Transient Behavior Analysis for Solar Energy Storage in PCM-CFM Material Using Equivalent Heat Capacity Method as Storage Model
A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
H. Kotani, S. D. Sharma, Y. Kaneko, T. Yamanaka, and K. Sagara," Development of Solar Chimney with Built-In Latent Heat Storage Material for Natural Ventilation", Department of Architectural Engineering, Graduate School of Engineering, Osaka University 2-1, Yamadaoka, (2005), pp. 565-0871, Suita Osaka, Japan.
Mustafa B. Al-Hadithi "Use of Phase Change Material in Residential Walls to Reduce Cooling Load", AJES, Vol.4, No.1, (2011), pp.72-86.
Alkilani Mahmud, Sopian K., Alghoul M. A., and Mat Sohif, "Using a Paraffin Wax-Aluminum Compound as a Thermal Storage Material in a Solar Air Heater", ARPN Journal of Engineering and Applied Sciences, Vol. 4, No. 10, December, (2009), pp.74-77.
M. E. Poulad, and Alan Fung, "Potential benefits from Thermosyphon- PCM (TP) integrated design for buildings applications in Toronto", Proceedings of eSim 2012: The Canadian Conference on Building Simulation.
Karima E. Amori and SaifWatheq Mohammed, "Experimental and numerical studies of solar chimney for natural ventilation in Iraq", Energy and Buildings 47, (2012), pp.450-457.
Pathik H. Vadwala, "Thermal Energy Storage in Copper Foams filled with Paraffin Wax", M.ScThesis, Mechanical & Industrial Engineering, University of Toronto, 2011.
K. Boomsma and D. Poulikakos, "On the effective thermal conductivity of a three-dimensionally structured fluid-saturated metal foam", International Journal of Heat and Mass Transfer 44 (2001), pp. 827-836.
Yuan Tian, "Heat Transfer Enhancement in Phase Change Materials (PCMs) by MetalFoams and Cascaded Thermal Energy Storage", PhD, Thesis, University of Warwick. 2012.
Y. Tian and C.Y. Zhao, "Thermal and Exergetic Analysis of Metal Foam-enhanced Cascaded Thermal Energy Storage (MF-CTES)", International Journal of Heat and Mass Transfer 58, (2013), pp. 86–96.
Anil W. Date,” Introduction to Computational Fluid Dynamics”, Indian Institute of Technology, Bombay, Cambridge University, Press 2005.
Kau-Fui Vincent Wong, "Intermediate Heat Transfer", University of Miami Coral Gables, Florida, U.S.A., Marcel Dekker, Inc., 2003.
"3-D Heat transfer problem", Texas advanced computer center, the University of Texas at Austin.
Mahesh Prakash,Özden F. Turan, and Graham R. Thorpe. "Program NATCON: For the numerical of Buoyancy-driven laminar and turbulent flows in differentially heated cavities", a new school of thought, Victoria University, Melbourne Australia, 2006.
Sajda, F. S., "Simulation of trombe wall in mixed convection plus conduction", MS.C, thesis, University of Technology, Technical Education Dep., 2005.
Ahmed K. Taha, "Simulation of Heat Storage and Heat Regeneration in Phase Change Material", MSc thesis, University of Baghdad, 2010.
Copyright: Open Access authors retain the copyrights of their papers, and all open access articles are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided that the original work is properly cited. The use of general descriptive names, trade names, trademarks, and so forth in this publication, even if not specifically identified, does not imply that these names are not protected by the relevant laws and regulations. While the advice and information in this journal are believed to be true and accurate on the date of its going to press, neither the authors, the editors, nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.