hızlı soğutulmasında deneysel olarak karşılaştırılması
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Tarih
2024
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Yayıncı
Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Yaşamın bir parçası olan beslenme faaliyetini gerçekleştirebilmek her canlı için hayati önem taşımaktadır. İnsanoğlunun bu besinlere ulaşması ise ürünlerin kısa sürede soğutulması ve son kullanıcıya ulaştırılması için uzun süre muhafaza edilebilmesine bağlıdır. Endüstriyel soğutma ekipmanları bu koşulları sağlamak için kullanılan temel araçlardan biridir. Örneğin, endüstriyel soğutma odaları ve buzdolapları, gıda ürünlerinin düşük sıcaklıkta depolanmasını sağlayarak mikrobiyal büyümeyi kontrol altında tutar ve ürünlerin raf ömrünü uzatır. Bu soğutma işlemi besinler için birden fazla soğutucu akışkanla gerçekleştirilebilir. HFC ve HFO sistemlerinin yanı sıra, kullanımı yaygın olan bu sistemlerin küresel ısınmaya etkisini azaltmak amacıyla CO2 akışkanlı soğutma çevrimleri geliştirilmiştir. Bu tez çalışmasının hedefi benzer koşullardaki R404A soğutucu akışkanlı sistem ile performansı yüksek, ekonomik olarak uygulanabilir ve doğa dostu olmasıyla öne çıkan transkritik CO2 (R744) akışkanlı soğutma çevrimi deneysel olarak incelenmiştir. R744 soğutucu akışkanlı sistem transkritik çalışacak şekilde dizayn edilmiştir. R404A soğutucu akışkanlı sistemden farklı olarak gas cooler kullanılmıştır. Deney sırasında takip edilen parametreler; başlangıç saati, bitiş saati, soğutma süresi, başlangıç basıncı, ortam sıcaklığı, dolap içi sıcaklığı, evaporasyon sıcaklığı, evaporasyon basıncı, kompresör soğutma kapasitesi ve sistemin tükettiği enerjidir. Deney sisteminde kullanılan şoklama kabini iç net ölçüleri: 73,025 cm x 68,9102 cm x 185,42 cm şeklindedir. İlk olarak, R404A soğutucu akışkanlı cihazda şoklanan ürün miktarı 80 kilogram olarak belirlenmiştir. Soğutma kabinine giren ürününün giriş sıcaklığı ~80 °C, ürünün çıkış sıcaklığı, -6,1 °C olarak ölçülmüştür. -20 °C evaporasyonda ve 19 bar 45 °C kondenzasyonda çalıştırılmıştır. Sistemin soğutma kapasitesi ortalama olarak 11,24 kW, ortalama enerji tüketimi 7,21 kW ve COP değeri 1,55 olarak hesaplanmıştır. R744 (CO2) soğutucu akışkanlı cihazda şoklanan ürün miktarının da aynı olması adına 80 kilogram olarak belirlenmiştir. Bu cihazda ürün giriş sıcaklığı ~80 °C, ürün çıkış sıcaklığı -8,33 °C olarak belirlenmiştir. Cihazın çalışma şartları; evaporasyon sıcaklığı -20 °C, gaz cooler çıkış sıcaklığı 35 °C, çıkış basıncı ortalama 90 bar olarak ölçülmüştür. Sistemin soğutma kapasitesi ortalama olarak 10,72 kW, ortalama enerji tüketimi 8,84 kW ve COP değeri 1,21 olarak hesaplanmıştır. Yaklaşık olarak aynı soğutma kapasitesine sahip iki farklı soğutucu akışkanın deneyleri yapılarak verimleri karşılaştırılmıştır.
It is vital for every living being to be able to realize the activity of nutrition, which is a part of life. Human beings' access to these nutrients depends on the ability to cool the products in a short time and to preserve them for a long time to be delivered to the end user. Industrial refrigeration equipment is one of the main tools used to provide these conditions. For example, industrial cooling chambers and refrigerators allow food products to be stored at low temperatures, keeping microbial growth under control and extending the shelf life of products. This cooling process can be accomplished with multiple refrigerants for food. In addition to HFC and HFO systems, CO2 refrigeration cycles have been developed to reduce the global warming impact of these widely used systems. The aim of this thesis is to experimentally investigate the transcritical CO2 (R744) refrigeration cycle, which stands out with its high performance, economically feasible and environmentally friendly, with the R404A refrigerant system under similar conditions. The system with R744 refrigerant is designed to operate transcritically. Unlike the system with R404A refrigerant, a gas cooler was used. The parameters monitored during the experiment are; start time, end time, cooling time, start pressure, ambient temperature, temperature inside the cabinet, evaporation temperature, evaporation pressure, compressor cooling capacity and energy consumed by the system. Internal net dimensions of the shocking cabinet used in the experimental system: 73.025 cm x 68.9102 cm x 185.42 cm. First, the amount of product shocked in the device with R404A refrigerant was determined as 80 kilograms. The inlet temperature of the product entering the cooling cabinet was ~80 °C and the outlet temperature of the product was measured as -6.1 °C. It was operated at -20 °C evaporation and 19 bar 45 °C condensation. The cooling capacity of the system was calculated as 11.24 kW on average, the average energy consumption was 7.21 kW and the COP value was 1.55. The amount of product shocked in the device with R744 (CO2) refrigerant was determined as 80 kilograms in order to be the same. In this device, the product inlet temperature is ~80 °C and the product outlet temperature is -8.33 °C. Operating conditions of the device; evaporation temperature -20 °C, gas cooler outlet temperature 35 °C, outlet pressure was measured as 90 bar on average. The cooling capacity of the system was calculated as 10.72 kW, average energy consumption as 8.84 kW and COP value as 1.21. Two different refrigerants with approximately the same cooling capacity were tested and their efficiencies were compared.
It is vital for every living being to be able to realize the activity of nutrition, which is a part of life. Human beings' access to these nutrients depends on the ability to cool the products in a short time and to preserve them for a long time to be delivered to the end user. Industrial refrigeration equipment is one of the main tools used to provide these conditions. For example, industrial cooling chambers and refrigerators allow food products to be stored at low temperatures, keeping microbial growth under control and extending the shelf life of products. This cooling process can be accomplished with multiple refrigerants for food. In addition to HFC and HFO systems, CO2 refrigeration cycles have been developed to reduce the global warming impact of these widely used systems. The aim of this thesis is to experimentally investigate the transcritical CO2 (R744) refrigeration cycle, which stands out with its high performance, economically feasible and environmentally friendly, with the R404A refrigerant system under similar conditions. The system with R744 refrigerant is designed to operate transcritically. Unlike the system with R404A refrigerant, a gas cooler was used. The parameters monitored during the experiment are; start time, end time, cooling time, start pressure, ambient temperature, temperature inside the cabinet, evaporation temperature, evaporation pressure, compressor cooling capacity and energy consumed by the system. Internal net dimensions of the shocking cabinet used in the experimental system: 73.025 cm x 68.9102 cm x 185.42 cm. First, the amount of product shocked in the device with R404A refrigerant was determined as 80 kilograms. The inlet temperature of the product entering the cooling cabinet was ~80 °C and the outlet temperature of the product was measured as -6.1 °C. It was operated at -20 °C evaporation and 19 bar 45 °C condensation. The cooling capacity of the system was calculated as 11.24 kW on average, the average energy consumption was 7.21 kW and the COP value was 1.55. The amount of product shocked in the device with R744 (CO2) refrigerant was determined as 80 kilograms in order to be the same. In this device, the product inlet temperature is ~80 °C and the product outlet temperature is -8.33 °C. Operating conditions of the device; evaporation temperature -20 °C, gas cooler outlet temperature 35 °C, outlet pressure was measured as 90 bar on average. The cooling capacity of the system was calculated as 10.72 kW, average energy consumption as 8.84 kW and COP value as 1.21. Two different refrigerants with approximately the same cooling capacity were tested and their efficiencies were compared.
Açıklama
Anahtar Kelimeler
Chemistry, Kimya Mühendisliği, Kimya, Chemical Engineering
