JPS6152588A - Latent heat accumulator having substance melting without decomposing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of use of the invention Latent heat storage devices with substances that melt without decomposition are useful for relieving or supplementing conventional energy generation systems and for energy storage and storage. Therefore, the latent heat storage device according to the invention provides an advantageous method for adjusting the temporal fluctuations between the energy storage and the energy storage, in particular for adapting the heat consumption system to the heat utilization conditions imposed by the energy source. That is, it is planned to match the amount of heat generated and the demand for heat in time, and to accumulate heat.

Characteristics of known technical solutions Conventional heat storage devices work primarily on the basis of sensible or heat-sensitive heat.

All accumulating materials used for this purpose e.g. water, oil,
Since the heat capacity of stones, cast iron, rhomboids, etc. is very small,
The use of such storage schemes results in very large storage volumes, especially when storing large quantities of heat, leading to uneconomical overnight rates. From a practical point of view, conventional storage methods have the following serious drawbacks: Filling or discharging the storage device results in an increase or decrease in the storage temperature; , that the storage temperature and the heat transfer performance (both when filling the storage device and when discharging it from the storage device) constantly fluctuate, which is actually very disadvantageous, and increases the cost of the control technology that has to be used. Something happens.

Since the specific heat capacity of the storage material is generally low, the material/performance ratio is also very unfavorable for the latent heat storage devices described below.

Storing large amounts of heat is constrained to large storage volumes, which are often not industrially feasible or can only be realized at great expense. (
construction of additional new buildings) or the proportion of costs has a very unfavorable impact.

In order to reduce the storage volume to an industrially controllable size, a large temperature difference between the filled and empty conditions must be allowed, which may exceed the required operating temperature of the heat dissipating system. It has to be accepted that the load temperature will necessarily rise thereby and that the energy properties of the heat source (energy storage) will be destroyed.

When using water, which is the most frequently used storage material, it is especially important that the storage temperature required for industrial applications is at the upper limit of water (approximately 90°C at normal pressure), e.g.
When the temperature is 70°C, it is difficult to accumulate a large amount of 2-μg. Increasing the storage capacity by increasing the water temperature is not possible at normal pressure and would lead to technical and equipment overexpenditures that would add to an otherwise unfavorable cost proportion. make worse.

The possibility of overcoming these drawbacks is based not on sensible heat, but rather on latent heat such as heat of fusion, heat of solidification, heat of vaporization, heat of condensation, heat of reaction, heat of water utilization, heat of solution, heat of crystallization, etc. Provided by a working storage device.

This type of storage device is referred to in the literature as a "latent heat storage device".

This storage device has the following disadvantages compared to conventional storage devices: The storage temperature, both when filling and when emptying, always remains constant within a narrow range during heat absorption or heat release.

The heat transfer performance always remains constant within narrow limits, depending on the technical solution in each case.

Compared to conventional storage devices, the heat absorption capacity is between 2 and 40 times greater, depending on the storage material used and the width of the overall temperature range in which heat absorption and heat release occur.

A very obvious improvement device is especially the heat of fusion and solidification ′
It is a latent heat storage device that works based on heat. A number of solutions exist for such storage devices, which primarily eliminate the known thermophysical and physicochemical problems caused by fusible materials. German Patent No. 2.64
&678, German Democratic Republic Patent No. 154.125
German Patent Application No. 1.928.694, German Patent Application No. 2,523,234,
German Patent Application Publication No. 2.517.920 and German Patent Application Publication No. i2,517,921 and German Democratic Republic Patent Application Wp C09/2436
No. 19 is a part of this, and these disclose improvements in matters such as separation of materials for storage materials, over-aging, and prevention of layer formation.

The following problems have not yet been solved: The tendency of crystals that occur during the solidification of various materials that melt without decomposition, e.g. coincident melting and eutectic melting, to join together and form large agglomerates; results in significantly reduced heat transfer performance, both during heat import and heat export, resulting in fish skin,
It becomes impermeable to the melt and thermal stresses can develop and build up pressure inside the storage device.

In addition, from the literature, it has been found that Glaraber salt (Na25O
It is known that the size of crystals generated during solidification of 4.10H20) can be reduced. There is US Pat. No. 4,267,879 and corresponding patents.

On the other hand, no specific solution is known to reduce the crystal size of potential accumulation materials that melt without decomposition (e.g., congruency). Coincidentally melting materials such as Na2S/5H
, I diverted it to O, but no results were achieved.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a decomposable material which, without the use of mechanical means, prevents the formation of large amounts of agglomerates, skins and impermeability, while at the same time allowing a large heat import and heat extraction performance. The objective is to develop a latent heat storage device with a substance that melts without melting.

DETAILED DESCRIPTION OF THE INVENTION Latent heat storage devices having materials that melt without decomposition, such as materials that undergo concordant melting and eutectic melting, tend to form crystals upon solidification, which intersect and form mass agglomerates. Become. This agglomeration causes poor heat import and heat export performance and thermal stress inside the storage device. In the present invention, this drawback is obviated by the storage fill consisting of four substances.

Material system I consists of one or more substances, which exhibit heat storage properties based on the heat of fusion (or generally heat of transition) of the substance and the specific heat capacity of the substance, which melt without decomposition, and which Can be used as storage material.

According to the invention, the proportion of material thread I to the total amount of active storage fill amounts to between 50 and 95 volumes.

The material system ■ is composed of a liquid heating medium composed of one or several components, in which said material system ■ is not soluble or is only conditionally soluble.Furthermore, the material system The density of H (ρ■) and the density of the molten phase of material system I (
In the present invention, ρN) satisfies the following condition: ρ■≦ρ■, for example, 0,8ρ1, and in this case, the vapor pressure (pH) of material system (2) and the vapor pressure of material system II (CPDII) satisfy the following condition: PDI << PDII satisfies the condition. The proportion of substance system II is between 5 and 50 vol relative to the total volume of the active storage filling of the storage device.
%become.

material thread■ Consists of one or several surface-active substances.

The proportion of the material system 1 to the total volume of the active storage filling of the latent heat storage device amounts to Q, 01 to 5 vol.

Substance system (I) has the task of not crystallizing during solidification of substance system I and preventing bonding and/or skin formation.

Material system (1) Consisting of one or several types of nucleating agent, the nucleating agent causes a nucleation phenomenon or causes non-uniform nucleation due to its lattice structure.

In the present invention, the activity of the latent heat accumulating device is such that the ratio of the material system (1) to the total volume of the bond filling is 1 to 20 vol.

If material system I is not supercooled or is only slightly supercooled, the proportion of material system I to the active storage filling disappears.

EXAMPLE A latent heat storage device according to the invention is explained in detail with reference to the drawing (FIG. 1) with respect to the active storage filling of the device: Material system I: Mg (NO2 2 . 6H, +O and MgC62・
H20 Material system II: 28 vol1% chlorbromomethane CM2C! Br Material system m: 1 vol. 1% Cordesin W Material system IV: 1 vol. activated carbon These four material systems are placed in an airtight thermally insulating container 1 with an active storage fill 2
It is packed in the form of a mixture.

A heat transfer device 5 is arranged inside the container 1 in such a way that the heat transfer device 3 is completely covered by the storage filling 2 mentioned above. Another heat transfer device 4 is material system II.
The heat transfer device 4 is surrounded in the cavity 5 only by the steam of the steam.

The supply of heat takes place by the heat transfer device 5, which is surrounded by the storage filling 2, and the removal of heat takes place by the heat transfer device 4, which is surrounded by the vapor of the heating medium. Heat supply and heat removal occur through triple phase transitions.

If heat is supplied above the melting temperature, the material thread II evaporates. When the substance system II encounters the unmelted material of the substance system II, it condenses, and the substance system I melts. The heat of condensation released by the material system (1) is absorbed by the material system I as heat of fusion.

If heat is removed below the melting temperature, the material of system II is evaporated again, but in this case at a lower pressure than when the heat is supplied. The heat of vaporization required for this is taken away from the storage material (substance system X), which then solidifies.

The vapor of substance system II is condensed by the heat transfer device 4, and the generated heat of condensation is absorbed into the heat transfer liquid M4. .

In both cases, the heat transfer takes place with significant foaming due to the uniform mixing of the storage filler, so that an evenly distributed heat absorption or heat release occurs throughout the storage material. This known process occurs in the absence of a material system (1) in which the material melts without decomposition, resulting in large amounts of agglomeration, bonding, and skin. This can be avoided by adding substance system ①. Depending on the intensity of foaming and the amount of material system ■, a small amount of crystals will be generated,
The crystals create a spongy, permeable deposit inside the storage device.

Material system (2) is necessary to cause crystallization during heat transfer and to avoid supercooling.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a latent heat storage device according to an embodiment of the present invention. 1... Container, 2... Four types of material systems I, II, II
Filling containing I and IV, 5... Heat transfer device for supplying heat, 4... Heat transfer device for removing heat, 5... Vacant space

Claims (1)

[Claims] 1. A latent heat storage device having a substance that melts without decomposition and an active storage filling to be mixed in the storage container, wherein the active storage filling is a four-material system. I, II,
III and IV, the material system I consists of one or several materials, which have the property of accumulating heat based on the heat of transition of the materials and the specific heat capacity of the materials, and decompose upon melting. Mg(NO_3)_2 in a proportion of 50 to 95 vol. %, based on the total volume of the active accumulation filling, without exhibiting any phenomenon, e.g. eutectic or concordant, homogeneous melt.
・Create a eutectic mixture consisting of 6H_2O and MgCl_2.6H_2O, and material system II consists of a liquid as a heating medium containing one or several types of components, and the liquid is a material system II.
It does not have the ability to dissolve I or has the ability to dissolve it only conditionally, and the density of the material system II (ρ
_II) and the density of the molten phase of material system I (ρ_ I ) satisfy the condition ρ_ I ≦ρ_II, and the vapor pressure of material system I (P_D_ I )
The vapor pressure (P_D_II) of material system II satisfies the following condition: P_D_ I <<P_D_II2, the ratio of material system II to the total volume of the active accumulation filling is 3 to 50 vol%, and material system III is a material system consisting of one or several surface-active substances and for the total volume of said active storage filling;
The proportion of III is from 0.01 to 5 vol%, the substance system IV consists of one or several nucleating agents, and the proportion of substance system IV to the total volume of the active storage filling is from 0 to 20 vol%. A latent heat storage device characterized by: