Ultralow-temperature cascade cold storage device

Abstract

The invention discloses an ultralow-temperature cascade cold storage device, which belongs to the field of energy utilization and energy storage and comprises a cold quantity inlet, a porous structure, a cold flow spiral guide pipe, a first-stage cold storage structure, a partition plate I, a second-stage cold storage structure, a partition plate II, a third-stage cold storage structure, a shell, a cold quantity outlet, a hot flow inlet, a hot flow spiral guide pipe and a hot flow outlet. Through the phase change cold storage and sensible heat cold storage coupled composite energy storage system, redundant cold energy generated by gasification of liquefied natural gas in the daytime is stored in different cold storage media in a graded mode according to the temperature gradient, and cold storage and release are achieved through the refrigerant circulation system; when the gasification amount of the liquefied natural gas at night is reduced to cause insufficient cold energy supply, the cold storage device can accurately release low-temperature cold energy (-162 DEG C to-50 DEG C) and medium-temperature cold energy (-50 DEG C to 0 DEG C) stored in the cold storage device as required according to the real-time requirement of cold utilization equipment, and it is ensured that the cold energy utilization equipment can obtain stable cold energy supply under all-weather working conditions.

Description

Technical Field

[0001] The present invention relates to a cold storage device, in particular to an ultra-low temperature cascade cold storage device. Background Art

[0002] Ultra-low temperature cascaded cold storage devices are a key technology for addressing the contradiction between improving energy efficiency and electricity supply and demand. Their development stems from the needs of multiple fields: at the energy level, the difference in electricity peaks and valleys and time-of-use electricity price policies drive them to optimize grid loads by "shifting peaks and filling valleys" to reduce user costs; under environmental pressure, this technology contributes to the "dual carbon" goals by integrating renewable energy and reducing carbon emissions from traditional refrigeration systems. Existing cold storage devices mostly store cold in a single temperature range, which is prone to overcooling. Existing cold storage devices are large in size and have high site requirements. For example, a water cold storage system requires a water tank volume of hundreds of cubic meters. Summary of the Invention

[0003] The object of the present invention is to provide an ultra-low temperature cascade cold storage device to solve the problem that the existing cold storage devices are prone to overcooling.

[0004] To achieve the above objectives, the specific plan is as follows:

[0005] A super-low temperature cascade cold storage device, which consists of a cold storage part and a cold release part placed in a shell. Partition one and partition two are provided inside the shell, and the shell is divided into three cold storage structures by partition one and partition two, which are respectively a first-stage cold storage structure, a second-stage cold storage structure and a third-stage cold storage structure from top to bottom; the cold storage part consists of a cold inlet and a cold outlet symmetrically arranged at both ends of the shell and a cold flow spiral guide pipe for connecting the cold inlet and the cold outlet; the cold release part consists of a hot flow inlet and a hot flow outlet symmetrically arranged at both ends of the shell and a hot flow spiral guide pipe for connecting the hot flow inlet and the hot flow outlet; the cold flow spiral guide pipe and the hot flow spiral guide pipe pass through partition one, partition two, the first-stage cold storage structure, the second-stage cold storage structure and the third-stage cold storage structure respectively.

[0006] Furthermore, the cold flow inlet and the hot flow outlet are placed at the same end of the shell, and the cold flow outlet and the hot flow inlet are placed at the same end of the shell.

[0007] Furthermore, the primary cold storage structure, the secondary cold storage structure and the tertiary cold storage structure are made of porous medium phase change materials, and a porous skeleton structure is adopted inside them.

[0008] Furthermore, the temperature adaptation range of the first-stage cold storage structure is -160℃~-100℃, and it is made of metal-based composite phase change material; the temperature adaptation range of the second-stage cold storage structure is -80℃~-50℃, and it is made of alkane phase change cold storage material; the temperature adaptation range of the third-stage cold storage structure is -50~0℃, and it is made of water and salt phase change material.

[0009] Furthermore, the number of spiral turns of the spiral guide tube in the first-stage cold storage structure, the second-stage cold storage device and the third-stage cold storage device gradually decreases.

[0010] Furthermore, the partition plate 1 and the partition plate 2 are fixed inside the shell by welding.

[0011] Furthermore, the partition plate 1 and the partition plate 2 are made of high-strength and corrosion-resistant stainless steel or aluminum alloy, and a layer of heat-insulating coating is added on the surface.

[0012] In summary, the present invention has the following beneficial effects compared to the prior art:

[0013] In order to solve the problem of fluctuations in the amount of cold energy released due to fluctuations in the amount of LNG vaporization, the present invention designs this ultra-low temperature cascade cold storage device. By collecting the surplus cold energy generated during the gasification process of liquefied natural gas (LNG) during the day for hierarchical storage, and releasing the cold energy to the cold energy utilization system on demand during the low gas consumption period at night. Its core advantage is that it adopts a multi-stage phase change material and a spiral guide tube coupling structure to achieve gradient storage and precise release of cold energy in a wide temperature range of -160°C to -50°C, which will greatly improve the utilization rate of cold energy; through the spatiotemporal transfer of cold energy, the excess cold energy during the day can be used for nighttime use, reducing the waste rate of LNG vaporization cold energy during the day, and avoiding the loss of a large amount of energy due to frequent start and stop of cold energy utilization equipment; the cold storage unit adopts a standardized module design, supports parallel expansion and independent maintenance, and is suitable for scenarios such as distributed energy stations and port LNG receiving stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0015] Figure 1 A schematic diagram of the overall structure of an ultra-low temperature cascade cold storage device provided by the present invention;

[0016] Figure 2 This is a top view of an ultra-low temperature cascade cold storage device provided by the present invention.

[0017] The above drawings include the following reference numerals:

[0018] 1. Cold inlet; 2. Partition 1; 3. Secondary cold storage structure; 4. Shell; 5. Cold outlet; 6. Heat outlet; 7. Porous structure; 8. Primary cold storage structure; 9. Partition 2; 10. Tertiary cold storage structure; 11. Heat inlet; 12. Cold flow spiral guide tube; 13. Heat flow spiral guide tube. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form can also include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0021] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorized specification. In all examples shown and discussed herein, any specific values should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0022] See also Figures 1 to 2 As shown, the present invention provides an ultra-low temperature cascade cold storage device, which consists of a cold storage part and a cold release part placed in the same shell 4. A partition 1 2 and a partition 2 9 are provided inside the shell 4. The partition 1 2 and the partition 2 9 divide the inside of the shell 4 into three cold storage structures, which are, from top to bottom, a first-level cold storage structure 8, a second-level cold storage structure 3 and a third-level cold storage structure 10, thereby achieving the purpose of cascade cold storage.

[0023] The cold storage section comprises a cold inlet 1 and a cold outlet 5 symmetrically arranged at either end of the shell 4, along with a cold flow spiral conduit 12 connecting the cold inlet 1 and the cold flow outlet 5. The cold release section comprises a hot flow inlet 11 and a hot flow outlet 6 symmetrically arranged at either end of the shell 4, along with a hot flow spiral conduit 13 connecting the hot flow inlet 11 and the hot flow outlet 6. The cold inlet 1 and the hot flow outlet 6 are located at the same end of the shell 4, while the cold outlet 5 and the hot flow inlet 11 are located at the same end of the shell 4. The cold flow spiral conduit 12 and the hot flow spiral conduit 13 respectively pass through partition 1 2, partition 2 9, the primary cold storage structure 8, the secondary cold storage structure 3, and the tertiary cold storage structure 10. The cold flow spiral conduit 12 is used to store external cold energy in the cascade cold storage device, while the hot flow spiral conduit 13 releases cold energy through the circulating working fluid to a cold energy utilization device, such as a cold energy generator set, a low-temperature cold storage, or an air separation unit.

[0024] In actual use, the primary cold storage structure 8, the secondary cold storage structure 3, and the tertiary cold storage structure 10 store the cold energy passing through the cold flow spiral guide tube 12 in a step-by-step manner. After the primary cold storage structure 8 stores the cold energy for the first time, the secondary cold storage structure 3 stores the remaining cold energy after passing through the primary cold storage structure 8; the tertiary cold storage structure 10 stores the remaining cold energy.

[0025] The cold storage section is used to store excess cold energy in the cold storage device in a cascaded manner during the day, while the cold release section releases the cold energy stored during the day at night for use in the cold energy utilization device; the cold storage section and the cold release section are connected to form a circuit. In other words, cold energy enters the cascade cold storage device through the cold energy inlet 1 and is stored in the primary cold storage structure 8, the secondary cold storage structure 3, and the tertiary cold storage structure 10 through the cold flow spiral guide tube 12. The hot flow inlet 11 is the entrance channel for the circulating working fluid to carry cold energy out of the cold storage device at night. At night, the cold energy in the cascade cold storage device is released to external cold energy utilization equipment through the hot flow spiral guide tube 13.

[0026] The cascaded cold storage structure achieves efficient cold storage and release through the collaborative design of porous media and phase change materials (PCM). The high thermal conductivity of the porous skeleton is utilized to construct a heat transfer network, improving internal heat conduction efficiency. The pore structure also increases the contact area between the PCM and the heat transfer medium.

[0027] As a preferred embodiment, the multi-stage cold storage structure inside the cold storage device is combined with a phase change material through a porous medium. Different phase change materials are used according to different temperature ranges. The temperature range of the first-stage cold storage structure 8 is between -160 and -100°C, and a porous skeleton is used inside it and filled with metal-based composite phase change materials; the temperature range of the second-stage cold storage structure 3 is between -80 and -50°C, and for example, alkane phase change cold storage materials can be used; the temperature range of the third-stage cold storage structure 10 is between -50 and 0°C, and for example, water and salt phase change materials can be used.

[0028] As a preferred embodiment, the spiral guide tubes are distributed differently in the various levels of cold storage structures. In the first-level cold storage structure 8, the spiral guide tubes have the largest number of turns, which are in full contact with the internal porous structure 7 and the phase change material, so that the overall cold storage effect is better. The number of turns of the spiral guide tubes in the second-level cold storage device and the third-level cold storage device gradually decreases, and the cold energy stored in each level also gradually decreases.

[0029] As a preferred embodiment, the shell 4 encapsulates the entire cold storage structure and the cold storage material, and the internal partition is welded inside the shell 4.

[0030] As a preferred embodiment, partition 1 2 and partition 2 9 are made of high-strength and corrosion-resistant stainless steel or aluminum alloy, and a layer of insulating coating is added to their surfaces to achieve the division of the space of the shell 4 (i.e., the division of the primary cold storage structure 8, the secondary cold storage structure 3 and the tertiary cold storage structure 10) and ensure that there is no temperature exchange between the primary cold storage structure 8, the secondary cold storage structure 3 and the tertiary cold storage structure 10, which would lead to the problem of storage temperature loss.

[0031] Example:

[0032] like Figure 1-2As shown, an ultra-low temperature cascade cold storage device can be constructed from an austenitic stainless steel shell. Its excellent low-temperature toughness, corrosion resistance, and weldability ensure stable operation in extreme environments. Two welded partitions are distributed within the shell 4, dividing the space into three temperature gradient cold storage zones, forming a stepped energy storage structure. During daytime operation, liquefied natural gas (LNG) at -162°C enters the device through the cold inlet 1 and flows through the primary, secondary, and tertiary cold storage structures 10 along the cold flow spiral guide tube 12. The guide tube can be made of high thermal conductivity oxygen-free copper and undergo corrosion protection treatment, which can efficiently transfer cold energy to each layer of cold storage medium (such as phase change material or composite adsorbent). The LNG that has completed cold energy storage is finally discharged through the cold energy outlet 5. At night, when the LNG vaporization cold energy is insufficient, a low-temperature circulating medium is injected through the hot flow inlet 11, flows in reverse along the hot flow spiral guide tube 13 through the cold storage structure, absorbs the stored cold energy, and is then transported to the cold energy utilization equipment through the hot flow outlet 6. The device uses a three-level temperature gradient design to accurately match different cold energy requirements. The cold and hot flow guide tubes are independently arranged to avoid energy interference. The stainless steel shell 4 and the copper flow channel use transition welding technology to achieve complementary material properties. Combined with the automatic switching function of storage / release cold mode, the storage density and release controllability of ultra-low temperature cold energy are significantly improved.

[0033] Among them, the shell, partition 1 2 and partition 2 9 of the ultra-low temperature cascade cold storage device are all equipped with precision through-holes of uniform size for the arrangement of cold flow and hot flow spiral guide tubes 13. The aperture can be processed by laser cutting or CNC water jet technology to ensure that the holes between the three-level structures are strictly concentrically aligned, providing a continuous installation channel for the spiral guide tube. When the guide tube passes through the hole, a double sealing design of low-temperature sealing rubber ring and metal compensation ring is adopted to prevent cold leakage and absorb the deformation stress of the material caused by temperature difference. This coaxial aperture design enables the cold and hot flow channels to form parallel and independent paths within the three-level cold storage area, avoiding energy loss caused by fluid disturbance, while maintaining the gradient stability of each temperature level. This structural feature works synergistically with the shell material selection and partition welding and fixing process to further enhance the sealing and structural reliability of the device under extreme cold and hot cycle conditions.

[0034] The cold and hot flow spiral conduits 13 in the primary cold storage structure 8 have more turns than in the other cold storage structures. The primary cold storage structure 8 has a cold storage range of approximately -160°C, which facilitates cold storage and release. The number of turns in the conduits in the secondary cold storage structure 3 and the tertiary cold storage structure 10 decreases gradually. The ultra-low temperature cascade cold storage device achieves efficient energy management through differentiated spiral conduit designs. The cold and hot flow spiral conduits 13 in the primary cold storage structure 8 employ a densely coiled layout, with more turns than in the secondary and tertiary structures, corresponding to the core low-temperature range of -160°C. This extends the contact path between the working fluid and the phase-change cold storage medium, enhancing the efficiency of cold energy storage and release at extremely low temperatures. The number of spiral turns of the guide tubes of the secondary cold storage structure 3 (-120℃~-80℃) and the tertiary cold storage structure 10 (-50℃~-20℃) decreases step by step, which not only matches the energy density characteristics of different temperature zones, but also improves the dynamic response rate of medium and low temperature cold energy by shortening the flow channel length. All guide tubes pass through the precision through-holes of the shell and partition in a coaxial manner, combined with low-temperature elastic seals and deformation compensation components to ensure the sealing and thermal stress adaptation between the multi-stage structures. The gradient design of "high-density coiling in the deep cold zone and gradually sparse distribution in the shallow cold zone" is adopted, and the synergistic effect of the cold storage medium in the three temperature zones is combined to achieve a balance between the cold energy absorption efficiency and release flexibility.

[0035] The core of the ultra-low temperature cascade cold storage device is a porous metal skeleton structure, designed to ensure thermal conductivity and structural strength. The skeleton is made of highly thermally conductive materials such as copper or aluminum alloy, and is precision-machined to form a through-type three-dimensional pore network, significantly increasing the contact area with the cold storage medium (such as phase change materials or composite adsorbents). The porous skeleton is arranged in a gradient within each cold storage unit - the skeleton pores in the low-temperature zone are fine and dense to enhance microscopic heat transfer, while the pores in the medium and high temperature zones gradually expand to balance flow resistance and heat transfer efficiency. The copper-based skeleton is enhanced with corrosion resistance through surface plating, while the aluminum-based skeleton adopts a topological optimization design to achieve lightweighting. This porous structure7 works synergistically with the spiral guide tube to accelerate the diffusion rate of cold energy from the working fluid to the cold storage medium, and suppress the uneven flow of the liquid working fluid through the capillary action of the pores, significantly improving the energy storage density and energy scheduling response speed, making it suitable for the efficient storage and precise release of cold energy in extremely low temperature environments.

[0036] The multi-stage cold storage structure utilizes a layered design, with the phase-change cold storage materials within each unit precisely matched to their operating temperature range. This targeted configuration effectively improves the system's cold storage efficiency, allowing materials with different phase change points to store and release latent heat within their respective temperature ranges, thereby increasing energy utilization.

[0037] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0038] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An ultra-low temperature cascade cold storage device, characterized in that: It is composed of a cold storage part and a cold release part placed in a shell (4); a partition plate 1 (2) and a partition plate 2 (9) are provided inside the shell (4); the shell (4) includes three cold storage structures through the partition plate 1 (2) and the partition plate 2 (9), which are respectively a first-stage cold storage structure (8), a second-stage cold storage structure (3) and a third-stage cold storage structure (10) from top to bottom; the cold storage part is composed of a cold inlet (1) and a cold outlet (5) symmetrically arranged at both ends of the shell (4) and a cold outlet for connecting the cold inlet (1) and the cold outlet The invention relates to a heat release part, wherein the heat release part comprises a heat flow inlet (11) and a heat flow outlet (6) symmetrically arranged at both ends of the shell (4), and a heat flow spiral guide pipe (13) for connecting the heat flow inlet (11) and the heat flow outlet (6); the cold flow spiral guide pipe (12) and the hot flow spiral guide pipe (13) respectively pass through the partition plate 1 (2), the partition plate 2 (9), the first-level cold storage structure (8), the second-level cold storage structure (3) and the third-level cold storage structure (10).

2. The ultra-low temperature cascade cold storage device according to claim 1, characterized in that: The cold inlet (1) and the hot flow outlet (6) are placed at the same end of the shell (4), and the cold outlet (5) and the hot flow inlet (11) are placed at the same end of the shell (4).

3. The ultra-low temperature cascade cold storage device according to claim 1, characterized in that: The primary cold storage structure (8), the secondary cold storage structure (3) and the tertiary cold storage structure (10) are made of porous medium phase change material, and a porous skeleton structure is used inside.

4. The ultra-low temperature cascade cold storage device according to claim 3, characterized in that: The temperature adaptation range of the primary cold storage structure (8) is -160°C to -100°C, and it is made of a metal-based composite phase change material; the temperature adaptation range of the secondary cold storage structure (3) is -80°C to -50°C, and it is made of an alkane phase change cold storage material; the temperature adaptation range of the tertiary cold storage structure (10) is -50°C to 0°C, and it is made of a water and salt phase change material.

5. The ultra-low temperature cascade cold storage device according to any one of claims 1 to 4, characterized in that: The number of spiral turns of the spiral guide pipe in the first-stage cold storage structure (8), the second-stage cold storage device, and the third-stage cold storage device gradually decreases.

6. The ultra-low temperature cascade cold storage device according to claim 5, characterized in that: The partition plate 1 (2) and the partition plate 2 (9) are fixed inside the shell (4) by welding.

7. The ultra-low temperature cascade cold storage device according to claim 6, characterized in that: The partition plate 1 (2) and the partition plate 2 (9) are made of high-strength and corrosion-resistant stainless steel or aluminum alloy, and a layer of heat-insulating coating is added on the surface.

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