| Abstrakt: |
Using thermal analysis methods (DTA, VPA, and partly RFA), a melting diagram for a quaternary reciprocal system of potassium and calcium fluorides, chlorides, and tungstates was constructed. The system consists of 11 crystallization volumes, six of which belong to the initial components, four to compounds and a solid solution of tungstates K2WO4·CaWO4. The curves of three-phase monovariant equilibria converge at eight quadruple invariant points: five eutectic and three transitional. Five eutectics of the system are recommended as a heat-storage material (TAM) in heat accumulators (TA) of a phase-transition type, utilizing heat from braking resistors of electrodynamic resistance (EDS) and exhausts of hot gases of internal combustion engines. To establish the operating temperature range in TA, it is advisable to add an additional 5-8 wt. % technical wax with a melting point of 72.6 - 87.2 °C and a specific heat of phase transition of 146-147 kJ/kg. [ABSTRACT FROM AUTHOR] |
