EXPERIMENTAL INVESTIGATION OF INDIVIDUAL EVACUATED TUBE HEAT PIPE SOLAR WATER HEATING SYSTEMS
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Abstract
lar water heating systems with heat pipes of three diameter groups of 16, 22 and 28.5 mm. The first and third groups had evaporator lengths of 1150, 1300 and 1550 mm. The second group had an additional length of 1800 mm. all heat pipes were of fixed condenser length of 200 mm. Ethanol at 50% fill charge ratio of the evaporator volume was used as the heat pipes working fluid. Each heat pipe condenser section was inserted in a storage tank and the evaporator section inserted into an evacuated glass tube of the Owens- Illinois type. The combined heat pipe and evacuated glass tube form an active solar collector of a unique design.
The resulting ten solar water heating systems were tested outdoors under the meteorological conditions of Baghdad, Iraq. Experiments were carried out with no load, intermittent and continuous load conditions. Some tests, at no load, were carried out with and without reflectors. The overall system efficiency was found to improve with load conditions by a maximum of 55%. The system employing an 1800 mm evaporator length and 22 mm heat pipe (HP7) showed the best performance by higher water temperatures, overall useful energy gain and efficiency at various load conditions. System performance was predicted theoretically using electrical analogy derived from an energy balance. An agreement of within 14% was obtained between theoretical and experimental values.
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Akyurt M., Development of Heat Pipes For Solar Water Heaters, J. Solar Energy, v.32, n. 5, pp. 625- 631, 1984.
Al-Joboory H.N.S., Experimental Investigation of Evacuated Tube Heat Pipe Solar Water Systems, Ph.D. Thesis, Mechanical Engineering Department, College of Engineering, University of Baghdad, Baghdad, Iraq, 2009.
Bairamov R. and Toiliev K., Heat Pipes in Solar Collectors, in Advances in Heat Pipe Technology, edited by Reay, D. A., pp.47-54, 1982.
Chun W, Kang Y. and Lee Y., An Experimental Study of the Utilization of Heat Pipes for Solar Water Heaters, Appl.Ther. Engng., v. 19, pp 807-817, 1999.
Esen M and Esen H., Experimental Investigation of a Two- Phase Closed Thermosyphon Solar Water Heater, J. Solar Energy, v.79, n. 5, pp. 459- 468, 2005.
Farber E. and Morrison C., Clear-Day Design Values of Solar Energy, ASHRAE GRP 170, Application of Solar Energy for Heating and Cooling of Buildings, ed.Jordon R. and Liu B., 1977
Hammad M., Experimental Study of the Performance of a Solar Collector Cooled By Heat Pipes, Renewable Energy, v. 6, n.1, pp. 11- 15, 1995.
Hussein H., Theoretical and Experimental Investigation of a Wickless Heat Pipe Flat Plate Solar Collector, Ph. D. thesis, Faculty of Engineering, Cairo University, Egypt,1997.
Kreider J. and Kreith F., Solar Energy Handbook, McGraw- Hill Co., 1981.Kreider J. and Kreith F., Solar Heating And Cooling Engineering, Practical Design and Economics, Hemisphere Publishing Corporation, 1975.
Mahdy M., Experimental Investigation of Low Heat Flux Heat Pipes With and Without Adiabatic Section For Solar Application, Ph. D. Thesis, Mech. Eng. Dept., College of Engineering, University of Baghdad, Baghdad, Iraq, 2005.
Nada S., El- Ghetany H., and Hussein H., Performance of a Two- Phase Closed Thermosyphon Solar Collector With a Shell and Tube Heat Exchanger, Applied Thermal Engineering, v. 24, issue 13, pp. 1959- 1968, 2004.
Ng K., Yap C. and Khor T., Outdoor Testing of Evacuated- Tube Heat Pipe Solar Collectors, J. Process and Mech. Engineering, v, 214, n. 1, pp.23- 30, 2000.
Noren W., Heat Pipe Flat Plate Collector With Temperature Regulation, Report SERIWA, No. 810/36/1, Sol. Energy, p. 32 Res. Inst., West Australia, 1981.
Ortabasi U., and Buehl W. M., An Internal Cusp Reflector For An Evacuated Tubular Heat Pipe Solar Thermal Collector, J. Solar Energy, v.25, pp. 67-78, 1980.
Praene J., Grade F., and Lucas F., Dynamic Modeling and Elements of Validation of Solar Evacuated Tube Collectors, 9th Int. IBPSA Conf., Montreal, Canada, 2005.
Radhwan M., Zaki G., and Jamil A., Refrigerant- Charged Integrated Solar Water Heater, Int. J. of Energy Research, v.14, pp. 421- 432, 1990.
Sivaraman B. and Mohan N., Experimental analysis of heat pipe solar collector with different L/ di ratio of heat pipe, J. Scientific and Industrial research, v. 64, n. 9, pp. 698- 701, 2005.
Walker A., Mahjouri F. And Stiteler R., Evacuated- Tube Heat Pipe Solar Collectors Applied to the Recirculation Loop in a Federal Building, NERL report NERL/ CP- 710- 36149, presented at the Solar 2004 Conf., Portland, Oregon, 2004.
Ward D., and Ward J., Design Considerations for Residential Solar Heating and Cooling Systems Utilizing Evacuated Tube Solar Collectors, J. Solar Energy, v.22, pp.113- 118, 1979.