Extremely low temperature heat energy recycling system and method based on advanced thermodynamic cycle

Abstract

The invention relates to the technical field of advanced thermodynamic circulation, in particular to an ultra-low-temperature heat energy recycling system and method based on advanced thermodynamic circulation. The method comprises the steps that a heat source guide and heat absorption unit preprocesses a low-temperature heat source and transmits heat data to a mixed working medium through a heat exchange module; the heat energy conversion and working medium compression unit receives the heat data and performs heat data conversion and working medium compression; the heat recovery and heat release unit reduces the temperature of a working medium through constant-pressure heat exchange and transmits heat data to Rankine cycle to do work outwards; and the working medium expansion and compression energy recovery refrigeration unit performs adiabatic expansion on the high-pressure and low-temperature working medium to further reduce the temperature and pressure of the working medium so as to provide cooling energy for the system. By adopting advanced thermodynamic cycle, especially an efficient energy conversion mechanism in an extremely low temperature range, waste low-temperature heat energy can be recycled and utilized to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of advanced thermodynamic cycles, and more specifically, to a cryogenic thermal energy recovery and utilization system and method based on an advanced thermodynamic cycle. Background Art

[0002] Due to the low energy density and high utilization cost of low-temperature thermal energy, early traditional energy conversion technologies regarded most of the gaseous thermal energy below 150°C and liquid thermal energy below 90°C as waste energy, such as kiln exhaust gas, power plant boiler flue gas, and industrial hot wastewater. Moreover, a large amount of cooling medium and cooling energy, such as circulating water, refrigerant, and refrigeration equipment, are required for the exchange and discharge of these energies during production, which not only causes energy waste but also consumes some energy, and this part of the energy accounts for about one-third or more of the total energy consumption of the factory; As of now, most research institutions claim to have achieved many results in the application fields of hot air as low as 90°C and hot water as low as 60°C, such as ORC organic working fluid low-temperature waste heat power generation, etc. Taking hot air utilization as an example, according to the second law of thermodynamics, assuming that the temperature of the primary heat source is 1050°C and the exhaust gas temperature after the first utilization is 150°C, the efficiency limit of the first utilization is 68.1%. After the secondary heat source at 150°C is utilized, the secondary exhaust gas temperature is 90°C, and the efficiency limit of the secondary utilization is 14.2%. If a third utilization is carried out, the utilization efficiency will be even lower, thus losing the utilization value. Therefore, providing a cryogenic thermal energy recovery and utilization system and method based on an advanced thermodynamic cycle is an important achievement in improving energy utilization efficiency and reducing process carbon emissions. Summary of the Invention

[0003] The purpose of the present invention is to provide a cryogenic thermal energy recovery and utilization system and method based on an advanced thermodynamic cycle to solve the problems of low current energy utilization efficiency, insufficient waste heat recovery, and high system carbon emissions proposed in the above background art.

[0004] To achieve the above object, on the one hand, the present invention aims to provide a cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle, including:

[0005] A heat source guiding and heat absorption unit, which pre-treats the low-temperature heat source and transmits heat data to the working fluid through a heat exchange module;

[0006] A thermal energy conversion and working fluid compression unit, which receives the heat data for heat data conversion and working fluid compression;

[0007] A heat recovery and heat release unit, which combines the Rankine cycle to transfer heat data and do external work;

[0008] The working fluid expansion pressure energy recovery module adiabatically expands the high-pressure and low-temperature working fluid to further reduce the temperature and pressure of the working fluid and provide cooling energy to the system.

[0009] The adiabatic expansion pressure energy recovery unit adiabatically expands the low-boiling-point working fluid, expanding the high-pressure, low-temperature, and low-boiling-point working fluid to low temperature and low pressure, and converting the pressure energy into cooling energy.

[0010] The working fluid mixing and pressurization unit mixes working fluids in different states and pressurizes the mixed working fluid.

[0011] The monitoring and control unit, through intelligent optimization and coordinated control, real-time predicts, adjusts, and optimizes each process of the thermal energy recovery system, and introduces the viscosity correction factor and the friction factor affected by the deposits on the inner surface of the pipeline into the intelligent optimization process for further optimization.

[0012] As a further improvement of this technical solution, the heat source guiding and heat absorption unit includes a heat source pretreatment module and a constant-pressure heat absorption module.

[0013] Among them, the heat source pretreatment module collects the low-temperature heat source and pre-treats the low-temperature heat source.

[0014] The constant-pressure heat absorption module transfers the heat of the low-temperature heat source to the mixed organic working fluid through a heat exchange module.

[0015] As a further improvement of this technical solution, the thermal energy conversion and working fluid compression unit includes a throttling and flashing module and an adiabatic compression module.

[0016] Among them, the throttling and flashing module reduces the temperature and pressure of the mixed organic working fluid through isentropic throttling, and transfers the thermal energy absorbed by the mixed organic working fluid to the low-boiling-point gas-phase working fluid.

[0017] The adiabatic compression module pressurizes the low-boiling-point gas-phase working fluid to increase the temperature and pressure of the low-boiling-point gas-phase working fluid.

[0018] As a further improvement of this technical solution, the heat recovery and heat release unit combines the Rankine cycle to transfer heat data, including a constant-pressure heat exchange and an additional Rankine cycle system.

[0019] Among them, the heat recovery and heat release unit includes that the low-boiling-point working fluid transfers heat data to the external Rankine cycle working fluid through partial condensation in the constant-pressure heat exchange module.

[0020] The heat recovery and heat release unit includes that the constant-pressure heat exchange reduces the temperature of the working fluid and transfers the heat data to the Rankine cycle working fluid in the constant-pressure heat exchange module.

[0021] The heat recovery and heat release unit includes using an additional Rankine cycle working fluid to do external work;

[0022] As a further improvement of this technical solution, the working fluid expansion pressure energy recovery module includes an adiabatic expansion process of a low-boiling-point working fluid;

[0023] The adiabatic expansion process of the low-boiling-point working fluid expands the high-pressure, low-temperature, low-boiling-point working fluid after transferring heat data to the heat recovery unit to low temperature and low pressure, converting pressure energy into cooling energy;

[0024] As a further improvement of this technical solution, the working fluid mixing and boosting unit includes a constant-pressure mixing module and an isentropic boosting module;

[0025] Among them, the constant-pressure mixing module mixes the throttled liquid-phase working fluid and the expanded gas-phase working fluid in a constant-pressure ratio;

[0026] The trace low-boiling-point gas-phase working fluid generated after the constant-pressure mixing enters the throttling flash evaporation module through an attached bypass pipeline for recovery;

[0027] The isentropic boosting module boosts the mixed working fluid through the working fluid pump module and sends the boosted mixed working fluid into the heat exchange module to continue heat exchange, completing an advanced thermodynamic cycle.

[0028] As a further improvement of this technical solution, the monitoring and control unit includes an intelligent optimization unit and a coordination and control unit;

[0029] Among them, the intelligent optimization unit includes a state prediction module, an efficiency optimization module, and a feedback control module;

[0030] The state prediction module, based on the real-time changes of the heat source and using a thermodynamic model, predicts the phase change of the mixed organic working fluid during the constant-pressure heat absorption process; predicts in real time the phase change of the working fluid in the throttling flash evaporation module to determine the evaporation amount of the low-boiling-point component; and predicts the thermodynamic properties of the working fluid through a regression model to adjust the heat exchange process and the boosting strategy;

[0031] The efficiency optimization module, through analysis, adjusts the opening degree of the throttling module, and introduces the viscosity correction factor and the friction factor affected by the deposits on the inner surface of the pipeline into the analysis formula for optimization to give priority to the evaporation of the low-boiling-point component; adjusts the boosting ratio and load of the adiabatic compression module and the adiabatic expansion module through a genetic algorithm; and adjusts the working parameters of the heat exchanger according to the real-time working fluid flow rate and temperature;

[0032] The feedback control module, by monitoring the ratio of the working fluid in the mixing tank and the pressure of the boosting pump in the working fluid mixing and boosting unit, adjusts the operating state of the pump module in real time;

[0033] Among them, the coordination and control unit includes a flash and compression linkage control module, an expansion and mixing synchronization optimization module, and a waste heat recovery process coordination module;

[0034] The flash and compression linkage control module, based on the prediction of the working fluid phase change, monitors in real time the mass fraction of the gaseous working fluid in the flash module, and dynamically adjusts the operating state of the adiabatic compression module according to the mass fraction based on the model predictive control algorithm;

[0035] The waste heat recovery process coordination module monitors the heat transfer efficiency of each heat exchange module based on the feedback control module, and adjusts the flow rate and temperature of the cooling medium.

[0036] The expansion and mixing synchronization optimization module monitors the power, temperature, and pressure of the working fluid output by the adiabatic expansion module based on the efficiency optimization module, and synchronously adjusts with the working fluid ratio in the mixing tank;

[0037] The waste heat recovery process coordination module monitors the heat transfer efficiency of each heat exchange module based on the feedback control module, and adjusts the flow rate and temperature of the cooling medium.

[0038] As a further improvement of this technical solution, the analysis is as follows:

[0039]

[0040] Among them, E sf represents the change of the working fluid; m sf represents the mass flow rate of the working fluid; C sf represents the average specific heat capacity of the working fluid; T sf represents the temperature of the working fluid after throttling; T0 represents the ambient temperature;

[0041] The viscosity of the fluid affects the flow resistance and heat transfer characteristics. According to the viscosity, flow velocity, and Reynolds number of the fluid, a viscosity correction factor α u is established:

[0042]

[0043] Among them, β represents the intrinsic viscosity of the fluid; k represents a constant correction factor (adjusted according to the type of fluid and flow conditions); v represents the flow velocity; d represents the inner diameter of the pipe; Re represents the Reynolds number;

[0044] Sediments cause an increase in the surface roughness of the pipe. The roughness of the inner surface of the pipe is corrected, and the thickness of the sediment is expressed as the thickness of the sediment layer between the fluid and the pipe surface:

[0045] θ eff = θ or + γ s ;

[0046] Among them, θ eff represents the effective surface roughness considering the sediment; θ or represents the original roughness of the pipeline without sediment; γ s represents the sediment thickness;

[0047] The sediment increases the roughness of the inner surface of the pipeline, and the friction factor f ro is corrected according to the effective roughness:

[0048]

[0049] The viscosity correction factor α u and the friction factor f affected by the sediment on the inner surface of the pipeline ro are introduced into the analysis formula for optimization:

[0050]

[0051] Among them, E sf1 represents the change of the working medium after optimization.

[0052] As a further improvement of this technical solution, the operation state of the adiabatic compression module is dynamically adjusted according to the mass fraction based on the model predictive control algorithm, including the following steps:

[0053] S3.1. Monitor the mass fraction of the gas-phase working medium in the flash module in real time, and transmit the mass fraction as a feedback signal to the control system;

[0054] S3.2. Determine the target gas-phase mass fraction;

[0055] S3.3. Based on the current gas-phase mass fraction and the compressor pressure, predict the future state through the model predictive control algorithm, establish an optimization problem formula to optimize the control input, and introduce the gas-liquid separation efficiency parameter into the optimization problem formula of the predictive control algorithm for optimization;

[0056] S3.4. Dynamically adjust the operation state of the compressor according to the optimization result of the model predictive control algorithm.

[0057] As a further improvement of this technical solution, in S3.3, the optimization problem formula is:

[0058]

[0059] Among them, r(t) represents the control input variable; w ga (i) represents the actual gas-phase mass fraction at the i-th step; w gat (i) represents the target gas-phase mass fraction at the i-th step; Pco (i) represents the actual output pressure of the adiabatic compression module at the i-th step; P cot (i) represents the target output pressure of the adiabatic compression module at the i-th step; Q represents the weighted matrix of the output pressure error of the adiabatic compression module; R represents the weighted matrix of the output pressure error of the adiabatic compression module; i represents the index traversing the prediction horizon; t represents time; N represents the length of the prediction horizon;

[0060] Considering the influence of the gas-liquid separation efficiency in the flash module on the mass of the input gas of the compressor, a gas-liquid separation efficiency parameter is introduced into the optimization problem formula of the predictive control algorithm for optimization:

[0061] Taking the gas-liquid separation efficiency d(t) as another control variable and incorporating it into the optimization problem formula to penalize the negative impact brought by low separation efficiency:

[0062]

[0063] Among them, d1(t) represents the target gas-liquid separation efficiency; represents the penalty coefficient; A represents the weighted matrix of the separation efficiency error.

[0064] On the other hand, the present invention provides a method for recycling cryogenic thermal energy based on an advanced thermodynamic cycle, which is used for the above-mentioned cryogenic thermal energy recycling system based on an advanced thermodynamic cycle, and includes the following steps:

[0065] S4.1. Pretreat the low-temperature heat source and transmit the heat data to the working fluid through the heat exchange module;

[0066] S4.2. Receive the heat data for heat data conversion and compression of the working fluid;

[0067] S4.3. Combine the Rankine cycle to transfer thermal energy to do external work;

[0068] S4.4. Convert the pressure energy into cooling energy through the adiabatic expansion pressure energy recovery module;

[0069] S4.5. Mix the working fluids in different states and boost the mixed working fluid;

[0070] S4.6. Through intelligent optimization and coordinated control, real-time predict, adjust and optimize each process of the thermal energy recovery system.

[0071] Compared with the prior art, the beneficial effects of the present invention:

[0072] 1. In the cryogenic thermal energy recovery and utilization system and method based on advanced thermodynamic cycles, by adopting advanced thermodynamic cycles, especially the efficient energy conversion mechanism in the extremely low temperature range, the waste cryogenic thermal energy can be recovered and utilized to the maximum extent. In refrigeration engineering, a part of the heat that needs to be removed is recovered and used for work, replacing part of the externally supplied power, minimizing the externally supplied power, and reducing the total discharged energy and cooling water consumption to the minimum, thus achieving the purpose of energy conservation and emission reduction and further lowering the limit of cryogenic thermal energy utilization in refrigeration engineering. The COP of the cryogenic thermal energy utilization refrigeration engineering using a mixed refrigerant thermodynamic cycle can reach above 7.0.

[0073] 2. In the cryogenic thermal energy recovery and utilization system and method based on advanced thermodynamic cycles, by applying advanced thermodynamic cycle technology in the process of recovering low-temperature waste heat, the energy consumption relying on traditional fuels can be reduced, thereby reducing the emissions of greenhouse gases and harmful pollutants. This not only helps to promote the green transformation of the energy structure but also is of great significance for alleviating global climate change and improving air quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is the overall process block diagram of the present invention;

[0075] Figure 2 It is the schematic diagram of the advanced thermodynamic cycle of the present invention;

[0076] The meanings of each label in the figure are as follows:

[0077] 1. Heat source guiding and heat absorption unit; 11. Heat source pretreatment module; 12. Constant pressure heat absorption module; 2. Thermal energy conversion and refrigerant compression unit; 21. Throttling and flashing module; 22. Adiabatic compression module; 23. Refrigerant expansion pressure energy recovery module; 3. Heat recovery and heat release unit; 4. Refrigerant mixing and boosting unit; 41. Constant pressure mixing module; 42. Isentropic boosting module; 5. Monitoring and control unit; 51. Intelligent optimization unit; 511. State prediction module; 512. Efficiency optimization module; 513. Feedback control module; 52. Coordination and control unit; 521. Flashing and compression linkage control module; 522. Expansion and mixing synchronous optimization module; 523. Waste heat recovery process coordination module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0078] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0079] Example 1: Please refer to Figure 1 As shown, a cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle is provided, including:

[0080] The heat source guiding and heat absorption unit 1 pre-treats the low-temperature heat source and transmits the heat data to the working fluid through the heat exchange module (the transmission schematic diagram is as shown in Figure 2 shown);

[0081] In this embodiment, the heat source guiding and heat absorption unit 1 includes a heat source pre-treatment module 11 and a constant-pressure heat absorption module 12;

[0082] Among them, the heat source pre-treatment module 11 collects the low-temperature heat source and pre-treats the low-temperature heat source (waste heat, waste heat or environmental heat). The pre-treatment process includes adjusting the temperature and pressure of the heat source to ensure that the heat source meets the operation requirements when entering the subsequent heat exchanger. In this embodiment, the heat source pre-treatment module 11 uses a heat exchanger;

[0083] The constant-pressure heat absorption module 12 transmits the heat of the low-temperature heat source to the mixed organic working fluid through the heat exchange module (heat exchanger). In this embodiment, the mixed organic working fluid uses R600a / R245fa.

[0084] The thermal energy conversion and working fluid compression unit 2 receives the heat data for the conversion of the heat data and the compression of the working fluid to ensure the efficient conversion and output of energy;

[0085] In this embodiment, the thermal energy conversion and working fluid compression unit 2 includes a throttling and flashing module 21, an adiabatic compression module 22 and a working fluid expansion pressure energy recovery module 23;

[0086] Among them, the throttling and flashing module 21 reduces the temperature and pressure of the mixed organic working fluid through isentropic throttling, and the low-boiling organic working fluid evaporates preferentially, so that the thermal energy absorbed by the mixed organic working fluid is transferred to the low-boiling gas-phase working fluid. In this embodiment, the throttling and flashing module 21 includes a throttling device and a flash tank;

[0087] The adiabatic compression module 22 pressurizes the low-boiling-point gaseous working fluid, increasing the temperature and pressure of the low-boiling-point gaseous working fluid to prepare for the subsequent heat release process (pressurizing compressor). The mixed working fluid enters the throttling device at a relatively high temperature and pressure. At this time, the mixed working fluid may be in a liquid phase or a gas-liquid two-phase state. The pressure of the mixed working fluid is reduced to the target pressure through the throttling module (throttling device). This process is idealized as an isentropic process. Due to the decrease in temperature and pressure, the low-boiling-point component (R600a) in the mixed working fluid evaporates preferentially, forming a gas-liquid two-phase mixture, while the high-boiling-point component (R245fa) mainly remains in the liquid phase. The gas-liquid two-phase mixture is transported into the flash evaporation module (flash tank), where gas-liquid separation is further achieved. The gas phase is collected and sent to the compressor for subsequent processing, while the liquid phase is sent to the working fluid mixing and pressurizing unit for recirculation. In this embodiment, the adiabatic compression module 22 uses a pressurizing compressor to transfer heat data to the heat recovery and heat release unit 3;

[0088] The working fluid expansion pressure energy recovery module 23 adiabatically expands the high-pressure and low-temperature working fluid to further reduce the temperature and pressure of the working fluid and provide cooling energy to the system. An expander is used in this process to convert pressure energy into cooling or mechanical energy. External work is done through a two-phase screw expander to reduce the temperature and pressure of the saturated working fluid; the working fluid expansion pressure energy recovery module 23 includes an adiabatic expansion process of the low-boiling-point working fluid; the adiabatic expansion process of the low-boiling-point working fluid expands the high-pressure, low-temperature, and low-boiling-point working fluid after transferring heat data to the heat recovery unit to low temperature and low pressure, converting pressure energy into cooling energy.

[0089] The heat recovery and heat release unit 3 includes a constant-pressure heat exchange and an additional Rankine cycle system;

[0090] Among them, the heat recovery and heat release unit 3 includes that the low-boiling-point working fluid transfers heat data to the external Rankine cycle working fluid through partial condensation in the constant-pressure heat exchange module;

[0091] The heat recovery and heat release unit 3 includes that the temperature of the working fluid is reduced by constant-pressure heat exchange in the constant-pressure heat exchange module and the heat data is transferred to the Rankine cycle working fluid;

[0092] The heat recovery and heat release unit 3 includes using the additional Rankine cycle working fluid to do external work;

[0093] In this embodiment, the heat recovery and heat release unit 3 transports the working fluid from the outlet of the adiabatic compression module 22 to the heat release module. At this time, the working fluid is usually in a high-temperature and high-pressure state. In this embodiment, the heat release module uses a heat exchanger;

[0094] In the exothermic module, the working fluid exchanges heat at a constant pressure with the external Rankine cycle working fluid (such as external organic working fluid) through the heat exchange module (heat exchanger). Heat is transferred from the working fluid to the Rankine cycle working fluid. The exothermic process usually reduces the temperature and pressure of the working fluid, and the state of the working fluid gradually changes from a high-temperature gas (or gas-liquid mixture) to a low-temperature liquid (or low-saturated gas).

[0095] In the heat exchanger, the working fluid usually partially condenses and releases latent heat. The released heat is transferred to the Rankine cycle working fluid through the heat exchange module for heating or doing work, improving the energy utilization efficiency of the system. In this embodiment, the heat exchange module uses a heat exchanger.

[0096] The adiabatic expansion module 23 expands the high-pressure and low-temperature working fluid to low temperature and low pressure.

[0097] In this embodiment, the adiabatic expansion module uses a screw expander to convert pressure energy into cooling or mechanical energy, and the two-phase screw expander does work externally to reduce the temperature and pressure of the saturated working fluid.

[0098] The expansion process is a two-phase expansion. In the expander, the pressure of the working fluid drops to balance with the pressure of the throttling flash evaporation module, and the temperature of the working fluid drops below the flash evaporation temperature of the mixed working fluid.

[0099] The working fluid mixing and boosting unit 4 mixes working fluids in different states and boosts the mixed working fluid to ensure the continuous operation of the system.

[0100] In this embodiment, the working fluid mixing and boosting unit 4 includes a constant-pressure mixing module 41 and an isentropic boosting module 42.

[0101] Among them, the constant-pressure mixing module 41 mixes the high-boiling-point working fluid after throttling flash evaporation and the low-boiling-point working fluid after adiabatic expansion at a constant pressure in proportion.

[0102] The isentropic boosting module 42 boosts the mixed working fluid through the working fluid pump module and sends the boosted mixed working fluid into the heat source guiding and heat absorption unit 1 to continue heat exchange, completing the advanced thermodynamic cycle. In this embodiment, the isentropic boosting module uses a working fluid pump.

[0103] The monitoring and control unit 5, through intelligent optimization and coordinated control, real-time predicts, adjusts, and optimizes each process (phase change, throttling flash evaporation, compression and expansion) of the heat energy recovery system to ensure efficient energy conversion and heat transfer, while maximizing the overall performance of the system and the energy utilization efficiency, and introducing the viscosity correction factor and the friction factor affected by the deposits on the inner surface of the pipeline into the intelligent optimization process for further optimization.

[0104] In this embodiment, the monitoring and control unit 5 includes an intelligent optimization unit 51 and a coordination and control unit 52.

[0105] Among them, the intelligent optimization unit 51 includes a state prediction module 511, an efficiency optimization module 512, and a feedback control module 513;

[0106] The state prediction module 511 predicts the phase change of the mixed organic working fluid during the constant-pressure heat absorption process based on the real-time changes of the heat source (waste heat source temperature, pressure, etc.) according to the thermodynamic model. Through the prediction model, the system can optimize the regulation of the heat source to ensure that heat is efficiently transferred to the working fluid and improve the heat transfer efficiency; predict the phase change of the working fluid in the throttling flash evaporation module 21 in real time, determine the evaporation amount of the low-boiling component, so as to optimize the throttle valve opening to ensure the maximization of the proportion of the gaseous working fluid and reduce the energy loss in the subsequent compression and expansion processes; and predict the thermodynamic properties (temperature, pressure, enthalpy value) of the working fluid through the regression model, adjust the heat exchange process and the pressurization strategy to ensure the efficient recovery of heat and the optimal flow state of the working fluid;

[0107] The efficiency optimization module 512 passes through Analysis, adjust the opening of the throttling module (throttling device), and introduce the viscosity correction factor and the friction factor affected by the deposits on the inner surface of the pipeline into The analysis formula is optimized to give priority to the evaporation of the low-boiling component, avoid wasting heat by the high-boiling component, reduce unnecessary energy consumption through the optimization of the throttling flash evaporation process, thereby improving the thermal energy conversion efficiency of the overall system; adjust the pressure ratio and load of the adiabatic compression module 22 and the adiabatic expansion module 23 through the genetic algorithm to make the energy conversion process of the system more efficient, avoid excessive power consumption caused by over-compression or over-expansion, and maximize the energy recovery of the compression and expansion processes; and adjust the working parameters of the heat exchanger, such as the heat transfer area, flow rate, etc., according to the real-time working fluid flow rate and temperature to ensure that heat is efficiently transferred from the working fluid to the external cooling medium;

[0108] Furthermore, The analysis is as follows:

[0109]

[0110] Among them, E sf represents the change of the working fluid; m sf represents the mass flow rate of the working fluid; C sf represents the average specific heat capacity of the working fluid; T sf represents the temperature of the working fluid after throttling; T0 represents the ambient temperature;

[0111] The viscosity of the fluid affects the flow resistance and heat transfer characteristics. In the throttling flash evaporation and heat exchange processes, the influence of viscosity on the flow will affect the efficiency of the heat conduction process, and further affect the thermal energy change. The viscosity of the fluid is introduced as a correction factor into In the analysis formula, the viscosity of the fluid usually affects the thermal conductivity of the fluid, the flow state (laminar flow, turbulent flow), and the frictional loss between the fluid and the pipe surface;

[0112] The viscosity of the fluid affects the flow resistance and heat transfer characteristics. According to the viscosity of the fluid, the flow velocity, and the Reynolds number, a viscosity correction factor α is established. u Generally speaking, an increase in viscosity will lead to an increase in turbulent losses in the flow and a decrease in heat transfer efficiency. Therefore, the formula for heat energy change can be corrected according to the actual flow state of the fluid:

[0113]

[0114] where β represents the inherent viscosity of the fluid; k represents a constant correction factor (adjusted according to the type of fluid and flow conditions); v represents the flow velocity; d represents the inner diameter of the pipe; Re represents the Reynolds number;

[0115] Sediments cause an increase in the surface roughness of the pipe. The roughness of the inner surface of the pipe is corrected. The thickness of the sediment is expressed as the thickness of the sediment layer between the fluid and the pipe surface (the sediment increases the roughness of the inner surface of the pipe, resulting in an increase in the friction between the fluid and the pipe wall. This frictional loss will reduce the overall efficiency of the system, especially in a heat energy recovery system, because higher frictional losses will cause more energy to be converted into heat and consumed, rather than being used for effective heat transfer. The accumulation of sediments may cause a change in the flow state of the fluid. For example, at a lower flow velocity, the flow may still remain in a laminar state, while at a higher flow velocity, turbulence may be induced. Since the rough surface affects the interaction between the fluid and the pipe wall, the sediment makes the flow more unstable, may change the Reynolds number of the flow, and lead to a transition in the flow state. This change will affect the flow resistance, turbulence generation, and heat transfer efficiency; the sediment inside the pipe increases the thermal resistance, especially during the heat exchange process. The sediment layer reduces the effective contact between the fluid and the pipe wall, reducing the heat transfer efficiency. As the thickness of the sediment increases, the conduction and convection processes of heat through the pipe wall are hindered, thus affecting the heat energy recovery effect):

[0116] θ eff = θ or + γ s ;

[0117] where θ eff represents the effective surface roughness considering the sediment; θ or represents the original roughness of the pipe without sediment; γ s represents the sediment thickness;

[0118] The sediment increases the roughness of the inner surface of the pipe, and the friction factor f roCorrection based on effective roughness (As sediment accumulates on the inner surface of the pipeline, the surface roughness increases, resulting in increased friction between the fluid and the pipe wall. During fluid flow, the rough surface of the pipe wall (sediments, scale, etc.) exerts a drag force on the fluid, thereby generating additional frictional resistance):

[0119]

[0120] Introduce the viscosity correction factor α u and the friction factor f affected by the sediment on the inner surface of the pipeline ro into Optimize in the analysis formula (Introducing the viscosity correction factor α u and the friction factor f affected by the sediment on the inner surface of the pipeline ro into the formula together can comprehensively consider the physical properties of the fluid (such as viscosity) and the structural changes of the system (such as pipeline surface roughness and sediment influence), thus comprehensively optimizing the calculation of the heat recovery process):

[0121]

[0122] where, E sf1 represents the change of the working medium after optimization change.

[0123] The feedback control module 513 monitors the proportion of the working medium in the mixing tank and the pressure of the booster pump in the working medium mixing and boosting unit 4 in real time, and adjusts the operating state of the pump module (regulating pump) in real time to ensure the best efficiency of the working medium flow and heat exchange;

[0124] wherein, the coordination and control unit 52 includes a flash and compression linkage control module 521, an expansion and mixing synchronous optimization module 522, and a waste heat recovery process coordination module 523;

[0125] The flash and compression linkage control module 521 monitors the mass fraction of the gaseous working medium in the flash module (flash tank) in real time based on the prediction of the working medium phase change, and dynamically adjusts the operating state of the adiabatic compression module 22 based on the mass fraction using the model predictive control algorithm. Through linkage control, it ensures that the compressor boost ratio meets the requirements of the subsequent links, avoiding energy loss or unnecessary power consumption caused by excessive or insufficient compression;

[0126] Among them, by monitoring the mass fraction of the gaseous working medium in real time and adjusting the operating parameters of the compressor accordingly, it is possible to ensure that the compression process is always carried out in an optimal state, avoid unnecessary energy consumption, and thus significantly improve the thermal energy conversion efficiency of the entire system; the model predictive control algorithm can quickly respond to changes in heat sources and operating conditions, and timely adjust the operating parameters of the compressor, such as speed, load, etc., enabling the system to more flexibly cope with different operating conditions and maintain an efficient operating state; dynamically adjusting the pressure ratio and load of the compressor can avoid energy waste caused by over-compression or expansion, maximize energy recovery during compression and expansion processes, and further improve energy utilization efficiency;

[0127] Dynamically adjust the operating state of the adiabatic compression module 22 based on the mass fraction using the model predictive control algorithm, including the following steps:

[0128] S3.1. Monitor the mass fraction of the gaseous working medium in the flash module (flash tank) in real time, and transmit the mass fraction as a feedback signal to the control system;

[0129] S3.2. Determine the target gaseous mass fraction;

[0130] S3.3. Based on the current gaseous mass fraction and compressor pressure, predict the future state through the model predictive control algorithm, establish an optimization problem formula to optimize the control input, and introduce the gas-liquid separation efficiency parameter into the optimization problem formula of the predictive control algorithm for optimization. The optimization goal is to make the gaseous mass fraction and the compressor output pressure as close as possible to the desired target values;

[0131] Furthermore, the optimization problem formula is:

[0132]

[0133] Among them, r(t) represents the control input variable, such as the speed or power of the adiabatic compression module 22; N represents the number of time steps considered by the optimization algorithm; wga(i) represents the actual gaseous mass fraction at the i-th step; wgat(i) represents the target gaseous mass fraction at the i-th step; P co (i) represents the actual output pressure of the adiabatic compression module 22 at the i-th step; P cot (i) represents the target output pressure of the adiabatic compression module 22 at the i-th step; Q represents the weighting matrix of the output pressure error of the adiabatic compression module 22; R represents the weighting matrix of the output pressure error of the adiabatic compression module 22; i represents the index traversing the prediction horizon; t represents time; N represents the length of the prediction horizon, which means that when the control system performs optimization calculations, it will predict the system behavior in the future for a period of time. During this period, the control input will be optimized to meet the predetermined goals and constraints;

[0134] Considering the influence of the gas-liquid separation efficiency in the flash module on the quality of the input gas to the compressor, a gas-liquid separation efficiency parameter is introduced into the optimization problem formula of the predictive control algorithm for optimization. (The core function of the flash module is to separate the mixed working fluid into gas and liquid at different temperatures and pressures. The effect of this process directly determines the mass flow rate of the gas-phase working fluid entering the compressor. Efficient gas-liquid separation can reduce the entrainment of the liquid-phase working fluid, thus ensuring that mainly gas-phase working fluid enters the compressor. When the gas-liquid separation efficiency is low, more liquid-phase working fluid will enter the compressor, which will cause the compressor to handle more incompressible liquid, increase the compression power consumption, and reduce the overall energy efficiency of the system. Therefore, incorporating the gas-liquid separation efficiency into the optimization algorithm can avoid the energy loss caused by low-efficiency separation):

[0135] The gas-liquid separation efficiency d(t) is incorporated as another control variable into the optimization problem formula to penalize the negative impact brought by low separation efficiency:

[0136]

[0137] where d1(t) represents the target gas-liquid separation efficiency; represents the penalty coefficient, which is used to weigh the importance of the gas-liquid separation efficiency error term; A represents the weighted matrix of the separation efficiency error;

[0138] For the gas-liquid separation efficiency d(t), a recurrence formula is designed. (The operation of the thermodynamic cycle system is time-varying, and the state of the working fluid changes with time. Especially during the heat energy recovery process, the gas-liquid separation efficiency is affected by variables such as the temperature, pressure, and mass flow rate of the fluid, and these variables themselves change with time and the system state. Therefore, using a recurrence formula can capture this time-variability; the recurrence formula helps to adjust the system parameters in real time. For example, by considering the change in the separation efficiency at the previous moment, the operating state of the flash module can be dynamically adjusted to maintain the stability and efficiency of the system. Through recurrence, the operation decision at the next moment can be based not only on the current input but also on past trends and states, which is crucial for real-time adjustment):

[0139]

[0140] where δ1 represents the inertia of the separation efficiency with respect to time; δ2 represents the influence of the gas flow rate on the separation efficiency; δ3 represents the influence of the temperature difference on the separation efficiency; mg(t) represents the gas flow rate at the t-th step; mt(t) represents the total flow rate (gas + liquid) at the t-th step; Te(t) represents the ambient temperature at the t-th step; T0 represents the reference temperature, which is the ambient temperature or the benchmark temperature under the system operating conditions.

[0141] S3.4. Dynamically adjust the operating state of the compressor (adjust the rotational speed, power, etc. of the compressor) according to the optimization results of the model predictive control algorithm to ensure the efficient operation of the system.

[0142] The expansion and mixing synchronous optimization module 522 monitors the power output by the adiabatic expansion module 23, the temperature and pressure of the working fluid, and synchronously adjusts with the proportion of the working fluid in the mixing tank. By ensuring that the power in the expansion process is consistent with the ratio of the mixed working fluid, the system can ensure the maximization of the constant-pressure mixing effect and effectively improve the heat energy recovery efficiency.

[0143] The waste heat recovery process coordination module 523 monitors the heat transfer efficiency of each heat exchange module (heat exchanger) based on the feedback control module 513. According to the real-time feedback, it adjusts the flow rate and temperature of the cooling medium to ensure that the heat exchanger works at the best efficiency, avoid overheating or overcooling of heat exchange, improve the heat energy transfer efficiency, and reduce heat waste.

[0144] Embodiment 2: Please refer to Figure 2 As shown, a cryogenic heat energy recovery and utilization system based on an advanced thermodynamic cycle is provided, including taking a data center refrigeration system with a power consumption of 100 kW as an example to illustrate the beneficial effects of the present invention:

[0145] In this embodiment, taking a data center refrigeration system with a power consumption of 100 kW as an example, a data center refrigeration model based on an advanced thermodynamic cycle is established, and the heat source temperature is about 45 - 60 ° (the temperature of the hot air in the computer room).

[0146] Assume: The total power consumption of the computing equipment is Nt = 100 Kw,

[0147] Then, the total heat transfer amount Qt = η1·x·η2·x·η3·Nt = 80 (Kw),

[0148] In the formula: Qt is the heat load of the computer equipment;

[0149] Nt is the total power consumption of the computing equipment (to simplify the problem, the auxiliary power consumption is not considered);

[0150] η1 is the simultaneous use factor;

[0151] η2 is the utilization factor;

[0152] η3 is the load working uniformity factor;

[0153] Generally, η1, η2, η3 take values between 0.6 and 0.8. Considering the redundancy of the refrigerating capacity, usually η1·η2·η3 takes the upper limit value of 0.8.

[0154] Therefore, the refrigerating capacity requirement of the system is 80 kW, that is, the heat transfer amount of the mixed working fluid is 80 kW;

[0155] Assume that for the ultra-low temperature heat energy recovery and utilization system of an advanced thermodynamic cycle, the mixed refrigerant is R600a / R245fa with a mixing ratio of 15:85. Then the specific heat capacity of the mixed refrigerant is 1.45 Kj / kg·K, the density of the gaseous refrigerant R600a is 1.19 m3 / kg, the temperature rise in the plate evaporator is 20 °C, the isentropic efficiency of the compressor is 0.8, the dryness of the working fluid in the two-phase flow expander is 0.3, and the isentropic efficiency is 0.75. Then:

[0156] In the plate heat exchanger, the flow rate of the mixed refrigerant should be: 9.91 t / h;

[0157] The mass flow rate of the gaseous phase after throttling and flashing is: 766 kg / h, which is also 644 m3 / h or 0.22 kg / s. The calculated power consumption of the compressor is: 766 x 88.2 = 67561 kj / h = 18.7 kW, and the actual power consumption is about 23.4 kW;

[0158] The output power of the R600a expander is: 766 x 233 = 178478 kj / h = 49.6 kW, and the actual output power is about 37.1 kW.

[0159] Also assume that for the auxiliary Rankine cycle, the working fluid is a single refrigerant R245fa, the dryness of the working fluid in the expander is 0.6, and the isentropic efficiency of the expander is 0.8, then

[0160] In the secondary plate heat exchanger, the flow rate of the working fluid is 503 kg / h;

[0161] The output power of the R245fa expander is: 503 x 38 = 19128 kj / h = 5.3 kW, and the actual power is about 4.25 kW.

[0162] Therefore, the externally supplied power Ns of the system should be: Ns = 23.4 - 37.1 - 4.25 = -17.95 kW.

[0163] The heat discharged from the system is: 88025 Kj / h;

[0164] The externally supplied cooling water volume of the system: 22 t / h;

[0165] Compared with the traditional refrigeration method:

[0166] The externally supplied power of the system is: 40 kW (PUE is calculated as 1.4);

[0167] The heat discharged from the system is: 360000 Kj / h;

[0168] The externally supplied cooling water volume of the system: 90 t / h;

[0169] Here, Ns is the actual externally supplied power: -17.95 (kW).

[0170] System PUE: PUE = 1 + (-17.95) / 100kW = 0.82;

[0171] Total of the system The efficiency is: 0.227 / 1.173 = 19.35%;

[0172] The coefficient of performance (COP) of the system is as high as 7.04.

[0173] The difference between Embodiment 2 and Embodiment 1 of the present invention is that Embodiment 1 introduces the advanced thermodynamic cycle method used in the cryogenic thermal energy recovery and utilization system based on the advanced thermodynamic cycle, and Embodiment 2 is a specific application example of the cryogenic thermal energy recovery and utilization system based on the advanced thermodynamic cycle.

[0174] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. An ultra-low temperature thermal energy recovery and utilization system based on an advanced thermodynamic cycle, characterized in that, Comprising: A heat source guiding and heat absorption unit (1), which pre-treats a low-temperature heat source and transmits heat data to a mixed organic working fluid through a heat exchange module; A thermal energy conversion and working fluid compression unit (2), which receives heat data for the conversion of heat data and the compression of the working fluid; A heat recovery and heat release unit (3), which reduces the temperature of the working fluid through constant-pressure heat exchange and transfers heat data to a Rankine cycle to do external work; The working fluid expansion pressure energy recovery module (23), which adiabatically expands the high-pressure and low-temperature working fluid to further reduce the temperature and pressure of the working fluid and provides cooling energy to the system; A working fluid mixing and boosting unit (4), which mixes working fluids in different states and boosts the mixed working fluid; A monitoring and control unit (5), which, through intelligent optimization and coordinated control, real-time predicts, adjusts, and optimizes each process of the heat energy recovery system, and introduces a viscosity correction factor and a friction factor affected by deposits on the inner surface of the pipeline into the intelligent optimization process for further optimization.

2. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 1, wherein: The heat source guiding and heat absorption unit (1) includes a heat source pre-treatment module (11) and a constant-pressure heat absorption module (12); Wherein, the heat source pre-treatment module (11) collects the low-temperature heat source and pre-treats the low-temperature heat source; The constant-pressure heat absorption module (12) transmits the heat of the low-temperature heat source to the mixed organic working fluid through a heat exchange module.

3. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 2, wherein: The thermal energy conversion and working fluid compression unit (2) includes a throttling flash evaporation module (21) and an adiabatic compression module (22); Wherein, the throttling flash evaporation module (21) reduces the temperature and pressure of the mixed organic working fluid through isentropic throttling, so that the thermal energy absorbed by the mixed organic working fluid is transferred to the low-boiling-point working fluid to promote the gasification of the low-boiling-point working fluid; The adiabatic compression module (22) boosts the pressure of the low-boiling-point gaseous working fluid, raises the temperature and pressure of the low-boiling-point gaseous working fluid, and transmits heat data to the heat recovery and heat release unit (3).

4. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 3, characterized in that: The heat recovery and heat release unit (3) includes a constant-pressure heat exchange and an additional Rankine cycle system; Wherein, the heat recovery and heat release unit (3) includes that in the constant-pressure heat exchange module, the low-boiling-point working fluid transfers heat data to the external Rankine cycle working fluid through partial condensation; The heat recovery and heat release unit (3) includes that in the constant-pressure heat exchange module, the temperature of the working fluid is reduced through constant-pressure heat exchange and the heat data is transferred to the Rankine cycle working fluid; The heat recovery and heat release unit (3) includes using an additional Rankine cycle working fluid to do external work.

5. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 4, characterized in that: The working fluid expansion pressure energy recovery module (23) includes an adiabatic expansion process of the low-boiling-point working fluid; The adiabatic expansion process of the low-boiling-point working fluid expands the high-pressure, low-temperature, and low-boiling-point working fluid after transferring heat data to the heat recovery unit to low temperature and low pressure, converting the pressure energy into cooling energy.

6. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 5, characterized in that: The working fluid mixing and boosting unit (4) includes a constant-pressure mixing module (41) and an isentropic boosting module (42); Among them, the constant-pressure mixing module (41) mixes the throttled low-temperature, low-pressure, high-boiling-point liquid-phase working medium with the expanded low-temperature, low-pressure two-phase low-boiling-point working medium at a constant pressure; The trace low-boiling-point gaseous working medium generated after the constant-pressure mixing enters the throttling and flashing module through an attached bypass pipeline for recovery; The isentropic pressurization module (42) pressurizes the mixed working medium through the working medium pump module and sends the pressurized mixed working medium into the heat exchange module to continue heat exchange, completing the advanced thermodynamic cycle.

7. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 6, characterized in that: The monitoring and control unit (5) includes an intelligent optimization unit (51) and a coordination and control unit (52); Among them, the intelligent optimization unit (51) includes a state prediction module (511), an efficiency optimization module (512), and a feedback control module (513); The state prediction module (511) predicts the phase change of the mixed organic working medium during the constant-pressure heat absorption process based on the real-time change of the heat source and a thermodynamic model; predicts in real time the phase change of the working medium in the throttling and flashing module (21) to determine the evaporation amount of the low-boiling-point component; and predicts the thermodynamic properties of the working medium through a regression model to adjust the heat exchange process and the pressurization strategy; The efficiency optimization module (512) passes through analysis, adjusts the opening degree of the throttling module, and introduces the viscosity correction factor and the friction factor affected by the deposits on the inner surface of the pipeline into the analysis formula for optimization to give priority to the evaporation of low-boiling components; adjusts the pressure ratios and loads of the adiabatic compression module (22) and the adiabatic expansion module (23) through the genetic algorithm; and adjusts the operating parameters of the heat exchanger according to the real-time working medium flow rate and temperature. The feedback control module (513) adjusts the operating state of the pump module in real time by monitoring the proportion of the working medium in the mixing tank and the pressure of the booster pump in the working medium mixing and pressurization unit (4); Among them, the coordination and control unit (52) includes a flashing and compression linkage control module (521), an expansion and mixing synchronous optimization module (522), and a waste heat recovery process coordination module (523); The flashing and compression linkage control module (521) based on the prediction of the working medium phase change, monitors in real time the mass fraction of the gaseous working medium in the flashing module, and dynamically adjusts the operating state of the adiabatic compression module (22) based on the mass fraction and a model predictive control algorithm; The waste heat recovery process coordination module (523) based on the feedback control module (513) monitors the heat transfer efficiency of each heat exchange module and adjusts the flow rate and temperature of the cooling medium. The expansion and mixing synchronous optimization module (522) based on the efficiency optimization module (512) monitors the power output, the temperature and pressure of the working medium of the adiabatic expansion module (23), and synchronously adjusts with the proportion of the working medium in the mixing tank.

8. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 7, wherein The said The analysis is as follows: Among them, E sf represents the change of the working fluid; m sf represents the mass flow rate of the working fluid; C sf represents the average specific heat capacity of the working fluid; T sf represents the temperature of the working fluid after throttling; T0 represents the ambient temperature; The viscosity of a fluid affects the resistance to flow and heat transfer characteristics. Based on the viscosity, flow velocity, and Reynolds number of the fluid, a viscosity correction factor α is established u : Among them, β represents the intrinsic viscosity of the fluid; k represents a constant correction factor; v represents the flow velocity; d represents the inner diameter of the pipeline; Re represents the Reynolds number; The sediment causes an increase in the surface roughness of the pipeline. The roughness of the inner surface of the pipeline is corrected, and the thickness of the sediment is expressed as the thickness of the sediment layer between the fluid and the pipeline surface: θ eff = θ or + γ s ; where θ eff represents the effective surface roughness considering sediment; θ or represents the original roughness of the pipeline without sediment; γ s represents the sediment thickness; The sediment increases the roughness of the inner surface of the pipeline, and the friction factor f ro It is corrected according to the effective roughness: Introduce the viscosity correction factor α u and the friction factor f affected by the deposits on the inner surface of the pipeline ro into the analysis formula for optimization: Among them, E sf1 represents the change of the optimized working fluid.

9. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 8, characterized in that: The flashing and compression linkage control module (521) dynamically adjusts the operating state of the adiabatic compression module (22) based on the mass fraction and a model predictive control algorithm, including the following steps: S3.

1. Monitor in real time the mass fraction of the gaseous working medium in the flashing module and transmit the mass fraction as a feedback signal to the control system; S3.

2. Determine the target gaseous mass fraction; S3.

3. Predict the future state through a model predictive control algorithm based on the current gas-phase mass fraction and compressor pressure, formulate an optimization problem to optimize the control input, and introduce a gas-liquid separation efficiency parameter into the optimization problem formula of the predictive control algorithm for optimization; S3.

4. Dynamically adjust the operating state of the compressor according to the optimization results of the model predictive control algorithm.

10. The cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle according to claim 9, characterized in that: In the above S3.3, the optimization problem formula is: Among them, r(t) represents the control input variable; wga(i) represents the actual gas-phase mass fraction at the i-th step; w gat (i) represents the target gas-phase mass fraction at the i-th step; P co (i) represents the output pressure of the actual adiabatic compression module (22) at the i-th step; P cot (i) represents the target output pressure of the adiabatic compression module (22) at the i-th step; Q represents the weighted matrix of the output pressure error of the adiabatic compression module (22); R represents the weighted matrix of the output pressure error of the adiabatic compression module (22); i represents the index for traversing the prediction horizon; t represents time; N represents the length of the prediction horizon; Considering the influence of the gas-liquid separation efficiency in the flash module on the quality of the input gas of the compressor, introduce a gas-liquid separation efficiency parameter into the optimization problem formula of the predictive control algorithm for optimization: Incorporate the gas-liquid separation efficiency d(t) as another control variable into the optimization problem formula to penalize the negative impact brought by low separation efficiency: Among them, d1(t) represents the target gas-liquid separation efficiency; represents the penalty coefficient; A represents the weighted matrix of the separation efficiency error.

11. A method for recovering and utilizing cryogenic thermal energy based on an advanced thermodynamic cycle, which is used for the cryogenic thermal energy recovery and utilization system based on an advanced thermodynamic cycle as described in any one of claims 1-10, characterized in that, It includes the following steps: S4.

1. Pre-treat the low-temperature heat source and transmit the heat data to the working fluid through the heat exchange module; S4.

2. Receive the heat data for heat data conversion and working fluid compression; S4.

3. Combine the Rankine cycle to transfer heat energy to do external work; S4.

4. Convert the pressure energy into cooling energy through the adiabatic expansion pressure energy recovery module; S4.

5. Mix the working fluids in different states and boost the pressure of the mixed working fluid; S4.

6. Through intelligent optimization and coordinated control, predict, adjust and optimize each process of the heat energy recovery system in real time.

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