Experimental phase diagram of the dodecane–tridecane system as phase change material in cold storage

Abstract

Highlights: C12H26-C13H28 system has a congruent minimum-melting solid solution and polymorphs  The minimum-freezing 17.7 mol% C13H28 blend (at -16 to -12 °C ) is a potential PCM  17.7 mol% C13H28 blend freezes with an enthalpy of 165 kJ kg -1 and no supercooling  The system has a minimum-melting trend, but has no eutectic as literature proposed  Extensive physicochemical studies needed to explain melting/freezing discrepancies AbstractIntegrating thermal storage with phase change materials (PCMs) in refrigeration and air conditioning processes enables energy performance improvements. Herein, the experimental phase diagram of the alkanes system dodecane-tridecane (C 12 H 26 -C 13 H 28 ) is evaluated to find PCMs for freezing applications. For that, the Temperature-history method was coupled with a Tammann plot analysis. The obtained C 12 H 26 -C 13 H 28 phase diagram indicated a congruent minimum-melting solid solution and polymorphs. The minimum-melting liquidus and the polymorphs identified here, agree with previous literature. However, the system does not represent a eutectic, as previously was proposed. The minimum-melting composition is here identified within 15-20 mol% C 13 H 28 compositions. The 17.7 mol% C 13 H 28 is the narrowest minimum-melting composition among those analyzed, melting and freezing between -16 to -12 °C and -17 to -15 °C, with: the enthalpies 185 kJ kg -1 and 165 kJ kg -1 ; no supercooling; and only minor hysteresis. Hence, this blend has potential as a PCM in freezing refrigeration applications.

Effect of phase separation and supercooling on the storage capacity in a commercial latent heat thermal energy storage: Experimental cycling of a salt hydrate PCM

“…This effect can be prevented if the initial composition of the PCM is adjusted to circumvent the region of incongruent melting [14,15]. Phase diagrams are in this case very useful [16]. Incongruent melting is observable already on material scale, since it is an intrinsic problem due to a unstable material composition.…”

n-Alkanes Phase Change Materials and Their Microencapsulation for Thermal Energy Storage: A Critical Review

“…Yilmaz et al 64 presented the liquidus line of C 12 -C 13 and found a maximum melting point of -3.3°C at 80% C 13 , whereas Ventolà et al 29 identified a eutectic composition in this system. Most recently, Gunasekara et al 40,[42][43] carried out an overall experimental investigation of C 12 -C 13 , The obtained phase diagram indicated a congruent minimum-melting solid solution and polymorphs phases at lower temperatures. However, the system does not represent a eutectic, which is against to phase diagrams proposed by the Yilmaz et al 64 and Ventolà et al 29 .…”

“…However, some of the C n blends were still missing. Therefore, based on their work, Table summarized more comprehensive binary C n mixtures (C 8 –C 50 ) by listing the PCM-interesting characteristics, and the temperature range is from 211.7 to 359.1 K (−61.5 to 86.0 °C). − ,− The compositions are either weight, molar, or volumetric percentage, while the enthalpies are either kJ/kg or kJ/mol.…”

Development of polymeric insulating foams for low‐temperature thermal energy storage applications

“…[6][7][8][9][10] Several materials are commonly used, among which the most used are expanded polystyrene (EPS), extruded polystyrene (XPS) and polyurethane foam. 11,12 Rigid polyurethane foam (PUF), together with EPS, is nowadays one of the most widely used thermal insulation material, 4,13,14 as it exhibits low thermal conductivity (λ between 0.022 and 0.040 W/mÁK), coupled with lightness (40-120 kg/cm 3 ) and cheapness (close to 3.40 €/kg). [15][16][17][18][19] In the refrigeration sector, PUF is typically sprayed between the inner and outer envelope of freezers free to expand, but it can also be produced as panels for other use like in buildings.…”