Laser heat management system adopting mixed cold storage type evaporator and management method thereof

Abstract

The invention relates to the technical field of laser heat management, in particular to a laser heat management system adopting a mixed cold storage type evaporator and a management method of the laser heat management system, which can realize laser heat management under the conditions of low power consumption and small size. Traditional liquid sensible heat cold storage is replaced by phase change cold storage, the temperature of a cold storage box is increased, the cold storage size is reduced, meanwhile, due to the fact that the cold storage temperature is increased, the refrigerating system can work in a high-efficiency area within the wide temperature range (5-50 DEG C), component model selection is convenient, and energy consumption is saved. Specifically, the variable-frequency pump is adopted in the system to adjust flow so as to control the temperature of the temperature control water tank, compared with a valve adjusting method, one valve is omitted, meanwhile, the variable-frequency pump is adjustable in power, and power consumption is reduced; the mixed cold accumulation type evaporator adopts a phase change cold accumulation and sensible heat cold accumulation mixed form, so that the cold accumulation volume is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of laser thermal management, and in particular to a laser thermal management system adopting a hybrid cold storage evaporator and a management method thereof. Background Art

[0002] Lasers generate a lot of heat during short pulses when they are working, and their peak heat release power is much higher than the low value. For example, the laser system has a heat load of 1MW in 20 seconds and has a low operating temperature. Without a powerful cooling solution, the large amount of waste heat generated by each emission will damage the laser system. In addition, the temperature of the waste heat is relatively low, which makes it more difficult to manage with traditional methods. The use of phase change materials can effectively remove a large amount of low-grade waste heat generated by the inefficiency of equipment (i.e. lasers, microwave transmitters, etc.) while maintaining thermal stability.

[0003] In view of the intermittent working nature of lasers and the low inlet temperature requirements, conventional thermal management systems are equipped with cold storage and refrigeration systems. However, conventional thermal management systems use liquid sensible heat to store cold. The higher the temperature is 7 to 8°C, the larger the cold storage volume is. In addition, due to the low cold storage temperature, the requirements for the refrigeration system are high. When the ambient temperature is high, the efficiency of the refrigeration system decreases, which also makes it difficult to keep warm. Summary of the invention

[0004] In view of this, the present invention provides a laser thermal management system and a management method thereof using a hybrid cold storage evaporator, which can achieve laser thermal management with low power consumption and small volume.

[0005] To achieve the above-mentioned purpose, the present invention provides a laser thermal management system using a hybrid cold storage evaporator, comprising a first water pump, a laser, a temperature-controlled water tank, a heating wire, a second water pump, a hybrid cold storage evaporator, a frequency conversion pump, a radiator and a fan; wherein the temperature-controlled water tank is provided with four openings, namely a hot side inlet, a hot side outlet, a cold side inlet and a cold side outlet; the hot side outlet of the temperature-controlled water tank is connected to the first water pump, the first water pump is connected to the laser through a pipeline, and the first water pump is connected to the hot side inlet of the temperature-controlled water tank through a pipeline after the laser; the cold side outlet of the temperature-controlled water tank is connected to the inlet of the hybrid cold storage evaporator, and the outlet of the hybrid cold storage evaporator is connected to the cold side inlet of the temperature-controlled water tank through the frequency conversion pump; one end of the radiator is connected to the inlet of the hybrid cold storage evaporator through the second water pump, and the outlet of the hybrid cold storage evaporator is connected to the other end of the radiator through a pipeline; the fan is arranged next to the radiator; the heating wire is arranged at the bottom of the temperature-controlled water tank to realize the electric heating function.

[0006] Among them, the hybrid cold storage evaporator integrates liquid sensible heat storage, phase change latent heat storage and refrigeration evaporator, and the evaporator adopts a coil structure.

[0007] Among them, the hybrid cold storage evaporator includes a plate-fin phase change cold storage device and a refrigerant coil; the plate-fin phase change cold storage device is made of aluminum alloy material, including a phase change material side and a water side; the phase change material side adopts serrated or rectangular fins to enhance heat transfer; a phase change material filling port is designed on the upper part of the plate-fin phase change cold storage device, and it is sealed after being filled with about 97% of liquid.

[0008] Among them, phase change cold storage uses solid-liquid phase change materials as cold storage media, and the temperature of the phase change materials is between 15 and 20°C.

[0009] Among them, a condenser is installed in front of the radiator, the condenser output is connected to the expansion valve, the expansion valve is connected to the compressor, and the compressor output is connected to the condenser input; a pressure valve is turned on the upper part of the temperature-controlled water tank, and the pressure valve ensures that the system is not over-pressurized.

[0010] The temperature-controlled water tank includes a water tank shell and an internal heat exchange coil, and the outside of the heat exchange coil is a hot fluid.

[0011] The present invention also provides a management method for a laser thermal management system using a hybrid cold storage evaporator, comprising the following steps:

[0012] Start-up preparation stage: When the ambient temperature is between -40 and 24°C, the laser does not work, the first water pump works, and the system preheats the heat source and the antifreeze in the temperature-controlled water tank to 25±1°C through the electric heating wire; when the ambient temperature is between 26 and 50°C, the first water pump, the variable frequency pump, the second water pump, and the fan work, and the refrigeration cycle works to cool the temperature-controlled water tank to 25±1°C and the outlet temperature of the cold storage evaporator to 16°C;

[0013] Laser working stage: The laser generates heat. When the ambient temperature is between -40 and +5°C, the first water pump works to cool the heat source. The coolant returns to the temperature-controlled water tank. The variable frequency pump changes speed according to the temperature of the temperature-controlled water tank. The coolant absorbs heat from the outlet of the variable frequency pump through the temperature-controlled water tank and then heats up. It then cools down after the cold storage evaporator and then returns to the variable frequency pump to keep the temperature of the temperature-controlled water tank at 25±1°C. At the same time, when the outlet temperature of the hot side of the cold storage evaporator is higher than 16°C, the second water pump starts, and part of the coolant flows through the second water pump, the cold storage evaporator, and the radiator to transfer the heat from the cold storage to the radiator. The fan rotates to take away the heat.

[0014] After the laser is turned on, the laser generates heat. When the ambient temperature is between 5 and +50°C, the first water pump works to cool the heat source, and the coolant returns to the temperature-controlled water tank. The variable frequency pump works at a variable speed according to the temperature of the temperature-controlled water tank. The coolant absorbs heat from the outlet of the variable frequency pump through the temperature-controlled water tank and then heats up. It then cools down after passing through the cold storage evaporator, and then returns to the variable frequency pump to keep the temperature of the temperature-controlled water tank at 25±1°C. At the same time, when the outlet temperature of the hot side of the cold storage evaporator is higher than 16°C, the refrigeration cycle works, and the fan rotates to take away the heat.

[0015] After the laser is turned off, when the ambient temperature is between -40 and 5°C: the first water pump works, and the coolant returns to the temperature-controlled water tank through the laser; the variable frequency pump changes speed according to the temperature of the temperature-controlled water tank to keep the temperature of the temperature-controlled water tank at 25±1°C; the second water pump and fan continue to work, and the coolant flows through the second water pump, the cold storage evaporator, and the radiator, transferring the heat of the cold storage evaporator to the environment until the outlet temperature of the hot side of the cold storage evaporator is less than 16°C;

[0016] After the laser is turned off, when the ambient temperature is between 5 and +50°C: the first water pump, frequency conversion pump, refrigeration cycle and fan work. The refrigeration cycle cools the temperature-controlled water tank to 25±1°C and the outlet temperature of the cold storage evaporator to 16°C.

[0017] Beneficial effects:

[0018] 1. The system of the present invention adopts phase change cold storage to replace the traditional liquid sensible heat cold storage, which increases the temperature of the cold storage box and reduces the cold storage volume. At the same time, due to the increase in the cold storage temperature, the refrigeration system can work in the high-efficiency zone within a wide temperature range (5-50°C), which is not only convenient for component selection, but also saves energy. Specifically, the system uses a variable frequency pump to adjust the flow rate and then control the temperature of the temperature-controlled water tank. Compared with the valve adjustment method, a valve is omitted, and the power of the variable frequency pump is adjustable, saving power consumption; the hybrid cold storage evaporator adopts a mixed form of phase change cold storage and sensible heat cold storage to reduce the cold storage volume.

[0019] 2. The hybrid cold storage evaporator in the system of the present invention integrates the cold storage evaporator and the evaporator into one unit, thereby reducing the volume.

[0020] 3. In the system of the present invention, the temperature-controlled water tank adopts a coil heat exchanger, combining the traditional plate heat exchanger and the water tank into one to reduce the volume.

[0021] 4. In the system of the present invention, the phase change cold storage adopts plate fin type, aluminum alloy material, and the phase change material side adopts serrated or rectangular fins to enhance heat transfer. The upper part is designed with a phase change material filling port, which is sealed after about 97% of the liquid is filled to prevent leakage.

[0022] 5. In the system of the present invention, the phase change cold storage uses solid-liquid phase change materials as the cold storage medium. To ensure the efficiency of the refrigeration cycle, the temperature of the phase change material is 15-20°C, such as pure substances such as n-tetradecane, octanoic acid, polyethylene glycol and their eutectic mixtures. The cold storage material can provide continuous cold in a short time and play a role in stabilizing the cold output.

[0023] 6. The method of the present invention is implemented based on the system of the present invention, and phase change cold storage is used to replace traditional liquid sensible heat cold storage, so as to increase the temperature of the cold storage box and reduce the cold storage volume. At the same time, due to the increase in the cold storage temperature, the refrigeration system can operate in a high-efficiency zone within a wide temperature range (5 to 50°C), which not only facilitates the selection of components but also saves energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The schematic diagram of the system embodiment of the present invention.

[0025] Figure 2 Schematic diagram of a temperature-controlled water tank in an embodiment of the system of the present invention.

[0026] Figure 3 Schematic diagram of a hybrid cold storage evaporator in an embodiment of the system of the present invention.

[0027] Figure 4 Schematic diagram of a plate-fin phase-change cold storage device in an embodiment of the system of the present invention. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0029] The embodiment of the present invention provides a laser thermal management system using a hybrid cold storage evaporator, such as Figure 1 As shown, it includes a first water pump, a laser, a temperature-controlled water tank, a heating wire, a second water pump, a hybrid cold storage evaporator, a variable frequency pump, a compressor, a condenser, an expansion valve, a radiator and a fan; wherein the temperature-controlled water tank is as shown Figure 2 As shown, the temperature-controlled water tank is provided with four openings, namely, a hot side inlet 1, a hot side outlet 2, a cold side inlet 3 and a cold side outlet 4; the hot side outlet 2 of the temperature-controlled water tank is connected to the first water pump, the first water pump is connected to the laser through a pipeline, and then connected to the hot side inlet 1 of the temperature-controlled water tank through a pipeline after the laser; the cold side outlet 4 of the temperature-controlled water tank is connected to the inlet of the mixed cold storage evaporator, and the outlet of the mixed cold storage evaporator is connected to the cold side inlet 3 of the temperature-controlled water tank via a variable frequency pump; one end of the radiator is connected to the inlet of the mixed cold storage evaporator via the second water pump, and the outlet of the mixed cold storage evaporator is connected to the other end of the radiator through a pipeline; in addition, a condenser is installed in front of the radiator, the output of the condenser is connected to the expansion valve, the expansion valve is connected to the compressor, and the output of the compressor is connected to the input of the condenser; a pressure valve is screwed on the upper part of the temperature-controlled water tank, and the pressure valve ensures that the system is not over-pressurized; a heating wire is added to the bottom of the temperature-controlled water tank to realize the electric heating function.

[0030] In the system of the present invention, a variable frequency pump is used to adjust the flow rate and then control the temperature of the temperature-controlled water tank. Compared with the valve adjustment method, a valve is omitted, and the power of the variable frequency pump is adjustable, saving power consumption; the hybrid cold storage evaporator adopts a mixed form of phase change cold storage and sensible heat cold storage to reduce the cold storage volume. Phase change materials have been widely used in energy storage and thermal control systems. They are suitable for phase change materials for thermal management of high-power devices in the aviation field. They have wide phase change temperature (50-100°C), high latent heat, high specific heat, high thermal conductivity, good environmental adaptability, small phase change volume change, reversible phase change process, small supercooling, good chemical stability, no corrosion, no toxicity, not easy to burn, no explosion, etc.

[0031] Furthermore, the hybrid cold storage evaporator integrates the cold storage device and the evaporator to reduce the volume. In this embodiment, the hybrid cold storage evaporator integrates the liquid sensible heat cold storage, the phase change latent heat cold storage and the refrigeration evaporator into one, and the evaporator adopts a coil structure. Figure 3 As shown, it includes a plate-fin phase-change cold storage device 5 and a refrigerant coil 6. The plate-fin phase-change cold storage device is as shown in FIG. Figure 4 As shown, the plate-fin phase-change cold storage device 5 is made of aluminum alloy, including a phase-change material side 51 and a water side 52; the phase-change material side 51 uses serrated or rectangular fins to enhance heat transfer; the upper part of the plate-fin phase-change cold storage device 5 is designed with a phase-change material filling port 53, which is sealed after about 97% of the liquid is filled to prevent leakage; the phase-change cold storage device uses solid-liquid phase-change materials as cold storage media, and to ensure the efficiency of the refrigeration cycle, the temperature of the phase-change materials is 15-20°C, such as pure substances such as n-tetradecane, octanoic acid, polyethylene glycol and their eutectic mixtures. The cold storage material can provide continuous cold in a short time and play a role in stabilizing the cold output.

[0032] Furthermore, the temperature-controlled water tank includes a water tank shell 7 and an internal heat exchange coil 8, and a hot fluid is disposed outside the heat exchange coil 8. The traditional plate exchanger and the water tank are combined into one through the coil structure, which reduces the volume and increases the heat exchange area.

[0033] The present invention also provides a management method for a laser thermal management system using a hybrid cold storage evaporator, comprising the following steps:

[0034] Start-up preparation stage: When the ambient temperature is between -40 and 24°C, the laser does not work, the first water pump works, and the system preheats the heat source and the antifreeze in the temperature-controlled water tank to 25±1°C through the electric heating wire. When the ambient temperature is between 26 and 50°C, the first water pump, the frequency conversion pump, the second water pump, and the fan work, and the refrigeration cycle works to cool the temperature-controlled water tank to 25±1°C and the outlet temperature of the cold storage evaporator to 16°C.

[0035] Laser working stage: The laser generates heat. When the ambient temperature is between -40 and +5°C, the first water pump works to cool the heat source, and the coolant returns to the temperature-controlled water tank. The variable frequency pump works at a variable speed according to the temperature of the temperature-controlled water tank. The coolant absorbs heat from the outlet of the variable frequency pump through the temperature-controlled water tank and then heats up. It then cools down after the cold storage evaporator and then returns to the variable frequency pump to keep the temperature of the temperature-controlled water tank at 25±1°C. At the same time, when the outlet temperature of the hot side of the cold storage evaporator is higher than 16°C, the second water pump starts, and part of the coolant flows through the second water pump, the cold storage evaporator, and the radiator to transfer heat from the cold storage to the radiator. The fan rotates to take away the heat. The fan works at a variable speed according to the temperature of the hot side outlet of the cold storage. The higher the temperature of the hot side outlet, the faster the speed.

[0036] After the laser is turned on, the laser generates heat. When the ambient temperature is between 5 and +50°C, the first water pump works to cool the heat source, and the coolant returns to the temperature-controlled water tank. The variable frequency pump works at a variable speed according to the temperature of the temperature-controlled water tank. The coolant absorbs heat from the outlet of the variable frequency pump through the temperature-controlled water tank and then heats up. It then cools down after the cold storage evaporator and then returns to the variable frequency pump to keep the temperature of the temperature-controlled water tank at 25±1°C. At the same time, when the outlet temperature of the hot side of the cold storage evaporator is higher than 16°C, the refrigeration cycle works, and the fan rotates to take away the heat. The compressor and the fan work at a variable speed according to the temperature of the hot side outlet of the cold storage evaporator. The higher the temperature of the hot side outlet, the faster the speed.

[0037] After the laser is turned off, when the ambient temperature is between -40 and 5°C: the first water pump works, and the coolant returns to the temperature-controlled water tank through the laser. Due to the heat generated by the first water pump, the temperature of the temperature-controlled water tank will slowly rise. The variable frequency pump changes speed according to the temperature of the temperature-controlled water tank to keep the temperature of the temperature-controlled water tank at 25±1°C. The second water pump and the fan continue to work, and the coolant flows through the second water pump, the cold storage evaporator, and the radiator, transferring the heat of the cold storage evaporator to the environment until the outlet temperature of the hot side of the cold storage evaporator is less than 16°C. The fan changes speed according to the temperature of the hot side outlet of the cold storage evaporator. The higher the temperature of the hot side outlet, the faster the speed.

[0038] After the laser is turned off, when the ambient temperature is between 5 and +50°C: the first water pump, frequency conversion pump, refrigeration cycle and fan work. The refrigeration cycle cools the temperature-controlled water tank to 25±1°C and the outlet temperature of the cold storage evaporator to 16°C.

[0039] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser thermal management system using a hybrid cold storage evaporator, characterized in that: It includes a first water pump, a laser, a temperature-controlled water tank, a heating wire, a second water pump, a hybrid cold storage evaporator, a frequency conversion pump, a radiator and a fan; wherein the temperature-controlled water tank is provided with four openings, namely a hot side inlet, a hot side outlet, a cold side inlet and a cold side outlet; the hot side outlet of the temperature-controlled water tank is connected to the first water pump, the first water pump is connected to the laser through a pipeline, and the hot side inlet of the temperature-controlled water tank is connected to the laser through a pipeline; the cold side outlet of the temperature-controlled water tank is connected to the inlet of the hybrid cold storage evaporator, and the outlet of the hybrid cold storage evaporator is connected to the cold side inlet of the temperature-controlled water tank through the frequency conversion pump; one end of the radiator is connected to the inlet of the hybrid cold storage evaporator through the second water pump, and the outlet of the hybrid cold storage evaporator is connected to the other end of the radiator through a pipeline; the fan is arranged next to the radiator; the heating wire is arranged at the bottom of the temperature-controlled water tank to realize the electric heating function.

2. The system according to claim 1, characterized in that The hybrid cold storage evaporator integrates liquid sensible heat storage, phase change latent heat storage and refrigeration evaporator, and the evaporator adopts a coil structure.

3. The system according to claim 2, characterized in that The hybrid cold storage evaporator includes a plate-fin phase change cold storage device and a refrigerant coil; the plate-fin phase change cold storage device is made of aluminum alloy material, including a phase change material side and a water side; the phase change material side adopts serrated or rectangular fins to enhance heat transfer; a phase change material filling port is designed on the upper part of the plate-fin phase change cold storage device, and the liquid state is filled with about 97% and then sealed.

4. The system according to claim 3, characterized in that ,Phase change cold storage uses solid-liquid phase change materials as cold storage medium, and the temperature of the phase change material is 15-20℃.

5. The system according to any one of claims 1 to 4, characterized in that A condenser is installed in front of the radiator, the condenser output is connected to the expansion valve, the expansion valve is connected to the compressor, and the compressor output is connected to the condenser input; the pressure valve is turned on the top of the temperature-controlled water tank, and the pressure valve ensures that the system is not over-pressurized.

6. The system according to any one of claims 1 to 4, characterized in that The temperature-controlled water tank includes a water tank shell and an internal heat exchange coil, and the outside of the heat exchange coil is a hot fluid.

7. A management method for a laser thermal management system using a hybrid cold storage evaporator according to any one of claims 1 to 6, comprising the following steps: Start-up preparation stage: When the ambient temperature is between -40 and 24°C, the laser does not work, the first water pump works, and the system preheats the heat source and the antifreeze in the temperature-controlled water tank to 25±1°C through the electric heating wire; when the ambient temperature is between 26 and 50°C, the first water pump, the variable frequency pump, the second water pump, and the fan work, and the refrigeration cycle works to cool the temperature-controlled water tank to 25±1°C and the outlet temperature of the cold storage evaporator to 16°C; Laser working stage: The laser generates heat. When the ambient temperature is between -40 and +5°C, the first water pump works to cool the heat source. The coolant returns to the temperature-controlled water tank. The variable frequency pump changes speed according to the temperature of the temperature-controlled water tank. The coolant absorbs heat from the outlet of the variable frequency pump through the temperature-controlled water tank and then heats up. It then cools down after the cold storage evaporator and then returns to the variable frequency pump to keep the temperature of the temperature-controlled water tank at 25±1°C. At the same time, when the outlet temperature of the hot side of the cold storage evaporator is higher than 16°C, the second water pump starts, and part of the coolant flows through the second water pump, the cold storage evaporator, and the radiator to transfer the heat from the cold storage to the radiator. The fan rotates to take away the heat. After the laser is turned on, the laser generates heat. When the ambient temperature is between 5 and +50°C, the first water pump works to cool the heat source, and the coolant returns to the temperature-controlled water tank. The variable frequency pump works at a variable speed according to the temperature of the temperature-controlled water tank. The coolant absorbs heat from the outlet of the variable frequency pump through the temperature-controlled water tank and then heats up. It then cools down after passing through the cold storage evaporator, and then returns to the variable frequency pump to keep the temperature of the temperature-controlled water tank at 25±1°C. At the same time, when the outlet temperature of the hot side of the cold storage evaporator is higher than 16°C, the refrigeration cycle works, and the fan rotates to take away the heat. After the laser is turned off, when the ambient temperature is between -40 and 5°C: the first water pump works, and the coolant returns to the temperature-controlled water tank through the laser; the variable frequency pump changes speed according to the temperature of the temperature-controlled water tank to keep the temperature of the temperature-controlled water tank at 25±1°C; the second water pump and fan continue to work, and the coolant flows through the second water pump, the cold storage evaporator, and the radiator, transferring the heat of the cold storage evaporator to the environment until the outlet temperature of the hot side of the cold storage evaporator is less than 16°C; After the laser is turned off, when the ambient temperature is between 5 and +50°C: the first water pump, frequency conversion pump, refrigeration cycle and fan work. The refrigeration cycle cools the temperature-controlled water tank to 25±1°C and the outlet temperature of the cold storage evaporator to 16°C.

Images