JPS58213190A - Heat accumulator - Google Patents

Abstract

PURPOSE:To obtain a hot water tapping characteristic with high reproducibility and efficiently tap hot water at a fixed temperature, by a method wherein a latent heat type heat-accumulating material, a heat-transmitting material having a density higher than that of a melt of the heat-accumulating material at a temperature approximate to its melting point and a substance compatible with the heat-accumulating material are sealed in a heat-accumulating container. CONSTITUTION:The latent heat type heat-accumulating material 3, the heat- transmitting material 4 having a density higher than that of the melt of the material 3 at a temperature approximate to its melting point and the substance 31 compatible with the material 3 are sealed in the heat-accumulating container 2, leaving a space part 5. When accumulating heat, a non-soluble floated part of the material 3 generated at an upper part thereof is dissolved, and when releasing heat, the rise in the viscosity of the melt of the material 3 is small, and bubbles can be easily floated up. Accordingly, a hot water tapping characteristic with high reproducibility can be obtained, and hot water of a fixed temperature can be efficiently tapped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat storage device using a latent heat type heat storage material that stores late-night electricity, solar energy, etc. and is used for hot water supply, air conditioning, and the like.

Conventionally, in a heat storage device using a latent heat type heat storage material, in order to quickly exchange heat, the heat storage material is sealed together with a heat transfer medium, and the heat transfer medium absorbs heat from the heat storage material and transfers that heat through gas phase heat exchange. Heat exchange was performed using a container. That is, in FIG. 1, the heat storage material 3 in the container 2 of the heat storage device 1 has a density greater than the density in the molten state of the heat storage material, and the phase changes from liquid to gas when heat is absorbed, and from gas to liquid when heat is released. A space 5 for exchanging heat with the heat transfer medium 4
Leave and enclose. Furthermore, the heat storage device 1 includes a heating device 6 for adding heat and a heat exchanger 7 for taking out heat.
is provided.

Usually, the outer periphery of the container 2 is covered with a heat insulating material to prevent heat dissipation, but this is not shown in the figure.

When low-temperature water is introduced into the heat exchanger 7 in the heat storage state, the steam of the working fluid occupying the space 5 imparts its latent heat to the heat exchanger and is condensed and liquefied. Therefore, the vapor pressure in the space decreases, and the working fluid 4 newly takes heat from the heat storage material 3 and evaporates, forming bubbles 8 and rising through the heat storage material filled portion to compensate for the drop in air pressure. On the other hand, since the condensed working fluid 4 has a higher density than the heat storage material, it settles in the heat storage material 3. This evaporation-condensation cycle causes self-agitation in the heat storage material 3, allowing heat to be extracted more effectively. In order to perform stable heat exchange with this method, it is necessary that the evaporation-condensation cycle be performed stably. However, in the conventional heat storage device, when the heat storage material melts, an insoluble substance floats on top of the heat storage material as shown in FIG. 2, which inhibits the evaporation of air bubbles. However, during heat dissipation, the heat storage material that has released latent heat becomes fine crystals. Since this has a higher density than the molten heat storage material, part of it settles, but the other part mixes with the molten heat storage material by the stirring action. This increased the apparent viscosity of the molten heat storage material layer, inhibited the stirring action, and also prevented the bubbles from rising through the heat storage material and reaching the gas phase.

Therefore, conventional heat storage devices have poor reproducibility;
It was difficult to obtain hot water at a constant temperature.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat storage device that can solve the above problems and perform heat exchange quickly and efficiently.

The present invention relates to a latent heat type thermal material, a heat transfer medium which has a density greater than the density of the melt near its melting point, and whose phase changes from liquid to gas when absorbing heat and from gas to liquid when releasing heat, and the heat storage material. and a substance that is compatible with the heat storage container are sealed in a heat storage container leaving a space. There are two configurations in the present invention. The first configuration is to add an amount of a substance that is compatible with the heat storage material by a factor of 3 or less in terms of the weight ratio of the heat storage material.This will dissolve the insoluble floating material of the heat storage material that forms on the top of the heat storage material during heat storage. No, the gas-liquid interface becomes only the melt, and the bubbles easily scatter into the space. The second configuration is such that the amount of the substance that is compatible with the heat storage material is 3 in terms of the weight ratio of the heat storage material.
~20%. As a result, during heat storage, insoluble heat storage material floating matter that occurs on the top of the heat storage material is dissolved, and during heat dissipation, there is little increase in the viscosity of the heat storage material melt, and bubbles can easily rise. can be obtained.

An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 in the description of the first configuration is a heat storage device. The heat storage container 2 is filled with a heat storage material composition 31 in which a heat storage material such as acetic acid (IJum trihydrate) is added with a substance compatible with the heat storage material, such as water, and the density of the melt near the melting point of the heat storage material is further increased. It has a greater density and changes from liquid to gas when absorbing heat,
A heat transfer medium 4, such as trichlorotrifluoroethanefluorocarbon 113, which changes its phase to gas when heat is released, is sealed leaving a space 5. Furthermore, the heat storage container 2 is provided with a heating device 6 and a heat exchanger 7 for extracting heat. In the above case,
Because it contains more than the stoichiometric amount of water, insoluble substances such as anhydrous sodium acetate may form at the gas-liquid interface (corresponding to Figure 2, 9) in the heat storage container when sodium acetate trihydrate is used for heat storage. do not have. Therefore, when low-temperature water is introduced into the heat exchanger 7, the freon 113 releases latent heat and condenses in the heat exchanger 7. As a result, the vapor pressure in the space 5 decreases, but this is compensated for by the evaporation of the fluorocarbon 113 in the heat storage material.

In this case, as described above, since no insoluble substances exist at the gas-liquid interface, the evaporation-condensation cycle is carried out smoothly.

Since there is nothing that disturbs the evaporation-condensation cycle, the reproducibility is good.

In order to prevent the formation of the insoluble substances mentioned above, it is sufficient to add substances that are compatible with the heat storage material as mentioned above.
The amount thereof may normally be 1 to 2% by weight compared to the weight of the heat storage material, and it is sufficient to add 3% by weight.

The second configuration will be explained. The second configuration is the same as the first configuration, except that the amount of a substance compatible with the heat storage material, such as water, in the heat storage material composition is different. That is, the second configuration is characterized in that 3 to 20 weight percent of water is added to the weight of the heat storage material. This prevents the formation of insoluble substances at the gas-liquid boundary of the heat storage container, prevents the viscosity of the heat storage material from increasing during tapping (during heat dissipation), and efficiently extracts heat.

During heat dissipation, the heat storage material solution imparts thermal energy to the heat transfer medium and fixes it. In this case, since the heat storage material is vigorously stirred by the heat transfer medium as described above, the solidified heat storage material becomes microcrystals and is partially mixed into the heat storage material melt, increasing the viscosity of the heat storage material melt.

However, in the present invention, since a hydraulic agent which is non-coagulable during actual use is included, an increase in viscosity can be prevented.

Furthermore, a part of the solidified heat storage material settles to the lower part of the heat storage container. Therefore, since the heat storage material solution accumulates at the top of the heat storage container and the amount of water in the container is constant, the proportion of water contained in the solution increases, which causes an increase in the viscosity of the solution. become. Therefore, the bubbles 8 of the heat transfer medium generated in the heat storage material solution can easily rise in the solution and scatter into the gas phase. FIG. 4 is an example showing the effect of the present invention. When sodium acetate trihydrate and Freon 113 are mixed in a heat storage container with an actual capacity of 100L, heat is stored at 60°C by varying the amount of water filled, and 16°C cold water is introduced into the heat exchanger 7, the temperature will exceed 50°C. It shows where the hot water can be obtained.

From Figure 4, the amount of hot water that comes out when the water amount is 3% or less does not change much. This is because this amount of water has almost no effect on inhibiting viscosity increase. Furthermore, if the amount of water exceeds 20% by weight, the amount of hot water delivered above 50°C will decrease. This is because the ratio of sensible loss (amount of water) occupying the heat storage container increases, and the heat storage density decreases. Therefore, the amount of water is practically preferably 3 to 20% by weight. The above explanation assumes that sodium acetate trihydrate is used as the heat storage material, water is used as the material compatible with the heat storage material, and Freon 113 is used as the heat transfer medium. Although described above, the material is not limited to this, and it goes without saying that other materials having properties equivalent to the above materials may be used.

In addition, in the above explanation, the heat exchanger is a space part (gas phase part)
Although we have explained the case where there is a gas-liquid phase, similar results can be obtained even if heat exchangers exist for both gas and liquid phases.

As can be seen from the above description, by using the heat storage device of the present invention, hot water discharge characteristics with good reproducibility can be obtained, and hot water at a constant temperature can be efficiently obtained.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a conventional heat storage device, FIG. 3 is a cross-sectional view of a heat storage device of the present invention, and FIG. 4 is a diagram showing the relationship between the amount of water contained in the heat storage container and the hot water output characteristics. 1... Heat storage device, 3... Heat storage material, 4.
... Heat transfer medium, 31 ... Heat storage material composition. Figure 1 Figure 2 Figure 3 Figure 4 H20 amount vtt%

Claims (3)

[Claims] (1) Heat storage in which a latent heat type heat storage material, a heat transfer medium having a density higher than the density of the melt near the melting point of the heat storage material, and a substance having compatibility with the heat storage material are sealed in a heat storage container leaving a space. Device. (2) The heat storage device according to claim 1, wherein the substance having compatibility with the heat storage material is water, and the weight ratio to the heat storage material is 3% or less. (3) The heat storage device according to claim 1, wherein the substance having compatibility with the heat storage material is water, and the weight ratio to the heat storage material is 3 to 20 inches.