Politeknik Dergisi 2147-9429 Gazi University 10.2339/politeknik.407258 Engineering Mühendislik Experimental Study of Thermal Performance and Pressure Differences of Different Working Fluids in Two-phase Closed Thermosyphons Using Solar Energy Experimental Study of Thermal Performance and Pressure Differences of Different Working Fluids in Two-phase Closed Thermosyphons Using Solar Energy Özbaş Engin 03 01 2019 22 1 121 128 02 20 2017 Copyright © 1998, Journal of Polytechnic 1998 Journal of Polytechnic

An experimental study is carried out to investigatethe pressure distribution and thermal performance of gravity assisted heat pipecharged with different working fluids. Methanol, water and Mono-Ethylene-Glycol(MEG) are chosen as working fluids which have different boiling point, densityand viscosity. An experimental test apparatus is designed and produced includingthree heat pipes that heat input on the evaporator section are provided bysolar energy. Measurements are conducted on the heat pipe surface for pressureand temperature variations. Pure antifreeze is chosen as working fluid, due toits high boiling point, along with water and methanol which are widely used inthermosyphon type heat pipes. Heat pipes are put into parabolic focusedvacuumed glass tube and operated by solar energy for 11 days in order toachieve high temperatures. Data taken from 06.30 to 18.30 is taken intoconsideration for experimental results. Experimental results are evaluated fortwo days as (i) sunny and (ii) cloudy days by choosing days with the highestand lowest solar radiation.  (i) As forthe sunny day, the highest storage water temperatures for methanol, water andantifreeze were 90.0°C, 83.5°C and 86.7°C and the pressure values were 6.7 bar,1.6 bar and 1.9 bar respectively. (ii) And for the cloudy day, the respectivevalues of temperature and pressure were measured as; 43.9°C, 39.3°C, 29.0°C,and 2.0 bar, 0.2 bar and -0.3 bar.

An experimental study is carried out to investigatethe pressure distribution and thermal performance of gravity assisted heat pipecharged with different working fluids. Methanol, water and Mono-Ethylene-Glycol(MEG) are chosen as working fluids which have different boiling point, densityand viscosity. An experimental test apparatus is designed and produced includingthree heat pipes that heat input on the evaporator section are provided bysolar energy. Measurements are conducted on the heat pipe surface for pressureand temperature variations. Pure antifreeze is chosen as working fluid, due toits high boiling point, along with water and methanol which are widely used inthermosyphon type heat pipes. Heat pipes are put into parabolic focusedvacuumed glass tube and operated by solar energy for 11 days in order toachieve high temperatures. Data taken from 06.30 to 18.30 is taken intoconsideration for experimental results. Experimental results are evaluated fortwo days as (i) sunny and (ii) cloudy days by choosing days with the highestand lowest solar radiation.  (i) As forthe sunny day, the highest storage water temperatures for methanol, water andantifreeze were 90.0°C, 83.5°C and 86.7°C and the pressure values were 6.7 bar,1.6 bar and 1.9 bar respectively. (ii) And for the cloudy day, the respectivevalues of temperature and pressure were measured as; 43.9°C, 39.3°C, 29.0°C,and 2.0 bar, 0.2 bar and -0.3 bar.

 Heat pipe solar energy heating performance Heat pipe solar energy heating performance [1] Leriche M., Harmand S., Lippert M., Desmet B., “An experimental and analytical study of a variable conductance heat pipe: Application to vehicle thermal management”, Applied Thermal Engineering, 38: 48-57, (2012). [2] Chan C.W., Siqueiros E., Ling-Chin J., Royapoor M., Roskilly A.P., “Heat utilization technologies: A critical review of heat pipes”, Renewable and Sustainable Energy Reviews, 50: 615-627, (2015). [3] Zohuri B., Heat Pipe Design and Technology, CRC Press (2011). [4] Jahanbakhsh A., Haghgou H.R., Alizadeh S., “Experimental analysis of a heat pipe operated solar collector using water-ethanol solution as the working fluid”, Solar Energy, 118: 267-275, (2015). [5] Yang X., Yan Y.Y., Mullen D., “Recent developments of lightweight, high performance heat pipes”, Applied Thermal Engineering, 33-34: 1-14, (2012). [6] Vasiliev L., Vasiliev Jr L., “Sorption heat pipe-a new thermal control device for space and ground application”, International Journal of Heat and Mass Transfer, 48: 2464-2472, (2005). [7] Vasiliev L.L., Kakac S., “Heat pipe and solid sorption transformation, fundamentals and practical applications”, Taylor&Francis Group, LLC (2013). [8] Jafari D., Franco A., Filippeschi S., Di Marco P., “Two-phase closed thermosyphons: A review of studies and solar applications”, Renewable and Sustainable Energy Reviews, 53: 575-593, (2016). [9] Franco A., Filippeschi S., “Closed loop two-phase thermosyphon of small dimensions: are view of the experimental results”, Microgravity Science and Technology, 24: 165-179, (2012). [10] Filippeschi S., “Comparison between miniature periodic two-phase thermosyphons and miniature LHP applied to electronic cooling equipment”, Applied Thermal Engineering, 31: 795-802, (2011). [11] Reay D.A., Kew P., “Heat pipes (5th edition)”, Oxford, UK, Butterworth-Heinemann, (2006). [12] Faghri A., “Heat Pipe Science and Technology”, Taylor & Francis, Washington, DC, (1995). [13] Gedik E., Yılmaz M., Kurt H., “Experimental investigation on the thermal performance of heat recovery system with gravity assisted heat pipe charged with R134a and R410a”, Applied Thermal Engineering, 99: 334-342, (2016). [14] Abreu S.L., Colle S., “An experimental study of two-phase closed thermosyphons for compact solar domestic hot-water systems”, Solar Energy, 76: 141-145, (2004). [15] Chun W., Kang Y.H., Kwak H.Y., Lee Y.S., “An experimental study of the utilization of heat pipes for solar water heaters”, Applied Thermal Engineering, 19: 807-817, (1999). [16] Esen M., Esen H., “Experimental investigation of a two-phase closed thermosyphon solar water heater”, Solar Energy, 79: 459-468, (2005). [17] Nuntaphan A., Tiansuwan J., Kiatsiriroat T., “Enhancement of heat transport in thermosyphon air preheater at high temperature with binary working fluid: A case study of TEG–water”, Applied Thermal Engineering, 22: 251-266, (2002). [18] Yue H., Zhao Y., Ma X., Gong J., “Ethylene glycol: properties, synthesis, and applications”, Chemical Society Reviews, 41: 4218-4244, (2012). [19] Peyghambarzadeh S.M., Shahpouri S., Aslanzadeh N., Rahimnejad M., “Thermal performance of different working fluids in a dual diameter circular heat pipe”, Ain Shams Engineering Journal, 4: 855-861, (2013).