Thermal Efficiency Comparison of Flat Plate and Evacuated Tube Solar Water Collectors

Flat plate and evacuated tube solar water collectors are widely used for supplying hot water for domestic and industrial applications in the world. However, there is no enough information regarding thermal efficiencies of different type solar water collectors for various environmental and climatic conditions. Therefore, in this work; thermal efficiencies of different types of flat plate solar water collector panels such as aluminum, copper, 304 chromium and evacuated tube have been compared. It was seen from the results that the efficiencies of aluminum and copper collector panels are changing between 56%...68% while the efficiencies of 304 stainless steel chromium panels are varied between 67%...88. In addition, evacuated tube type solar water collectors have less heat loss but lower absorber surface area to gross area ratio (about 70%) when compared with flat plate solar water collectors. Based on absorber surface area, evacuated tube type solar water collectors have more efficiency than equivalent flat plate collectors. However in practical applications, gross area of any solar water collector should be considered for comparison. In this case, the efficiencies of evacuated tube type solar water collectors are changing between 50%...70%. Besides, it should be kept in mind that evacuated tube type solar water collectors can be preferred for cold environmental and climatic conditions because of their less heat loss and cold resistant.

Anahtar Kelimeler:

Efficiency, solar water collector, flat plate, evacuated tube, aluminium, copper

___

Anonymous, 2003. EN (European Norms) 12972-2. Thermal solar systems and components-Solar collectors-Part 2: Test Methods, April, 2003.
Duffie J.A., and W.A. Beckman, 1991. Solar engineering of thermal process. John Wiley & Sons Ltd., New York.
Eames P.C., and P.W. Griffiths, 2006. Thermal behaviour of integrated solar collector/storage unit with 65 0C phase change material. Energy Conversion and Management, (47): 3611–3618
Enibe S.O., 2003 Thermal analysis of a natural circulation solar air heater with phase change material energy storage. Renewable Energy, (28): 2269–2299.
Hazami M., S. Kooli, M. Lazaar, A. Farhat and A. Belghith, 2005. Performance of a solar storage collector. Desalination, (183): 167-172.
Hussein H.M.S., H.H. El-Ghetany and S.A. Nada, 2008. Experimental investigation of novel indirect solar cooker with indoor PCM thermal storage and cooking unit. Energy Conversion and Management, (49): 2237–2246.
Kim Y., T. Seo, 2007. Thermal Performances Comparisons of the Glass Evacuated Tube Solar Collectors with Shapes of Absorber Tube. Renewable Energy, (32), 772-795.
Koyuncu T., 2002. Eğim Açılarının Düz Yüzeyli Hava Isıtıcı Güneş Kollektörlerinin Verimleri Üzerine Etkileri (in Turkish), O.M.Ü. Zir. Fak. Dergisi, 17 (3), 33-42.
Koyuncu T. 2006. Performance of various design of solar air heaters for crop drying applications. Renewable Energy, (31): 1073-1088.
Koyuncu T., Y. Pınar and F. Lule, 2007a. Efficiency of a Solar Water Heater System Widely Used for Domestic Applications in Turkey, The Third Int. Exergy, Energy and Environment Symposium (IEEES3 2007), 1-5 July, Evora, Portugal.
Koyuncu T., Y. Pınar and F. Lüle, 2007b. Doğal Dolaşımlı ve Kapalı Tip Güneşli Su Isıtıcı Sistemler İçin Kullanılan Eşanjörlerin Verimlerinin Belirlenmesi (in Turkish), Tarım Makinaları Bilimi Dergisi, 3, (3), 167-171.
Koyuncu T., F. Lule, Y. Pınar ve Y.B. Yurtlu, 2009. Basınçlı Açık Sistem Düz Yüzeyli Bir Güneş Kolektörünün Tasarımı, Yapımı ve Denenmesi (in Turkish), Tarımsal Mekanizasyon 25. Ulusal Kongresi, 129-137, Isparta, Türkiye.
Koyuncu T., Y. Pınar and F. Lule, 2011. The Effect of Some Components on Performance of Flat Plate Solar Water Collectors, Agricultural Mechanization in Asia, Africa and Latin America (AMA),42, (2), 37-44.
Koyuncu T., K.E. Engin, A.İ. Kaya, F. Lüle, M.F. Baran, N. Yükçü ve H. Soğukpınar, 2015a. Krom Bir Güneşli Su Isıtıcısının Tasarımı, Yapımı ve Denenmesi (in Turkish), Tarım Makinaları Bilimi Dergisi (Journal of Agricultural Machinery Science), 11, (1), 61-68. Koyuncu T., A.İ. Kaya ve K.E. Engin, 2015b. Adıyaman Yöresinde Kullanılan Oluklu Kolektörün Veriminin Belirlenmesi (in Turkish), 29. Ulusal Tarımsal Mekanizasyon ve Enerji Kongresi, 501-506, 2-5 Eylül, Diyarbakır, Türkiye.
Koyuncu T., F. Lule, 2016. Technical Features and Thermal Efficiencies of Various Flat Plate Solar Water Collectors. Environmental Science and Technology VII, (94), 14-22.
Kürklü A., A. Özmerzi and S. Bilgin, 2002. Thermal performance of a water-phase change material solar collector. Renewable Energy, (26): 391–399.
Ma L.,, Z. Lu, J. Zhang, R. Liang, 2010. Thermal Performance Analysis of the Glass Evacuated Tube Solar Collector with U-tube. Building and Environment, (45), 1959-1967.
Mazman M., L.F. Cabeza, H. Mehling, M. Nogues, H. Evliya and H.Ö. Paksoy, 2008. Utilization of phase change materials in solar domestic hot water systems. Renewable Energy, 1–5.
Nieuwoudt M. N,. and E. H. Mathews, 2005. A mobile solar water heater for rural housing in Southern Africa. Building and Environment, (40): 1217-1234.
Saman W., F. Buno and E. Halawa, 2005. Thermal performance of CM thermal storage unit for a roof integrated solar heating system. Solar Energy, (78):341–349.
Sharma A., V. V. Tyagi, C. R. Chen and D. Buddhi, 2007. Review on thermal energy storage with phase change materials and applications. Renewable and Sustainable Energy Reviews, (13): 318–345.
Shukla A., D. Buddhi and R.L. Sawhney, 2009. Solar water heaters with phase change material thermal energy storage medium: A review. Renewable and Sustainable Energy Reviews, (13): 2119–2125.
Talmatsky E., and A. Kribus, 2008. PCM storage for solar DHW: An unfulfilled promise?. Solar Energy, (82): 861–869. Zambolin E., D.Del Col, 2010. Experimental Analysis of Thermal Performance of Flat Plate and Evacuated Tube Solar Collectors in Stationary Standard and Daily Conditions. Solar Energy, (84), 1382-1396.
Zhang X.R., H. Yamaguchi, 2008. An Experimental Study on Evacuated Tube Solar Collector Using Supercritical CO2. Applied Thermal Engineering, (28), 1225-1233.
URL-1 : “https://www.google.com.tr/search?q= sun+ position&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjY06monoDTAhVGkRQKHa-tCLAQ_AUIBigB&biw= 1343&bih=633” Date : 31.03.2017
URL-2 : “https://www.google.com.tr/search?q= evacuated +tube+collectors&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj6yar3kv7SAhWE5xoKHaBjCoAQ_AUIBigB&biw=1343&bih=633” Date :30.03.2017