Multi-heat-source organic Rankine cycle power generation and energy storage system and control method thereof

Abstract

The invention discloses a multi-heat-source organic Rankine cycle power generation and energy storage system and a control method of the multi-heat-source organic Rankine cycle power generation and energy storage system, and belongs to the technical field of waste heat recovery. An organic Rankine cycle loop comprising at least two parallel evaporation units, a generator set with a first expansion machine and a second expansion machine and a compressed air energy storage module driven by a working medium are arranged, and a flow path control assembly capable of switching flow paths is matched, so that the system can utilize multiple heat sources independently. According to the structure, when a heat source is sufficient, the system can realize power generation and energy storage in parallel; when the heat source is insufficient, the stored compressed air can be used for driving the second expansion machine to supplement power generation. The system can adapt to fluctuation characteristics of multiple heat sources, especially intermittent heat sources, effectively overcomes the defect that a traditional ORC system is highly dependent on continuity of the heat sources, and realizes continuous and stable power output under the condition of heat source fluctuation.

Description

Technical Field

[0001] This application relates to the field of waste heat recovery technology, and in particular to a multi-heat source organic Rankine cycle power generation and energy storage system and its control method. Background Technology

[0002] Organic Rankine Cycle (ORC) power generation technology is an effective way to recover and utilize medium- and low-temperature heat sources such as industrial waste heat and geothermal energy. However, in practical applications, the operational efficiency of traditional ORC power generation systems is highly dependent on the continuity and stability of the heat source. When the heat source itself is multi-channel and has intermittent and fluctuating characteristics (e.g., periodically emitted industrial waste heat and flue gas), existing systems cannot maintain power generation when the heat source is interrupted, nor can they efficiently store energy when the heat source is excessive, resulting in drastic fluctuations in power output and failing to meet continuous and stable power supply demands. Summary of the Invention

[0003] This application provides a multi-heat-source organic Rankine cycle power generation and energy storage system and its control method, which can generate electricity continuously under intermittent heat sources, thereby at least partially solving the above-mentioned technical problems.

[0004] To achieve the above objectives, according to a first aspect of this application, a multi-heat-source organic Rankine cycle power generation and energy storage system is provided, comprising: An organic Rankine loop includes a condenser, a working fluid pump, and at least two evaporation units connected in parallel via piping, each of the evaporation units being connected to a heat source; An expansion generator set, in fluid communication with the condenser, includes a first expander, a second expander, and a generator; A compressed air energy storage module includes an expansion compressor driven by a working fluid and an air storage tank connected to the expansion compressor; The flow path control component is configured as follows: In the first mode, the working fluid of at least one of the evaporation units is led to the expansion compressor, and the working fluid of at least another evaporation unit is led to the first expander to drive the generator to generate electricity; In the second mode, the flow path from the evaporation unit to the expansion compressor is cut off, the working fluid of each evaporation unit is led to the first expander, and the gas storage tank is controlled to release compressed air to the second expander to drive the generator to generate electricity.

[0005] In some embodiments, the flow path control assembly includes a control valve group configured to: The working fluid outlet of each of the evaporation units is selectively connected in fluid communication with the inlet of the first expander and the inlet of the expansion compressor; and, The distribution ratio of the working fluid from the same evaporation unit to the first expander and the expansion compressor is controlled.

[0006] In some embodiments, the working fluid outlet of at least one of the evaporation units is in fluid communication with the inlet of the first expander via a common flow path, wherein at least one regulating valve of the control valve group is provided on the common flow path, and the regulating valve is used to control the on / off of all working fluids flowing through the common flow path and / or regulate their flow rate.

[0007] In some embodiments, the flow path control component includes a bypass flow path that fluidly connects the downstream of the working fluid outlet of at least one of the evaporation units to the upstream of the inlet of the condenser, and the bypass flow path is provided with a bypass valve.

[0008] In some embodiments, each of the evaporation units includes a preheater and an evaporator arranged in series; The working fluid inlet of the preheater is used to receive working fluid from the working fluid pump, and its working fluid outlet is connected to the working fluid inlet of the evaporator. The heat source flows sequentially through the evaporator and the preheater, or sequentially through the preheater and the evaporator.

[0009] In some embodiments, the flow path control assembly includes a control valve disposed in the flow path between the gas storage tank and the inlet of the second expander.

[0010] In some embodiments, the first expander and the second expander are coaxially arranged and jointly drive the generator.

[0011] In some embodiments, the organic Rankine loop further includes a collection tank connected between the condenser and the working fluid pump; The evaporation unit and / or the liquid collection tank are equipped with a liquid level monitoring device and a pressure relief device.

[0012] According to a second aspect of this application, a control method is provided, applied to a multi-heat-source organic Rankine cycle power generation and energy storage system as described in the first aspect, the control method comprising: In response to the first operating condition, a first control strategy is executed: the working fluid from at least one evaporation unit is directed to the expansion compressor to drive its compressed air for energy storage, while the working fluid from at least another evaporation unit is directed to the first expander of the expansion generator set to drive power generation. In response to the second operating condition, a second control strategy is executed: the working fluid flow path from all evaporation units to the expansion compressor is cut off, the working fluid from each evaporation unit is directed to the first expander, and the compressed air from the gas storage tank is controlled to be released to the second expander of the expansion generator set to drive power generation.

[0013] In some embodiments, the step of determining the first operating condition and the second operating condition includes: The actual output power of the generator is compared with a preset power threshold range; When the actual output power is higher than the upper limit of the threshold range, it is determined to be the first operating condition; When the actual output power is lower than the lower limit of the threshold range, it is determined to be the second operating condition.

[0014] In some embodiments, the preset power threshold range is associated with the system's rated power output W0; The upper limit of the threshold range is higher than the rated power generation W0, and the lower limit of the threshold range is lower than the rated power generation W0.

[0015] In some embodiments, the preset power threshold range is defined by an upper threshold and a lower threshold; The upper limit threshold is 105% of the rated power generation W0, and the lower limit threshold is 90% of the rated power generation W0.

[0016] In some embodiments, the first control strategy further includes: Adjust the ratio of the working fluid flow rate to the expansion compressor to the working fluid flow rate to the first expander.

[0017] In some embodiments, when the first control strategy is executed, if only some of the heat source parameters connected to the evaporation units exceed their rated values: The working fluid from the evaporation unit, whose heat source parameters exceed the rated values, is introduced to the expansion compressor; The working fluid from the evaporation unit, whose heat source parameters do not exceed the rated values, is introduced to the first expander.

[0018] In some embodiments, a third control strategy is also included: In response to system startup, shutdown, or overpressure, the bypass valve is opened to direct the working fluid of at least one evaporation unit to the condenser through the bypass path, allowing it to bypass the expansion compressor and the expansion generator set.

[0019] In the multi-heat-source organic Rankine cycle (ORC) power generation and energy storage system of this application embodiment, by setting up an organic Rankine cycle loop including at least two parallel evaporation units, a generator set with a first expander and a second expander, and a compressed air energy storage module driven by a working fluid, and in conjunction with a flow path control component with switchable flow paths, the system can utilize multiple heat sources independently. This structure allows the system to achieve power generation and energy storage in parallel when heat sources are sufficient; when heat sources are insufficient, the stored compressed air can be used to drive the second expander to supplement power generation. This system can adapt to the fluctuating characteristics of multiple heat sources, especially intermittent heat sources, effectively overcoming the shortcomings of traditional ORC systems that are highly dependent on the continuity of heat sources, and achieving continuous and stable power output under fluctuating heat source conditions.

[0020] The control method of this application implements corresponding control strategies in response to different operating conditions: in the first operating condition, the working fluid is allocated for simultaneous power generation and energy storage; in the second operating condition, the energy storage path is cut off and compressed air is released to supplement power generation. This method dynamically manages and redistributes the system's energy flow, enabling the system to autonomously and flexibly adjust its operating state according to real-time heat source conditions. This not only ensures the continuity of power generation under intermittent heat source conditions but also significantly improves the system's adaptability to different heat source conditions and overall energy utilization efficiency.

[0021] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0024] Figure 1 This is a schematic diagram of the structure of the multi-heat source organic Rankine cycle power generation and energy storage system provided in Embodiment 1 of this application; Figure 2 This is a schematic diagram of the structure of the multi-heat source organic Rankine cycle power generation and energy storage system provided in Embodiment 2 of this application; Figure 3 This is a schematic diagram of the structure of the multi-heat source organic Rankine cycle power generation and energy storage system provided in Embodiment 3 of this application; Figure 4 This is a schematic flowchart of a control method provided in an embodiment of this application; Figure 5 This is another schematic flowchart of the control method provided in the embodiments of this application; Figure 6 This is a schematic diagram of the third process of the control method provided in the embodiments of this application; Explanation of reference numerals in the attached figures: 100 - Organic Rankine cycle loop; 110 - Piping; 120 - Condenser; 130 - Working fluid pump; 140 - Evaporation unit; 140a - First evaporation unit; 141a - First preheater; 142a - First evaporator; 140b - Second evaporation unit; 141b - Second preheater; 142b - Second evaporator; 150 - Collection tank; 200 - Expansion generator set; 210 - First expander; 220 - Second expander; 230 - Generator; 300 - Compressed air energy storage module; 310 - Expansion compressor; 320 - Air tank; 400 - Flow path control assembly; 410 - Control valve group; 410a - First regulating valve; 410b - Second regulating valve; 410c - Third regulating valve; 410d - Fourth regulating valve; 420 - Bypass flow path; 421 - Bypass valve; 430 - Control valve; 440a - First on / off valve; 440b - Second on / off valve; 500 - Common flow path. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0026] like Figure 1 As shown in Embodiment 1 of this application, a multi-heat-source organic Rankine cycle power generation and energy storage system is provided. This system can effectively utilize multiple independent heat sources and maintain stable power generation when heat sources fluctuate or are interrupted.

[0027] The core of the system includes an organic Rankine cycle loop 100, an expander generator set 200, a compressed air energy storage module 300, and a flow path control component 400.

[0028] The Organic Rankine Cycle 100 includes a condenser 120, a working fluid pump 130, and at least two evaporation units 140 connected in parallel via piping 110. Each evaporation unit 140 is independently configured to connect to a heat source, such as a stream of industrial wastewater, a stream of process flue gas, or a stream of geothermal fluid. By configuring at least two parallel evaporation units 140, the system can simultaneously accommodate multiple types of waste heat resources from different locations, improving the flexibility and total amount of energy harvesting. The following description uses a specific example of a system with two evaporation units 140 (a first evaporation unit 140a and a second evaporation unit 140b), where the first evaporation unit 140a is connected to heat source a, and the second evaporation unit 140b is connected to heat source b. It is understood that when three or more evaporation units 140 are present, the system's integration capability for multiple heat sources is further enhanced.

[0029] The expander generator set 200 is in fluid communication with the condenser 120 and includes a first expander 210, a second expander 220, and a generator 230. The first expander 210 is mainly used to receive organic working fluid vapor to drive power generation, while the second expander 220 is mainly used to receive compressed air to drive power generation.

[0030] The compressed air energy storage module 300 includes an expansion compressor 310 driven by an organic working fluid and an air storage tank 320 connected to the outlet of the expansion compressor 310. The expansion compressor 310 can be directly driven by the kinetic energy of the high-pressure working fluid vapor in the organic Rankine cycle, enabling direct energy conversion and storage.

[0031] The flow path control component 400 is configured to perform different operating modes to cope with changing heat source conditions.

[0032] In the first mode, the system handles situations where there is sufficient or excessive heat source. In this mode, the flow path control component 400 guides high-pressure working fluid vapor from at least one evaporation unit 140 to the expansion compressor 310, driving it to operate and compressing air before storing it in the gas storage tank 320, thus completing the energy storage process. Simultaneously, the flow path control component 400 guides high-pressure working fluid vapor from at least another evaporation unit 140 to the first expander 210, driving it to rotate and powering the generator 230 to generate electricity. That is, in this mode, the system can use only one working fluid for energy storage and another for power generation; or, when there are multiple heat sources and multiple evaporation units 140, several working fluids can be combined to drive the expansion compressor 310, while the remaining working fluids can be combined to drive the first expander 210, achieving parallel operation of power generation and energy storage.

[0033] In the second mode, the system addresses situations where the heat source is insufficient. In this mode, the flow path control component 400 cuts off the flow path from all evaporation units 140 to the expansion compressor 310, stopping the energy storage process. Simultaneously, it guides all high-pressure working fluid steam generated by the evaporation units 140 to the first expander 210 to maximize the utilization of limited thermal energy for power generation. To compensate for the decrease in power generation caused by insufficient heat source, the flow path control component 400 also controls the gas storage tank 320 to release the stored high-pressure air. This high-pressure air flows through and drives the second expander 220 to rotate, thereby driving the generator 230 to supplement power generation and maintain a stable total output power.

[0034] The multi-heat-source organic Rankine cycle power generation and energy storage system in this embodiment can couple organic Rankine cycle power generation with compressed air energy storage technology, solving the industry problem that traditional systems cannot generate electricity continuously and stably under intermittent heat source conditions.

[0035] Optionally, the first expander 210 and the second expander 220 can be in the form of turbine expanders, and they can be coaxially mounted, meaning that the rotors of both are mounted on the same main shaft, jointly driving a generator 230. This coaxial arrangement is compact and can effectively reduce the equipment footprint and mechanical transmission losses. Its working principle is as follows: high-pressure organic working fluid vapor is introduced into the first expander 210, driving its impeller to rotate and converting the thermal and pressure energy of the working fluid into mechanical energy; similarly, high-pressure compressed air is introduced into the second expander 220, driving its impeller to rotate and converting the air pressure energy into mechanical energy. The rotational mechanical energy generated by the two expanders acts together on the same shaft, which ultimately drives the rotor of the generator 230 to cut magnetic field lines, thereby generating electrical energy.

[0036] The expander compressor 310 in the compressed air energy storage module 300 is directly driven by high-pressure organic working fluid vapor from the evaporation unit 140. Optionally, the expander compressor 310 includes an expander and a compressor, with the high-pressure organic working fluid vapor driving the expander to operate the compressor. Alternatively, the expander compressor 310 may be structurally similar to an expander, essentially a turbomachinery driven by the working fluid. When the high-pressure working fluid flows through its nozzle and impacts the impeller, it releases kinetic energy to drive the compressor main shaft to rotate at high speed, thereby compressing the intake air. The compressed high-temperature, high-pressure air is then introduced into the air storage tank 320 for storage, completing the conversion and storage process from electrical energy to pressure potential energy.

[0037] In some embodiments, the flow path control assembly 400 includes a control valve assembly 410. The control valve assembly 410 is configured to perform at least two core functions: first, to enable the working fluid outlet of each evaporation unit 140 to selectively establish fluid communication with the inlet of the first expander 210 and the inlet of the expansion compressor 310; and second, to adjust the distribution ratio of the working fluid from the same evaporation unit 140 between the first expander 210 and the expansion compressor 310.

[0038] In practice, the control valve assembly 410 can be arranged in different ways to adapt to different system integration requirements.

[0039] Combination Figure 1 As shown in one configuration, the control valve assembly 410 can be equipped with two independent regulating valves at the working fluid outlet of each evaporation unit 140. One regulating valve is installed in the flow path leading to the first expander 210, and the other regulating valve is installed in the flow path leading to the expansion compressor 310. By controlling the opening of these two valves separately, it is possible to precisely control whether the working fluid flowing out of the evaporation unit 140 flows entirely to the expander, entirely to the compressor, or simultaneously to both in any proportion. For example, when the heat source of an evaporation unit 140 is very abundant, both regulating valves can be opened simultaneously, using part of the working fluid for power generation and part for energy storage, and the distribution ratio can be optimized by adjusting the valve opening.

[0040] Please refer to the following: Figure 1 and Figure 2 In a specific embodiment comprising two evaporation units 140, namely a first evaporation unit 140a and a second evaporation unit 140b, the control valve group 410 in the flow path control assembly 400 may specifically consist of four regulating valves to achieve precise flow path control.

[0041] A first regulating valve 410a is disposed in the flow path between the working fluid outlet of the first evaporation unit 140a and the inlet of the first expander 210. This valve is used to control the on / off state and flow rate of the working fluid flowing from the first evaporation unit 140a to the first expander 210. A second regulating valve 410b is disposed in the flow path between the working fluid outlet of the first evaporation unit 140a and the inlet of the expander compressor 310. This valve is used to control the on / off state and flow rate of the working fluid flowing from the first evaporation unit 140a to the expander compressor 310.

[0042] The third regulating valve 410c is located in the flow path between the working fluid outlet of the second evaporation unit 140b and the inlet of the expansion compressor 310. This valve controls the on / off state and flow rate of the working fluid flowing from the second evaporation unit 140b to the expansion compressor 310. The fourth regulating valve 410d is located in the flow path between the working fluid outlet of the second evaporation unit 140b and the inlet of the first expander 210. This valve controls the on / off state and flow rate of the working fluid flowing from the second evaporation unit 140b to the first expander 210.

[0043] By independently and collaboratively operating the opening degrees of these four regulating valves, the system can flexibly achieve various operating states. For example, when it is necessary to use all the working fluid of the first evaporation unit 140a to drive the expansion compressor 310 and all the working fluid of the second evaporation unit 140b to drive the first expander 210, the second regulating valve 410b and the third regulating valve 410c can be opened, while the first regulating valve 410a and the fourth regulating valve 410d can be closed. Similarly, when it is necessary to use all the working fluid of both evaporation units 140 for power generation, the first regulating valve 410a and the fourth regulating valve 410d can be opened, while the second regulating valve 410b and the third regulating valve 410c can be closed. Furthermore, when the heat source of a certain evaporation unit 140 is excessive, its corresponding two regulating valves can be opened simultaneously (for example, the first regulating valve 410a and the second regulating valve 410b can be opened simultaneously). By adjusting the opening ratio of the two valves, the working fluid generated by the evaporation unit 140 can be distributed to the first expander 210 and the expansion compressor 310 as needed.

[0044] Combination Figure 1 As shown, the control valve assembly 410 can be arranged in a partially integrated manner. For example, the working fluid outlet of at least one evaporation unit 140 can be connected to the inlet of the first expander 210 through a common flow path 500, and a regulating valve (i.e., Figure 1 The first regulating valve 410a is used in this case. When the second evaporation unit 140b supplies working fluid to the first expander 210, the first regulating valve 410a also needs to be opened. Therefore, the fourth regulating valve 410d is not required, and the second evaporation unit 140b and the first evaporation unit 140a share the first regulating valve 410a to control the flow rate and on / off state of the working fluid supplied to the first expander 210. Furthermore, for the first evaporation unit 140a, when all the working fluid needs to be used for power generation, the second regulating valve 410b leading to the expander compressor 310 can be closed, and the entire flow rate can be controlled solely by the first regulating valve 410a on the shared flow path 500. When flow splitting is required, the opening degrees of both the first regulating valve 410a and the second regulating valve 410b are adjusted simultaneously.

[0045] exist Figure 2In the embodiment shown, no regulating valve is provided on the common flow path 500, and the regulating valves corresponding to each evaporation unit 140 are independent. This valve group layout consisting of multiple independent regulating valves provides the system with a greater degree of control flexibility.

[0046] In some embodiments, the flow path control assembly 400 further includes a bypass flow path 420. The bypass flow path 420 fluidly connects the downstream of the working fluid outlet of at least one evaporation unit 140 to the upstream of the inlet of the condenser 120. A bypass valve 421 is provided on the bypass flow path 420 for controlling the opening and closing of the flow path.

[0047] By setting up a bypass flow path 420, abnormal operating conditions or special operational needs of the system can be handled. Specifically, during system startup, the heat source state may not be stable, or the working fluid circulation needs to be established in advance. At this time, the bypass valve 421 can be opened, allowing the working fluid from the evaporator unit 140 to return directly to the condenser 120 without passing through the expander generator set 200 and the expander compressor 310, completing a basic cycle and helping the system smoothly transition to the working state. During normal or emergency system shutdown, the bypass valve 421 can also be opened to quickly relieve the working fluid pressure after the evaporator unit 140 and short-circuit the working fluid circulation, accelerating the system shutdown process and ensuring equipment safety. In addition, when the system detects an abnormally high pressure at a certain point, indicating a risk of overpressure, the bypass valve 421 can be opened in a controlled manner as a pressure relief channel, diverting part or all of the working fluid to the condenser 120 to prevent excessive system pressure from damaging the equipment.

[0048] In one specific example, each evaporation unit 140 can be equipped with an independent bypass flow path 420 and a corresponding bypass valve 421 to achieve independent safety control of each heat source channel. In another example, a general bypass flow path 420 can also be set up to collect the working fluid from all or several of the evaporation units 140 and then connect it to the condenser 120. A bypass valve 421 is set on this general bypass flow path 420 for centralized control.

[0049] In some embodiments, each evaporation unit 140 includes a preheater and an evaporator arranged in series. In the working fluid flow path, the working fluid inlet of the preheater receives liquid organic working fluid pressurized and delivered from the working fluid pump 130. The working fluid first flows through the preheater, where it is initially heated, raising its temperature. Subsequently, the initially heated working fluid enters the working fluid inlet of the evaporator, where it absorbs a large amount of heat and eventually transforms into high-pressure steam with a certain degree of superheat. This high-pressure steam flows out from the working fluid outlet of the evaporator and enters subsequent work or energy storage stages.

[0050] Optionally, the heat source fluid (such as high-temperature flue gas or heat transfer oil) can first flow through the evaporator, releasing its main heat to evaporate the working fluid. Then, the cooled heat source fluid exiting the evaporator flows through the preheater, utilizing its residual heat to preheat the working fluid. This achieves cascaded utilization of thermal energy, conforming to the thermodynamic principle of high-temperature sections driving high-temperature processes and low-temperature sections driving low-temperature processes, thus helping to improve overall thermal efficiency. Alternatively, the flow direction of the heat source fluid can be reversed, i.e., flowing through the preheater first and then through the evaporator. This arrangement can also complete the heating process of the working fluid.

[0051] When the system includes two evaporation units 140, namely a first evaporation unit 140a and a second evaporation unit 140b, the first evaporation unit 140a includes a first preheater 141a and a first evaporator 142a arranged in series. The second evaporation unit 140b also includes a second preheater 141b and a second evaporator 142b arranged in series. The two evaporation units 140 are arranged in parallel on the working fluid flow path.

[0052] To achieve independent control of the parallel branches and precise distribution of the working fluid flow, two on / off valves are installed downstream of the outlet of the working fluid pump 130. Specifically, the first on / off valve 440a is located in the flow path between the outlet of the working fluid pump 130 and the working fluid inlet of the first preheater 141a, and is used to control the overall on / off of the working fluid entering the entire first evaporation unit 140a. The second on / off valve 440b is located in the flow path between the outlet of the working fluid pump 130 and the working fluid inlet of the second preheater 141b, and is used to control the overall on / off of the working fluid entering the entire second evaporation unit 140b.

[0053] By operating the first on / off valve 440a and the second on / off valve 440b, the system can implement various operating strategies. For example, when only the heat source connected to the first evaporation unit 140a is available, the first on / off valve 440a can be opened while the second on / off valve 440b is closed, allowing all the working fluid to flow only through the first evaporation unit 140a for heating. Conversely, when only the heat source of the second evaporation unit 140b is available, the second on / off valve 440b is opened while the first on / off valve 440a is closed. When both heat sources are available, the first on / off valve 440a and the second on / off valve 440b are opened simultaneously, allowing the working fluid to flow into the two evaporation units 140 in parallel. In this case, the relative working fluid flow rate entering the two units can be roughly distributed by adjusting the opening degree of the two on / off valves.

[0054] In some embodiments, a control valve 430 of the flow path control assembly 400 is provided in the connection flow path between the air tank 320 and the inlet of the second expander 220. The control valve 430 is used to control the flow path of compressed air from the air tank 320 to the second expander 220 and to regulate its flow rate.

[0055] When compressed air needs to be released for supplemental power generation, such as when the system is operating in the second mode, the control valve 430 is opened. High-pressure air stored in the air tank 320 enters the second expander 220 through this valve and drives it to perform work. By adjusting the opening of the control valve 430, the flow rate and pressure of the compressed air entering the second expander 220 can be precisely controlled, thereby adjusting the output power of the second expander 220 to match the output power of the first expander 210, jointly maintaining the stability of the total power output of the generator 230. When compressed air is not needed for work, the control valve 430 remains closed, preventing leakage of high-pressure air from the air tank 320 and maintaining its energy storage state.

[0056] Reference Figure 3 As shown, in some embodiments, the organic Rankine loop 100 also includes a collection tank 150. The collection tank 150 is connected between the condenser 120 and the working fluid pump 130, and its main function is to collect the liquid working fluid flowing out of the condenser 120 to ensure that the working fluid pump 130 can stably and continuously deliver the working fluid.

[0057] To enhance the safety and stability of the system operation, both the evaporator of the evaporation unit 140 and the liquid collection tank 150 are equipped with liquid level monitoring devices and pressure relief devices. The liquid level monitoring device monitors the evaporation level of the working fluid in the evaporator and the liquid level in the liquid collection tank 150 in real time, preventing excessively high or low liquid levels from affecting heat exchange efficiency or causing pump cavitation. The pressure relief device serves as the final safety guarantee; when the system pressure abnormally rises above the set safety value, it automatically opens to release pressure, preventing equipment damage due to overpressure.

[0058] Optionally, the heat source used in this system can be at least two of various forms of waste heat generated during industrial production, such as hot water, steam, process materials, heat transfer oil, and flue gas. These heat sources can have different temperature levels and flow characteristics, and the system can utilize them simultaneously and independently through parallel evaporation units 140. In particular, this system is also applicable when a low-temperature cold source is present, such as circulating water, seawater, or air. By setting a suitable working fluid, the aforementioned low-temperature medium can be used as the system's heat source.

[0059] Optionally, the working medium circulated in the system can be an organic working medium, and the selection range includes, but is not limited to, low-boiling-point organic compounds such as pentane, butane, or various Freon substitutes.

[0060] Correspondingly, this application also provides a control method for the aforementioned multi-heat-source organic Rankine cycle power generation and energy storage system.

[0061] Reference Figure 4 As shown, the control method includes the following steps: First, continuously monitor key operating parameters of the system, such as the actual output power of generator 230.

[0062] Based on the monitored parameters, the current operating condition of the system is determined. For example, the system operation can be divided into three typical operating conditions. This control method defines two operating conditions that require active intervention to execute specific strategies: When the system is determined to be in a first operating condition, a first control strategy is executed. This first operating condition corresponds to a situation of excess heat source, i.e., after all available heat sources are introduced into the system, the actual power generation is significantly higher than (e.g., greater than 105%) the system's rated power generation W0. Under this condition, the first control strategy is triggered: working fluid from at least one evaporation unit 140 (e.g., the first evaporation unit 140a) is introduced to the expansion compressor 310 to drive its compressed air for energy storage; simultaneously, working fluid from at least another evaporation unit 140 (e.g., the second evaporation unit 140b) is introduced to the first expander 210 of the expansion generator set 200 to drive power generation. This strategy achieves parallel operation of power generation and energy storage, storing excess energy.

[0063] When the system is determined to be in the second operating condition, the second control strategy is executed. This second operating condition corresponds to a situation where the heat source is insufficient, i.e., the actual power generation is lower than (e.g., less than 90%) the rated power generation W0 of the system. Under this condition, the second control strategy is triggered: the working fluid flow path from all evaporation units 140 to the expansion compressor 310 is cut off, stopping the energy storage process; all working fluid from each evaporation unit 140 is led to the first expander 210 to maximize the utilization of available heat energy for power generation; simultaneously, the compressed air is released from the gas storage tank 320 to the second expander 220 to drive it to perform work and generate electricity, in order to supplement the insufficient power generation and maintain the stability of the total output power.

[0064] It should be noted that under conditions of sufficient heat source (actual power generation between 90% and 105% of rated power), the system can maintain normal operation, for example, by generating electricity without storing energy.

[0065] This control method solves the energy management and balance problem under fluctuating conditions of excessive and insufficient heat source by switching between the two strategies mentioned above. Through this adaptive control based on operating condition judgment, the method enables the system to maintain efficient and stable operation when facing variable and intermittent industrial waste heat.

[0066] Reference Figure 5 As shown, in some embodiments, the step of determining the first operating condition and the second operating condition specifically includes: First, monitor and obtain the actual output power of generator 230 in real time.

[0067] The actual output power is then compared with a preset power threshold range. This threshold range is a pre-defined power interval used to objectively measure whether the system's energy input is in a balanced, excessive, or insufficient state.

[0068] Based on the comparison results, the operating condition is determined as follows: When the actual output power exceeds the upper limit of the preset power threshold range, the system is determined to be in the first operating condition. This condition indicates that the total energy of the heat source input to the system is excessive, and the power generation exceeds the stable operating range. The first control strategy needs to be executed to direct the excess energy to the energy storage stage.

[0069] When the actual output power is lower than the lower limit of the preset power threshold range, the system is determined to be in the second operating condition. This condition indicates that the total energy of the heat source input to the system is insufficient, and the power generation is lower than the stable operation requirements. It is necessary to execute the second control strategy to release the energy storage to supplement power generation.

[0070] In some embodiments, the method associates a preset power threshold range with the system's rated power output W0. Specifically, the upper limit of the preset power threshold range is set to be higher than the rated power output W0, while the lower limit is set to be lower than the rated power output W0. This setting defines a reasonable fluctuation buffer around the rated power W0. When the actual power output is higher than this upper limit, it indicates excessive energy input, corresponding to the first operating condition (excessive heat source); when the actual power output is lower than this lower limit, it indicates insufficient energy input, corresponding to the second operating condition (insufficient heat source).

[0071] Specifically, the preset power threshold range is defined by an upper threshold and a lower threshold. The upper threshold is set to 105% of the rated power output W0, and the lower threshold is set to 90% of the rated power output W0. That is, when the actual output power of generator 230 exceeds 1.05W0, the system determines that it enters the first operating condition and executes the first control strategy; when the actual output power is lower than 0.9W0, the system determines that it enters the second operating condition and executes the second control strategy.

[0072] In some embodiments, during the execution of the first control strategy and the distribution of working fluid for simultaneous energy storage and power generation, the control method further includes adjusting the ratio between the working fluid flow rate to the expander compressor 310 and the working fluid flow rate to the first expander 210.

[0073] Specifically, this adjustment is achieved by controlling the opening of the regulating valves in the corresponding flow paths. By changing the valve openings in different flow paths, the distribution of the working fluid flow to the expansion compressor 310 and the first expander 210 can be adjusted. For example, the flow rate of the working fluid to the expansion compressor 310 can be increased, and the flow rate to the first expander 210 can be decreased accordingly; or the opposite adjustment can be made.

[0074] The purpose of this proportional adjustment is to more precisely control the system's operating status. When there is a large amount of excess energy available for energy storage, the proportion of the working fluid driving the expansion compressor 310 can be increased; when it is necessary to prioritize ensuring immediate power generation, the proportion of the working fluid driving the first expander 210 can be increased. Through this adjustment, the system can operate more smoothly and efficiently under conditions of excess heat source.

[0075] Reference Figure 6 As shown, in some embodiments, when executing the first control strategy, if only some of the heat source parameters connected to the evaporation units 140 exceed their rated values, while the heat source parameters of other evaporation units 140 do not exceed their rated values, the following allocation method is adopted: The working fluid from the evaporation unit 140, whose heat source parameters exceed the rated values, is led to the expansion compressor 310 to utilize its excess energy for energy storage.

[0076] The working fluid from the evaporation unit 140, whose heat source parameters do not exceed the rated values, is introduced to the first expander 210 to maintain basic power generation.

[0077] For example, when the system includes a first evaporation unit 140a and a second evaporation unit 140b, if the heat source temperature or flow rate of the first evaporation unit 140a exceeds its design rating, while the heat source parameters of the second evaporation unit 140b are normal, the working fluid generated by the first evaporation unit 140a can be used to drive the expansion compressor 310 for energy storage, and the working fluid generated by the second evaporation unit 140b can be used to drive the first expander 210 for power generation.

[0078] This allocation method enables differentiated utilization of heat sources in different states, prioritizing the conversion of excess heat energy into energy storage while ensuring the system's basic power generation capacity, thereby improving overall energy efficiency.

[0079] In some embodiments, the control method further includes a third control strategy. This strategy is triggered when the system is in startup, normal shutdown, or when an overpressure condition is detected. When any of these conditions occurs, the control system opens the bypass valve 421. At this time, the working fluid from at least one evaporation unit 140 no longer flows through the expansion compressor 310 and the expansion generator set 200, but is instead directly guided to the condenser 120 through the bypass path 420. During system startup, this helps establish working fluid circulation and preheat system components, achieving a smooth start-up. During planned shutdown, it helps the system safely depressurize and gradually stop operation. When abnormal conditions such as overpressure occur, this strategy serves as an important safety protection measure, quickly relieving system pressure, preventing equipment damage, and ensuring operational safety.

[0080] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0081] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0082] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0083] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A multi-heat-source organic Rankine cycle power generation and energy storage system, characterized in that, include: An organic Rankine loop (100) includes a condenser (120), a working fluid pump (130), and at least two evaporation units (140) connected in parallel via a pipe (110), each of the evaporation units (140) being connected to a heat source; An expander generator set (200) is in fluid communication with the condenser (120) and includes a first expander (210), a second expander (220) and a generator (230). The compressed air energy storage module (300) includes an expansion compressor (310) driven by a working fluid and an air storage tank (320) connected to the expansion compressor (310). The flow path control component (400) is configured as follows: In the first mode, the working fluid of at least one of the evaporation units (140) is led to the expansion compressor (310), and the working fluid of at least another evaporation unit (140) is led to the first expander (210) to drive the generator (230) to generate electricity; In the second mode, the flow path from the evaporation unit (140) to the expansion compressor (310) is cut off, the working fluid of each evaporation unit (140) is led to the first expander (210), and the gas storage tank (320) is controlled to release compressed air to the second expander (220) to drive the generator (230) to generate electricity.

2. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 1, characterized in that, The flow path control assembly (400) includes a control valve assembly (410), which is configured to: The working fluid outlet of each of the evaporation units (140) is selectively in fluid communication with the inlet of the first expander (210) and the inlet of the expansion compressor (310); as well as, The distribution ratio of the working fluid from the same evaporation unit (140) to the first expander (210) and the expansion compressor (310) is controlled.

3. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 2, characterized in that, At least one of the working fluid outlets of the evaporation unit (140) is in fluid communication with the inlet of the first expander (210) through a common flow path (500). At least one regulating valve of the control valve group (410) is provided on the common flow path (500), and the regulating valve is used to control the on / off of all working fluids flowing through the common flow path (500) and / or regulate their flow rate.

4. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 1, characterized in that, The flow path control assembly (400) includes a bypass flow path (420) that fluidly connects the downstream of the working fluid outlet of at least one of the evaporation units (140) to the upstream of the inlet of the condenser (120), and a bypass valve (421) is provided on the bypass flow path (420).

5. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 1, characterized in that, Each of the evaporation units (140) includes a preheater and an evaporator arranged in series; The working fluid inlet of the preheater is used to receive working fluid from the working fluid pump (130), and its working fluid outlet is connected to the working fluid inlet of the evaporator; The heat source flows sequentially through the evaporator and the preheater, or sequentially through the preheater and the evaporator.

6. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 1, characterized in that, The flow path control assembly (400) includes a control valve (430) disposed in the flow path between the gas storage tank (320) and the inlet of the second expander (220).

7. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 1, characterized in that, The first expander (210) and the second expander (220) are coaxially arranged and jointly drive the generator (230).

8. The multi-heat-source organic Rankine cycle power generation and energy storage system according to claim 1, characterized in that, The organic Rankine loop (100) also includes a collection tank (150) connected between the condenser (120) and the working fluid pump (130); The evaporation unit (140) and / or the liquid collection tank (150) are equipped with a liquid level monitoring device and a pressure relief device.

9. A control method, characterized in that, The control method, applied to the multi-heat-source organic Rankine cycle power generation and energy storage system as described in any one of claims 1 to 8, comprises: In response to the first operating condition, a first control strategy is executed: the working fluid from at least one evaporation unit (140) is directed to the expansion compressor (310) to drive its compressed air for energy storage, while the working fluid from at least another evaporation unit (140) is directed to the first expander (210) of the expansion generator set (200) to drive power generation. In response to the second operating condition, a second control strategy is executed: the working fluid flow path from all evaporation units (140) to the expansion compressor (310) is cut off, the working fluid from each evaporation unit (140) is directed to the first expander (210), and the gas storage tank (320) is controlled to release compressed air to the second expander (220) of the expansion generator set (200) to drive power generation.

10. The control method according to claim 9, characterized in that, The steps for determining the first operating condition and the second operating condition include: The actual output power of the generator (230) is compared with a preset power threshold range; When the actual output power is higher than the upper limit of the threshold range, it is determined to be the first operating condition; When the actual output power is lower than the lower limit of the threshold range, it is determined to be the second operating condition.

11. The control method according to claim 10, characterized in that, The preset power threshold range is associated with the system's rated power generation W0; The upper limit of the threshold range is higher than the rated power generation W0, and the lower limit of the threshold range is lower than the rated power generation W0.

12. The control method according to claim 11, characterized in that, The preset power threshold range is defined by an upper threshold and a lower threshold; The upper limit threshold is 105% of the rated power generation W0, and the lower limit threshold is 90% of the rated power generation W0.

13. The control method according to claim 9, characterized in that, The first control strategy also includes: Adjust the ratio of the working fluid flow rate to the expansion compressor (310) to the working fluid flow rate to the first expander (210).

14. The control method according to claim 9, characterized in that, When the first control strategy is executed, if only some of the heat source parameters connected to the evaporation unit (140) exceed their rated values: The working fluid from the evaporation unit (140) whose heat source parameters exceed the rated value is introduced to the expansion compressor (310). The working fluid from the evaporation unit (140) whose heat source parameters do not exceed the rated values ​​is introduced to the first expander (210).

15. The control method according to claim 9, characterized in that, It also includes a third control strategy: In response to system startup, shutdown or overpressure, the bypass valve (421) is opened to lead the working fluid of at least one evaporation unit (140) to the condenser (120) through the bypass flow path (420), so that it bypasses the expansion compressor (310) and the expansion generator set (200).

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