SU1733461A1 - Store-heating phase-transient material - Google Patents

Abstract

The invention relates to a power system, in particular, to the development of heat-accumulating phase transition materials used as a working medium in heat accumulators. The purpose of the invention is to reduce the level of the operating temperature and increase the energy intensity of the heat-accumulating material by increasing the specific heat of the phase transition. The heat-accumulating phase transition material contains, wt%: sodium nitrite 39.7-41.4; potassium nitrate 50.5-52.7; sodium acetate 5.9-9 8 and melt at 124-130 ° C with a specific heat of phase transition 126-132 kJ / kg. The use of the developed phase transition material allows the accumulation in the volume of 1 m of thermal energy in the amount of 245-256 MJ. The scope of the invention is heat storage power plants. 1 tabl (L

Description

The invention relates to a power system, in particular to the development of heat-accumulating phase transition materials used as a working medium in heat accumulators,

The closest in technical essence to the present invention is a phase transition material containing, as components, salts of nitrous and nitric acids, namely sodium nitrite, sodium nitrate and potassium nitrate in the following ratio, wt.%:

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the composition melts at 142 ° C with a specific heat of phase transition of 81.4 kJ / kg.

The disadvantages of the known phase transition material are relatively sodium nitrite. Sodium nitrate. Potassium nitrate.

This is a high level of operating temperature and low power consumption due to the low specific heat of the phase transition.

The aim of the invention is to reduce the operating temperature and increase the energy intensity of the heat-accumulating material by increasing the specific heat of the phase transition.

This goal is achieved by the fact that sodium acetate is additionally added to the composition containing salts of nitrous and nitric acids in the following ratio of components, wt.%

Sodium nitrite 39,7-41,4

Potassium Nitrate 50.5-52.7

Sodium acetate 5.9-9.8

The proposed heat storage material melts at 124-130 ° C with a specific heat of phase transition of 126-132 kJ / kg

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The known phase transition material cannot be used to store heat below 142 ° C. since at this temperature a liquid-solid phase transition takes place, on the basis of which thermal energy is stored and released. The use of a known material for the accumulation of heat of lower potential involves the search for effective additives that lower the temperature of the phase transition, but without compromising the basic technological properties of the heat-accumulating material — the heat of phase transition. Such an additive in this technical solution is sodium acetate, which makes it possible to lower the level of the working temperature of the heat-accumulating material by 12-18 ° C, while significantly increasing the specific heat of the phase transition.

In order to obtain the proposed phase transition material, ingredients that contain 6-10 mol% (5.9-9.8 mol%) sodium acetate are optimal (see table).

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It follows from the table that the proposed phase transition material has a lower melting point and high values of the specific heat of the phase transition, which provides a significant deterioration in the characteristics of the heat accumulator: the operating temperature decreases to 124-130 ° C and the energy intensity increases to 245-256 MJ / m3.

Claims (1)

Invention Formula Heat-accumulating phase transition material based on sodium nitrite and potassium nitrate, characterized in that, in order to reduce the operating temperature and increase energy intensity by increasing the specific heat of the phase transition, it additionally contains sodium acetate in the following ratio of components, wt.%: Sodium nitrite 39,7-41,4 Potassium Nitrate 50.5-52.7 Sodium acetate 5.9-9.8