Fused salt energy storage heating system

Abstract

The utility model discloses a fused salt energy storage heating system which aims at solving the problems that an existing fused salt energy storage heating system is large in heat exchange area, the heat exchange face is prone to being corroded by heat exchange media, and phase-change heat exchange is unstable, single-tank fused salt heat storage is used, system investment can be reduced, fused salt is conveyed into an oil-salt heat exchanger through a fused salt pump, and heat exchange efficiency is improved. The heat exchange surface can be prevented from being arranged in the fused salt storage tank and occupying the volume in the tank, and the problem that the heat exchange surface is not easy to maintain in the fused salt storage tank can also be avoided. In addition, fused salt serves as a heat storage medium, and a fused salt electric heater and a fused salt pump are arranged in the fused salt tank. In the off-peak electricity period or when new energy is used for abandoning electricity, electric energy is converted into sensible heat of fused salt through the fused salt electric heater to be stored in the fused salt tank. When the fused salt energy storage system releases heat, silicone oil in the oil tank is conveyed to the oil-salt heat exchanger to absorb heat, and meanwhile the fused salt pump conveys fused salt to the oil-salt heat exchanger to release heat. The silicone oil absorbing heat enters the oil-water heat exchanger, heat is transferred to heating circulating water, and the whole heat release process is completed.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of energy storage heating, especially relates to a molten salt energy storage heating system. BACKGROUND

[0002] Molten salt energy storage is a sensible heat storage technology, which utilizes the temperature difference of molten salt during the heating and cooling process to realize energy storage and release. Within the entire working temperature range, molten salt always remains in liquid state.

[0003] The existing molten salt energy storage heating system, such as the one disclosed in the publication CN115789741A, uses a single tank for molten salt energy storage. Two different media circulation loops are arranged on the inner and outer sides of the molten salt tank, which improves the volume utilization rate of the molten salt tank. The flow directions of the heat exchange media in the two circulation loops are opposite relative to the molten salt tank, which causes the molten salt in the tank to form a convection, avoiding the situation that the molten salt in the tank is hot at the top and cold at the bottom, and solving the problem of insufficient heat storage and release of the single-tank temperature-gradient heat storage system. The disadvantage is that the circulation pipeline using water as the heat exchange medium is arranged on the outside of the molten salt tank inner shell, which has a low heat exchange coefficient and a large heat exchange area.

[0004] For example, the publication CN111911989A discloses a single-tank molten salt heat storage heating system. This system uses a single tank for molten salt heat storage, and water medium heat exchange coils and foamed metal are arranged in the molten salt tank. The foamed metal is welded on the heat exchange coils to strengthen the heat exchange coefficient during the phase change of molten salt. The disadvantage is that when the molten salt solidifies after phase change and is heated again by the electric heating element, it is easy to be unevenly heated, which may cause the electric heating element to burn out or the molten salt tank body to break. SUMMARY

[0005] The utility model aims to provide a molten salt energy storage heating system, which reduces the heat exchange area and ensures the stability of the heat exchange process.

[0006] To solve the above problems, the technical scheme of the utility model is as follows:

[0007] A molten salt energy storage heating system, comprising: a molten salt tank, a molten salt electric heater, a molten salt pump, an oil-salt heat exchanger, an oil pump, an oil tank, and an oil-water heat exchanger.

[0008] The molten salt electric heater is arranged in the molten salt tank. The inlet of the molten salt pump is deep into the molten salt tank, and the outlet of the molten salt pump is connected to the first inlet of the oil-salt heat exchanger.

[0009] The second inlet of the oil-salt heat exchanger is connected to the oil tank through the oil pump. The first outlet of the oil-salt heat exchanger is connected to the molten salt tank, and the second outlet is connected to the first inlet of the oil-water heat exchanger.

[0010] The second inlet of the oil-water heat exchanger is communicated with external water inlet, the first outlet is communicated with the oil tank, and the second outlet is communicated with external water supply.

[0011] According to an embodiment of the present application, a molten salt circulation pipeline is arranged in the molten salt tank, and the inlet of the molten salt circulation pipeline is communicated with the outlet of the molten salt pump.

[0012] According to an embodiment of the present application, the molten salt circulation pipeline is arranged non-horizontally, so as to ensure that the molten salt in the pipeline automatically flows back to the molten salt tank.

[0013] According to an embodiment of the present application, a porous solid filler is arranged in the molten salt tank, so as to make the temperature change uniform and stable during the heat release process of the molten salt tank.

[0014] According to an embodiment of the present application, silicone heat-conducting oil is used as the heat transfer medium in the oil-salt heat exchanger, the oil pump and the oil tank, so as to ensure heat stability.

[0015] According to an embodiment of the present application, the second inlet of the oil-water heat exchanger is communicated with heating circulating water or domestic water supply.

[0016] According to an embodiment of the present application, the oil-water heat exchanger comprises a first oil-water heat exchanger and a second oil-water heat exchanger, the first inlet of the first oil-water heat exchanger and the first inlet of the second oil-water heat exchanger are communicated with the second outlet of the oil-salt heat exchanger.

[0017] The first outlet of the first oil-water heat exchanger and the first outlet of the second oil-water heat exchanger are communicated with the oil tank.

[0018] The second inlet of the first oil-water heat exchanger is communicated with heating circulating water inlet, and the second outlet is communicated with heating circulating water supply.

[0019] The second inlet of the second oil-water heat exchanger is communicated with domestic water supply, and the second outlet is communicated with domestic water supply.

[0020] According to an embodiment of the present application, the molten salt energy storage heating system further comprises a hot water boiler, the inlet of the hot water boiler is communicated with heating return water, and the outlet of the hot water boiler is communicated with heating water supply.

[0021] Compared with the prior art, the molten salt energy storage heating system has the following advantages and positive effects:

[0022] The molten salt energy storage heating system in the embodiment of the utility model, for the existing molten salt energy storage heating system heat exchange area is big, the heat exchange surface is easy to be corroded by the heat exchange medium, the phase change heat transfer is unstable and so on, uses single tank molten salt heat storage, can reduce the system investment, and uses the molten salt pump to deliver the molten salt to the oil salt heat exchanger, can avoid the heat exchange surface arrangement in the molten salt storage tank, occupies the tank content volume, also can avoid the emergence heat exchange surface in the molten salt storage tank is not easy to maintain the problem. And, with molten salt as heat storage medium, molten salt tank is provided with molten salt electric heater, molten salt pump. In valley electricity time period or using new energy abandoned electricity, through molten salt electric heater, the sensible heat of electric energy is converted into molten salt and stored in molten salt tank. When the molten salt energy storage system releases heat, the silicon oil in the oil tank is delivered to the oil salt heat exchanger to absorb heat, and the molten salt pump also delivers the molten salt to the oil salt heat exchanger to release heat. The silicon oil after absorbing heat enters the oil-water heat exchanger, and transfers heat to the heating circulating water to complete the entire heat release process. The system is configured with a molten salt electric heater to fully utilize the peak-valley electricity price difference, reduce heating costs, or fully utilize new energy abandoned electricity, and improve energy utilization. In addition, using oil medium heat exchange, compared with water as medium heat exchange, can reduce the corrosion of equipment. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The utility model discloses a molten salt energy storage heating system schematic diagram in an embodiment thereof.

[0024] Mark explanation:

[0025] 1: molten salt tank;2: molten salt electric heater;3: molten salt pump;4: molten salt circulating pipeline;5: porous solid filler;6: oil salt heat exchanger;7: oil pump;8: oil tank;9: first oil-water heat exchanger;10: second oil-water heat exchanger;11: hot water boiler;12: water tank. Specific implementation

[0026] The utility model discloses a molten salt energy storage heating system is further detailed in the following combining with the drawing and specific embodiment. According to the following explanation and claims, the advantages and features of the utility model will be more clear.

[0027] Please see Figure 1 The embodiment provides a molten salt energy storage heating system, comprising: a molten salt tank 1, a molten salt electric heater 2, a molten salt pump 3, an oil salt heat exchanger 6, an oil pump 7, an oil tank 8 and an oil-water heat exchanger.

[0028] The molten salt electric heater 2 is arranged in the molten salt tank 1, the inlet of the molten salt pump 3 is deep into the molten salt tank 1, and the outlet of the molten salt pump 3 is communicated with the first inlet of the oil salt heat exchanger 6;The second inlet of the oil salt heat exchanger 6 is communicated with the oil tank 8 through the oil pump 7, the first outlet is communicated with the molten salt tank 1, and the second outlet is communicated with the first inlet of the oil-water heat exchanger. The second inlet of the oil-water heat exchanger is communicated with the external water inlet, the first outlet is communicated with the oil tank 8, and the second outlet is communicated with the external water supply.

[0029] The system uses a single-tank molten salt heat storage, which can reduce system investment, and uses a molten salt pump to deliver the molten salt to the oil-salt heat exchanger, which can avoid the heat exchange surface arranged in the molten salt storage tank, occupy the tank volume, and also avoid the problem that the heat exchange surface is not easy to maintain in the molten salt storage tank. Moreover, the molten salt is used as a heat storage medium, and a molten salt electric heater and a molten salt pump are arranged in the molten salt tank. During the valley electricity period or when new energy is abandoned, the electric energy is converted into the sensible heat of the molten salt by the molten salt electric heater and stored in the molten salt tank. When the molten salt energy storage system releases heat, the silicon oil in the oil tank is delivered to the oil-salt heat exchanger to absorb heat, and at the same time, the molten salt pump also delivers the molten salt to the oil-salt heat exchanger to release heat. The silicon oil after heat absorption enters the oil-water heat exchanger to transfer heat to the heating circulating water, and the entire heat release process is completed.

[0030] Further, the molten salt tank 1 is further provided with a molten salt circulating pipeline 4, an inlet of the molten salt circulating pipeline 4 being communicated with an outlet of the molten salt pump 3; the molten salt pump 3 and the molten salt circulating pipeline 4 cooperatively realize uniform temperature in the molten salt tank. Specifically, when the temperature measuring point arranged in the molten salt tank detects that the temperature difference of different regions of the tank body is large, the molten salt pump needs to be started to circulate the molten salt in the tank, so that the temperature of the molten salt in the tank is uniform. Moreover, the molten salt circulating pipeline 4 is arranged non-horizontally, and has a certain slope to ensure that the molten salt in the pipeline automatically flows back to the molten salt tank, and prevent the molten salt from freezing and blocking in the pipeline.

[0031] Further, the molten salt tank 1 is provided with a porous solid filler to make the temperature change uniform and stable during the heat release process of the molten salt tank, and also reduce the cost. The porous solid filler can be rock, ceramic brick, concrete and the like.

[0032] The system uses silicone heat conducting oil as an intermediate heat transfer medium, which has good thermal stability, does not scale at high temperature, and has a low freezing point (the freezing point is lower than -40℃, and the working temperature range can cover -30℃ to 300℃). The silicone heat conducting oil is arranged in the oil tank, oil pump and oil-salt heat exchanger, which can ensure thermal stability.

[0033] The above-mentioned external water inlet can be heating circulating water or domestic water. That is, the second inlet of the oil-water heat exchanger in the system is communicated with the heating circulating water or the domestic water supply. Preferably, the oil-water heat exchanger includes a first oil-water heat exchanger 9 and a second oil-water heat exchanger 10, wherein the first inlet of the first oil-water heat exchanger 9 and the first inlet of the second oil-water heat exchanger 10 are communicated with the second outlet of the oil-salt heat exchanger 6;

[0034] The first outlet of the first oil-water heat exchanger 9 and the first outlet of the second oil-water heat exchanger 10 are communicated with the oil tank 8;

[0035] The second inlet of the first oil-water heat exchanger 9 is connected to the heating cycle water inlet, and the second outlet is connected to the heating cycle water supply; the second inlet of the second oil-water heat exchanger 10 is connected to the domestic water supply, and the second outlet is connected to the domestic water supply.

[0036] Further, the molten salt energy storage heating system further comprises a hot water boiler 11, the inlet of the hot water boiler 11 is connected to the heating return water, and the outlet of the hot water boiler 11 is connected to the heating water supply. The hot water boiler 11 directly heats the heating cycle water during the valley electricity and flat electricity period, improving the operation efficiency. It can also heat the heating cycle water when the molten salt energy storage system is insufficient, improving the system operation flexibility.

[0037] In addition, the hot water boiler 11 can also be connected to the domestic water supply, and the heated water is stored in the water tank 12 for domestic hot water.

[0038] The working mode of the molten salt energy storage heating system will be introduced below:

[0039] Operation mode 1: molten salt energy storage + heating mode. During the valley electricity period, start the molten salt tank electric heater to heat the molten salt in the tank, raise the temperature of the molten salt from 190℃ to 400℃, and realize energy storage. At the same time, use the hot water boiler to heat the heating cycle water, raise the temperature of the cycle water from 40℃ to 75℃, and realize heating during this period.

[0040] Operation mode 2: molten salt heat release + heating mode. During the peak electricity period, the molten salt heat storage system releases heat, starts the oil pump and the molten salt pump, and sends the 100℃ cold oil into the oil salt heat exchanger to absorb heat, raises the temperature to 240℃, and the hot oil enters the oil water heat exchanger to heat the cycle water return. During the flat electricity period, the hot water boiler can be used to heat the heating cycle water, raising the temperature of the cycle water from 40℃ to 75℃, and realizing heating during the valley electricity period.

[0041] Operation mode 3: molten salt direct heating mode. The molten salt energy storage system stores and releases heat at the same time, after the molten salt electric heater heats the molten salt, the heat is not stored, but transferred to the silicone oil in the oil salt heat exchanger, and then the heated silicone oil is sent to the oil water heat exchanger to heat the cycle water.

[0042] Operation mode 4: molten salt circulation mode. When the temperature measuring point set in the molten salt tank detects that the temperature difference between different regions of the tank is large, the molten salt pump needs to be started to circulate the molten salt in the tank, so that the temperature of the molten salt in the tank is uniform. The molten salt circulation pipeline is provided with a certain slope to ensure that the molten salt can automatically flow back into the molten salt tank, preventing the molten salt from freezing and causing blockage in the pipeline.

[0043] Operation mode 5: molten salt heat preservation mode. When it is not in the heating season or the molten salt heat storage system is not used for a long time, the temperature in the molten salt tank needs to be maintained at about 190℃ to prevent the molten salt from freezing. When the temperature measuring point in the molten salt tank detects that the temperature is lower than 190℃, start the molten salt electric heater during the nearby valley electricity period to heat the molten salt in the tank and prevent the molten salt from freezing.

[0044] The embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments. Even if various changes are made to the present application, provided that the changes fall within the scope of the claims of the present application and equivalents thereof, they still fall within the protective scope of the present application.

Claims

1. A molten salt energy storage heating system, characterized by, It comprises: a molten salt tank, a molten salt electric heater, a molten salt pump, an oil-salt heat exchanger, an oil pump, an oil tank and an oil-water heat exchanger; the molten salt electric heater is arranged in the molten salt tank, the inlet of the molten salt pump is arranged in the molten salt tank, and the outlet of the molten salt pump is connected with the first inlet of the oil-salt heat exchanger; the second inlet of the oil-salt heat exchanger is connected with the oil tank through the oil pump, the first outlet of the oil-salt heat exchanger is connected with the molten salt tank, and the second outlet of the oil-salt heat exchanger is connected with the first inlet of the oil-water heat exchanger; the second inlet of the oil-water heat exchanger is connected with an external water inlet, the first outlet of the oil-water heat exchanger is connected with the oil tank, and the second outlet of the oil-water heat exchanger is connected with an external water supply.

2. The molten salt energy storage heating system of claim 1, wherein, The molten salt tank is also provided with a molten salt circulation pipeline, the inlet of the molten salt circulation pipeline is connected with the outlet of the molten salt pump, and the molten salt pump and the molten salt circulation pipeline cooperate to realize uniform temperature in the molten salt tank.

3. The molten salt energy storage heating system of claim 2, wherein, The molten salt circulation pipeline is arranged non-horizontally to ensure that the molten salt in the pipeline automatically flows back to the molten salt tank.

4. The molten salt energy storage heating system of claim 1, wherein, The molten salt tank is provided with a porous solid filler to make the temperature change uniform and stable during the heat release process of the molten salt tank.

5. The molten salt energy storage heating system of claim 1, wherein, Siloxane heat-conducting oil is used as the heat transfer medium in the oil-salt heat exchanger, the oil pump and the oil tank to ensure thermal stability.

6. The molten salt energy storage heating system of claim 1, wherein, The second inlet of the oil-water heat exchanger is connected with a heating circulating water or a domestic water supply.

7. The molten salt energy storage heating system of claim 1, wherein, The oil-water heat exchanger comprises a first oil-water heat exchanger and a second oil-water heat exchanger, the first inlet of the first oil-water heat exchanger and the first inlet of the second oil-water heat exchanger are connected with the second outlet of the oil-salt heat exchanger; the first outlet of the first oil-water heat exchanger and the first outlet of the second oil-water heat exchanger are connected with the oil tank; the second inlet of the first oil-water heat exchanger is connected with a heating circulating water inlet, and the second outlet of the first oil-water heat exchanger is connected with a heating circulating water supply; the second inlet of the second oil-water heat exchanger is connected with a domestic water supply, and the second outlet of the second oil-water heat exchanger is connected with a domestic water supply.

8. The molten salt energy storage heating system of claim 7, wherein, It also comprises a hot water boiler, the inlet of the hot water boiler is connected with a heating return water, and the outlet of the hot water boiler is connected with a heating water supply.

Images