UNIV. NEWS. NORTH-CAUCAS. REG. TECHNICAL SCIENCES SERIES. 2021; 1: 85-90
http://dx.doi.org/10.17213/0321-2653-2021-1-85-90
VARIABILITY OF THE VALUES OF THE ENTHALPY OF MELTING OF ICE AND ICE-CONTAINING MIXTURES
Iskenderov Eldar G. – Candidate of Chemical Science, Senior Researcher, Institute of Problems of Geothermy and Renewable Energy (branch) Joint Institute for High Temperatures of the RAS, Makhachkala, Dagestan, Russia. E-mail: elisk13@mail.ru
Abstract
When studying the compositions for cold accumulators, one of the main characteristics, along with the melting time, is the melting enthalpy of the substance that is part of the accumulator. In modern studies of the values of the specific heats of melting of ice and ice-containing mixtures during the isobaric process, the result is the average value obtained as a result of a series of experiments. At the moment, there is no justification for the fact that the values of the heats of fusion, in these series of experiments, can differ by up to 45 KJ / kg. In this case, the difference between the values of the initial and final phases, on which the obtained result depends, changes with each measurement, which may depend on the anomalous properties of the water present in the sample for the cold accumulator, the influence of polymorphism of melt water clusters, the randomness of the hydrogen bond network, and the effect of proton disorder. The lack of repetitiveness both in one series of the experiment and in all series and the impossibility of obtaining an accurate value complicates the study of the compositions for the cold accumulator. In this work, on the basis of a large amount of data obtained, an attempt is made to explain the possibility of a scatter in the values of the enthalpy of melting of ice and ice-containing mixtures.
Keywords: enthalpy of fusion; specific heat of fusion; cold accumulator; calorimeter; aqueous solutions of salts and acids; temperature measurement; phase transition.
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