HU204299B - Latent heat receiver - Google Patents

Abstract

The invention relates to a latent heat storage with non-corrosive melting substances with large heat input and -ausspeicherleistungen and without thermal stresses. These reservoirs are effective systems for relieving or supplementing conventional power generation systems and for balancing temporal fluctuations between energy consumption and energy demand. They are preferably designed for adapting heat recovery systems to heat utilization conditions. According to the invention, an active storage filling consisting of 4 material systems is proposed. Material system I consists of one or more substances with heat-storing properties, which have no decomposition phenomena during melting. Fabric system II is formed by a heat transfer medium, which is unable or only partially to dissolve the material system I. Surface-active substances include the substance system III, while substance system IV consists of one or more nucleating agents.

Description

BACKGROUND OF THE INVENTION The present invention relates to a latent heat accumulator having an active storage charge in a container, consisting of non-decomposable materials. Latent heat storage systems are powerful devices for relieving or supplementing conventional power generation systems and for balancing power generation and energy demand over time. The latent heat storage device according to the invention can therefore be used mainly to adapt the heat consumption systems to the heat consumption conditions defined by the energy sources, i.e. to compensate the heat production and heat consumption and to store the heat.

Conventional heat storage units operate on the principle of perceptible heat. Because of the use of heat storage materials such as water, oil, stone, cast iron, etc. heat storage capacity is relatively low, the use of such heat storage facilities, especially when storing large amounts of heat, creates too much storage capacity and uneconomical investment and operating conditions. (See eg Polinszky:, Technical Lexicon, Vol. H, Academy Publisher, Budapest, 1972, 306). From a practical point of view, traditional heat storage systems have the following shortcomings:

- Filling and emptying the storage tank will cause the storage temperature to rise or fall, which in practical experience has the disadvantageous "sliding" of the storage temperature when filling or emptying the storage tank, which adversely affects heat transfer performance and costly control;

They have a relatively low specific heat capacity and thus have a very unfavorable weight / power ratio compared to the latent heat storage devices described below;

- Storage of large quantities of heat requires too much storage volume, which is often not or only very expensive and can be realized at a reasonable cost;

- In order to reduce the storage volume to a technically acceptable level, large temperature differences between the filling and discharge state should be allowed, taking into account that the filling temperature - undesirably - is higher than the prescribed and permitted temperature of the heat consuming system; its energy quality decreases;

- The most commonly used storage material, the storage of large amounts of energy when using water, is particularly problematic when it is within the required storage temperature of the water at the inside temperature limit (90 ° C for unpressurised system or 90/70 ° C for heating systems). Increasing storage capacity by increasing the water temperature without pressure would be impossible and unacceptably high.

These shortcomings would be overcome by heat storage devices that operate on the principle of latent heat rather than sensible heat. Examples of such latent heat include melting, evaporation, condensation, reaction, hydration, dissolution, and crystallization heat. These types of heat storage tanks are referred to in the literature as "4-way heat storage".

Latent heat storage tanks have the following advantages over conventional heat storage tanks:

- During loading and unloading, the storage temperature remains substantially constant over a limited range of heat uptake and heat release;

The heat transfer capacities are also constant, depending on the technical solution 10, over a relatively small range;

- Their heat absorption capacity is 2-40 times higher than conventional heat storage tanks, depending on the temperature range of the storage medium used and the heat absorption or heat transfer.

Among the low-temperature storage units, they are mainly distinguished by their favorable properties for melting and solidification heat.

A number of such types of transient heat storage units are known which substantially eliminate the physico-chemical problems of the fusible materials. Examples of such solutions are 2648 678,1928 694,

No. 523,234,2,517,921. U.S. Patent No. 154,125; and U.S. Patent Nos. 2,443,619; GDR Patent 25252995. Improvements in these were mainly aimed at exploring the material of the storage materials and eliminating freezing or layering. A latent heat reservoir is known from British Patent No. 4,400, in which Id30 is used exclusively as a salt melt and a heat transfer medium is a liquid. Auxiliary pumps and coolers are used for phase conversion operations, ie the unit is not closed. The turbulent flow of material is achieved by additional stirrers.

In addition, U.S. Pat. Nos. 4,272,392 and 4,329,242. U.S. Patent Nos. 2,093,347; látenshőtárolók according to British Patent lefrás tárolótöltete exclusively solid / liquid phase transformation work described above, solutions, none al40 immensely however, solve the problems that dermedésekor various non szétbomolva melt such congruent and eutectic melting materials, the resulting crystals of a large volume set into _(grow amipedigmindhőfelvételkor, all the while leading to highly reduced heat transfer rates during transmission, as well as melt roughening, opacity, thermal stresses and excessive internal pressures.

It is also known in the art that the addition of fluorine-containing surfactants can reduce the size of crystals formed during the setting of the incongruent melting glaucose salt (Na ₂ SO ₄ x 10H ₂ O). For example, U.S. Patent 4,267,879 discloses this.

However, no specific proposals have been made so far to reduce the crystalline size of heat storage materials that can be used in non-decomposed (e.g., congruent) melting latents. Moreover, for congruent fusible materials (e.g., Na ₂ S x 5 H ₂ O), this has not resulted in this.

HU 204299 Β

It is an object of the present invention to provide latent heat accumulators with non-decomposable melting materials which, without the use of any additional mechanical aids, prevent the formation of large volumes, crusting and opacity, and at the same time improve heat transfer and heat transfer performance.

In order to accomplish this object, we have started from a latent heat storage tank having a container, a storage charge thereof mixed with non-decomposable materials, and heat transfer and heat transfer units arranged in the container. The essence of the present invention is that the active storage charge arranged in the closed container is in the interaction I, Π, which seeks to balance each other during phase changes. and ΙΠ. ingredients, and where appropriate

ARC. contains a component for which

- component I consists of at least one eutectic and ^J congruent melt storage medium, the proportion of which is 50-90 vol.

- a Π. ingredient azl. component insoluble refrigerant medium, the proportion of which, in the total volume of the storage charge (2), is between 3 and 50% by volume and the phase change between evaporation and condensation is as follows:

PjjPj-melt and

Pn <Pn — where "p" is for I. and Π. the density of the component and the "p" to denote their pressure - further

- component Hl contains at least one surfactant in a proportion of 0.01 to 5% by volume of the total volume of the container fill (2), and

- IV. The component contains at least one crystal nucleation component in a proportion of 0 to 20% by volume of the total volume of the storage charge (2), which is 0 if component I is not cooled.

According to a further feature of the present invention, it is expedient to have an embodiment wherein the latent heat storage container is located in a pressure-tight and insulated sealed container so as to completely surround the heat transfer unit while leaving a vapor space in the tank containing the gaseous heat transfer fluid.

As will be seen from the foregoing, in accordance with the present invention, f. Component I may be omitted if component I is not or only slightly cooled.

I to IV according to the invention. The container charge of the components has specific properties, and IIV. The components interact with each other in such a sense that automatic phase equilibrium is established during phase changes.

Component I itself is a heat storage material that absorbs or releases latent heat during melting or solidification. It is assumed that component I does not decompose upon melting, and therefore has a substantially constant density and composition. However, this property includes the tendency to form large volumes of agglomerates, clouding and peeling. This undesirable side effect, according to the invention, is counteracted by a. component.

AH. component is the heat transfer medium itself, in which:

Component I is not or only slightly soluble. The Π. The component is evaporated and condensed at a heat input in which the temperatures are above the melting point of component I or in heat extractions when the temperatures are below the solidification temperature of component I.

Due to the closed tank, the pressure values for the above temperatures are set automatically during heat transfer and heat extraction. More importantly, the components must be selected so that the pressure of component I is substantially lower than that of component Π.

Thus, according to the above relation, heat transfer and heat dissipation are essentially Π. as a function of the gas pressure of the component. Under this condition, we also determined the content of component I (solid / liquid) and Π. component (liquid / gas) state.

On the other hand, it is an essence of the invention that the density ratio should be chosen such that the density of the component I (in the melt phase) is less than that of Π. component density. This way we get to Π. evaporation and condensation of the component in specific portions of the vessel, thereby achieving relatively high heat transfer performance.

The component H1 according to the invention is a surfactant intended to reduce the interfacial tensions between the melt (component I) and the condensate (component Π). AΙΠ. The addition of a component increases the immersion depth of the condensate droplets, i.e. evaporation occurs under the crystalline layer and in its intermediate spaces. Consequently, the resulting crystals are subjected to stronger motion. This can safely prevent the crystals from "sticking together".

AIV. Component of the Invention Optionally Used in the Invention Crystal Core Additive The purpose of this is to prevent overcooling. For this, it is necessary to finely distribute the crystal nucleating additive in the melt, which is achieved by evaporation during bubble formation, and by continuous mixing of the crystal melt. This is the IV. additive may be omitted if component I is not cooled.

The advantageous effects of the latent heat storage device according to the invention are mainly due to the specific interaction of the I-DL components of the storage charge.

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings and examples, Figure 1 is a schematic sectional view of a latent heat storage device according to the invention, which is to be considered as an exemplary embodiment.

As shown in Figure 1, the latent heat accumulator of the present invention has a sealed container 1, which in this case is a pressure-rigid container which is thermally insulated. The container 1 is provided with a container filling 2 according to the invention, which consists of non-degradable materials, i.e. components

Hü 204299 Β mixed up, but for more details, we will go over the examples.

In the figure, it is clear that the enclosed interior space 1 of the container is not completely filled by the active storage container 2, but the heat transfer unit 3 in the lower part of the container 1 is surrounded by the storage container 2. Above the reservoir filling 2 is located a heat transfer unit 4 in the interior space of the tank 1 for the removal of snow, which is formed as a surrounding vapor space. In the space 5, the snow deflector unit 4 is exclusively connected to the gas non-heat transfer medium 10.

The snow transfer units 3 and 4 in this case are shaped as a tube snake known in itself, in which heat transfer (receiving or transfer) media are flowed in a manner known per se. 15

Some examples of the composition of the active container 2 according to the invention are given below:

Example 1

Ingredient-L: 70% by volume

Euthetic mixture of Mg (NO ₃ ) ₂ x ₆ H ₂ O and MgCl ₂ x ₆ H ₂ O

-Π. Component: 28% v / v Ld-bromomethane -HL Component: 1% v / v "Cordesin W"

-ARC. Ingredient: 1 vol.

AZL-I7. After mixing, the ingredients are filled into the container 1 and sealed thereafter.

The exemplary composition of the container fill 2 according to the invention is given in tabular form in the following Figures 2-14. examples

Mixing ratio (% by volume) the) b) c) . version d) e) A) Storage charge (2) Component I: Mg (NO _{3) 2} x ₂ x6H 0ésMgC3 xx ₂ 6H ₂ O eutectic mixture of Π. Component: (CH ₂ ClBr 95 50 50 50 70 (Klórbrómmetén) 3 49 25 49.9 28 HL Component: "CORDESIN-W" 1 0.1 5 0.05 1 Component 17: Activated carbon I 0.9 20 0.05 1 B) Storage charge (2) Component L: CH ₃ CONH ₃ 95 50 95 50 Π. component: CCI4 4.99 45 3 49.99 HL Component: "COPJDESIN-W" Component 17: - 0.01 5 2 0.01 C) Storage charge (2) Component L: Mg (NO ₃ ) ₂ x 6K ₂ O 95 50 75 50 Π. Component: CH ₂ Br ₂ HL Component: “FT248 4 49.99 24 45 (Fluortenzid) Component 17: - 1 0.01 1 5

According to the invention, the mode of operation of a latent heat accumulator is as follows:

The heat transfer or heat transfer takes place via the heat transfer unit 3 surrounded by the storage charge 2. The heat dissipation above can be accomplished in detail through the heat transfer unit 4 arranged in the steam space 5. The heat input and the heat dissipation are done with three phase changes as follows:

When the heat is introduced, if the temperature of the snow transmitter unit 3 is higher than the melting temperature of the component L of the storage charge 2, the component IL evaporates, i.e. becomes steam. This vapor formed meets the unmelted portions of component L of the storage charge 2, which condenses the vapors while melting themselves. Thus, the condensing heat released by the AIL component is utilized as the melting heat of the L component.

During heat extraction, when temperatures below the melting point prevail in the apparatus, the material of the IL component also evaporates, i.e. vaporizes, but in this case at a lower pressure than when applied to snow. The evaporation heat required for this is removed from the storage material (component L), which in the meantime passes from the melt to a solid phase. AH. The vapor of the component enters the vapor space 5, where the relatively cooler heat transfer unit 4 condenses and the released condensing heat is absorbed by the heat transfer unit 4, which is in principle utilized in a known manner.

In both cases, as described above, heat transfer is achieved by intense bubble formation and uniform heat absorption and heat dissipation in the storage charge 2.

It should be noted that the above process is IH according to the invention. in the absence of an ingredient, it would inevitably result in the formation, flaking and clouding of bulky agglomerates, which according to the invention was eliminated by the addition thereof. Depending on the intensity of bubble formation and the amount of HL component, only small-volume crystals are formed4

EN 204299, which, in turn, form a loose and transparent set in the storage charge 2.

A1V. The use of this component is advantageous because at higher heat dissipation it can induce crystal formation and prevent excessive cooling.

Finally, as an ingredient I of the container 2 according to the invention, which is at the same time its most important component, the following can be mentioned as an example:

-Na ₂ S ₂ O ₃ x ₅ H ₂ O;

- CH ₃ COONa x 3H ₂ O.

ΑΙΠ. "CORDESIN W" (manufactured by VEB Berlin-Chemie, Berlin) as an ingredient, is a complex compound of protein sulphonic acid and has the following main characteristics:

yellowish-brown, clear, slightly viscous liquid;

pH of 6.5-7.5.10% solution;

poorly soluble in water;

- alkali and acid resistant;

- readily biodegradable;

- has good crosslinking, dispersing and emulsifying properties.

I and Π. the density and pressure conditions of the components according to the invention determine the material selection from the beginning, since the specific physical parameters depending on the density and vapor pressure depend on the material

Claims (2)

CLAIMS 1. A latent heat reservoir having a receptacle arranged therein, mixed with a decomposition of non-decomposing materials and heat transfer and heat transfer units, characterized in that the active reservoir (2) arranged in the sealed container (1) interacts with one another during phase changes. and IH. and, where appropriate, IV. contains a component for which - the component consists of at least one eutectic or congruent melt storage medium, the proportion of which is 5090% by volume of the total storage charge (2); - component H is a heat transfer medium insoluble in component I, the proportion of which in the total volume of the storage charge (2) is between 3% and 50% by volume and the phase change between evaporation and condensation: PjjPj-melt and Pn <Pn — where "p" is for I. and Π. the density of the component and the "p" to denote their pressure - further - Dl. the ingredient comprising at least one surfactant in an amount of 0.01 to 5% by volume in the total volume of the container fill (2), and - IV. The component contains at least one crystal nucleation component in a proportion of 0 to 20 volumes in the total volume of the storage charge (2), which is 0 if component I is not cooled. Latent heat accumulator according to claim 1, characterized in that the storage charge (2) is located in the pressure-resistant and insulated container (1) so that it surrounds the heat-transferring unit (3), above which a vapor space (5) is provided. ), in which the heat dissipating snow transfer unit is located in a heat transfer relationship with the gaseous heat transfer medium