JPS59200192A - Latent heat type heat accumulating device - Google Patents

Abstract

PURPOSE:To obtain stable, high temperature heat exchange output by a structure wherein latent heat type heat storage material, heat transfer medium, which is practically non-compatible with said heat storage material and changes itself from liquid to gas by absorbing heat and from gas to liquid by releasing the heat again, and foam, the apparent specific gravity of which is smaller than that of the heat storage material, are sealed in a heat storage tank under the condition that a space is left at the upper portion in the interior of the heat storage tank. CONSTITUTION:A heat accumulating device consists of heat exchangers 5 and 6 and a heat storage tank 2, which is provided with heat insulating layer and in which heat storage material 3 such as trihydrosodium acetate salt, heat transfer medium 4, which is non-compatible with the heat storage material 3 and has larger density, such as Freon 113, and foam 9, the apparent specific gravity of which is smaller than that of the heat storage material 3, such as ceramic foam, are sealed. When low temperature heat transfer medium is flowed in the heat exchanger 6 under the condition that the heat accumulating device 1 is at the state that enough heat is stored, the heat storage material filled in the tank 2 is stirred by the evaporation- condensation cycle of the heat transfer medium 4 and at the same time the heat transfer medium 4 release its heat at the heat exchanger 6 by heat-exchanging. At this time, the temperature in the space above the heat storage material filled in the tank 2 drops. However the temperature drop at the upper part of the heat storage material is prevented by the existence of the layer of the foam 9, which is onto the upper part of the heat storage material filled in the tank because of its density being smaller than that of the heat storage material.

Description

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

Conventional configuration and its problems FIG. 1 shows a conventional heat storage device 1. As shown in FIG.

A heat storage device 1 includes a heat storage material 3 in a heat storage tank 2, which changes from a liquid to a gas when absorbing heat, and from gas to a liquid when releasing heat, and the density of the condensed liquid is at least the phase transition point of the heat storage material. A heat transfer medium 4 having a density higher than that in the vicinity is sealed in the container leaving a space, and a heat exchanger 5 for storing heat and a heat exchanger 6 for extracting heat are housed. . In the heat storage state, the heat storage material filling part is made of a heat storage material solution having a temperature equal to or higher than the melting point of the heat storage material 3, and the space part is made of the saturated vapor pressure of the heat transfer medium at that temperature.

When the low-temperature heat medium is introduced into the heat exchanger 6, the heat transfer medium in the space exchanges heat with the heat exchanger 6 and is condensed and liquefied, so that the vapor pressure in the space decreases. In order to compensate for this, the heat transfer medium evaporates from the heat storage material filled part, becomes bubbles γ, rises, and reaches the space. On the other hand, the condensation ring 8 drips and flows back into the heat storage material filling section. Since the condensate 8 dropped into the heat storage material filling part has a higher density than the heat storage material 3, it descends in the heat storage material solution. While descending, most of the heat absorbs heat from the heat storage material 3, evaporates, and rises in the form of bubbles. The other part settles to the bottom of the heat storage tank 2, where it gains heat and evaporates again. However, as can be seen from the above explanation, the condensed liquid evaporates mainly in the upper part of the heat storage material filling part, and therefore, although the upper part is vigorously stirred, the stirring becomes gentler as it goes to the lower part.

The heat storage material that has lost its heat to the condensate 8 is still agitated by air bubbles, so it becomes microcrystals and is floating, but it gradually settles because it has a higher density than the liquid state. . In this manner, the heat storage material filled portion is agitated through the evaporation-condensation cycle of the heat transfer medium 4, and heat is efficiently exchanged in the heat exchanger 6. However, the temperature of the upper part of the heat storage material filling part decreases.

This is composed of a relatively low-temperature condensate that drips from the top, a relatively low-temperature heat storage material that has lost its latent heat to the condensate, and has become microcrystalline, and a heat storage material solution that has a relatively low temperature. To become. When the upper temperature decreases, the equilibrium temperature of the vapor in the space decreases. Therefore, the heat exchange temperature in the heat exchangers and the like decreases, so that the temperature rise value of the low-temperature heat medium decreases.

As can be seen from the above explanation, in conventional heat exchange, the temperature of the space decreases over time, and the heat exchange efficiency decreases, so the introduced low-temperature heat medium cannot be extracted as a high-temperature heat medium at a constant temperature. Ta.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, prevent a decrease in heat exchange performance of a radiator due to a decrease in the upper temperature of a heat storage material, and obtain a stable heat exchange output at high temperatures.

Structure of the Invention In order to achieve the above-mentioned object, the present invention provides a latent heat storage material, which is almost incompatible with the latent heat storage material, and which is capable of transferring heat from a liquid to a gas when absorbing heat, and from a gas to a liquid when releasing heat. A heat medium and a foam whose specific gravity is apparently lower than that of the heat storage material are sealed in a heat storage tank, leaving a space above the inside.

With this configuration, it is possible to prevent a temperature drop in the upper part of the heat storage material filling part and a temperature drop in the entire steam that occurs during heat extraction, and to obtain a stable heat exchange output at a high temperature.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 2. Note that in FIG. 2, the same parts as in FIG. 1 are given the same numbers.

In FIG. 2, a heat storage device 1 has a structure including a heat storage tank 2 provided with a heat insulating layer and heat exchangers 5 and 6. In the heat storage tank 2, there is acetic acid, IJium trihydrate (melting point 58
°C, the density of the melt near the melting point is 1.28. ! Heat storage material 3 such as 9/i) and Freon 113 (density 1.4 at 58°C)
A heat storage material 3 such as 87/i), an incompatible heat transfer medium 4 having a high density, and a foam 9 having a density that is apparently higher than that of the heat storage material 3 such as a ceramic foam having open pores are enclosed. ing. Unfortunately, in order to improve heat exchange efficiency, non-condensable gas within the heat storage tank 2 is excluded.

When a low-temperature heat medium flows into the heat exchanger 6 when the heat storage device 1 is in a heat storage state, the heat storage material filled part is agitated by the evaporation-condensation cycle of the heat transfer medium 4, as explained in FIG. At the same time, the heat transfer medium exchanges heat in the heat exchanger 6 and radiates heat. At this time, as explained above, the temperature of the upper part of the heat storage material filling section is lowered. In this embodiment, nine layers of foam are present above the heat storage material filling part because of their low density, and this prevents the temperature above the heat storage material from decreasing. The reason for this is not clear, but it is thought to be as follows.

The foam 9 sealed in the heat storage tank 2 has a low density;
A floating layer is formed on top of the heat storage material when the heat storage material is melted. When a foam having open pores and divided into volumes d is used as the foam 9, the heat transfer medium absorbs heat from the heat storage material 3, vaporizes, and moves to the space. In this case, there is little resistance to the flow of the vapor. Therefore, the amount of evaporation of the heat transfer medium is not affected by the inclusion of the foam 9. On the other hand, when the heat transfer medium condensate 8 flows back to the heat storage material 3, it passes through the floating layer of the foam 9 having continuous pores, but since it is a liquid and has a large viscous resistance, it encounters considerable resistance in passing. The condensate 8 therefore collects on top of the foam floating layer S 8'. When the amount of accumulated condensate 8' increases, it breaks the floating layer of the foam 9 due to its own weight and moves to the heat storage material 3 through a channel 10.
A large amount of condensate 8' flows back through this passage.

In the above case, since the reflux of the condensate is mostly carried out through the several passages 1o formed on the surface, the contact between the upper part of the heat storage material 3 and the condensate 8 is not made over the entire surface as in the conventional case, but through the surface. Since this is carried out on only a small portion of the heat storage material, it is possible to prevent the temperature from decreasing on the surface of the heat storage material.

Unfortunately, the condensate must flow back into the heat storage material in a larger amount than on a portion of the surface of the heat storage material, so it takes time for the entire material to re-evaporate as it absorbs heat from the heat storage material. Therefore, the condensate 8 can settle to the lower part of the heat storage tank 2, and the heat in the lower part can be fully utilized, and since stirring is generated from the lower part, the heat in the tank can be effectively taken out. Such a condensate pool 8' becomes larger if the foam 9 has better wettability with respect to the heat transfer medium than the heat storage material 3.

Therefore, if the foam 9 has better wettability to the heat storage material 3 than the heat transfer medium 9, the foam 9 may be surface-treated and the heat storage material 3
By improving the wettability with respect to the heat transfer medium, the above effect can be enhanced and the hot water tapping characteristics can be improved.

Further, since the foam 9 generally has heat insulating properties, even if the condensed and liquefied low-temperature liquid temporarily stays in the upper part of the foam, its temperature is not directly transmitted to the upper part of the heat storage material 3. Therefore, the entire surface of the upper liquid surface of the heat storage material 3 is cooled by the low-temperature condensed liquid.

In the above description, the case where the foam 9 having continuous pores was divided into several d parts in volume was explained. The reason for this division is that the contact points (
This is because the condensed liquid is made easier to flow back into the heat storage material 3 than the interface). Therefore, the same effect as described above can be obtained by using a large-area foam 9 and providing a means for refluxing the condensate, for example, by providing holes at several locations. On the other hand, if the volume, crushing, or surface area of the foam 9 is reduced and made into a powder, the foam 9
Although the effect of the open pores inside is eliminated, the heat transfer medium vapor easily reaches the space through the interface of the powder foam. Also,
Since the condensed liquid has a higher viscosity than gas, it stays on the upper part of the powder foam layer, and almost the same effect as described above can be obtained.

Effects of the Invention According to the device of the present invention, (a) The condensed and liquefied heat transfer medium passes through the foam section and is refluxed to the lower part of the heat storage tank, so that most of the condensed liquid in the upper part of the heat storage tank becomes the heat storage material. It can't be solved by heat exchange.

(b) Since bubbles are also generated from the lower part of the heat storage tank, the entire heat storage tank is well stirred.

(c) Since the foam is a type of heat insulating material, the temperature of the low-temperature condensate that has accumulated above it is not transmitted to the upper part of the heat storage material.

For the above-mentioned reason, there is no temperature drop in the upper part of the heat storage material, so the temperature of the heat transfer medium vapor does not drop and is maintained at a high temperature. Therefore, it is possible to prevent the heat exchange performance of the radiator from deteriorating and to obtain stable heat exchange output at high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional latent heat storage device, and FIG. 2 is a sectional view showing an embodiment of the latent heat storage device of the present invention. 1... Latent heat storage device, 2... Heat storage tank, 3
... heat storage material, 4- ... heat transfer medium, 9 ... foam. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] A latent heat storage material, a heat transfer medium that is almost incompatible with the latent heat storage material and changes from liquid to gas when absorbing heat and from gas to liquid when releasing heat, and has an apparent specific gravity smaller than that of the latent heat storage material. A latent heat storage device in which a foam is enclosed in a heat storage tank with a space left above.