A control method, device and system for multi-source complementary integrated hot air

Abstract

The application discloses a kind of multi-source complementary integrated hot air control method, device and system, the method includes collecting the real-time operating parameter of each residual heat source in multi-source complementary integrated hot air station and the target temperature of hot air;Each real-time operating parameter is compared with preset working condition condition, and current working condition type is identified;According to working condition identification result matching determines target heat source distribution strategy;Based on the strategy, the input proportion of each residual heat source is adjusted and the heat exchange path is adjusted, and the output hot air is obtained by heating fresh air step by step;According to the deviation of actual outlet temperature and target temperature, adjust the heat source input, and obtain the corrected output hot air.The application is complementary to multiple residual heat sources by working condition identification and strategy matching, and closed-loop correction is carried out according to temperature deviation, solve the problem that existing hot air supply lacks unified coordination control of multiple residual heat sources, leading to large temperature fluctuation of hot air, realize residual heat integrated utilization and stable output of hot air temperature, improve the quality of spray drying product and reduce energy consumption.

Description

Technical Field

[0001] This invention relates to the field of energy control technology, and in particular to a control method, device and system for multi-source complementary integrated hot air. Background Technology

[0002] In the spray drying and flash drying processes of industries such as lithium batteries and food powders, a continuous supply of high-temperature hot air (150℃~220℃) is required as the drying medium, and the energy consumption for hot air preparation accounts for a significant portion of the total production energy consumption. Meanwhile, these factories typically have multiple recoverable waste heat sources: approximately 70%~85% of the electrical energy generated by the air compressor is converted into compression heat, most of which is dissipated through the cooling system; the steam heating system produces condensate at 90℃~100℃ after use, which is traditionally discharged directly; the spray drying tower emits high-temperature, high-humidity exhaust gas at 65℃~110℃, containing a large amount of sensible heat and latent heat of water vapor condensation, which is usually directly vented. Recovering these waste heat sources for use in the preparation of process hot air is an important way to reduce energy consumption in the drying process.

[0003] However, existing hot air supply methods lack unified identification and coordinated distribution control of multiple waste heat sources. Each waste heat source operates independently, and the recoverable heat from each source is directly affected by the production conditions. Changes in air compressor load, steam pressure fluctuations, and changes in the feed rate of the spray drying tower can all lead to unstable recovery of heat, resulting in drastic fluctuations in the supplied hot air temperature, typically reaching ±15℃. This makes it difficult to maintain a stable target temperature, directly affecting the particle size distribution and quality consistency of the spray-dried products. Summary of the Invention

[0004] This invention provides a control method, device, and system for multi-source complementary integrated hot air, aiming to solve the technical problem in the prior art where the lack of unified operating condition identification and coordinated distribution control of multiple waste heat sources leads to large fluctuations in hot air temperature, affecting product quality.

[0005] In a first aspect, embodiments of the present invention provide a control method for multi-source complementary integrated hot air, comprising: Real-time operating parameters of each waste heat source and the target temperature of the hot air in the multi-source complementary integrated hot air station are collected and summarized to obtain the operating dataset. The real-time operating parameters in the running dataset are compared with preset operating conditions to identify the current operating condition type and obtain the operating condition identification result. Based on the operating condition identification result, a strategy corresponding to the current operating condition type is matched from a variety of preset heat source allocation strategies and determined as the target heat source allocation strategy. Based on the target heat source allocation strategy, the input ratio and heat exchange path of each waste heat source are adjusted, and the fresh air is heated step by step to obtain output hot air. Monitor the actual outlet temperature of the output hot air, and adjust the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

[0006] Secondly, embodiments of the present invention provide a control device for multi-source complementary integrated hot air, comprising: The data acquisition module is used to collect the real-time operating parameters of each waste heat source in the multi-source complementary integrated hot air station and the target temperature of the hot air, and summarize them to obtain the operating dataset. The working condition identification module is used to compare each of the real-time operating parameters in the running dataset with preset working condition conditions in order to identify the current working condition type and obtain the working condition identification result. The strategy determination module is used to match the strategy corresponding to the current working condition type from a variety of preset heat source allocation strategies based on the working condition identification results, and determine it as the target heat source allocation strategy. The heating control module is used to adjust the input ratio and heat exchange path of each of the waste heat sources based on the target heat source allocation strategy, and to heat the fresh air step by step to obtain output hot air. The dynamic adjustment module is used to monitor the actual outlet temperature of the output hot air and adjust the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

[0007] Thirdly, embodiments of the present invention provide a control system for multi-source complementary integrated hot air, including the control device for multi-source complementary integrated hot air as described in the second aspect, and further including: The waste heat recovery module includes an air compressor waste heat recovery unit, a steam condensate waste heat recovery unit, and a spray drying tower exhaust gas waste heat recovery unit. The heat energy enhancement module includes an industrial high-temperature heat pump unit. The heat medium outlets of the air compressor waste heat recovery unit and the steam condensate waste heat recovery unit are connected in parallel and then connected to the evaporator inlet of the industrial high-temperature heat pump unit. The hot air output module includes a fresh air preheater and a hot air buffer tank. The hot air outlet of the waste heat recovery unit of the spray drying tower tail gas and the condenser outlet of the industrial high temperature heat pump unit are respectively connected to the first-stage preheating inlet and the second-stage preheating inlet of the fresh air preheater. The hot air outlet of the fresh air preheater outputs the hot air through the hot air buffer tank. An intelligent control module, comprising a PLC controller and an actuator, wherein the control device is disposed within the PLC controller and the PLC controller is connected to the actuator.

[0008] This invention provides a control method for multi-source complementary integrated hot air, comprising: collecting real-time operating parameters of each waste heat source in a multi-source complementary integrated hot air station and the target temperature of the hot air, and summarizing them to obtain an operating dataset; comparing each real-time operating parameter in the operating dataset with preset operating conditions to identify the current operating condition type and obtain an operating condition identification result; matching the strategy corresponding to the current operating condition type from a preset variety of heat source allocation strategies according to the operating condition identification result, and determining it as the target heat source allocation strategy; adjusting the input ratio and heat exchange path of each waste heat source based on the target heat source allocation strategy, and heating the fresh air step by step to obtain output hot air; monitoring the actual outlet temperature of the output hot air, and adjusting the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air. This invention collects real-time operating parameters of each waste heat source and identifies the current operating condition. It matches and determines the target heat source allocation strategy from a set of preset heat source allocation strategies. Based on this, it dynamically adjusts the input ratio and heat exchange path of each waste heat source and heats the fresh air step by step. Then, it performs closed-loop correction of heat source input based on the deviation between the actual outlet temperature of the output hot air and the target temperature. This achieves unified and coordinated control and complementary utilization of multiple waste heat sources, effectively suppressing the instability of heating caused by fluctuations in production conditions. It keeps the temperature of the output hot air stable near the target temperature, solving the technical problem in the prior art where the lack of unified identification and coordinated allocation control of multiple waste heat sources leads to large fluctuations in hot air temperature and affects product quality. This ensures the consistency of spray-dried product quality, while fully recovering and utilizing waste heat and reducing the energy consumption of hot air preparation.

[0009] This invention also provides a control device and system for multi-source complementary integrated hot air, which also has the above-mentioned beneficial effects. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A flowchart illustrating a control method for multi-source complementary integrated hot air provided in an embodiment of the present invention; Figure 2 A schematic block diagram of a control device for multi-source complementary integrated hot air provided in an embodiment of the present invention; Figure 3 This is a schematic block diagram of a multi-source complementary integrated hot air control system provided in an embodiment of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0014] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0015] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0016] Please see below. Figure 1 , Figure 1 The flowchart of a multi-source complementary integrated hot air control method provided in an embodiment of the present invention specifically includes steps S101 to S105.

[0017] S101. Collect the real-time operating parameters of each waste heat source in the multi-source complementary integrated hot air station and the target temperature of the hot air, and summarize them to obtain the operating dataset. S102. Compare each of the real-time operating parameters in the running dataset with the preset operating conditions to identify the current operating condition type and obtain the operating condition identification result. S103. Based on the operating condition identification result, match the strategy corresponding to the current operating condition type from a variety of preset heat source allocation strategies, and determine it as the target heat source allocation strategy. S104. Based on the target heat source allocation strategy, adjust the input ratio and heat exchange path of each waste heat source, and heat the fresh air step by step to obtain output hot air. S105. Monitor the actual outlet temperature of the output hot air, and adjust the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

[0018] In step S101, the multi-source complementary integrated hot air station refers to an integrated hot air supply device that integrates and recovers various waste heat sources in a multi-source complementary manner, thereby heating fresh air and stably outputting process hot air. Multi-source complementarity refers to the integrated recovery and complementary utilization of two or more waste heat sources of different grades through a coupled heat exchange network. Grade is used to characterize the level of thermal energy temperature. Waste heat source refers to the source of waste heat generated during the production process that can be recovered and utilized. Real-time operating parameters refer to real-time parameters such as temperature, flow rate, and pressure that reflect the current usability of each waste heat source. The target temperature of the hot air refers to the set temperature of the hot air required by the downstream drying process. Summarizing the above parameters collected in real time yields an operating dataset, which provides a complete and reliable data foundation for subsequent operating condition identification.

[0019] In one embodiment, step S101 includes: The following data were collected: the first outlet water temperature of the air compressor waste heat recovery unit, the second outlet water temperature of the steam condensate waste heat recovery unit, the exhaust temperature and relative humidity of the spray drying tower tail gas, the fresh air temperature, the target temperature of the hot air, the inlet temperature of the heat pump unit evaporator, and the outlet temperature of the condenser. All collected parameters are validated and outliers are removed, and the resulting dataset is compiled.

[0020] In this embodiment, for ease of description, the first outlet water temperature of the air compressor waste heat recovery unit is denoted as T1, the second outlet water temperature of the steam condensate waste heat recovery unit is denoted as T2, the exhaust air temperature of the spray drying tower tail gas is denoted as T3, the relative humidity is denoted as RH3, the fresh air temperature is denoted as T0, the target temperature of the hot air is denoted as T_set, and the inlet temperature of the heat pump unit evaporator is denoted as T_set. e The outlet temperature of the condenser is denoted as T_in and T_c_out. The air compressor waste heat recovery unit recovers the compression heat generated during air compressor operation; the first outlet water temperature T1 is typically between 80℃ and 95℃. The steam condensate waste heat recovery unit recovers the sensible heat from the condensate generated after steam use; the second outlet water temperature T2 is typically between 90℃ and 100℃. Spray drying tower exhaust gas refers to the high-temperature, high-humidity waste gas emitted from the spray drying tower; the exhaust temperature T3 is typically between 65℃ and 110℃, and the relative humidity RH3 reflects the water vapor content in the exhaust gas. Both are used to determine the recycling value of the exhaust gas. The fresh air temperature T0 is the temperature of the ambient fresh air to be heated, for example, 20℃. The target temperature T_set can be set according to the requirements of the downstream drying process, for example, set to 140℃ to 150℃. The heat pump unit refers to a device that uses electrical energy to raise lower-temperature heat energy to a higher temperature; its evaporator inlet temperature T_c_out is... e The values ​​_in and condenser outlet temperature T_c_out are used to reflect the operating status of the heat pump unit.

[0021] After collecting the above parameters, the validity of all collected parameters is verified. For example, it is verified whether each parameter is within the range of the corresponding sensor and whether there are any instantaneous jumps that significantly deviate from the normal range. Values ​​that exceed the range or are obviously abnormal are discarded as outliers, thereby ensuring the accuracy and reliability of the running dataset and avoiding interference from abnormal data to subsequent working condition identification.

[0022] In step S102, the preset operating conditions refer to the pre-set comparison conditions used to determine the current availability of each waste heat source. The operating condition type is used to characterize the overall heating capacity and availability of each waste heat source at the current moment. In actual production, changes in air compressor load, steam pressure fluctuations, and changes in the feed rate of the spray drying tower will all cause changes in the recoverable heat of each waste heat source. By comparing each real-time operating parameter in the operating dataset with the preset operating conditions one by one, the current operating condition type can be identified in a timely and accurate manner. The obtained operating condition identification result provides a basis for judgment on the matching of subsequent heat source allocation strategies.

[0023] In one embodiment, step S102 includes: Extract the first outlet water temperature, the second outlet water temperature, the exhaust air temperature, and the relative humidity from the running dataset, respectively; When the first outlet water temperature is not lower than the first preset temperature and the second outlet water temperature is not lower than the second preset temperature, it is determined to be a high-grade heat source sufficient working condition. When the first outlet water temperature is lower than the first preset temperature or the second outlet water temperature is lower than the third preset temperature, it is determined to be a heat source insufficient condition. If the exhaust temperature is not lower than the first preset temperature and the relative humidity is not lower than the preset percentage, then the latent heat of the exhaust gas is determined to be usable. The working condition types and corresponding judgment times obtained from each judgment are summarized and recorded to generate working condition identification results.

[0024] In this embodiment, the first preset temperature, the second preset temperature, the third preset temperature, and the preset percentage can all be preset according to actual engineering needs. For example, the first preset temperature is set to 80℃, the second preset temperature is set to 95℃, the third preset temperature is set to 90℃, and the preset percentage is set to 20%. The "high-grade heat source sufficient" condition indicates that the temperatures of both the air compressor waste heat and the steam condensate waste heat are at a high level, requiring no further heating. The "heat source insufficient" condition indicates that the temperature of at least one waste heat source is low, resulting in insufficient recoverable heat, necessitating further heating of the waste heat. The "exhaust gas latent heat usable" condition indicates that the temperature and humidity of the spray drying tower exhaust gas are high, and in addition to sensible heat, the exhaust gas contains a large amount of water vapor condensation latent heat, which has recovery and utilization value. Since the exhaust gas latent heat usable condition is determined independently based on exhaust temperature and relative humidity, it can coexist with the aforementioned two conditions.

[0025] For example, when the first outlet water temperature T1 is 88℃ and the second outlet water temperature T2 is 97℃, it is determined to be a high-grade heat source sufficient condition; when T1 is 76℃ or T2 is 85℃, it is determined to be a heat source insufficient condition; based on this, if the exhaust air temperature T3 is 85℃ and the relative humidity RH3 is 35%, then the condition of usable latent heat in the exhaust gas is superimposed. The condition types obtained from each determination and the corresponding determination times are summarized and recorded to generate the condition identification results, which facilitates subsequent strategy matching and also facilitates the traceability analysis of the condition change process.

[0026] In step S103, the heat source allocation strategy refers to a control strategy that comprehensively arranges whether each waste heat source is put into operation, the order of its input, the proportion of its input, and the heat exchange path through which heat is transferred. Different operating conditions correspond to different waste heat availability states, and the applicable heat source allocation strategies are also different. By setting corresponding heat source allocation strategies for each operating condition type in advance, and matching them according to the operating condition identification results during operation, a target heat source allocation strategy suitable for the current operating condition type can be determined, so that the utilization mode of each waste heat source is always consistent with its actual availability state.

[0027] In one embodiment, step S103 includes: The working condition identification results are analyzed to extract the working condition type determined at the current moment and obtain the strategy matching conditions; If the strategy matching condition is that the high-grade heat source is sufficient, then the first strategy is to prioritize direct heating of the waste heat of the generated steam condensate. If the strategy matching condition is the insufficient heat source condition, then a second strategy is generated to simultaneously activate the waste heat from the air compressor and the waste heat from the steam condensate, and the heat pump unit is at full load. If the strategy matching conditions are superimposed with the operating condition containing the latent heat of exhaust gas, then the third strategy of preheating fresh air with exhaust gas is superimposed. The first, second, and third strategies are combined according to priority and the execution parameters are configured to determine the target heat source allocation strategy.

[0028] In this embodiment, the first strategy corresponds to the condition of sufficient high-grade heat source. Under the first strategy, the waste heat of steam condensate with a higher temperature (e.g., not lower than 95°C) is preferentially used to directly heat the fresh air, and the waste heat of the air compressor (e.g., not lower than 85°C) is used as a supplementary heat source. The heat pump unit can operate at low load or be shut down to reduce power consumption. The second strategy corresponds to the condition of insufficient heat source. Under the second strategy, the waste heat of the air compressor and the waste heat of steam condensate are put into use at the same time, and the heat pump unit operates at full load to raise the temperature of the two types of waste heat to the required heating temperature level to make up for the problem of insufficient heat recovery from a single waste heat source. The third strategy corresponds to the condition of usable latent heat of exhaust gas. Since this condition can be superimposed with the first two conditions, the third strategy is executed in a superimposed manner. That is, the exhaust gas of the spray drying tower is first used to preheat the fresh air, raising the temperature of the fresh air by 15°C to 25°C. Then, the heat source corresponding to the first strategy or the second strategy continues to heat the preheated fresh air, thereby reducing the heat demand of subsequent heating links.

[0029] When combining the above strategies by priority, they can be connected in the order of preheating the exhaust gas first and then heating with the main heat source. Corresponding execution parameters are configured for each strategy, such as the input order and input ratio of each waste heat source and the load rate of the heat pump unit. The combined strategy and its execution parameters are determined as the target heat source allocation strategy.

[0030] In step S104, the input ratio refers to the proportion of heat provided by each waste heat source to the fresh air heating process, and the heat exchange path refers to the heat exchange stages and their sequence through which the heat from each waste heat source is transferred to the fresh air. Adjusting the input ratio and heat exchange path based on the target heat source allocation strategy allows waste heat sources of different grades to be used to their fullest potential, achieving tiered utilization and complementary allocation of heat; step-by-step heating of fresh air means that the fresh air flows through multiple heat exchange stages in sequence, with the temperature gradually increasing until it reaches the temperature level required by the process, thereby obtaining the output hot air.

[0031] In one embodiment, step S104 includes: An adjustment command is generated based on the target heat source allocation strategy; wherein the adjustment command can adjust the electric regulating valve, the variable frequency fan, and the variable frequency water pump; In response to the adjustment command, the flow rate and input ratio of the medium corresponding to the waste heat source are adjusted, and the input low-grade waste heat is raised to the preset temperature range by the heat pump unit to obtain medium-temperature heat energy. Fresh air is sequentially sent through the exhaust gas preheater and the condenser of the heat pump unit, and heated step by step using the medium-temperature thermal energy. The heated fresh air is then sent to the hot air buffer tank for temporary storage, and finally output as hot air through the hot air buffer tank.

[0032] In this embodiment, low-grade waste heat refers to waste heat resources with low temperatures (usually below 150°C) that are difficult to use directly in high-temperature processes such as spray drying. The waste heat from the air compressor and steam condensate used in this embodiment are examples of low-grade waste heat, with temperatures typically between 50°C and 100°C. The heat pump unit absorbs the heat from the low-grade waste heat through the evaporator, compresses it to increase its temperature, and then releases it through the condenser, thereby raising the low-grade waste heat to a preset temperature range, such as 120°C to 150°C, to obtain medium-temperature heat energy. Specifically, after generating adjustment commands based on the target heat source allocation strategy, the on / off state and flow rate of the heat medium for each waste heat source are adjusted via an electric regulating valve, the circulation flow rate of the heat medium is adjusted via a variable frequency water pump, and the corresponding air volume is adjusted via a variable frequency fan, thereby achieving the adjustment of the medium flow rate and input ratio for each waste heat source.

[0033] In the process of heating fresh air in stages, the fresh air first enters the exhaust gas preheater, which is a heat exchanger that uses the heat from the exhaust gas of the spray drying tower to preheat the fresh air; for example, a gas-to-gas heat exchanger can be used. The preheated fresh air then enters the condenser of the heat pump unit, where it is further heated using medium-temperature thermal energy. Subsequently, the heated fresh air is sent to a hot air buffer tank for temporary storage. The hot air buffer tank is used to store hot air at a stable temperature, mitigating the impact of operating condition fluctuations on the hot air temperature. Finally, the hot air is output from the hot air buffer tank. For example, ambient fresh air at 20°C can be preheated by the exhaust gas preheater to a temperature increase of 15°C to 25°C, and then heated by the condenser of the heat pump unit to a target temperature close to, for example, 140°C to 150°C.

[0034] In step S105, since the heating capacity of each waste heat source changes in real time with the production conditions, it is still difficult to completely eliminate the temperature fluctuation of the output hot air by simply adjusting according to the target heat source allocation strategy. Therefore, it is necessary to continuously monitor the actual outlet temperature of the output hot air and reverse the heat source input according to the deviation between the actual outlet temperature and the target temperature to form a closed-loop control, so that the temperature of the output hot air is always stable near the target temperature, providing a temperature-stable drying medium for the downstream drying process.

[0035] In one embodiment, step S105 includes: The actual outlet temperature of the output hot air in the hot air buffer tank is collected according to a preset adjustment cycle; The temperature deviation is obtained by subtracting the target temperature from the actual outlet temperature. When the temperature deviation is greater than the fourth preset temperature, the load of the heat pump unit is reduced or the flow rate of the medium input to the waste heat source is reduced. When the temperature deviation is less than the fifth preset temperature, increase the load of the heat pump unit or increase the flow rate of the medium input to the waste heat source; Repeat the above adjustments until the absolute value of the temperature deviation is within the preset value, and obtain the corrected output hot air.

[0036] In this embodiment, the preset adjustment cycle can be set to 30 to 60 seconds, meaning that the actual outlet temperature at the hot air buffer tank outlet is collected every 30 to 60 seconds and an adjustment is performed. For ease of description, the actual outlet temperature is denoted as T_out, and the temperature deviation is denoted as ΔT, where ΔT = T_out - T_set. The fourth and fifth preset temperatures are used to define the allowable temperature deviation range. For example, the fourth preset temperature is set to 5°C, and the fifth preset temperature is set to -5°C: when the temperature deviation ΔT is greater than 5°C, it indicates that the temperature of the output hot air is too high. In this case, the load of the heat pump unit is reduced or the flow rate of the waste heat source medium is reduced to decrease the heating amount; when the temperature deviation ΔT is less than -5°C, it indicates that the temperature of the output hot air is too low. In this case, the load of the heat pump unit is increased or the flow rate of the waste heat source medium is increased to increase the heating amount. Repeat the above adjustments until the absolute value of the temperature deviation is within the preset value, for example, 3℃, so that the temperature of the output hot air is stable within the range of ±3℃ of the target temperature; for applications requiring higher temperature control accuracy, the preset value can also be 2℃.

[0037] For example, if the target temperature T_set is 150℃, and the actual outlet temperature T_out collected in a certain adjustment cycle is 156℃, then the temperature deviation ΔT is 6℃, which is greater than 5℃. In this case, the load of the heat pump unit should be reduced or the medium flow rate should be decreased. If T_out is 143℃, then ΔT is -7℃, which is less than -5℃. In this case, the load of the heat pump unit should be increased or the medium flow rate should be increased. This adjustment is repeated until T_out is within the range of 147℃ to 153℃. Compared with the traditional single heat source method, which has hot air temperature fluctuations of up to ±15℃, this embodiment can control the hot air temperature fluctuation within ±3℃, significantly improving the stability of the hot air temperature and thus ensuring the consistency of the downstream spray-dried product quality.

[0038] In one embodiment, the control method for multi-source complementary integrated hot air further includes: During the output of the corrected hot air, the operating status of each waste heat source recovery unit is periodically detected; The operating states are compared with the recorded fault criteria to identify the waste heat source recovery unit that has malfunctioned, and the faulty waste heat source is obtained. The recovery unit corresponding to the faulty waste heat source is disconnected, and the corresponding heat load is redistributed to the remaining waste heat sources. If the available heat from the remaining waste heat sources is still insufficient after redistribution, switch to the auxiliary heating mode supplied by the auxiliary heater, and update the target heat source allocation strategy simultaneously.

[0039] In this embodiment, the operating status includes the status of parameters such as medium temperature, medium flow rate, pressure, and sensor signals of each recovery unit; the fault criteria refer to pre-recorded conditions used to determine whether a recovery unit has malfunctioned, such as the outlet water temperature continuously falling below the lower limit of the normal range, the medium flow rate being zero for an extended period, or the sensor signal being lost or exceeding its range. By comparing each operating status obtained from periodic detection with the fault criteria one by one, the recovery unit of the waste heat source that has malfunctioned can be identified, thus obtaining the faulty waste heat source.

[0040] After identifying a faulty waste heat source, its corresponding recovery unit is removed from the current heat exchange network, and its original heat load is redistributed to other waste heat sources. This means increasing the proportion of other waste heat sources in operation to maintain a relatively constant total heating output. If the available heat from these redistributed sources is still insufficient to heat the output hot air to the target temperature, the system switches to an auxiliary heating mode, where auxiliary heaters (e.g., electric heaters) supplement the fresh air heating when waste heat is insufficient. Simultaneously, the target heat source allocation strategy is updated to ensure subsequent adjustments are consistent with the currently available heat source configuration. This fault identification and switching process can be completed within 30 seconds. Therefore, even if a waste heat source fluctuates or fails, the system can still guarantee a continuous and stable supply of hot air, ensuring production continuity and reducing losses caused by unplanned downtime.

[0041] In summary, the multi-source complementary integrated hot air control method provided by the embodiments of the present invention collects the real-time operating parameters of each waste heat source and identifies the operating condition type, matches and determines the target heat source allocation strategy, dynamically adjusts the input ratio and heat exchange path of each waste heat source and heats the fresh air step by step, and then performs closed-loop correction based on the deviation between the actual outlet temperature and the target temperature, integrating multiple waste heat sources into a complementary heat energy closed loop, that is, recovering the waste heat emitted in industrial production, raising the temperature and reusing it for the production process, forming a heat recycling. Using this method, hot air temperature fluctuations can be controlled within ±3℃, far superior to the ±15℃ fluctuation level of traditional single heat source methods. This significantly improves the particle size distribution consistency and quality stability of spray-dried products such as lithium iron phosphate and protein powder. Simultaneously, the complementary utilization of multiple waste heat sources achieves a comprehensive energy saving rate of over 60%. Taking a 70,000 m³ / h spray drying tower in a fluorochemical PVDF (polyvinylidene fluoride) production line as an example, the steam consumption before the modification was 3.8 tons / hour. After multi-source complementary modification using this method, the steam consumption was reduced to 0.3 tons / hour, saving approximately 3.6 million yuan in steam costs annually and reducing annual carbon emissions by approximately 67%. This method can also support applications for green factory certification and energy-saving technological transformation subsidies. It can be widely applied to hot air supply systems for spray drying and flash drying in industries such as lithium batteries and food powders.

[0042] Combination Figure 2 As shown, Figure 2 This is a schematic block diagram of a control device for multi-source complementary integrated hot air provided in an embodiment of the present invention. The control device 200 for multi-source complementary integrated hot air includes: The data acquisition module 201 is used to collect the real-time operating parameters of each waste heat source in the multi-source complementary integrated hot air station and the target temperature of the hot air, and summarize them to obtain the operating dataset. The working condition identification module 202 is used to compare each of the real-time operating parameters in the running dataset with preset working condition conditions in order to identify the current working condition type and obtain the working condition identification result. The strategy determination module 203 is used to match the strategy corresponding to the current working condition type from a variety of preset heat source allocation strategies based on the working condition identification result, and determine it as the target heat source allocation strategy. The heating control module 204 is used to adjust the input ratio and heat exchange path of each of the waste heat sources based on the target heat source allocation strategy, and to heat the fresh air step by step to obtain output hot air. The dynamic adjustment module 205 is used to monitor the actual outlet temperature of the output hot air, and adjust the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

[0043] In this embodiment, the data acquisition module 201 acquires the real-time operating parameters of each waste heat source in the multi-source complementary integrated hot air station and the target temperature of the hot air, and summarizes them to obtain an operating dataset; the operating condition identification module 202 compares each of the real-time operating parameters in the operating dataset with preset operating conditions to identify the current operating condition type and obtain an operating condition identification result; the strategy determination module 203 matches the strategy corresponding to the current operating condition type from a variety of preset heat source allocation strategies according to the operating condition identification result and determines it as the target heat source allocation strategy; the heating control module 204 adjusts the input ratio and heat exchange path of each waste heat source based on the target heat source allocation strategy, and heats the fresh air step by step to obtain output hot air; the dynamic adjustment module 205 monitors the actual outlet temperature of the output hot air, and adjusts the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

[0044] In one embodiment, the data acquisition module 201 is specifically used for: The following data were collected: the first outlet water temperature of the air compressor waste heat recovery unit, the second outlet water temperature of the steam condensate waste heat recovery unit, the exhaust temperature and relative humidity of the spray drying tower tail gas, the fresh air temperature, the target temperature of the hot air, the inlet temperature of the heat pump unit evaporator, and the outlet temperature of the condenser. All collected parameters are validated and outliers are removed, and the resulting dataset is compiled.

[0045] In one embodiment, the working condition identification module 202 is specifically used for: Extract the first outlet water temperature, the second outlet water temperature, the exhaust air temperature, and the relative humidity from the running dataset, respectively; When the first outlet water temperature is not lower than the first preset temperature and the second outlet water temperature is not lower than the second preset temperature, it is determined to be a high-grade heat source sufficient working condition. When the first outlet water temperature is lower than the first preset temperature or the second outlet water temperature is lower than the third preset temperature, it is determined to be a heat source insufficient condition. If the exhaust temperature is not lower than the first preset temperature and the relative humidity is not lower than the preset percentage, then the latent heat of the exhaust gas is determined to be usable. The working condition types and corresponding judgment times obtained from each judgment are summarized and recorded to generate working condition identification results.

[0046] In one embodiment, the strategy determination module 203 is specifically used for: The working condition identification results are analyzed to extract the working condition type determined at the current moment and obtain the strategy matching conditions; If the strategy matching condition is that the high-grade heat source is sufficient, then the first strategy is to prioritize direct heating of the waste heat of the generated steam condensate. If the strategy matching condition is the insufficient heat source condition, then a second strategy is generated to simultaneously activate the waste heat from the air compressor and the waste heat from the steam condensate, and the heat pump unit is at full load. If the strategy matching conditions are superimposed with the operating condition containing the latent heat of exhaust gas, then the third strategy of preheating fresh air with exhaust gas is superimposed. The first, second, and third strategies are combined according to priority and the execution parameters are configured to determine the target heat source allocation strategy.

[0047] In one embodiment, the heating control module 204 is specifically used for: An adjustment command is generated based on the target heat source allocation strategy; wherein the adjustment command can adjust the electric regulating valve, the variable frequency fan, and the variable frequency water pump; In response to the adjustment command, the flow rate and input ratio of the medium corresponding to the waste heat source are adjusted, and the input low-grade waste heat is raised to the preset temperature range by the heat pump unit to obtain medium-temperature heat energy. Fresh air is sequentially sent through the exhaust gas preheater and the condenser of the heat pump unit, and heated step by step using the medium-temperature thermal energy. The heated fresh air is then sent to the hot air buffer tank for temporary storage, and finally output as hot air through the hot air buffer tank.

[0048] In one embodiment, the dynamic adjustment module 205 is specifically used for: The actual outlet temperature of the output hot air in the hot air buffer tank is collected according to a preset adjustment cycle; The temperature deviation is obtained by subtracting the target temperature from the actual outlet temperature. When the temperature deviation is greater than the fourth preset temperature, the load of the heat pump unit is reduced or the flow rate of the medium input to the waste heat source is reduced. When the temperature deviation is less than the fifth preset temperature, increase the load of the heat pump unit or increase the flow rate of the medium input to the waste heat source; Repeat the above adjustments until the absolute value of the temperature deviation is within the preset value, and obtain the corrected output hot air.

[0049] In one embodiment, the control device 200 for the multi-source complementary integrated hot air is further configured to: During the output of the corrected hot air, the operating status of each waste heat source recovery unit is periodically detected; The operating states are compared with the recorded fault criteria to identify the waste heat source recovery unit that has malfunctioned, and the faulty waste heat source is obtained. The recovery unit corresponding to the faulty waste heat source is disconnected, and the corresponding heat load is redistributed to the remaining waste heat sources. If the available heat from the remaining waste heat sources is still insufficient after redistribution, switch to the auxiliary heating mode supplied by the auxiliary heater, and update the target heat source allocation strategy simultaneously.

[0050] Since the embodiments of the apparatus and the embodiments of the method correspond to each other, please refer to the description of the embodiments of the method for the embodiments of the apparatus, which will not be repeated here.

[0051] Combination Figure 3 As shown, this embodiment of the invention also provides a control system for multi-source complementary integrated hot air, including the control device for multi-source complementary integrated hot air as described above, and further including: The waste heat recovery module includes an air compressor waste heat recovery unit, a steam condensate waste heat recovery unit, and a spray drying tower exhaust gas waste heat recovery unit. The heat energy enhancement module includes an industrial high-temperature heat pump unit. The heat medium outlets of the air compressor waste heat recovery unit and the steam condensate waste heat recovery unit are connected in parallel and then connected to the evaporator inlet of the industrial high-temperature heat pump unit. The hot air output module includes a fresh air preheater and a hot air buffer tank. The hot air outlet of the waste heat recovery unit of the spray drying tower tail gas and the condenser outlet of the industrial high temperature heat pump unit are respectively connected to the first-stage preheating inlet and the second-stage preheating inlet of the fresh air preheater. The hot air outlet of the fresh air preheater outputs the hot air through the hot air buffer tank. An intelligent control module, comprising a PLC controller and an actuator, wherein the control device is disposed within the PLC controller and the PLC controller is connected to the actuator.

[0052] In this embodiment, the waste heat recovery module includes an air compressor waste heat recovery unit that may include a plate heat exchanger. This plate heat exchanger recovers heat from the air compressor's lubricating oil cooling system through a circulating heat medium. Since approximately 70% to 85% of the electrical energy is converted into compression heat during air compressor operation, recovering this heat can significantly reduce energy waste. In other embodiments, a shell-and-tube heat exchanger may be used instead of a plate heat exchanger in the air compressor waste heat recovery unit. The steam condensate waste heat recovery unit may include a condensate collection tank and a plate heat exchanger. The condensate collection tank collects the condensate generated after steam use, and the plate heat exchanger recovers the sensible heat from the condensate. The spray drying tower exhaust gas waste heat recovery unit may include a heat pipe heat exchanger. The heat pipe heat exchanger utilizes phase change heat transfer technology to recover the sensible heat and latent heat of condensation of water vapor in the high-humidity exhaust gas. In other embodiments, a plate heat exchanger may be used instead of a heat pipe heat exchanger in the spray drying tower exhaust gas waste heat recovery unit.

[0053] In the heat energy enhancement module, the industrial high-temperature heat pump unit refers to a heat pump unit that uses high-temperature heat pump technology to enhance low-grade waste heat into medium-grade heat energy. Its energy efficiency can be measured by the heat pump COP (Coefficient of Performance), which is the ratio of output heat to input electrical energy. The heat pump working fluid can be selected from R245fa, R1233zd, or other high-temperature working fluids according to the operating conditions. The heat medium outlets of the air compressor waste heat recovery unit and the steam condensate waste heat recovery unit are connected in parallel and then connected to the evaporator inlet of the industrial high-temperature heat pump unit. This allows the air compressor waste heat and steam condensate waste heat to be input individually or simultaneously, facilitating flexible allocation according to the target heat source distribution strategy. In other embodiments, series coupling can be used instead of parallel coupling for multi-heat source coupling.

[0054] In the hot air output module, the first-stage preheating inlet of the fresh air preheater is connected to the hot air outlet of the waste heat recovery unit of the spray drying tower exhaust gas, and the second-stage preheating inlet is connected to the condenser outlet of the industrial high-temperature heat pump unit. The ambient fresh air is heated step by step through the first-stage preheating and the second-stage preheating. The heated fresh air enters the hot air buffer tank. After the temperature fluctuation is smoothed by the hot air buffer tank, the output hot air with a stable temperature is supplied to downstream drying equipment such as the spray drying tower.

[0055] In the intelligent control module, the PLC controller refers to a controller built based on a PLC (Programmable Logic Controller), used to collect parameters such as temperature, flow rate, and pressure of each heat source in real time. The aforementioned multi-source complementary integrated hot air control device 200 is set in the PLC controller in the form of a control program. The actuator is connected to the PLC controller and may include an electric regulating valve, a variable frequency fan, a variable frequency water pump, etc., used to adjust the input ratio and heat exchange path of each waste heat source according to the adjustment instructions issued by the PLC controller. In other embodiments, a DCS (Distributed Control System) can also be used to replace the PLC for control. In addition, the aforementioned waste heat recovery module, heat energy enhancement module, hot air output module and intelligent control module can be integrated into an integrated cabinet or container structure to form a compact integrated multi-source complementary hot air station, which reduces the footprint by more than 40% compared with the traditional distributed solution, is easy to install, can be deployed quickly, and has an investment payback period of less than 2 years.

[0056] In one embodiment, the outlet water temperature of the air compressor waste heat recovery unit is 80℃~95℃, the temperature of the condensate recovered by the steam condensate waste heat recovery unit is 90℃~100℃, the temperature of the exhaust gas recovered by the spray drying tower exhaust gas waste heat recovery unit is 75℃~110℃, the industrial high-temperature heat pump unit is used to upgrade the low-grade waste heat of 50℃~100℃ to the medium-grade heat energy of 120℃~150℃, and the hot air output module also includes an auxiliary heater for supplementing the heat of fresh air so that the temperature of the output hot air is not lower than 150℃.

[0057] In this embodiment, the aforementioned temperature ranges are matched with the grade characteristics of each waste heat source. Specifically, the outlet water temperature of the air compressor waste heat recovery unit is 80℃~95℃, which corresponds to the typical range of the aforementioned first outlet water temperature T1; the temperature of the condensate recovered by the steam condensate waste heat recovery unit is 90℃~100℃, corresponding to the typical range of the aforementioned second outlet water temperature T2; and the temperature of the exhaust gas recovered by the spray drying tower exhaust gas waste heat recovery unit is 75℃~110℃. The temperatures of the aforementioned waste heat are all below 150℃, belonging to low-grade waste heat, which is difficult to directly meet the spray drying process's requirement for hot air above 150℃. However, the industrial high-temperature heat pump unit can enhance the low-grade waste heat of 50℃~100℃ to a medium-temperature heat energy of 120℃~150℃, which can then be used to effectively heat fresh air.

[0058] The auxiliary heater is used to supplement the heat of fresh air, serving as a supplementary heat source when waste heat is insufficient. For example, when the heat provided by each waste heat source is insufficient, and the condenser outlet temperature of the heat pump unit is still more than 10°C lower than the target temperature after full-load operation, the auxiliary heater is activated to supplement the heat of fresh air, ensuring that the temperature of the output hot air is not lower than 150°C. Since the auxiliary heater is only activated when waste heat is insufficient, the system can generate hot air using waste heat in most operating conditions, avoiding the high energy consumption and high carbon emissions caused by long-term reliance on electric heating or gas supplementary heating. Thus, it can continuously and stably output high-temperature hot air that meets the requirements of spray drying and flash drying processes under various operating conditions.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0060] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for controlling multi-source complementary integrated hot air, characterized in that, include: Real-time operating parameters of each waste heat source and the target temperature of the hot air in the multi-source complementary integrated hot air station are collected and summarized to obtain the operating dataset. The real-time operating parameters in the running dataset are compared with preset operating conditions to identify the current operating condition type and obtain the operating condition identification result. Based on the operating condition identification result, a strategy corresponding to the current operating condition type is matched from a variety of preset heat source allocation strategies and determined as the target heat source allocation strategy. Based on the target heat source allocation strategy, the input ratio and heat exchange path of each waste heat source are adjusted, and the fresh air is heated step by step to obtain output hot air. Monitor the actual outlet temperature of the output hot air, and adjust the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

2. The control method for multi-source complementary integrated hot air according to claim 1, characterized in that, The real-time operating parameters of each waste heat source in the multi-source complementary integrated hot air station and the target temperature of the hot air are collected and summarized to obtain an operating dataset, including: The following data were collected: the first outlet water temperature of the air compressor waste heat recovery unit, the second outlet water temperature of the steam condensate waste heat recovery unit, the exhaust temperature and relative humidity of the spray drying tower tail gas, the fresh air temperature, the target temperature of the hot air, the inlet temperature of the heat pump unit evaporator, and the outlet temperature of the condenser. All collected parameters are validated and outliers are removed, and the resulting dataset is compiled.

3. The control method for multi-source complementary integrated hot air according to claim 2, characterized in that, The step of comparing each of the real-time operating parameters in the running dataset with preset operating conditions to identify the current operating condition type and obtain the operating condition identification result includes: Extract the first outlet water temperature, the second outlet water temperature, the exhaust air temperature, and the relative humidity from the running dataset, respectively; When the first outlet water temperature is not lower than the first preset temperature and the second outlet water temperature is not lower than the second preset temperature, it is determined to be a high-grade heat source sufficient working condition. When the first outlet water temperature is lower than the first preset temperature or the second outlet water temperature is lower than the third preset temperature, it is determined to be a heat source insufficient condition. If the exhaust temperature is not lower than the first preset temperature and the relative humidity is not lower than the preset percentage, then the latent heat of the exhaust gas is determined to be usable. The working condition types and corresponding judgment times obtained from each judgment are summarized and recorded to generate working condition identification results.

4. The control method for multi-source complementary integrated hot air according to claim 3, characterized in that, The step of matching the strategy corresponding to the current operating condition type from a preset variety of heat source allocation strategies based on the operating condition identification result, and determining it as the target heat source allocation strategy, includes: The working condition identification results are analyzed to extract the working condition type determined at the current moment and obtain the strategy matching conditions; If the strategy matching condition is that the high-grade heat source is sufficient, then the first strategy is to prioritize direct heating of the waste heat of the generated steam condensate. If the strategy matching condition is the insufficient heat source condition, then a second strategy is generated to simultaneously activate the waste heat from the air compressor and the waste heat from the steam condensate, and the heat pump unit is at full load. If the strategy matching conditions are superimposed with the operating condition containing the latent heat of exhaust gas, then the third strategy of preheating fresh air with exhaust gas is superimposed. The first, second, and third strategies are combined according to priority and the execution parameters are configured to determine the target heat source allocation strategy.

5. The control method for multi-source complementary integrated hot air according to claim 4, characterized in that, The step of adjusting the input ratio and heat exchange path of each waste heat source based on the target heat source allocation strategy, and heating the fresh air step by step to obtain output hot air, includes: An adjustment command is generated based on the target heat source allocation strategy; wherein the adjustment command can adjust the electric regulating valve, the variable frequency fan, and the variable frequency water pump; In response to the adjustment command, the flow rate and input ratio of the medium corresponding to the waste heat source are adjusted, and the input low-grade waste heat is raised to the preset temperature range by the heat pump unit to obtain medium-temperature heat energy. Fresh air is sequentially sent through the exhaust gas preheater and the condenser of the heat pump unit, and heated step by step using the medium-temperature thermal energy. The heated fresh air is then sent to the hot air buffer tank for temporary storage, and finally output as hot air through the hot air buffer tank.

6. The control method for multi-source complementary integrated hot air according to claim 5, characterized in that, The process of monitoring the actual outlet temperature of the output hot air and adjusting the heat source input based on the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air includes: The actual outlet temperature of the output hot air in the hot air buffer tank is collected according to a preset adjustment cycle; The temperature deviation is obtained by subtracting the target temperature from the actual outlet temperature. When the temperature deviation is greater than the fourth preset temperature, the load of the heat pump unit is reduced or the flow rate of the medium input to the waste heat source is reduced. When the temperature deviation is less than the fifth preset temperature, increase the load of the heat pump unit or increase the flow rate of the medium input to the waste heat source; Repeat the above adjustments until the absolute value of the temperature deviation is within the preset value, and obtain the corrected output hot air.

7. The control method for multi-source complementary integrated hot air according to claim 6, characterized in that, Also includes: During the output of the corrected hot air, the operating status of each waste heat source recovery unit is periodically detected; The operating states are compared with the recorded fault criteria to identify the waste heat source recovery unit that has malfunctioned, and the faulty waste heat source is obtained. The recovery unit corresponding to the faulty waste heat source is disconnected, and the corresponding heat load is redistributed to the remaining waste heat sources. If the available heat from the remaining waste heat sources is still insufficient after redistribution, switch to the auxiliary heating mode supplied by the auxiliary heater, and update the target heat source allocation strategy simultaneously.

8. A control device for multi-source complementary integrated hot air, characterized in that, include: The data acquisition module is used to collect the real-time operating parameters of each waste heat source in the multi-source complementary integrated hot air station and the target temperature of the hot air, and summarize them to obtain the operating dataset. The working condition identification module is used to compare each of the real-time operating parameters in the running dataset with preset working condition conditions in order to identify the current working condition type and obtain the working condition identification result. The strategy determination module is used to match the strategy corresponding to the current working condition type from a variety of preset heat source allocation strategies based on the working condition identification results, and determine it as the target heat source allocation strategy. The heating control module is used to adjust the input ratio and heat exchange path of each of the waste heat sources based on the target heat source allocation strategy, and to heat the fresh air step by step to obtain output hot air. The dynamic adjustment module is used to monitor the actual outlet temperature of the output hot air and adjust the heat source input according to the deviation between the actual outlet temperature and the target temperature to obtain the corrected output hot air.

9. A control system for multi-source complementary integrated hot air, characterized in that, The control device for multi-source complementary integrated hot air as described in claim 8 further includes: The waste heat recovery module includes an air compressor waste heat recovery unit, a steam condensate waste heat recovery unit, and a spray drying tower exhaust gas waste heat recovery unit. The heat energy enhancement module includes an industrial high-temperature heat pump unit. The heat medium outlets of the air compressor waste heat recovery unit and the steam condensate waste heat recovery unit are connected in parallel and then connected to the evaporator inlet of the industrial high-temperature heat pump unit. The hot air output module includes a fresh air preheater and a hot air buffer tank. The hot air outlet of the waste heat recovery unit of the spray drying tower tail gas and the condenser outlet of the industrial high temperature heat pump unit are respectively connected to the first-stage preheating inlet and the second-stage preheating inlet of the fresh air preheater. The hot air outlet of the fresh air preheater outputs the hot air through the hot air buffer tank. An intelligent control module, comprising a PLC controller and an actuator, wherein the control device is disposed within the PLC controller and the PLC controller is connected to the actuator.

10. The control system for multi-source complementary integrated hot air according to claim 9, characterized in that, The outlet water temperature of the air compressor waste heat recovery unit is 80℃~95℃, the temperature of the condensate recovered by the steam condensate waste heat recovery unit is 90℃~100℃, the temperature of the exhaust gas recovered by the spray drying tower exhaust gas waste heat recovery unit is 75℃~110℃, the industrial high-temperature heat pump unit is used to upgrade the low-grade waste heat of 50℃~100℃ to the medium-grade heat energy of 120℃~150℃, and the hot air output module also includes an auxiliary heater for supplementing the heat of fresh air so that the temperature of the output hot air is not lower than 150℃.

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