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

Integrating thermal storage with phase change materials (PCMs) in refrigeration and air conditioning processes enables energy performance improvements. Herein, the experimental phase diagram of the alkane system dodecane-tridecane (C12H26-C13H28) is evaluated to find PCMs for freezing applications. For that, the temperature-history method was coupled with a Tammann plot analysis. The obtained C12H26-C13H28 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% C13H28 compositions. The 17.7 mol% C13H28 is the narrowest minimum-melting composition among those analyzed, melting and freezing between −16 and −12 °C and between −17 and −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.