JPS58104495A - Latent heat type heat accumulating device - Google Patents

Abstract

PURPOSE:To make it possible to perform a heat exchange operation quickly by a method wherein the titled heat accumulating device is formed by a heat accumulating vessel containing therein a latent heat accumulating material and an operation liquid having a specific gravity greater than that of the heat accumulating material in its molten condition and the heat exchange operation is performed by a heat exchanger arranged in a solution of the heat accumulating material. CONSTITUTION:When the heat accumulating material 2 in the vessel 1 is in its molten condition, a part of the operation liquid 3 is dissolved in the heat accumulating material 2 and the remaining part of the liquid 3 which is small in quantity moves in the heat accumulating material 2 as it becomes bubbles 9. In this case, when a low temperature heat medium is flowed into the heat exchanger 4, it immediately exchanges heat with the heat accumulating material so that the balance of heat in the vessel 1 is lost and the operation liquid 3 loses its balance due to a temperature difference to thereby make itself bubbles. Then the bubbles of the liquid 3 move toward the heat exchanger 4 for the exchange of heat so that they are condensed and liquefied to precipitate on the bottom of the vessel 1. However, the operation liquid thus liquefied becomes bubbles again in the course of its precipitation by absorbing heat from the heat accumulating material and the bubbles move upward. Thus, by the repetition of the above process, the heat accumulating material 2 releases its heat as it is agitated. On the other hand, when heat is to be accumulated, hot water is flowed into the heat exchanger 4 or the whole of the heat accumulating vessel 1 is heated or an exclusive heater may be provided for the vessel 1 to thereby accumulate heat easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a latent heat type heat storage device that stores solar energy, late night power energy, etc. in the form of thermal energy using a latent heat type heat storage material.

Conventionally, inorganic salts, paraffin, etc. have been used as this type of latent heat storage material, but one of the problems in either case is that heat exchange cannot be performed quickly.

For example, as shown in FIG. 2, the temperature of the molten latent heat type heat storage material 2 provided in the heat storage tank 1 is almost uniform due to convection. When the heat medium flows in from the inlet 6, it exchanges heat with the latent heat type heat storage material 2 in the heat exchanger 4, becomes a high-temperature heat medium, and is transferred to the heat exchanger 4.
It flows out from the outflow lower connected to. Once the latent heat type heat storage material 2 that has radiated heat to the heat medium begins to solidify, heat transfer from the surroundings deteriorates, and the temperature of the latent heat type heat storage material 2 near the heat exchanger 4 drops rapidly. That is, the latent heat type heat storage material 2 in the immediate vicinity of the heat exchanger 4 emits latent heat and solidifies 21 . When the latent heat type heat storage material 2 solidifies, its thermal conductivity deteriorates, making it difficult to transfer the heat of the latent heat type heat storage material 2 in a molten state to the heat exchanger 4.

In addition, the latent heat type heat storage material 2 is in a solid phase near the heat exchanger 4, and is in a liquid phase a little further away.
There is a method of providing fins on the heat transfer surface of the latent heat storage material 2 to shorten the distance to the liquid phase of the latent heat storage material 2, and extracting latent heat from the liquid phase.
Substantially, the above problem has not yet been solved.

The present invention provides a heat exchange device configured using a latent heat type heat storage material,
At least a working fluid having a specific gravity greater than the specific gravity of the latent heat type heat storage material in a molten state, and by configuring the structure to perform heat exchange with a heat exchanger provided in the solution of the latent heat type heat storage material, This eliminates the above-mentioned conventional drawbacks.

An embodiment of the latent heat type heat storage device of the present invention will be explained below based on FIG.

Note that the same members as those of the conventional latent heat type heat storage device will be described with the same reference numerals.

In FIG. 1, reference numeral 1 denotes a heat storage tank of a heat exchange device, and in this heat storage tank 1 there is a latent heat type heat storage material 2 and a working fluid 3 having a specific gravity that is at least larger than the specific gravity of the latent heat type heat storage material 2 in its molten state. is included. Reference numeral 4 designates a plurality of heat exchangers provided in the latent heat type heat storage material 2 in the heat storage tank 1, and the heat exchangers 4 are connected to each other through piping 6. 6 is heat exchanger 4
7 is an inlet port through which the heat medium flows into the heat exchanger 4, and an outflow port 7 through which the heat medium flows out from the heat exchanger 4. Reference numeral 8 denotes a space provided within the heat storage tank 1, which is used to relieve pressure increase within the heat storage tank 1 when the latent heat type heat storage material 2 expands. Therefore, if the heat storage tank 1 is made of a material with strong mechanical strength, it is not necessary to provide this space 8.

In such a configuration, when the latent heat type heat storage material 2 is in a molten state, a part of the working fluid 3 is dissolved in the latent heat type heat storage material 2, and the other part forms bubbles 9 due to heat transfer due to incomplete insulation performance. However, since the amount thereof is small, the latent heat type heat storage material 2 is not stirred.

However, when a low-temperature heat medium flows in from the inlet 6 provided in the heat exchanger 4, heat exchange is immediately performed in the heat exchanger 4, and the thermal equilibrium state is greatly disrupted. That is, a temperature difference occurs between the temperature of the latent heat type heat storage material 2 near the heat exchanger 4 and the temperature of the other portion away from the heat exchanger 4.

Due to this temperature difference, the hydraulic state of the working fluid 3 collapses, and the working fluid 3 turns into bubbles and moves toward the heat exchanger 4, giving heat to the low-temperature heat medium through the heat exchanger 4. , Heat: - The working fluid 3 condenses and liquefies while heating the medium.

When the working fluid 3 is condensed and liquefied, it settles in the latent heat type heat storage material 2 because its specific gravity is greater than that of the latent heat type heat storage material 2 . Then, as it sinks, it absorbs heat from the latent heat type heat storage material 2 and rises again as bubbles 9. By repeating the vaporization and condensation of the working fluid 3, the latent heat type heat storage material 2 in the heat storage tank 1 is vigorously stirred, and in the process, the heat of the latent heat type heat storage material 2 is released to the heat medium, and the latent heat type heat storage material 2 is solidify. However, since the latent heat type heat storage material 2 in the heat storage tank 1 is vigorously stirred by the working fluid 3, the solidified latent heat type heat storage material is prevented from adhering to the heat exchanger 4.

Further, the solid latent heat type heat storage material attached to the heat exchanger 4 is peeled off.

On the other hand, when storing thermal energy in the latent heat type heat storage material 2, it is necessary to flow hot water heated by solar heat or late-night electricity into the heat exchanger 4, or to heat the entire heat storage tank 1.
Alternatively, heat can be easily stored by providing a dedicated heater or heat exchanger in the heat storage tank 1.

Next, this embodiment will be explained in detail. First, as the latent heat type heat storage material 2, sodium acetate trihydrate [NaCH3Coo] was used.

3H201) and Freon R-113 as the working fluid 3 are respectively sealed in the heat storage tank 1, and non-condensable gas such as air is discharged from the heat storage tank 1. In this case, a crystal nucleation material that promotes crystallization of sodium acetate trihydrate may be added, but the sodium acetate trihydrate aqueous solution is stirred with Freon R-113, and the heat medium flows in the heat exchanger 4. It is not necessarily necessary to add a crystal nucleation material because the heat is easily radiated and crystallized.

The specific gravity of this sodium acetate trihydrate at the melting point of 58°C is 1.34 g/ctll, and the specific gravity of Freon R-113 at the same temperature is 1.46 g/cd.

Therefore, as mentioned above, when cold water such as tap water is flowed from the inlet 6, Freon R-113 condenses and liquefies on the surface of the heat exchanger 4 and precipitates in the sulfur-IJium acetate trihydrate solution. Heat is removed from the sodium acetate trihydrate solution and it evaporates again. By repeating evaporation and condensation of this Freon R-113, the latent heat of sodium acetate trihydrate is released to a heat medium such as tap water, and the sodium acetate trihydrate solidifies. Since the solidified sodium acetate trihydrate has a high specific gravity, it settles. Therefore, most of the latent heat of the sodium acetate trihydrate solution can be effectively extracted.

As is clear from the above description, the latent heat type heat storage device of the present invention provides the following effects.

(1) The working fluid exists as bubbles in the latent heat type heat storage material,
Since the latent heat type heat storage material is stirred by the bubbles, heat exchange with the heat medium via the heat exchanger is performed quickly and efficiently.

(2) Since the latent heat storage material is stirred by the bubbles of the working fluid,
The temperature distribution of the latent heat type heat storage material is uniform, and it does not solidify in a specific area, and there is no thick solid phase with poor heat transfer attached to the heat transfer surface of the heat exchanger, making it a latent heat type heat storage material. The latent heat of can be effectively extracted.

(3) Since the latent heat type heat storage material has a good heat exchange rate, the heat storage device can be downsized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a latent heat type heat storage device showing one embodiment of the present invention, and FIG. 2 is a sectional view of a latent heat type heat storage device shown as a conventional example. , 1... Heat storage tank (part of the heat exchange device), 2...
... Latent heat type heat storage material, 3... Working fluid, 4...
···Heat exchanger. Figure 1 Figure 2

Claims (1)

[Claims] A heat exchange device configured using a latent heat type heat storage material, and a working fluid having a specific gravity greater than at least the specific gravity of the latent heat type heat storage material in a molten state, and provided in a solution of the latent heat type heat storage material. A latent heat type heat storage device configured to exchange heat with a heat exchanger.