KR-20260066425-A - THERMAL STORAGE SYSTEM

Abstract

The present invention relates to a thermal storage system, wherein the thermal storage system according to the present invention comprises a thermal storage chamber having an inlet for a heat transfer fluid and an outlet for the heat transfer fluid to be discharged; and a thermal storage material filled inside the thermal storage chamber and storing or releasing thermal energy through heat exchange while the heat transfer fluid flows between the inlet and the outlet through a gap between them, wherein a plurality of packed bed type unit thermal storage devices are connected through connecting pipes, wherein the unit thermal storage devices are arranged in multiple stages in the direction in which the high-temperature heat transfer fluid flows, and the unit thermal storage devices at the rear end are branched in parallel from the unit thermal storage devices at the front end and connected through the connecting pipes.

Inventors

• 김정철
• 문선영
• 류진우
• 박상진
• 송찬호

Assignees

• 한국기계연구원

Dates

Publication Date

20260512

Application Date

20241104

Claims (7)

1. A heat storage system comprising a heat storage chamber having an inlet for a heat transfer fluid and an outlet for the heat transfer fluid to be discharged; and a heat storage material filled inside the heat storage chamber and storing or releasing thermal energy through heat exchange while the heat transfer fluid flows between the inlet and the outlet through a void between them, wherein a plurality of packed bed type unit heat storage devices are connected through connecting pipes. A heat storage system characterized in that the unit heat storage devices are arranged in multiple stages in the direction in which a high-temperature heat transfer fluid flows, and the unit heat storage devices at the rear stage are branched in parallel from the unit heat storage devices at the front stage and connected through the connecting pipes.
2. In Article 1, A heat storage system characterized by having a valve formed in the above-mentioned connecting pipe to control the flow of a heat transfer fluid.
3. In Article 2, A thermal storage system characterized by an increasing number of unit thermal storage devices towards the rear end.
4. In Article 1, A heat storage system characterized by using a low-temperature heat transfer fluid to release heat stored in the heat storage system, wherein the fluid is flowed in the opposite direction to the flow direction when using a high-temperature heat transfer fluid to store heat in the heat storage system.
5. In Article 1, A thermal storage system characterized by being connected in multiple stages through the above-mentioned connecting pipes, wherein the unit thermal storage devices are uniformly arranged in a matrix.
6. In Article 1, A thermal storage system characterized by having different sizes of thermal storage materials filled in unit thermal storage devices.
7. In Article 6, A thermal storage system characterized in that the size of the thermal storage material filled in the rear unit thermal storage device is smaller compared to the thermal storage material filled in the front unit thermal storage device.

Description

Thermal Storage System The present invention relates to a heat storage system, and more specifically, to a heat storage system in which a plurality of unit heat storage devices are arranged through connecting pipes to store heat in a heat storage material or release heat from a heat storage material using a heat transfer fluid as a medium in a packed bed type. In order to increase energy efficiency, a thermal storage device is essential. That is, energy efficiency can be increased by converting surplus electricity into thermal energy, storing it in a thermal storage device, and then releasing it when needed to be used as electrical or thermal energy. As a heat storage device that stores and uses sensible heat, a block and pipe type heat storage device in which a pipe is formed so that a heat transfer fluid passes through a bulk concrete, and a packed bed type heat storage device in which a heat storage material is filled inside a heat storage chamber and a heat transfer fluid passes through the gaps between the heat storage materials are known. When storing and releasing heat in the aforementioned thermal storage device, the thermocline must be given important consideration for heat utilization efficiency. In addition, the heat storage rate and heat release rate must also be given important consideration. Figure 1 is a graph illustrating a thermocline for the ideal use of a thermal storage device. To explain with reference to a pack bed type thermal storage device, for example, when storing thermal energy in a thermal storage material through a high-temperature heat transfer fluid flowing inside the thermal storage chamber from left to right in the drawing, it is ideal to store thermal energy sequentially from left to right in the thermal storage material, and conversely, when releasing thermal energy through a low-temperature heat transfer fluid flowing from left to right, it is ideal to release thermal energy sequentially from left to right in the thermal storage material. For example, after charging the entire thermal storage material with thermal energy by sequentially heating it to 300°C from left to right through a high-temperature heat transfer fluid of 300°C, it is ideal to release thermal energy from the thermal storage material sequentially from left to right when releasing heat, and to continuously release thermal energy at a temperature of 300°C. If the temperature of the entire thermal storage material inside the thermal storage chamber gradually decreases and thermal energy is released, the thermal energy is initially released at a temperature of 300°C, but as the thermal energy is gradually released at a lower temperature, the efficiency of thermal energy use may decrease. The thermocline illustrated in Fig. 1 explains the performance of such a thermal storage device. A thermal storage structure that forms a good thermocline (a large thermocline gradient) ideally stores and releases thermal energy as described above. However, if the flow rate of the heat transfer fluid is fast, the thermocline deteriorates. This is because if the flow rate of the heat transfer fluid is fast, it may flow backward without sufficiently exchanging heat with the heat storage material, and consequently, it disperses and transfers heat to the heat storage material in the direction of flow. Conversely, if the flow rate of the heat transfer fluid is slow, the thermocline improves. However, if the flow rate of the heat transfer fluid is slow, there is a problem that too much time is required to store heat in the heat storage material and to release heat from the heat storage material. To increase thermal storage capacity, a heat transfer system can be configured by arranging multiple unit thermal storage devices and connecting them via piping to allow heat transfer fluid to flow between them. In this way, even in a heat transfer system utilizing multiple thermal storage devices, the thermocline and the heat storage or heat release rate must be considered together when storing and releasing heat to improve heat utilization efficiency. Figure 1 is a graph illustrating a thermocline for the ideal use of a thermal storage device. FIG. 2 is a drawing illustrating a unit thermal storage device according to one embodiment of the present invention. FIG. 3 is a drawing illustrating a thermal storage system according to one embodiment of the present invention. Figure 4 is a diagram illustrating the flow direction of the low-temperature heat transfer fluid during the heat dissipation process in Figure 3. Figure 5 is a variation of Figure 3. Specific details of the embodiments are included in the detailed description and drawings. The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemen