Taşıt kliması performansının deneysel araştırılması
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Dosyalar
Tarih
2012-05-21
Yazarlar
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Yayıncı
Selçuk Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
aşıt sistemlerinin temel bir parçası olan otomobil klimalarının insan konforunda ve üretkenliğinde önemli bir yeri vardır. Bu çalışmada, R134a soğutucu akışkan kullanan bir minibüsteki klima sisteminin deneysel performansı incelendi. Sistem buhar sıkıştırmalı soğutma çevrimine göre çalışmaktadır. Tasarlanan sistem otomobil kliması kompresörünün şaft gücüyle eşdeğer kapasitede olan bir elektrik motoru ile tahrik edildi. Kompresör, kondenser genleşme valfi ve evaporatörün giriş ve çıkışında basınç ve sıcaklık değerleri ölçüldü. Ayrıca, evaporatör girişinde kütlesel hava debisi ve bağıl nem de ölçülmüştür. Ölçümler her saniyede bir kez kayıt altına alındı ve bu ölçümlerin 10 dakikalık değerlerinin ortalamaları hesaplandı. Ölçüm değerlerinden taşıt klimasının soğutma kapasitesi ve soğutma tesir katsayıları hesaplandı. Soğutma sistemi performans değerleri evaporatörden geçen havanın hacimsel debisinin değişimine göre incelendi. Soğutma kapasitelerinde üfleme havasının etkisini belirlemek için evaporatörün girişinde havanın sıcaklığı 30 °C de sabit tutularak sistem 3 farklı hava hızı değerinde (3.0 m/s, 5.0 m/s ve 10 m/s) çalıştırıldı. Bu esnada, evaporatör, kondenser, kompresör ve minibüsün içerisinde değişik noktalardaki sıcaklık ve basınç değerleri kaydedildi. Elde edilen sonuçlar grafik ve tablo formunda verilerek yorumlandı. Buralardan elde edilen sonuçlara göre minimum evaporatör kapasitesi 3.0 m/s deki hava hızında 1.46 kW olarak bulundu. Maksimum evaporatör kapasitesi de 10 m/s deki hava hızında 4.23 kW olarak hesaplandı. Bu sonuçlara göre hava hızı doğrusal olarak arttıkça evaporatör kapasitesinin değişimi parabolik bir artış göstermiştir. Soğutucu akışkanın debisi 9-29 g/s arasında değişim gösterdi. Maksimum kompresör gücü 10 m/s deki hava hızında 1.811 kW olarak bulundu. Sistemin soğutma etkinliği katsayısı 2.06 ? 5.10 arasında değişmiştir. Ölçülen değerlerden kompresörün farklı devirleri için ekserji yıkım değişimi 0.337 - 1.869 kW aralığında hesaplanmıştır. Yapılan ölçümlerden hesaplanan soğutma tesir katsayısındaki belirsizlik ±% 2.8-4.1 arasında bulundu. Sonuç olarak elde edilen değerlerin, literatürde verilen taşıt kliması performans değerleri ile uyumlu olduğu görülmüştür.
Automotive air-conditioning (A/C) system that is an essential part of the vehicle plays important role in human comfort and productivity. In this study, performance experiments of air conditioning system using R134a as refrigerant in a van was carried out. The system operates according to the vapor compression cycle and is powered by an electric motor that has an equivalence capacity of shaft power of the vehicle air conditioner compressor. At inlet and outlet of the compressor, condenser, expansion valve and evaporator, pressure and temperature values were measured and additionally air mass flow rate and relative humidity were measured through evaporator air channel. Measurements were taken each second and calculations were done using mean value of ten minutes measurement values. Performance of the cooling system was determined by changing air flow velocity in the range of 3.0 m/s-10 m/s passing through evaporator while air entrance temperature was kept constant as 30 °C. The obtained results were interpreted and given in graphical and table forms. In order to determine the effect of blowing air velocity on the cooling capacity, the system was operated for the conditioned air velocity values of 3.0, 5.0 and 10 m/s while pressure and temperature variations through the evaporator, condenser, compressor and inside of the van were recorded. It was obtained that the minimum evaporator capacity was found to be 1.46 kW at 3 m/s conditioned air speed and the maximum evaporator capacity was determined as 4.23 kW at 10 m/s conditioned air velocity. Maximum compressor power was found to be 1.811 kW at 10 m/s air speed. Coefficient of performance (COP) value of the system was calculated in the range of 2.06- 5.10 depending on the compressor speed and air velocity. When air velocity increases linearly, evaporator capacity increases in a parabolic trend. Flow rate of the refrigerant R134a was changed between 9 and 29 g/s. An exergy analysis of the measurement results was also done and the destruction ratio depending on engine speed was in the range of 0.337 - 1.869 kW. Uncertainty values from the measurement parameters for the COP were found to be in the range of ±% 2.8-4.1. Finally, it is seen that the obtained values were in good agreement with literature.
Automotive air-conditioning (A/C) system that is an essential part of the vehicle plays important role in human comfort and productivity. In this study, performance experiments of air conditioning system using R134a as refrigerant in a van was carried out. The system operates according to the vapor compression cycle and is powered by an electric motor that has an equivalence capacity of shaft power of the vehicle air conditioner compressor. At inlet and outlet of the compressor, condenser, expansion valve and evaporator, pressure and temperature values were measured and additionally air mass flow rate and relative humidity were measured through evaporator air channel. Measurements were taken each second and calculations were done using mean value of ten minutes measurement values. Performance of the cooling system was determined by changing air flow velocity in the range of 3.0 m/s-10 m/s passing through evaporator while air entrance temperature was kept constant as 30 °C. The obtained results were interpreted and given in graphical and table forms. In order to determine the effect of blowing air velocity on the cooling capacity, the system was operated for the conditioned air velocity values of 3.0, 5.0 and 10 m/s while pressure and temperature variations through the evaporator, condenser, compressor and inside of the van were recorded. It was obtained that the minimum evaporator capacity was found to be 1.46 kW at 3 m/s conditioned air speed and the maximum evaporator capacity was determined as 4.23 kW at 10 m/s conditioned air velocity. Maximum compressor power was found to be 1.811 kW at 10 m/s air speed. Coefficient of performance (COP) value of the system was calculated in the range of 2.06- 5.10 depending on the compressor speed and air velocity. When air velocity increases linearly, evaporator capacity increases in a parabolic trend. Flow rate of the refrigerant R134a was changed between 9 and 29 g/s. An exergy analysis of the measurement results was also done and the destruction ratio depending on engine speed was in the range of 0.337 - 1.869 kW. Uncertainty values from the measurement parameters for the COP were found to be in the range of ±% 2.8-4.1. Finally, it is seen that the obtained values were in good agreement with literature.
Açıklama
Anahtar Kelimeler
COP, Ekserji, Hava akış debisi, Otomotiv Kliması, R134a, Soğutma, STK, Air flow rate, Automobile air conditioning, Exergy, Refrigeration
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Özmen, R. (2012). Taşıt kliması performansının deneysel araştırılması. Selçuk Üniversitesi, Yayımlanmış yüksek lisans tezi, Konya.
