Energy storage type cascade cold source preparation method

Abstract

The invention relates to the technical field of energy storage liquid cooling, in particular to an energy storage type cascade cold source preparation method. Comprising a low-grade cold source, a middle-grade cold source and a high-grade cold source which are communicated with a cold needing end in a heat exchange mode. Wherein the temperatures of the secondary refrigerants provided by the low-grade cold source, the medium-grade cold source and the high-grade cold source are sequentially reduced. According to the process cold use requirement, cold source steps are reasonably divided, the cold supply capacity ratio of the low-grade cold source and the middle-grade cold source is increased, the cold supply capacity ratio of the high-grade cold source is reduced, energy consumption can be greatly reduced, and the operation cost is saved. The peak-valley electricity price difference is utilized, eutectic salt cold storage is adopted for a high-grade cold source with the highest energy consumption, eutectic salt solidification cold storage is carried out in the electricity price off-peak period, eutectic salt melting cold taking is carried out in the electricity price peak period, the effects of electricity charge saving and peak load shifting for power grid balancing are achieved, and good economic benefits and social benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of energy storage liquid cooling technology, and in particular to a method for producing an energy storage-type cascade cold source. Background Technology

[0002] In chemical production, many processes require cooling sources, such as condensation, cold deposition, crystallization, and exothermic reactions. Therefore, refrigeration plants are essential facilities for chemical production enterprises, providing cooling for these processes. Survey data shows that the electricity costs of refrigeration plants account for more than one-third of the total electricity costs of the entire plant, making them a significant energy consumer in chemical enterprises. The energy efficiency of refrigeration plants in producing cold sources significantly impacts production costs and has a substantial influence on enterprise profitability. Previously, multiple processes often required multiple reactors, and the materials within these reactors needed to be transferred between them, which not only required a large floor space but also significantly increased safety risks.

[0003] In recent years, with the increasing demands for process intensification, efficiency, and greening in the chemical industry, completing multiple processes within a single reactor has become a trend. Currently, there is an urgent need to design a cascaded cold source capable of handling cooling tasks within a corresponding temperature range while being energy-efficient, in order to minimize the electricity costs of refrigeration plant operation. Summary of the Invention

[0004] The purpose of this invention is to provide a method for generating energy storage-type cascaded cold sources, which solves the problem of high electricity costs in generating cold sources that undertake the task of cooling corresponding temperature ranges in conventional technologies.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a method for producing an energy storage-type cascaded cold source, including a low-grade cold source, a medium-grade cold source, and a high-grade cold source connected to the cooling end via heat exchange; wherein the temperature of the refrigerant provided by the low-grade cold source, the medium-grade cold source, and the high-grade cold source decreases sequentially.

[0006] In this embodiment, the high-grade cold source further includes a eutectic salt cold storage tank, a refrigerant intermediate tank, a low-temperature return tank, a low-temperature supply tank, a low-temperature refrigerator, and an open cooling tower; wherein the low-temperature supply tank supplies refrigerant to the cooling end through a low-temperature external pump and a high-grade refrigerant input pipe, and the refrigerant, after heat exchange, is connected to the low-temperature return tank through a high-grade refrigerant return pipe; The outlet of the eutectic salt cold storage tank is connected to the intermediate refrigerant tank and the cryogenic supply tank via a cold storage / cooling supply pipe, and an electrically controlled valve is installed at the inlet of the intermediate refrigerant tank and the cryogenic supply tank, respectively. The inlet of the eutectic salt cold storage tank is connected to one end of the cryogenic refrigerator via a connecting pipe, and the intermediate refrigerant tank is connected to the other end of the cryogenic refrigerator via a cold storage / cooling return pipe and a cold storage / cooling pump, and an electrically controlled valve is installed on the cold storage / cooling return pipe. The condensation heat of the cryogenic refrigerator is carried away by a cooling water system consisting of an open cooling tower and a cooling water pump.

[0007] Furthermore in this embodiment, the intermediate tank for the refrigerant is also connected to the inlet end of the eutectic salt cold storage tank through a cold storage / cold extraction return pipe, a conversion pipe, and a connecting pipe, and is provided with conveying power by the cold storage / cold extraction pump. Electrically controlled valves are installed on the connecting pipe and the conversion pipe.

[0008] Furthermore in this embodiment, the cryogenic return tank is also connected to one end of the cryogenic refrigerator via a direct cooling return pipe, and the other end of the cryogenic refrigerator is connected to the cryogenic supply tank via a direct cooling supply pipe. An electrically controlled valve and a cryogenic circulation pump are installed on the direct cooling return pipe, and an electrically controlled valve is installed on the direct cooling supply pipe.

[0009] Furthermore in this embodiment, the outlet of the cryogenic return tank is also connected to the intermediate refrigerant tank via a conduit equipped with an electrically controlled valve.

[0010] In this embodiment, the medium-grade cold source further includes a medium-temperature return liquid tank, a medium-temperature supply liquid tank connected to the medium-temperature return liquid tank, a medium-temperature chiller connected to the medium-temperature supply liquid tank, and an open cooling tower; wherein the medium-temperature supply liquid tank supplies medium-grade refrigerant to the cooling end through a medium-grade refrigerant input pipe and a medium-temperature external pump, and the cooling end is connected to the medium-temperature return liquid tank through a medium-grade refrigerant return pipe; wherein the liquid outlet of the medium-temperature return liquid tank is connected to the medium-temperature chiller through a medium-temperature circulating pump and a conduit, and the liquid outlet of the medium-temperature chiller is connected to the medium-temperature supply liquid tank.

[0011] Furthermore in this embodiment, the condensation heat of the medium-temperature chiller is carried away by a cooling water system consisting of an open cooling tower and a cooling water pump.

[0012] In this embodiment, the low-grade cold source further includes a room-temperature supply tank, a room-temperature return tank connected to the room-temperature supply tank, and a closed-loop cooling tower for cooling the low-grade refrigerant in the room-temperature supply tank. The room-temperature supply tank supplies low-grade refrigerant to the cooling end via a low-grade refrigerant inlet pipe and a room-temperature external pump. The cooling end is also connected to the room-temperature return tank via a low-grade refrigerant return pipe. The room-temperature return tank is connected to the closed-loop cooling tower via a delivery pipe and a room-temperature circulating pump. The outlet of the closed-loop cooling tower is also connected to the room-temperature supply tank via a conduit.

[0013] Furthermore in this embodiment, the cold end is a reactor with a heat exchange jacket, and a temperature sensor is installed inside the reactor.

[0014] Furthermore in this embodiment, the inlet and outlet of the reactor jacket are connected to the supply and return liquid manifolds respectively via a conduit. The supply and return liquid manifolds are connected to the main supply and return liquid manifolds of the three grades of refrigerant via branch pipes. An electric valve is installed on the branch pipe to realize the cascade cooling of the three grades of refrigerant to the reactor jacket.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention provides a method for producing an energy storage-type cascaded cold source, which is applicable to cascaded cooling scenarios in the chemical industry and has significant energy-saving benefits compared to traditional methods.

[0016] This invention is suitable for chemical enterprises with high process cooling requirements, where this method will generate significant benefits. By rationally dividing the cooling source into stages according to process cooling requirements, increasing the proportion of cooling capacity supplied by low-grade and medium-grade cooling sources, and reducing the proportion of cooling capacity supplied by high-grade cooling sources, energy consumption can be significantly reduced, and operating costs saved. Using a single refrigerant as the carrier for all three cooling sources is well-suited to the tiered cooling methods of end users, such as reactor jackets. Utilizing the peak-valley electricity price difference, eutectic salt is used for cold storage of the highest-energy-consuming high-grade cooling source. Eutectic salt is solidified and stored during periods of low electricity prices, while melting and cooling are performed during periods of high electricity prices. This achieves both electricity cost savings and peak-shifting for grid balance, resulting in good economic and social benefits. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a system flowchart of the energy storage-type cascade cold source production method of the present invention; Figure 2 for Figure 1 Schematic diagram of medium-to-high grade low-temperature cold source; Figure 3 for Figure 1 Schematic diagram of a medium-grade, medium-temperature cold source; Figure 4 for Figure 1 Schematic diagram of a medium-to-low grade ambient temperature cold source.

[0019] Explanation of reference numerals in the attached diagram: 11. Eutectic salt cold storage tank; 111. Cold storage / cooling supply pipe; 112. Connecting pipe; 113. Transfer pipe; 12. Intermediate refrigerant tank; 121. Cold storage / cooling return pipe; 13. Cryogenic return tank; 131. High-grade refrigerant return pipe; 132. Direct cooling return pipe; 14. Cryogenic supply tank; 141. High-grade refrigerant input pipe; 142. Direct cooling supply pipe; 15. Cryogenic circulation pump; 16. Cold storage / cooling pump; 17. Cryogenic external pump. 18. Low-temperature refrigeration unit; 21. Medium-temperature return tank; 211. Medium-grade refrigerant return pipe; 22. Medium-temperature supply tank; 221. Medium-grade refrigerant inlet pipe; 23. Medium-temperature circulating pump; 24. Medium-temperature refrigeration unit; 25. Medium-temperature external supply pump; 31. Normal-temperature supply tank; 311. Low-grade refrigerant inlet pipe; 32. Normal-temperature return tank; 321. Low-grade refrigerant return pipe; 33. Normal-temperature circulating pump; 34. Closed-loop cooling tower; 35. Normal-temperature external supply pump. Detailed Implementation

[0020] refer to Figure 1 As shown, this embodiment discloses a method for producing an energy storage-type cascaded cold source, including a low-grade cold source, a medium-grade cold source, and a high-grade cold source connected to the cooling end via heat exchange; wherein the temperature of the refrigerant provided by the low-grade cold source, the medium-grade cold source, and the high-grade cold source decreases sequentially.

[0021] To ensure total cooling capacity, the cold source is graded, producing three different temperature-grade cold sources: a primary cold source (low-grade, ambient temperature), a secondary cold source (medium-grade, medium-temperature), and a tertiary cold source (high-grade, low-temperature). The low- and medium-grade cold sources replace a portion of the high-grade cold source, handling cooling within their respective temperature ranges, thus significantly improving the refrigeration plant's energy efficiency. The same refrigerant is used as the carrier for all three cold sources to prevent contamination and deterioration when they alternately enter the heat exchange jacket of the same reactor, ensuring long-term stable operation of the cold source and reactor heat exchange system. In the energy-intensive tertiary cold source (low-temperature) system, a eutectic salt aqueous solution energy storage device is installed. Utilizing the eutectic salt aqueous solution's defined low-temperature freezing point at its eutectic concentration, phase change energy storage is achieved, minimizing or eliminating the use of expensive peak electricity, thereby significantly reducing electricity costs for cold source production.

[0022] Specifically as follows: The primary cold source is a room temperature cold source, which uses a closed cooling tower to produce room temperature refrigerant. The cold source is obtained through heat exchange between the closed cooling tower and the atmosphere. This process does no work, only heat exchange, so the comprehensive energy efficiency ratio can reach 20, which has very significant energy-saving benefits.

[0023] The secondary cold source is a medium-temperature cold source, which uses a medium-temperature refrigeration mechanism to obtain a medium-temperature refrigerant. Essentially, this method obtains the cold source by the compressor doing work and the condenser exchanging heat. This process requires the compressor to do work, so the overall energy efficiency ratio will be lower than that of the primary cold source. However, because the evaporation temperature is higher (medium temperature), the overall energy efficiency ratio can be close to 5, which has significant energy-saving benefits.

[0024] The tertiary cold source is a low-temperature cold source, employing a low-temperature refrigeration mechanism to obtain a low-temperature refrigerant. This method also obtains the cold source through compressor work and condenser heat exchange, but because the evaporation temperature is low—even lower than that of the secondary cold source—its overall energy efficiency ratio generally does not exceed 3. Due to the low overall energy efficiency ratio of the tertiary cold source, the electricity consumption per unit of cooling capacity is also the highest. To reduce electricity costs, a eutectic salt aqueous solution phase change energy storage device is installed. During off-peak hours when electricity prices are low, the refrigeration mechanism is turned on to cool the eutectic salt aqueous solution, causing it to solidify from liquid to solid, storing the cooling capacity. During peak hours when electricity prices are high, the refrigeration mechanism is not turned on or is used less frequently, utilizing the cooling capacity released when the eutectic salt aqueous solution melts from solid to liquid to provide external cooling. This process allows for less or no operation of the refrigeration mechanism during peak hours, significantly reducing the electricity costs of producing the low-temperature cold source.

[0025] In practical implementation, the system of this invention is designed with a tiered cold source, with each 25°C increment representing a stage. Specifically, it is designed with a -15°C low-temperature cold source, a +10°C medium-temperature cold source, and a +35°C ambient-temperature cold source to achieve tiered cooling of the reactor. The four parts are described in detail below: refer to Figure 2 In this embodiment, the high-grade cold source includes a eutectic salt storage tank 11, a refrigerant intermediate tank 12, a low-temperature return tank 13, a low-temperature supply tank 14, a low-temperature refrigerator 18, and an open cooling tower; wherein the low-temperature supply tank 14 delivers refrigerant to the cooling end through a low-temperature external pump 17 and a high-grade refrigerant input pipe 141, and the refrigerant, after heat exchange, is connected to the low-temperature return tank 13 through a high-grade refrigerant return pipe 131.

[0026] The outlet of the eutectic salt storage tank 11 is connected to the intermediate refrigerant tank 12 and the cryogenic supply tank 14 via a storage and cooling supply pipe 111, and an electric control valve (M-4 and M-3) is installed at the inlet of the intermediate refrigerant tank 12 and the cryogenic supply tank 14, respectively. The inlet of the eutectic salt storage tank 11 is connected to one end of the cryogenic refrigerator 18 via a connecting pipe 112. The intermediate refrigerant tank 12 is connected to the other end of the cryogenic refrigerator 18 via a storage and cooling return pipe 121 and a storage / cooling pump 16, and an electric control valve (M-7) is installed on the storage and cooling return pipe 121. The condensation heat of the cryogenic refrigerator (18) is carried away by a cooling water system consisting of an open cooling tower and a cooling water pump.

[0027] The intermediate tank 12 of the refrigerant is also connected to the inlet end of the eutectic salt storage tank 11 through the storage and extraction return liquid pipe 121, the conversion pipe 113 and the connecting pipe 112, and is provided with conveying power by the storage / extraction pump 16. Electrically controlled valves (M-2 and M-8) are installed on the connecting pipe 112 and the conversion pipe 113.

[0028] The cryogenic return tank 13 is connected to one end of the cryogenic refrigerator 18 via a direct cooling return pipe 132, and the other end of the cryogenic refrigerator 18 is connected to the cryogenic supply tank 14 via a direct cooling supply pipe 142. An electric control valve (M-9) and a cryogenic circulation pump 15 are installed on the direct cooling return pipe 132, and an electric control valve (M-1) is installed on the direct cooling supply pipe (142).

[0029] The outlet of the cryogenic return tank 13 is also connected to the intermediate refrigerant tank 12 via a conduit with an electrically controlled valve (M-5).

[0030] The aforementioned electrically controlled valves (M-1, 2, 3, 4, 5, 7, 8, 9) are all controlled and adjusted by a PLC control system based on the needs of the cooling end, specifically through temperature sensors.

[0031] High-grade cold source: Composed of a cryogenic refrigerator, eutectic salt cold storage tank, intermediate tank for cold storage (extraction) refrigerant, -10℃ return tank, -15℃ supply tank, cold storage / extraction pump, cryogenic circulating pump, cryogenic external supply pump, open cooling tower, and cooling water pump. It offers four refrigeration modes and one external cooling supply mode. 1) Eutectic salt solidification and cold storage: The cold storage / cooling pump is turned on, and the cryogenic refrigerator is in cold storage mode. The temperature of the refrigerant entering and leaving the eutectic salt cold storage tank is -25℃ and -20℃, respectively. This temperature is lower than the freezing point of the eutectic salt aqueous solution, which causes the eutectic salt in the eutectic salt cold storage tank to solidify and store cold. The refrigerant circulates between the cold storage (cooling) refrigerant intermediate tank, the cryogenic refrigerator, and the eutectic salt cold storage tank. 2) Eutectic Salt Melting and Cooling: When the cold storage / cooling pump is activated, the eutectic salt in the cold storage tank melts and cools. The refrigerant entering and exiting the eutectic salt cold storage tank reaches temperatures of -10℃ and -15℃, respectively. These temperatures are higher than the freezing point of the magnesium chloride aqueous solution, facilitating the melting and cooling of the eutectic salt in the cold storage tank. The refrigerant circulates between the -10℃ return tank, the intermediate cold storage (cooling) refrigerant tank, the eutectic salt cold storage tank, and the -15℃ supply tank. 3) Direct cooling of cryogenic refrigerator: The cryogenic circulation pump is turned on, the cryogenic refrigerator is in refrigeration mode, the temperature of the refrigerant entering and leaving the cryogenic refrigerator is -10℃ and -15℃, and the refrigerant circulates between the -10℃ return tank, the cryogenic refrigerator, and the -15℃ supply tank. 4) Cryogenic Refrigeration Direct Cooling + Eutectic Salt Melting for Cooling: The cryogenic circulation pump is turned on, and the cryogenic refrigeration unit operates in refrigeration mode. The refrigerant entering and exiting the cryogenic refrigeration unit is at -10℃ and -15℃, respectively. Simultaneously, the cold storage / cooling pump is turned on, and the eutectic salt in the eutectic salt cold storage tank melts for cooling. The refrigerant entering and exiting the eutectic salt cold storage tank is at -10℃ and -15℃, respectively. This temperature is higher than the freezing point of magnesium chloride aqueous solution, causing the eutectic salt in the eutectic salt cold storage tank to melt for cooling. The refrigerant circulates in the loops described in points 2 and 3 above.

[0032] The valve status related to the above four working modes is shown in Table 1.

[0033] Table 1 Valve Status Table for Various Operating Conditions of Low-Temperature Cold Source Example: Introduction to Cold Storage Tanks A coil-type cold storage system is employed. A refrigerant coil is placed inside the cold storage tank, which contains an aqueous solution of a eutectic salt (magnesium chloride aqueous solution, 25% mass concentration, freezing point -19.4℃, latent heat of phase change 223.1 KJ / KG). During cold storage, the refrigerant inlet temperature is -25℃, below its freezing point. Therefore, the refrigerant flows within the metal coil, releasing cold energy, causing the eutectic salt aqueous solution outside the metal coil to cool and condense into a solid state. Simultaneously, the refrigerant temperature rises to -20℃ and returns to the refrigeration unit. During cold extraction, the refrigerant inlet temperature is -10℃, above its freezing point. Therefore, the refrigerant flows within the metal coil, releasing heat, causing the solid eutectic salt outside the metal coil to heat and melt into a liquid state. Simultaneously, the refrigerant temperature drops to -15℃, becoming a low-temperature cold source.

[0034] 5) In the external cooling mode, the low-temperature external pump draws in the refrigerant from the -15℃ supply tank at a low position, delivers it to the user end, and returns it to the -10℃ return tank after heat exchange.

[0035] refer to Figure 3The medium-grade cold source includes a medium-temperature return tank 21, a medium-temperature supply tank 22 connected to the medium-temperature return tank 21, a medium-temperature chiller 24 connected to the medium-temperature supply tank 22, and an open cooling tower. The medium-temperature supply tank 22 supplies medium-grade refrigerant to the cooling end via a medium-grade refrigerant inlet pipe 221 and a medium-temperature external pump 25. The cooling end is connected to the medium-temperature return tank 21 via a medium-grade refrigerant return pipe 211. The outlet of the medium-temperature return tank 21 is connected to the medium-temperature chiller 24 via a medium-temperature circulating pump 23 and a conduit. The outlet of the medium-temperature chiller 24 is connected to the medium-temperature supply tank 22. The condensation heat of the medium-temperature chiller 24 is removed by a cooling water system consisting of an open cooling tower and a cooling water pump.

[0036] The medium-grade cold source consists of a medium-temperature chiller, a +10℃ supply tank, a +15℃ return tank, a medium-temperature circulating pump, a medium-temperature external supply pump, an open cooling tower, and a cooling water pump. The workflow is as follows: the medium-temperature circulating pump draws refrigerant solution from the +15℃ return tank and sends it to the medium-temperature chiller. After cooling, it returns to the +10℃ supply tank. The medium-temperature external supply pump draws refrigerant solution from the +10℃ supply tank and supplies it to various reaction vessels in the workshop. After heat exchange in the reaction vessel jacket, it returns to the +15℃ return tank.

[0037] refer to Figure 4 The low-grade cold source includes a room-temperature supply tank 31, a room-temperature return tank 32 connected to the room-temperature supply tank, and a closed-loop cooling tower 34 for cooling the low-grade refrigerant in the room-temperature supply tank 31; wherein the room-temperature supply tank 31 supplies low-grade refrigerant to the interior of the cooling end through a low-grade refrigerant inlet pipe 311 and a room-temperature external pump 35, and the cooling end is also connected to the room-temperature return tank 32 through a low-grade refrigerant return pipe 321; wherein the room-temperature return tank 32 is connected to the closed-loop cooling tower 34 through a delivery pipe and a room-temperature circulating pump 33, and the outlet of the closed-loop cooling tower 34 is also connected to the room-temperature supply tank 31 through a conduit.

[0038] Low-grade cold source end: Consists of a +35℃ supply tank, a +40℃ return tank, an ambient temperature circulating pump, an ambient temperature external supply pump, and a closed-loop cooling tower. The workflow is as follows: The ambient temperature circulating pump draws refrigerant solution from the +40℃ return tank and sends it to the closed-loop cooling tower. After being cooled by heat exchange with the atmosphere in the closed-loop cooling tower, it returns to the +35℃ supply tank. The ambient temperature external supply pump draws refrigerant solution from the +35℃ supply tank and supplies it to various reaction vessels in the workshop. After heat exchange in the reaction vessel jacket, it returns to the +40℃ return tank.

[0039] In this embodiment, the low-grade, medium-grade, and high-grade refrigerants used above are all the same refrigerant, such as a 45% ethylene glycol aqueous solution. This medium has a freezing point of -30.5°C and a boiling point of 106.7°C, and can remain liquid in a temperature range of -25°C to 35°C.

[0040] In this embodiment, the cooling end is a reactor with a heat exchange jacket, and a temperature sensor is installed inside the reactor. The inlet and outlet of the reactor jacket are connected to the supply and return liquid manifolds respectively via a conduit. The supply and return liquid manifolds are connected to the main supply and return liquid manifolds of three grades of refrigerant via branch pipes. An electric valve is installed on the branch pipe to realize the cascade cooling of the three grades of refrigerant to the reactor jacket.

[0041] The reactor end consists of a room temperature cold source supply pipe, a medium temperature cold source supply pipe, a low temperature cold source supply pipe, a supply manifold, a reactor jacket supply pipe, a reactor jacket return pipe, a return manifold, and a room temperature cold source return pipe, a medium temperature cold source return pipe, and a low temperature cold source return pipe. The room temperature cold source supply pipe, the medium temperature cold source supply pipe, and the low temperature cold source supply pipe (a total of 3 pipes, each with 3 solenoid valves) are connected to the supply manifold; the room temperature cold source return pipe, the medium temperature cold source return pipe, and the low temperature cold source return pipe (a total of 3 pipes, each with 3 solenoid valves) are connected to the return manifold. One pipe at the bottom of the supply manifold connects to the reactor jacket supply pipe at the bottom of the reactor jacket, and one pipe at the bottom of the return manifold connects to the reactor jacket return pipe at the top of the reactor jacket. The working process is as follows: the temperature sensor inside the reactor controls the opening and closing of each solenoid valve, and the reactor sequentially enters the ambient temperature cold source, the medium temperature cold source, and the low temperature cold source in different temperature ranges to achieve the purpose of stepped cooling.

[0042] Application examples A chemical plant in Zhejiang Province has a reactor jacket with a total cooling capacity of approximately 3600 kW. It employs an energy storage-type tiered cold source system, with each tier representing a 25°C increment. Specifically, it is designed with a -15°C low-temperature cold source, a +10°C medium-temperature cold source, and a +35°C ambient-temperature cold source. Each tier has a designed cooling capacity of 1200 kW. Specific configuration parameters are as follows: Table 2 Low-temperature cold sources

[0043] Table 3 Medium-temperature cold source

[0044] Table 4 Normal temperature cold source

[0045] In this embodiment, the overall energy efficiency ratio (EER) of the low-temperature cold source is 2.91, that of the medium-temperature cold source is 4.68, and that of the ambient-temperature cold source is 20.87. By replacing part of the low-temperature cold source with medium-temperature and ambient-temperature cold sources, the overall energy efficiency ratio is significantly improved, resulting in significant energy-saving benefits.

[0046] 2. Benefits of electricity pricing policies According to a document issued by a certain province on January 25, 2024, and implemented on March 1, 2024, the peak-valley time periods and electricity price fluctuation ratios are as follows: Table 5. Peak and Valley Period Division

[0047] Table 6 Peak-Valley Electricity Price Fluctuation Ratio

[0048] Comparing peak, mid-peak, and off-peak electricity prices experienced by the factory during working days, the peak-to-off-peak ratio is 5.21 times in summer and winter, 4.34 times in summer and winter, and 3.67 times in spring and autumn. The significant price differences during peak, mid-peak, and off-peak periods in electricity pricing policies provide a solid policy foundation for the application of eutectic salt cold storage / extraction technology. The use of eutectic salt cold storage / extraction technology for low-temperature cold sources also provides a technical solution to the high electricity costs of conventional unit operation during working hours. By utilizing the peak-valley price difference, low-temperature cold sources use eutectic salt for cold storage during off-peak periods to transfer cooling costs during peak periods. Eutectic salt is solidified for cold storage during off-peak periods and melted for cold extraction during peak periods, achieving both economic benefits in saving electricity costs and social benefits in balancing the power grid through peak-shifting and valley-filling.

[0049] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for producing an energy storage-type cascaded cold source, characterized in that: It includes a low-grade cold source, a medium-grade cold source, and a high-grade cold source that are connected to the cooling end via heat exchange; wherein the temperature of the refrigerant provided by the low-grade cold source, the medium-grade cold source, and the high-grade cold source decreases sequentially.

2. The method for producing an energy storage-type cascade cold source according to claim 1, characterized in that: The high-grade cold source includes a eutectic salt storage tank (11), a refrigerant intermediate tank (12), a low-temperature return tank (13), a low-temperature supply tank (14), a low-temperature refrigerator (18), and an open cooling tower; wherein the low-temperature supply tank (14) delivers refrigerant to the cooling end through a low-temperature external pump (17) and a high-grade refrigerant input pipe (141), and the refrigerant, after heat exchange, is connected to the low-temperature return tank (13) through a high-grade refrigerant return pipe (131). The outlet of the eutectic salt cold storage tank (11) is connected to the intermediate tank of refrigerant (12) and the low-temperature supply tank (14) respectively through the cold storage and cold extraction supply pipe (111), and an electric control valve is provided at the inlet of the intermediate tank of refrigerant (12) and the low-temperature supply tank (14); the inlet of the eutectic salt cold storage tank (11) is connected to one end of the low-temperature refrigerator (18) through the connecting pipe (112); the intermediate tank of refrigerant (12) is connected to the other end of the low-temperature refrigerator (18) through the cold storage and cold extraction return pipe (121) and the cold storage / cold extraction pump (16), and an electric control valve is provided on the cold storage and cold extraction return pipe (121); the condensation heat of the low-temperature refrigerator (18) is carried away by the cooling water system composed of an open cooling tower and a cooling water pump.

3. The method for producing an energy storage-type cascade cold source according to claim 2, characterized in that: The intermediate tank (12) for the refrigerant is also connected to the inlet end of the eutectic salt storage tank (11) through the storage and cooling return pipe (121), the conversion pipe (113) and the connecting pipe (112), and is provided with conveying power through the storage / cooling pump (16). Electrically controlled valves are provided on the connecting pipe (112) and the conversion pipe (113).

4. The method for producing an energy storage-type cascade cold source according to claim 3, characterized in that: The cryogenic return tank (13) is also connected to one end of the cryogenic refrigerator (18) through a direct cooling return pipe (132). The other end of the cryogenic refrigerator (18) is connected to the cryogenic supply tank (14) through a direct cooling supply pipe (142). An electric control valve and a cryogenic circulation pump (15) are installed on the direct cooling return pipe (132), and an electric control valve is installed on the direct cooling supply pipe (142).

5. The method for producing an energy storage-type cascade cold source according to claim 4, characterized in that: The outlet of the cryogenic return tank (13) is also connected to the intermediate tank (12) of the refrigerant via a conduit with an electrically controlled valve (5).

6. The method for producing an energy storage-type cascade cold source according to claim 1, characterized in that: The medium-grade cold source includes a medium-temperature return liquid tank (21), a medium-temperature supply liquid tank (22) connected to the medium-temperature return liquid tank (21), a medium-temperature chiller (24) connected to the medium-temperature supply liquid tank (22), and an open cooling tower; wherein the medium-temperature supply liquid tank (22) delivers medium-grade refrigerant to the cooling end through a medium-grade refrigerant input pipe (221) and a medium-temperature external pump (25), and the cooling end is connected to the medium-temperature return liquid tank (21) through a medium-grade refrigerant return pipe (211); wherein the liquid outlet of the medium-temperature return liquid tank (21) is connected to the medium-temperature chiller (24) through a medium-temperature circulation pump (23) and a conduit, and the liquid outlet of the medium-temperature chiller (24) is connected to the medium-temperature supply liquid tank (22).

7. The method for producing an energy storage-type cascade cold source according to claim 6, characterized in that: The condensation heat of the medium-temperature refrigeration unit (24) is carried away by a cooling water system consisting of an open cooling tower and a cooling water pump.

8. The method for producing an energy storage-type cascade cold source according to claim 1, characterized in that: The low-grade cold source includes a room temperature supply tank (31), a room temperature return tank (32) connected to the room temperature supply tank, and a closed cooling tower (34) for cooling the low-grade refrigerant in the room temperature supply tank (31); wherein the room temperature supply tank (31) supplies low-grade refrigerant to the interior of the cooling end through a low-grade refrigerant inlet pipe (311) and a room temperature external pump (35), and the cooling end is also connected to the room temperature return tank (32) through a low-grade refrigerant return pipe (321); wherein the room temperature return tank (32) is connected to the closed cooling tower (34) through a delivery pipe and a room temperature circulating pump (33), and the outlet of the closed cooling tower (34) is also connected to the room temperature supply tank (31) through a conduit.

9. The method for producing an energy storage-type cascade cold source according to any one of claims 1-8, characterized in that: The cooling end is a reactor with a heat exchange jacket, and a temperature sensor is installed inside the reactor.

10. The method for producing an energy storage-type cascade cold source according to claim 9, characterized in that: The inlet and outlet of the reactor jacket are connected to the supply and return liquid manifolds respectively via a conduit. The supply and return liquid manifolds are connected to the main supply and return liquid manifolds of the three grades of refrigerant via branch pipes. An electric valve is installed on the branch pipe to realize the cascade cooling of the three grades of refrigerant to the reactor jacket.

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