Thermo-physical characterization of some paraffins used as phase change materials for thermal energy storage
- 684 Downloads
Three phase change paraffinic materials (PCMs) were thermophysically (phase-transition temperatures, latent heat, heat capacity at constant pressure, density, and thermal conductivity) investigated in order to be used as latent heat storage media in a pilot plant developed in Plovdiv Bulgaria. Raman structural investigation probes aliphatic character of the E53 sample, while the E46 and ECP samples contain also unsaturated components due to their Raman features within 1,500–1,700 cm−1 range. Orthorhombic structure of the three PCMs was evidenced by the Raman modes at the 1,417 cm−1. The highest latent heat value, ΔH, of phase transitions among the three materials was represented by summation of a solid order–disorder, and melting latent heat was encountered by the E53 paraffin, i.e., 194.32 J g−1 during a μ-DSC scan of 1 °C min−1. Conversely, the ECP composite containing ceresin component shows the lowest latent heat value of 143.89 J g−1 and the highest thermal conductivity of 0.46 W m−1 K−1 among the three phase change materials (PCMs). More facile melt-disordered solid transition with the activation energy of 525.45 kJ mol−1 than the lower temperature transition of disorder–order (E a of 631.73 kJ mol−1) during the two-step process of solidification for the E53 melt are discussed in terms of structural and molecular motion changes.
KeywordsLatent heat storage Phase change material Raman spectroscopy DSC Paraffin Composite
Partially support of the EU (ERDF) and Romanian Government that allowed for acquisition of the research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM - Nr. 19/01.03.2009, and Bulgarian research project 102ni063-24/05.05.2010 of the Technical University of Sofia, is gratefully acknowledged. Results were presented in frame of COST Action TU0802 NeCoE-PCM.
- 17.Fernandez AI, Sole A, Barreneche C, Martinez M, Martonell I, Miro L, Hadjeva M, Boudenne A, Bey Sana S, Magali F, Constantinescu M, Anghel EM, Malikova M, Krupa I, Penelosa C, Delgado M, Lazaro A, Paksoy HO, Yilmaz B, Bajare D, Sumiga B, Boh B, Haussmann T, Stefan S, Weber R, Fumarski P, Jarowski M, Cabeza LF. Characterization of PCM conventional and non-conventional technologies, Proceedings of the 2nd International Energy Storage Conference, Trinity College Dublin. 19–21 June 2013. pp. 85–91.Google Scholar
- 19.Mehling H, Cabeza LF. Heat and cold storage with PCM. Heat and Mass Transfer. Berlin Heidelberg: Springer Verlag; 2008.Google Scholar
- 20.Popov R, Georgiev A, SCADA system for study of the installation with solar collectors, charging phase change materials and borehole storage, Proceedings of the 2th International Energy Storage Conference, Trinity College Dublin. 19–21 June 2013. pp. 206–212.Google Scholar
- 21.Georgiev A, Tabakova S, Popov R, Valkov I, Moev S, Barzilova S, Lishev S, Takev M, Vassilev A, Boichev A. Construction and modeling of heat energy storage with phase change materials. J Technic Univ Sofia, branch Plovdiv. 2011;16(2):45–51.Google Scholar
- 24.Wagner W, Kleinrahm R, Losch HW, Watson JTR. Hydrostatic Balance Densimeter with Magnetic Suspension. In: Goodwin A, Marsh KN, editors. Measurement of the “Measurement of the Thermodynamic Properties of Single Phases”, Elsevier, 2003. Amsterdam: Elsevier; 2003. p. 125–219.Google Scholar
- 32.Zuckerman JL, Pushaw RJ, Perry BT, Wyner DM. Fabric coating containing energy absorbing phase change material and method of manufacturing same. US Pat. 2003;6660667:B2.Google Scholar