Deep energy recovery system and method based on multistage serial preheating

Abstract

The invention discloses a deep energy recovery system and method based on multistage serial preheating. The system comprises an intermittent heating unit, a heat transmission network, a sensor group and a controller. After the system enters a steady state cycle, when a target unit needs to be heated from a preset low temperature to a target high temperature, a controller intelligently dispatches a heat transmission network, so that the target unit sequentially and serially receives waste heat provided by other source units in the system, and multi-stage preheating is performed; and the initial temperature of the main heating stage is furthest improved. Under the ideal condition, the steady-state main heating energy consumption of the method approaches to 1 / 2 (N-1) of the basic energy consumption E0, so that the energy consumption can be greatly reduced. The method is particularly suitable for drying ovens or press clusters in the fields of PCB manufacturing, composite material forming and the like, and has huge economic and environment-friendly values.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board (PCB) manufacturing, and particularly to a deep energy recovery system and method based on multi-stage serial preheating. BACKGROUND

[0002] In many industrial fields such as electronic manufacturing (especially printed circuit board (PCB) manufacturing), composite material forming, food processing, pharmaceuticals, etc., batch heating equipment such as ovens, presses, autoclaves, etc. are widely used. The common working mode of these devices is to heat the material to be processed from the ambient temperature or a certain lower initial temperature (T1) to a higher target temperature (T2) required by the process, and maintain it for a period of time. This heating process is often the main energy consumption link. After the heating and holding cycle is completed, a large amount of heat energy carried by the device itself and its internal material is directly dissipated into the surrounding environment during the subsequent cooling process, not only causing huge energy waste and increasing production costs, but also possibly causing heat pollution to the workshop environment.

[0003] In order to reduce the energy consumption of such equipment, some measures have been taken in the prior art. For example, by improving the furnace structure, using high-efficiency insulation materials, and strengthening the sealing, etc. to reduce the heat loss of the equipment itself. For combustion heating equipment, sometimes the flue gas waste heat is used to preheat the combustion air. In some systems, attempts have also been made to use the heat of the hot air or cooling medium discharged by the equipment to preheat the fresh air or cooling medium entering (exhaust gas / liquid heat recovery). However, the existing energy-saving technologies and heat recovery methods generally have the following limitations: Limited heat recovery efficiency: Especially for a cluster of batch equipment mainly using electric heating, simple exhaust gas heat recovery application scenarios are limited or ineffective. The proportion of heat recovered by single preheating between devices is limited, and the overall energy-saving potential inherent in the system cannot be fully tapped.

[0004] Lack of deep utilization mechanism: The existing technology is a simple energy recovery strategy. When a device needs to be cooled, part of its waste heat is introduced into another device that is preparing to be heated, for one-time and simple preheating.

[0005] Therefore, it is urgent to develop an innovative and systematic deep energy recovery technology that can more effectively utilize the large amount of waste heat generated during the operation of a cluster of batch heating equipment to significantly reduce overall energy consumption. SUMMARY

[0006] The purpose of the present application is to improve and innovate in view of the shortcomings and problems in the background art, and to provide a deep energy recovery system and method based on multi-stage serial preheating.

[0007] According to a first aspect of the present application, a multi-stage serial preheating based deep energy recovery system is provided, comprising: N intermittent heating units; a heat transfer network configured to establish independent heat transfer paths among the N intermittent heating units; a sensor group for monitoring the operating states of the intermittent heating units and the heat transfer network; and a controller for monitoring the operating states of the N intermittent heating units in real time, identifying one or more intermittent heating units currently available as heat sources as source units when a target unit needs to start a heating cycle from a preset low temperature, controlling the heat transfer network to enable the target unit to sequentially and serially receive heat input from the identified at least one, at most N-1 source units, complete a multi-stage preheating process, and reach a preheating endpoint temperature, and after completing the multi-stage preheating process, start the main heating system of the target unit to heat it from the preheating endpoint temperature to the target high temperature, so that the energy consumption of the main heating system of the target unit approaches 1 / 2^(N-1) of the basic energy consumption E0, where the basic energy consumption E0 is the energy consumption corresponding to the direct heating of the target unit from the preset low temperature to the target high temperature by the main heating system.

[0008] Further, the intermittent heating unit is an oven or a heat press.

[0009] Further, when the intermittent heating unit is an oven, the heat transfer network comprises a first main pipe, a second main pipe, an actuator, and a third main pipe, the second main pipe is connected to the input end of the actuator, the third main pipe is connected to the output end of the actuator, the actuator is a fan; the first main pipe, the second main pipe, and the third main pipe are respectively provided with first branch pipes, second branch pipes, and third branch pipes corresponding to the intermittent heating units one by one, the first branch pipes, the second branch pipes, and the third branch pipes are all provided with valves, and the first branch pipes and the third branch pipes are arranged on both sides of the intermittent heating units.

[0010] Further, the first branch pipes and the second branch pipes are both provided with three-way pipes, and the three-way pipes corresponding to the first branch pipes and the second branch pipes are fixedly connected together through a connecting pipe, and the connecting pipe is also provided with a valve; the third branch pipes are also provided with a three-way pipe, and the end of the first branch pipe away from the first main pipe is connected to the three-way pipe.

[0011] A further embodiment is that, when the intermittent heating unit is a hot press, the heat transfer network includes a first main pipe, a second main pipe, an actuator, and a third main pipe. The second main pipe is connected to the input end of the actuator, and the third main pipe is connected to the output end of the actuator. The actuator is a heat transfer oil pump. The first, second, and third main pipes are respectively provided with a first branch pipe, a second branch pipe, and a third branch pipe corresponding to the intermittent heating unit. Valves are provided on the first, second, and third branch pipes, and the first and third branch pipes are located on opposite sides of the intermittent heating unit. T-junctions are provided on the first and second branch pipes, and the corresponding t-junctions of the first and second branch pipes are fixedly connected together by a connecting pipe, which is also provided with a valve.

[0012] A further option is to also install a tee pipe on the third branch pipe, with the end of the first branch pipe furthest from the first main pipe connected to the tee pipe.

[0013] According to a second aspect of the present invention, a deep energy recovery method based on multi-stage serial preheating is provided, comprising the following steps: Step S101: When an intermittent heating unit needs to start its heating cycle, it is designated as the target unit. One or more intermittent heating units that can currently serve as heat sources are identified and designated as source units. A serial execution sequence is planned to preheat the target unit using the identified intermittent heating units. Step S102: The heat transfer network is controlled to execute each preheating sub-process. In each preheating sub-process, a heat transfer path is established from the intermittent heating unit in the current serial execution sequence to the target unit, and heat transfer is performed until the preset termination condition for that preheating stage is met. Step S103: Repeat step S102 until all planned intermittent heating units in the sequence have preheated the target unit, so that the target unit reaches the preheating endpoint temperature; Step S104: Start the main heating system of the target unit and heat it from the preheating endpoint temperature to the target high temperature, so that the energy consumption of the main heating system of the target unit is close to 1 / 2^(N-1) of the basic energy consumption E0, where the basic energy consumption E0 is the energy consumption corresponding to the main heating system directly heating the target unit from the preset low temperature to the target high temperature, and N is the number of intermittent heating units.

[0014] A further embodiment is that step S102 specifically includes: Precisely control the relevant valves in the heat transfer network, open the heat transfer channel from the source unit to the target unit in the current sequence, and start or adjust the relevant heat transfer oil circulation pumps or fans; Monitor the temperature rise rate and real-time temperature of the target unit, as well as the temperature fall rate of the source unit; dynamically adjust the valve opening or the speed of the heat transfer oil circulation pump and fan to control the heat transfer rate; Determine whether the preheating between the source unit and the target unit in the current sequence has reached the preheating termination condition; If so, shut down the heat transfer channel from the source unit to the target unit in the current sequence, and shut down the corresponding heat transfer oil circulation pump or fan.

[0015] A further option is that the temperature of the target unit reaches the preset intermediate target value for that level of preheating, or the temperature difference between the target unit and the current source unit is less than a preset threshold, or the maximum allowable preheating duration for that level is reached, or the temperature of the current source unit is lower than the minimum allowable temperature for it to be an effective heat source.

[0016] A further approach is that, after step S104, the state of the target unit that has completed heating is updated to that of a potential source unit, enabling it to participate in the preheating of other intermittent heating units during subsequent cooling processes, thereby maintaining the steady-state energy cycle of the system. Compared with the prior art, the beneficial effects of the present invention are: (1) revolutionary energy saving potential: by implementing a unique multi-stage serial preheating strategy, under ideal conditions, the main heating energy consumption of a single unit in the steady-state cycle can theoretically be reduced to E0 / 2^(N-1) (E0 is the basic energy consumption without preheating), and the energy saving efficiency increases exponentially with the number N of intermittent heating units, far exceeding any existing heat recovery technology.

[0017] (2) Significantly reduce operating costs: Reduce electricity or fuel consumption significantly, directly reduce production costs, and improve the company's economic benefits and market competitiveness.

[0018] (3) Promote green and sustainable manufacturing: By maximizing the internal recycling of energy, energy waste and corresponding carbon emissions are greatly reduced (for electric heating, emissions from the power generation side are reduced), which helps enterprises meet increasingly stringent environmental regulations and establish a green and low-carbon social image.

[0019] (4) The entire energy recovery process is automatically completed by the intelligent controller based on real-time data, without the need for manual intervention, and is easy to integrate into a modern intelligent factory management system.

[0020] (5) The principles and methods of this invention are applicable to various industrial scenarios that require the use of multiple identical or similar intermittent heating devices, especially for industries such as PCB manufacturing, composite materials, and automotive parts that have oven clusters and press units, which have great application value and transformation potential. Attached Figure Description

[0021] Figure 1This is a schematic diagram of a deep energy recovery system based on multi-stage serial preheating, provided as an embodiment of the present invention.

[0022] Reference numerals: 1. Intermittent heating unit; 201. First main pipe; 202. Second main pipe; 203. Actuator; 204. Third main pipe; 205. First branch pipe; 206. Second branch pipe; 207. Third branch pipe; 208. Connecting pipe. Detailed Implementation

[0023] To make the objectives, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] Example 1 Please see Figure 1 This invention provides a deep energy recovery system based on multi-stage serial preheating. The system includes N intermittent heating units 1 and a heat transfer network. In this embodiment, the intermittent heating unit 1 is an oven. The heat transfer network includes a first main pipe 201, a second main pipe 202, an actuator 203, and a third main pipe 204. The second main pipe 202 is connected to the input end of the actuator 203, and the third main pipe 204 is connected to the output end of the actuator 203. The actuator 203 is a fan. The first main pipe 201, the second main pipe 202, and the third main pipe 204 are respectively provided with a first branch pipe 205, a second branch pipe 206, and a third branch pipe 207 corresponding to the intermittent heating units. Valves are provided on the first branch pipe 205, the second branch pipe 206, and the third branch pipe 207, and the first branch pipe 205 and the third branch pipe 207 are located on both sides of the intermittent heating unit.

[0026] Preferably, both the first branch pipe 205 and the second branch pipe 206 are equipped with tee pipes, and the corresponding tee pipes of the first branch pipe 205 and the second branch pipe 206 are fixedly connected together by a connecting pipe 208, which is also equipped with a valve; the third branch pipe 207 is also equipped with a tee pipe, and the end of the first branch pipe 205 away from the first main pipe 201 is connected to this tee pipe. It can be understood that when the two intermittent heating units 1 exchange heat, by controlling the opening and closing of the valves, the airflow direction in each intermittent heating unit 1 can be made to flow from top to bottom, which is conducive to the full discharge of hot air and greatly improves the heat exchange efficiency between the intermittent heating units 1.

[0027] It should be noted that the system also includes a controller, a temperature sensor, and a main heating system. The temperature sensor monitors the temperature inside the oven, and the main heating system heats the air inside the oven; the main heating system can be an electric heating element. The controller connects the temperature sensor, valves, and the main heating system to achieve intelligent scheduling of the entire system.

[0028] In this embodiment, the number of ovens can be set to 4; the ovens are 1a, 1b, 1c and 1d respectively. It should be understood that setting the number of ovens to 4 is just an example, and the specific number of ovens can be set according to the requirements.

[0029] For example, when ovens 1a, 1b, and 1c have just finished baking a batch of products and are waiting for or starting to cool down, oven 1d is loaded with a new batch of products to be baked. Since ovens 1a, 1b, and 1c have just finished baking a batch of products, the air temperature inside their ovens is relatively high; while oven 1d has just been loaded with products to be baked, the air temperature inside its oven is relatively low. Therefore, ovens 1a, 1b, and 1c can be used sequentially to preheat oven 1d, thereby realizing the recovery and utilization of the heat energy of ovens 1a, 1b, and 1c. This can reduce the energy consumption of oven 1d during the main heating stage and improve the energy utilization efficiency of the entire equipment cluster.

[0030] For example, consider the use of an oven for dehumidifying and baking PP materials before lamination in PCB production. The process requires heating the PP material from room temperature T1=25°C to a target temperature T2=105°C and holding it at that temperature for a period of time. The PP material to be baked is placed in oven 1d. Ovens 1a, 1b, and 1c have just finished baking a batch of products. To recover and utilize the heat energy from the ovens, the controller first opens the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to oven 1c, and the valves on the third branch pipe 207 and the connecting pipe 208 corresponding to oven 1d. It also turns on the fan, causing the air in ovens 1c and 1d to flow from top to bottom, quickly and evenly mixing the air in ovens 1c and 1d, thereby raising the temperature in oven 1d to T_int_1. Then, control the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to oven 1b, and the valves on the third branch pipe 207 and the connecting pipe 208 corresponding to oven 1d to open, so that oven 1d can exchange heat with the air in oven 1b, and the temperature in oven 1d can rise to T_int_2; finally, use the same method to achieve heat exchange between oven 1d and the air in oven 1a, so that the temperature in oven 1d can reach the final preheating endpoint T_start, and the main heating system in oven 1d only needs to be responsible for the temperature rise from T_start to T2.

[0031] Example 2 Please continue reading. Figure 1 The present invention provides a deep energy recovery system based on multi-stage serial preheating. The system includes N intermittent heating units 1 and a heat transfer network. The intermittent heating unit 1 is a hot press. The heat transfer network includes a first main pipe 201, a second main pipe 202, an actuator 203, and a third main pipe 204. The second main pipe 202 is connected to the input end of the actuator 203, and the third main pipe 204 is connected to the output end of the actuator 203. The actuator 203 is a heat transfer oil pump. The first main pipe 201, the second main pipe 202, and the third main pipe 204 are respectively provided with a first branch pipe 205, a second branch pipe 206, and a third branch pipe 207 corresponding to the intermittent heating unit. Valves are provided on the first branch pipe 205, the second branch pipe 206, and the third branch pipe 207 are located on both sides of the intermittent heating unit. A tee pipe is provided on the first branch pipe 205 and the second branch pipe 206, and the tee pipes corresponding to the first branch pipe 205 and the second branch pipe 206 are fixedly connected together by a connecting pipe 208, which is also provided with a valve.

[0032] Preferably, a tee pipe is also provided on the third branch pipe 207, and the end of the first branch pipe 205 away from the first main pipe 201 is connected to the tee pipe.

[0033] It should be noted that the system also includes a controller, a temperature sensor, and a main heating system. The temperature sensor is used to monitor the temperature of the heat transfer oil inside the hot press, the main heating system is used to heat the heat transfer oil inside the hot press, and the controller connects the temperature sensor, valves, and the main heating system to realize intelligent scheduling of the entire system.

[0034] In this embodiment, the number of hot presses can be set to 3; at this time, the hot presses are 1a, 1b and 1c respectively; it is understood that setting the number of hot presses to 3 is just an example, and the specific number of hot presses can be set according to the requirements.

[0035] When hot presses 1a and 1b have just finished pressing a batch of products and are waiting for or starting to cool down, hot press 1c is loaded with a new batch of products to be pressed. Since hot presses 1a and 1b have just finished pressing a batch of products, their internal heat transfer oil temperature is high; while the internal heat transfer oil temperature of hot press 1c is low. Therefore, the heat transfer oil from hot presses 1a and 1b can be used sequentially to preheat hot press 1c, thereby recovering and utilizing the heat energy from hot presses 1a and 1b. This reduces energy consumption during the main heating stage and improves the energy efficiency of the entire equipment cluster.

[0036] For example: The process requires hot pressing PP material from T1=30°C to T2=180°C. Hot presses 1a and 1b have just finished pressing, and the internal hot oil temperature is approximately 180°C. Hot press 1c has finished loading and needs to be heated. To recover and utilize the heat energy of the high-temperature heat transfer oil in the hot press, the controller first controls the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to hot press 1b, and the third branch pipe 207 and the connecting pipe 208 corresponding to hot press 1c to open, and starts the heat transfer oil circulation pump, so that the heat transfer oil in hot press 1b and hot press 1c is mixed evenly, and the temperature of the heat transfer oil in hot press 1c rises to T_int_1; then controls the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to hot press 1a, and the third branch pipe 207 and the connecting pipe 208 corresponding to hot press 1c to open, and starts the heat transfer oil circulation pump 212, so that the temperature of the heat transfer oil in hot press 1c rises to T_int_2; after preheating is completed, the main heating system of hot press 1c itself is started to heat the heat transfer oil from T_int_2 to T2.

[0037] It should be noted that the present invention can use two hot presses to preheat the heat transfer oil in one of the hot presses, or it can use one hot press to preheat the heat transfer oil in the other hot press. Those skilled in the art can determine the appropriate method based on the actual situation. The present invention does not impose any specific limitations, and all of these are within the scope of protection of this application.

[0038] Example 3 This invention also provides a deep energy recovery method based on multi-stage serial preheating, comprising the following steps: Step S101: When an intermittent heating unit needs to start its heating cycle, it is designated as the target unit. One or more intermittent heating units that can currently serve as heat sources are identified and designated as source units. A serial execution sequence is planned to preheat the target unit using the identified intermittent heating units. Step S102: The heat transfer network is controlled to execute each preheating sub-process. In each preheating sub-process, a heat transfer path is established from the intermittent heating unit in the current serial execution sequence to the target unit, and heat transfer is performed until the preset termination condition for that preheating stage is met. Step S103: Repeat step S102 until all planned intermittent heating units in the sequence have preheated the target unit, so that the target unit reaches the preheating endpoint temperature; Step S104: Start the main heating system of the target unit and heat it from the preheating endpoint temperature to the target high temperature, so that the energy consumption of the main heating system of the target unit is close to 1 / 2^(N-1) of the basic energy consumption E0, where the basic energy consumption E0 is the energy consumption corresponding to the main heating system directly heating the target unit from the preset low temperature to the target high temperature, and N is the number of intermittent heating units; Step S105: Update the state of the target unit that has completed heating to a potential source unit so that it can participate in the preheating of other intermittent heating units during the subsequent cooling process, thereby maintaining the steady-state energy cycle of the system. It should be noted that intermittent heating units include, but are not limited to, ovens or hot presses; the heat transfer network can be... Figure 1 The aforementioned heat transfer network.

[0039] Optionally, step S102 specifically includes: Precisely control the relevant valves in the heat transfer network, open the heat transfer channel from the source unit to the target unit in the current sequence, and start or adjust the relevant heat transfer oil circulation pumps or fans; It should be noted that when the intermittent unit is an oven, opening the heat transfer channel from the source unit to the target unit in the current sequence specifically includes: opening the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to the source unit, and opening the valves on the third branch pipe 207 and the connecting pipe 208 corresponding to the target unit, and starting the fan. When the intermittent unit is a hot press, opening the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to the source unit, and opening the valves on the third branch pipe 207 and the connecting pipe 208 corresponding to the target unit, and starting the heat transfer oil circulation pump.

[0040] Monitor the temperature rise rate and real-time temperature of the target unit, as well as the temperature fall rate of the source unit; dynamically adjust the valve opening or the speed of the heat transfer oil circulation pump and fan to control the heat transfer rate; Determine whether the preheating between the source unit and the target unit in the current sequence has reached the preheating termination condition; If so, shut down the heat transfer channel from the source unit to the target unit in the current sequence, and shut down the corresponding heat transfer oil circulation pump or fan.

[0041] As described above, when the intermittent unit is an oven, closing the heat transfer channel from the source unit to the target unit in the current sequence specifically includes: closing the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to the source unit, and closing the valves on the third branch pipe 207 and the connecting pipe 208 corresponding to the target unit, and turning off the fan. When the intermittent unit is a hot press, closing the valves on the first branch pipe 205 and the second branch pipe 206 corresponding to the source unit, and closing the valves on the third branch pipe 207 and the connecting pipe 208 corresponding to the target unit, and turning off the heat transfer oil circulation pump.

[0042] The preset termination conditions for each stage of preheating include: the temperature of the target unit reaches the preset intermediate target value for that stage of preheating, or the temperature difference between the target unit and the current source unit is less than a preset threshold, or the maximum allowable preheating duration for that stage is reached, or the temperature of the current source unit is lower than its minimum allowable temperature as an effective heat source.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0044] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0045] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application. Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A deep energy recovery system based on multi-stage serial preheating, characterized in that, include: N intermittent heating units; A heat transfer network, which is configured to establish independent heat transfer paths between the N intermittent heating units; The sensor group is used to monitor the operating status of the intermittent heating unit and the heat transfer network; as well as A controller is provided to monitor the operating status of the N intermittent heating units in real time. When a target unit needs to start a heating cycle from a preset low temperature, the controller identifies one or more intermittent heating units that can be used as heat sources as source units. The controller controls the heat transfer network so that the target unit receives heat input from at least one and at most N-1 identified source units sequentially and serially to complete a multi-stage preheating process until the target unit reaches the preheating endpoint temperature. After completing the multi-stage preheating process, the controller starts the main heating system of the target unit itself to heat it from the preheating endpoint temperature to the target high temperature, so that the energy consumption of the main heating system of the target unit is close to 1 / 2^(N-1) of the basic energy consumption E0, where the basic energy consumption E0 is the energy consumption corresponding to the main heating system directly heating the target unit from the preset low temperature to the target high temperature.

2. The deep energy recovery system based on multi-stage serial preheating according to claim 1, characterized in that: The intermittent heating unit is configured as an oven or a hot press.

3. A deep energy recovery system based on multi-stage serial preheating according to claim 2, characterized in that: When the intermittent heating unit is an oven, the heat transfer network includes a first main pipe (201), a second main pipe (202), an actuator (203), and a third main pipe (204). The second main pipe (202) is connected to the input end of the actuator (203), and the third main pipe (204) is connected to the output end of the actuator (203). The actuator (203) is a fan. The first main pipe (201), the second main pipe (202), and the third main pipe (204) are respectively provided with a first branch pipe (205), a second branch pipe (206), and a third branch pipe (207) corresponding to the intermittent heating unit. The first branch pipe (205), the second branch pipe (206), and the third branch pipe (207) are all provided with valves, and the first branch pipe (205) and the third branch pipe (207) are respectively located on both sides of the intermittent heating unit.

4. A deep energy recovery system based on multi-stage serial preheating according to claim 2, characterized in that: Both the first branch pipe (205) and the second branch pipe (206) are equipped with tee pipes, and the tee pipes corresponding to the first branch pipe (205) and the second branch pipe (206) are fixedly connected together by a connecting pipe (208), and a valve is also provided on the connecting pipe (208); the third branch pipe (207) is also equipped with a tee pipe, and the end of the first branch pipe (205) away from the first main pipe (201) is connected to the tee pipe.

5. A deep energy recovery system based on multi-stage serial preheating according to claim 2, characterized in that: When the intermittent heating unit is a hot press, the heat transfer network includes a first main pipe (201), a second main pipe (202), an actuator (203), and a third main pipe (204). The second main pipe (202) is connected to the input end of the actuator (203), and the third main pipe (204) is connected to the output end of the actuator (203). The actuator (203) is a heat transfer oil pump. The first main pipe (201), the second main pipe (202), and the third main pipe (204) are respectively equipped with a first branch corresponding to the intermittent heating unit. Pipe (205), second branch pipe (206) and third branch pipe (207), valves are provided on the first branch pipe (205), the second branch pipe (206) and the third branch pipe (207), and the first branch pipe (205) and the third branch pipe (207) are respectively located on both sides of the intermittent heating unit; a three-way pipe is provided on the first branch pipe (205) and the second branch pipe (206), and the three-way pipes corresponding to the first branch pipe (205) and the second branch pipe (206) are fixedly connected together by a connecting pipe (208), and a valve is also provided on the connecting pipe (208).

6. A deep energy recovery system based on multi-stage serial preheating according to claim 5, characterized in that: A tee pipe is also provided on the third branch pipe (207), and the end of the first branch pipe (205) away from the first main pipe (201) is connected to the tee pipe.

7. A deep energy recovery method based on multi-stage serial preheating, characterized in that, Includes the following steps: Step S101: When an intermittent heating unit needs to start its heating cycle, it is designated as the target unit. One or more intermittent heating units that can currently serve as heat sources are identified and designated as source units. A serial execution sequence is planned to preheat the target unit using the identified intermittent heating units. Step S102: The heat transfer network is controlled to execute each preheating sub-process. In each preheating sub-process, a heat transfer path is established from the intermittent heating unit in the current serial execution sequence to the target unit, and heat transfer is performed until the preset termination condition for that preheating stage is met. Step S103: Repeat step S102 until all planned intermittent heating units in the sequence have preheated the target unit, so that the target unit reaches the preheating endpoint temperature; Step S104: Start the main heating system of the target unit and heat it from the preheating endpoint temperature to the target high temperature, so that the energy consumption of the main heating system of the target unit is close to 1 / 2^(N-1) of the basic energy consumption E0, where the basic energy consumption E0 is the energy consumption corresponding to the main heating system directly heating the target unit from the preset low temperature to the target high temperature, and N is the number of intermittent heating units.

8. A deep energy recovery method based on multi-stage serial preheating according to claim 7, characterized in that: Step S102 specifically includes: Precisely control the relevant valves in the heat transfer network, open the heat transfer channel from the source unit to the target unit in the current sequence, and start or adjust the relevant heat transfer oil circulation pumps or fans; Monitor the temperature rise rate and real-time temperature of the target unit, as well as the temperature fall rate of the source unit; dynamically adjust the valve opening or the speed of the heat transfer oil circulation pump and fan to control the heat transfer rate; Determine whether the preheating between the source unit and the target unit in the current sequence has reached the preheating termination condition; If so, shut down the heat transfer channel from the source unit to the target unit in the current sequence, and shut down the corresponding heat transfer oil circulation pump or fan.

9. A deep energy recovery method based on multi-stage serial preheating according to claim 7 or 8, characterized in that, The preset termination conditions for each preheating stage include: the temperature of the target unit reaches the preset intermediate target value for that preheating stage; or the temperature difference between the target unit and the current source unit is less than a preset threshold; or the maximum allowable preheating duration for that stage is reached; or the temperature of the current source unit is lower than its minimum allowable temperature as an effective heat source.

10. A deep energy recovery method based on multi-stage serial preheating according to claim 7, characterized in that, Step S104 is followed by updating the state of the target unit that has completed heating to a potential source unit, so that it can participate in the preheating of other intermittent heating units during the subsequent cooling process, thereby maintaining the steady-state energy cycle of the system.

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