A hierarchical thermal management cooling vest and a multi-stage synergistic heat dissipation system thereof

Abstract

This invention discloses a cooling vest with graded thermal management and its multi-level synergistic heat dissipation system. The vest includes an inner layer, a hydrogel layer, and a phase change material (PCM) layer arranged sequentially from the inside out. The inner layer is a one-way moisture-wicking layer used to unidirectionally guide sweat from the skin side and keep the skin dry. The hydrogel layer is used to store liquid water and provides the main cooling capacity through ice melting and water evaporation. The PCM layer is used to maintain the low temperature of the hydrogel layer and assists in its efficient capture of water vapor. By precisely controlling the melting point of the PCM at 27-28°C, the surface temperature of the hydrogel layer is stabilized at 29-30°C when worn, forming a vapor pressure difference with the skin temperature. This preferentially drives the sweat evaporation path, achieving multi-level synergistic heat dissipation with "evaporation priority, hydrogel layer as the main force, PCM as an auxiliary, and condensate water as a supplement": firstly, sweat evaporation is used as the main cooling path; secondly, the PCM absorbs the remaining heat; and finally, condensate water is stored and replenished by evaporation after the PCM becomes ineffective, further extending the cooling time.

Description

Technical Field

[0001] This invention relates to the field of cooling vest technology, specifically to a cooling vest with graded thermal management and its multi-level synergistic heat dissipation system. Background Technology

[0002] Cooling vests are wearable personal thermal protection equipment, mainly used in high-temperature work scenarios such as construction, fire fighting, and metallurgy. They help the human body dissipate metabolic heat and block environmental heat load, thereby delaying heat stress and ensuring work safety. However, traditional cooling vests mostly use a single phase change material for cold storage or water-absorbing material for evaporation, which has inherent defects such as limited cold storage, short duration of action, and single heat dissipation path. More importantly, these technologies often treat sweat evaporation and phase change cold storage as two independent heat dissipation paths, failing to coordinate and schedule them according to the dynamics of human body heat production, resulting in wasted cooling resources and poor wearing comfort.

[0003] The prior art patent document with authorization announcement number CN115606884A discloses "a cooling vest", which includes a vest body, the vest body including a front piece and a back piece; the front piece includes a front left piece and a front right piece, the front left piece and the front right piece are respectively connected to the back piece, and the opposite sides of the front left piece and the front right piece are connected to each other by a zipper; the front piece and the back piece are provided with mutually cooperating Velcro at the corresponding shoulder and waist positions, and the front piece and the back piece are connected to each other by Velcro; the inside of the front piece and the back piece are provided with several pockets, and the pockets are filled with a cooling agent; the front piece and the back piece are both three-layer structures, from the inside to the outside being a moisture-wicking layer, a heat-insulating layer and a surface layer.

[0004] Patent document CN110393327A discloses "A High-Temperature Work Cooling and Dehumidifying Vest Using Phase Change Material and Radiation Reflective Film," comprising a reflective insulation film, a phase change module, an air layer, a moisture-absorbing layer, a zipper, a front zipper, and the vest body. This invention utilizes the cold-storing properties of phase change materials, combined with a reflective insulation film and a moisture-absorbing layer. During operation, the reflective insulation film reflects heat radiation from the surrounding environment while simultaneously isolating the vest from partial convective heat exchange with the environment. The phase change material melts upon heating, undergoing a phase change to absorb a large amount of latent heat, thus lowering the temperature inside the vest. The moisture-absorbing layer absorbs sweat from the body, ensuring dryness.

[0005] While existing technologies can achieve basic cooling effects through phase change materials and cold storage agents, and improve the dryness of the wearer by incorporating moisture-wicking and moisture-absorbing structures, and allow for adjustable vest structures via Velcro to accommodate different body types, the design without powered components gives cooling vests advantages such as low failure rate, long-term reusability, and low manufacturing and maintenance costs. Furthermore, they can mitigate heat stress to some extent by using reflective insulation films to reflect ambient heat radiation and block some convective heat transfer. However, existing technologies have the following shortcomings: First, at the thermal management architecture level, existing technologies fail to construct a hierarchical thermal management architecture. They cannot achieve coordinated scheduling of sweat evaporation and phase change cooling based on the dynamics of human body heat production. The heat dissipation path remains a single mode, and the melting point of the phase change material (PCM) does not precisely match the human body's evaporative cooling threshold. The technology fails to disclose the crucial matching range achieved by precisely controlling the PCM melting point to 2728℃, stabilizing the surface temperature of the hydrogel layer at 2930℃ during wear, and establishing a vapor pressure difference with skin temperature. Experiments have verified that when the PCM melting point is below 27℃, the surface temperature of the hydrogel layer is too low, inhibiting sweat evaporation; above 28℃, the surface temperature of the hydrogel layer is too high, resulting in insufficient evaporation driving force and reduced skin cooling sensation. Therefore, 2728℃ is the optimal technical solution for achieving multi-level coordinated heat dissipation with "evaporation priority, PCM assistance, and condensate replenishment." Existing technologies cannot prioritize the sweat evaporation path, easily leading to problems such as low cooling efficiency and localized hot spot effects. Furthermore, the lack of resource-based capture and secondary utilization design for condensate results in a waste of cooling resources.

[0006] Secondly, at the functional structure level, some moisture-wicking and moisture-absorbing structures lack backflow prevention design, which can easily lead to liquid water flowing back to the skin side, seriously affecting wearing comfort and evaporative heat dissipation efficiency; the selection of materials and parameter design of the heat insulation structure are not deeply coordinated with the heat dissipation system, which cannot effectively block the environmental heat load and can easily lead to rapid consumption of cooling capacity.

[0007] In summary, existing technologies are insufficient to meet the long-term thermal protection requirements for high-temperature, heavy-duty work. Summary of the Invention

[0008] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a cooling vest with graded thermal management and its multi-level collaborative heat dissipation system, solving the problems mentioned in the background section.

[0009] (II) Technical Solution A cooling vest with graded thermal management includes a three-layer structure arranged sequentially from the inside out: Vest body, The inner layer, which comes into contact with the skin, is used to absorb sweat and conduct it unidirectionally from the skin side to the side away from the skin, while keeping the skin side dry. A hydrophobic layer, disposed on the outer side of the inner layer, is used to store liquid water and provide cooling through ice melting and water evaporation; A PCM layer is disposed on the outside of the condensation layer to absorb heat from the condensation layer in order to maintain the low temperature of the condensation layer. The melting point of PCM is set so that the surface temperature of the hydrogel layer is stabilized at 29-30°C when worn, forming a vapor pressure difference with the skin temperature, which drives the sweat evaporation path to be activated preferentially, realizing multi-level coordinated heat dissipation with evaporation priority, hydrogel layer as the main force, PCM as the auxiliary force, and condensation water as the supplement; and the cold energy stored in the hydrogel layer in the frozen state is greater than the cold energy stored in the PCM layer. The hydrogel layer can be pre-wetted and frozen, and the cooling performance of the cooling vest can be adjusted by adjusting the degree of wetting.

[0010] Furthermore, the melting point of PCM is 27-28℃, and the inner layer is a double-layer unidirectional moisture-wicking structure. The side that contacts the skin is composed of the hydrophobic surface of the inner layer, and the other side is composed of the hydrophilic surface of the inner layer. The hydrophilic fiber side of the inner layer is provided with a positioning strip, which is made of soft elastic material and is used to forcibly maintain the air layer between the inner layer and the adjacent layer.

[0011] Furthermore, the hydrogel layer is composed of hydrophilic fiber fabric and is composed of one, two, or three composite layers.

[0012] Furthermore, it also includes a hydrophobic porous and breathable intermediate layer disposed between the inner layer and the hydrogel layer, for providing a water vapor channel and blocking the backflow of liquid water, wherein the intermediate layer is a hydrophobic porous and breathable layer.

[0013] Furthermore, the PCM layer comprises a phase change material and a polymer network for supporting the phase change material. The phase change material has a melting point of 27-28°C and is preferably n-octadecane. The PCM layer is wrapped with a TPU film to prevent the phase change material from leaching out.

[0014] Furthermore, the back of the vest body is also provided with an aerogel insulation layer.

[0015] Furthermore, the inner layer, middle layer, and hydrogel layer are fixed at the hem with stitching and are stitched to the vest shell at the neckline, armholes, and shoulders to form an overall hanging structure; the PCM layer is an independent module that can be detachably housed in a pocket inside the vest shell; the PCM layer may include an aerogel insulation layer; the PCM layer, TPU film, and aerogel insulation layer are composited to form a detachable PCM module; this PCM module is housed in a pocket inside the vest body and is secured by a combination of Velcro hook and loop fastener closure and a pocket flap design; the positioning strip is located on the hydrophilic side of the inner layer.

[0016] The present invention also provides a pre-cooling method for the cooling vest as described above, comprising: a) Wet the vest body to a preset moisture content, wherein the vest body comprises at least an inner layer, a hydrogel layer and a vest outer shell permanently bonded together; b) Freeze the soaked vest in an environment below 0°C; c) Before wearing, insert the PCM layer into the pocket of the vest body; wherein the preset moisture content is adjusted by controlling the dehydration time.

[0017] The present invention also provides a cleaning method for the cooling vest as described above, wherein the main body of the vest can be machine washed or hand washed, with a water temperature ≤30℃; the PCM layer cannot be washed with water, and the outer surface can only be wiped with a damp cloth.

[0018] Furthermore, cooling vests can be applied to individual thermal protection in high-temperature environments.

[0019] (III) Beneficial Effects Compared with the prior art, the present invention has the following beneficial effects: Precise temperature control and evaporation priority mechanism: By precisely controlling the melting point of PCM at 2728℃, the surface temperature of the hydrogel layer is stabilized at 2930℃ during wear, creating a stable vapor pressure difference with the skin temperature (approximately 34℃). This prioritizes the evaporation of sweat, achieving multi-level synergistic heat dissipation through "evaporation priority, PCM assistance, and condensation replenishment." This mechanism fully utilizes the evaporation of natural human sweat as the primary cooling method, avoiding the problems of traditional PCM vests where the melting point is too low, inhibiting evaporation, or too high, resulting in insufficient cooling.

[0020] Highly efficient resource utilization and long-lasting operation: By setting up a condensate layer to capture water vapor generated by evaporation and store it as condensate, the stored condensate can continue to provide cooling through secondary evaporation after the PCM's cooling capacity is exhausted, effectively extending the cooling time. At the same time, the condensate layer can be pre-wetted and frozen, using the latent heat of ice melting to further supplement the cooling capacity, realizing multi-stage utilization of cooling capacity and significantly improving system energy efficiency.

[0021] A dry and comfortable wearing experience: A one-way moisture-wicking layer conducts sweat from the skin side to the outer layer, keeping the skin side continuously dry. An optional hydrophobic, porous, breathable middle layer effectively blocks liquid water backflow, preventing sweat seepage and further enhancing comfort. Meanwhile, positioning strips on the inner polyester side maintain an air gap between the inner and adjacent layers, ensuring a stable vapor pressure difference and evaporation efficiency.

[0022] Long-lasting energy saving and adaptability to multiple scenarios: The optional aerogel insulation layer can effectively block ambient heat input, reduce cooling consumption, and extend the effective working time, especially suitable for extreme high temperature or direct sunlight environments; in normal environments, the aerogel layer can be omitted, and the system can still achieve excellent cooling effect, flexibly adapting to different application scenarios and cost requirements. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the vest of the present invention; Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the middle AA section; Figure 3 This is a flowchart illustrating the working principle of hierarchical and coordinated heat dissipation.

[0024] In the picture: 1: Vest body 2: Inner layer 3: Intermediate layer 4: Hydrogel layer 5: PCM layer 6: Aerogel insulation layer 7: Inner hydrophobic surface 8: Inner hydrophilic surface 9: Positioning strip 10: Velcro hook side 11: Velcro textured surface 12: TPU film Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1 (Permanent composite structure with intermediate layer 3) 1. Material Preparation Note: The adhesive material is a polyurethane hot melt adhesive film with a thickness of 0.05 mm; polypropylene is the inner hydrophobic surface 7, and polyester is the inner hydrophilic surface 8.

[0027] 2. Preparation steps (1) Inner layer 2 pretreatment: washing, drying, and cutting to the required size.

[0028] (2) Pretreatment of intermediate layer 3: rinse with clean water and dry at 60°C.

[0029] (3) Installation of positioning strip 9: The foamed silicone strips are heat-pressed or sewn onto the polyester side of the inner layer 2 (i.e. the side away from the skin) in a longitudinal layout (2-3 strips on the front chest and 3-4 strips on the back).

[0030] (4) Pretreatment of hydrogel layer 4: Stack the three layers of waffles neatly and composite them by dot hot pressing (adhesive dots diameter 3mm, spacing 5mm), temperature 120-130℃, pressure 0.5MPa, time 15 seconds.

[0031] (5) Interlayer Assembly: The inner layer 2 (polypropylene side up, in contact with the skin), the middle layer 3, and the hydrogel layer 4 are stacked in sequence. The hydrogel layer 4 itself has been bonded together with the three waffle layers by point-like hot pressing. The positioning strip 9 has been pre-installed between the polyester side of the inner layer 2 and the adjacent layer (the middle layer 3 when there is one; the hydrogel layer 4 when there is no middle layer 3). The stacked inner layer 2, middle layer 3, and hydrogel layer 4 are combined as a whole and fixed together at the hem by stitching. They are then sewn to the vest shell at the neckline, armholes, and shoulders, so that the three layers hang as a whole inside the vest shell. The hem is not sewn to the vest shell, leaving an opening for inserting the PCM layer 5 module. This structure allows the positioning strip 9 to freely open the air layer between the inner layer 2 and the middle layer 3 or between the inner layer 2 and the hydrogel layer 4, forming a stable vapor channel to drive sweat evaporation.

[0032] (6) PCM module preparation: Styrene-ethylene-butene-styrene block copolymer (SEBS) / n-octadecane composite sheet was prepared according to the method of Example 2, and TPU film 12 was integrally composited, and aerogel insulation layer 6 was composited with TPU film 12 to form an independent PCM module.

[0033] (7) Install side elastic mesh fabric: Sew an 8cm wide polyester-spandex elastic mesh fabric along the side of the vest (from the armpit to the hem) and connect the front and back pieces.

[0034] (8) Install zipper: Install No. 5 resin zipper in the front and middle, and fix it by hot pressing with TPU hot melt adhesive film at a temperature of 140-160℃, pressure of 0.3-0.5MPa, and time of 10-15 seconds, or sew it securely with a sewing machine.

[0035] (9) Pocket setting: A pocket is set on the inside of the vest shell. The PCM module is placed in the pocket and double-fixed by Velcro (10, 11) closure and pocket flap design.

[0036] 3. Structural characteristics The middle layer 3 has good hydrophobicity, with a water contact angle >120° and excellent breathability. It can effectively prevent liquid water from flowing back to the inner layer 2, while providing a dedicated transmission channel for water vapor, which greatly improves the steam condensation efficiency and condensate capture rate. The positioning strip 9 forcibly maintains the air layer between the inner layer 2 and the adjacent layers. The cooperation of each layer enables the vest to effectively cool down for 5-7 hours in high-temperature environments, while keeping the skin dry and improving wearing comfort.

[0037] Example 2 (Preparation of a bilayer structure without intermediate layer 3) Based on Example 1, the intermediate layer 3 is omitted, while the other structures remain the same.

[0038] 1. Material Preparation Similar to Example 1, only the pure polypropylene woven fabric corresponding to the middle layer 3 is removed.

[0039] 2. Preparation steps (1) Inner layer 2 pretreatment: Same as in Example 1.

[0040] (2) Installation of positioning strip 9: The foamed silicone strips are heat-pressed or sewn onto the polyester side of the inner layer 2 (i.e. the side away from the skin) in a longitudinal layout (2-3 strips on the front chest and 3-4 strips on the back).

[0041] (3) Pretreatment of hydrogel layer 4: Stack the three layers of waffles neatly and composite them by point hot pressing (glue dots diameter 3mm, spacing 5mm), temperature 120-130℃, pressure 0.5MPa, time 15 seconds.

[0042] (4) Interlayer Assembly: The inner layer 2 (polypropylene side up, in contact with the skin) and the hydrogel layer 4 are stacked sequentially without heat-pressing. The positioning strip 9 is located between the polyester side of the inner layer 2 and the hydrogel layer 4. The stacked inner layer 2 and hydrogel layer 4 are combined as a whole and fixed together at the hem with stitching. They are then sewn to the vest shell at the neckline, armholes, and shoulders, allowing the two layers to hang inside the vest shell as a whole. The hem is left unsewn, leaving an opening for inserting the PCM layer 5 module. This structure allows the positioning strip 9 to freely expand the air layer between the inner layer 2 and the hydrogel layer 4, forming a stable vapor channel.

[0043] (5) PCM module preparation: Same as in Example 1, the module includes PCM layer 5, TPU film 12 and an aerogel insulation layer 6 (thickness 3mm or 6mm) optionally laminated on the back side.

[0044] (6) Pocket setting: A pocket is set on the inside of the vest shell. The PCM module is put into the pocket and sealed and fixed by Velcro (10, 11) and flap design to prevent the PCM board from falling off.

[0045] 3. Structural characteristics Without the intermediate layer 3, the inner layer 2 and the condensate layer 4 are directly adjacent, resulting in a shorter steam transmission path. The condensate layer 4 may directly contact liquid water, leading to a slightly lower condensate capture rate. However, the inner layer 2 and the condensate layer 4 can still achieve the core logic of multi-level coordinated heat dissipation. In a high-temperature environment of 35℃ / 60%RH, this double-layer vest can still achieve effective cooling for 4-6 hours, meeting the thermal protection requirements of basic high-temperature operations.

[0046] Example 3: Pre-humidification freezing method (whole garment freezing solution) Based on the cooling vest of Example 1, a whole-garment pre-wetting and freezing method was used for pre-cooling treatment, as follows: Freezeable module: Vest body 1, including an inner layer 2, a middle layer 3, a hydrogel layer 4 permanently bonded together, and a vest shell (excluding PCM module).

[0047] Pre-wetting process: Immerse the vest body 1 in room temperature water (20-25℃) for 3-5 minutes to allow it to fully absorb water. After removing it, place it in a washing machine and select the "spin" program, spinning for 60 seconds (or manually wring it until it no longer drips), so that the vest body 1 reaches a state of "wet but not dripping" (moisture content of approximately 50-80%). At this point, the water absorption of the hydrogel layer 4 is approximately 140-210g (depending on the number of waffle layers), and the water absorption of the inner layer 2 is approximately 40g.

[0048] Freezing procedure: Place the spun-dry vest body 1 into a sealed bag and put it in the freezer. Set the freezing temperature to -18℃ and freeze for at least 12 hours. Before use, remove it from the freezer and let it sit at room temperature for 1-2 minutes to soften slightly and avoid the vest becoming hard and brittle at low temperatures, which would affect the wearing experience.

[0049] Preparation for wearing: Take the PCM module (including PCM layer 5, TPU film 12 and optional aerogel insulation layer 6) out of the freezer and put it into the pocket on the inside of the vest body 1. Secure it with Velcro (10, 11) and the flap design to complete the vest assembly.

[0050] Workflow: Initially, the ice stored in the hydrogel layer 4 melts and absorbs heat, providing approximately 70-140 kJ of additional cooling capacity (calculated based on the water content of the hydrogel layer 4). This cooling release process does not consume the cooling capacity of the PCM layer 5. After the ice has completely melted, the vest enters a normal multi-stage coordinated heat dissipation cycle of evaporation-condensation-phase change cooling storage. Example 4: Performance Testing

[0051] To compare the heat dissipation performance of Example 1 and Example 2, and to verify the rationality of the melting point parameters of the phase change material, standardized performance tests were conducted on the two cooling vests, as detailed below: Test conditions: To simulate the actual environment of high-temperature operations, the ambient temperature was set at 35℃ and the relative humidity at 60%RH; a simulated human body heat source was used, with the power set at 350W / m². 2 Both vests use 1.5kg of n-octadecane + SEBS composite for the PCM layer 5, and the aerogel insulation layer 6 is 3mm thick with a thermal conductivity of 0.02W / mK.

[0052] Test method: The warm body dummy test method was adopted. Two cooling vests were worn on warm body dummy bodies. During the test, the changes in the dummy's skin temperature were continuously recorded, and the mass change of the hydrocondensation layer 4 was monitored in real time to calculate the amount of condensate stored.

[0053] Performance comparison of different solutions: Example 1: With an intermediate layer 3, the duration of the dummy's skin temperature below 30°C is about 4 hours, the total effective cooling time of the vest can reach 5-7 hours, and the condensation storage capacity of the hydrogel layer 4 is about 50g. Example 2: Without the intermediate layer 3, the duration of the dummy's skin temperature below 30°C is about 3 hours, the total effective cooling time of the vest is 4-6 hours, and the condensate storage capacity of the hydrogel layer 4 is about 30g.

[0054] Performance under different sweating conditions (with intermediate layer option 3): Under conditions of no sweating but only pre-wetting, the vest provides a total effective cooling time of about 4 hours, and the dummy's skin temperature is maintained at 29-32℃. Under moderate sweating conditions (1L / h), the vest provides effective cooling for approximately 6 hours, and the dummy's skin temperature is maintained at 28-30℃. Under conditions of heavy sweating (1.5L / h), the vest provides effective cooling for approximately 7 hours, and up to 8 hours in extreme cases, while maintaining the dummy's skin temperature at 27-29℃.

[0055] Melting point comparison test: To verify the necessity of a 27-28℃ melting point for phase change materials, a control group was set up. Except for the melting point of the phase change material being 24℃, the structure, materials, and parameters of the control group vest were identical to those of the scheme with intermediate layer 3 in Example 1. After testing, the average sweat evaporation rate of the control group was reduced by 20% compared to Example 1, and the total effective cooling time was shortened by 25% compared to Example 1, confirming that the 27-28℃ melting point setting is a key parameter for achieving "evaporation priority, PCM assistance" synergistic heat dissipation. Example 5: Cleaning Method

[0056] The cleaning method for the cooling vest based on Example 1 is as follows: (1) Disassembly: Remove the PCM module (including PCM layer 5, TPU film 12 and optional aerogel insulation layer 6) from the pocket inside the vest body 1.

[0057] (2) Cleaning the vest body 1: Clean the vest body 1 (including the inner layer 2, middle layer 3, hydrogel layer 4 and vest shell that are permanently composited into one piece) by machine washing or hand washing. The water temperature for washing should be controlled at ≤30℃. Use neutral detergent and avoid using fabric softener. Avoid vigorous rubbing during the washing process.

[0058] (3) Spin-drying the vest body 1: Put the washed vest body 1 into the washing machine and select the "spin-drying" program to spin-dry until it is "wet but not dripping" (moisture content of about 50-80%), or wring it out manually until it stops dripping.

[0059] (4) Freezing the main body of the vest 1: Put the dehydrated main body of the vest 1 into a sealed bag and freeze it in the freezer (-18℃) for later use.

[0060] (5) Cleaning the PCM module: Wipe the outer surface of the PCM module with a clean, damp cloth. Do not immerse the PCM module in water. After wiping, store the PCM module separately in the freezer compartment of the refrigerator.

[0061] (6) Assembly before use: Before wearing, take the frozen vest body 1 out of the freezer and let it soften slightly; put the PCM module into the pocket of the vest body 1 and secure it with Velcro (10, 11) and the flap design, and it is ready to use. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A cooling vest with graded thermal management, characterized in that, include: Vest body (1) The inner layer (2) is in contact with the skin and is used to absorb sweat and conduct sweat unidirectionally from the skin side to the side away from the skin, while keeping the skin side dry. A condensation layer (4) is disposed on the outside of the inner layer (2) for storing liquid water and providing cooling through ice melting and water evaporation; PCM layer (5) is disposed on the outside of the condensation layer (4) to absorb heat from the condensation layer (4) in order to maintain the low temperature of the condensation layer (4); The melting point of PCM is set so that the surface temperature of the hydrogel layer (4) is stable at 29-30°C when worn, forming a vapor pressure difference with the skin temperature, driving the sweat evaporation path to be activated preferentially, realizing multi-level coordinated heat dissipation with evaporation priority, hydrogel layer (4) as the main force, PCM as the auxiliary force, and condensation water as the supplement; and the cold energy stored in the hydrogel layer (4) in the frozen state is greater than the cold energy stored in the PCM layer (5). The hydrogel layer (4) can be pre-wetted and frozen, and the cooling performance of the cooling vest can be adjusted by adjusting the degree of wetting.

2. The cooling vest according to claim 1, characterized in that, The melting point of PCM is 27-28℃. The inner layer (2) is a double-layer unidirectional moisture-wicking structure. The side that contacts the skin is composed of the hydrophobic surface (7) of the inner layer, and the other side is composed of the hydrophilic surface (8) of the inner layer. The hydrophilic fiber side of the inner layer (2) is provided with a positioning strip (9). The positioning strip (9) is a soft elastic material used to forcibly maintain the air layer between the inner layer (2) and the adjacent layer.

3. The cooling vest according to claim 1, characterized in that, The hydrogel layer (4) is made of hydrophilic fiber fabric and is composed of one, two or three layers.

4. The cooling vest according to claim 1, characterized in that, It also includes a hydrophobic porous and breathable intermediate layer (3) disposed between the inner layer (2) and the hydrogel layer (4) to provide a water vapor channel and block the backflow of liquid water. The intermediate layer (3) is a hydrophobic porous and breathable layer.

5. The cooling vest according to claim 1, characterized in that, The PCM layer (5) contains a phase change material and a polymer network for supporting the phase change material. The phase change material has a melting point of 27-28°C and is preferably n-octadecane. The PCM layer (5) is wrapped with a TPU film (12) to prevent the phase change material from seeping out.

6. The cooling vest according to claim 1, characterized in that, The back of the vest body (1) is also provided with an aerogel insulation layer (6).

7. The cooling vest according to claim 1, characterized in that, The inner layer (2), the middle layer (3), and the hydrogel layer (4) are fixed at the hem by stitching and are stitched to the vest shell at the neckline, armholes, and shoulders to form an overall hanging structure; the PCM layer (5) is an independent module that can be detachably housed in the pocket inside the vest shell; the PCM layer (5) may include an aerogel insulation layer (6); the PCM layer (5), the TPU film (12), and the aerogel insulation layer (6) are combined into one to form a detachable PCM module; the PCM module is housed in the pocket inside the vest body (1) and is fixed by a double fixation of the hook and loop fastener (10) and the loop fastener (11) and the pocket flap design; the positioning strip (9) is set on the hydrophilic side of the inner layer (2).

8. A pre-cooling method for a cooling vest as described in any one of claims 1-7, characterized in that, Includes the following steps: a) Soak the vest body (1) to a preset moisture content, wherein the vest body (1) includes at least an inner layer (2) permanently composited together, a hydrogel layer (4) and a vest outer shell; b) Freeze the soaked vest body (1) in an environment below 0°C; c) Before wearing, the PCM layer (5) is placed in the pocket of the vest body (1); wherein the preset moisture content is adjusted by controlling the dehydration time.

9. A method for cleaning a cooling vest as described in any one of claims 1-7, characterized in that, The vest body (1) can be machine washed or hand washed at a water temperature of ≤30℃; the PCM layer (5) cannot be washed with water, and the outer surface can only be wiped with a damp cloth.

10. A cooling vest as described in any one of claims 1-7, characterized in that, Cooling vests are used for individual thermal protection in high-temperature environments.

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