An air conditioning system with dual independent cycle circuits and control method

Abstract

This invention discloses an air conditioning system and control method with dual independent circulation loops. The air conditioning system includes a first circulation loop for achieving cooling or heating functions, a second circulation loop for recovering heat or cooling energy and converting it into electrical energy, and a switching component. The first and second circulation loops are independent of each other, and heat exchange occurs between the two loops through a heat exchanger. In cooling mode, the heat exchanger acts as the heat source for the second circulation loop, and in heating mode, the heat exchanger acts as the cold source for the second circulation loop. This invention achieves flexible switching between cooling and heating modes through the switching component, allowing the heat exchanger to recover waste heat during cooling and recover emitted cooling energy during heating, realizing energy recovery under all operating conditions and reducing dependence on external electrical energy. Simultaneously, the independent design of the two loops allows each to select the optimal working fluid, improving circulation efficiency and combining energy-saving and environmental benefits, making it an energy-saving air conditioning device.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an air conditioning system and control method having dual independent circulation loops. Background Technology

[0002] Air conditioning equipment is widely used in building environmental regulation, and its energy consumption problem is becoming increasingly prominent. Traditional air conditioning systems, whether in cooling or heating mode, suffer from inefficient energy utilization or even direct waste.

[0003] During cooling operation, the condenser of an air conditioning system releases a large amount of high-temperature waste heat into the environment. This condensation heat is usually directly discharged into the atmosphere, causing significant energy waste and raising the ambient temperature, resulting in thermal pollution. During heating operation, the outdoor heat exchanger of the air conditioning system releases a large amount of cooling energy into the environment, which is also directly lost and not effectively recovered. Existing waste heat recovery technologies for air conditioning systems are mainly limited to recovering condensation heat through heat exchangers for purposes such as heating domestic hot water. However, due to limitations such as the asynchronous operation of hot water supply and air conditioning, and the mismatch between heat quality and user demand, energy utilization is low, and the overall energy efficiency of the air conditioning system cannot be effectively improved.

[0004] The Organic Rankine Cycle (ORC) is a technology that utilizes low-boiling-point organic working fluids to recover low-grade waste heat and convert it into mechanical or electrical energy, and it has already achieved some applications in the field of industrial waste heat recovery. In recent years, researchers have begun to explore coupling the Organic Rankine Cycle with vapor compression refrigeration cycles to recover waste heat generated during the operation of air conditioning systems. For example, DuPont's patent CN103906821B discloses a working fluid composition for an Organic Rankine Cycle, aiming to improve cycle efficiency; however, this invention mainly focuses on improving the working fluid itself and does not involve system-level integration with air conditioning vapor compression cycles. United Processes' patent CN103174475B discloses a cascaded Organic Rankine Cycle system, but it involves multiple cycles, resulting in a large and complex device that is difficult to apply in small spaces.

[0005] Furthermore, although the related technologies have integrated the organic Rankine cycle into the traditional air conditioning vapor compression cycle loop, achieving partial waste heat recovery during the air conditioning cooling state, the following shortcomings still exist: Firstly, the organic Rankine cycle cannot operate during the air conditioning heating state, failing to solve the problem of cold energy recovery during heating operation; secondly, the vapor compression cycle loop and the organic Rankine cycle loop need to use the same working fluid, but commonly used air conditioning refrigerants are not suitable as the working fluid for the organic Rankine cycle, limiting its efficiency; and thirdly, the integration method and operating condition switching mechanism between the two loops are not yet perfect, making it difficult to achieve efficient coordinated operation between cooling and heating states.

[0006] Therefore, there is an urgent need for an air conditioning system that can simultaneously recover waste heat or waste cold from the air conditioning system in both cooling and heating modes, with two independent circulation loops that can use different working fluids, and which can flexibly switch between the two modes through a switching component, so as to effectively reduce air conditioning energy consumption and reduce environmental thermal pollution. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an air conditioning system and control method with dual independent circulation loops.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide an air conditioning system with dual independent circulation loops, comprising: The first circulation loop is a vapor compression circulation loop, which is used to realize the cooling or heating function of the air conditioning system. The second circulation loop, which is an organic Rankine loop, is used to recover the heat or cold generated during the operation of the first circulation loop and convert it into electrical energy. A switching component is used to switch the operating modes of the first circulation loop and the second circulation loop between a cooling operating state and a heating operating state. The first and second circulation loops are independent of each other, and heat exchange occurs between the two loops through a heat exchanger. In the cooling operation mode, the heat exchanger serves as the heat source for the second circulation loop; In heating mode, the heat exchanger serves as the cold source for the second circulation loop.

[0009] In one specific embodiment, the switching component includes a first four-way valve, a second four-way valve, and a third four-way valve. The switching between cooling and heating modes is achieved by controlling the direction of the first four-way valve, the second four-way valve, and the third four-way valve.

[0010] In one specific embodiment, the first circulation loop further includes a compressor, an indoor unit heat exchanger, and an electronic expansion valve. The heat exchanger, the electronic expansion valve, the indoor unit heat exchanger, the compressor, and the first four-way valve are connected by pipelines to form a circulation loop.

[0011] In one specific embodiment, the second circulation loop further includes a working fluid pump, an outdoor unit heat exchanger, and an expansion power generation component. The heat exchanger, the third four-way valve, the expansion power generation component, the outdoor unit heat exchanger, the second four-way valve, and the working fluid pump are connected by pipelines to form a circulation loop.

[0012] In one specific embodiment, the expansion power generation component includes an expander and a generator, wherein the generator and the expander share a shaft, and the expander drives the generator to rotate to generate electrical energy.

[0013] In one specific embodiment, the first circulation loop uses a first working medium, and the second circulation loop uses a second working medium, wherein the first working medium and the second working medium are different types of working mediums.

[0014] The air conditioning system with dual independent circulation loops of the present invention has the following advantages compared with the prior art: By constructing mutually independent vapor compression circulation loops and organic Rankine circulation loops, and setting up switching components to achieve flexible switching between cooling and heating operation modes, the heat exchanger can act as a heat source for the organic Rankine circulation to recover condensation waste heat in cooling mode and as a cold source for the organic Rankine circulation to recover emitted cold energy in heating mode. This achieves energy recovery and utilization under all air conditioning operating conditions, reducing the air conditioning system's demand for external power. At the same time, the independent design of the two loops allows each to select the optimal working fluid, breaking through the technical limitation of the two loops sharing the same working fluid in traditional schemes, effectively improving circulation efficiency. The reuse design of the heat exchanger also simplifies the system structure, reduces manufacturing costs, and makes it suitable for small space applications. In addition, after some waste heat or waste cold is converted into electrical energy output, the amount of heat or cold energy emitted into the environment is reduced, effectively alleviating the thermal pollution problem caused by air conditioning operation, thus achieving both energy-saving and environmental benefits.

[0015] Secondly, embodiments of the present invention provide an air conditioning control method with dual independent circulation loops, applied to the air conditioning system with dual independent circulation loops as described above, the air conditioning control method with dual independent circulation loops comprising: Identify the operating status of the air conditioning system; The mode is switched according to the working status control switching component; Obtain temperature parameters and determine whether the startup conditions are met; The start and stop of the second loop are controlled based on the judgment result; Control the operation of the working fluid pump; Adjust the load on the expansion generator components.

[0016] In one specific embodiment, the steps of acquiring temperature parameters and determining whether the start-up conditions are met, and controlling the start and stop of the second loop based on the determination result, include: Obtain the temperature value of the heat exchanger and the temperature value of the external environment, and calculate the temperature difference between the two; When the temperature difference value is greater than the preset value, the second circulation loop is activated; When the temperature difference is less than or equal to the preset value, the second circulation loop remains in standby mode.

[0017] In one specific embodiment, the step of adjusting the load of the expansion power generation component includes: monitoring the rotational speed of the expansion power generation component, adjusting the load of the expansion power generation component according to the rotational speed, so that the rotational speed of the expansion power generation component is maintained within a preset rotational speed range.

[0018] In one specific embodiment, the step of adjusting the load of the expansion power generation component further includes: When the rotational speed of the expansion power generation component exceeds the upper limit of the preset rotational speed range, the load on the expansion power generation component is increased; When the rotational speed of the expansion power generation component is lower than the lower limit of the preset rotational speed range, the load on the expansion power generation component is reduced; When the rotational speed of the expansion power generation component is within the preset rotational speed range, the current load of the expansion power generation component is maintained.

[0019] The air conditioning control method with dual independent circulation loops of the present invention has the following advantages compared with the prior art: By identifying the working state of the air conditioning system and controlling the switching component to switch the operating mode according to the state, the second circulation loop obtains the corresponding heat source or cold source in the cooling and heating working states respectively. Then, the start-up conditions are determined based on the temperature difference between the heat exchanger and the external environment, and the start and stop of the second circulation loop are controlled. This ensures that the organic Rankine cycle only operates when the temperature difference meets the working conditions to avoid inefficient operation. At the same time, the operation control of the working fluid pump and the load adjustment of the expansion power generation component ensure that the loop is always maintained in a stable and efficient operating range. The above control logic forms a complete closed loop from working condition identification, mode switching, temperature difference determination to component adjustment. The organic Rankine cycle can stably and efficiently recover waste heat or waste cold and convert it into electrical energy under all air conditioning operating conditions. At the same time, it effectively prevents the expansion power generation component from causing safety risks due to excessively high or low speed, improves the safety and reliability of system operation, and thus reduces the overall energy consumption of the air conditioning system while taking into account the operational stability.

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of an air conditioning system with dual independent circulation loops in cooling operation, provided by the present invention; Figure 2 A schematic diagram of an air conditioning system with dual independent circulation loops in heating mode, provided by the present invention; Figure 3 The temperature entropy diagram of the organic Rankine cycle for air conditioning refrigerant R32; Figure 4 The organic Rankine cycle temperature-entropy diagram for air conditioning refrigerant R245fa; Figure 5 This is a schematic flowchart of an air conditioning control method with dual independent circulation loops provided in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0030] See Figures 1 to 4 As shown, this invention discloses a specific embodiment of an air conditioning system with dual independent circulation loops, comprising: The first circulation loop is a vapor compression circulation loop, which is used to realize the cooling or heating function of the air conditioning system. The second circulation loop, which is an organic Rankine loop, is used to recover the heat or cold generated during the operation of the first circulation loop and convert it into electrical energy. A switching component is used to switch the operating modes of the first circulation loop and the second circulation loop between a cooling operating state and a heating operating state. The first and second circulation loops are independent of each other, and heat exchange occurs between the two loops through a heat exchanger. In the cooling operation mode, the heat exchanger serves as the heat source for the second circulation loop; In heating mode, the heat exchanger serves as the cold source for the second circulation loop.

[0031] Among them, see Figures 1 to 2 As shown, there are two cyclic loops, in Figure 1 and Figure 2 The solid and dashed lines are respectively used to indicate the vapor compression cycle (VCC) loop, which is the loop used in conventional air conditioning systems to achieve cooling / heating. The dashed loop is the organic Rankine cycle (ORC) loop, which is used to extract usable energy from the waste heat / cooling in the VCC loop and convert it into electrical energy. The arrows indicate the direction of the working fluid or refrigerant flow.

[0032] Specifically, the first circulation loop is a vapor compression circulation loop, which enables the air conditioning system to cool or heat the indoor environment. This loop follows the vapor compression refrigeration cycle principle of conventional air conditioning systems, where the refrigerant circulates in the loop, absorbing or releasing heat at the indoor unit's heat exchanger to regulate the indoor temperature. The second circulation loop is an organic Rankine cycle loop, which recovers the heat or cooling generated during the operation of the first circulation loop and converts this energy into electrical energy output. The first and second circulation loops are independent of each other, and their only connection is heat exchange through a heat exchanger. This heat exchanger has two isolated flow channels. The working fluid of the first circulation loop flows through one channel, and the working fluid of the second circulation loop flows through the other channel. The working fluids in the two loops transfer heat only through the metal walls of the heat exchanger and do not mix.

[0033] The switching component adjusts the flow path of the working fluid in both the first and second circulation loops according to the required operating mode of the air conditioning system, enabling the entire system to switch between cooling and heating modes. In cooling mode, the high-temperature, high-pressure refrigerant in the first circulation loop releases heat to the outside as it flows through the heat exchanger. At this temperature, the heat exchanger is at a high temperature. The organic working fluid in the second circulation loop absorbs heat and evaporates as it flows through the heat exchanger. Therefore, in cooling mode, the heat exchanger acts as the heat source for the second circulation loop, while the atmospheric environment acts as the cold source. The working fluid in the second circulation loop releases heat to the atmosphere in the outdoor unit's heat exchanger. In heating mode, the low-temperature, low-pressure refrigerant in the first circulation loop absorbs heat from the outside as it flows through the heat exchanger. At this temperature, the heat exchanger is at a low temperature. The organic working fluid in the second circulation loop releases heat to the heat exchanger and condenses as it flows through it. Therefore, in heating mode, the heat exchanger acts as the cold source for the second circulation loop, while the atmospheric environment acts as the heat source. The working fluid in the second circulation loop absorbs heat from the atmosphere in the outdoor unit's heat exchanger. In this way, the air conditioning system can recover energy that would otherwise be directly lost to the environment through the second circulation loop and convert it into usable power energy in both cooling and heating modes.

[0034] Therefore, by constructing independent vapor compression and organic Rankine cycles and setting switching components to achieve flexible switching between cooling and heating modes, the heat exchanger can function as a heat source for the organic Rankine cycle in cooling mode to recover condensation waste heat, and as a cold source for the organic Rankine cycle in heating mode to recover emitted cooling energy. This enables energy recovery and utilization under all air conditioning operating conditions, reducing the air conditioning system's demand for external electricity. Simultaneously, the independent design of the two cycles allows each to select its optimal working fluid, overcoming the technical limitations of traditional solutions that share the same working fluid, effectively improving cycle efficiency. The reuse design of the heat exchanger also simplifies the system structure and reduces manufacturing costs, making it suitable for small-space applications. Furthermore, after some waste heat or cold is converted into electrical energy output, the amount of heat or cold emitted into the environment is reduced, effectively alleviating the thermal pollution problem caused by air conditioning operation, thus achieving both energy-saving and environmental benefits.

[0035] See Figures 1 to 2 As shown, in one embodiment, the switching component includes a first four-way valve (i.e., four-way valve 1 in the figure), a second four-way valve (i.e., four-way valve 2 in the figure), and a third four-way valve (i.e., four-way valve 3 in the figure). The switching between the cooling working state and the heating working state is achieved by controlling the direction of the first four-way valve, the second four-way valve, and the third four-way valve.

[0036] Specifically, a four-way valve is a commonly used reversing element in air conditioning systems. It changes the connection between its four ports by altering the position of the valve core, thereby changing the flow direction of the working fluid in the circuit. The first four-way valve is located in the first circulation loop, with its four ports connected to the compressor's exhaust and intake ports, the indoor unit heat exchanger, and the heat exchanger, respectively. The second and third four-way valves are located in the second circulation loop. The second four-way valve's four ports are connected to the working fluid pump's outlet and inlet, the outdoor unit heat exchanger, and the heat exchanger, respectively. The third four-way valve's four ports are connected to the expansion generator's outlet and inlet, the heat exchanger, and the outdoor unit heat exchanger, respectively. The reversal of the three four-way valves is controlled uniformly by the air conditioning control panel.

[0037] When the air conditioning system needs to switch from cooling to heating mode, or vice versa, the air conditioning control board simultaneously sends electrical signals to the three four-way valves, driving the valve cores of each valve to actuate and synchronously changing the connection relationship of each valve. The direction of the first four-way valve changes the flow direction of refrigerant in the first circulation loop between the compressor, indoor unit heat exchanger, and heat exchanger, thereby causing the indoor unit heat exchanger and heat exchanger to interchange their functional roles as condenser and evaporator. That is, in cooling mode, the heat exchanger acts as a condenser and the indoor unit heat exchanger acts as an evaporator; in heating mode, the heat exchanger acts as an evaporator and the indoor unit heat exchanger acts as a condenser. The reversing of the second and third four-way valves alters the flow direction of the organic working fluid in the second circulation loop between the heat exchanger, outdoor unit heat exchanger, expansion generator assembly, and working fluid pump. This allows the heat exchanger and outdoor unit heat exchanger to switch functional roles as heat source and cold source; that is, in cooling mode, the heat exchanger acts as an evaporator and the outdoor unit heat exchanger acts as a condenser, while in heating mode, the heat exchanger acts as a condenser and the outdoor unit heat exchanger acts as an evaporator. Through the coordinated reversing of the three four-way valves, the operating modes of the first and second circulation loops are switched synchronously at the same time, ensuring that the two loops are always in a matched operating state.

[0038] Therefore, it can be seen that the synchronous control of three four-way valves enables rapid and accurate switching between cooling and heating modes, ensuring the coordination and consistency of the two circulation loops during mode switching, and improving the system's switching response speed and reliability.

[0039] See Figures 1 to 2 As shown, in one embodiment, the first circulation loop further includes a compressor, an indoor unit heat exchanger, and an electronic expansion valve. The heat exchanger, the electronic expansion valve, the indoor unit heat exchanger, the compressor, and the first four-way valve are connected by pipelines to form a circulation loop.

[0040] Specifically, the first circulation loop further includes a compressor, an indoor unit heat exchanger, and an electronic expansion valve. These components, along with the heat exchanger and the first four-way valve, are connected in a specific sequence via pipelines to form a complete circulation loop. The specific connection relationships are as follows: the compressor's discharge port is connected to the first port of the first four-way valve via a pipeline; the second port of the first four-way valve is connected to the first port of the heat exchanger via a pipeline; the second port of the heat exchanger is connected to the first end of the electronic expansion valve via a pipeline; the second end of the electronic expansion valve is connected to the first port of the indoor unit heat exchanger via a pipeline; the second port of the indoor unit heat exchanger is connected to the third port of the first four-way valve via a pipeline; and the fourth port of the first four-way valve is connected to the compressor's suction port via a pipeline, thereby forming a closed circulation loop.

[0041] The compressor is the power component that drives the refrigerant circulation in the first cycle loop. It compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant, providing energy input for the entire cycle. During refrigeration operation, the high-temperature, high-pressure refrigerant gas exits from the compressor's discharge port, enters through the first port of the first four-way valve and exits through the second port, being guided into the first port of the heat exchanger. In the heat exchanger, it releases heat to the working fluid in the second cycle loop and condenses into a liquid state. The liquid refrigerant then exits from the second port of the heat exchanger, subsequently flowing through the electronic expansion valve where it is throttled and depressurized into a low-temperature, low-pressure gas-liquid two-phase state. It then enters the indoor unit's heat exchanger, absorbs heat from the indoor air, and evaporates, becoming a low-temperature, low-pressure gaseous state. Afterward, it enters through the third port of the first four-way valve and exits through the fourth port, returning to the compressor's suction port, completing the refrigeration cycle. In heating mode, the refrigerant flows in the opposite direction to the cooling mode via the reversing of the first four-way valve. High-temperature, high-pressure refrigerant gas exits from the compressor discharge port, enters through the first port of the first four-way valve, and exits through the third port. It is guided into the indoor unit heat exchanger, releasing heat to the indoor air and condensing into a liquid state. The liquid refrigerant then flows through the electronic expansion valve for throttling and enters the heat exchanger, absorbing heat from the working fluid in the second cycle loop and evaporating. It then returns to the compressor suction port via the second port of the first four-way valve and exits through the fourth port, completing the heating cycle. In both operating modes, the heat exchanger serves as an energy exchange node between the first and second cycle loops, facilitating heat transfer between the refrigerant in the first cycle loop and the organic working fluid in the second cycle loop.

[0042] Therefore, through the above connection relationship and operating principle, the heat exchanger takes on the role of the outdoor heat exchanger in the first circulation loop, replacing the outdoor unit condenser or evaporator in the traditional air conditioning system. At the same time, as the intersection of the two circulation loops, the heat exchanger ensures that the energy exchange between the two loops can be carried out efficiently.

[0043] See Figures 1 to 2As shown, in one embodiment, the second circulation loop further includes a working fluid pump, an outdoor unit heat exchanger, and an expansion generator assembly. The heat exchanger, the third four-way valve, the expansion generator assembly, the outdoor unit heat exchanger, the second four-way valve, and the working fluid pump are connected by pipelines to form a circulation loop.

[0044] Specifically, the second circulation loop further includes a working fluid pump, an outdoor unit heat exchanger, and an expansion generator assembly. These components, along with the heat exchanger, the second four-way valve, and the third four-way valve, are connected in a specific sequence via pipelines to form a complete circulation loop. The specific connection relationships are as follows: the third port of the heat exchanger is connected to the first port of the third four-way valve via a pipeline; the second port of the third four-way valve is connected to the inlet of the expansion generator assembly via a pipeline; the outlet of the expansion generator assembly is connected to the third port of the third four-way valve via a pipeline; the fourth port of the third four-way valve is connected to the first port of the outdoor unit heat exchanger via a pipeline; the second port of the outdoor unit heat exchanger is connected to the first port of the second four-way valve via a pipeline; the second port of the second four-way valve is connected to the inlet of the working fluid pump via a pipeline; the outlet of the working fluid pump is connected to the third port of the second four-way valve via a pipeline; and the fourth port of the second four-way valve is connected to the fourth port of the heat exchanger via a pipeline, thereby forming a closed circulation loop.

[0045] The working fluid pump is the power component that drives the circulation of the organic working fluid in the second circulation loop. It pressurizes the liquid organic working fluid and delivers it to the heat exchanger. The expansion generator is the core component that converts the pressure energy and thermal energy of the working fluid into electrical energy. In the cooling operation, guided by the second and third four-way valves, the liquid organic working fluid, after being pressurized by the working fluid pump, enters the heat exchanger from the fourth port. In the heat exchanger, it absorbs the heat released from the first circulation loop and evaporates into a high-temperature, high-pressure gas. The gaseous working fluid flows out from the third port of the heat exchanger and enters the first port of the third four-way valve. It then flows out through the second port of the third four-way valve and enters the expansion generator. In the expansion generator, it expands and does work, converting pressure energy and thermal energy into mechanical energy, and then into electrical energy. The gaseous working fluid flowing out from the expansion generator enters the outdoor unit heat exchanger, where it releases heat to the atmosphere and condenses into a liquid. The liquid working fluid enters through the second port of the second four-way valve, flows out through the fourth port, and returns to the working fluid pump to complete the cycle. In heating mode, the flow path of the organic working fluid is reversed from that in cooling mode by switching the second and third four-way valves. The liquid working fluid is pressurized by the working fluid pump and enters the heat exchanger. In the heat exchanger, it releases heat to the first circulation loop and condenses into liquid. After flowing out of the heat exchanger, the liquid working fluid is switched by the third four-way valve and enters the expansion generator to generate electricity. The working fluid flowing out of the expansion generator enters the outdoor unit heat exchanger to absorb heat from the atmosphere and evaporate into gas. The gaseous working fluid is switched by the second four-way valve and returns to the working fluid pump to complete the cycle.

[0046] Therefore, through the above connection relationship and operating principle, the second circulation loop can obtain heat or cold from the heat exchanger and generate electricity through the expansion power generation component in both working states. In the cooling state, the outdoor unit heat exchanger acts as the condenser of the second circulation loop to release heat to the atmosphere, and in the heating state, it acts as the evaporator of the second circulation loop to absorb heat from the atmosphere, thus ensuring the normal operation of the second circulation loop under all working conditions.

[0047] See Figures 1 to 2 As shown, in one embodiment, the expansion power generation assembly includes an expander and a generator, the generator and the expander sharing a shaft, and the expander driving the generator to rotate to generate electrical energy.

[0048] Specifically, an expander is a power machine that converts the pressure and thermal energy of a working fluid into rotational mechanical energy. It contains an impeller; the high-temperature, high-pressure gaseous working fluid enters the expander and drives the impeller to rotate, thus achieving energy conversion. The generator is a device that converts mechanical energy into electrical energy. Its rotor and the expander's impeller are mounted on the same shaft. When the expander's impeller rotates, the shaft drives the generator's rotor to rotate synchronously. The coils in the generator's stator cut magnetic lines of force in the rotating magnetic field generated by the rotor, thereby generating an induced electromotive force and outputting electrical energy. The design of the expander and generator sharing a single shaft means that they always maintain the same rotational speed. The mechanical energy output by the expander is directly transferred to the generator without passing through an additional transmission mechanism, reducing energy loss in intermediate stages.

[0049] During the operation of the second circulation loop, the high-temperature, high-pressure gaseous working fluid flows out of the heat exchanger and enters the expander. In the expander, the working fluid expands, depressurizes, and cools, releasing energy that drives the impeller and shaft to rotate. The rotation of the shaft drives the generator rotor to generate electricity. The electricity output from the generator is transmitted to the power module via wires. After rectification and conversion by the rectifier circuit in the power module, this electricity can be combined with electricity from an external power source to power components such as the air conditioning system's compressor, axial fan motor, and working fluid pump. The expander in this expansion-generator assembly serves as the core of the second circulation loop's power output; its operating state directly affects the power generation efficiency and the stability of the entire second circulation loop. Conversely, the generator, as the energy conversion terminal, is affected by its load, which in turn affects the expander's speed. The two are closely linked through their shared shaft.

[0050] Therefore, it can be seen that by setting the expander and generator coaxially, a highly efficient conversion from thermal energy to mechanical energy and then to electrical energy is achieved, reducing transmission losses, improving the overall efficiency of energy recovery, and simplifying the equipment structure, while reducing manufacturing and maintenance costs.

[0051] In one embodiment, the first circulation loop uses a first working medium, and the second circulation loop uses a second working medium, wherein the first working medium and the second working medium are different types of working mediums.

[0052] Specifically, since the first and second circulation loops are independent, the working fluids in the two loops exchange heat only through the pipe walls in the heat exchanger without contacting or mixing with each other. Therefore, the types of working fluids charged in each loop do not affect each other. The first circulation loop, as a vapor compression loop, primarily considers factors such as cooling and heating performance, compressor compatibility, safety, and environmental friendliness when selecting its working fluid. Conventional air conditioning refrigerants such as R32 or R410A can be used. The second circulation loop, as an organic Rankine cycle loop, requires its working fluid to meet specific thermodynamic requirements. Taking the commonly used air conditioning refrigerant R32 as an example, its saturated liquid line in the temperature-entropy diagram is inclined. When R32 expands in the expander, the state point of the working fluid is very close to the saturated vapor line. When there are temperature or pressure disturbances in the system, the state point is very likely to fall into the saturation region, meaning the working fluid partially liquefies in the expander. The impact force of the liquid droplets on the expander impeller is much greater than the gas impact force. This liquid slugging phenomenon significantly reduces the service life of the expander and may even directly damage it. Therefore, R32 is not suitable for use in the organic Rankine cycle. Unlike R32, the saturated liquid line of R245fa is essentially vertical on the temperature-entropy diagram. When R245fa expands in an expander, the working fluid's state point does not fall into the saturation region throughout the expansion process, maintaining a gaseous state and thus avoiding the risk of liquid slugging. Therefore, R245fa is suitable as a working fluid for the organic Rankine cycle. Conventional air conditioning refrigerants such as R410A have similar inclined saturated liquid lines to R32 and are unsuitable for the organic Rankine cycle. Based on these thermodynamic principles, if two loops share the same working fluid, a choice must be made between R32-type refrigerants and R245fa-type refrigerants. Regardless of the choice, the efficiency of the other loop will be severely limited.

[0053] By designing the two circulation loops as completely independent structures with no mixing of working fluids, the first circulation loop can use refrigerants such as R32, which are suitable for vapor compression cycles, to ensure the cooling and heating performance of the air conditioning system. The second circulation loop can independently use working fluids such as R245fa, which are suitable for organic Rankine cycles, to ensure energy recovery efficiency. This overcomes the technical defect of limited circulation efficiency caused by sharing working fluids in traditional schemes.

[0054] More specifically, Figure 3 and Figure 4The diagrams show the saturated liquid line (dashed AC) and saturated vapor line (dashed BC) of the temperature-entropy diagrams for R32 and R245fa, respectively, as well as the organic Rankine cycle curve (solid line). When the working fluid's state point is to the left of the saturated liquid line (dashed AC), it is in the liquid state; when it is between the saturated liquid line and the saturated vapor line, it is in the boiling state of gas-liquid coexistence; and when it is to the right of the saturated vapor line, it is in the gas state.

[0055] The working fluid in ORC needs to go through the following steps: (1) First, the working medium is pressurized by the working medium pump. Before and after pressurization, the working medium is in a liquid state, corresponding to state 3 to 0 in the temperature-entropy diagram. The temperature and entropy of the working medium increase slightly. The working medium pump is also the power source for the movement of the working medium.

[0056] (2) Then the working fluid is transported to the heat source. When the air conditioner is in the cooling state, the heat exchanger is the heat source. When the air conditioner is in the heating state, the outdoor unit heat exchanger is the heat source. After being heated by the heat source, the working fluid undergoes liquid temperature rise (state 0 to state 0.1), boiling (state 0.1 to state 0.2) and superheating process (state 0.2 to state 1), and becomes a high temperature and high pressure gas. During this stage, the temperature and entropy of the working fluid both increase.

[0057] (3) The gaseous working fluid then enters the expander, where it drives the impeller to rotate, outputting power to power a generator and produce electricity. Within the expander, the entropy of the gaseous working fluid increases slightly, while its temperature decreases significantly, corresponding to state points 1 to 2 on the temperature-entropy diagram. This means that pressure and thermal energy are converted into the mechanical energy of the impeller, which is then converted into electrical energy by the generator. The working fluid exiting the expander is still gaseous, but its pressure and temperature are lower. Figure 3 and Figure 4 The differences between the two working refrigerants are evident. The saturated liquid line (BC) of R245fa is essentially vertical, ensuring that state point 2 will not fall into the saturation region (the area enclosed by ABC) during expansion, thus remaining in a gaseous state. In contrast, the saturated liquid line of R32 is inclined, causing state point 2 to be very close to the saturated vapor line (BC). When system disturbances occur, state point 2 may fall into the saturation region, resulting in partial liquefaction of the working refrigerant within the expander. The impact force of the liquid droplets is far greater than that of the gas, reducing the expander's lifespan and potentially damaging it. Commonly used refrigerants in air conditioning, R32 and R410A, exhibit similar characteristics and are unsuitable for organic Rankine cycles.

[0058] (4) The gas flowing out of the expander enters the cold source and is cooled into a liquid state. When the air conditioner is cooling, the outdoor unit heat exchanger is the cold source, and when the air conditioner is heating, the heat exchanger is the cold source. The cooling process is divided into three processes: gaseous cooling (state points 2 to 2.1), constant temperature condensation (state points 2.1 to 2.2), and subcooling (state points 2.2 to 3), which turn the gas into a low-temperature and low-pressure liquid. Then the liquid working fluid re-enters the working fluid pump to start a new cycle.

[0059] Therefore, by using the above method, each of the two independent circulation loops selects the optimal working fluid, which not only ensures the original cooling and heating performance of the air conditioning system, but also maximizes the energy recovery efficiency of the organic Rankine loop.

[0060] See Figure 5 As shown, the present invention also discloses an air conditioning control method with dual independent circulation loops, applied to the air conditioning system with dual independent circulation loops as described above. The air conditioning control method with dual independent circulation loops includes: S110. Identify the operating status of the air conditioning system; Specifically, after the air conditioning system is powered on and started, the control board first reads the operating mode signal set by the user via the remote control or control panel. Simultaneously, it combines this information with temperature data from the indoor and outdoor ambient temperature sensors to comprehensively determine whether the air conditioning system should be in cooling or heating mode. If the user sets the system to cooling mode and the indoor temperature is higher than the set temperature, the control board recognizes the current operating mode as cooling; if the user sets the system to heating mode and the indoor temperature is lower than the set temperature, the control board recognizes the current operating mode as heating.

[0061] The purpose of this identification step is to provide accurate operating condition judgment for subsequent switching component reversing control, ensuring that the system operates in the correct mode. In other words, by identifying the operating condition, it ensures that the reversing operation of the switching component matches the actual needs of the air conditioning system, avoiding switching errors or system malfunctions due to mode misjudgment, providing an accurate execution basis for subsequent control steps, and guaranteeing the normal operation of the air conditioning system in both operating states.

[0062] S120. The switching component is controlled to switch modes according to the working status. Specifically, after identifying the current operating state, the control board sends a corresponding mode switching command to the switching component based on the identification result. If the operating state is identified as cooling, the control board simultaneously sends cooling mode electrical signals to the first, second, and third four-way valves, driving the valve cores of the three four-way valves to synchronously move to the cooling state position. This causes the refrigerant in the first circulation loop to flow along the cooling circulation path, while the organic working fluid in the second circulation loop flows along the cooling recovery path. In this state, the heat exchanger acts as the heat source for the second circulation loop. If the operating state is identified as heating, the control board simultaneously sends heating mode electrical signals to the three four-way valves, driving the valve cores of the three four-way valves to synchronously move to the heating state position. This causes the refrigerant in the first circulation loop to flow along the heating circulation path, while the organic working fluid in the second circulation loop flows along the heating recovery path. In this state, the heat exchanger acts as the cold source for the second circulation loop. The synchronous switching of the three four-way valves ensures that the two circulation loops complete the mode transition at the same time, realizing the overall switching of the system's operating mode.

[0063] In other words, by controlling the switching component to achieve synchronous switching of the two circulation loop operating modes, the first circulation loop and the second circulation loop always remain matched in both cooling and heating operating states, ensuring that the second circulation loop can effectively recover energy in both operating conditions, thus realizing the control basis for energy recovery of the air conditioning system under all operating conditions.

[0064] S130: Obtain temperature parameters and determine whether the start-up conditions are met; Specifically, after the switching component completes the mode switch, the control board collects the current temperature value of the heat exchanger in real time through a first temperature sensor located on the heat exchanger, and simultaneously collects the current temperature value of the external environment in real time through a second temperature sensor located on the outside of the air conditioner outdoor unit. The control board subtracts the two collected temperature values ​​to calculate the temperature difference between the heat exchanger temperature and the external environment temperature. The control board's internal memory stores a preset starting temperature difference value. The specific value of this preset value is determined based on the minimum temperature difference required for the organic working fluid in the second circulation loop to effectively perform work, and is also affected by the setting accuracy of the pressure control element in the loop. The control board compares the calculated temperature difference value with the internally stored preset value to determine whether the current temperature difference meets the conditions for the second circulation loop to start performing work.

[0065] In other words, using the temperature difference between the heat exchanger and the external environment as the start-up criterion avoids inefficient operation and extra power consumption caused by starting the second circulation loop when the temperature difference is insufficient. This ensures that the start-up of the second circulation loop is adapted to the external environmental conditions and the actual operating state of the system, so that the energy recovery process is always carried out under feasible conditions.

[0066] S140. Control the start and stop of the second loop based on the judgment result; Specifically, the control board generates corresponding start / stop control signals based on the temperature difference comparison results. When the temperature difference is greater than a preset value, the control board determines that the current temperature difference conditions meet the requirements for effective work of the organic Rankine cycle, and then sends a start signal to the working fluid pump's drive circuit. The working fluid pump starts running, driving the organic working fluid to circulate in the second circulation loop. The second circulation loop then starts operating, recovering waste heat or waste cold from the first circulation loop and converting it into electrical energy. When the temperature difference is less than or equal to the preset value, the control board determines that the current temperature difference conditions are insufficient to support effective work of the organic Rankine cycle, and therefore does not send a start signal. The working fluid pump remains stopped, and the second circulation loop remains in standby mode, not in operation. When the second circulation loop is already in operation and the temperature difference subsequently drops below the preset value, or when the air conditioning system receives a shutdown command, the control board sends a stop signal to the second circulation loop, executing the shutdown procedure.

[0067] In other words, the second circulation loop is precisely controlled based on the temperature difference judgment results, ensuring that the energy recovery device only operates when the conditions for doing work are met, avoiding extra energy consumption and equipment wear caused by ineffective operation, and realizing adaptive start-stop control of the energy recovery process.

[0068] S150, controls the operation of the working fluid pump; Specifically, after the second circulation loop starts operating, the control board controls the speed of the working fluid pump in real time based on the heat source temperature. The speed of the working fluid pump depends only on the heat source temperature. Its control logic is as follows: the control board obtains the current heat source temperature value through a temperature sensor, calculates the working fluid saturation pressure corresponding to the temperature value obtained by subtracting 2 to 5 degrees Celsius from the heat source temperature, and uses this saturation pressure value as the target value for the working fluid pump outlet pressure. The working fluid pump adjusts its own speed to maintain the outlet pressure at the target value. Taking the refrigeration operation as an example, the heat source is a heat exchanger. The control board reads the temperature value of the heat exchanger. For example, if the heat exchanger temperature is 45 degrees Celsius, the control board subtracts 3 degrees Celsius to get 42 degrees Celsius, and then queries the working fluid property database to obtain the saturation pressure value of the organic working fluid at 42 degrees Celsius. The working fluid pump uses this pressure value as the target outlet pressure to adjust its speed. The 2 to 5 degree Celsius temperature difference is a reserved heat transfer temperature margin to ensure that heat can be effectively transferred from the first circulation loop to the working fluid in the second circulation loop. Its function is to ensure that the organic working fluid in the second circulation loop can fully absorb heat and completely vaporize when flowing through the heat exchanger, avoiding incomplete vaporization due to insufficient heat transfer temperature difference, which would affect the normal operation of the expander. When the heat source temperature rises, the control board correspondingly increases the speed of the working fluid pump to increase the working fluid flow rate; when the heat source temperature decreases, the control board correspondingly decreases the speed of the working fluid pump to reduce the working fluid flow rate.

[0069] In other words, by precisely controlling the outlet pressure of the working fluid pump to be the saturation pressure corresponding to the heat source temperature minus the temperature margin, the organic working fluid is always kept in the optimal vaporization state in the heat exchanger. This avoids both insufficient vaporization of the working fluid due to excessively high pressure and decreased system efficiency due to excessively low pressure, ensuring that the organic Rankine cycle loop can operate stably and efficiently under different heat source temperature conditions.

[0070] S160, Adjust the load of the expansion generator assembly.

[0071] Specifically, during the operation of the second circulation loop, the control board monitors the current rotational speed of the expansion generator in real time through a speed sensor installed on the shaft of the expansion generator, and compares this actual rotational speed with a preset rotational speed range stored internally. The lower limit of the preset rotational speed range is the minimum rotational speed required to ensure stable operation of the expansion generator. Below this speed, the mechanical efficiency of the expander decreases significantly, and excessive flow resistance of the working fluid may affect the continuous operation of the cycle. The upper limit of the preset rotational speed range is the maximum rotational speed allowed to ensure safe operation of the expansion generator. Above this speed, there is a risk of mechanical overload on the rotating parts, which may cause safety hazards.

[0072] The control board dynamically adjusts the generator load based on the comparison results: when the actual speed is higher than the upper limit of the preset speed range, the control board increases the generator's electromagnetic load (e.g., by increasing the excitation current or connecting a load resistor), increasing the rotational resistance of the expander impeller and thus consuming excess energy to reduce the speed to the preset range; when the actual speed is lower than the lower limit of the preset speed range, the control board decreases the generator's electromagnetic load, reducing the rotational resistance of the expander impeller and thus increasing the speed to the preset range; when the actual speed is within the preset speed range, the control board maintains the generator's current load without adjustment. The essence of this load regulation lies in adjusting the expander's speed by changing the generator's electromagnetic resistance torque, maintaining a dynamic balance between the expander's output mechanical energy and the generator's electromagnetic load, thereby keeping the entire organic Rankine cycle loop in a stable operating state.

[0073] In other words, by monitoring the speed of the expansion generator components in real time and dynamically adjusting the generator load, the speed of the expander is always kept within the preset speed range. This avoids situations where the expander speed is too low due to excessive load, resulting in excessive flow resistance of the working fluid and affecting the normal operation of the cycle. It also avoids situations where the expander speed is too high due to excessive load, resulting in mechanical safety risks. This ensures the safety and stability of the second circulation loop in long-term operation.

[0074] In one embodiment, the steps of acquiring temperature parameters and determining whether the start-up conditions are met, and controlling the start and stop of the second loop based on the determination result, include: Obtain the temperature value of the heat exchanger and the temperature value of the external environment, and calculate the temperature difference between the two; When the temperature difference value is greater than the preset value, the second circulation loop is activated; When the temperature difference is less than or equal to the preset value, the second circulation loop remains in standby mode.

[0075] Specifically, the control board continuously collects the temperature value of the heat exchanger through a first temperature sensor installed on the heat exchanger. This temperature value reflects the condensation temperature (cooling state) or evaporation temperature (heating state) of the refrigerant in the heat exchanger in the first circulation loop. Simultaneously, the control board continuously collects the ambient temperature value through a second temperature sensor installed on the outside of the outdoor unit casing. This temperature value reflects the actual ambient temperature. The control board subtracts the two temperature values ​​collected at the same time to calculate the temperature difference between the heat exchanger temperature and the ambient temperature. This temperature difference represents the portion of the heat exchanger temperature that is higher than the ambient temperature in cooling operation, and the portion of the ambient temperature that is higher than the heat exchanger temperature in heating operation. Regardless of the operating condition, this temperature difference represents the absolute value of the usable temperature difference in the second circulation loop where the organic working fluid can perform work. The control board's internal memory stores a preset starting temperature difference value, ranging from 5 to 10 degrees Celsius. The specific value is determined by the accuracy of the pressure control element in the second circulation loop: when the pressure control element has high accuracy, a smaller preset value, such as 5 degrees Celsius, can be used to allow the second circulation loop to start operating under smaller temperature differences, increasing the frequency and total amount of energy recovery; when the pressure control element has low accuracy, a larger preset value, such as 10 degrees Celsius, must be used to ensure reliable operation of the system after startup without control instability. The control board compares the calculated temperature difference value with the preset value. If the temperature difference value is greater than the preset value, the startup conditions are met; if the temperature difference value is less than or equal to the preset value, the startup conditions are not met.

[0076] When the temperature difference is greater than the preset value, the control board determines that the current temperature difference meets the requirements for effective work of the organic Rankine cycle. It then sends a start signal to the working fluid pump's drive circuit, and the working fluid pump starts operating, driving the organic working fluid to circulate in the second circulation loop. The second circulation loop then starts operating, recovering energy and converting it into electrical energy. When the temperature difference is less than or equal to the preset value, the control board determines that the organic working fluid cannot form a sufficient pressure difference to drive the expansion generator to effectively perform work under the current temperature difference conditions. Forcing a start would not only fail to generate usable electrical energy but would also increase the total energy consumption of the air conditioning system due to the working fluid pump's own power consumption. Therefore, the control board does not send a start signal, the working fluid pump remains stopped, and the second circulation loop is in standby mode.

[0077] After the second circulation loop is in operation, the control board continuously monitors changes in the temperature difference. When the temperature difference subsequently drops below the preset value, it indicates that the operating conditions no longer meet the work requirements. The control board then sends a stop signal to the second circulation loop, executing the shutdown procedure. The working fluid pump stops operating, and the expander gradually stops. Furthermore, when the air conditioning system itself receives a shutdown command, regardless of the temperature difference conditions, the control board also sends a stop signal to the second circulation loop.

[0078] In other words, by using a temperature difference threshold of 5 to 10 degrees Celsius as the start-stop control boundary of the second loop, the energy recovery process is precisely matched with the actual operating conditions of the system. This ensures that the second loop can be put into operation in a timely manner when the conditions for doing work are met to maximize energy recovery, while avoiding energy inversion and unnecessary equipment loss caused by ineffective operation when the temperature difference is insufficient. This achieves precision and energy saving in the start-stop control of the second loop.

[0079] In one embodiment, the step of adjusting the load of the expansion power generation component includes: monitoring the rotational speed of the expansion power generation component, adjusting the load of the expansion power generation component according to the rotational speed, so that the rotational speed of the expansion power generation component is maintained within a preset rotational speed range.

[0080] Specifically, the control board obtains the current rotational speed of the expansion generator assembly in real time through a speed sensor installed on the common shaft of the expansion generator assembly. The speed sensor can be a Hall effect sensor or a photoelectric encoder; its output pulse signal frequency is proportional to the rotational speed of the shaft. The control board calculates the actual rotational speed of the shaft by measuring the frequency of the pulse signal. The control board's internal memory stores a preset speed range, including a lower limit and an upper limit. The lower limit is the minimum speed required to ensure stable and efficient operation of the expansion generator assembly. It is determined based on the following: below this speed, the impeller linear velocity of the expander is too low, the working fluid cannot form effective flow and energy conversion in the impeller channel, the generator's output voltage and frequency are too low to meet the requirements of the rectifier circuit, and the working fluid pump needs to overcome significant flow resistance to drive the working fluid circulation, resulting in a sharp decrease in the overall system efficiency. The upper limit is the highest permissible speed to ensure safe operation of the expansion generator assembly. It is determined based on the following: above this speed, the centrifugal force on the rotating parts exceeds the design safety threshold, the bearing temperature rises sharply, mechanical wear intensifies rapidly, and there is a serious safety risk of impeller breakage or shaft damage. Therefore, controlling the rotational speed within this preset range is a fundamental prerequisite for ensuring system safety and operational efficiency.

[0081] The control board compares the monitored actual speed with the preset speed range in real time. When the actual speed exceeds the upper limit of the preset speed range, it indicates that the current generator load is too low, and the expander outputs excessive mechanical energy, resulting in an excessively high speed. In this case, the control board increases the generator's excitation current through the power management module, increasing the magnetic field strength generated by the generator stator. The electromagnetic resistance torque experienced by the rotor cutting magnetic lines of force during rotation increases accordingly, requiring the expander to output more mechanical energy to overcome this resistance, thus consuming the excess energy and reducing the speed to the normal range. When the actual speed is below the lower limit of the preset speed range, it indicates that the current generator load is too high, and the expander's output mechanical energy is insufficient to drive the generator to maintain a normal speed under the current electromagnetic resistance. In this case, the control board reduces the generator's excitation current through the power management module, reducing the electromagnetic resistance torque, allowing the expander to achieve a higher speed under the same working fluid. When the actual speed is within the preset speed range, the control board maintains the generator's current load parameters without adjustment.

[0082] The core purpose of this load regulation step is to maintain the smooth operation of the generator, expander, and the entire organic Rankine cycle. When the generator load is too high, the expander impeller experiences excessive resistance, resulting in a decrease in speed. This causes back pressure to form at the expander inlet due to poor flow of the working fluid, requiring the working fluid pump to maintain circulation. Excessive flow resistance also affects the normal operation of the cycle. Conversely, when the generator load is too low, the expander impeller experiences insufficient resistance, leading to an increase in speed. This increases the centrifugal stress on the rotating components, potentially causing mechanical safety risks. Through the aforementioned load regulation, the speed of the expander-generator assembly is precisely controlled within a preset speed range.

[0083] In other words, by monitoring the expander speed in real time and dynamically adjusting the generator load, the expansion power generation component can maintain a stable speed under different heat source temperatures, different working fluid flow rates, and different operating conditions. This ensures that the energy conversion efficiency is always at a high level, effectively avoids circulation obstruction caused by excessively low speed and safety risks caused by excessively high speed, and improves the adaptability and long-term operational reliability of the second circulation loop under varying operating conditions.

[0084] In one specific embodiment, the step of adjusting the load of the expansion power generation component further includes: When the rotational speed of the expansion power generation component exceeds the upper limit of the preset rotational speed range, the load on the expansion power generation component is increased; When the rotational speed of the expansion power generation component is lower than the lower limit of the preset rotational speed range, the load on the expansion power generation component is reduced; When the rotational speed of the expansion power generation component is within the preset rotational speed range, the current load of the expansion power generation component is maintained.

[0085] Specifically, the control board continuously receives the speed signal of the expansion generator from the speed sensor, compares the actual speed value represented by the signal with the preset speed range stored internally in real time, and performs corresponding load adjustment operations based on the comparison results.

[0086] The first adjustment method: When the control board determines that the current speed of the expander generator is higher than the upper limit of the preset speed range, the control board executes an operation to increase the generator load. Specifically, the control board sends a load increase command to the power management module. The power management module increases the generator's excitation current according to this command, thereby strengthening the magnetic field generated by the generator stator coils. When the generator rotor rotates in this enhanced magnetic field, it experiences a greater electromagnetic resistance torque. This resistance torque is transmitted to the expander impeller through the shared shaft, increasing the rotational resistance felt by the impeller. This consumes the excess mechanical energy output by the expander and gradually reduces the speed. When the speed drops to within the preset speed range, the control board stops the load increase operation and maintains the current excitation current value. In other words, by increasing the generator's electromagnetic resistance torque to consume the excess energy output by the expander, the speed is safely reduced to the preset range, effectively preventing mechanical damage and safety accidents caused by excessive speed, while converting excess energy into electrical energy output instead of wasting it.

[0087] The second adjustment method: When the control board determines that the current speed of the expander generator is lower than the lower limit of the preset speed range, the control board performs a load reduction operation on the generator. Specifically, the control board sends a load reduction command to the power management module. The power management module, based on this command, reduces the generator's excitation current, weakening the magnetic field strength generated by the generator stator coils. The electromagnetic resistance torque experienced by the generator rotor rotating in this weakened magnetic field decreases accordingly. This reduction in resistance torque is transmitted to the expander impeller through the shared shaft, reducing the rotational resistance felt by the impeller. Thus, the expander can achieve a higher speed under the same working fluid driving force. When the speed increases to within the preset speed range, the control board stops the load reduction operation and maintains the current excitation current value. In other words, by reducing the generator's electromagnetic resistance torque to release the expander's output capacity and increase the speed to the preset range, the obstruction of circulation flow and the decrease in power generation efficiency caused by excessively low speed are effectively prevented, ensuring the working fluid flow power required for the normal operation of the second circulation loop.

[0088] The third adjustment method: When the control board determines that the current speed of the expansion generator is within the preset speed range, the control board maintains the current load of the generator. Specifically, the control board does not send any adjustment commands to the power management module, the generator's excitation current remains unchanged, the electromagnetic resistance torque remains unchanged, and the speed of the expansion generator continues to operate stably under the current conditions. In other words, when the system is in a balanced state, the existing parameters are maintained unchanged to avoid unnecessary adjustments that could cause system oscillations, allowing the expansion generator to continue energy conversion in a stable state.

[0089] In this process, the power module rectifies and converts the AC power generated by the generator into stable DC power during generator load control. This DC power is then combined with the DC power input from the external power source on the busbar to supply power to the air conditioning system's compressor inverter, axial fan motor driver, and working fluid pump drive circuit, thereby reducing the air conditioning system's consumption of external grid power. This rectification and combination operation is performed synchronously during load regulation to ensure effective utilization of the generator's output. Through the real-time coordination of these three regulation methods, the speed of the expansion generator assembly is precisely maintained within a stable range centered on a preset speed range.

[0090] Therefore, by precisely switching between the three operating modes of increasing load, decreasing load, and maintaining load, the speed of the expansion generator component is always kept within a safe and efficient preset range under different operating conditions. At the same time, the generated energy is rectified and supplied to the air conditioning system itself, forming a complete closed loop from energy recovery, conversion to utilization, effectively reducing the air conditioning system's dependence on external power and lowering overall energy consumption.

[0091] The aforementioned air conditioning control method with dual independent circulation loops identifies the operating status of the air conditioning system and controls the switching component to switch operating modes based on this status. This allows the second circulation loop to obtain the corresponding heat or cold source in cooling and heating modes, respectively. Furthermore, the starting conditions are determined based on the temperature difference between the heat exchanger and the external environment, and the start and stop of the second circulation loop are controlled. This ensures that the organic Rankine cycle only operates when the temperature difference meets the work-doing conditions to avoid inefficient operation. It also maintains the loop in a stable and efficient operating range through working fluid pump operation control and expansion generator load adjustment. The above control logic forms a complete closed loop from operating condition identification, mode switching, temperature difference determination to component adjustment. The organic Rankine cycle can stably and efficiently recover waste heat or waste cold and convert it into electrical energy under all air conditioning operating conditions. At the same time, it effectively prevents safety risks caused by excessively high or low speed of the expansion generator, improving the safety and reliability of system operation. Thus, it reduces the overall energy consumption of the air conditioning system while ensuring operational stability, making it an energy-saving air conditioning device.

[0092] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present technical solution are within the protection scope of the present invention.

Claims

1. An air conditioning system with dual independent circulation loops, characterized in that, include: The first circulation loop is a vapor compression circulation loop, which is used to realize the cooling or heating function of the air conditioning system. The second circulation loop, which is an organic Rankine loop, is used to recover the heat or cold generated during the operation of the first circulation loop and convert it into electrical energy. A switching component is used to switch the operating modes of the first circulation loop and the second circulation loop between a cooling operating state and a heating operating state. The first and second circulation loops are independent of each other, and heat exchange occurs between the two loops through a heat exchanger. In the cooling operation mode, the heat exchanger serves as the heat source for the second circulation loop; In heating mode, the heat exchanger serves as the cold source for the second circulation loop.

2. The air conditioning system with dual independent circulation loops according to claim 1, characterized in that, The switching assembly includes a first four-way valve, a second four-way valve, and a third four-way valve. The switching between cooling and heating modes is achieved by controlling the direction of the first four-way valve, the second four-way valve, and the third four-way valve.

3. The air conditioning system with dual independent circulation loops according to claim 2, characterized in that, The first circulation loop also includes a compressor, an indoor unit heat exchanger, and an electronic expansion valve. The heat exchanger, the electronic expansion valve, the indoor unit heat exchanger, the compressor, and the first four-way valve are connected by pipelines to form a circulation loop.

4. The air conditioning system with dual independent circulation loops according to claim 2, characterized in that, The second circulation loop also includes a working fluid pump, an outdoor unit heat exchanger, and an expansion generator assembly. The heat exchanger, the third four-way valve, the expansion generator assembly, the outdoor unit heat exchanger, the second four-way valve, and the working fluid pump are connected by pipelines to form a circulation loop.

5. The air conditioning system with dual independent circulation loops according to claim 4, characterized in that, The expansion power generation assembly includes an expander and a generator. The generator and the expander share a shaft, and the expander drives the generator to rotate to generate electrical energy.

6. The air conditioning system with dual independent circulation loops according to claim 1, characterized in that, The first circulating loop uses a first working medium, and the second circulating loop uses a second working medium. The first working medium and the second working medium are different types of working mediums.

7. An air conditioning control method with dual independent circulation loops, applied to an air conditioning system with dual independent circulation loops as described in any one of claims 1-6, characterized in that, The air conditioning control method with dual independent circulation loops includes: Identify the operating status of the air conditioning system; The mode is switched according to the working status control switching component; Obtain temperature parameters and determine whether the startup conditions are met; The start and stop of the second loop are controlled based on the judgment result; Control the operation of the working fluid pump; Adjust the load on the expansion generator components.

8. The air conditioning control method with dual independent circulation loops according to claim 7, characterized in that, The steps of acquiring temperature parameters and determining whether the start-up conditions are met, and controlling the start and stop of the second loop based on the determination result, include: Obtain the temperature value of the heat exchanger and the temperature value of the external environment, and calculate the temperature difference between the two; When the temperature difference value is greater than the preset value, the second circulation loop is activated; When the temperature difference is less than or equal to the preset value, the second circulation loop remains in standby mode.

9. The air conditioning control method with dual independent circulation loops according to claim 7, characterized in that, The step of adjusting the load of the expansion power generation component includes: monitoring the rotational speed of the expansion power generation component, adjusting the load of the expansion power generation component according to the rotational speed, so that the rotational speed of the expansion power generation component is maintained within a preset rotational speed range.

10. The air conditioning control method with dual independent circulation loops according to claim 9, characterized in that, The step of adjusting the load of the expansion power generation component further includes: When the rotational speed of the expansion power generation component exceeds the upper limit of the preset rotational speed range, the load on the expansion power generation component is increased; When the rotational speed of the expansion power generation component is lower than the lower limit of the preset rotational speed range, the load on the expansion power generation component is reduced; When the rotational speed of the expansion power generation component is within the preset rotational speed range, the current load of the expansion power generation component is maintained.

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