Heat recovery heat pump system and control method

Abstract

The present invention discloses a heat recovery heat pump system and a control method. The heat recovery heat pump system includes: a compressor and a heat exchanger combination having three heat exchangers. The second end of the first heat exchanger is connected to the second end of the second heat exchanger through a first valve. The first end of the first heat exchanger is connected to the second end of the third heat exchanger through a second valve. The first ends of the second heat exchangers are both connected to the second end of the third heat exchanger through a third valve. The second end of the first heat exchanger is connected to the first end of the third heat exchanger through a fourth valve. The second end of the first heat exchanger is connected to the second end of the third heat exchanger through a first throttling branch. The second end of the second heat exchanger is connected to the second end of the first heat exchanger through a second throttling branch. The second end of the second heat exchanger is connected to the second end of the third heat exchanger through a third throttling branch. By optimizing the pipeline design of the heat exchanger, the present invention utilizes the idle heat exchanger to dynamically adjust the amount of refrigerant participating in the cycle in the loop, improves the heat exchange efficiency and simplifies the system structure.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to a heat recovery heat pump system capable of recycling refrigerant by using a spare heat exchanger and a control method therefor. Background Art

[0002] With the continuous growth of global energy demand and the increasingly strict environmental protection requirements, the importance of heat recovery technology in heating, ventilation, air conditioning, refrigeration and heat pump systems has become increasingly prominent. In traditional systems, as the core medium for heat transfer, a large amount of waste heat carried by the refrigerant during its circulation process is often not fully utilized, resulting in significant energy waste. Although various heat recovery solutions have been developed in the prior art, there is generally a key defect: the system cannot dynamically adjust the refrigerant amount in the circulation loop according to the actual working conditions, resulting in unstable heat exchange efficiency, which severely restricts the heat recovery effect.

[0003] Existing heat recovery systems usually adopt a heat exchanger design with a fixed structure, and their working process relies on the forced convective heat transfer of the refrigerant in the established flow channels. For example, during the condensation stage of an air conditioning system, when the high-temperature and high-pressure gaseous refrigerant flows through the heat exchanger, it transfers heat to the secondary fluid (such as water or air). However, this fixed-flow design has obvious drawbacks: when the system load changes, the refrigerant flow rate and the phase change state (such as superheat, saturation or subcooling) change, but the heat exchanger cannot adaptively adjust the refrigerant circulation amount, resulting in a large fluctuation in the heat exchange efficiency. Especially under partial load conditions, excessive refrigerant stays in the heat exchanger, not only reducing the effective heat exchange area, but also increasing the flow resistance, causing a significant drop in the system energy efficiency.

[0004] In order to make the refrigerant amount in the heat pump system more appropriate, the prior art often needs to add auxiliary equipment. For example, a liquid storage branch with a liquid storage device is installed in the heat pump system, and the refrigerant amount participating in the cycle is adjusted by controlling the liquid inlet amount and the liquid outlet amount of the liquid storage device. However, this design will greatly increase the production cost and maintenance difficulty of the heat pump system.

[0005] Therefore, how to design a heat recovery heat pump system and a control method that can utilize a spare heat exchanger to adjust the refrigerant amount is an urgent technical problem in the industry. Summary of the Invention

[0006] In order to solve the above-mentioned defects existing in the prior art, the present invention provides a heat exchanger cleaning system, a cleaning method and an air conditioning unit. By optimizing the pipeline design of the heat exchanger, a spare heat exchanger is used to dynamically adjust the refrigerant amount participating in the cycle in the loop, while improving the heat exchange efficiency, reducing the number of system devices, simplifying the system structure and reducing the cost.

[0007] The technical solution adopted by the present invention is to design a heat recovery heat pump system, including: a compressor and a heat exchanger combination, and the heat exchanger combination includes: three heat exchangers;

[0008] The second end of the first heat exchanger is connected to the second end of the second heat exchanger through a first valve, the first end of the first heat exchanger is connected to the second end of the third heat exchanger through a second valve, the first ends of the second heat exchangers are both connected to the second end of the third heat exchanger through a third valve, and the second end of the first heat exchanger is connected to the first end of the third heat exchanger through a fourth valve;

[0009] The second end of the first heat exchanger is connected to the second end of the third heat exchanger through a first throttling branch, the second end of the second heat exchanger is connected to the second end of the first heat exchanger through a second throttling branch, and the second end of the second heat exchanger is connected to the second end of the third heat exchanger through a third throttling branch;

[0010] Wherein, the exhaust side of the compressor can be switched to connect to the first end of any one of the heat exchangers. When two heat exchangers are connected to the compressor to form a main circulation loop, the remaining one heat exchanger can be used as a standby heat exchanger for storing refrigerant.

[0011] Furthermore, the first heat exchanger is an air-conditioning water heat exchanger, the second heat exchanger is a hot water heat exchanger, the third heat exchanger is an external heat exchanger, and the operating modes of the heat pump system include at least one of a cooling mode, a heating mode, a hot water supply mode, a cooling plus hot water supply mode, and a heating plus hot water supply mode.

[0012] Furthermore, when the heat pump system operates in the cooling mode, the first heat exchanger serves as an evaporator, the third heat exchanger serves as a condenser, and the second heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the first valve and the third valve;

[0013] and / or when the heat pump system operates in the heating mode, the first heat exchanger serves as a condenser, the third heat exchanger serves as an evaporator, and the second heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the first valve and the third valve;

[0014] and / or when the heat pump system operates in the hot water supply mode, the second heat exchanger serves as a condenser, the third heat exchanger serves as an evaporator, and the first heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the first valve and the second valve;

[0015] and / or when the heat pump system operates in the cooling plus hot water supply mode, the first heat exchanger serves as an evaporator, the second heat exchanger serves as a condenser, the third heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the third throttling branch and the fourth valve;

[0016] and / or when the heat pump system operates in the heating plus hot water supply mode, the first heat exchanger or both of the second heat exchangers serve as condensers, the third heat exchanger serves as an evaporator, and the remaining one heat exchanger serves as a standby heat exchanger.

[0017] Further, a first throttle valve and a second throttle valve are installed in the first refrigerant flow branch, and the second throttle valve is connected between the first throttle valve and the second end of the first heat exchanger; the second end of the second heat exchanger is connected between the first throttle valve and the second throttle valve through a control valve.

[0018] Wherein, the control valve and the second throttle valve form a second throttle branch, and the control valve and the first throttle valve form a third throttle branch.

[0019] Further, the compressor is connected to the heat exchanger combination through two four-way valves; the D end of the first four-way valve is connected to the exhaust side of the compressor, the E end is connected to the first end of the first heat exchanger, the S end is connected to the suction side of the compressor, and the C end is connected to the D end of the second four-way valve; the C end of the second four-way valve is connected to the first end of the third heat exchanger, the E end is connected to the first end of the second heat exchanger, and the S end is connected to the suction side of the compressor.

[0020] Further, the standby heat exchanger is configured with an auxiliary heating device for raising the temperature of the refrigerant. When the auxiliary heating device is controlled to be turned on, it provides heat to promote the refrigerant to flow out of the standby heat exchanger.

[0021] The present invention also proposes a control method for the heat recovery heat pump system. This control method is applied to the above-mentioned heat recovery heat pump system and includes:

[0022] Obtain the working mode and actual operating parameters of the heat pump system;

[0023] Analyze the load demand level according to the working mode and actual operating parameters;

[0024] Adjust the working states of the compressor and the heat exchanger combination according to the load demand level.

[0025] Further, analyzing the load demand level according to the working mode and actual operating parameters includes:

[0026] Establish a control relationship between the working mode, the load demand level and the parameter conditions in advance;

[0027] Obtain the corresponding load demand level from the control relationship according to the working mode and actual operating parameters.

[0028] Further, the load demand level includes high load, medium load and low load. Adjusting the working states of the compressor and the heat exchanger combination according to the load demand level includes:

[0029] If the heat pump system is in a high load state, reduce the liquid storage volume of the standby heat exchanger, increase the operating frequency of the compressor to the set high frequency range, and increase the refrigerant circulation flow rate in the main circulation loop to the set high volume range;

[0030] If the heat pump system is under medium load, adjust the liquid output of the idle heat exchanger to keep the operating frequency of the compressor within the set moderate range and keep the refrigerant circulation flow rate in the main circulation loop within the set medium flow rate range;

[0031] If the heat pump system is under low load, increase the liquid storage volume of the idle heat exchanger, reduce the operating frequency of the compressor to the set low frequency range, and reduce the refrigerant circulation flow rate in the main circulation loop to the set low flow rate range.

[0032] Furthermore, adjusting the working states of the compressor and heat exchanger combination according to the load demand level further includes:

[0033] When reducing the liquid storage volume of the idle heat exchanger, detect the heat exchange medium temperature and the output refrigerant flow rate of the idle heat exchanger;

[0034] If the heat exchange medium temperature is lower than the set lower limit temperature and the output refrigerant flow rate is lower than the set lower limit flow rate, turn on the auxiliary heating device to provide heat to promote the refrigerant to flow out of the idle heat exchanger;

[0035] And / or if the heat exchange medium temperature is higher than the set upper limit temperature and the output refrigerant flow rate is higher than the set upper limit flow rate, turn off the auxiliary heating device;

[0036] Wherein, the heat exchange medium temperature is the temperature of the heat exchange medium that exchanges heat with the refrigerant stored in the idle heat exchanger.

[0037] Furthermore, the heat pump system can operate in a composite working mode with two supply functions, and the composite working mode is configured with the priorities of two supply functions;

[0038] The control method further includes:

[0039] After obtaining the working mode and actual operating parameters of the heat pump system, determine whether the working mode is a composite working mode;

[0040] If so, select the supply function with a higher priority and its actual operating parameters to analyze the load demand level, and adjust the working states of the compressor and heat exchanger combination according to the load demand level;

[0041] Wherein, the priority of the supply function is set by the user and / or default setting.

[0042] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0043] 1. Optimize the pipeline connection structure between the three heat exchangers - the first heat exchanger to the third heat exchanger, and use the idle heat exchanger to dynamically adjust the amount of refrigerant participating in the cycle in the loop. Without relying on additional liquid storage components, while improving the heat exchange efficiency, reduce the number of system devices, simplify the system structure and reduce costs;

[0044] 2. The standby heat exchanger is equipped with an auxiliary heating device. When the temperature of the standby heat exchanger is too low, the auxiliary heating device can be turned on to provide heat, prompting the refrigerant to flow out of the standby heat exchanger, so that the amount of refrigerant in the main circulation loop can quickly match the current working condition, greatly improving the heat exchange performance of the heat pump system and optimizing the user experience.

[0045] 3. The heat pump system can dynamically adjust the working states of the compressor and the heat exchanger combination according to different working modes and actual loads, enhancing the system flexibility, ensuring that the amount of refrigerant in the main circulation loop is appropriate, and meeting the user requirements. Brief Description of the Drawings

[0046] The present invention will be described in detail below in conjunction with the embodiments and the drawings, where:

[0047] Figure 1 is a connection schematic diagram of the heat pump system of the present invention;

[0048] Figure 2 is a schematic diagram of the refrigerant flow direction in the cooling mode of the present invention;

[0049] Figure 3 is a schematic diagram of the refrigerant flow direction in the heating mode of the present invention;

[0050] Figure 4 is a schematic diagram of the refrigerant flow direction in the hot water supply mode of the present invention;

[0051] Figure 5 is a schematic diagram of the refrigerant flow direction in the cooling plus hot water supply mode of the present invention;

[0052] Figure 6 is a schematic diagram of the operating states in different modes of the present invention;

[0053] Figure 7 is a logic schematic diagram of the control method of the present invention;

[0054] Figure 8 is a schematic diagram of the control scheme for different loads of the present invention;

[0055] Brief Description of the Drawings: 1. Compressor; 2. First heat exchanger; 3. Second heat exchanger; 4. Third heat exchanger; 5. First valve; 6. Second valve; 7. Third valve; 8. Fourth valve; 9. Control valve; 10. First throttle valve; 11. Second throttle valve; 12. First four-way valve; 13. Second four-way valve; 14. Gas-liquid separator. Detailed Embodiments

[0056] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the drawings and the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0057] As shown Figure 1 in the figure, the heat recovery heat pump system proposed by the present invention includes: a compressor 1 and a heat exchanger combination. The heat exchanger combination is connected between the exhaust side and the suction side of the compressor 1. The heat exchanger combination includes three heat exchangers, namely a first heat exchanger 2, a second heat exchanger 3, and a third heat exchanger 4. For ease of understanding, the first end and the second end of each heat exchanger have been marked on the connection schematic diagram of the heat pump system. The first end is "①" and the second end is "②".

[0058] The second end of the first heat exchanger 2 is connected to the second end of the second heat exchanger 3 through a first valve 5. The first end of the first heat exchanger 2 is connected to the second end of the third heat exchanger 4 through a second valve 6. The first end of the second heat exchanger 3 is connected to the second end of the third heat exchanger 4 through a third valve 7. The second end of the first heat exchanger 2 is connected to the first end of the third heat exchanger 4 through a fourth valve 8.

[0059] The second end of the first heat exchanger 2 is connected to the second end of the third heat exchanger 4 through a first throttling branch. The second end of the second heat exchanger 3 is connected to the second end of the first heat exchanger 2 through a second throttling branch. The second end of the second heat exchanger 3 is connected to the second end of the third heat exchanger 4 through a third throttling branch.

[0060] Among them, the exhaust side of the compressor 1 can be switched to connect to the first end of any heat exchanger. When the first end of a certain heat exchanger is connected to the exhaust side of the compressor 1, this heat exchanger serves as a condenser. One of the other two heat exchangers can be selected as an evaporator, and the other heat exchanger serves as an idle heat exchanger for storing refrigerant. The condenser, the evaporator, and the compressor 1 are connected to form a main circulation loop. The idle heat exchanger is connected to the main circulation loop to form a refrigerant recovery branch. When the valve component on the inlet side of the idle heat exchanger is opened, part of the refrigerant is stored in the idle heat exchanger. When the valve component on the outlet side of the idle heat exchanger is opened, the refrigerant flows out of the idle heat exchanger and participates in the cycle again.

[0061] For ease of understanding, some common situations are taken as examples, such as Figure 2 shown in the figure. When the first heat exchanger 2 serves as an evaporator, the third heat exchanger 4 serves as a condenser, and the second heat exchanger 3 serves as an idle heat exchanger, the exhaust side of the compressor 1 is connected to the first end of the third heat exchanger 4. The flow direction of the main circulation loop is compressor 1 → third heat exchanger 4 → first throttling branch → first heat exchanger 2 → return to compressor 1. The flow direction of the refrigerant recovery branch is compressor 1 → third heat exchanger 4 → second heat exchanger 3 (the third valve 7 adjusts the flow rate on the inlet side of the second heat exchanger 3, and the first valve 5 adjusts the flow rate on the outlet side of the second heat exchanger 3) → first heat exchanger 2 → return to compressor 1.

[0062] As Figure 3As shown, when the first heat exchanger 2 serves as a condenser, the third heat exchanger 4 serves as an evaporator, and the second heat exchanger 3 serves as a standby heat exchanger, the exhaust side of the compressor 1 is connected to the first end of the first heat exchanger 2. The flow direction of the main circulation loop is: compressor 1 → first heat exchanger 2 → first throttling branch → third heat exchanger 4 → return to compressor 1. The flow direction of the refrigerant recovery branch is: compressor 1 → first heat exchanger 2 → second heat exchanger 3 (the first valve 5 regulates the flow rate on the inlet side of the second heat exchanger 3, and the third valve 7 regulates the flow rate on the outlet side of the second heat exchanger 3) → third heat exchanger 4 → return to compressor 1.

[0063] As Figure 4 shown, when the second heat exchanger 3 serves as a condenser, the third heat exchanger 4 serves as an evaporator, and the first heat exchanger 2 serves as a standby heat exchanger, the exhaust side of the compressor 1 is connected to the first end of the second heat exchanger 3. The flow direction of the main circulation loop is: compressor 1 → second heat exchanger 3 → third throttling branch → first heat exchanger 2 → return to compressor 1. The flow direction of the refrigerant recovery branch is: compressor 1 → second heat exchanger 3 → first heat exchanger 2 (the first valve 5 regulates the flow rate on the inlet side of the first heat exchanger 2, and the second valve 6 regulates the flow rate on the outlet side of the first heat exchanger 2) → third heat exchanger 4 → return to compressor 1.

[0064] As Figure 5 shown, when the second heat exchanger 3 serves as a condenser, the first heat exchanger 2 serves as an evaporator, and the third heat exchanger 4 serves as a standby heat exchanger, the exhaust side of the compressor 1 is connected to the first end of the second heat exchanger 3. The flow direction of the main circulation loop is: compressor 1 → second heat exchanger 3 → second throttling branch → first heat exchanger 2 → return to compressor 1. The flow direction of the refrigerant recovery branch is: compressor 1 → second heat exchanger 3 → third heat exchanger 4 (the third throttling branch regulates the flow rate on the inlet side of the third heat exchanger 4, and the fourth valve 8 regulates the flow rate on the outlet side of the third heat exchanger 4) → first heat exchanger 2 → return to compressor 1.

[0065] The present invention optimizes the pipeline connection structure between the first heat exchanger 2 and the third heat exchanger 4. When two heat exchangers are connected to the compressor 1 to form a main circulation loop, the remaining one heat exchanger can serve as a standby heat exchanger for storing refrigerant. By using the standby heat exchanger to dynamically adjust the amount of refrigerant participating in the circulation in the loop, without the need to rely on additional liquid storage components, while improving the heat exchange efficiency, the number of system equipment is reduced, the system structure is simplified, and the cost is lowered.

[0066] In some preferred embodiments of the present invention, the first heat exchanger 2 is an air-conditioning water heat exchanger, and a plate heat exchanger is commonly used for the air-conditioning water heat exchanger. The second heat exchanger 3 is a hot water heat exchanger, and a shell-and-tube heat exchanger is commonly used for the hot water heat exchanger. The third heat exchanger 4 is an external heat exchanger, and a finned heat exchanger equipped with a fan is commonly used for the external heat exchanger. When the finned heat exchanger is used as a standby heat exchanger, the fan of the finned heat exchanger is turned off. When the finned heat exchanger participates in the refrigerant circulation of the main circulation loop, the fan of the finned heat exchanger is turned on. The working modes of the heat pump system include at least one of a cooling mode, a heating mode, a hot water supply mode, a cooling plus hot water supply mode, and a heating plus hot water supply mode.

[0067] The heat pump system works in coordination with three heat exchangers, and can flexibly switch operating modes under different working conditions to maximize the recovery of waste heat. For example, in the cooling mode, the refrigerant absorbs heat in the evaporator (air-conditioning water heat exchanger) to achieve cooling; in the heating mode, the high-temperature refrigerant discharged by the compressor 1 releases heat in the condenser (air-conditioning water heat exchanger) to achieve heating; in the hot water supply mode, the high-temperature refrigerant discharged by the compressor 1 is used to heat domestic water in the hot water heat exchanger to improve the hot water supply efficiency; in the combined working mode (cooling + hot water supply / heating + hot water supply), the refrigerant heat is recovered to heat domestic hot water / for heating, realizing cascade utilization of energy and improving the energy efficiency of the heat pump system.

[0068] As Figure 6 shown, specifically, when the heat pump system operates in the cooling mode, the first heat exchanger 2 serves as the evaporator, the third heat exchanger 4 serves as the condenser, and the second heat exchanger 3 serves as the standby heat exchanger, and the refrigerant storage state is adjusted by the first valve 5 and the third valve 7;

[0069] and / or when the heat pump system operates in the heating mode, the first heat exchanger 2 serves as the condenser, the third heat exchanger 4 serves as the evaporator, and the second heat exchanger 3 serves as the standby heat exchanger, and the refrigerant storage state is adjusted by the first valve 5 and the third valve 7;

[0070] and / or when the heat pump system operates in the hot water supply mode, the second heat exchanger 3 serves as the condenser, the third heat exchanger 4 serves as the evaporator, and the first heat exchanger 2 serves as the standby heat exchanger, and the refrigerant storage state is adjusted by the first valve 5 and the second valve 6;

[0071] and / or when the heat pump system operates in the cooling plus hot water supply mode, the first heat exchanger 2 serves as the evaporator, the second heat exchanger 3 serves as the condenser, the third heat exchanger 4 serves as the standby heat exchanger, and the refrigerant storage state is adjusted by the third throttling branch and the fourth valve 8.

[0072] And / or when the heat pump system operates in the heating plus domestic hot water supply mode, either the first heat exchanger 2 or the second heat exchanger 3 serves as the condenser, the third heat exchanger 4 serves as the evaporator, and the remaining heat exchanger serves as the idle heat exchanger. The heat pump system usually defaults to giving priority to domestic hot water, and users can also independently set the priority of air conditioning heating and domestic hot water. If domestic hot water is prioritized, it is the same as the domestic hot water supply mode, where the second heat exchanger 3 serves as the condenser, the third heat exchanger 4 serves as the evaporator, and the first heat exchanger 2 serves as the idle heat exchanger, and the refrigerant storage state is adjusted through the first valve 5 and the second valve 6; if air conditioning heating is prioritized, it is the same as the heating mode, where the first heat exchanger 2 serves as the condenser, the third heat exchanger 4 serves as the evaporator, and the second heat exchanger 3 serves as the idle heat exchanger, and the refrigerant storage state is adjusted through the first valve 5 and the third valve 7. In this mode, after the current function reaches the shutdown condition, it is judged whether the other function meets the startup condition. If so, the function starts and runs. For example, by default, domestic hot water is prioritized. After the domestic hot water supply function reaches the shutdown condition, it is judged whether the heating function meets the startup condition. If so, the heating function starts and runs until the shutdown condition of the heating function is reached.

[0073] In this design, in the single-function mode (cooling / heating / domestic hot water supply) and the combined-function mode (cooling plus domestic hot water supply / heating plus domestic hot water supply), the unnecessary heat exchanger is set as the idle heat exchanger, and the idle heat exchanger is isolated from the main circulation loop through valve components (the first valve, the second valve, the third valve, the fourth valve, etc.), so that the refrigerant flows concentratedly to the functional heat exchanger, and the energy storage function of the idle heat exchanger is used to store the excess refrigerant amount in the main circulation loop or release the refrigerant amount into the main circulation loop, enabling the flexible distribution of the refrigerant in the main circulation loop according to demand and improving the operating energy efficiency of the heat pump system.

[0074] As Figure 1 shown, on the basis of optimizing the heat exchanger combination pipeline, in order to make the pipeline structure of the heat pump system more concise, a first throttling branch is installed with a first throttling valve 10 and a second throttling valve 11. The second throttling valve 11 is connected between the first throttling valve 10 and the second end of the first heat exchanger 2. The second end of the second heat exchanger 3 is connected between the first throttling valve 10 and the second throttling valve 11 through a control valve 9, that is, one end of the control valve 9 is connected to the second end of the second heat exchanger 3, and the other end of the control valve 9 is connected to the pipeline between the first throttling valve 10 and the second throttling valve 11. The control valve 9 and the second throttling valve 11 form the second throttling branch, and the control valve 9 and the first throttling valve 10 form the third throttling branch. This design realizes the coordinated control of the three throttling branches, independently controls the refrigerant distribution states of the three heat exchangers through the first throttling valve 10, the second throttling valve 11, and the control valve 9, and realizes the high-precision dynamic adjustment of the refrigerant flow rate and flow direction while maintaining the pipeline simplicity, which is particularly suitable for application scenarios with diverse working modes.

[0075] As Figure 1As shown, in a preferred embodiment of the present invention, the working mode of the heat pump system includes the five working modes mentioned above. In order to achieve more accurate and reliable switching to different working modes, the compressor 1 is connected to the heat exchanger combination through two four-way valves, the D end of the first four-way valve 12 is connected to the exhaust side of the compressor 1, the E end is connected to the first end of the first heat exchanger 2, the S end is connected to the suction side of the compressor 1, and the C end is connected to the D end of the second four-way valve 13. The C end of the second four-way valve 13 is connected to the first end of the third heat exchanger 4, the E end is connected to the first end of the second heat exchanger 3, and the S end is connected to the suction side of the compressor 1.

[0076] The following details the refrigerant flow direction in different working modes.

[0077] like Figure 2 As shown, when the heat pump system operates in cooling mode, end D of first four-way valve 12 connects to end C, end E connects to end S, and end D of second four-way valve 13 connects to end C, end E connects to end S. The main circulation loop flows from compressor 1 to third heat exchanger 4, first throttle valve 10, second throttle valve 11, first heat exchanger 2, and back to compressor 1. In cooling mode, opening third valve 7 can divert some refrigerant to be stored in second heat exchanger 3, with first valve 5 determining whether to discharge the refrigerant.

[0078] like Figure 3 As shown, when the heat pump system operates in heating mode, end D of first four-way valve 12 connects to end E, end C connects to end S, and end D of second four-way valve 13 connects to end C, and end E connects to end S. The main circulation loop flows from compressor 1 to first heat exchanger 2, second throttle valve 11, first throttle valve 10, third heat exchanger 4, and back to compressor 1. In heating mode, opening first valve 5 diverts some refrigerant to be stored in second heat exchanger 3, with third valve 7 determining whether to discharge the refrigerant.

[0079] like Figure 4 As shown, when the heat pump system operates in hot water supply mode, end D of first four-way valve 12 connects to end C, end E connects to end S, and end D of second four-way valve 13 connects to end E, end C connects to end S. The main circulation loop flows from compressor 1 to second heat exchanger 3 to control valve 9 to first throttle valve 10 to third heat exchanger 4, and then back to compressor 1. In hot water supply mode, second throttle valve 11 is closed, and opening first valve 5 diverts some refrigerant to be stored in first heat exchanger 2. Second valve 6 determines whether to discharge the refrigerant.

[0080] like Figure 5As shown, when the heat pump system operates in the cooling plus domestic hot water supply mode, the D end of the first four-way valve 12 is connected to the C end, the E end is connected to the S end, the D end of the second four-way valve 13 is connected to the E end, and the C end is connected to the S end. The main circulation loop flow direction is compressor 1 → second heat exchanger 3 → control valve 9 → second throttle valve 11 → first heat exchanger 2 → back to compressor 1. In the cooling plus domestic hot water supply mode, opening the first throttle valve 10 can divert part of the refrigerant to be stored in the third heat exchanger 4, and the fourth valve 8 determines whether to discharge the refrigerant.

[0081] When the heat pump system operates in the heating plus domestic hot water supply mode, the heat pump system usually defaults to giving priority to domestic hot water, and the user can also independently set the priority of air conditioning heating and domestic hot water. If domestic hot water is prioritized, the states of the four-way valves and the refrigerant flow direction are the same as those in the domestic hot water supply mode. If air conditioning heating is prioritized, the states of the four-way valves and the refrigerant flow direction are the same as those in the heating mode.

[0082] In a preferred embodiment of the present invention, the idle heat exchanger is further configured with an auxiliary heating device for raising the temperature of the refrigerant. The auxiliary heating device can be an electric heater or a heating branch that draws high-temperature refrigerant from pipelines such as the exhaust side of the compressor, etc. The present invention does not make special restrictions on the specific form of the auxiliary heating device. The function of this design is that when the temperature of the idle heat exchanger is too low, heat can be provided by turning on the auxiliary heating device to promote the refrigerant to flow out of the idle heat exchanger, so that the amount of refrigerant in the main circulation loop can quickly match the current working conditions, greatly improving the heat exchange performance of the heat pump system and optimizing the user experience.

[0083] As Figure 7 shown, the present invention also proposes a control method for the heat recovery heat pump system. This control method is applied to the above-mentioned heat recovery heat pump system and includes:

[0084] Obtain the working mode and actual operating parameters of the heat pump system;

[0085] Analyze the load demand level according to the working mode and actual operating parameters;

[0086] Adjust the working states of the compressor and heat exchanger combination according to the load demand level.

[0087] The actual operating parameters collected by this design play a key role in control. Through the dynamic adjustment and feedback mechanism, the heat pump system can optimize the refrigerant outflow state according to real-time data to adapt to different working modes and working condition requirements.

[0088] In some feasible embodiments of the present invention, analyzing the load demand level according to the working mode and actual operating parameters includes:

[0089] Pre-establish the correspondence relationship between the working mode, load demand level and parameter conditions;

[0090] Obtain the corresponding load demand level from the control relationship according to the working mode and actual operating parameters.

[0091] Taking the refrigeration mode as an example, the parameter conditions for high load are that the deviation between the indoor temperature and the set value is large (indoor temperature > set value + 5°C) or the outdoor ambient temperature is high (outdoor ambient temperature > 30°C). The parameter conditions for medium load are that the deviation between the indoor temperature and the set value is moderate (set value + 5°C ≥ indoor temperature ≥ set value + 2°C). The parameter conditions for low load are that the indoor temperature is close to the set value (set value + 2°C > indoor temperature).

[0092] This intelligent matching design of the load demand level realizes the energy - efficient operation of the heat pump system within the full operating range and avoids resource waste by pre - establishing an accurate mapping relationship among the working mode, load demand level, and operating parameters, and collecting actual operating parameters in real - time during the operation of the heat pump system to accurately identify the load status.

[0093] As Figure 8 shown, corresponding control logics are formulated based on different load demands. Specifically, the load demand level includes high load, medium load, and low load. The specific control logics of the compressor and heat exchanger combination are described in detail below.

[0094] If the heat pump system is at high load, reduce the liquid storage volume of the idle heat exchanger, increase the operating frequency of the compressor to the set high - frequency range (for example, increase to 70 Hz), increase the refrigerant circulation flow rate in the main circulation loop to the set high - volume range (for example, increase to 10 L / min), concentrate all the refrigerant into the main circulation loop, and the functional heat exchanger increases the energy output to quickly meet the user's usage requirements.

[0095] During the process of reducing the liquid storage volume of the idle heat exchanger, close the valve on the inlet side of the idle heat exchanger, gradually open the valve on the outlet side of the idle heat exchanger. The refrigerant stored in the idle heat exchanger is replenished into the main circulation loop until the refrigerant circulation flow rate in the main circulation loop increases to the set high - volume range, and then close the valve on the outlet side of the idle heat exchanger.

[0096] If the heat pump system is at medium load, adjust the liquid output of the idle heat exchanger, keep the operating frequency of the compressor in the set moderate range (for example, 55 Hz - 65 Hz), and keep the refrigerant circulation flow rate in the main circulation loop in the set medium - volume range (for example, 6 L / min - 8 L / min) to balance heat recovery and refrigerant storage.

[0097] During the process of adjusting the liquid output of the idle heat exchanger, when the refrigerant circulation flow rate in the main circulation loop is higher than the set medium flow rate range, close the valve on the outlet side of the idle heat exchanger, and gradually open the valve on the inlet side of the idle heat exchanger until the refrigerant circulation flow rate in the main circulation loop returns to the set medium flow rate range, then close the valve on the inlet side of the idle heat exchanger; when the refrigerant circulation flow rate in the main circulation loop is lower than the set medium flow rate range, close the valve on the inlet side of the idle heat exchanger, and gradually open the valve on the outlet side of the idle heat exchanger until the refrigerant circulation flow rate in the main circulation loop returns to the set medium flow rate range, then close the valve on the outlet side of the idle heat exchanger.

[0098] If the heat pump system is in a low load condition, increase the liquid storage capacity of the idle heat exchanger, reduce the operating frequency of the compressor to the set low frequency range (for example, reduce it to 40 Hz), reduce the refrigerant circulation flow rate in the main circulation loop to the set low flow rate range (for example, reduce it to 3 L / min), reduce the load of the functional heat exchanger, and avoid excessive refrigerant staying in the heat exchanger in the main circulation loop, which may lead to a decrease in heat exchange efficiency and an increase in flow resistance.

[0099] During the process of increasing the liquid storage capacity of the idle heat exchanger, close the valve on the outlet side of the idle heat exchanger, and gradually open the valve on the inlet side of the idle heat exchanger. The main circulation loop recovers the refrigerant stored in the idle heat exchanger until the refrigerant circulation flow rate in the main circulation loop decreases to the set high flow rate range, then close the valve on the inlet side of the idle heat exchanger.

[0100] This design combines the operating conditions of the heat pump system, the operating frequency of the compressor, and the refrigerant storage capacity of the idle heat exchanger. When the operating frequency of the compressor increases, the demand for refrigerant in the main circulation loop is large; when the operating frequency of the compressor decreases, the demand for refrigerant in the main circulation loop is small. The idle heat exchanger adjusts according to the refrigerant demand of the main circulation loop, enabling the operating state of the system to accurately match the current operating conditions and adapt to different working modes and user requirements.

[0101] It should be noted that the refrigerant circulation flow rate is generally detected at the suction side of the compressor. Since there is usually a gas-liquid separator at the suction side of the compressor, in order to improve the accuracy of the refrigerant circulation flow rate, it is preferred to detect the refrigerant flow rate in the inlet pipe of the gas-liquid separator as the refrigerant circulation flow rate in the main circulation loop.

[0102] In order to enable the operating performance of the heat pump system to quickly match the high load operating conditions, the present invention also designs an auxiliary heating control logic for the idle heat exchanger, which is specifically as follows:

[0103] When it is necessary to reduce the liquid storage capacity of the idle heat exchanger, detect the heat transfer medium temperature and the output refrigerant flow rate of the idle heat exchanger;

[0104] If the temperature of the heat exchange medium is lower than the set lower limit temperature (e.g., less than 25°C) and the output refrigerant flow rate is lower than the set lower limit flow rate (e.g., less than 5 L / min), it indicates that the refrigerant output speed of the current idle heat exchanger is relatively slow. Then, turn on the auxiliary heating device to provide heat to prompt the refrigerant to flow out of the idle heat exchanger more quickly.

[0105] And / or if the temperature of the heat exchange medium is higher than the set upper limit temperature (e.g., above 35°C) and the output refrigerant flow rate is higher than the set upper limit flow rate (e.g., above 10 L / min), it indicates that the refrigerant output speed of the current idle heat exchanger is relatively fast. Then, turn off the auxiliary heating device to prevent the refrigerant from causing a large impact on the main circulation loop and affecting the operational reliability of the system.

[0106] Among them, the temperature of the heat exchange medium is the temperature of the heat exchange medium that undergoes heat exchange with the refrigerant stored in the idle heat exchanger. If the heat exchange medium is water (such as an air conditioner water heat exchanger or a hot water heat exchanger), the temperature of the heat exchange medium is the water temperature of the idle heat exchanger; if the heat exchange medium is air (such as a fin heat exchanger), the temperature of the heat exchange medium is the ambient temperature where the idle heat exchanger is located.

[0107] This design can provide heat by turning on the auxiliary heating device when the temperature of the idle heat exchanger is too low, prompting the refrigerant to flow out of the idle heat exchanger, so that the amount of refrigerant in the main circulation loop can quickly match the current working conditions, greatly improving the heat exchange performance of the heat pump system and optimizing the user experience.

[0108] It should be noted that in some feasible embodiments of the present invention, the heat pump system can operate in a composite working mode with two supply functions, and the composite working mode is configured with the priority of the supply functions.

[0109] The control method further includes:

[0110] After obtaining the working mode and actual operating parameters of the heat pump system, determine whether the working mode is a composite working mode;

[0111] If so, select the supply function with a higher priority and its actual operating parameters to analyze the load demand level, and adjust the working states of the compressor and the heat exchanger combination according to the load demand level.

[0112] Among them, the priority of the supply function is set by the user and / or default setting.

[0113] It should be noted that in some embodiments, the composite working modes of the heat pump system include the cooling plus domestic hot water supply mode and the heating plus domestic hot water supply mode. Since the refrigerant flow directions for the two supply functions in the heating plus domestic hot water supply mode are different, these two supply functions can be adjusted relatively independently and switch between each other during operation. Specifically, the supply function with a higher priority and its actual operating parameters are selected to analyze the load demand level, and the operating states of the compressor and heat exchanger combination are adjusted according to the load demand level until the preset shutdown condition of the supply function with a higher priority is reached. Then, the supply function with a lower priority and its actual operating parameters are selected to analyze the load demand level, and the operating states of the compressor and heat exchanger combination are adjusted according to the load demand level until the preset shutdown condition of the supply function with a lower priority is reached.

[0114] Through intelligent load demand level analysis and function priority management, the optimized operation of the system under dual heating conditions is achieved. Its core advantage lies in that when the system is in the composite heating mode, based on the priority settings preset or default by the user (such as giving priority to ensuring domestic hot water supply or giving priority to meeting heating demand), key operating parameters (water temperature, flow rate, etc.) are automatically selected to determine the load level, thereby dynamically adjusting the compressor frequency and refrigerant circulation flow rate to improve the energy efficiency and stability of the system.

[0115] In practical applications, safety protection measures can also be added to the control scheme. For example, overheat protection. When the refrigerant temperature exceeds the safety upper limit (such as 120°C), the compressor frequency is immediately reduced to reduce the refrigerant circulation flow rate. When the refrigerant temperature is lower than the safety lower limit (such as -30°C), the compressor frequency is increased to increase the refrigerant circulation flow rate.

[0116] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. For the execution order of actions, steps, etc. in the devices and methods shown in the specification and drawings, as long as there is no specific explicit order limitation and the output of the previous process is not used in the subsequent process, they can be implemented in any order. The similar sequential terms used for convenience of description do not mean that they must be implemented in such an order.

[0117] Techniques, methods, and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods, and equipment should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary, not as limitations. Thus, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof in subsequent drawings is not required.

[0118] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A heat recovery heat pump system, comprising: Compressor and heat exchanger combination, characterized in that the heat exchanger combination includes: three heat exchangers; The second end of the first heat exchanger is connected to the second end of the second heat exchanger through a first valve, the first end of the first heat exchanger is connected to the second end of the third heat exchanger through a second valve, the first end of the second heat exchanger is connected to the second end of the third heat exchanger through a third valve, and the second end of the first heat exchanger is connected to the first end of the third heat exchanger through a fourth valve; The second end of the first heat exchanger is connected to the second end of the third heat exchanger through a first throttling branch, the second end of the second heat exchanger is connected to the second end of the first heat exchanger through a second throttling branch, and the second end of the second heat exchanger is connected to the second end of the third heat exchanger through a third throttling branch; Wherein, the exhaust side of the compressor can be switched to connect to the first end of any one of the heat exchangers. When two heat exchangers are connected to the compressor to form a main circulation loop, the remaining one heat exchanger can be used as a standby heat exchanger for storing refrigerant.

2. The heat recovery type heat pump system according to claim 1, characterized in that, The first heat exchanger is an air-conditioning water heat exchanger, the second heat exchanger is a hot water heat exchanger, the third heat exchanger is an external heat exchanger, and the working modes of the heat pump system include at least one of a cooling mode, a heating mode, a hot water supply mode, a cooling plus hot water supply mode, and a heating plus hot water supply mode.

3. The heat recovery heat pump system according to claim 2, characterized in that When the heat pump system operates in the cooling mode, the first heat exchanger serves as an evaporator, the third heat exchanger serves as a condenser, the second heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the first valve and the third valve; And / or when the heat pump system operates in the heating mode, the first heat exchanger serves as a condenser, the third heat exchanger serves as an evaporator, the second heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the first valve and the third valve; And / or when the heat pump system operates in the hot water supply mode, the second heat exchanger serves as a condenser, the third heat exchanger serves as an evaporator, the first heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the first valve and the second valve; And / or when the heat pump system operates in the cooling plus hot water supply mode, the first heat exchanger serves as an evaporator, the second heat exchanger serves as a condenser, the third heat exchanger serves as a standby heat exchanger, and the refrigerant storage state is adjusted through the third throttling branch and the fourth valve; And / or when the heat pump system operates in the heating plus hot water supply mode, the first heat exchanger or both of the second heat exchangers serve as condensers, the third heat exchanger serves as an evaporator, and the remaining one heat exchanger serves as a standby heat exchanger.

4. The heat recovery heat pump system according to claim 1, characterized in that, The first throttling branch is provided with a first throttling valve and a second throttling valve, and the second throttling valve is connected between the first throttling valve and the second end of the first heat exchanger; the second end of the second heat exchanger is connected between the first throttling valve and the second throttling valve through a control valve; Wherein, the control valve and the second throttling valve constitute the second throttling branch, and the control valve and the first throttling valve constitute the third throttling branch.

5. The heat recovery type heat pump system according to claim 1, characterized in that, The compressor is connected to the heat exchanger combination through two four-way valves; The D end of the first four-way valve is connected to the exhaust side of the compressor, the E end is connected to the first end of the first heat exchanger, the S end is connected to the suction side of the compressor, and the C end is connected to the D end of the second four-way valve; The C end of the second four-way valve is connected to the first end of the third heat exchanger, the E end is connected to the first end of the second heat exchanger, and the S end is connected to the suction side of the compressor.

6. The heat recovery type heat pump system according to any one of claims 1 to 5, characterized in that, The idle heat exchanger is configured with an auxiliary heating device for raising the temperature of the refrigerant. When the auxiliary heating device is controlled to be turned on, it provides heat to prompt the refrigerant to flow out of the idle heat exchanger.

7. Control method of a heat recovery heat pump system, the control method being applied to the heat recovery heat pump system according to any one of claims 1 to 6, characterized in that, Including: Obtain the working mode and actual operating parameters of the heat pump system; Analyze the load demand level according to the working mode and the actual operating parameters; Adjust the working state of the compressor and the heat exchanger combination according to the load demand level.

8. The control method according to claim 7, characterized in that, Analyzing the load demand level according to the working mode and the actual operating parameters includes: Pre-establish a correspondence relationship among the working mode, the load demand level, and the parameter conditions; Obtain the corresponding load demand level from the correspondence relationship according to the working mode and the actual operating parameters.

9. The control method according to claim 8, wherein The load demand level includes high load, medium load, and low load. Adjusting the working state of the compressor and the heat exchanger combination according to the load demand level includes: If the heat pump system is in a high load state, reduce the liquid storage volume of the idle heat exchanger, increase the operating frequency of the compressor to the set high-frequency range, and increase the refrigerant circulation flow rate in the main circulation loop to the set high-flow range; If the heat pump system is in a medium load state, adjust the liquid output volume of the idle heat exchanger, keep the operating frequency of the compressor in the set moderate range, and keep the refrigerant circulation flow rate in the main circulation loop in the set medium-flow range; If the heat pump system is in a low load state, increase the liquid storage volume of the idle heat exchanger, reduce the operating frequency of the compressor to the set low-frequency range, and reduce the refrigerant circulation flow rate in the main circulation loop to the set low-flow range.

10. The control method according to claim 9, characterized in that Adjusting the working state of the compressor and the heat exchanger combination according to the load demand level further includes: When reducing the liquid storage volume of the idle heat exchanger, detect the heat exchange medium temperature and the output refrigerant flow rate of the idle heat exchanger; If the heat exchange medium temperature is lower than the set lower limit temperature and the output refrigerant flow rate is lower than the set lower limit flow rate, turn on the auxiliary heating device to provide heat to prompt the refrigerant to flow out of the idle heat exchanger; And / or if the heat exchange medium temperature is higher than the set upper limit temperature and the output refrigerant flow rate is higher than the set upper limit flow rate, turn off the auxiliary heating device; Wherein, the heat exchange medium temperature is the temperature of the heat exchange medium that exchanges heat with the refrigerant stored in the idle heat exchanger.

11. The control method according to claim 7, wherein The heat pump system can operate in a composite working mode with two supply functions, and the composite working mode is configured with the priorities of the two supply functions; The control method further includes: After obtaining the working mode and actual operating parameters of the heat pump system, determine whether the working mode is a composite working mode; If so, select the supply function with a high priority and analyze the load demand level based on its actual operating parameters, and adjust the operating states of the compressor and the heat exchanger combination according to the load demand level; Among them, the priority of the supply function is set by the user and / or set by default.

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