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    Öğe
    Buhar sıkıştırmalı bir soğutma sisteminde R22 yerine N20 ve R444B soğutucu akışkanlarını kullanmanın termodinamik performansa etkisi
    (2016) Devecioğlu, Atilla Gencer; Oruç, Vedat
    Bu çalışmada buhar sıkıştırmalı bir soğutma sisteminde R22 soğutucu akışkanı yerine N20 ve L20 (R444B) soğutucu akışkanının kullanılmasıyla enerji ve ekserji parametreleri teorik olarak incelenmiştir. Aynı çalışma şartları altında farklı evaporasyon sıcaklıkları (-15?C, -10?C, -5?C, 0?C) ve kondenser sıcaklıkları (30?C, 40?C, 50?C) için enerji parametrelerin mukayesesi yapılmıştır. Üç soğutucu akışkan için de performans katsayılarının (COP) aynı mertebede olduğu görülmüş ancak en yüksek COP değeri R22 durumunda elde edilmiştir. N20 veya R444B kullanacak olan cihazların, R22 ile çalışan sistemlere göre daha büyük kondenser yüzey alanlarının olması gerektiği anlaşılmıştır. İncelenen soğutucu akışkanlar içerisinde R22'nin ekserji veriminin daha yüksek olduğu tespit edilmiştir.
  • Küçük Resim
    Öğe
    Energetic performance analysis of R466A as an alternative to R410A in VRF systems
    (Elsevier B.V., 2020) Devecioğlu, Atilla Gencer; Oruç, Vedat
    In this study, utilization of R466A with low-GWP is investigated in variable refrigerant flow (VRF) systems. R410A is widely used in VRF systems. Only non-flammable refrigerants are allowed for these systems since they require high amount of refrigerant charge. However, most of refrigerants, which have low-GWP and may be suitable for air-conditioning systems, are flammable. The analysis was carried out for both cases of cooling mode and heating mode. Three evaporation temperatures (4, 8 and 12 °C) and three condenser temperatures (40, 50, 60 °C) were considered for cooling mode in the study. In heating mode, three different evaporation temperature values (−10, −5 and 0 °C) while single condenser temperature of 45 °C were used for the investigation. The results pointed out that both cooling capacity and heating capacity amounts of R466A were greater in comparison with R410A. COP values of R466A were determined as higher than R410A about by 5–15% and 4% in cooling mode and heating mode, respectively. Thus, R466A can be utilized as a suitable refrigerant for VRF systems and air-conditioners as an alternative to R410A. In the short term, R466A can be directly used without performing any constructional modification in the system operating with R410A.
  • Küçük Resim
    Öğe
    Experimental and numerical analysis of a parabolic trough solar collector for water heating application
    (Taylor & Francis, 2022) Özcan, Abdulkadir; Devecioğlu, Atilla Gencer; Oruç, Vedat
    The aim of this study is to obtain hot water utilizing a parabolic trough solar collector. The copper tube and aluminum absorber tube were placed separately through the focus point of the parabolic reflector. The steady mass flow rate of water was changed for five cases of 0.0017 to 0.0083 kg/s and the thermal efficiency of the system was computed for each absorber tube. The amount of solar radiation, mass flow rate as well as water temperatures at inlet and outlet of the absorber tube were measured during the investigation to have the experimental data. The maximum efficiency values were found as 74.5% for copper tube absorber while it was 72.7% for copper tube absorber when mass flow rate was 0.0083 kg/s. The problem was also modeled with CFD and temperatures at the outlet of absorber tube were found by numerical simulations (area-weighted average method) which showed a deviation of 6.5% as an average compared to experimental results.
  • [ X ]
    Öğe
    Hcfc-22 yerine alternatif soğutucu akışkanların kullanıldığı split klima sistemlerinin enerji parametrelerinin araştırılması
    (2014) Berk, Uğur; Vural, İbrahim; Devecioğlu, Atilla Gencer; Oruç, Vedat
    [Abstract Not Available]