A refrigeration and heating system and method based on heat gas bypass of a vortex tube

Abstract

The application discloses a kind of based on vortex tube hot gas bypass refrigeration, heating system and method, system includes parallel refrigeration branch and heating branch, refrigeration branch is equipped with vortex tube and second regenerator, vortex tube hot gas outlet is connected second regenerator by bypass branch with second regulating valve;Heating branch is equipped with heating tube;First regenerator is arranged at gas source input end, and its back gas port is connected test area backflow loop.Cooling when conducting refrigeration branch, vortex tube working pressure is regulated to optimum value by pressure sensor and first regulating valve closed loop, and bypass hot gas flow is regulated to target temperature by temperature sensor and second regulating valve closed loop, and cold and hot gas is mixed into test area after second regenerator;Heating when conducting heating branch, after being heated by heating tube, it is sent into test area;Backflow gas in two modes is all heat exchanged with import gas by first regenerator and recovers excess cold or waste heat.The application realizes the consideration of rapid cooling and accurate temperature control, and improves system energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of combined refrigeration and heating systems, and in particular to a refrigeration and heating system and method based on vortex tube hot gas bypass. Background Technology

[0002] Currently, the industry primarily relies on heat flow meters for rapid temperature cycling testing of small electronic devices. Heat flow meters use compressed air to generate hot and cold airflows through vortex tubes, which are then directly applied to the device under test. They offer fast temperature response and high temperature change rates, making them the mainstream technology that balances heating / cooling speed with temperature control accuracy. However, existing vortex tube heat flow meters have the following drawbacks in practical applications: Firstly, although vortex tubes have no moving parts and a compact structure, the existing systems control their working pressure in a rather crude manner, usually by manual adjustment or fixed value control. This causes the vortex tubes to easily deviate from their optimal working pressure point during actual operation, resulting in a significant decrease in cooling efficiency. This manifests as an unstable cooling rate and the inability to reach the design value for the lower limit of low temperature. To compensate for the insufficient efficiency of vortex tubes, it is often necessary to increase the gas supply pressure or increase the gas supply flow rate, which indirectly increases the requirements for gas source equipment and pipeline size. Secondly, when vortex tubes are used for cooling, the cold end outlet temperature is usually lower than the target temperature control temperature. In order to obtain an accurate test temperature, existing technologies generally adopt a cold-heat counteraction method. That is, the vortex tube is first cooled to generate a supercooled cold airflow, and then the supercooled gas is heated again by the heating tube to offset the excess coldness, so that the output temperature reaches the target value. Although this cold-heat counteraction temperature control method can achieve accurate temperature control, it causes a lot of energy waste. The power consumption required by the heating tube and the cooling power consumption required for cooling exist at the same time, and the system energy efficiency ratio is extremely low. Third, existing eddy tube heat flow meters typically discharge the return gas from the outlet of the device under test directly in the gas path design, without recovering or utilizing the residual cold or heat carried in the return gas, which further exacerbates energy loss. In summary, existing eddy tube heat flow meters struggle to balance size, cost, cooling rate, temperature control accuracy, and energy efficiency. There is an urgent need for a temperature control solution that is compact, cools rapidly, controls temperature precisely, and is highly energy efficient. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art in vortex tube heat flow meters, such as reduced cooling efficiency and unstable cooling rate due to the coarse pressure control causing the vortex tube to deviate from the optimal operating point; large amount of energy waste caused by the cold and heat confrontation method of temperature control by first supercooling and then electric heating to offset the cold and heat; and low system energy efficiency by directly discharging the return gas without recovering the waste cold or heat it carries. The present invention provides a refrigeration and heating system and method based on vortex tube hot gas bypass, which can maintain the vortex tube at the optimal operating pressure through pressure closed-loop control to ensure efficient cooling and rapid cooling. The hot gas flow generated by the vortex tube itself is introduced into the hot gas bypass branch to mix with the cold gas flow for heat exchange to achieve precise temperature regulation without additional electric heating. The waste cold or heat of the return gas is recovered through the first regenerator to improve the overall energy efficiency of the system.

[0004] To solve the above-mentioned technical problems, the present invention provides a refrigeration and heating system based on vortex tube hot gas bypass, comprising: Gas source input terminal, first regenerator, pressure regulating branch, first diversion node, refrigeration branch, hot gas bypass branch, heating branch, second diversion node, temperature sensor, test area, return gas circuit and control system; The pressure regulating branch is connected to the outlet of the first regenerator and includes a first regulating valve and a pressure sensor connected in sequence. The inlet of the first diversion node is connected to the pressure regulating branch, and its two outlets are connected to the refrigeration branch through the first solenoid valve and to the heating branch through the second solenoid valve, respectively. The refrigeration branch includes a vortex tube and a second regenerator connected sequentially along the airflow direction. The cold air outlet of the vortex tube flows directly into the second regenerator, and the hot air outlet of the vortex tube is connected to the bypass inlet of the second regenerator through the hot air bypass branch equipped with a second regulating valve. The heating branch includes a heating element; The two inlet ends of the second diversion node are respectively connected to the outlet ends of the cooling branch and the heating branch, and its outlet ends are sequentially connected to the temperature sensor and the test area. The temperature sensor is used to collect the temperature of the gas delivered to the test area. The return gas circuit is connected between the test area and the first regenerator, and is used to introduce the return gas into the first regenerator for heat exchange. The control system is connected to the first regulating valve, the second regulating valve, the first solenoid valve, the second solenoid valve, the pressure sensor, the temperature sensor, and the heating element.

[0005] In one embodiment of the present invention, the hot gas bypass branch further includes a silencer disposed at the hot gas outlet of the vortex tube, the silencer being used to reduce airflow noise during hot gas discharge.

[0006] In one embodiment of the present invention, a one-way valve is provided between the second regenerator and the second diversion node. The one-way valve is used to restrict the airflow to flow unidirectionally from the refrigeration branch and the heating branch to the second diversion node.

[0007] In one embodiment of the present invention, both the first regulating valve and the second regulating valve are electrically operated regulating valves, and both the first solenoid valve and the second solenoid valve are normally closed solenoid valves.

[0008] To address the aforementioned technical problems, this invention also provides a refrigeration and heating method based on vortex tube hot gas bypass, applied to the aforementioned refrigeration system based on vortex tube hot gas bypass, comprising: The cooling mode control steps include: Connect the cooling branch and disconnect the heating branch; Set the target cooling temperature T0 and the optimal working pressure P0, collect the system pressure P through the pressure sensor, and adjust the opening of the first regulating valve with PID control to make P = P0. High-pressure gas enters the vortex tube through the first regenerator and is separated into cold gas and hot gas. Part of the hot gas is discharged and part of it bypasses the second regulating valve and enters the second regenerator. The outlet temperature T of the second regenerator is collected, and the opening of the second regulating valve is adjusted by PID control to control the bypass hot gas flow rate, so that the cold gas flow and the bypass hot gas are mixed and exchanged in the second regenerator until T = T0. The temperature-controlled gas is sent to the test area, and the return gas is discharged after recovering residual heat through the first regenerator. The heating mode control steps include: Connect the heating branch and disconnect the cooling branch; The target heating temperature T0' is set, and the gas enters the heating tube through the first regenerator. After being heated to T0', it is sent to the test area. The return gas is discharged after recovering its residual heat through the first regenerator.

[0009] In one embodiment of the present invention, in the cooling mode control step, the optimal working pressure P0 is set to 0.6 MPa by default, and the minimum temperature of the cooling target temperature T0 is set to -20°C.

[0010] In one embodiment of the present invention, in the cooling mode control step, the deviation between the outlet temperature T of the second regenerator and the target cooling temperature T0 is controlled within ±0.5℃.

[0011] In one embodiment of the present invention, in the heating mode control step, the optimal working pressure P0 is set to 0.3 MPa by default, and the maximum temperature of the heating target temperature T0' is set to 65°C.

[0012] In one embodiment of the present invention, in the heating mode control step, the heating power of the heating tube is adjusted by PID according to the difference between the heating target temperature T0' and the actual temperature of the gas after preheating by the first regenerator.

[0013] In one embodiment of the present invention, when switching from the cooling mode to the heating mode, the second regulating valve is first closed, and after a delay, the on / off state of the first solenoid valve and the second solenoid valve is switched; when switching from the heating mode to the cooling mode, the heating element is first closed, and after a delay, the on / off state of the first solenoid valve and the second solenoid valve is switched.

[0014] The technical solution of the present invention has the following advantages compared with the prior art: The refrigeration and heating system and method based on vortex tube hot gas bypass described in this invention achieves precise control of the vortex tube's operating pressure by setting up a pressure regulation branch, avoiding the decrease in cooling efficiency and unstable cooling rate caused by pressure deviation from the optimal point. Simultaneously, by utilizing the vortex tube hot gas bypass to the second regenerator for heat exchange with the cold gas flow, it replaces the traditional hot-cold confrontation method, effectively reducing energy waste and improving temperature control accuracy and system energy efficiency. Furthermore, the combination of the return gas loop and the first regenerator enables the recovery and utilization of residual cold or heat from the return gas, further enhancing the overall energy efficiency of the system. Therefore, this system provides a compact, rapid cooling, precise temperature control, and excellent energy efficiency temperature control solution for rapid temperature cycling testing of small electronic devices. Attached Figure Description

[0015] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of the cooling and heating system based on vortex tube hot gas bypass of the present invention; Figure 2 This is a flowchart of the steps of the cooling and heating method based on vortex tube hot gas bypass of the present invention.

[0016] Explanation of reference numerals in the accompanying drawings: 1. Gas source input terminal; 2. First regenerator; 3. Pressure regulating branch; 301. First regulating valve; 302. Pressure sensor; 4. First branch node; 5. Refrigeration branch; 501. First solenoid valve; 502. Swirl tube; 503. Second regenerator; 6. Hot gas bypass branch; 601. Second regulating valve; 602. Silencer; 7. Heating branch; 701. Second solenoid valve; 702. Heating tube; 8. Second branch node; 9. Temperature sensor; 10. Test area; 11. Return gas circuit; 12. Control system; 13. Check valve. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0018] Reference Figure 1 As shown, this invention provides a cooling and heating system based on vortex tube hot gas bypass. The gas path architecture features a parallel cooling branch 5 and a heating branch 7. Cooling branch 5 uses a vortex tube 502 as the core cold source component, while heating branch 7 uses a heating tube 702 as the core heat source component. At the first branch node 4, the system can quickly switch between cooling and heating modes according to testing requirements by switching between a first solenoid valve 501 and a second solenoid valve 701. Cooling and heating of the test area 10 are achieved respectively through the second branch node 8. Compared to existing heat flow meters that rely on high-power compressor units for gas supply, the vortex tube 502 of this invention has no moving parts and only requires compressed gas to generate a cooling effect. This hardware aspect determines the system's advantages in size and weight.

[0019] In terms of pressure control, this system sequentially sets up a first regenerator 2 and a pressure regulating branch 3 between the gas source input 1 and the vortex tube 502. The pressure regulating branch 3 includes a first regulating valve 301 and a pressure sensor 302. The cooling efficiency of the vortex tube 502 is closely related to its operating pressure. Deviating from the optimal operating pressure will lead to a decrease in the cold end temperature drop of the vortex tube 502 and a decrease in the coefficient of performance (COP). This invention collects the system pressure in real time through the pressure sensor 302 and feeds it back to the control system 12. The control system 12 automatically adjusts the opening of the first regulating valve 301 through a PID algorithm, so that the vortex tube 502 is always maintained near the preset optimal operating pressure. No matter how the upstream gas source pressure fluctuates, the vortex tube 502 can stably operate in the high-efficiency range. Compared with the crude pressure control method in the prior art, this closed-loop pressure control method ensures that the vortex tube 502 maintains a high cooling efficiency under different operating conditions, fundamentally guaranteeing the stability of the system cooling rate and the reliability of the low temperature limit, and avoiding the drawbacks of increasing the gas supply pressure and flow rate to compensate for insufficient efficiency.

[0020] Regarding temperature control, this invention abandons the existing method of first supercooling and then electrically heating to offset the temperature difference, and instead adopts a hot gas bypass mixing temperature regulation strategy. Specifically, a hot gas bypass branch 6 is set between the hot gas outlet of the vortex tube 502 and the bypass inlet of the second regenerator 503, and a second regulating valve 601 is installed on this branch. The high-pressure cold gas flow and hot gas flow generated by the vortex tube 502 originally exist simultaneously and are mutually complementary. Existing technologies usually directly discharge the hot gas flow as waste heat, and only use the cold gas flow and supplement it with electric heating to adjust the temperature. This is essentially an energy-wasting temperature control path. This invention draws a portion of the hot gas flow from the hot end of the vortex tube 502, and after the flow rate is controlled by the second regulating valve 601, it enters the second regenerator 503, with some of the hot gas flow being discharged. The hot gas flow entering the second regenerator 503 mixes and exchanges heat with the main cold gas flow. Fine-tuning of the cold gas output temperature can be achieved by adjusting the flow rate of the hot gas bypass – increasing the bypass hot gas flow when a slightly higher temperature is needed, and decreasing the bypass hot gas flow when a slightly lower temperature is needed. The entire temperature adjustment process requires no additional electric heating power. A temperature sensor 9 is installed on the pipeline between the second diversion node 8 and the test zone 10 to collect the temperature of the temperature-controlled gas about to enter the test zone 10 in real time. The control system 12 uses the deviation between this temperature value and the target temperature as input, and adjusts the opening of the second regulating valve 601 through a PID algorithm to form a closed-loop temperature control.

[0021] In summary, the control strategy of this invention can be described as a dual-closed-loop cascade control consisting of a pressure closed loop and a hot gas bypass: the pressure closed loop, as the inner loop, ensures that the vortex tube 502 itself operates in its optimal state, while the temperature closed loop, as the outer loop, utilizes the hot gas flow generated by the vortex tube 502 itself as the regulating medium to achieve precise adjustment of the output temperature. This control strategy directly solves the energy waste problem caused by the contrast between hot and cold in the prior art. Furthermore, the response speed of hot gas bypass regulation is faster than that of electric heating regulation, which helps to improve the dynamic response performance of temperature control.

[0022] In terms of energy recovery, this invention includes a first regenerator 2 and a return gas circuit 11. The return gas circuit 11 reintroduces the return gas flowing out of the test zone 10 into the first regenerator 2, where it exchanges heat with the fresh, dry gas flowing in from the gas source input terminal 1. In cooling mode, the gas returning from the test zone 10 still carries a certain amount of cold energy, which is wasted in the prior art by being directly discharged into the atmosphere. This invention transfers the residual cold energy of the return gas to the dry gas on the intake side through the first regenerator 2, thereby reducing the intake temperature before entering the vortex tube 502, thus reducing the cooling temperature difference required by the vortex tube 502 and improving the utilization efficiency of the unit cooling capacity. In heating mode, the system switches and cuts off the cooling branch 5 and connects the heating branch 7 through a solenoid valve. The gas is heated by the heating tube 702 and then sent into the test zone 10. The high-temperature return gas is also preheated by the first regenerator 2, reducing the temperature rise required by the heating tube 702 and reducing the power consumption of electric heating. The introduction of the first regenerator 2 enables the system to achieve cascaded energy recovery and utilization in both cooling and heating modes, further improving the overall energy efficiency of the system.

[0023] In summary, this invention solves the cooling rate problem by ensuring the efficient operation of the vortex tube 502 through pressure closed-loop control, solves the energy efficiency and temperature control accuracy problems by replacing the hot-cold confrontation through hot gas bypass mixing temperature regulation, and solves the energy waste problem by recovering the waste cold and heat of the return gas through the first regenerator 2. The three technical means are independent of each other and synergistically enhance each other, and simultaneously achieve rapid cooling, precise temperature control and high energy efficiency operation in a compact system architecture.

[0024] In some of the above embodiments, the system utilizes a vortex tube 502 for cooling or heating, wherein the hot gas outlet of the vortex tube 502 discharges high-temperature, high-pressure gas. However, the discharge of such high-speed airflow is often accompanied by significant airflow noise, which may not only interfere with operators but also affect the overall operating environment of the equipment, reducing the comfort and applicability of the system.

[0025] In this regard, this application further proposes that the hot gas bypass branch 6 also includes a silencer 602 disposed at the hot gas outlet of the vortex tube 502, the silencer 602 being used to reduce airflow noise during hot gas discharge.

[0026] The silencer 602 is a device specifically designed to attenuate airflow noise. Its basic principle is to convert sound energy into heat energy or other forms of energy through mechanisms such as sound absorption, impedance mismatch, or resonance, thereby effectively reducing noise propagation. Specifically, the silencer 602 can adopt various structural forms. For example, it can be a resistive silencer filled with porous sound-absorbing material. When airflow passes through, sound waves rub against the tiny pores of the material, dissipating energy and achieving noise reduction. Alternatively, it can be a reactive silencer, which utilizes the reflection and interference of sound waves to attenuate noise by incorporating structures such as expansion cavities and resonant cavities. A composite silencer combining the above two principles can also be used to achieve wider frequency band noise control. The silencer 602 is strategically positioned at the hot gas outlet of the vortex tube 502, i.e., in the hot gas bypass branch 6, to ensure effective treatment of the generated high-speed airflow noise before the hot gas is discharged or bypassed into the second regenerator 503.

[0027] In some embodiments described above, both the cooling branch 5 and the heating branch 7 are connected to the second branch node 8 to deliver the temperature-controlled gas to the test area 10. However, in actual operation, especially during system mode switching or when one branch is working while the other is off, backflow or reverse flow may occur, leading to uneven gas mixing, affecting the temperature stability and control accuracy of the test area 10, and potentially causing unnecessary pressure fluctuations or damage to system components.

[0028] In this regard, this application further proposes that a one-way valve 13 be provided between the second regenerator 503 and the second diversion node 8. The one-way valve 13 is used to restrict the airflow to flow unidirectionally from the refrigeration branch 5 and the heating branch 7 to the second diversion node 8.

[0029] A one-way valve 13, also known as a check valve, is a valve that automatically prevents fluid from flowing backward. Its working principle typically relies on the pressure difference of the fluid itself. When the forward pressure reaches a certain value, the valve opens to allow fluid to pass through; when the reverse pressure increases or the forward pressure decreases, the valve automatically closes, effectively preventing fluid backflow. In practical applications, the one-way valve 13 can adopt various structural forms, such as lift, swing, butterfly, or ball types. For gas systems, a one-way valve 13 with good sealing performance and low pressure drop is usually selected to ensure system efficiency. For example, a spring-loaded lift one-way valve 13 can be used. Its valve core is normally in the closed state under the action of the spring force. Only when the gas pressure from the refrigeration branch 5 or the heating branch 7 overcomes the spring force is the valve core opened, allowing gas to flow to the second branch node 8. Once the airflow stops or the pressure on the second branch node 8 side is higher than that on the branch side, the spring force will quickly reset the valve core, achieving a reliable seal and preventing any form of backflow.

[0030] In this embodiment, the first regulating valve 301 and the second regulating valve 601 are configured as electrically controlled regulating valves, meaning that these valves can precisely control their opening degree by receiving electrical signals. Electrically controlled regulating valves are typically driven by an electric actuator, which includes a motor, a reducer, and a position feedback device, enabling continuous and proportional adjustment of the valve opening degree. This control method allows the system to finely control the gas flow rate by issuing corresponding electrical signals through the control system 12 (e.g., a PID controller) based on feedback signals from the pressure sensor 302 and the temperature sensor 9, thereby achieving precise regulation of the system pressure and the bypass hot gas flow rate.

[0031] Meanwhile, configuring the first solenoid valve 501 and the second solenoid valve 701 as normally closed solenoid valves means that these solenoid valves are in a closed state when not energized, preventing gas flow. When the control system 12 needs to switch between the refrigeration branch 5 and the heating branch 7, the corresponding solenoid valve is energized to open it, thereby allowing gas to flow. This design ensures that the valves automatically close when the system loses power or the control signal is lost, ensuring the system remains in a safe state. Normally closed solenoid valves typically consist of an electromagnetic coil, valve body, valve core, and return spring, opening by overcoming spring force with electromagnetic force.

[0032] Reference Figure 2 As shown, this application also discloses a refrigeration and heating method based on vortex tube hot gas bypass, applied to the above-mentioned refrigeration system based on vortex tube hot gas bypass, including: The cooling mode control steps include: Connect the cooling branch 5 and disconnect the heating branch 7; Set the target cooling temperature T0 and the optimal working pressure P0. Collect the system pressure P through the pressure sensor 302. Adjust the opening of the first regulating valve 301 using PID control to make P = P0. High-pressure gas enters the vortex tube 502 through the first regenerator 2 and is separated into cold gas and hot gas. Part of the hot gas is discharged and part of it bypasses the second regulating valve 601 and enters the second regenerator 503. The outlet temperature T of the second regenerator 503 is collected, and the opening of the second regulating valve 601 is adjusted by PID control to control the bypass hot gas flow rate, so that the cold gas flow and the bypass hot gas are mixed and exchanged in the second regenerator 503 until T = T0. The temperature-controlled gas is sent to the test area 10, and the return gas is discharged after recovering residual heat through the first regenerator 2. The heating mode control steps include: Connect the heating branch 7 and disconnect the cooling branch 5; The target heating temperature T0' is set, and the gas enters the heating tube 702 through the first regenerator 2. After being heated to T0', it is sent to the test area 10. The return gas is discharged after recovering the residual heat through the first regenerator 2.

[0033] Traditional vortex tube 502 heat flow meters suffer from technical problems in temperature cycling tests of small electronic devices, including coarse working pressure control leading to decreased cooling efficiency, energy waste due to heat-cold counterbalancing in temperature control, and unrecovered residual cold from the return gas. The core innovation of this embodiment lies in combining precise PID pressure regulation with hot gas bypass mixing heat exchange in a synergistic manner, thereby avoiding energy loss from heat-cold counterbalancing and improving the system's energy efficiency ratio and temperature control accuracy. Specifically, in cooling mode, the system monitors the gas path pressure in real time through pressure sensor 302, and the control system 12PID adjusts the opening of the first regulating valve 301 to ensure that the vortex tube 502 always operates stably at the optimal working pressure P0, maximizing its cooling efficiency. Simultaneously, a portion of the hot gas flow generated by the vortex tube 502 bypasses to the second regenerator 503 via the second regulating valve 601, directly mixing and exchanging heat with the cold gas flow, replacing the traditional secondary heating method and eliminating energy waste from heat-cold counterbalancing.

[0034] Furthermore, in the cooling mode control step, the outlet temperature T of the second regenerator 503 is precisely controlled by adjusting the opening of the second regulating valve 601 through PID control, ensuring that the mixed gas temperature stably reaches the target cooling temperature T0, thus avoiding temperature control deviations caused by temperature fluctuations. When the return gas returns to the first regenerator 2 via the return gas loop 11, the residual heat it carries is used to pre-cool the incoming gas, significantly reducing the overall energy consumption of the system. In the heating mode, the gas enters the heating tube 702 after being preheated by the first regenerator 2, is heated to the target temperature T0', and then sent to the test area 10. The residual heat in the return gas is also recovered and utilized through the first regenerator 2, further optimizing energy efficiency.

[0035] Through the above technical solution, the system eliminates the need for additional electric heating to offset subcooling during the cooling process. It directly utilizes the hot gas bypass of the vortex tube 502 to achieve fine-tuning of the temperature, significantly reducing power consumption. Simultaneously, the dual regenerator design enables tiered recovery of cooling and heating, effectively utilizing the residual cooling and heat of the return gas. Overall, this method significantly improves the system's energy efficiency ratio while ensuring rapid cooling and high temperature control accuracy, resolving the inherent contradiction between size, cost, and energy efficiency in existing technologies.

[0036] In some embodiments described above, a cooling and heating method based on hot gas bypass of a vortex tube 502 is proposed. The cooling mode control steps involve setting the target cooling temperature T0 and the optimal operating pressure P0, and achieving precise temperature and pressure control through PID regulation. However, in practical applications, without preset or clearly defined ranges for these key parameters, the system may require repeated debugging and empirical adjustments by the operator when starting up or switching to cooling mode to achieve the best cooling effect and efficiency. This undoubtedly increases the complexity of operation and may prolong the time required for the system to reach a stable operating state.

[0037] In this regard, this application further proposes that in the cooling mode control step, the default optimal working pressure P0 is set to 0.6MPa, and the minimum temperature of the cooling target temperature T0 is set to -20℃.

[0038] Specifically, the default optimal operating pressure P0 is set to 0.6 MPa, meaning that when the system enters cooling mode, the control system 12 will automatically set the target pressure to 0.6 MPa. This optimal operating pressure P0 is a value that, after system design and experimental verification, enables the vortex tube 502 to achieve high efficiency during energy separation. The system pressure P is collected by the pressure sensor 302, and the control system 12 adjusts the opening of the first regulating valve 301 using a PID algorithm to stabilize the actual system pressure P at 0.6 MPa. This preset value helps ensure that the vortex tube 502 operates near-optimal conditions from startup, thereby rapidly generating a low-temperature cold airflow.

[0039] Meanwhile, the minimum temperature for the target cooling temperature T0 is set to -20℃, clearly defining the lowest temperature limit achievable by the system in cooling mode. This means that in scenarios requiring low-temperature testing, such as performing low-temperature performance testing on optical modules at -20℃, the system can stably provide and maintain this temperature. This minimum temperature setting is based on the cold air temperature generated by the vortex tube 502 at an operating pressure of 0.6MPa, combined with the comprehensive effect of heat exchange after the cold airflow and bypass hot airflow are mixed in the second regenerator 503. This limitation provides a clear indicator of the system's performance in specific application scenarios.

[0040] In some embodiments described above, the flow rate of bypass hot gas is controlled by adjusting the opening of the second regulating valve 601 using PID control, thereby mixing and exchanging heat with the bypass hot gas in the second regenerator 503 to reach the target cooling temperature T0. However, in practical applications, due to fluctuations in ambient temperature, changes in gas source pressure, and the inherent operating characteristics of the vortex tube 502, accurately and stably controlling the gas temperature within a very small error range to meet the stringent temperature requirements of the test area 10 remains a challenge.

[0041] To address this, this application further proposes that, in the cooling mode control step, the deviation between the outlet temperature T of the second regenerator 503 and the target cooling temperature T0 is controlled within ±0.5℃. This means that the system has extremely high control accuracy requirements for the gas temperature delivered to the test area 10 in cooling mode. Specifically, when the system sets a target cooling temperature T0, the actual measured outlet temperature T of the second regenerator 503 must always be maintained within the range of T0 minus 0.5℃ to T0 plus 0.5℃. Achieving this high-precision control typically requires the synergistic effect of the following aspects: First, a temperature sensor 9 with fast response speed and high measurement accuracy is used to acquire the outlet temperature T of the second regenerator 503 in real time and accurately, providing a reliable feedback signal to the control system 12. Second, adaptive PID, fuzzy PID, or feedforward-feedback combined control strategies can be adopted to optimize the PID control algorithm, improve the robustness and dynamic response capability of the control system 12, and ensure high-precision temperature control under various operating conditions. Furthermore, the second regulating valve 601, as a key actuator for controlling the bypass hot gas flow, needs to possess high resolution, rapid response, and precise adjustment capabilities to respond to minute adjustment commands issued by the control system 12, thereby achieving fine control of the mixing heat exchange process. In addition, the design of the entire refrigeration branch 5 and the hot gas bypass branch 6 should consider airflow stability, heat exchange efficiency, and minimizing external interference. For example, by optimizing the pipe layout and selecting a high-efficiency regenerator, a stable physical basis can be provided for high-precision temperature control.

[0042] In the aforementioned cooling and heating method based on hot gas bypass of the vortex tube 502, the heating mode control step heats the gas to the preset heating target temperature T0' via the heating tube 702 before sending it to the test area 10. However, if key operating parameters in the heating process, such as the optimal working pressure and the upper limit of the heating target temperature, are not clearly defined, the system may operate under suboptimal conditions, affecting heating efficiency and energy consumption. Furthermore, excessively high temperatures or unsuitable pressures may potentially damage the tested optical modules and other equipment, thus limiting the system's stability and reliability in specific application scenarios.

[0043] In this regard, this application further proposes that in the heating mode control step, the optimal working pressure P0 is set to 0.3MPa by default, and the maximum temperature of the heating target temperature T0' is set to 65℃.

[0044] Specifically, in heating mode, the system requires a stable operating pressure to ensure the effective operation of the heating element 702 and the stability of the gas flow. The optimal operating pressure P0 refers to an ideal operating pressure point set while ensuring system performance and efficiency. It is set to a default value of 0.3 MPa, based on a comprehensive consideration of system design, the characteristics of the heating element 702, the gas medium, and the target application (such as optical module testing). A lower pressure (e.g., 0.3 MPa) helps reduce system energy consumption while avoiding unnecessary stress on the heating element 702 and sensitive equipment within the test area 10 due to excessive pressure. This pressure value is typically determined through experimental verification or theoretical calculation to optimize overall system efficiency and safety while ensuring sufficient heat exchange capacity. Meanwhile, the target heating temperature T0' is the gas temperature that the system needs to achieve in heating mode. Setting its maximum temperature to 65°C ensures that the tested equipment (e.g., optical modules) will not be damaged by excessive temperature during heating. Many electronic components and optical modules have clearly defined upper limits for their operating temperature ranges; exceeding these ranges may lead to performance degradation, shortened lifespan, or even permanent damage. Limiting the maximum temperature to 65°C provides a safety margin, ensuring the system effectively protects the device under test (DUT) while meeting testing requirements. This upper limit is typically determined with reference to industry standards, component specifications, or specific testing requirements.

[0045] Specifically, the heating power of the heating tube 702 is PID-regulated based on the difference between the target heating temperature T0' and the actual temperature of the gas after preheating by the first regenerator 2. In this embodiment, the heating tube 702 is the core component in the heating branch 7, and its function is to heat the flowing gas to the required temperature. The heating power refers to the amount of heat transferred by the heating tube 702 to the gas per unit time, which is usually adjusted by controlling the input voltage, current, or energizing time of the heating tube 702. For example, when the heating tube 702 is an electric heating tube, its output power can be precisely controlled by adjusting its supply voltage or by using pulse width modulation (PWM) technology. The target heating temperature T0' is the gas temperature that the system expects to achieve in the heating mode. This temperature is preset according to the specific requirements of the test area 10 for the gas temperature and is the reference value for temperature adjustment by the control system 12. In the heating mode, the return gas enters the first regenerator 2 through the return gas circuit 11 and exchanges heat with the gas about to enter the heating tube 702, thereby preheating the gas entering the heating tube 702. The actual temperature of the gas after preheating by the first regenerator 2 refers to the real-time temperature of the gas after heat exchange in the first regenerator 2 before entering the heating tube 702. This temperature varies due to factors such as the return gas temperature, flow rate, and heat exchange efficiency of the first regenerator 2. The temperature difference refers to the difference between the target heating temperature T0' and the actual temperature of the gas after preheating by the first regenerator 2. This difference reflects the additional heat required by the heating tube 702 to raise the preheated gas to the target temperature. It is one of the input signals of the PID controller, used to measure the deviation between the current temperature and the target temperature. In this application, the PID controller calculates and outputs an adjustment command for the heating power of the heating tube 702 in real time based on the difference between the target heating temperature T0' and the actual temperature of the gas after preheating by the first regenerator 2.

[0046] In practical applications, the system needs to switch between two operating modes (cooling and heating). Failure to implement orderly and coordinated control of key actuators in the system may lead to drastic fluctuations in internal pressure or temperature, thereby affecting the stable operation of the equipment, shortening component lifespan, and even causing unnecessary energy loss. For example, when switching from cooling mode to heating mode, if the hot gas bypass branch 6 of the vortex tube 502 is not closed in time, the hot gas flow may interfere with the airflow of the heating branch 7; conversely, when switching from heating mode to cooling mode, if the heating tube 702 is not stopped in time, it may cause unnecessary energy consumption or adversely affect the subsequent cooling process.

[0047] To address this, this application further proposes a mode switching control strategy. When the system switches from cooling mode to heating mode, the second regulating valve 601 is closed first. The second regulating valve 601 is a key component located on the hot gas bypass branch 6 at the hot gas outlet of the vortex tube 502, used to control the bypass volume of the hot gas flow separated from the vortex tube 502. Closing it means cutting off the bypass path of the hot gas flow from the vortex tube 502 to the second regenerator 503, thereby ensuring that no hot gas flow enters or stagnates in the bypass branch when the cooling mode ends. This operation can prevent residual hot gas flow from interfering with the system or causing unnecessary pressure fluctuations after switching to heating mode. After closing the second regulating valve 601, the control system 12 performs a delay operation. This delay refers to a waiting time reserved before executing the subsequent solenoid valve switching action. This delay is designed to allow sufficient time for the airflow and pressure state inside the system to stabilize and adjust after the second regulating valve 601 is closed, avoiding instantaneous pressure shocks or imbalances caused by excessively rapid operation. After the delay ends, the control system 12 switches the on / off state of the first solenoid valve 501 and the second solenoid valve 701. The first solenoid valve 501 controls the on / off state of the cooling branch 5, and the second solenoid valve 701 controls the on / off state of the heating branch 7. By switching their on / off states, the cooling branch 5 can be closed and the heating branch 7 can be opened, thereby completing the transition from cooling mode to heating mode.

[0048] Similarly, when the system switches from heating mode to cooling mode, the first step is to shut down the heating element 702. The heating element 702 is the core component of the heating branch 7, responsible for heating the gas. Shutting it off means stopping the gas heating process, thus preventing energy waste caused by the heating element 702 continuing to operate after switching to cooling mode, or sending high-temperature gas into the cooling branch 5, negatively impacting the cooling effect. After shutting down the heating element 702, the control system 12 also performs a delay. This delay allows residual heat from the heating element 702 to dissipate and the gas temperature in the heating branch 7 to gradually decrease, while allowing sufficient time for the airflow and pressure states inside the system to stabilize. This helps avoid thermal shock or mechanical stress to system components due to sudden temperature changes or pressure instability when switching to cooling mode. After the delay, the control system 12 then switches the on / off states of the first solenoid valve 501 and the second solenoid valve 701. By switching their on / off states, the heating branch 7 can be turned off and the cooling branch 5 can be turned on, thereby completing the transition from heating mode to cooling mode.

[0049] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A refrigeration and heating system based on vortex tube hot gas bypass, characterized in that, include: Gas source input terminal, first regenerator, pressure regulating branch, first diversion node, refrigeration branch, hot gas bypass branch, heating branch, second diversion node, temperature sensor, test area, return gas circuit and control system; The pressure regulating branch is connected to the outlet of the first regenerator and includes a first regulating valve and a pressure sensor connected in sequence. The inlet of the first diversion node is connected to the pressure regulating branch, and its two outlets are connected to the refrigeration branch through the first solenoid valve and to the heating branch through the second solenoid valve, respectively. The refrigeration branch includes a vortex tube and a second regenerator connected sequentially along the airflow direction. The cold air outlet of the vortex tube flows directly into the second regenerator, and the hot air outlet of the vortex tube is connected to the bypass inlet of the second regenerator through the hot air bypass branch equipped with a second regulating valve. The heating branch includes a heating element; The two inlet ends of the second diversion node are respectively connected to the outlet ends of the cooling branch and the heating branch, and its outlet ends are sequentially connected to the temperature sensor and the test area. The temperature sensor is used to collect the temperature of the gas delivered to the test area. The return gas circuit is connected between the test area and the first regenerator, and is used to introduce the return gas into the first regenerator for heat exchange. The control system is connected to the first regulating valve, the second regulating valve, the first solenoid valve, the second solenoid valve, the pressure sensor, the temperature sensor, and the heating element.

2. The refrigeration and heating system based on vortex tube hot gas bypass according to claim 1, characterized in that: The hot gas bypass branch also includes a silencer installed at the hot gas outlet of the vortex tube, which is used to reduce airflow noise during hot gas discharge.

3. The refrigeration and heating system based on vortex tube hot gas bypass according to claim 1, characterized in that: A one-way valve is provided between the second regenerator and the second diversion node. The one-way valve is used to restrict the airflow to flow only in one direction from the refrigeration branch and the heating branch to the second diversion node.

4. The refrigeration and heating system based on vortex tube hot gas bypass according to claim 1, characterized in that: Both the first regulating valve and the second regulating valve are electrically operated regulating valves, and both the first solenoid valve and the second solenoid valve are normally closed solenoid valves.

5. A refrigeration and heating method based on vortex tube hot gas bypass, applied to the refrigeration system based on vortex tube hot gas bypass as described in any one of claims 1 to 4, characterized in that: include: The cooling mode control steps include: Connect the cooling branch and disconnect the heating branch; Set the target cooling temperature T0 and the optimal working pressure P0, collect the system pressure P through the pressure sensor, and adjust the opening of the first regulating valve with PID control to make P = P0. High-pressure gas enters the vortex tube through the first regenerator and is separated into cold gas and hot gas. Part of the hot gas is discharged and part of it bypasses the second regulating valve and enters the second regenerator. The outlet temperature T of the second regenerator is collected, and the opening of the second regulating valve is adjusted by PID control to control the bypass hot gas flow rate, so that the cold gas flow and the bypass hot gas are mixed and exchanged in the second regenerator until T = T0. The temperature-controlled gas is sent to the test area, and the return gas is discharged after recovering residual heat through the first regenerator. The heating mode control steps include: Connect the heating branch and disconnect the cooling branch; The target heating temperature T0' is set, and the gas enters the heating tube through the first regenerator. After being heated to T0', it is sent to the test area. The return gas is discharged after recovering its residual heat through the first regenerator.

6. The cooling and heating method based on vortex tube hot gas bypass according to claim 5, characterized in that: In the cooling mode control steps, the default setting for the optimal working pressure P0 is 0.6 MPa, and the minimum temperature of the target cooling temperature T0 is set to -20℃.

7. The refrigeration and heating method based on vortex tube hot gas bypass according to claim 5, characterized in that: In the cooling mode control step, the deviation between the outlet temperature T of the second regenerator and the target cooling temperature T0 is controlled within ±0.5℃.

8. The cooling and heating method based on vortex tube hot gas bypass according to claim 5, characterized in that: In the heating mode control steps, the default setting of the optimal working pressure P0 is 0.3MPa, and the maximum temperature of the heating target temperature T0' is set to 65℃.

9. The cooling and heating method based on vortex tube hot gas bypass according to claim 5, characterized in that: In the heating mode control step, the heating power of the heating tube is adjusted by PID according to the difference between the heating target temperature T0' and the actual temperature of the gas after preheating by the first regenerator.

10. The cooling and heating method based on vortex tube hot gas bypass according to claim 5, characterized in that: When switching from the cooling mode to the heating mode, the second regulating valve is closed first, and after a delay, the on / off state of the first solenoid valve and the second solenoid valve is switched; when switching from the heating mode to the cooling mode, the heating element is closed first, and after a delay, the on / off state of the first solenoid valve and the second solenoid valve is switched.

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