CS209582B1 - Heat transfer medium - Google Patents

Abstract

Heat transfer medium for the useful transfer of heat between two environments of different temperature by means of a liquid carrier of heat or cold. The invention addresses the technical problem of using a hitherto unused non-toxic liquid as a carrier of heat or cold. The essence of the invention; a heat transfer medium containing 10 to 70 parts by weight of an aminocarboxylic acid selected from the group comprising iminodioic acid, nitrilotriotic acid, ethylendylaminetetraacetic acid, 1,2-diaminocyclohexane-B,B,B',B '-tetraacetic acid and bia-2-aminoethyl ether-N,B,B',N '-tetraacetic acid, their salts and derivatives either alone or in a mixture, and 90 to 30 parts by weight of water.

Description

(54) Heat transfer medium

Heat transfer medium for the useful transfer of heat between two environments of different temperature by means of a liquid carrier of heat or cold. The invention addresses the technical problem of using a hitherto unused non-toxic liquid as a carrier of heat or cold. The essence of the invention; a heat transfer medium containing 10 to 70 parts by weight of an aminocarboxylic acid selected from the group comprising iminodioic acid, nitrilotriotic acid, ethylendlaiatetraotic acid, 1,2-diaminocyclohexane-B, B, B', B '-tetraotic acid and bia-2-aminoethyl ether-N, B, B', N '-tetraotic acid, their salts and derivatives either alone or in a mixture, and 90 to 30 parts by weight of water.

209,582

The invention relates to a heat-carrying medium, i.e. a liquid carrier of heat or matter.

According to the established requirements of world technology, heat transfer fluids must have physical properties of certain parameters in order to be able to perform their function well. In particular, they must be perfectly soluble in water, have low viscosity, good thermal conductivity, high specific heat, higher boiling point, lower melting point and perfect surface wetting. In the event that the heat transfer fluid solidifies at low temperatures, it must form only individual fine crystals and, when diluted with water, must exhibit softening effects; in addition, it must be able to dissolve scale deposits and metal oxide products. Above all, however, the heat transfer fluid must not be toxic and the raw materials for its preparation must be readily available.

With regard to the aforementioned requirements, numerous substances were tested which, due to their physical properties, but especially their viscosity and density, seemed suitable for fulfilling the aforementioned tasks and conditions.

Heat transfer substances, which are known in the current world technology and which are used for useful heat transfer, however, often have a strong corrosive effect and therefore an inhibitor must be added to them; however, this is often problematic due to its toxicity. For example, heat transfer substances based on polyhydric alcohols, their polymers and derivatives such as glycol and its derivatives are known; the disadvantage of their physical properties is primarily a significant viscosity, low specific heat, low to very low thermal conductivity, which impairs heat transfer. Their other disadvantages are toxicity and lack of useful raw materials. Thermal diamide, such as N,N'-dimethyl-N,n'-dihexylazelamide, whose use as an organic heat transfer medium was reported in US Pat. No. 3,910,847 - 1974, is not universally applicable either.

In comparison with the above-mentioned substances, substances belonging to the extensive group of aminocarboxylic acids, in which several carboxyalkyl groups are bound to the nitrogen atom, have proven to be more advantageous heat transfer media. At present, some of them are used for the treatment of fabrics intended for rubberization, especially for the removal of so-called rubber poisons such as residues of iron, copper and manganese, for the treatment of water during bleaching with hydrogen peroxide, for dyeing with those dyes free of metals that aminocarboxylic acids bind. These substances are also used in optical brightening and other refining processes such as washing and meroerization, and generally in the treatment of white or light-colored goods, where there is a risk of yellowing or staining due to the influence of iron (Chema zpravod 1971/1). Other of the mentioned substances find their application in the leather and paper industries, further in the chemical sector as a component of stabilizing baths in color photography and in industrial production as an auxiliary agent for alkaline cleaning of boilers and for breaking down scale and scale and also for softening feedwater for low-pressure and medium-pressure boilers, etc. (Chema zpravod (1970) 1), for example ethylenediaminetetraacetic acid and others. They are an important reagent in analytical chemistry to a considerable extent (Přibil fi.: Complexes in Chemical Analysis NCSAV Prague (1957) 43).

The use of the aforementioned substances as heat transfer media has not been considered or described until now.

Further tests revealed that these substances, which have a relatively low viscosity (at 0° 2.2 to 3.7 lo ⁶ .m ² .8eo ^-3 ·; at 50® C 1.3 to 1.6. 10” ⁶ .m ² .see“ ¹ ) 1 density (at 23° C 1.058 to 1.147 g.om“ ³ ), can be advantageously used as heat transfer media (heat or cooling media) for the useful transfer of heat to be introduced into or removed from a certain environment.

The above-mentioned disadvantages of known media are eliminated by the thermal medium according to the invention, the essence of which is that it consists of 10 to 70 parts by weight of an aminocarboxylic acid selected from the group consisting of aminodioic acid, nitrilotriolic acid, ethylenediaminetetraacetic acid, 1,2-diaminocyclohexane-H,R,N^Ny-tetraacetic acid and bis-2-aminoethyl ether-N,N,N',N',-tetraacetic acid, their salts or derivatives alone or in a mixture, and 90 to 30% by weight of water.

Compared to previously known heat transfer media, such as glycol-based agents, for example 1,2-propylene glycol, the advantage of the heat transfer media according to the invention is the significantly lower average viscosity values, especially in the temperature range of 0 to 40° C.

The advantages of this solution are apparent from the following exemplary embodiment, which clarifies the essence of the invention without limiting it in any way.

Example

The heat transfer agent is sodium sd& N,M-bls-beta-hydroxyethylglyol, which is diluted with water to a 30% by weight solution when used. It has the following physical properties:

I. Viscosity. (10” ⁶ .m ² .so.e” ¹ )

0 10 Temperature 20 In °G 30 40 50 sample control 8.3 5.1 2.5 3.6 2.3 1.9 1.4

2. Density (g/cm²) sample 1.14697

3. Specific expansion in volume % (cooled from 24° C to 0® C) sample not measured

4. Freezing point in °C sample - 15 control - 15

5. Expansion during solidification in vol. % sample 2.7

J

6. Heat capacity of liquids in (average value in the range from 0 to 40 °C) sample 3687.15

Note:

+) control sample of the previously used heat exchange material based on 1,2-propylene glycol

Claims (1)

pSedmStvtmalszu The epoxy-carrying medium is characterized in that it comprises 10 to 70 parts by weight. Amino-carboxylic acids selected from the group include iminodioic acid, nitrillotriootic acid, ethylenediamizetetraootic acid, 1,2-diamine-cyclohexane-N, N, N ', N'-tetraootic acid and bls-2-aminoethylethsr-K, M, H', K ^, -tetraootic acid. %, its salts and derivatives, either alone or in admixture, and 90 to 30 parts by weight of the composition. of the Vedas.