A cooling and dehumidifying system and method for an underground cable tunnel

Abstract

The present application relates to cable tunnel environment control technical field, disclose a kind of underground cable tunnel cooling and dehumidification system and method, the input end of the system is connected to river water intake, and the input river water is shunted by water distribution unit into two branches, one is transported to radiation cooling unit, and the whole sensible heat cooling is realized by the direct heat exchange between pipe wall and tunnel air;Another is transported to air conditioning dehumidification unit, and the deep dehumidification and auxiliary cooling of tunnel air are completed by cooperating refrigeration compression unit, while the condensation waste heat generated by refrigeration compression unit is taken away by river water;The backwater after heat exchange of two roads is unified into water collection unit, and finally discharged to river drain outlet;The system makes full use of river free cooling source to bear main heat load, only start mechanical refrigeration when dehumidification demand is insufficient, effectively solve the technical defects of insufficient cooling capacity, high energy consumption and missing dehumidification function in prior art, while ensuring that tunnel temperature and humidity meet the standard, prolong the service life of equipment, significantly reduce operating energy consumption.

Description

Technical Field

[0001] This invention relates to the field of environmental control technology for cable tunnels, and in particular to a cooling and dehumidification system and method for underground cable tunnels. Background Technology

[0002] The heat load in underground cable tunnels increases significantly with the increase of cable current carrying capacity. Controlling the thermal environment inside the tunnel is a key technical aspect to ensure power transmission safety and equipment lifespan.

[0003] Currently, environmental control in underground cable tunnels primarily employs a ventilation and cooling system combining natural air intake and mechanical exhaust. Some projects supplement this with indirect water cooling solutions, such as laying cooling water pipes on the tunnel roof, or direct cooling solutions, such as bundling the cable body with circulating cooling water pipes, to address the heat dissipation demands generated during cable operation. However, under ultra-high voltage levels and high current loads, the heat generated by the cables increases dramatically, and the heat dissipation capacity of traditional ventilation systems is gradually approaching its limit. To maintain the tunnel temperature below the safe threshold of 40°C, ventilation systems often need to operate continuously with high air volumes, which not only leads to a surge in operating energy consumption but also easily results in problems such as excessive exhaust temperature and temperature control failure under harsh conditions such as high summer temperatures and ultra-long tunnels. This, in turn, accelerates cable insulation aging, reduces cable current carrying capacity, and threatens the safe and stable operation of the power transmission system. At the same time, underground cable tunnels in southern my country generally suffer from persistent high humidity. High humidity not only deteriorates sanitary conditions within the tunnel but also shortens the lifespan of electrical instruments and monitoring equipment, thereby increasing operation and maintenance costs.

[0004] Southern regions have the advantage of abundant water resources, and a large number of cable tunnels are laid along or through rivers. The water temperature of rivers is stable all year round and is generally lower than the air temperature inside the tunnels, which has the potential to be used as a free natural low-temperature cold source. However, existing technologies have not yet formed a systematic solution for utilizing river cold sources that is suitable for the narrow arc space of cable tunnels and takes into account both cooling and dehumidification needs, making it difficult to fully realize the energy-saving value of natural cold sources.

[0005] In summary, existing cable tunnel cooling technologies suffer from deficiencies such as insufficient cooling capacity, high operating energy consumption, weak environmental control stability, and lack of dehumidification function. They are no longer able to meet the growing demand for heat and humidity control in ultra-high voltage cable tunnels. Therefore, existing technologies need to be improved and enhanced. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a cooling and dehumidification system for underground cable tunnels, which can solve the technical defects of insufficient cooling capacity, high energy consumption and lack of dehumidification function in the prior art, and significantly reduce operating energy consumption while ensuring that the temperature and humidity of the tunnel meet the standards and extending the service life of the equipment.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A cooling and dehumidification system for an underground cable tunnel includes a control unit, and a water distribution unit, a radiant cooling unit, an air conditioning dehumidification unit, a refrigeration compression unit, and a water collection unit, all electrically connected to the control unit. The input end of the water distribution unit is connected to a river water intake. The output end of the water distribution unit is connected to the input ends of both the radiant cooling unit and the air conditioning dehumidification unit. The output end of the air conditioning dehumidification unit is connected to the condensate inlet of the refrigeration compression unit. The output ends of the radiant cooling unit and the condensate outlet of the refrigeration compression unit are connected to the input end of the water collection unit. The output end of the water collection unit is connected to a river drainage outlet.

[0008] The cooling and dehumidification system also includes a water intake and treatment unit electrically connected to the control unit. The input end of the water intake and treatment unit is used to connect to the river water intake, and the output end of the water intake and treatment unit is connected to the input end of the water distribution unit.

[0009] The cooling and dehumidification system also includes a water mixing and discharge unit electrically connected to the control unit. The input end of the water mixing and discharge unit is connected to the output end of the water collection unit, and the water intake end of the water mixing and discharge unit is used to connect to a river water intake.

[0010] In the cooling and dehumidification system, the mixing and discharge unit includes a mixing tank, a mixing pump, a mixing valve, a water intake temperature sensor, and a mixing temperature sensor electrically connected to the control unit. The input end of the mixing tank is connected to the output end of the water collection unit. The input end of the mixing valve is used to connect to a river water intake. The output end of the mixing valve is connected to the mixing inlet of the mixing tank through the mixing pump. The water intake temperature sensor is located on the output side of the mixing pump and is used to acquire the water temperature in the mixing tank in real time.

[0011] In the cooling and dehumidification system, the water distribution unit includes a water distributor, an inlet gate valve, and a water supply pump and an inlet water temperature sensor, which are electrically connected to the control unit. The input end of the inlet gate valve is connected to a river water intake, and the output end of the inlet gate valve is connected to the input end of the water distributor through the water supply pump. The inlet water temperature sensor is located on the outlet side of the water supply pump. The output end of the water distributor is connected to the input end of the radiant cooling unit and the input end of the air conditioning dehumidification unit.

[0012] In the cooling and dehumidification system, the radiant cooling unit includes multiple cooling water pipes and multiple branch control valves corresponding to each cooling water pipe; each branch control valve is electrically connected to the control unit; the input end of each cooling water pipe is connected to the output end of the water distributor through the corresponding branch control valve, and the output end of each cooling water pipe is connected to the input end of the water collection unit; the cooling water pipes are used for direct heat exchange with the air in the underground cable tunnel.

[0013] In the cooling and dehumidification system, the air conditioning dehumidification unit includes a chilled water coil, a bypass pipe, and a first three-way valve and a second three-way valve electrically connected to the control unit. The inlet of the first three-way valve is connected to the output of the water distributor, the two outlets of the first three-way valve are respectively connected to the input of the chilled water coil and the input of the bypass pipe, the two inlets of the second three-way valve are respectively connected to the output of the bypass pipe and the output of the chilled water coil, and the output of the second three-way valve is connected to the condensate inlet of the refrigeration compression unit.

[0014] The present invention also provides a cooling and dehumidification method for underground cable tunnels, the cooling and dehumidification method being implemented based on the cooling and dehumidification system described in any of the preceding claims, the cooling and dehumidification method comprising: acquiring a pre-constructed maintenance plan, the maintenance plan including one or more maintenance tasks; when the time difference between the trigger time of any maintenance task and the current time is ≤ a preset preparation time threshold, controlling the cooling and dehumidification system to sequentially execute a personnel maintenance mode and a heat exhaust and dehumidification mode; when the time difference between the trigger time of all maintenance tasks and the current time is > a preset preparation time threshold, controlling the cooling and dehumidification system to alternately execute a heat exhaust and dehumidification mode and a ventilation mode; when an abnormal accident occurs, controlling the cooling and dehumidification system to sequentially execute a ventilation mode, a personnel maintenance mode, and a heat exhaust and dehumidification mode.

[0015] In the aforementioned cooling and dehumidification method, controlling the cooling and dehumidification system to sequentially execute a personnel maintenance mode and a heat exhaust dehumidification mode includes: acquiring the real-time ambient temperature and relative humidity inside the underground cable tunnel, as well as the real-time water temperature of the river; controlling the cooling and dehumidification system to first execute the personnel maintenance mode, adjusting the start / stop status of the radiant cooling unit and the air conditioning dehumidification unit based on the real-time ambient temperature and the comparison result between the real-time ambient temperature and the real-time water temperature; simultaneously adjusting the start / stop status of the air conditioning dehumidification unit based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset maintenance environment temperature and humidity requirements; when the maintenance task is completed, controlling the cooling and dehumidification system to execute the heat exhaust dehumidification mode, adjusting the start / stop status of the radiant cooling unit and the air conditioning dehumidification unit based on the real-time ambient temperature, and adjusting the start / stop status of the air conditioning dehumidification unit based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset heat exhaust dehumidification operating condition requirements; when executing the personnel maintenance mode or the heat exhaust dehumidification mode, if the air conditioning dehumidification unit is in the on state, adjusting the working state of the air conditioning dehumidification unit based on the real-time water temperature.

[0016] In the cooling and dehumidification method described above, controlling the cooling and dehumidification system to alternately execute a heat exhaust dehumidification mode and a ventilation mode includes: acquiring the real-time ambient temperature and relative humidity inside the underground cable tunnel, as well as the real-time water temperature of the river; controlling the cooling and dehumidification system to first execute the heat exhaust dehumidification mode, adjusting the start / stop status of the radiant cooling unit and the air conditioning dehumidification unit based on the real-time ambient temperature, and adjusting the start / stop status of the air conditioning dehumidification unit based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset heat exhaust dehumidification operating conditions; when the air conditioning dehumidification unit is in the on state, adjusting the working state of the air conditioning dehumidification unit based on the real-time water temperature; when the preset air exchange time point is reached, controlling the cooling and dehumidification system to execute the ventilation mode according to the preset number of air exchanges.

[0017] Beneficial effects: This invention provides a cooling and dehumidification system for underground cable tunnels. Its input end connects to a river water intake. The incoming river water is divided into two branches by a water distribution unit. One branch is delivered to a radiant cooling unit, where it directly exchanges heat with the air inside the tunnel through the pipe wall to achieve overall sensible heat cooling. The other branch is delivered to an air conditioning and dehumidification unit, which, in conjunction with a refrigeration and compression unit, completes deep dehumidification and auxiliary cooling of the air inside the tunnel. Simultaneously, the river water carries away the condensation waste heat generated by the refrigeration and compression unit. The return water from both heat exchange branches flows into a collection unit and is ultimately discharged to a river drainage outlet. This system fully utilizes the free cold source of the river to bear the main heat load, only activating mechanical refrigeration when dehumidification demand is insufficient. It effectively solves the technical defects of existing technologies, such as insufficient cooling capacity, high energy consumption, and lack of dehumidification function. While ensuring that the tunnel temperature and humidity meet standards and extending equipment lifespan, it significantly reduces operating energy consumption. Attached Figure Description

[0018] Figure 1 This is a first system structure diagram of the cooling and dehumidification system provided by the present invention; Figure 2 This is a second system structure diagram of the cooling and dehumidification system provided by the present invention; Figure 3 A front sectional view of an underground cable tunnel provided for this invention; Figure 4 A lateral sectional view of an underground cable tunnel provided for this invention; Figure 5 The present invention provides a logic flowchart of the cooling and dehumidification method.

[0019] Key component symbols: 11-Water distributor, 12-Inlet gate valve, 13-Water supply pump, 14-Inlet water temperature sensor, 21-Cooling water pipe, 22-Branch control valve, 23-Condensate pan, 31-Cold water coil, 32-Bypass pipe, 33-First three-way valve, 34-Second three-way valve, 35-Air conditioning equipment, 41-Compressor, 42-Condenser, 43-Throttle valve, 44-Evaporator, 45-Fan, 51-Water collector, 52-Return water branch gate valve, 53-Return water temperature sensor, 54-Outlet check valve, 61-Filter screen, 62-Automatic backwash filter, 63-Y-type filter, 64-Inlet water control valve, 71-Mixing pump, 72-Mixing valve, 73-Inlet water temperature sensor, 74-Mixing water temperature sensor, 75-Mixing tank, 8-Ventilation fan. Detailed Implementation

[0020] This invention provides a cooling and dehumidification system and method for underground cable tunnels. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] In the description of this invention, it should be understood that the terms "installation" and "connection" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] like Figures 1 to 4As shown, the present invention provides a cooling and dehumidification system for underground cable tunnels, including a control unit, and a water distribution unit, a radiant cooling unit, an air conditioning dehumidification unit, a refrigeration compression unit, and a water collection unit, all electrically connected to the control unit. The input end of the water distribution unit is connected to a river water intake, the output end of the water distribution unit is connected to the input ends of the radiant cooling unit and the air conditioning dehumidification unit, the output end of the air conditioning dehumidification unit is connected to the condensate inlet of the refrigeration compression unit, the output end of the radiant cooling unit and the condensate outlet of the refrigeration compression unit are connected to the input end of the water collection unit, and the output end of the water collection unit is connected to a river drainage outlet.

[0023] This invention discloses a cooling and dehumidification system for underground cable tunnels. Its input end connects to a river water intake. The incoming river water is divided into two branches by a water distribution unit. One branch is delivered to a radiant cooling unit, where it directly exchanges heat with the air inside the tunnel through the pipe wall to achieve overall sensible heat cooling. The other branch is delivered to an air conditioning dehumidification unit, which, in conjunction with a refrigeration compression unit, completes deep dehumidification and auxiliary cooling of the air inside the tunnel. Simultaneously, the river water carries away the condensation waste heat generated by the refrigeration compression unit. The return water from both heat exchange branches flows into a collection unit and is ultimately discharged to a river drainage outlet. The radiant cooling unit uses natural river water as the refrigerant to handle the main sensible heat load, requiring no airflow and consuming no fan energy, making it suitable for long-term unattended tunnel scenarios. The refrigeration compression unit serves as an auxiliary cold source, handling the wet load that the chilled water coil 31 cannot cover. It only activates when dehumidification demand is insufficient, significantly reducing the operating time of mechanical refrigeration. This effectively solves the technical defects of existing technologies, such as insufficient cooling capacity, high energy consumption, and lack of dehumidification function, ensuring that the tunnel temperature and humidity meet standards and extending equipment life while significantly reducing operating energy consumption.

[0024] In this embodiment, the refrigeration compression unit includes a compressor 41, a condenser 42, a throttle valve 43, and an evaporator 44 connected in sequence via refrigerant pipelines, forming an independent closed-loop refrigeration cycle. The water collection unit uses a water collector 51 as the core for collecting return water and is equipped with gate valves 52 for each return water branch, a return water temperature sensor 53, and an outlet check valve 54. The output end of the water collection unit is connected to a river drainage outlet, forming a complete open-loop water circulation system.

[0025] In actual operation, river water, acting as the refrigerant, enters the water distribution unit through the intake. The water distribution unit then allocates the flow to two branches according to the operating conditions. The first branch is the radiant cooling branch. When the refrigerant flows through the cooling water pipe 21 of the radiant cooling unit, it exchanges sensible heat with the high-temperature air inside the tunnel through the pipe wall, absorbing heat from the air before flowing into the water collector 51 of the water collection unit. The second branch is the air conditioning dehumidification branch. The refrigerant first enters the air conditioning dehumidification unit, where it can directly exchange heat with the tunnel air to achieve pre-cooling and dehumidification. It then flows into the condenser side of the refrigeration compression unit, absorbing the condensation waste heat generated by the refrigeration cycle, and finally flows into the water collector 51 of the water collection unit. Inside the refrigeration compression unit, the refrigerant evaporates and absorbs heat in the evaporator 44, reducing the heat loss of the refrigerant flowing through the evaporator. The tunnel air temperature of the evaporator 44 is adjusted and condensation is produced. The high humidity tunnel air is cooled and dehumidified by the evaporator 44 and then sent back to the underground cable tunnel by the fan 45 configured in the refrigeration compression unit. The low temperature and low pressure refrigerant vapor after absorbing heat is compressed into high temperature and high pressure gas by the compressor 41 and enters the condenser 42 to condense into liquid by heat exchange with river water. The condensed refrigerant returns to the evaporator 44 after being throttled and depressurized by the throttling valve 43, completing the closed cycle. The water collection unit collects the return water from the two branches through the water collector 51, and the gate valve 52 of each branch realizes the single-circuit on / off control. The return water temperature sensor 53 collects the return water temperature data in real time, and finally sends it to the mixed water discharge unit in one direction through the outlet check valve 54.

[0026] In some implementations, such as Figure 1 and Figure 2 As shown, the cooling and dehumidification system also includes a water intake and treatment unit electrically connected to the control unit. The input end of the water intake and treatment unit is used to connect to the river water intake, and the output end of the water intake and treatment unit is connected to the input end of the water distribution unit.

[0027] In this embodiment, the water intake and treatment unit includes a filter screen 61, an automatic backwash filter 62, a Y-type filter 63, and an inlet control valve 64 electrically connected to the control unit. River water is collected from the river intake and first passes through the filter screen 61 to intercept large debris such as household waste and aquatic plants. The pre-purified water then flows through the inlet control valve 64 into the automatic backwash filter 62, where suspended solids, silt, algae, and other particulate impurities are retained by the filter screen. Subsequently, the water flows into the Y-type filter 63. 3. Deeply filter out tiny sand particles; the clean water after three-stage purification is delivered to the water distribution unit for subsequent branch distribution; through three-stage filtration, various impurities in river water are effectively removed, preventing silt and debris from entering subsequent pipelines and heat exchange equipment, causing blockage and wear, extending the service life of system equipment, reducing the frequency of operation and maintenance cleaning, and ensuring long-term stable operation of the system; the inlet control valve 64 is used to control the start and stop of the entire cooling and dehumidification system. During system debugging or maintenance, the start and stop status of the inlet control valve 64 can be directly controlled remotely or manually.

[0028] In some implementations, such as Figure 1 and Figure 2 As shown, it also includes a water mixing and discharge unit electrically connected to the control unit. The input end of the water mixing and discharge unit is connected to the output end of the water collection unit, and the water intake end of the water mixing and discharge unit is used to connect to the river water intake.

[0029] In this embodiment, the mixing and discharge unit is connected in series between the output end of the water collection unit and the river drainage outlet. The heated return water output by the water collection unit is first discharged into the mixing tank 75 of the mixing and discharge unit. At the same time, the mixing and discharge unit draws low-temperature raw water from the river water intake and injects it into the mixing tank 75. After being fully mixed with the heated return water and cooled to meet the discharge standards, it is then dispersed into the river through the river drainage outlet. By setting up the mixing and discharge unit, local water thermal pollution caused by direct discharge of heated return water can be avoided, the impact of system operation on the aquatic ecological environment can be reduced, and the environmental adaptability and environmental compliance of the project can be improved.

[0030] In some implementations, such as Figure 1 and Figure 2 As shown, the mixing and discharge unit includes a mixing tank 75, and a mixing pump 71, a mixing valve 72, a water intake temperature sensor 73, and a mixing temperature sensor 74 electrically connected to the control unit. The input end of the mixing tank 75 is connected to the output end of the water collection unit. The input end of the mixing valve 72 is used to connect to the river water intake. The output end of the mixing valve 72 is connected to the mixing inlet end of the mixing tank 75 through the mixing pump 71. The water intake temperature sensor 73 is located on the output side of the mixing pump 71, and the mixing temperature sensor 74 is used to obtain the water temperature in the mixing tank 75 in real time.

[0031] In this embodiment, the mixing and discharge unit adopts closed-loop temperature control logic. The control unit collects the water temperature in the mixing tank 75 in real time through the mixing temperature sensor 74, and combines it with the river raw water temperature collected by the intake temperature sensor 73 to dynamically adjust the opening and closing of the mixing valve 72 and the operating frequency of the mixing pump 71. The maximum temperature difference between intake and discharge is designed to be 5℃. When the temperature difference between the water in the mixing tank 75 and the river raw water exceeds 2℃, the control unit increases the speed of the mixing pump 71 to increase the injection volume of low-temperature raw water and accelerate the mixing and cooling of the return water and raw water. When the temperature difference is lower than 2℃, the speed of the mixing pump 71 is reduced or the mixing operation is stopped to maintain a stable water temperature. The closed-loop control method of variable frequency mixing can dynamically match the mixing flow rate according to the temperature difference between the intake and drainage. Under the premise of meeting the drainage temperature requirements of the "Surface Water Environmental Quality Standard", the energy consumption of mixing and transportation is minimized. Finally, the qualified water is discharged into the river through multiple drainage pipes in a decentralized shallow discharge manner, which accelerates the natural mixing of drainage with the surrounding water bodies, avoids the concentrated heating of drainage in local water areas, and reduces the disturbance of warm drainage to the aquatic ecological environment. The mixing tank 75 adopts an open structure, which can use the natural heat exchange between outdoor air and water to assist in cooling, further reducing the energy consumption of mixing, reducing the operating load of the mixing pump 71, and improving the energy efficiency and environmental protection of the system.

[0032] In some implementations, such as Figure 1 and Figure 2 As shown, the water distribution unit includes a water distributor 11, an inlet gate valve 12, and a water supply pump 13 and an inlet water temperature sensor 14, which are electrically connected to the control unit, respectively. The input end of the inlet gate valve 12 is used to connect to the river water intake, and the output end of the inlet gate valve 12 is connected to the input end of the water distributor 11 through the water supply pump 13. The inlet water temperature sensor 14 is located on the outlet side of the water supply pump 13. The output end of the water distributor 11 is connected to the input end of the radiant cooling unit and the input end of the air conditioning dehumidification unit, respectively.

[0033] In this embodiment, the inlet gate valve 12 is located on the inlet side of the water supply pump 13. It is used to cut off the inlet passage of the water distribution unit during system commissioning or maintenance, achieving physical isolation between the water distribution unit and the upstream pipeline, ensuring the safety of maintenance operations. Simultaneously, it can cooperate with downstream branch valves to achieve tiered water shut-off maintenance. The water supply pump 13 adopts a variable frequency operation mode, with the control unit dynamically adjusting the speed based on the real-time ambient temperature inside the underground cable tunnel and the return water temperature of each branch, thereby adjusting the total water supply flow of the system. Specifically, when the temperature inside the tunnel is high and the heat load is large, the control unit increases the speed of the water supply pump 13, increasing the total cooling water flow and enhancing the cooling effect inside the tunnel. The system achieves the following effects: When the temperature inside the tunnel is low and the heat load is small, the control unit reduces the speed of the water supply pump 13, reduces the cooling water flow, and reduces water supply energy consumption; By dynamically matching the cooling supply with the tunnel heat load, the system avoids the waste of water supply energy caused by constant flow; The inlet water temperature sensor 14 is set on the outlet side of the water supply pump 13 to collect the water supply temperature in real time and feed it back to the control unit, providing temperature parameter basis for flow regulation and operating condition judgment; The water distributor 11, as the core of water distribution, distributes the pressurized water flow to the radiant cooling branch and the air conditioning dehumidification branch, ensuring the hydraulic conditions of each branch are stable and improving the flexibility of the system's cooling and dehumidification capacity control.

[0034] In some implementations, such as Figure 1 and Figure 2 As shown, the radiant cooling unit includes multiple cooling water pipes 21 and multiple branch control valves 22 corresponding to each of the multiple cooling water pipes 21; each branch control valve 22 is electrically connected to the control unit; the input end of each cooling water pipe 21 is connected to the output end of the water distributor 11 through the corresponding branch control valve 22, and the output end of each cooling water pipe 21 is connected to the input end of the water collection unit; the cooling water pipes 21 are used for direct heat exchange with the air in the underground cable tunnel.

[0035] In this embodiment, multiple cooling water pipes 21 are laid parallel to each other longitudinally along the cable tunnel, distributed on the tunnel sidewalls and upper arc-shaped area, adapting to the arc-shaped wall structure of the tunnel. This maximizes the heat exchange area and improves overall cooling efficiency without occupying space for cable laying and personnel passage. Each cooling water pipe 21 is fitted with an inclined condensate tray 23 below it. The lower end of the condensate tray 23 connects to the drainage channel of the underground cable tunnel, used to collect condensate generated by latent heat exchange on the pipe wall and uniformly drain it, preventing condensate dripping from affecting the operation of electrical equipment inside the tunnel and ensuring tunnel operation and maintenance safety. The input end of each cooling water pipe 21 is connected to... The corresponding branch control valve 22 is connected to the output end of the water distributor 11, and the output end of each cooling water pipe 21 is uniformly connected to the input end of the water collection unit. The cooling water output by the water distributor 11 is distributed to each cooling water pipe 21 through the corresponding branch control valve 22. When the low-temperature water flows in the cooling water pipe 21, it makes large-area contact heat exchange with the air in the tunnel through the pipe wall, absorbing the sensible heat in the air and reducing the overall temperature of the tunnel. The heated water after heat exchange flows into the water collection unit from the output end of the cooling water pipe 21. All branch control valves 22 are electrically connected to the control unit and receive unified start and stop control to realize rapid adjustment of cooling capacity and respond to changes in tunnel temperature.

[0036] In some implementations, such as Figures 1 to 4 As shown, the air conditioning dehumidification unit includes a chilled water coil 31, a bypass pipe 32, and a first three-way valve 33 and a second three-way valve 34 electrically connected to the control unit. The inlet of the first three-way valve 33 is connected to the output of the water distributor 11, and the two outlets of the first three-way valve 33 are respectively connected to the input of the chilled water coil 31 and the input of the bypass pipe 32. The two inlets of the second three-way valve 34 are respectively connected to the output of the bypass pipe 32 and the output of the chilled water coil 31, and the output of the second three-way valve 34 is connected to the condensate inlet of the refrigeration compressor unit.

[0037] In this embodiment, the first three-way valve 33 is an electrically adjustable three-way valve, located at the water inlet branch point after the water supply branch pipe connects to the air conditioning equipment 35. Its inlet end is connected to the water supply branch pipe, and its two outlet ends are respectively connected to the water inlet of the chilled water coil 31 and the water inlet of the bypass pipe 32. It is used to dynamically adjust the water volume distribution entering the chilled water coil 31 and the bypass pipe 32 according to the river water temperature, thereby switching the dehumidification operation mode. The second three-way valve 34 is a confluence three-way fitting, located at the water outlet junction point of the chilled water coil 31 and the bypass pipe 32. Its two inlet ends are respectively connected to the water outlet of the chilled water coil 31 and the water outlet of the bypass pipe 32, and its outlet end is connected to the cooling water inlet of the condenser 42 of the refrigeration compression unit. It is used to combine the two water flows and send them to the condenser 42 to remove the condensation heat generated by the refrigeration cycle. The cooling water from the distributor 11 enters the first three-way valve 33 through the water supply straight pipe and is divided into two paths. One path enters the chilled water coil 31 to exchange heat with the air in the tunnel, achieving air cooling and dehumidification. The other path flows directly to the second three-way valve 34 through the bypass pipe 32. The two water flows converge at the second three-way valve 34 and enter the condenser 42 of the refrigeration compression unit. After absorbing the condensation heat, it flows out to the return water branch pipe connected to the water collector 51. The control unit adjusts the opening of the first three-way valve 33 according to the real-time water temperature of the river water, which can realize three operating modes of chilled water coil 31: full-pass, full-bypass, and partial-bypass. This allows for flexible switching of the utilization mode of chilled water coil 31. When the river water temperature is suitable, the natural cold source can be fully utilized for dehumidification. When the river water temperature is high, the bypass chilled water coil 31 is used only for condensation cooling, achieving efficient cascade utilization of the cold source.

[0038] like Figure 5 As shown, the present invention also provides a cooling and dehumidification method for underground cable tunnels, the cooling and dehumidification method being implemented based on the cooling and dehumidification system described in any of the preceding claims, the cooling and dehumidification method comprising: 101. Obtain a pre-built maintenance plan, which includes one or more maintenance tasks; 102. When the time difference between the trigger time of any maintenance task and the current time is less than or equal to the preset preparation time threshold, the cooling and dehumidification system is controlled to sequentially execute the personnel maintenance mode and the heat exhaust and dehumidification mode. 103. When the time difference between the trigger time of all maintenance tasks and the current time is greater than the preset preparation time threshold, control the cooling and dehumidification system to alternately execute the heat exhaust and dehumidification mode and the ventilation mode. 104. In the event of an abnormal accident, the cooling and dehumidification system shall be controlled to sequentially execute the ventilation mode, personnel maintenance mode, and heat exhaust and dehumidification mode.

[0039] Traditional cable tunnel environmental control systems mostly adopt a fixed operation mode, which cannot match the differentiated needs of different scenarios such as unmanned daily operation, personnel maintenance, and post-accident recovery. If they are operated according to maintenance standards for a long time, it will lead to energy waste. If they are operated according to unmanned standards for a long time, they cannot meet the safety requirements for personnel to enter the site. Moreover, the lack of standardized recovery procedures after an accident can easily lead to safety risks.

[0040] This invention provides a cooling and dehumidification method. By predicting maintenance needs through maintenance plans and initiating personnel maintenance mode in advance with a 1-hour preparation time threshold, pre-ventilation and pre-cooling can be completed simultaneously, ensuring that the temperature, humidity, and air quality of the underground cable tunnel meet standards before personnel enter. This eliminates the need for manual scheduling, significantly improving operation and maintenance efficiency and operational safety. During periods without maintenance tasks, an alternating operation mode of heat exhaust and dehumidification with ventilation is adopted. This not only continuously ensures the safety of temperature and humidity for tunnel equipment operation but also maintains air quality through timed ventilation, avoiding redundant energy consumption caused by continuous ventilation. Furthermore, the personnel maintenance process already includes a complete ventilation procedure, eliminating the need to repeat daily ventilation within the corresponding cycle, further avoiding ineffective energy consumption. Through timing control logic, precise matching between the system operation mode and the actual operating state of the tunnel is achieved. Compared with a constant operation strategy, this method minimizes the running time of high-energy-consuming modes while ensuring environmental safety in all scenarios. It achieves energy-saving optimization of the system from an overall timing perspective, while also improving the automation level and emergency response capability of tunnel operation and maintenance.

[0041] In this embodiment, when an abnormal accident occurs, the ventilation mode is first executed, operating at a rate of no less than 6 air changes per hour to quickly remove harmful gases such as fire smoke and fire extinguishing exhaust from the tunnel until the air quality meets the standards for personnel entry; then, the system switches to the personnel inspection mode to provide a safe environment for personnel to enter and inspect; finally, the heat exhaust and dehumidification mode is restored to bring the tunnel back to normal operation.

[0042] In some embodiments, controlling the cooling and dehumidification system to sequentially execute a personnel maintenance mode and a heat exhaust and dehumidification mode includes: 201. Obtain real-time ambient temperature and relative humidity inside underground cable tunnels, as well as real-time water temperature of rivers; In this embodiment, under the heat exhaust and dehumidification mode, the temperature control of the radiant cooling unit is set with 38℃ as the start threshold and 35℃ as the stop threshold, with the 35℃-38℃ range being the temperature dead zone. When the real-time ambient temperature is ≥38℃, the radiant cooling unit is turned on, and the cooling water pipe 21 is activated. When the real-time ambient temperature is <35℃, the radiant cooling unit is turned off to stop radiant cooling. When the ambient temperature is in the temperature dead zone of 35℃-38℃, the radiant cooling unit maintains its original operating state. The 38℃ start threshold is set based on the 40℃ safety threshold for tunnel equipment operation, with a 2℃ safety margin. 35℃ is the lower limit for stopping cooling, corresponding to the temperature range for safe equipment operation, avoiding frequent start-stop cycles. The heat exhaust and dehumidification mode corresponds to unmanned operation. Under unmanned operation, the temperature requirements can be appropriately relaxed to further reduce the operating time of the cooling equipment and reduce daily operating energy consumption.

[0043] 202. Control the cooling and dehumidification system to first execute the personnel maintenance mode. Based on the real-time ambient temperature and the comparison results between the real-time ambient temperature and the real-time water temperature, adjust the start-stop status of the radiant cooling unit and the air conditioning dehumidification unit. At the same time, based on the real-time relative humidity, adjust the start-stop status of the air conditioning dehumidification unit so that the real-time ambient temperature and real-time relative humidity meet the preset maintenance environment temperature and humidity requirements. In this embodiment, under personnel maintenance mode, the temperature control of the radiant cooling unit uses 33℃ as the start threshold and 28℃ as the stop threshold, with the 28℃-33℃ range being the temperature dead zone. When the real-time ambient temperature is ≥33℃, the real-time water temperature Tf is further compared with the real-time ambient temperature Tin, with a 1℃ water temperature margin introduced for judgment, i.e., verifying whether (Tf-1) < Tin is true. If true, i.e., (Tf-1) < Tin, it indicates that the river water temperature has sufficient cooling temperature difference, and the radiant cooling unit is controlled to enter the open state, and the cooling water pipe 21 is put into operation. If the condition is not true, (Tf-1) ≥ Tin, it indicates that the river water temperature is close to or higher than the real-time ambient temperature, and the cooling efficiency is low, so the radiant cooling unit is shut down, and the air conditioning dehumidification unit is started to cooperate with the refrigeration compression unit for mechanical refrigeration cooling. When the real-time ambient temperature is ≥33℃, the radiant cooling unit is controlled to enter the open state, and the cooling water pipe 21 is put into operation. When the temperature is below 28℃, the radiant cooling unit is shut down to stop radiant cooling. When the ambient temperature is in the temperature dead zone of 28℃-33℃, the radiant cooling unit maintains its original operating state. If it is already in operation, the 1℃ water temperature margin condition is rechecked. If the condition is not met, the air conditioning dehumidification unit is switched on to cooperate with the refrigeration compression unit for mechanical cooling. The 33℃ start-up threshold is set based on the safety standard that the tunnel temperature should not exceed 35℃ during personnel maintenance, with a 2℃ safety margin reserved to avoid excessive temperature fluctuations. The 28℃ stop-down threshold is the lower limit of the hysteresis range to prevent frequent start-stop of the fan, and it is also the lower limit of the temperature for pursuing a comfortable working environment. No additional cooling is required below this temperature. The 1℃ water temperature margin can prevent the cooling water pipe 21 from having low heat exchange efficiency and frequent start-stop when the water temperature is close to the ambient temperature, thus improving the stability of system operation.

[0044] Secondly, in personnel maintenance mode, the humidity control of the air conditioning dehumidification unit is set with a starting threshold of 70% and a stopping threshold of 60%, with the 60%-70% range being a humidity dead zone. When the real-time relative humidity is ≥70%, the control unit turns on the air conditioning dehumidification unit to dehumidify; when the real-time relative humidity is <60%, the air conditioning dehumidification unit turns off to stop dehumidification; when the real-time relative humidity is in the humidity dead zone, the original operating state is maintained. The upper limit of 70% humidity is set based on the characteristic that high humidity environments accelerate the corrosion and aging of electrical equipment, and exceeding this threshold will significantly shorten the equipment lifespan; the lower limit of 60% humidity takes into account both dehumidification energy consumption and equipment protection needs, avoiding excessive dehumidification that would lead to energy waste; the dead zone setting can reduce frequent start-stop of the equipment and extend its service life.

[0045] Secondly, the personnel maintenance mode is equipped with a complete ventilation control process. One hour before the maintenance begins, the pre-maintenance ventilation condition is implemented. The fresh air fan in the underground cable tunnel supplies fresh air at a standard of 30m³ / h per person to meet the hygiene needs of the workers. The ventilation fan 8 is used to enhance air flow, eliminate ventilation dead corners, and serve as a relay device in long-distance ventilation sections to prevent heat or polluted air from accumulating in one place.

[0046] 203. When the maintenance task is completed, control the cooling and dehumidification system to execute the heat exhaust and dehumidification mode, adjust the start and stop status of the radiant cooling unit and the air conditioning dehumidification unit based on the real-time ambient temperature, and adjust the start and stop status of the air conditioning dehumidification unit based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset heat exhaust and dehumidification working conditions. 204. When the personnel maintenance mode or heat exhaust and dehumidification mode is executed, if the air conditioning dehumidification unit is in the on state, the working state of the air conditioning dehumidification unit is adjusted based on the real-time water temperature. In this embodiment, when the air conditioning dehumidification unit is turned on, the system adjusts the operating mode according to the real-time water temperature. When the real-time water temperature is ≥28℃, the first three-way valve 33 is closed to close the chilled water coil 31 passage and fully open the bypass pipe 32, allowing all river water to bypass to the condenser 42. The cooling function of the chilled water coil 31 is disabled, and the refrigeration compression unit is activated for mechanical dehumidification. The second three-way valve 34 then directs all bypass water flow into the condenser 42. When the real-time water temperature is <19℃, the first three-way valve 33 is fully opened to open the chilled water coil 31 passage and close the bypass pipe 32, allowing all river water to flow through the chilled water coil 31 for dehumidification. The refrigeration compression unit is disabled, and the second three-way valve 34 directs all water from the chilled water coil 31 into the condenser 42. When the water temperature is between 19℃ and 28℃, the first three-way valve 33 is fully opened. The system opens the passage for the chilled water coil 31, allowing all river water to enter the chilled water coil 31 for pre-cooling. Simultaneously, the refrigeration compression unit is activated to supplement the moisture load. The second three-way valve 34 directs all water from the chilled water coil 31 into the condenser 42. The 28℃ water temperature threshold corresponds to an air dew point temperature of 28.69℃ under tunnel conditions of 35℃ and 70% relative humidity. When the real-time water temperature exceeds this value, the chilled water coil 31 cannot effectively dehumidify. The 19℃ water temperature threshold corresponds to an air dew point temperature of 19.53℃ under conditions of 28℃ and 60% relative humidity (atmospheric pressure is assumed to be 101.325 kPa). When the real-time water temperature is below this value, the chilled water coil 31 can independently meet dehumidification requirements. Through this tiered mode, the dehumidification capacity of the natural cold source can be maximized, reducing the operating time of mechanical refrigeration and significantly lowering dehumidification energy consumption.

[0047] In this embodiment, a hierarchical control logic is adopted when a maintenance task is required, which has the following advantages: In terms of safety, the personnel maintenance mode and the heat dissipation and dehumidification mode adopt differentiated temperature thresholds, matching the 35℃ safety upper limit for personnel operation and the 40℃ safety upper limit for equipment operation, respectively. This ensures the occupational health and safety of maintenance personnel and avoids the waste of cooling capacity caused by excessive cooling in unmanned conditions. The supporting graded ventilation process follows the operation safety specifications, forming an effective safety guarantee from pre-ventilation to fresh air supply during operation, which can avoid the safety risk of harmful gas accumulation. In terms of energy efficiency optimization, the control principle of prioritizing natural cold sources is followed. Effective cooling conditions are screened by a 1℃ water temperature margin, maximizing the use of free river cold sources to bear sensible and latent heat loads. Mechanical refrigeration is only used when the capacity of natural cold sources is insufficient, which can significantly reduce the operating time of high-energy-consuming equipment and greatly reduce the system's annual operating energy consumption. At the same time, the three-level zoned air conditioning and dehumidification control of water temperature realizes the tiered utilization of cold sources and avoids the ineffective investment of mechanical refrigeration.

[0048] In some embodiments, controlling the cooling and dehumidification system to alternately execute a heat exhaust and dehumidification mode and a ventilation mode includes: 301. Obtain the real-time ambient temperature and relative humidity inside the underground cable tunnel, as well as the real-time water temperature of rivers; 302. Control the cooling and dehumidification system to first execute the heat exhaust and dehumidification mode, adjust the start and stop status of the radiant cooling unit and the air conditioning dehumidification unit based on the real-time ambient temperature, and adjust the start and stop status of the air conditioning dehumidification unit based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset heat exhaust and dehumidification working conditions. 303. When the air conditioning dehumidification unit is in the on state, adjust the working state of the air conditioning dehumidification unit based on the real-time water temperature; 304. When the preset air exchange time point is reached, control the cooling and dehumidification system to execute the ventilation mode according to the preset number of air exchanges; In this embodiment, the preset ventilation time can be set to 0:00 AM daily, or it can be set to automatically trigger the ventilation mode corresponding to the daily ventilation conditions when the system has not been ventilated for 24 consecutive hours. Specifically, the daily ventilation condition adopts a combination of natural air intake and mechanical exhaust. Fresh air can be actively introduced through the fresh air fan equipped in the underground cable tunnel, or fresh air can be introduced by creating negative pressure by turning on the exhaust fan equipped in the underground cable tunnel. At the same time, the ventilation fan 8 installed in the underground cable tunnel can enhance local airflow circulation and improve ventilation effect. Under the daily ventilation condition, the air exchange rate is 1 time / hour, and the single operation time is 1 hour. After the operation ends, the heat exhaust and dehumidification mode is automatically restored. The reason for choosing the early morning time for ventilation is that the outdoor temperature is the lowest at this time, the heat brought in by the introduced fresh air is the least, and the impact on the temperature environment inside the tunnel is the least. This can avoid the tunnel temperature rising due to ventilation and reduce subsequent cooling energy consumption.

[0049] In this embodiment, an alternating operation mode is adopted, which can achieve a dual balance between stable thermal and humid environment and air quality assurance in unattended daily scenarios, combining energy saving and reliability. With heat exhaust and dehumidification mode as the main normal operation mode, the temperature and humidity of the tunnel are continuously regulated by natural cold source of river water. Compared with the high-energy-consuming mode of traditional ventilation and cooling that relies on continuous operation of large air volume, this alternating operation mode can significantly reduce the energy consumption of fans and cooling loss in daily operation. In addition, the daily ventilation mode triggered at timed intervals adopts a low-frequency and short-duration operation strategy, which only meets the basic air quality requirements, avoids excessive ventilation that leads to a large intrusion of hot and humid outdoor air, and reduces the additional cooling and dehumidification load caused by this.

[0050] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A cooling and dehumidification system for underground cable tunnels, characterized in that, The system includes a control unit, and a water distribution unit, a radiant cooling unit, an air conditioning dehumidification unit, a refrigeration compression unit, and a water collection unit, all electrically connected to the control unit. The input end of the water distribution unit is connected to a river water intake. The output end of the water distribution unit is connected to the input ends of the radiant cooling unit and the air conditioning dehumidification unit, respectively. The output end of the air conditioning dehumidification unit is connected to the condensate inlet of the refrigeration compression unit. The output ends of the radiant cooling unit and the condensate outlet of the refrigeration compression unit are connected to the input end of the water collection unit, respectively. The output end of the water collection unit is connected to a river drainage outlet.

2. The cooling and dehumidification system according to claim 1, characterized in that, It also includes a water intake and treatment unit electrically connected to the control unit. The input end of the water intake and treatment unit is used to connect to the river water intake, and the output end of the water intake and treatment unit is connected to the input end of the water distribution unit.

3. The cooling and dehumidification system according to claim 1, characterized in that, It also includes a water mixing and discharge unit electrically connected to the control unit. The input end of the water mixing and discharge unit is connected to the output end of the water collection unit, and the water intake end of the water mixing and discharge unit is used to connect to the river water intake.

4. The cooling and dehumidification system according to claim 3, characterized in that, The mixing and discharge unit includes a mixing tank, a mixing pump, a mixing valve, a water intake temperature sensor, and a mixing temperature sensor electrically connected to the control unit. The input end of the mixing tank is connected to the output end of the water collection unit. The input end of the mixing valve is used to connect to the river water intake. The output end of the mixing valve is connected to the mixing inlet of the mixing tank through the mixing pump. The water intake temperature sensor is located on the output side of the mixing pump and is used to acquire the water temperature in the mixing tank in real time.

5. The cooling and dehumidification system according to claim 1, characterized in that, The water distribution unit includes a water distributor, an inlet gate valve, and a water supply pump and an inlet water temperature sensor, which are electrically connected to the control unit. The input end of the inlet gate valve is used to connect to the river water intake, and the output end of the inlet gate valve is connected to the input end of the water distributor through the water supply pump. The inlet water temperature sensor is located on the outlet side of the water supply pump. The output end of the water distributor is connected to the input end of the radiant cooling unit and the input end of the air conditioning dehumidification unit.

6. The cooling and dehumidification system according to claim 5, characterized in that, The radiant cooling unit includes multiple cooling water pipes and multiple branch control valves corresponding to each of the multiple cooling water pipes; each branch control valve is electrically connected to the control unit; the input end of each cooling water pipe is connected to the output end of the water distributor through the corresponding branch control valve, and the output end of each cooling water pipe is connected to the input end of the water collection unit; the cooling water pipes are used for direct heat exchange with the air in the underground cable tunnel.

7. The cooling and dehumidification system according to claim 5, characterized in that, The air conditioning dehumidification unit includes a chilled water coil, a bypass pipe, and a first three-way valve and a second three-way valve electrically connected to the control unit. The inlet of the first three-way valve is connected to the output of the water distributor, the two outlets of the first three-way valve are respectively connected to the input of the chilled water coil and the input of the bypass pipe, the two inlets of the second three-way valve are respectively connected to the output of the bypass pipe and the output of the chilled water coil, and the output of the second three-way valve is connected to the condensate inlet of the refrigeration compressor unit.

8. A cooling and dehumidification method for underground cable tunnels, characterized in that, The cooling and dehumidification method is implemented based on the cooling and dehumidification system as described in any one of claims 1-7, and the cooling and dehumidification method includes: Obtain a pre-built maintenance plan, which includes one or more maintenance tasks; When the time difference between the trigger time of any maintenance task and the current time is less than or equal to the preset preparation time threshold, the cooling and dehumidification system is controlled to sequentially execute the personnel maintenance mode and the heat exhaust and dehumidification mode. When the time difference between the trigger time of all maintenance tasks and the current time is greater than the preset preparation time threshold, the cooling and dehumidification system is controlled to alternately execute the heat exhaust and dehumidification mode and the ventilation mode. In the event of an abnormal accident, the cooling and dehumidification system is controlled to sequentially execute the ventilation mode, personnel maintenance mode, and heat exhaust and dehumidification mode.

9. The cooling and dehumidification method according to claim 8, characterized in that, The control of the cooling and dehumidification system to sequentially execute personnel maintenance mode and heat exhaust and dehumidification mode includes: It can obtain real-time ambient temperature and relative humidity inside underground cable tunnels, as well as real-time water temperature of rivers. The cooling and dehumidification system is first controlled to execute the personnel maintenance mode. Based on the real-time ambient temperature and the comparison between the real-time ambient temperature and the real-time water temperature, the start-stop status of the radiant cooling unit and the air conditioning dehumidification unit is adjusted. At the same time, based on the real-time relative humidity, the start-stop status of the air conditioning dehumidification unit is adjusted so that the real-time ambient temperature and real-time relative humidity meet the preset maintenance environment temperature and humidity requirements. When the maintenance task is completed, the cooling and dehumidification system is controlled to execute the heat exhaust and dehumidification mode. The start and stop status of the radiant cooling unit and the air conditioning dehumidification unit are adjusted based on the real-time ambient temperature, and the start and stop status of the air conditioning dehumidification unit is adjusted based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset heat exhaust and dehumidification conditions. When the system is in maintenance mode or heat exhaust and dehumidification mode, if the air conditioning dehumidification unit is on, the operating status of the air conditioning dehumidification unit will be adjusted based on the real-time water temperature.

10. The cooling and dehumidification method according to claim 8, characterized in that, The control of the cooling and dehumidification system to alternately execute the heat exhaust and dehumidification mode and the ventilation mode includes: The system obtains real-time ambient temperature and relative humidity inside underground cable tunnels, as well as real-time water temperature of rivers. The cooling and dehumidification system is controlled to first execute the heat exhaust and dehumidification mode, and the start and stop status of the radiant cooling unit and the air conditioning dehumidification unit is adjusted based on the real-time ambient temperature, and the start and stop status of the air conditioning dehumidification unit is adjusted based on the real-time relative humidity, so that the real-time ambient temperature and real-time relative humidity meet the preset heat exhaust and dehumidification conditions. When the air conditioning dehumidification unit is turned on, the working status of the air conditioning dehumidification unit is adjusted based on the real-time water temperature. When the preset air exchange time is reached, the cooling and dehumidification system is controlled to execute the ventilation mode according to the preset number of air exchanges.

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