A gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method

Abstract

The present invention relates to the technical field of heat storage methods and discloses a gas-liquid-solid-liquid dual-phase change direct contact phase change heat storage method, which comprises two phase change regions: a solid-liquid phase change region and a gas-liquid phase change region, and includes the following structure: a pipe box 1, a pipe box 2, a U-shaped tube, a baffle, and a phase change heat storage material PCM (solid-liquid phase change region). The solid phase change material is accelerated to melt by the combined action of boiling gas and high-temperature liquid, achieving a high heat flow phase change heat storage capacity. The present invention utilizes a dual-phase change direct contact phase change heat storage mode consisting of two phase change regions: the first phase change region is a solid-liquid phase change region, located at the lower end of the device, and is mainly composed of phase change material and liquid; the second phase change region is located at the upper end of the device and is composed of gas and liquid (this liquid is incompatible with the liquid in the solid-liquid phase change region due to the density difference).

Description

Technical Field

[0001] The present invention relates to the technical field of heat storage methods, and in particular to a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method. Background Art

[0002] Compared with the indirect phase change heat storage method, the direct contact heat storage method eliminates the need for materials and designs for the heat transfer surface. The direct mixing of the heat storage material and the heat exchange medium simplifies the internal structure, reduces the difficulty and cost of the manufacturing process of the heat storage device, and also increases the heat exchange area and space, achieving advantages such as high heat transfer efficiency, and effectively improving the efficiency of heat storage and heat release. However, the existing technical problems are: 1. The heat exchange capacity in phase change heat storage is small, and the heat storage and heat release time is long; 2. The heat storage material in the phase change heat storage device is prone to leakage risks; 3. The phase change heat storage device has a complex structure, etc. Summary of the Invention

[0003] The purpose of the present invention is to provide a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method to achieve heat exchange storage, greatly increase the heat exchange capacity of the system, thereby saving the time of charging and discharging heat and improving the efficiency of the system.

[0004] To achieve the above objectives, the present invention provides the following technical solutions: a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method, comprising two phase change regions, namely a solid-liquid phase change region and a gas-liquid phase change region, and including the following structure: a partition, a gas-liquid phase change zone, a phase change heat storage material PCM, the solid-liquid phase change region occupies the majority and is not arranged with heat exchange tubes, the gas-liquid phase change region occupies approximately 1 / 3 and is arranged with heat exchange tubes, and the tubes have various forms such as spiral coils, serpentine tubes, U-shaped tubes, etc., and are configured with a tube box; in addition to the heat absorption and heat release functions, the gas-liquid phase change region also connects the solid phase change material and the heat transfer tube, and accelerates the melting of the solid phase change material to accelerate heat absorption when in the heat storage condition.

[0005] Step 1: When the system is in heat storage:

[0006] S11, the dual-phase change direct contact phase change heat storage device is turned upside down, and the liquid in the gas-liquid phase change zone is immersed in the heat exchange tube with high-temperature fluid flowing, and the liquid is heated to boiling;

[0007] S12, the liquid in the gas-liquid phase change region is heated, boiled, and vaporized, and then impacts the phase change material in the solid-liquid phase change region, accelerating the melting of the solid phase change material, and realizing a large heat flow phase change to store heat;

[0008] Step 2: When the system is exothermic:

[0009] S21. Place the dual-phase change direct contact phase change heat storage device upright. When the solid-liquid phase change zone is a high-temperature liquid, heat storage is complete. At this time, the liquid in the gas-liquid zone contacts the high-temperature liquid in the underlying phase change zone.

[0010] S22. When the liquid in the gas-liquid zone comes into contact with high temperature, it vaporizes and rises to the heat exchange tube with cold fluid flowing there. When the high-temperature gas comes into contact with the low-temperature heat exchange tube, it condenses and falls back to the high-temperature phase change zone, transferring heat to the cold fluid. This cycle repeats to achieve large heat flow and heat release.

[0011] Preferably, the solid-liquid phase change region is where the solid phase change material is accelerated to melt by the combined action of the boiling gas and the high-temperature liquid, thereby achieving the phase change latent heat storage.

[0012] Preferably, the gas-liquid phase change region is formed by condensation heat exchange between the gas and the low-temperature fluid flowing in the pipeline.

[0013] Preferably, the solid-liquid phase change region is located at the lower end of the device and is composed of phase change material and heat-conducting liquid.

[0014] Preferably, the gas-liquid phase change region is located at the upper end of the device, and the gas-liquid phase change region is liquid, and the liquid is incompatible with the heat-conducting liquid in the solid phase change region, and there is a density difference.

[0015] The present invention provides a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method.

[0016] Beneficial effects:

[0017] (1) The present invention achieves large heat flow heat exchange because the dual-phase change direct contact heat storage is not affected by wall resistance and because there is direct contact between solid-liquid and gas-liquid dual-phase change, thereby effectively solving the problems of small heat exchange capacity and long heat storage and release time of phase change heat storage.

[0018] (2) The present invention adopts a dual-phase-change direct contact phase-change heat storage mode, which is composed of two phase-change regions: the first phase-change region is a solid-liquid phase-change region, located at the lower end of the device, and is mainly composed of phase-change materials and heat-conducting liquid; the second phase-change region is located at the upper end of the device, and is composed of gas, and its region is liquid (this liquid is incompatible with the liquid in the solid-liquid phase-change region due to the density difference). Since there are two regions for heat exchange storage, the heat exchange capacity of the system is greatly increased, thereby saving the time for charging and discharging heat. The phase-change temperature of the solid phase-change material is higher than the temperature of the liquid in the gas-liquid phase-change region, which makes it gasified and improves the efficiency of the system.

[0019] (3) The present invention is composed of two phase change regions in a cylinder, with distinct partitions, good integrity and airtightness, so that the heat storage material is not easily leaked. Furthermore, the three device modes provided by the present invention are simple in structure and easy to move, thus greatly optimizing the structural complexity and inconvenience of previous direct contact phase change heat storage.

[0020] (4) The present invention is compared with the direct contact type: when storing heat, the comparison with the general direct contact type is as follows: when the solid phase change material is stored again and turned upside down, the impact of gasification will cause the phase change material to fall and move, thereby increasing the heat exchange area, while the general direct contact solid phase change material is immobile and has a strong heat exchange effect only near the channel; when releasing heat, due to the combined effect of gas-liquid phase change and solid-liquid phase change, the overall phase change releases heat, achieving a large heat flow heat exchange; compared with the indirect type: when storing heat, the outside of the indirect tube is solid phase change material, with a large thermal resistance, and the outside of the heat transfer tube is liquid, with a small thermal resistance and a large boiling heat exchange; when releasing heat, the gasified gas in the gas-liquid zone will condense and exchange heat when it hits the cold tube, and the condensation heat exchange is phase change heat, which achieves a large heat release. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram of a U-shaped tube-type dual-phase change direct contact phase change heat storage device according to embodiment 1 of the present invention;

[0022] Figure 2 This is a diagram of a spiral tube type dual phase change direct contact phase change heat storage device according to embodiment 2 of the present invention;

[0023] Figure 3 This is a view of a serpentine tube type dual phase change direct contact phase change heat storage device according to embodiment three of the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention.

[0026] Example 1:

[0027] like Figure 1As shown, the present invention provides a technical solution: a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method, including two phase change regions, namely a solid-liquid phase change region and a gas-liquid phase change region, and including the following structures: a pipe box 1, a pipe box 2, a U-shaped tube, a partition, a phase change heat storage material PCM (solid-liquid phase change region), the solid phase change material in the solid-liquid phase change region absorbs heat and melts through a hot fluid to store phase change latent heat, the gas-liquid phase change region is a condensation heat exchanger where the gas encounters a low-temperature fluid flowing in a pipeline, the solid-liquid phase change region is located at the lower end of the device, and is composed of a phase change material and a heat-conducting liquid, the gas-liquid phase change region is located at the upper end of the device, and the gas-liquid phase change region is liquid, the liquid is incompatible with the heat-conducting liquid in the solid phase change region, and there is a density difference;

[0028] Step 1: When the system is in the heat storage phase, the lower phase change zone is solid (solidified after exothermic reaction). The device is inverted. The liquid in the gas-liquid phase change zone now immerses the heat exchange tubes, making contact with them. Simultaneously, the solid phase change material, having solidified after exothermic reaction, becomes sticky and adheres to the wall. Consequently, the fluid in the tubes heats the liquid in the gas-liquid phase change zone, causing it to boil. The boiling gas impacts the surface of the solid phase change material, accelerating its melting.

[0029] S11, the dual-phase change direct contact phase change heat storage device is turned upside down, and the liquid in the gas-liquid phase change zone is immersed in the heat exchange tube with high-temperature fluid flowing, and the liquid is heated to boiling;

[0030] S12, the liquid in the gas-liquid phase change region is heated, boiled, and vaporized, and then impacts the phase change material in the solid-liquid phase change region, accelerating the melting of the solid phase change material, and realizing a large heat flow phase change to store heat;

[0031] Step 2: When the system is in the process of heat release: when the solid-liquid phase change material is liquid (indicating that melting / heat absorption is completed), when heat release is required, since the liquid after heat absorption and melting is a high-temperature liquid, the gas-liquid phase change area will contact the high-temperature area below and there will be a vaporization process. After vaporization, it rises to the low-temperature heat exchange tube. After encountering the low-temperature tube, the high-temperature gas will condense into droplets and fall back into the solid-liquid phase change area, repeating the cycle.

[0032] S21. Place the dual-phase change direct contact phase change heat storage device upright. When the solid-liquid phase change zone is a high-temperature liquid, heat storage is complete. At this time, the liquid in the gas-liquid zone contacts the high-temperature liquid in the underlying phase change zone.

[0033] S22. When the liquid in the gas-liquid zone comes into contact with high temperature, it vaporizes and rises to the heat exchange tube with cold fluid flowing there. When the high-temperature gas comes into contact with the low-temperature heat exchange tube, it condenses and falls back to the high-temperature phase change zone, transferring heat to the cold fluid. This cycle repeats to achieve large heat flow and heat release.

[0034] Example 2:

[0035] like Figure 2 As shown, the present invention provides a technical solution: a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method, including two phase change regions, namely a solid-liquid phase change region and a gas-liquid phase change region, and including the following structures: a pipe box 1, a pipe box 2, a phase change heat storage material PCM (solid-liquid phase change region), and a spiral coil. The solid phase change material in the solid-liquid phase change region absorbs heat and melts through a hot fluid to store phase change latent heat. The gas-liquid phase change region is a condensation heat exchanger where the gas encounters a low-temperature fluid flowing in a pipeline. The solid-liquid phase change region is located at the lower end of the device and is composed of a phase change material and a heat-conducting liquid. The gas-liquid phase change region is located at the upper end of the device, and the gas-liquid phase change region is liquid. The liquid is incompatible with the heat-conducting liquid in the solid phase change region, and there is a density difference.

[0036] Step 1: When the system is in heat storage: The lower phase change zone is solid (solidified after heat release). The device needs to be inverted. At this time, the liquid in the gas-liquid phase change zone immerses the heat exchange tubes and makes contact with them. At the same time, the solid phase change material, due to its stickiness after heat release, will adhere to the wall. Therefore, the fluid in the tube will heat the liquid in the gas-liquid phase change zone to boiling. The boiling gas will impact the surface of the solid phase change material, accelerating its melting.

[0037] S11, the dual-phase change direct contact phase change heat storage device is turned upside down, and the liquid in the gas-liquid phase change zone is immersed in the heat exchange tube with high-temperature fluid flowing, and the liquid is heated to boiling;

[0038] S12, the liquid in the gas-liquid phase change region is heated, boiled, and vaporized, and then impacts the phase change material in the solid-liquid phase change region, accelerating the melting of the solid phase change material, and realizing a large heat flow phase change to store heat;

[0039] Step 2: When the system is in the process of heat release: when the solid-liquid phase change material is liquid (indicating that melting / heat absorption is completed), when heat release is required, since the liquid after heat absorption and melting is a high-temperature liquid, the gas-liquid phase change area will contact the high-temperature area below and there will be a vaporization process. After vaporization, it rises to the low-temperature heat exchange tube. After encountering the low-temperature tube, the high-temperature gas will condense into droplets and fall back into the solid-liquid phase change area, repeating the cycle.

[0040] S21. Place the dual-phase change direct contact phase change heat storage device upright. When the solid-liquid phase change zone is a high-temperature liquid, heat storage is complete. At this time, the liquid in the gas-liquid zone contacts the high-temperature liquid in the underlying phase change zone.

[0041] S22. When the liquid in the gas-liquid zone comes into contact with high temperature, it vaporizes and rises to the heat exchange tube with cold fluid flowing there. When the high-temperature gas comes into contact with the low-temperature heat exchange tube, it condenses and falls back to the high-temperature phase change zone, transferring heat to the cold fluid. This cycle repeats to achieve large heat flow and heat release.

[0042] Example 3:

[0043] like Figure 3 As shown, the present invention provides a technical solution: a gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method, including two phase change regions, namely a solid-liquid phase change region and a gas-liquid phase change region, and including the following structures: a pipe box 1, a pipe box 2, a phase change heat storage material PCM (solid-liquid phase change region), and a serpentine pipe. The solid phase change material in the solid-liquid phase change region absorbs heat and melts through a hot fluid to store phase change latent heat. The gas-liquid phase change region is a condensation heat exchanger where the gas encounters a low-temperature fluid flowing in a pipeline. The solid-liquid phase change region is located at the lower end of the device and is composed of a phase change material and a heat-conducting liquid. The gas-liquid phase change region is located at the upper end of the device, and the gas-liquid phase change region is liquid. The liquid is incompatible with the heat-conducting liquid in the solid phase change region, and there is a density difference.

[0044] Step 1: When the system is in the heat storage phase, the lower phase change zone is solid (solidified after exothermic reaction). The device is inverted. The liquid in the gas-liquid phase change zone now immerses the heat exchange tubes, making contact with them. Simultaneously, the solid phase change material, having solidified after exothermic reaction, becomes sticky and adheres to the wall. Consequently, the fluid in the tubes heats the liquid in the gas-liquid phase change zone, causing it to boil. The boiling gas impacts the surface of the solid phase change material, accelerating its melting.

[0045] S11, the dual-phase change direct contact phase change heat storage device is turned upside down, and the liquid in the gas-liquid phase change zone is immersed in the heat exchange tube with high-temperature fluid flowing, and the liquid is heated to boiling;

[0046] S12, the liquid in the gas-liquid phase change region is heated, boiled, and vaporized, and then impacts the phase change material in the solid-liquid phase change region, accelerating the melting of the solid phase change material, and realizing a large heat flow phase change to store heat;

[0047] Step 2: When the system is in the process of heat release: when the solid-liquid phase change material is liquid (indicating that melting / heat absorption is completed), when heat release is required, since the liquid after heat absorption and melting is a high-temperature liquid, the gas-liquid phase change area will contact the high-temperature area below and there will be a vaporization process. After vaporization, it rises to the low-temperature heat exchange tube. After encountering the low-temperature tube, the high-temperature gas will condense into droplets and fall back into the solid-liquid phase change area, repeating the cycle.

[0048] S21. Place the dual-phase change direct contact phase change heat storage device upright. When the solid-liquid phase change zone is a high-temperature liquid, heat storage is complete. At this time, the liquid in the gas-liquid zone contacts the high-temperature liquid in the underlying phase change zone.

[0049] S22. When the liquid in the gas-liquid zone comes into contact with high temperature, it vaporizes and rises to the heat exchange tube with cold fluid flowing there. When the high-temperature gas comes into contact with the low-temperature heat exchange tube, it condenses and falls back to the high-temperature phase change zone, transferring heat to the cold fluid. This cycle repeats to achieve large heat flow and heat release.

[0050] During use, when the system is in heat storage: the dual-phase change direct contact phase change heat storage device needs to be placed upside down, and the hot fluid flows through the U-shaped tube, spiral tube, and serpentine tube. The hot fluid passes through the inverted phase change heat storage material PCM area, and uses the phase change material to store the potential energy in the liquid and solid phase changes, thereby achieving higher space efficiency than sensible heat storage, and achieving the purpose of large heat flow phase change latent heat storage. When the system is in heat release: the dual-phase change direct contact phase change heat storage device is placed upright. At this time, low-temperature fluid flows in the tube, and high-temperature gas is generated from the phase change heat storage area at the lower end. The high-temperature gas rises to contact with the U-shaped tube, spiral tube, and serpentine tube to condense. After condensation, the liquid falls back into the phase change heat storage area and then undergoes the heat storage process. The condensation heat exchange is to transfer heat to the fluid in the tube, achieving the purpose of large heat flow heat release.

[0051] In summary, the dual-phase change direct contact heat storage is not affected by the wall resistance and the direct contact of solid-liquid and gas-liquid phase changes can achieve large heat flow heat exchange, thus effectively solving the problems of small heat exchange capacity and long heat storage and release time of phase change heat storage.

[0052] The dual-phase-change direct-contact heat storage system consists of two phase-change zones: the first, a solid-liquid phase-change zone located at the bottom of the device, primarily consists of phase-change material and a heat-conducting liquid; the second, located at the top, consists of gas and fluid. By combining two zones for heat exchange and storage, the system's heat transfer capacity is significantly increased, saving both charging and discharging time and improving system efficiency.

[0053] By combining two phase-change zones within a cylindrical structure, the device achieves distinct partitions, a seamless, airtight seal, and prevents leakage of the heat storage material. Furthermore, the three device modes provided by the present invention offer a simple structure and ease of mobility, significantly reducing the structural complexity and mobility challenges of conventional direct-contact phase-change heat storage.

[0054] By comparison with the direct contact type: when storing heat, the comparison with the general direct contact type is as follows. In the invention method we applied for, when the solid phase change material is stored again and turned upside down, the impact of gasification will cause the phase change material to fall and move, increasing the heat exchange area, while the general direct contact solid phase change material is not mobile and only has a strong heat exchange effect near the channel; when releasing heat, due to the joint action of gas-liquid phase change and solid-liquid phase change, the overall phase change releases heat to achieve large heat flow heat exchange; compared with the indirect type: when storing heat, the outside of the indirect tube is solid phase change material, with a large thermal resistance, and the outside of the heat transfer tube is liquid, with a small thermal resistance and a large boiling heat exchange; when releasing heat, the vaporized gas in the gas-liquid zone will condense and exchange heat when it encounters the cold tube. The condensation heat exchange is phase change heat, which achieves a large heat release.

[0055] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0056] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and 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. A gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method, characterized in that: The method uses a dual-phase-change direct-contact phase-change heat storage device; The dual-phase change direct contact phase change heat storage device is divided into a solid-liquid phase change region and a gas-liquid phase change region. The solid-liquid phase change region is located at the lower end of the device and contains a phase change material and a heat-conducting liquid; the gas-liquid phase change region is located at the upper end of the device and contains a liquid that has a density difference and is incompatible with the heat-conducting liquid in the solid-liquid phase change region. The solid-liquid phase change region occupies the majority of the dual-phase change direct contact phase change heat storage device and is not provided with heat exchange tubes. The gas-liquid phase change region is provided with heat exchange tubes, which are in the form of spiral coils, serpentine tubes or U-shaped tubes. The dual-phase change direct contact phase change heat storage device is also provided with a pipe box. The method comprises the following steps: Step 1: When the system is in heat storage: S11, the dual-phase change direct contact phase change heat storage device is turned upside down, and the liquid in the gas-liquid phase change zone is immersed in the heat exchange tube with high-temperature fluid flowing, and the liquid is heated to boiling; S12, the liquid in the gas-liquid phase change region is heated, boiled, and vaporized, and then impacts the phase change material in the solid-liquid phase change region, accelerating the melting of the solid phase change material, and realizing a large heat flow phase change to store heat; Step 2: When the system is exothermic: S21. Place the dual-phase change direct contact phase change heat storage device upright. When the solid-liquid phase change zone is a high-temperature liquid, heat storage is complete. At this time, the liquid in the gas-liquid phase change zone contacts the high-temperature liquid in the underlying solid-liquid phase change zone. S22. When the liquid in the gas-liquid phase change area contacts the high-temperature liquid, it vaporizes and rises to the heat exchange tube where the cold fluid flows. When the high-temperature gas contacts the low-temperature heat exchange tube, it condenses and falls, transferring heat to the cold fluid. This cycle repeats to achieve a large heat flow and heat release.

2. The gas-liquid-solid-liquid dual phase change direct contact phase change heat storage method according to claim 1, characterized in that: The solid phase change material in the solid-liquid phase change area is accelerated to melt by the combined action of the boiling gas and the high-temperature liquid, thereby achieving the phase change latent heat to store heat.

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