A new variable-pitch serpentine plate type phase change cold accumulator structure

Abstract

The utility model belongs to the technical field of heat energy storage and heat supply control, provide a new type of variable interval serpentine plate type phase change cold accumulator structure, including the cold accumulator shell, the serpentine series connection pipe subassembly including the connecting sleeve subassembly between the two opposite side walls of cold accumulator shell and a plurality of setting in the mouth type pipe plate of cold accumulator shell, a plurality of mouth type pipe plates are in parallel, and the connecting sleeve subassembly is used for connecting a plurality of mouth type pipe plates in proper order to make a plurality of mouth type pipe plates form series intercommunication, and the connecting sleeve subassembly is communicated with fluid inlet and fluid outlet, and along the flow direction of fluid, the interval between two adjacent mouth type pipe plates gradually reduces, and the interval between two adjacent mouth type pipe plates is filled with phase change material, and the phase change material is used for carrying out heat exchange with the fluid in the mouth type pipe plate. The utility model discloses variable interval serpentine plate type phase change cold accumulator structure little flow resistance, high heat transfer efficiency, compact structure is applicable to the high power density demand scene.

Description

Technical Field

[0001] This utility model belongs to the field of thermal energy storage and heating control technology, and in particular relates to a novel phase change cold storage structure with variable spacing serpentine plates. Background Technology

[0002] Cooling technology plays a crucial role in peak shaving and load balancing in energy systems. It effectively reduces peak loads on refrigeration systems, improves system energy efficiency, and facilitates the transfer of cold energy in time and space, making it a key supporting technology in cooling and heating energy management. Among various cold storage methods, phase change cold storage has received widespread attention in recent years due to its advantages such as high energy density, good temperature stability, and compact system structure. Phase change materials (PCMs) can absorb or release a large amount of latent heat during phase change, achieving efficient energy storage and release, and are widely used in building energy conservation, cold chain logistics, industrial refrigeration, and heat dissipation of electronic devices.

[0003] Phase change accumulators, as the core component for realizing phase change cold storage, are mainly composed of phase change materials and heat exchanger structures. Their structural design has a decisive impact on system performance. Common structures include shell-and-tube, plate, and packed-bed types. Among these, plate structures, with their compact structure, large heat exchange area per unit volume, and suitability for miniaturized high-density applications, have become a key research direction for improving cold storage efficiency. These accumulators typically guide the heat transfer fluid through serpentine channels to achieve heat exchange with the phase change material in the sandwich layer. However, traditional plate phase change accumulators often use equally spaced serpentine tubes with fixed channel spacing, making it impossible to adjust according to the heat transfer intensity requirements of different areas of the accumulator. This results in insufficient local heat exchange capacity or low material utilization, limiting further improvement in overall cooling efficiency. Especially under conditions requiring high power density and rapid response, traditional structures struggle to simultaneously optimize both cold storage capacity and cooling rate, exhibiting problems such as inflexible structure and unreasonable heat exchange distribution. Therefore, there is an urgent need for a novel variable-pitch serpentine plate phase change accumulator structure that is compact, has low flow resistance, high heat transfer efficiency, and is suitable for high power density demand scenarios. Utility Model Content

[0004] The purpose of this invention is to provide a novel variable-pitch serpentine plate phase change cooler structure to solve the above-mentioned problems.

[0005] To achieve the above objectives, this utility model provides the following solution: a novel variable-spacing serpentine plate phase change coolant structure, comprising: Cold accumulator housing; The serpentine series tube assembly includes a connecting sleeve assembly disposed between two opposite side walls of the cold accumulator housing and a plurality of orifice tube sheets disposed within the cold accumulator housing. The plurality of orifice tube sheets are arranged in parallel. The connecting sleeve assembly is used to connect the plurality of orifice tube sheets end to end in sequence so that the plurality of orifice tube sheets form a series connection. The connecting sleeve assembly is connected to a fluid inlet and a fluid outlet. Along the fluid flow direction, the distance between two adjacent orifice tube sheets gradually decreases. A phase change material is filled between two adjacent orifice tube sheets. The phase change material is used to exchange heat with the fluid inside the orifice tube sheets.

[0006] Preferably, the connecting sleeve assembly includes an upper end cap and a lower end cap that are fixedly connected to the top and bottom of the cold storage housing, respectively. The upper end cap and the lower end cap are respectively provided with a plurality of flow channel cavities. The bottoms of two adjacent orifice tube sheets are sequentially connected through the plurality of flow channel cavities in the lower end cap. The upper end cap also has a connecting cavity on both sides. The tops of the two orifice tube plates on both sides are connected to the two connecting cavities respectively. Among the remaining orifice tube plates, the tops of two adjacent orifice tube plates are smoothly connected through several flow channel cavities inside the upper end cap.

[0007] Preferably, one of the communicating cavities is connected to the fluid inlet, and the other communicating cavity is connected to the fluid outlet. The fluid flows sequentially through the fluid inlet and a plurality of the orifice-shaped tube sheets and flows out from the fluid outlet.

[0008] Preferably, along the fluid flow direction, the spacing between two adjacent orifice plates decreases arithmetically, with the difference being between mm and 5 mm; The maximum interval between two adjacent orifice plates shall not exceed 0.0 mm, and the minimum interval between two orifice plates shall not be less than 0.0 mm.

[0009] Preferably, the material of the orifice tube sheet is selected from, but is not limited to, stainless steel, copper, and aluminum alloy.

[0010] Preferably, the orifice plate is provided with a plurality of flow channels, the number of which is between 0 and 00.

[0011] Preferably, the width of the cross-section of the orifice plate perpendicular to the fluid flow direction is between mm and 0 mm, and the length of the cross-section is between 00 mm and 500 mm.

[0012] Preferably, the phase change material is selected from, but is not limited to, water-expanded graphite composite material, water, and tetradecane-expanded graphite composite material.

[0013] Preferably, the material of the cold storage housing is selected from, but is not limited to, carbon steel, stainless steel, and copper.

[0014] Compared with the prior art, the present invention has the following advantages and technical effects: 1. The variable-pitch tube sheet distribution structure of this utility model changes the thickness of the phase change material sequentially, thereby increasing the heat transfer area of ​​the heat transfer fluid and balancing the consumption rate of the phase change material. This achieves the functions of increasing the cooling power of the accumulator, significantly extending the duration of the low-temperature stage at the outlet, and increasing the cooling capacity. It also optimizes the volumetric power density and cooling density of the accumulator, overcoming the shortcomings of traditional phase change accumulators, such as limited cooling power and low quality of cold energy release.

[0015] 2. This utility model features a variable spacing size optimization design to adapt to different working conditions and phase change materials. By rationally arranging the thickness distribution of the phase change material, it can effectively solve the problem of inconsistent complete phase change time of the phase change material under different conditions, and realize the high efficiency and synchronization of cold energy release of the cold accumulator in various application scenarios, overcoming the limitations of the cold accumulator in the prior art that is difficult to adapt to various working conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the phase change cold storage structure of this utility model; Figure 2 This is a cross-sectional schematic diagram of the phase change cold storage structure of this utility model; Figure 3 This refers to the cooling outlet temperature of the phase change accumulator under different decreasing spacing dimensions in Embodiment 2 of this utility model. Figure 4 This is the cooling liquefaction fraction of the phase change accumulator under different variable spacing sizes in Embodiment 2 of this utility model. Figure 5 This is a cloud map of the liquefaction fraction of the phase change accumulator at different times under different spacing sizes of the phase change accumulator structure in Embodiment 2 of this utility model. Figure 6 This is the cooling capacity of the phase change accumulator under different outlet temperature standards with different variable spacing sizes in Embodiment 2 of this utility model. Figure 7 This is the average power of the phase change accumulator under different outlet temperature standards with different variable spacing sizes in Embodiment 2 of this utility model. Figure 8The cooling outlet temperature of the phase change accumulator under different decreasing spacing dimensions in Embodiment 3 of this utility model; Figure 9 This is the cooling liquefaction fraction of the phase change accumulator under different variable spacing sizes in Embodiment 3 of this utility model. Figure 10 This is a cloud map of the liquefaction fraction of the phase change accumulator at different times under different spacing sizes for the phase change accumulator structure of Embodiment 3 of this utility model; Figure 11 This describes the cooling capacity of the phase change accumulator under different outlet temperature standards with different variable spacing sizes in Embodiment 3 of this utility model. Figure 12 This is the average power of the phase change accumulator under different outlet temperature standards with different variable spacing sizes in Embodiment 3 of this utility model. Figure 13 The cooling outlet temperature of the phase change accumulator under different decreasing spacing dimensions in Embodiment 4 of this utility model; Figure 14 This is the cooling liquefaction fraction of the phase change accumulator under different variable spacing sizes in Embodiment 4 of this utility model. Figure 15 This is a cloud map of the liquefaction fraction of the phase change accumulator at different times under different spacing sizes for the phase change accumulator structure of Embodiment 4 of this utility model. Figure 16 This describes the cooling capacity of the phase change accumulator under different outlet temperature standards with different variable spacing sizes in Embodiment 4 of this utility model. Figure 17 This is the average power of the phase change accumulator under different outlet temperature standards with different variable spacing sizes in Embodiment 4 of this utility model. Among them, 1. Regenerator shell; 2. Tube sheet; 3. Phase change material; 4. Upper head; 5. Fluid inlet; 6. Fluid outlet; 7. Lower head; 8. Flow channel cavity; 9. Connecting cavity. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1: Reference Figures 1-2 As shown, this utility model provides a novel variable-pitch serpentine plate phase change cooler structure, comprising: Cold accumulator housing 1; The serpentine series tube assembly includes a connecting sleeve assembly disposed between two opposite side walls of the regenerator housing 1 and several orifice tube sheets 2 disposed within the regenerator housing 1. The orifice tube sheets 2 are arranged in parallel. The connecting sleeve assembly is used to connect the orifice tube sheets 2 end to end in sequence so that the orifice tube sheets 2 form a series connection. The connecting sleeve assembly is connected to a fluid inlet 5 and a fluid outlet 6. Along the flow direction of the fluid, the distance between two adjacent orifice tube sheets 2 gradually decreases. A phase change material 3 is filled between two adjacent orifice tube sheets 2. The phase change material 3 is used to exchange heat with the fluid inside the orifice tube sheet 2.

[0021] The connecting sleeve assembly can sequentially connect several tube sheets 2 arranged side by side, so that the tube sheets 2 can be connected in a serpentine series when arranged side by side, so that the fluid can fully exchange heat with the phase change material 3. Along the flow direction of the fluid, the interval between two adjacent tube sheets 2 gradually decreases, which can gradually reduce the thickness of the phase change material 3 between two adjacent tube sheets 2. This can increase the heat exchange area of ​​the heat transfer fluid and balance the consumption rate of the phase change material 3. At the same time, it also solves the problem of inconsistent phase change time of the phase change material 3 under different conditions.

[0022] Further optimization of the scheme: the connecting sleeve assembly includes an upper end cap 4 and a lower end cap 7 that are fixedly connected to the top and bottom of the accumulator housing 1, respectively. The upper end cap 4 and the lower end cap 7 are respectively provided with a number of flow channel cavities 8. The bottoms of two adjacent orifice tube sheets 2 are sequentially connected through the number of flow channel cavities 8 in the lower end cap 7. The upper head 4 is also provided with connecting cavities 9 on both sides. The tops of the two orifice tube sheets 2 on both sides are connected to the two connecting cavities 9 respectively. Among the remaining orifice tube sheets 2, the tops of two adjacent orifice tube sheets 2 are smoothly connected through several flow channel cavities 8 inside the upper head 4.

[0023] like Figure 2 As shown, the top and bottom of several orifice tube sheets 2 extend into the flow channel cavity 8 to ensure effective communication between the orifice tube sheet 2 and the upper end cap 4 and the lower end cap 7.

[0024] like Figure 2 As shown, in this embodiment, from left to right, the bottom of the first set of orifice plates 2 and the bottom of the second set of orifice plates 2 are located in the leftmost flow channel cavity 8, the bottom of the third set of orifice plates 2 and the bottom of the fourth set of orifice plates 2 are located in the second flow channel cavity 8 from the left, and so on, with the bottom of the rightmost orifice plate 2 and the bottom of the second set of orifice plates 2 from the right located in the rightmost flow channel cavity 8; Similarly, the top of the leftmost orifice tube sheet 2 is located in the leftmost connecting cavity 9, and the top of the rightmost orifice tube sheet 2 is located in the rightmost connecting cavity 9. For the remaining orifice tube sheets 2, from left to right, the tops of the second and third groups of orifice tube sheets 2 are located in the leftmost flow channel cavity 8, the tops of the fourth and fifth groups of orifice tube sheets 2 are located in the second flow channel cavity 8 from the left, and so on. This creates a serpentine series connection of several orifice tube sheets 2 between the upper end cap 4 and the lower end cap 7, and the distance between two adjacent orifice tube sheets 2 can be arbitrarily adjusted during the design process without affecting the overall structure of the regenerator.

[0025] In a further optimized design, openings are provided at the top and bottom of the accumulator housing 1, and the upper end cap 4 and the lower end cap 7 are welded together in the openings at the top and bottom of the accumulator housing 1.

[0026] The scheme is further optimized by connecting a fluid inlet 5 to one connecting cavity 9 and a fluid outlet 6 to another connecting cavity 9. The fluid passes through the fluid inlet 5 and several orifice tube sheets 2 in sequence and flows out from the fluid outlet 6.

[0027] like Figure 2 As shown, in this embodiment, since the thickness of the phase change material 3 decreases from left to right, the fluid inlet 5 is located at the left end of the upper head 4, and the fluid outlet 6 is located at the right end of the upper head 4.

[0028] Further optimization of the scheme: along the fluid flow direction, the interval between two adjacent orifice plates 2 is distributed in an arithmetic progression, with the difference between 1mm and 5mm. The maximum interval between two adjacent orifice tube sheets 2 shall not exceed 100 mm, and the minimum interval between two orifice tube sheets 2 shall not be less than 10 mm.

[0029] Further optimization of the scheme, the material selection for the orifice tube sheet 2 is not limited to stainless steel, copper, and aluminum alloy.

[0030] Further optimization of the scheme: the orifice tube sheet 2 is provided with several flow channels (not shown in the figure), and the number of flow channels is between 10 and 100.

[0031] Further optimization of the scheme: the width of the cross-section of the orifice tube sheet 2 perpendicular to the fluid flow direction is between 1mm and 10mm, and the length of the cross-section is between 100mm and 500mm.

[0032] Further optimization of the scheme resulted in the length of the orifice tube sheet 2 being between 100mm and 1000mm.

[0033] To further optimize the scheme, the phase change material 3 may be selected, but is not limited to, water-expanded graphite composite material, water, and tetradecane-expanded graphite composite material.

[0034] To further optimize the design, the material of the cold storage shell 1 may be selected, but is not limited to, carbon steel, stainless steel, and copper.

[0035] Example 2: This example uses a tube sheet 2 with a cross-sectional dimension of 3mm × 360mm and a length of 400mm. The tube sheet 2 consists of 24 flow channels, each with an orifice diameter of 2mm × 14.5mm and a wall thickness of 0.5mm. To reduce the computational load of the numerical simulation, it is assumed that the fluid distribution is uniform throughout the regenerator. Based on the flow channel composition, the regenerator structure is divided into 24 parallel modules. Only a single regenerator module is simulated. Each module has a height of 400mm, a width of 300mm, and a thickness of 15mm. The thickness refers to the dimension of a single parallel module in the width direction of the original tube sheet. Since the 24 flow channels are equivalently connected in parallel, the thickness is 1 / 24th of the inlet cross-sectional length of the tube sheet.

[0036] This example studies the impact of variable spacing design on the cooling performance of a cold storage regenerator. Three variable spacing sizes were selected: spacing decreasing by 1mm, 2mm, and 3mm. Under the same operating conditions, the results were compared with the equal-spacing structure in Comparative Example 1. The corresponding phase change material thicknesses are shown in Table 1. The phase change material used was a water-expanded graphite composite phase change material with a strength of 7.41 W / (m·K); the total inlet flow rate was 2400 L / h, and the inlet temperature was 10℃.

[0037] Table 1. Thickness of phase change material at different locations in the variable-pitch serpentine plate regenerator.

[0038] like Figure 3 and Figure 4 As shown, among the three variable spacing structures, the one-mm decrease in spacing performs best. It has a longer duration of the lower cooling outlet temperature phase, a more rapid temperature rise, and allows for the release of more cooling energy at low temperatures, resulting in the shortest time required for the phase change material to complete its phase change. The two-mm decrease in spacing is the second best, while the three-mm decrease in spacing shows a significant deterioration in the cooling curve, representing a negative optimization.

[0039] Figure 5 The diagram shows the PCM liquefaction fraction contour maps within four different regenerator structures at various time points. In the equidistant structure, due to the temperature difference between the inlet and outlet, the consumption rate of the phase change material varies at different locations, resulting in significant differences in the time to complete phase change. For example, at 720 s, the phase change material at the regenerator inlet has completed phase change, but it is not until 1250 s that all the phase change material in the regenerator completes phase change. As can be seen from the outlet temperature curve, the inflection point of rapid temperature rise also occurs at 720 s, indicating that the difference in the time to complete phase change of the phase change material at different locations is the reason for the rapid temperature rise phase at the outlet.

[0040] The 1mm decreasing spacing effectively reduced the difference in the complete phase change time of the phase change material at various locations, with the phase change material at the inlet completing its phase change at 900s, which also coincides with the inflection point of the accelerated temperature rise at the outlet. The variable spacing structure extended the time of the low-temperature stage at the outlet, and all phase change materials could complete their phase change at 1079s, but there was still some degree of asynchrony in the complete phase change time at different locations, indicating room for further improvement. In contrast, the 2mm and 3mm decreasing spacing designs resulted in the material at the inlet completing its phase change last, indicating that too much phase change material was added at the inlet. Especially in the 3mm decreasing spacing structure, the material thickness at the inlet was too large, significantly increasing the thermal resistance and ultimately resulting in inferior cooling performance compared to the equal spacing structure.

[0041] like Figure 6 The results show the cooling capacity under different outlet temperature standards. The structure with a 1mm decreasing spacing has the largest cooling capacity under all outlet temperature standards. When the outlet temperature is below 6℃, 7℃, and 8℃, the cooling capacity is increased by 7.3%, 5.7%, and 1.9% respectively compared to the equal spacing structure, indicating that the variable spacing structure can effectively enhance the cooling capacity in the low outlet temperature range.

[0042] like Figure 7 As shown, the average cooling power of the 1mm decreasing spacing structure was 3.2% higher than that of the equal spacing structure when the outlet temperature was below 8°C, which is attributed to its shorter total cooling time. However, when the outlet temperature was below 6°C, its average power decreased slightly, because the duration of this stage was longer, and the power decreased to some extent after being averaged over time.

[0043] Example 3: This example uses a tube sheet 2 with a cross-sectional dimension of 3mm × 360mm and a length of 400mm, consisting of 24 flow channels, each with an orifice diameter of 2mm × 14.5mm and a wall thickness of 0.5mm. To reduce the computational load of the numerical simulation, it is assumed that the fluid distribution is uniform throughout the cold accumulator, and the cold accumulator is divided into 24 parallel modules. Only a single cold accumulator module is simulated, with each module having a height of 400mm, a width of 300mm, and a thickness of 20mm.

[0044] This example uses three variable spacing sizes: spacing decreasing by 1mm, 2mm, and 3mm. Under the same operating conditions, it is compared with the equal-spacing structure in Comparative Example 2. The corresponding phase change material thicknesses are shown in Table 1 of Example 1. The phase change material used is a water-expanded graphite composite phase change material with a strength of 14.68 W / (m·K); the total inlet flow rate is 2400 L / h, and the inlet temperature is 10℃.

[0045] like Figure 8 and Figure 9As shown, under this operating condition, the structure with the best cooling performance is the one with a spacing decreasing by 2 mm, and the cooling performance of all three variable spacing structures is better than that of the equal spacing structure. Compared with the equal spacing structure, the variable spacing structure prolongs the duration of the low-temperature stage at the outlet and shortens the complete liquefaction time of the phase change material. Specifically, the 2 mm spacing decreasing structure prolongs the duration of the stage where the outlet temperature is below 5℃ from 592 s to 683 s, an increase of 15.4%; the complete phase change time of the phase change material is shortened from 926 s to 730 s, a decrease of 21.2%.

[0046] Figure 10 These are cross-sectional cloud diagrams of the liquefaction fraction of four structural sizes of cold regenerators at different times. Due to the high thermal conductivity of H₂O-0.20EG, the heat transfer performance is significantly enhanced. In the equidistant structure, the phase change material at the inlet completes its phase change at approximately 450s, but the entire material does not complete its phase change until 926s. This indicates that the heat exchange area of ​​the cold regenerator is not fully utilized for more than half of the cooling process. In contrast, the structure with the best cooling performance (2mm decreasing spacing) has a time difference of less than 100s between the phase change at the inlet and the overall phase change, indicating that this structure significantly reduces the difference in the time of complete phase change at different locations, resulting in more efficient cold release. For the 3mm decreasing spacing structure, due to excessive accumulation of phase change material at the inlet, its phase change time is delayed compared to other areas, but its overall cooling performance is still slightly better than the equidistant structure.

[0047] like Figure 11 As shown, the 2mm decreasing spacing structure exhibits the greatest cooling capacity at outlet temperatures below 5℃, 6℃, and 7℃, while the 1mm decreasing spacing structure exhibits the greatest cooling capacity at outlet temperatures below 8℃. Compared to the equal spacing structure, the 2mm decreasing spacing structure increases cooling capacity by 12.9%, 7.8%, 3.1%, and 0.6% at outlet temperatures below 5℃, 6℃, 7℃, and 8℃, respectively. This further indicates that the variable spacing structure can significantly increase the cooling capacity released at low outlet temperatures, but the increase in cooling capacity is limited when higher outlet temperatures are required.

[0048] like Figure 12 As shown, compared with the equal-spacing structure, the average power of the structure with a 2mm decreasing spacing increased from 14.46kW to 15.66kW when the outlet temperature was below 8℃, an increase of 8.3%. This indicates that increasing the cooling capacity of the accumulator at the lower outlet temperature stage can not only shorten the cooling time, but also improve the overall average cooling power of the accumulator.

[0049] Example 4: This example uses a tube sheet 2 with a cross-sectional dimension of 3mm × 240mm and a length of 600mm, consisting of 16 flow channels, each with an orifice diameter of 2mm × 14.5mm and a wall thickness of 0.5mm. To reduce the computational load of the numerical simulation, it is assumed that the fluid distribution is uniform throughout the cold accumulator, and the cold accumulator is divided into 16 parallel modules. Only a single cold accumulator module is simulated, with each module having a height of 600mm, a width of 300mm, and a thickness of 15mm.

[0050] This embodiment studies the cooling performance of a variable-spacing structure in a long flow channel by increasing the flow path length (i.e., increasing the module height from 400mm to 600mm) while keeping the structural form unchanged. The simulation conditions are the same as those in Embodiment 3 above, using a water-expanded graphite composite phase change material of 14.68 W / (m·K), maintaining a flow rate of 1600 L / h, and an inlet temperature of 10℃. The cooling performance of the isostatic structure and the variable-spacing structure (spacing decreasing by 1mm, 2mm, and 3mm) in Embodiment 3 are compared.

[0051] Figure 13 and Figure 14 The cooling performance of regenerators with different variable spacing structures under this operating condition is shown. The optimal structure for the cooling outlet temperature curve is one with a spacing decreasing by 3 mm. Due to the increased flow length, the outlet temperature decreases significantly under constant flow velocity, with the outlet temperature remaining below 3°C for more than half of the cooling phase. Compared to the equal spacing structure, the duration of the outlet temperature below 3°C increased from 639 s to 791 s (a 23.8% extension) with the 3 mm decreasing spacing structure; the complete phase change time of the phase change material decreased from 1192 s to 911 s (a 23.6% reduction). The significant decrease in fluid outlet temperature reduces the heat transfer rate of the phase change material in the outlet region, resulting in a more balanced overall phase change rate for the regenerator, making the 3 mm decreasing spacing the optimal structural dimension.

[0052] Figure 15 The images show cross-sectional cloud diagrams of the liquefaction fraction of four different structural sizes of cold accumulators at various times. It can be seen that in all structures, the phase change material near the inlet undergoes the first complete phase change. Furthermore, as the spacing increases, the time difference between the complete phase change of the phase change material at different locations gradually decreases. Specifically, in structures with a 3mm decreasing spacing, the time difference between the complete phase change of the phase change material at each location is within 100 seconds, essentially achieving synchronization of phase change in each region and improving the efficiency of cold energy release within the cold accumulator.

[0053] Figure 16The cooling capacity of different structures under various outlet temperature standards is presented. Since the accumulator outlet temperature is below 3°C for nearly half the time under this operating condition, the cooling capacity at outlet temperatures below 3°C and 4°C was also statistically analyzed. The results show that the structure with a 3mm decreasing spacing has the largest cooling capacity at outlet temperatures below 3°C, 4°C, and 5°C, respectively increasing by 21.0%, 16.2%, and 9.6% compared to the equally spaced structure. However, in the statistical range where the outlet temperature is below 8°C, the cooling capacity of the structure with a 3mm decreasing spacing is slightly lower than that of the equally spaced structure.

[0054] like Figure 17 As shown, the average power of the 3mm decreasing spacing structure increased from 11.06kW to 13.38kW, a 21.0% increase, when the outlet temperature was below 8℃, compared to the equal spacing structure. This further illustrates that increasing the cooling capacity of the accumulator at lower outlet temperatures can effectively shorten the cooling time of the accumulator and improve the overall average cooling power of the accumulator.

[0055] Comparative Example 1: This comparative example uses a tube sheet 2 with a cross-sectional dimension of 3mm × 360mm and a length of 400mm, consisting of 24 flow channels, each with an orifice diameter of 2mm × 14.5mm and a wall thickness of 0.5mm. To reduce the computational load of the numerical simulation, it is assumed that the fluid distribution is uniform throughout the cold accumulator, and the cold accumulator is divided into 24 parallel modules. Only a single cold accumulator module is simulated, with each module having a height of 400mm, a width of 300mm, and a thickness of 20mm.

[0056] This comparative example studies the effect of equal spacing design on the cooling performance of the regenerator. The distance between adjacent tube sheets in Table 1 is 30 mm. The phase change material is a water-expanded graphite composite phase change material with a yield of 7.41 W / (m·K); the total inlet flow rate is 2400 L / h, and the inlet temperature is 10℃.

[0057] Comparative Example 2: This comparative example uses a tube with a cross-sectional dimension of 3mm × 360mm and a length of 400mm, consisting of 24 flow channels. Each flow channel has an orifice diameter of 2mm × 14.5mm and a wall thickness of 0.5mm. To reduce the computational load of the numerical simulation, it is assumed that the fluid distribution is uniform throughout the cold accumulator. The cold accumulator is divided into 24 parallel modules, and only a single cold accumulator module is simulated. Each module has a height of 400mm, a width of 300mm, and a thickness of 20mm.

[0058] This comparative example studies the effect of equal spacing design on the cooling performance of the regenerator. The distance between adjacent tube sheets in Table 1 is 30 mm. The phase change material is a water-expanded graphite composite phase change material with a yield of 14.68 W / (m·K); the total inlet flow rate is 2400 L / h, and the inlet temperature is 10℃.

[0059] Comparative Example 3: This comparative example uses a tube with a cross-sectional dimension of 3mm × 240mm and a length of 600mm, consisting of 16 flow channels, each with an orifice diameter of 2mm × 14.5mm and a wall thickness of 0.5mm. To reduce the computational load of the numerical simulation, it is assumed that the fluid distribution is uniform throughout the cold accumulator, and the cold accumulator is divided into 16 parallel modules. Only a single cold accumulator module is simulated, with each module having a height of 600mm, a width of 300mm, and a thickness of 15mm.

[0060] This comparative example studies the effect of equal spacing design on the cooling performance of the regenerator. The distance between adjacent tube sheets in Table 1 is 30 mm. The phase change material is a water-expanded graphite composite phase change material with a yield of 14.68 W / (m·K); the total inlet flow rate is 2400 L / h, and the inlet temperature is 10℃.

[0061] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0062] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A novel variable-pitch serpentine plate phase change coolant structure, characterized in that, include: Cold accumulator housing (1); The serpentine series tube assembly includes a connecting sleeve assembly disposed between two opposite side walls of the cold accumulator housing (1) and a plurality of orifice tube sheets (2) disposed within the cold accumulator housing (1). The plurality of orifice tube sheets (2) are arranged in parallel. The connecting sleeve assembly is used to connect the plurality of orifice tube sheets (2) end to end in sequence so that the plurality of orifice tube sheets (2) form a series connection. The connecting sleeve assembly is connected to a fluid inlet (5) and a fluid outlet (6). Along the flow direction of the fluid, the distance between two adjacent orifice tube sheets (2) gradually decreases. A phase change material (3) is filled between two adjacent orifice tube sheets (2). The phase change material (3) is used to exchange heat with the fluid in the orifice tube sheets (2).

2. The novel variable-spacing serpentine plate phase change regenerator structure according to claim 1, characterized in that: The connecting sleeve assembly includes an upper end cap (4) and a lower end cap (7) that are fixedly connected to the top and bottom of the cold storage housing (1) respectively. The upper end cap (4) and the lower end cap (7) are respectively provided with a plurality of flow channel cavities (8). The bottoms of two adjacent orifice tube sheets (2) are sequentially connected through the plurality of flow channel cavities (8) in the lower end cap (7). The upper end cap (4) is also provided with connecting cavities (9) on both sides. The tops of the two orifice tube plates (2) located on both sides are connected to the two connecting cavities (9) respectively. Among the remaining orifice tube plates (2), the tops of two adjacent orifice tube plates (2) are smoothly connected through a plurality of flow channel cavities (8) in the upper end cap (4).

3. The novel variable-spacing serpentine plate phase change regenerator structure according to claim 2, characterized in that: One of the connecting cavities (9) is connected to the fluid inlet (5), and the other connecting cavity (9) is connected to the fluid outlet (6). The fluid passes through the fluid inlet (5) and a plurality of the orifice tube sheets (2) in sequence and flows out from the fluid outlet (6).

4. The novel variable-pitch serpentine plate phase change regenerator structure according to claim 1, characterized in that: Along the flow direction of the fluid, the interval between two adjacent orifice plates (2) is distributed in an arithmetic progression, with the difference between 1 mm and 5 mm. The maximum interval between two adjacent orifice plates (2) shall not exceed 100 mm, and the minimum interval between two orifice plates (2) shall not be less than 10 mm.

5. The novel variable-pitch serpentine plate phase change regenerator structure according to claim 1, characterized in that: The material of the orifice tube sheet (2) is selected, but is not limited to, stainless steel, copper, and aluminum alloy.

6. The novel variable-pitch serpentine plate phase change regenerator structure according to claim 1, characterized in that: The orifice plate (2) is provided with a plurality of flow channels, the number of which is between 10 and 100.

7. The novel variable-pitch serpentine plate phase change regenerator structure according to claim 1, characterized in that: The width of the cross section of the orifice plate (2) perpendicular to the fluid flow direction is between 1 mm and 10 mm, and the length of the cross section is between 100 mm and 500 mm.

8. The novel variable-spacing serpentine plate phase change regenerator structure according to claim 1, characterized in that: The phase change material (3) mentioned herein may be selected, but is not limited to, water-expanded graphite composite material, water, and tetradecane-expanded graphite composite material.

9. The novel variable-pitch serpentine plate phase change regenerator structure according to claim 1, characterized in that: The material of the cold storage shell (1) is selected, but is not limited to, carbon steel, stainless steel, and copper.

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