Influence of Additive NaCI on the Phase-Change Heat Transfer and Storage Capacity of NaNO3-KNO3 Mixture
OPEN ACCESS
Efficient absorption and storage of heat is indis are decmed as one of the most suitable materials for high-temperature heat storage. In this paper eutectic $\mathrm{NaNO}_{3}-\mathrm{KNO}_{3}$ mixed salts were prepared as base material, and NaCl was used as additives to lower the salt mixtures' melting temperatures and consequently to extend their use temperature ranges. Major thermal properties of the mixtures are characterized using Thermogravimetric Analyzer (TGA) and Differential Scanning Calorimetry (DSC). Here we find that the smelting temperatures of the salt mixtures are approximately $10^{\circ} \mathrm{C}$ lower than that of the pure solar salt. The addition of a limited amount of $\mathrm{NaCl}$ causes no significant deterioration to the latent heats. The decomposition temperatures basically decrease with the amount of $\mathrm{NaCl}$ added at identical weight losses. In the temperature interval $280-380^{\circ} \mathrm{C}$ the specific heat capacities decrease gradually with the temperature. It reveals that the NaCl additive plays a positive role in improving the thermal properties of the NaNO, $\mathrm{KNO}_{3}$ mixtures for phase-change heat transfer and storage.
thermal energy storage, latent heat, phase-change heat transfer, $\mathrm{NaNO}_{3}-\mathrm{KNO}_{3}$ mixture, NaCl additive
[1] A. Medjelled, A. Benchatti, et al, Experimental model for the study of heat transfer in unsaturated soil: Case of underground thermal storage, International Journal of Heat and Technology, vol. 26, pp. 95-102, 2008.
[2] M. Thirugnanasambandam, S. Iniyan, et al, A review of solar thermal technologies, Renewable and Sustainable Energy Reviews, vol. 14, pp. 312-322, 2010.
[3] K. H. Solangi, M. R. Islam, et al. A review on global solar energy policy, Renewable and Sustainable Energy Reviews, vol. 15, pp. 2149-2163, 2011.
[4] M. Conte, A. lacobazzi, et al, Hydrogen economy for a sustainable development: state-of-the-art and technological perspectives, Journal of Power Sources, vol. 100, pp. 171-187 ,2001.
[5] U. Herrmann and D. W. Kearney, Survey of thermal energy storage for parabolic trough power plants, Journal of Solar Energy Engineering, vol. 124, pp. 145-152, 2002.
[6] H. Michels and R. Pitz-Paal, Cascaded latent heat storage for parabolic trough solar power plants, Solar Energy, vol. 81, pp. 829-837, 2007.
[7] A. Hoshi, D. R. Mills, et al, Screening of high melting point phase change materials (PCM) in solar thermal concentrating technology based on CLFR, Solar Energy, vol. 79, pp. 332-339, 2005.
[8] A. F. Regin, S. C. Solanki, et al, Heat transfer characteristics of thermal energy storage system using PCM capsules: A review, Renewable and Sustainable Energy Reviews, vol. 12, pp. 2438-2458, 2008.
[9] C.Y. Zhao and Z.G. Wu, Thermal property characterization of a low melting-temperature ternary nitrate salt mixture for thermal energy storage systems, Solar Energy Materials and Solar Cells, vol. 95, pp. 3341-3346, 2011.
[10] M. Faraji and H. EI Qarnia, Numerical optimization of a thermal performance of a phase change material based heat sink, International Journal of Heat and Technology, vol. 26, pp. 17-24, 2008.
[11] M.M. Kenisarin, High-temperature phase change materials for thermal energy storage, Renewable and Sustainable Energy Reviews, vol. 14, pp. 955-970, 2010.
[12] B. Zalba, J. M. Marin, et al, Review on thermal energy storage with phase change: materials, heat transfer analysis and applications, Applied Thermal Engineering, vol. 23, pp. 251-283, 2003.
[13] A. F. Khadrawi and M. A. Al-Nimr, A simplistic way for cooling an intermittent operating internal combustion engine, International Journal of Heat and Technology, vol. 26, pp. 175-178, 2008.
[14] M. M. Farid, A. M. Khudhair,et al, A review on phase change energy storage: materials and applications, Energy Conversion and Management, vol. 45, pp. 1597-1615, 2004.
[15] U. Herrmann, B. Kelly, et al, Two-tank molten salt storage for parabolic trough solar power plants, Energy, vol. 29, pp. 883-893, 2004.
[16] H. Price, E. Lüpfert, et al. Advances in parabolic trough solar power technology, Journal of solar energy engineering, vol. 124, pp. 109-125, 2002.
[17] D. Kearney, U. Herrmann, et al, Assessment of a molten salt heat transfer fluid in a parabolic trough solar field, ASME Journal of Solar Energy Engineering, vol. 125, pp: 170-176, 2003.
[18] D. Kearney, B. Kelly, et al, Engineering aspects of a molten salt heat transfer fluid in a trough solar field, Energy, vol. 29, pp. 861-870, 2004.
[19] Q. Peng, J. Ding, et al, The preparation and properties of multi-component molten salts, Applied Energy, vol. 87, pp. 2812-2817, 2010.