KR-20260066430-A - THERMAL STORAGE APPARATUS

Abstract

The present invention relates to a heat storage device. The heat storage device according to the present invention is a packed bed type heat storage device comprising a heat storage chamber having an inlet for a heat transfer fluid to flow in and an outlet for the heat transfer fluid to flow out, 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 gap between them. The heat storage device comprises a flow rate control unit that controls the flow rate of the heat transfer fluid flowing into the heat storage chamber, and in the process of storing thermal energy in the heat storage material or releasing thermal energy from the heat storage material, the flow rate control unit controls the flow rate of the heat transfer fluid flowing in differently over time.

Inventors

• 김정철
• 류진우
• 문선영
• 박상진
• 송찬호

Assignees

• 한국기계연구원

Dates

Publication Date

20260512

Application Date

20241104

Claims (7)

1. A packed bed type thermal storage device comprising: a thermal storage chamber having an inlet for a heat transfer fluid to flow in and an outlet for the heat transfer fluid to flow out; 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 void between them. The above thermal storage device includes a flow rate control unit that controls the flow rate of the heat transfer fluid flowing into the thermal storage chamber, and A heat storage device characterized in that, in the process of storing heat energy in the heat storage material or releasing heat energy from the heat storage material, the flow rate control unit controls the flow rate of the heat transfer fluid flowing in differently over time.
2. In Article 1, A heat storage device characterized in that, when storing heat energy in the heat storage material or releasing heat energy from the heat storage material, the flow rate control unit reduces the flow rate of the heat transfer fluid flowing in stepwise or continuously.
3. In Article 2, It further includes a temperature measuring unit for measuring the temperature of the rear end of the heat storage chamber where the heat transfer fluid flows out, A heat storage device characterized in that, when storing heat energy in the heat storage material or releasing heat energy from the heat storage material, the flow rate control unit controls the flow rate of the heat transfer fluid based on the temperature value measured by the temperature measuring unit.
4. In Article 1, A heat storage device characterized in that the sizes of the heat storage material within the heat storage chamber are different along the flow direction of the heat transfer fluid.
5. In Paragraph 4, A heat storage device characterized in that the size of the heat storage material on the inlet side is larger than the size of the heat storage material on the outlet side.
6. In Article 1, A heat storage device characterized in that the types of the heat storage material within the heat storage chamber are different along the flow direction of the heat transfer fluid.
7. In Article 6, A heat storage device characterized in that the heat storage material on the inlet side is formed of a material having lower thermal conductivity than the heat storage material on the outlet side.

Description

Thermal Storage Apparatus The present invention relates to a heat storage device, and more specifically, to a heat storage device of the packed bed type that can store heat in a heat storage material using a heat transfer fluid as a medium or release heat from the heat storage material for use. 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. Figure 1 is a graph illustrating a thermocline for the ideal use of a thermal storage device. FIG. 2 is a drawing illustrating a thermal storage device according to one embodiment of the present invention. Figure 3 is a diagram showing the temperature distribution within a heat storage chamber over time when the flow rate of the incoming heat transfer fluid is decelerated after a certain period of time, as the heat transfer fluid flows from left to right within the heat storage chamber and stores heat in the heat storage material. Figure 4 is a diagram showing the temperature distribution within the heat storage chamber over time when the flow rate of the heat transfer fluid changes at different times. FIG. 5 is a drawing illustrating a thermal storage device according to another embodiment of the present invention. FIG. 6 is a diagram showing the temperature distribution over time in the case where heat is stored using heat storage materials of different materials according to another embodiment of the present invention. 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 i