JPH05106983A - Heat accumulator - Google Patents

Abstract

PURPOSE:To cope with load fluctuations of a heat supply system or a heat application system by penetrating and installing a plurality of fined tubes into a shell filled with polyethylene as a latent heat accumulation material and circulating ethylene glycol as a heat transfer fluid. CONSTITUTION:Polyethylene is sealed in a shell 5 as a latent heat accumulation material where ethylene glycol is sealed in a circulation passage including the shell 5 as a heat transfer fluid. The heat transfer fluid 4 is introduced into the shell 5 as a fluid outside the pipe by driving a circulation pump 8 while a heating medium 6 which is excess waste heat from a refuse incinerator plant is introduced as a fluid inside the pipe so that the latent heat accumulation material 3 may be heated with the heating medium 6 so as to accumulate the heat in the heat accumulation material 3. During this operation, the heating medium is introduced as a convection flow to the heating medium 6 in the tubes 1 around, which makes it possible to make an equalized phase change of the heat accumulation material 3 in the shell 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage device for storing excess waste heat from a refuse incineration plant or the like and radiating the stored heat as necessary.

[0002]

2. Description of the Related Art Conventionally, a heat recovery system for recovering excess exhaust heat from a plant by a heat medium, a heat utilization system for utilizing the recovered heat via the heat medium supplied from the heat recovery system, and the above heat recovery system In the exhaust heat utilization device having a heat storage system that stores the recovered heat via the heat medium supplied from the system and radiates the stored heat to the heat utilization system in accordance with the load fluctuation of the heat utilization system, The sensible heat heat storage device shown in FIG. 4 is incorporated therein.

In FIG. 4, 11 is a sensible heat storage material (water or brick), 12 is a working gas, the working gas 2 is passed between the sensible heat storage materials 11, and the heat of the working gas 12 is transferred to the sensible heat storage material. 1
It is designed to store heat.

[0004]

In the conventional sensible heat storage apparatus shown in FIG. 6, when the heat storage material 11 is water, the heat storage density is relatively high, but when the working gas 2 reaches 100 ° C. or higher, There is a disadvantage that the heat storage device becomes a pressure vessel. On the other hand, when the heat storage material 11 is a solid heat storage material such as brick, the heat storage density is low and the sensible heat storage device becomes large,
Since the thermal conductivity of the heat storage material is low and the heat storage rate and the heat release rate are slow, it is impossible to follow the load fluctuation of the heat supply or heat utilization system.

Further, the above-mentioned conventional sensible heat storage device has a disadvantage that the output temperature gradually decreases during heat radiation. The present invention is proposed in view of the above-mentioned problems, and an object of the present invention is to process a huge amount of exhaust heat. Further, it is possible to cope with the load fluctuation of the heat supply system or the heat utilization system. Another object is to provide an exhaust heat utilization device that can obtain a stable output without reducing heat exchange performance.

[0006]

In order to achieve the above object, a heat storage device of the present invention comprises a shell filled with polyethylene as a latent heat storage material, and a shell attached to the shell in a penetrating state. It is equipped with a plurality of tubes with heat transfer fins that guide the air as a counterflow to the heat medium in the surrounding tubes, and a circulation pump that circulates ethylene glycol as a heat transfer fluid in the circulation path including the inside of the shell. ..

[0007]

The heat storage device of the present invention is configured as described above, in which polyethylene is sealed as a latent heat storage material in the shell, and ethylene glycol is sealed as a heat transfer fluid in the circulation path including the shell, and then the circulation pump is used. The heat transfer fluid is introduced into the shell as an external fluid, while the heat medium is introduced into each tube with heat transfer fins as an internal fluid, and the latent heat storage material is heated by the heat medium to generate the same latent heat. Stores heat in the heat storage material. At that time, the heat medium is introduced into each of the tubes with heat transfer fins as a counterflow to the heat medium in the adjacent tube, the solidification temperature of the entire latent heat storage material is made substantially constant, and the temperature of the latent heat storage material in the shell is reduced. The whole is uniformly phase-changed and the entire latent heat storage material is maintained at the melting point temperature, so that the temperature difference between the heat medium and the latent heat storage material is always kept constant and large. Therefore, stable output can be obtained without reducing the heat exchange performance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat storage device of the present invention will be described below with reference to an embodiment shown in FIGS. 1 and 2. 1 is a plurality of tubes, 2 is a heat transfer fin attached to the outer peripheral surface of each tube 1, 5 Is a shell of a heat accumulator, and each tube 1 with heat transfer fins is attached to the shell 5 in a penetrating state.

3 is a latent heat storage material, and the latent heat storage material 3 has
Shape-stabilized high-density polyethylene whose shape does not change even after melting is used, and the polyethylene is filled as latent heat storage material 3 in the shell 5 around the tubes 1 with heat transfer fins. 4 is a heat transfer fluid, and ethylene glycol is used for the heat transfer fluid 4. 6 is a heat medium (heat medium for heating (when storing heat) or heat medium for receiving heat (when radiating heat)), 7 is a circulation path including the inside of the shell 5, and 8 is a circulation provided in the circulation path 7 outside the shell 5. The heat transfer fluid 4 is circulated in the circulation path 7 including the shell 5 by the circulation pump 8.

Next, the operation of the heat storage device shown in FIGS. 1 and 2 will be specifically described. After sealing polyethylene as the latent heat storage material 3 in the shell 5 and ethylene glycol as the heat transfer fluid 4 in the circulation path 7 including the shell 5, the circulation pump 8 is operated to heat transfer fluid (ethylene glycol).
4 is introduced into the shell 5 as an external fluid, while the heat medium 6
Is introduced into each tube with heat transfer fins 1 as a pipe fluid, the latent heat storage material 3 is heated by the heat medium 6, and heat is stored in the latent heat storage material 3. At that time, the heat medium 6 is introduced into each of the heat transfer fin-equipped tubes 1 as a counterflow to the heat medium in the peripheral tubes (see the arrow in FIG. 1).

The heat transfer performance between the heat medium 6 in the tube 1 with heat transfer fins and the latent heat storage material 3 made of polyethylene is as follows: thermal resistance of fluid in tube, thermal resistance of tube, thermal resistance of fluid in shell, heat storage Determined by the sum of the thermal resistance of the materials. Of these, the heat transfer performance is governed by the thermal resistance of the fluid in the shell and the resistance of the heat storage material. When ethylene glycol is used as the heat transfer fluid 4, this is applied to the circulation path 7 including the inside of the shell 5. If it circulates,
The heat transfer coefficient is greatly improved and the thermal resistance of the fluid in the shell is reduced.

When the heat medium 6 in the tube with heat transfer fins 1 is caused to flow in a certain direction, as shown in FIG. 3 (a), a large amount of heat is exchanged at the shell 5 inlet of the heat accumulator, and at the inlet,
The solidification rate of the heat storage material increases. Therefore, as shown in FIG. 3 (b), the heat storage material 3 is completely solidified at the inlet of the shell 5 of the heat storage device as the time elapses, the temperature also drops below the melting point, the amount of heat exchanged decreases, and the tube 1 The outlet temperature of the heat medium 7 inside also falls.

On the other hand, when the heat medium 6 is introduced into each tube 1 as a counterflow with respect to the heat medium in the surrounding tubes as described above, as shown in FIG. 3 (c), the entire heat storage material 3 is solidified. The temperature becomes substantially constant, the entire heat storage material 3 in the shell 5 undergoes a uniform phase change, and the entire heat storage material 3 maintains the melting point temperature,
The temperature difference between the heat medium (for example, water) 6 and the heat storage material 3 is constantly large. Therefore, stable output can be obtained without reducing the heat exchange performance.

[0014]

As described above, in the heat storage device of the present invention, the shape-stabilized high-density polyethylene filled in the shell as a latent heat storage material stores and dissipates excess waste heat at a melting point of 127 ° C. Moreover, the polyethylene is a solid-liquid change, the shell side does not become a pressure vessel, and it is possible to increase the capacity and process a huge amount of waste heat.

On the other hand, the heat medium (for example, water) flowing in the fin-equipped tube operates at a temperature of about 150 ° C. during heat storage and 127 ° C. during heat radiation, so that pressurization of about 5 ata is required. The tube has heat transfer fins on its outer circumference. In addition, since ethylene glycol filled as a heat transfer fluid in the shell is forcedly circulated, the rate of storage and heat dissipation is increased, and it is possible to cope with load fluctuations in the heat recovery system or heat utilization system.

Further, polyethylene is enclosed in the shell as a latent heat storage material, ethylene glycol is enclosed as a heat transfer fluid in a circulation path including the shell, and then a circulation pump is operated to externally transfer the heat transfer fluid into the shell. While being introduced as a fluid, a heat medium is introduced into each tube with heat transfer fins as a pipe fluid, the latent heat storage material is heated by the heat medium, and heat is stored in the latent heat storage material. At that time, a heat medium is introduced into each tube with heat transfer fins as a counterflow to the heat medium in the surrounding tubes, and the solidification temperature of the entire latent heat storage material is made substantially constant, so that the latent heat storage material in the shell is The entire phase of the latent heat storage material is uniformly changed to maintain the melting point temperature, and the temperature difference between the heat medium and the latent heat storage material is constantly set to a large constant value, so that stable output is achieved without reducing the heat exchange performance. Can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a heat storage device of the present invention.

FIG. 2 is a plan view of the heat storage device.

FIG. 3 is an explanatory diagram showing heat exchange performance between a heat storage material and a heat medium.

FIG. 4 is an explanatory diagram showing a conventional heat storage device.

[Explanation of symbols]

 1 tube 2 heat transfer fin 3 latent heat storage material (polyethylene) 4 heat transfer fluid (ethylene glycol) 5 shell of heat storage device 6 heat medium 7 circulation path 8 circulation pump

Claims (1)

[Claims] 1. A shell filled with polyethylene as a latent heat storage material, and a plurality of heat transfer units mounted in the shell in a penetrating state to introduce a heat medium into each of them as a counterflow to a heat medium in a peripheral tube. A heat storage device comprising a finned tube and a circulation pump for circulating ethylene glycol as a heat transfer fluid in a circulation path including the inside of the shell.