A cooling device based on tunnel wall surface and a control method thereof

Abstract

This invention relates to the field of tunnel cooling, and discloses a cooling device and control method based on the tunnel wall, including a water tank, a variable frequency water pump, a pipe network, a first circulating water pump, a second circulating water pump, an air-to-water heat exchanger, and a control unit; the pipe network is located between the tunnel inner wall and the lining structure layer. In this solution, the variable frequency water pump draws cooling water from the water tank into the pipe network for heat exchange, cooling the inner wall of the tunnel. The heated water is then sent to the air-to-water heat exchanger through a second water pipe to exchange heat with the outside air, becoming cooling water, and then flowing back to the water tank through a third water pipe, forming a closed loop. Furthermore, a temperature sensor monitors the tunnel temperature, and a data processing unit calculates and controls the flow rate controller to control the speed of the variable frequency water pump, thus controlling the flow rate of the cooling water to achieve cooling of the tunnel inner wall with low energy consumption.

Description

Technical Field

[0001] This invention relates to the field of tunnel cooling, specifically to a cooling device based on the tunnel wall and its control method. Background Technology

[0002] In high-temperature tunnels or underground engineering projects, traditional cooling technologies mainly rely on mechanical ventilation or spray systems, but these methods have significant drawbacks. Mechanical ventilation is inefficient, air has a small heat capacity, requires a large air volume to achieve effective cooling, and consumes extremely high energy. Spray evaporative cooling consumes a large amount of water resources, easily causing lining corrosion, and its applicability is limited in arid regions. Indirect cooling solutions using cooling towers can alleviate high temperatures, but they have drawbacks such as large footprint, high risk of scaling, and freezing problems in cold regions. In addition, existing closed-loop systems mostly rely on large heat exchange equipment, which are complex in structure and have high maintenance costs. Summary of the Invention

[0003] The purpose of this invention is to provide a cooling device based on the tunnel wall, which solves the problems of high water consumption and heavy reliance on large heat exchange equipment in traditional cooling technologies.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a cooling device based on the tunnel wall, comprising a water tank, a variable frequency water pump, a pipe network, a first circulating water pump, a second circulating water pump, an air-water heat exchanger, and a control unit;

[0005] The pipeline network is installed between the tunnel wall and the lining structure layer;

[0006] The water tank is connected to one end of the pipe network through the first water supply pipe, and the other end of the pipe network is connected to one end of the air-water heat exchanger through the second water supply pipe. The other end of the air-water heat exchanger is connected to the water tank through the third water supply pipe.

[0007] An air-water heat exchanger is installed outside the tunnel, a variable frequency water pump is installed on the first water supply pipe, a first circulating water pump is installed on the second water supply pipe, and a second circulating water pump is installed on the third water supply pipe.

[0008] The control unit includes a temperature sensor, a flow rate controller, and a data processing unit; the temperature sensor is installed inside the tunnel wall; the flow rate controller and the data processing unit are used to control the speed of the variable frequency water pump.

[0009] As a further technical solution to the above scheme, the pipeline is arranged in a double helix shape between the inner wall of the tunnel and the lining structure layer.

[0010] As a further technical solution to the above scheme, the inner wall of the pipeline network is coated with a nano anti-scaling coating.

[0011] A control method for a cooling device based on tunnel wall, comprising:

[0012] Step S1: The data processing unit has a built-in historical heat load database; set the target temperature. Temperature sensor collects wall temperature The clock records the current time. ;

[0013] Step S2, based on the current time The predicted heat load coefficient for the current moment is obtained through the historical heat conformity database. Calculate the base flow velocity The formula is as follows:

[0014] ;

[0015] In the formula, Preset the flow rate for the system. Preset gain;

[0016] Step S3, calculate the real-time temperature error The PID algorithm is used to calculate the real-time corrected flow rate. The formula is as follows:

[0017] ;

[0018] In the formula, This is the proportionality coefficient; The integral coefficient; These are the differential coefficients;

[0019] Step S4: Perform gradient pressurization determination, and monitor the temperature error in real time. and its changes:

[0020] like If the set emergency threshold is not exceeded, the rated flow rate will be maintained. :

[0021] ;

[0022] like If the temperature exceeds the set emergency threshold, it is determined to be a sudden thermal shock. At this point, the speed of the variable frequency water pump is increased, and the input of cooling water is increased until the temperature reaches a certain level. Below Introducing a decay factor Calculate low-velocity flow rate The formula is as follows:

[0023] ;

[0024] low flow rate The signal is sent to the flow rate controller to adjust the speed of the variable frequency water pump.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] By installing a variable frequency water pump, cooling water in the water tank is pumped into the pipe network for heat exchange, cooling the inner wall of the tunnel. The heated water is then sent to an air-water heat exchanger through a second water pipe to exchange heat with the outside air. After becoming cooling water, it flows back to the water tank through a third water pipe, forming a closed loop. Furthermore, the temperature of the tunnel is monitored by a temperature sensor, and the flow rate controller is used by a data processing unit to control the speed of the variable frequency water pump and the flow rate of the cooling water, thus achieving the cooling operation of the inner wall of the tunnel with low energy consumption. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of this device.

[0028] Figure 2 This is a schematic diagram of the tunnel structure.

[0029] Figure 3 This is a flowchart illustrating the process of this solution.

[0030] The meanings of the labels in the diagram are as follows:

[0031] Water tank-1; Control unit-2; Variable frequency water pump-3; Tunnel inner wall-4; Lining structure layer-5; Pipeline network-6; First circulating water pump-7; Air-water heat exchanger-8; Second circulating water pump-9; Temperature sensor-10; Flow rate controller-11; Data processing unit-12; First water supply pipe-13; Second water supply pipe-14; Third water supply pipe-15. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, so as to provide a better understanding of the concept of the present invention, the technical problem solved, the technical features constituting the technical solution, and the technical effects brought about.

[0033] like Figures 1-3 As shown, a cooling device based on tunnel wall includes a water tank 1, a variable frequency water pump 3, a pipe network 6, a first circulating water pump 7, a second circulating water pump 9, an air-water heat exchanger 8 (a device that allows water to exchange heat indirectly with air to achieve air heating / cooling or water heating / cooling, where the two media do not come into direct contact) and a control unit 2.

[0034] Pipeline 6 is installed between the tunnel inner wall 4 and the lining structure layer 5;

[0035] Water tank 1 is connected to one end of pipe network 6 through first water supply pipe 13, and the other end of pipe network 6 is connected to one end of air-water heat exchanger 8 through second water supply pipe 14. The other end of air-water heat exchanger 8 is connected to water tank 1 through third water supply pipe 15.

[0036] An air-water heat exchanger 8 is installed outside the tunnel, a variable frequency water pump 3 is installed on the first water supply pipe 13, a first circulating water pump 7 is installed on the second water supply pipe 14, and a second circulating water pump 9 is installed on the third water supply pipe 15.

[0037] The control unit 2 includes a temperature sensor 10, a flow rate controller 11, and a data processing unit 12; the temperature sensor 10 is installed inside the wall of the tunnel inner wall 4; the flow rate controller 11 and the data processing unit 12 are used to control the speed of the variable frequency water pump 3.

[0038] During tunnel cooling, a pipe network 6 is installed between the tunnel inner wall 4 and the lining structure layer 5. The pipe network 6 and the air-water heat exchanger 8 serve as the heat exchange structure. Overall, it is a closed-loop water circulation module and an air-water heat exchange module. In the closed-loop water circulation module, the temperature of the tunnel wall is monitored by the temperature sensor 10. The flow rate of cooling water in the water tank 1 to the pipe network 6 embedded between the tunnel inner wall 4 and the lining structure layer 5 is controlled by adjusting the speed of the variable frequency water pump 3. The cooling water in the pipe network 6 absorbs heat from the tunnel wall, and the temperature of the cooling water rises from T1 to T2. It is then transported to the air-water heat exchanger 8 by the first circulating water pump 7 for cooling. After the air-water heat exchanger 8 exchanges with the outside cold air, the temperature drops from T2 to T3. It then flows back to the water tank 1 by the second circulating water pump 9 to complete the closed-loop circulation. Figure 1 The solid line represents cooling water, and the dashed line represents high-temperature water. The air-water heat exchange module is arranged on the outer wall of the tunnel and is connected to the closed water circulation module through heat exchange pipelines such as the first water supply pipe 13, the second water supply pipe 14, and the third water supply pipe 15. It is used to discharge the heat absorbed by the water circulation module in the form of dry air.

[0039] The control unit 2 includes a temperature sensor 10, a flow rate controller 11, and a data processing unit 12. The temperature sensor 10 is embedded in the tunnel wall, and the data processing unit 12 dynamically adjusts the speed of the variable frequency water pump 3 according to the temperature data.

[0040] In a preferred embodiment, the pipeline network 6 is arranged in a double helix shape between the tunnel inner wall 4 and the lining structure layer 5. In this embodiment, the pipeline network 6 is arranged in a double helix parallel structure between the tunnel inner wall 4 and the lining structure layer 5 during pre-embedding, which utilizes the large-area heat dissipation advantage of the lining without damaging the original load-bearing structure of the tunnel.

[0041] In a preferred embodiment, the inner wall of the pipe network 6 is coated with a nano-scale anti-scaling coating. In this embodiment, the nano-scale anti-scaling coating on the inner wall of the pipe network 6, combined with a closed-loop pure water circulation, eliminates the persistent problem of scaling and clogging in traditional water cooling systems, significantly reducing the frequency of pipe cleaning and maintenance costs.

[0042] A control method for a cooling device based on tunnel wall, comprising:

[0043] Step S1: The data processing unit 12 has a built-in historical heat load database; a target temperature is set. Temperature sensor 10 collects the wall temperature The clock records the current time. ;

[0044] Step S2, based on the current time The predicted heat load coefficient for the current moment is obtained from the historical heat load database. Calculate the base flow velocity The formula is as follows:

[0045] ;

[0046] In the formula, Preset the flow rate for the system. Preset gain;

[0047] Step S3, calculate the real-time temperature error The PID algorithm is used to calculate the real-time corrected flow rate. The formula is as follows:

[0048] ;

[0049] In the formula, This is the proportionality coefficient; The integral coefficient; These are the differential coefficients;

[0050] Step S4: Perform gradient pressurization determination, and monitor the temperature error in real time. and its changes:

[0051] like If the set emergency threshold is not exceeded, the rated flow rate will be maintained. :

[0052] ;

[0053] like If the temperature exceeds the set emergency threshold, it is determined to be a sudden thermal shock. At this time, the speed of the variable frequency water pump 3 is increased, and the input of cooling water is increased until the temperature reaches a certain level. Below Introducing a decay factor Calculate low-velocity flow rate The formula is as follows:

[0054] ;

[0055] low flow rate The signal is sent to the flow rate controller 11 to adjust the speed of the variable frequency water pump 3.

[0056] When using this device, the data processing unit has a built-in adaptive control program that simulates a thermodynamic response model. First, the average temperature of the wall surface is collected via temperature sensor 10; then, feedforward control is implemented. The system internally stores a historical heat load database, which records the typical heat load coefficients of the tunnel in different seasons and at different times. The projected heat load coefficient at the current moment is calculated using a periodic function. The system calculates the baseline flow rate. For example, at noon when the outside temperature is high and traffic is heavy, the system can increase the pump speed in advance based on historical experience, without waiting for the temperature to rise before reacting.

[0057] Feedback control is also required during use to calculate the real-time temperature difference error. Furthermore, the flow rate is corrected using a PID algorithm (Proportional, Integral, Differential). By handling real-time fluctuations, the temperature is ensured to be precisely stable at the set value. Under these conditions, the equipment operates normally in a cycle, and the flow rate is maintained. .

[0058] To further ensure the normal operation of the system, gradient boosting determination is also required, and the system needs to monitor errors in real time. and its rate of change, if If the temperature exceeds the set emergency threshold (e.g., 2.0℃), it is determined to be a sudden thermal shock. In this case, the normal PID output is ignored, and a powerful boost value is directly added to the total output. (For example, increase the rated power by 30%) until the temperature drops.

[0059] When the system is in steady state and Below Within a certain range (e.g., 0.5°C below the required temperature, in a "supercooled" state), the system activates energy-saving mode. An attenuation factor is introduced. (For example, 0.95), reduce the total output instructions: At this time It is a real-time correction of the flow rate, and every current moment. Related, but different. Principle explanation: The system continuously attempts to reduce the pump speed; as long as the temperature doesn't rebound excessively, it continues to decrease, thus approaching the system's minimum energy consumption boundary. Ultimately, it will... Send it to flow controller 11 for control.

[0060] The core function of the proportional gain is to provide a control correction based on the magnitude of the real-time temperature error; the larger the error, the greater the correction. The larger the corresponding output correction value, the faster it can respond to temperature deviations, which is the fundamental adjustment element of PID control. In this scheme, when the actual temperature of the tunnel wall... With target temperature temperature difference The larger, The higher the value, the higher the water pump speed will be, and the faster the cooling water circulation will be to enhance cooling.

[0061] The core function of the integral gain is to eliminate the static error of the system, particularly temperature error. By performing time integration, the problem of proportional control being able to only respond to real-time errors and unable to address long-term, small deviations is compensated for. In this scheme, if the tunnel wall temperature remains slightly higher than the target temperature for an extended period (a small, persistent deviation),... The integral value will continue to accumulate, gradually increasing the control output until the deviation is completely eliminated, ensuring that the temperature is accurately and stably maintained at the set value.

[0062] The core function of the differential gain is to predict the deviation trend in advance based on the rate of change of temperature error, thereby suppressing temperature fluctuations. The derivative reflects the rate of change of the deviation, allowing for advance adjustments to avoid temperature overshoot or drastic fluctuations. Corresponding to this invention: if the tunnel wall temperature rises rapidly within a short period of time ( (Large number) It will quickly provide correction values, increase the water pump speed in advance, prevent the temperature difference from expanding further, and improve the stability of the system.

[0063] This is the system's preset flow rate, measured in m³ / h or L / min.

[0064] The proportionality coefficient is set at 0.8–1.2 for conventional high-temperature tunnels; 1.5–2.0 for rock-thermal tunnels; and 1.0–1.5 for cold-region tunnels.

[0065] General values ​​for integral coefficients: 0.05~0.2; for high-precision temperature tunnels: 0.15~0.2; for low-precision tunnels: 0.05~0.1;

[0066] The differential coefficients are set at 0.3–0.5 for tunnels with large traffic flow fluctuations or sudden thermal shock, and 0.1–0.2 for conventional tunnels.

[0067] The preset gain values ​​are: Summer / Peak Season: 1.3–1.5; Winter / Off-Season: 1.0–1.2; Spring and Autumn: 1.1–1.3.

[0068] The heat load coefficient ranges from 0 to 2.0 (nighttime / low traffic: 0.3 to 0.8; daytime / high traffic: 1.2 to 1.8; extreme high temperature: 2.0).

[0069] The general emergency temperature threshold is 2.0℃ (activated at e≥2℃); 1.5℃ for rock thermal tunnels; and 2.0~3.0℃ for conventional tunnels.

[0070] The general supercooling threshold is -0.5℃ (start-up at e≤-0.5℃); -0.3℃ for high-precision tunnels; and -1.0℃ for low-requirement tunnels.

[0071] The general value for the attenuation factor is 0.95; 0.90 for fast energy-saving tunnels; and 0.97–0.98 for temperature-stable tunnels.

[0072] The general value for booster compensation is 30% of the rated power; 40%–50% for rock thermal tunnels; and 20%–30% for conventional tunnels.

[0073] Compared with the prior art, the present invention has significant advantages:

[0074] 1. Eliminate temperature control lag and achieve proactive response (corresponding to feedforward control strategy).

[0075] Traditional tunnel temperature control often employs a "threshold trigger" mode (i.e., activation only after temperature rises), which often exhibits significant lag when dealing with the enormous heat capacity of the surrounding rock. This invention innovatively introduces a feedforward control mechanism based on historical data, capable of predicting heat load trends according to time periods (such as day / night or season). Before a heat wave arrives (e.g., before the daily temperature peak), the system proactively increases the base flow velocity, effectively overcoming the challenge of high thermal inertia in tunnels and minimizing temperature fluctuations.

[0076] 2. Extreme energy saving, actively seeking the lowest energy consumption point (corresponding to the energy consumption optimization module).

[0077] Unlike traditional variable frequency systems that can only passively adjust based on temperature differences, this invention possesses an "active optimization" capability. When the system is operating in steady state and the temperature meets the target (within the supercooled range), the algorithm automatically and gradually attempts to reduce the water pump speed by introducing a decay factor. This "trial and error" control logic allows the system to consistently approach the physical minimum energy consumption boundary required to maintain the target temperature without sacrificing cooling performance, achieving energy savings of over 30% compared to traditional constant temperature control.

[0078] 3. Equipped with gradient boost function and strong resistance to thermal shock (corresponding to gradient boost mode).

[0079] To address sudden extreme high temperatures or surges in heat load, this invention employs a gradient boosting logic. Once the rate of temperature rise or error exceeds an emergency threshold, the system immediately bypasses conventional PID control, superimposes a powerful boosting command, and forces the water pump to operate at over-rated power. This nonlinear response mechanism ensures the safety of tunnel equipment and structures under extreme conditions.

[0080] 4. Closed-loop system with zero water consumption and excellent environmental adaptability.

[0081] The fully enclosed water circulation design completely solves the problems of water waste and tunnel lining corrosion caused by spray cooling technology.

[0082] Adaptability to arid regions: Zero evaporation water consumption, making it particularly suitable for arid regions with scarce water resources;

[0083] Cold region adaptability: With the help of ethylene glycol antifreeze medium and intelligent low flow rate circulation mode, it can still operate in a -30℃ environment without freezing;

[0084] Structural protection: Pre-embedded pipes and high-efficiency heat exchangers prevent corrosion of tunnel electrical equipment and metal components by high humidity air.

[0085] 5. Extend equipment lifespan and reduce operation and maintenance costs

[0086] Soft start and smooth adjustment: PID-based frequency conversion control avoids the mechanical shock (water hammer effect) caused by frequent pump start-stop, significantly extending the life of the motor and pipeline.

[0087] Anti-scaling design: The inner wall of the pipe network is coated with a nano anti-scaling coating, combined with a closed-loop pure water circulation system, which eliminates the stubborn problem of scale buildup and blockage in traditional water cooling systems, and significantly reduces the frequency of pipe cleaning and maintenance costs.

[0088] 6. Flexible construction, does not affect the structural safety of the tunnel.

[0089] The pre-buried pipeline network adopts a double-helix parallel structure arranged between the secondary lining and the primary support, which not only utilizes the heat dissipation advantage of the large area of ​​the lining, but also does not damage the original load-bearing structure of the tunnel. The heat exchanger is modularly designed and can be flexibly installed at the tunnel entrance or ventilation shaft without the need for additional land acquisition and construction of large cooling towers.

[0090] The terms "connection" and "fixing" appearing in the description of this invention can refer to fixed connection, processing and forming, welding, or mechanical connection. The specific meaning of the above terms in this invention should be understood according to the specific circumstances.

[0091] In the description of this invention, the terms "center," "upper," "lower," "horizontal," "inner," and "outer," etc., are used only to indicate the orientation or positional relationship for the convenience of describing this invention and to simplify the description, and do not indicate or imply a specific orientation that the device or element referred to must have, and therefore should not be construed as a limitation of this invention.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cooling device based on tunnel wall, characterized in that: It includes a water tank (1), a variable frequency water pump (3), a pipe network (6), a first circulating water pump (7), a second circulating water pump (9), an air-water heat exchanger (8), and a control unit (2); The pipeline (6) is located between the inner wall (4) of the tunnel and the lining structure layer (5); The water tank (1) is connected to one end of the pipe network (6) through the first water supply pipe (13), and the other end of the pipe network (6) is connected to one end of the air-water heat exchanger (8) through the second water supply pipe (14). The other end of the air-water heat exchanger (8) is connected to the water tank (1) through the third water supply pipe (15). An air-water heat exchanger (8) is installed outside the tunnel, a variable frequency water pump (3) is installed on the first water supply pipe (13), a first circulating water pump (7) is installed on the second water supply pipe (14), and a second circulating water pump (9) is installed on the third water supply pipe (15). The control unit (2) includes a temperature sensor (10), a flow rate controller (11), and a data processing unit (12); the temperature sensor (10) is installed inside the wall of the tunnel inner wall (4); the flow rate controller (11) and the data processing unit (12) are used to control the speed of the variable frequency water pump (3).

2. The cooling device based on the tunnel wall according to claim 1, characterized in that: The pipeline (6) is arranged in a double helix shape between the inner wall (4) of the tunnel and the lining structure layer (5).

3. The tunnel wall surface-based cooling device according to claim 1, characterized in that: The inner wall of the pipeline (6) is coated with a nano anti-scaling coating.

4. The control method of the tunnel wall surface-based cooling device according to any one of claims 1 to 3, characterized by: Includes the following steps: Step S1, the data processing unit (12) is built-in historical heat load database; set up target temperature , temperature sensor (10) collects wall temperature , clock records current time ; Step S2, based on the current time The predicted heat load coefficient for the current moment is obtained from the historical heat load database. Calculate the base flow velocity The formula is as follows: ； In the formula, is a preset flow rate of the system, is a preset gain; Step S3, calculating real-time temperature error calculating real-time correction flow rate by PID algorithm The formula is as follows: ； wherein is a proportional coefficient; is an integral coefficient; is a derivative coefficient; Step S4, gradient pressure increase determination is performed, and the system monitors the temperature error in real time and variations thereof, like If the set emergency threshold is not exceeded, the rated flow rate will be maintained. : ； like If the set emergency threshold is exceeded, it is determined to be a sudden thermal shock. At this time, the speed of the variable frequency water pump (3) is increased, and the input of cooling water is increased until the temperature reaches a certain level. Below Introducing a decay factor Calculate low-velocity flow rate The formula is as follows: ； The low flow rate is sent to the flow rate controller (11) to adjust the rotation speed of the variable frequency water pump (3).

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