Cold and heat combined dual-source heat pump unit using waste heat of return water of central heating user side

Abstract

The application provides a cold-heat combined supply dual-source heat pump unit using central heating user side return water waste heat, in a combined heating mode, a water supply pipeline supplies heat to a radiator, return water returns to a return water pipeline after passing through a heat exchanger; the return water pipeline and the upper input end and the lower output end of the heat exchanger are communicated, the upper output end is communicated with the inlet end of a compressor, the outlet end of the compressor is communicated with the inlet end of a heat pump indoor unit through an oil separator, the heat pump indoor unit is communicated with an electronic expansion valve through a liquid storage tank, the outlet end of the electronic expansion valve is communicated with the lower input end of the heat exchanger, the heat exchanger absorbs return water heat, and heating is supplemented through the heat pump indoor unit; in a refrigeration mode, the refrigerant outlet end of the air-cooled heat exchanger is communicated with the inlet end of the liquid storage tank, the outlet end of the liquid storage tank is communicated with the electronic expansion valve, the outlet end of the electronic expansion valve is communicated with the heat pump indoor unit, the outlet end of the heat pump indoor unit is communicated with the compressor, the outlet end of the compressor is communicated with the oil separator, and the outlet end of the oil separator is communicated with the air-cooled heat exchanger.

Description

Technical Field

[0001] This invention relates to the field of heating, ventilation, air conditioning and heat pump technology, and in particular to a dual-source heat pump unit that utilizes the waste heat of the return water on the user side of a centralized heating system. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Currently, centralized heating is the primary mode of winter heating in northern my country. Its heat sources include coal, gas, combined heat and power (CHP), and industrial waste heat, supplying heat to residential and commercial buildings through hot water or steam pipe networks. This mode offers advantages such as high heating stability, wide coverage, and low operating costs for users. However, it also has shortcomings: the large heating radius of the large pipe network leads to long time lags, and welfare-oriented heating policies result in generally high return water temperatures, leading to high energy consumption in some areas and insufficient system operation and regulation capabilities, making it difficult to meet the differentiated and refined heating needs of users. Against this backdrop, decentralized peak-shaving systems serve as an effective supplement to centralized heating. These systems introduce locally sourced heat sources with autonomous regulation capabilities at different levels of the heating network, effectively shortening thermal response time, mitigating main system load fluctuations, and improving the overall efficiency and dynamic adaptability of the heating system.

[0004] Existing residential dual-source heat pump systems achieve user-side flexibility and personalized peak shaving in centralized heating systems by configuring high-efficiency heat pumps, such as air-source or water-source heat pumps, on the user side. However, existing residential dual-source heat pump systems have the following problems: water-source heat pumps require a stable water supply and have high installation costs, while air-source heat pumps are easily affected by low outdoor temperatures during heating operations, resulting in reduced usable heat and an increased risk of evaporator frosting, leading to frequent defrosting, significantly reduced operating efficiency, and low control flexibility. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a dual-source heat pump unit that utilizes the waste heat of the return water on the user side of centralized heating, which can solve or at least alleviate the above problems. By recovering and utilizing the waste heat in the return water of centralized heating, it can effectively meet the user's personalized adjustment needs for the indoor environment while taking into account the energy efficiency of both heating and cooling modes, and achieve a synergistic improvement in the operating efficiency and control flexibility of the household heat pump system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A dual-source heat pump unit utilizing waste heat from the return water of a centralized heating user-side system includes a centralized heating unit and a user unit. The centralized heating unit includes a centralized heating user-side water supply pipe and a centralized heating user-side water return pipe. Hot water is transported to the user unit via the centralized heating user-side water supply pipe, and after heat exchange, it returns to the user unit via the centralized heating user-side water return pipe. The dual-source heat pump unit can achieve both heating and cooling modes, with the heating mode including a combined centralized heating and heat pump heating mode. The user unit includes a spiral coil heat exchanger, a variable frequency compressor, an oil separator, a heat pump indoor unit, a liquid storage tank, an electronic expansion valve, and an air-cooled heat exchanger. In the combined centralized heating and heat pump heating mode, the centralized heating user-side water supply pipe supplies heat to the radiators of the user unit, and the returned water flows through the spiral coil heat exchanger and returns to the centralized heating unit. The return water pipe on the user side of the central heating system is connected to the upper input and lower output ends of the spiral coil heat exchanger. The upper output end of the spiral coil heat exchanger is connected to the inlet end of the variable frequency compressor. The outlet end of the variable frequency compressor is connected to the inlet end of the heat pump indoor unit via an oil separator. The heat pump indoor unit is connected to the electronic expansion valve via a liquid storage tank. The outlet end of the electronic expansion valve is connected to the lower input end of the spiral coil heat exchanger. The spiral coil heat exchanger absorbs heat from the return water and supplements heating through the heat pump indoor unit. In cooling mode, the refrigerant outlet end of the air-cooled heat exchanger is connected to the inlet end of the liquid storage tank. The outlet end of the liquid storage tank is connected to the electronic expansion valve. The outlet end of the electronic expansion valve is connected to the heat pump indoor unit. The outlet end of the heat pump indoor unit is connected to the variable frequency compressor. The outlet end of the variable frequency compressor is connected to the oil separator. The outlet end of the oil separator is connected to the air-cooled heat exchanger.

[0007] Preferably, the heating mode also includes a basic heating mode, in which hot water flows from the centralized heating user-side water supply pipe into the radiator of the user unit, and the returned water after heat dissipation returns through the centralized heating user-side return water pipe.

[0008] Preferably, the heating mode also includes a heat pump-only heating mode. In the heat pump-only heating mode, the return water pipe on the user side of the centralized heating system is connected to the upper input end and the lower output end of the spiral coil heat exchanger. The upper output end of the spiral coil heat exchanger is connected to the inlet end of the variable frequency compressor. The outlet end of the variable frequency compressor is connected to the inlet end of the heat pump indoor unit via an oil separator. The heat pump indoor unit is connected to the electronic expansion valve via a liquid storage tank. The outlet end of the electronic expansion valve is connected to the lower input end of the spiral coil heat exchanger.

[0009] Preferably, the user unit further includes a controller, a data acquisition module, and an actuator drive module; the controller is connected to the data acquisition module and the actuator drive module respectively, the data acquisition module is used to collect real-time operating parameters of the combined cooling and heating dual-source heat pump unit, and the actuator drive module is used to receive control commands generated by the controller and drive the corresponding actuators to operate.

[0010] Preferably, in the heating mode, the user unit is configured to perform the following steps: S11. Obtain the user-set heating temperature. and real-time indoor temperature It also obtains the intake temperature, intake pressure, exhaust temperature, exhaust pressure, return water inlet temperature, return water outlet temperature, return water flow rate, and evaporation temperature. S12. Determine whether the collected data is within the preset valid range; S13. Determine the basic heating mode, heat pump heating only mode, or a combination of centralized heating and heat pump heating mode based on the user's selection. S14. Determine the target operating frequency of the inverter compressor based on the real-time indoor temperature. The room temperature control deviation in heating mode is: ; In the formula, The heating room temperature control deviation at the kth sampling time; The heating temperature set by the user; The real-time indoor temperature measured by the indoor temperature sensor at the k-th sampling time; S15. Adjust the opening of the electronic expansion valve according to the actual superheat. The superheat control deviation is:

[0011] In the formula, The superheat control deviation at the k-th sampling time; The actual refrigerant superheat at the k-th sampling time; Preset superheat; S16. Adjust the opening of the proportional regulating valve on the return water side or the return water flow rate according to the evaporation temperature. The evaporation temperature control deviation is:

[0012] In the formula, The evaporation temperature control deviation at the kth sampling time; Set the evaporation temperature. This refers to the real-time evaporation temperature. S17. The controller adjusts the fan speed of the heat pump indoor unit according to the indoor temperature deviation; S18. Continuously evaluate the unit's operating status. When a heat metering module and an input power metering module are installed, the heat pump coefficient of performance is calculated according to the following formula:

[0013] In the formula, This refers to the heating capacity output by the indoor unit of the heat pump into the room. This refers to the total input power of the variable frequency compressor, fan, and return water conveying equipment. S19. Continuously monitor indoor temperature.

[0014] Preferably, in the cooling mode, the user unit is configured to perform the following steps: S21. Obtain the user-set cooling temperature. Real-time indoor temperature Intake temperature, intake pressure, exhaust pressure, exhaust temperature, heat pump indoor unit coil temperature, air-cooled heat exchanger condensing pressure or condensing temperature, and outdoor air temperature; S22. According to the valve status corresponding to the cooling mode, open the first solenoid valve and the second solenoid valve, close the third solenoid valve to the ninth solenoid valve, and control the operation of the inverter compressor, electronic expansion valve, heat pump indoor unit and air-cooled heat exchanger. S23. Adjust the operating frequency of the inverter compressor according to the indoor temperature deviation. The room temperature control deviation in cooling mode is: ; In the formula, The temperature control deviation of the cooling system at the kth sampling time; The cooling temperature set by the user; S24. Determine the refrigerant superheat at the outlet of the heat pump indoor unit according to the aforementioned superheat calculation method, and adjust the opening of the electronic expansion valve according to the superheat deviation. S25. Adjust the fan speed of the air-cooled heat exchanger according to the condensing pressure or condensing temperature. When the condensing pressure is used as the feedback quantity, the condensing pressure control deviation is:

[0015] In the formula, The exhaust pressure control deviation at the k-th sampling time; For real-time condensation pressure, Preset condensation pressure; S26. Implement anti-freeze control based on the coil temperature of the heat pump indoor unit; S27. Continuously monitor indoor temperature, superheat, condensing pressure, coil temperature and compressor operating status.

[0016] Preferably, the spiral coil heat exchanger includes a shell and a spiral tube disposed in the shell; the shell includes an outer shell and an inner shell sleeved inside the outer shell, forming a jacket between the outer shell and the inner shell, and the spiral tube is disposed in the jacket; the upper side of the outer shell is provided with an upper input end, and the lower side of the outer shell is provided with a lower output end. Return water flows in from the upper input end, flows through the jacket and exchanges heat with the spiral tube, and then flows out through the lower output end to the return water pipe on the user side of the centralized heating system; the spiral tube includes a spiral tube body, a lower input end and an upper output end, the lower input end is disposed adjacent to the lower output end, the upper output end is disposed adjacent to the upper input end, and the spiral tube body is connected between the lower input end and the upper output end.

[0017] Preferably, the lower input end and the upper output end are T-shaped tubes, and the spiral tube body is a double spiral tube, including a first spiral tube and a second spiral tube. The refrigerant enters from the lower input end, is divided into two parts, enters the first spiral tube and the second spiral tube respectively to exchange heat with the return water and gradually vaporizes, and then converges and is output at the upper output end.

[0018] Preferably, the first spiral tube and the second spiral tube are respectively provided with spiral guide ribs.

[0019] Preferably, in the combined heating mode of centralized heating and heat pump, the controller of the user unit operates according to a preset sampling period. For a proportional-integral-derivative (PID) control loop, the incremental PID calculation relationship is as follows: (Periodic control calculation is performed.)

[0020]

[0021]

[0022] In the formula, x Indicates the corresponding control loop; For the first Control deviation at each sampling time; For controller output; and These are proportional gain, integral gain, and derivative gain, respectively. and These represent the lower and upper limits of the output allowed by the corresponding actuator, respectively. This indicates a limit operation.

[0023] Compared with existing technologies, this invention recovers and utilizes the waste heat in the return water of centralized heating systems, and can effectively meet users' personalized adjustment needs for the indoor environment while taking into account the energy efficiency of both heating and cooling modes. It achieves a synergistic improvement in the operating efficiency and control flexibility of household heat pump systems, and is suitable for household heating and cooling needs. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 A schematic diagram of a dual-source heat pump unit utilizing waste heat from the return water on the user side of a centralized heating system, according to an embodiment of the present invention, is shown.

[0026] Figure 2A A schematic diagram of a 3kW spiral coil heat exchanger in heating mode is shown.

[0027] Figure 2B A plan view of a spiral coil heat exchanger from another direction is shown.

[0028] Figure 2C A plan view of a spiral coil heat exchanger from another direction is shown.

[0029] Figure 3 A schematic diagram of component connections in a basic heating mode is shown.

[0030] Figure 4 A schematic diagram of component connections is shown in the heat pump heating mode only.

[0031] Figure 5 A schematic diagram of component connections is shown in a combined heating mode of centralized heating and heat pump.

[0032] Figure 6 A schematic diagram of component connections in cooling mode is shown, with some components omitted.

[0033] Figure 7 The control flowchart of the combined cooling and heating heat pump unit in heating mode is shown.

[0034] Figure 8 The control flowchart of the combined cooling and heating heat pump unit in cooling mode is shown.

[0035] Figure 9 A schematic diagram of the control system is shown.

[0036] Figure labeling: 1-Heat pump indoor unit; 2-Central heating terminal radiator; 3-Underfloor heating coil; 4-Oil separator; 5-Variable frequency compressor; 6-Liquid receiver; 7-First solenoid valve; 8-Second solenoid valve; 9-Electronic expansion valve; 10-Air-cooled heat exchanger; 11-Third solenoid valve; 12-Fourth solenoid valve; 13-Spiral coil heat exchanger; 131-Shell; 311-Outer shell; 312-Inner shell; 313-Upper input terminal; 3 14-Lower output end; 132-Spiral tube; 320-Spiral tube body; 201-First spiral tube; 202-Second spiral tube; 203-Spiral guide rib; 321-Lower input end; 322-Upper output end; 14-Fifth solenoid valve; 15-Sixth solenoid valve; 16-Seventh solenoid valve; 17-Eighth solenoid valve; 18-Ninth solenoid valve; 19-Central heating user-side water supply pipe; 20-Central heating user-side return water pipe. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that 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.

[0040] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.

[0041] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0042] like Figure 1 As shown, the combined heating and cooling dual-source heat pump unit (hereinafter referred to as the combined heating and cooling dual-source heat pump unit) utilizing the waste heat of the return water from the user side of centralized heating provided by an embodiment of the present invention can realize heating mode and cooling mode according to demand. Heating modes include basic heating mode, heat pump-only heating mode, and a combined heating mode of centralized heating and heat pump. The combined heating and cooling dual-source heat pump unit includes a centralized heating unit and a user unit. The centralized heating unit includes a centralized heating user-side water supply pipe 19 and a centralized heating user-side water return pipe 20. Hot water is transported to the user unit via the centralized heating user-side water supply pipe 19, and after heat exchange, it is returned via the centralized heating user-side water return pipe 20. (See also...) Figure 3 The diagram illustrates a basic heating mode. In this mode, the radiators in the user unit (e.g., central heating terminal radiators 2 or underfloor heating coils 3) are connected via pipes between the central heating user-side supply pipe 19 and the central heating user-side return pipe 20. Hot water flows from the central heating user-side supply pipe 19 into the central heating terminal radiator 2 or underfloor heating coil 3, dissipates heat into the room through the central heating terminal radiator 2 or underfloor heating coil 3, and the returned water returns through the central heating user-side return pipe 20, fulfilling basic heating needs. In another basic heating mode, heating is provided solely through the central heating secondary network. The user-side supply water connects to the indoor central heating terminal radiator 2 or underfloor heating coil 3 for radiant heating, releasing heat into the room. After the hot water temperature decreases, it flows into the secondary network user-side return pipe. This scenario is suitable for spaces with fewer people or lower thermal comfort requirements, satisfying basic indoor temperatures.

[0043] In some embodiments, such as Figure 4As shown, the user unit includes a spiral coil heat exchanger 13, a variable frequency compressor 5, an oil separator 4, a heat pump indoor unit 1, a liquid storage tank 6, and an electronic expansion valve 9. Through the spiral coil heat exchanger 13, variable frequency compressor 5, oil separator 4, heat pump indoor unit 1, liquid storage tank 6, and electronic expansion valve 9, a heat pump-only heating mode is achieved in heating mode. The spiral coil heat exchanger 13 is connected to the return water pipe 20 on the user side of the centralized heating system via a pipeline. Simultaneously, the spiral coil heat exchanger 13 is also connected to the variable frequency compressor 5 and the electronic expansion valve 9 via pipelines. Pipelines connect the variable frequency compressor 5 to the oil separator 4, the oil separator 4 to the heat pump indoor unit 1, the heat pump indoor unit 1 to the liquid storage tank 6, and the liquid storage tank 6 to the electronic expansion valve 9. Specifically, in the heating mode, the heat pump heating mode is used only. The return water pipe 20 of the centralized heating user side is connected to the spiral coil heat exchanger 13 via the fifth solenoid valve 14. After the return water temperature decreases, it returns from the lower side of the spiral coil heat exchanger 13 shell to the return water pipe 20 of the centralized heating user side via the sixth solenoid valve 15, realizing the reuse of waste heat in the return water. The upper side of the spiral coil heat exchanger 13 tube is connected to the inlet end of the variable frequency compressor 5 via the third solenoid valve 11. The outlet end of the variable frequency compressor 5 is connected to the inlet end of the heat pump indoor unit 1 via the oil separator 4. The heat pump indoor unit 1 is connected to the electronic expansion valve 9 via the liquid storage tank 6. The outlet end of the electronic expansion valve 9 is connected to the spiral coil heat exchanger 13 via the fourth solenoid valve 12, thus completing the heat pump heating mode with only return water source. In the heat pump heating mode only, the waste heat of the return water on the user side of the secondary network of centralized heating is used as a low-temperature water source to form a high-temperature refrigerant through the heat pump, and then heats the room through the heat pump indoor unit 1. This scenario is applicable to spaces where there are no centralized heating terminal equipment (centralized heating terminal radiator 2 or underfloor heating coil 3), where the indoor temperature requirements are not high, or where frequent temperature adjustments are required.

[0044] The spiral coil heat exchanger 13 serves as the evaporator in heat pump heating mode only. Low-temperature, low-pressure liquid refrigerant enters from the lower tube, while the return water pipe 20 for centralized heating users enters from the upper shell. Inside the heat exchanger, the refrigerant absorbs waste heat from the return water and gradually vaporizes. The low-temperature, low-pressure gaseous refrigerant is discharged from the upper side of the tube under gravity and sent to the variable frequency compressor 5. The low-temperature return water is discharged from the lower side of the shell into the return water pipe 20 for centralized heating users, thus reusing the waste heat of the return water and reducing heating energy consumption. In this embodiment, the spiral coil heat exchanger 13 has a compact structure, large heat exchange area, and strong anti-fouling ability. It increases secondary flow to enhance heat transfer and improves heat transfer efficiency. It is suitable for scenarios with high heating return water temperature, poor water quality, and large flow fluctuations.

[0045] Also refer to Figures 2A to 2CThe spiral coil heat exchanger 13 includes a shell 131 and a spiral tube 132 disposed within the shell. The shell 131 includes an outer shell 311 and an inner shell 312 fitted inside the outer shell 311, forming a jacket between the outer shell 311 and the inner shell 312, with the spiral tube 132 disposed within the jacket. An upper inlet end 313 is provided on the upper side of the outer shell 311, and a lower outlet end 314 is provided on the lower side of the outer shell 311. Return water flows in from the upper inlet end 313, flows through the jacket and exchanges heat with the spiral tube 132, and then flows out through the lower outlet end 314 to the return water pipe 20 on the user side of the centralized heating system. The spiral tube 132 includes a spiral tube body 320, a lower inlet end 321, and an upper outlet end 322. The lower inlet end 321 is disposed adjacent to the lower outlet end 314, and the upper outlet end 322 is disposed adjacent to the upper inlet end 313. The spiral tube body 320 connects the lower inlet end 321 and the upper outlet end 322. Preferably, the lower input end 321 and the upper output end 322 are both T-shaped tubes, and the spiral tube body 320 is a double spiral tube, including a first spiral tube 201 and a second spiral tube 202. The refrigerant enters from the lower input end 321, and is divided into two parts, which enter the first spiral tube 201 and the second spiral tube 202 respectively to exchange heat with the return water and gradually vaporize. The refrigerant then converges and exits at the upper output end 322. The spiral tube body 320 adopts a double spiral tube form with the first spiral tube 201 and the second spiral tube 202 connected in parallel. After the refrigerant is split, it flows in parallel, increasing the contact heat exchange area with the return water and making the refrigerant distribution more uniform. This facilitates the full absorption of heat and gradual vaporization, avoids local overheating or overcooling, and improves heat exchange stability. Preferably, the first spiral tube 201 and the second spiral tube 202 have the same structure. The lower input end 321, the upper output end 322, the first spiral tube 201, and the second spiral tube 202 are all copper tubes.

[0046] Furthermore, spiral guide ribs 203 are respectively wound around the first spiral tube 201 and the second spiral tube 202, so that while the return water flows axially along the shell 131 in the jacket, a circumferential rotating secondary flow is generated. The secondary flow disturbance can effectively eliminate any dead zones or temperature stratification phenomena that may exist in the jacket, ensuring uniform contact between the return water and all parts of the spiral tube, preventing local heat exchange degradation, and improving the overall thermal performance consistency of the heat exchanger. In addition, the continuous secondary flow flushing effect can reduce the probability of impurities in the fluid depositing on the wall surface, which is particularly beneficial for centralized heating return water containing a small amount of impurities, reducing fouling thermal resistance and extending the cleaning and maintenance cycle of the heat exchanger. Preferably, the spiral guide ribs 203 have a rib height of 4 mm, a rib width of 2 mm, and a rib spacing of 4 mm.

[0047] In some embodiments, the user unit further includes an air-cooled heat exchanger 10. Figure 6A simplified schematic diagram of the cooling mode is shown for ease of understanding. In cooling mode, the air-cooled heat exchanger 10 acts as a heat pump condenser. High-temperature, high-pressure gaseous refrigerant releases heat to the outdoor air and condenses into high-pressure liquid refrigerant within the air-cooled heat exchanger 10. The refrigerant outlet of the air-cooled heat exchanger 10 is connected to the inlet of the liquid storage tank 6 via a first solenoid valve 7. The outlet of the liquid storage tank 6 is connected to an electronic expansion valve 9. The outlet of the electronic expansion valve 9 is connected to the heat pump indoor unit 1. The outlet of the heat pump indoor unit 1 is connected to the inverter compressor 5. The outlet of the inverter compressor 5 is connected to the oil separator 4. The outlet of the oil separator 4 is connected to the air-cooled heat exchanger 10 via a second solenoid valve 8, thus completing the combined heat pump cooling mode.

[0048] In some embodiments, a seventh solenoid valve 16 or an eighth solenoid valve 17 is installed on the pipe between the central heating terminal radiator 2 or the underfloor heating coil 3 and the central heating user-side water supply pipe 19. The central heating user-side water supply pipe 19 is connected to the inlet end of the seventh solenoid valve 16 or the eighth solenoid valve 17, and the outlet end of the seventh solenoid valve 16 or the eighth solenoid valve 17 is connected to the inlet end of the central heating terminal radiator 2 or the underfloor heating coil 3. The outlet end of the central heating terminal radiator 2 or the underfloor heating coil 3 is connected to the central heating user-side return water pipe 20 via a ninth solenoid valve 18.

[0049] Users can choose from basic heating mode, heat pump heating only mode, or a combination of central heating and heat pump heating mode according to their needs. Figure 5 A schematic diagram of a combined heating mode of centralized heating and heat pump is shown. In the combined heating mode of centralized heating and heat pump, the water supply pipe 19 on the user side of centralized heating is connected to the inlet end of the seventh solenoid valve 16 or the eighth solenoid valve 17, the outlet end of the seventh solenoid valve 16 or the eighth solenoid valve 17 is connected to the inlet end of the centralized heating terminal radiator 2 or the underfloor heating coil 3, and the outlet end of the centralized heating terminal radiator 2 or the underfloor heating coil 3 is connected to the return water pipe 20 on the user side of centralized heating via the ninth solenoid valve 18. Peak load is met by the return water source heat pump. The return water pipe 20 on the user side of the centralized heating system is connected to the spiral coil heat exchanger 13 via the fifth solenoid valve 14. After the return water temperature decreases, it returns from the lower side of the spiral coil heat exchanger 13 shell to the return water pipe 20 on the user side of the centralized heating system via the sixth solenoid valve 15, realizing the reuse of waste heat from the return water. The upper side of the spiral coil heat exchanger 13 tube is connected to the inlet end of the variable frequency compressor 5 via the third solenoid valve 11. The outlet end of the variable frequency compressor 5 is connected to the inlet end of the heat pump indoor unit 1 via the oil separator 4. The heat pump indoor unit 1 is connected to the electronic expansion valve 9 via the liquid storage tank 6. The outlet end of the electronic expansion valve 9 is connected to the spiral coil heat exchanger 13 via the fourth solenoid valve 12, thus completing the combined heating mode of centralized heating and heat pump.

[0050] In the basic heating mode, the seventh solenoid valve 16, the eighth solenoid valve 17 and the ninth solenoid valve 18 are opened, the first solenoid valve 7 to the sixth solenoid valve 15 are closed, the variable frequency compressor 5, the electronic expansion valve 9 and the heat pump indoor unit 1 stop operating, and only the central heating terminal radiator 2 and / or the underfloor heating coil 3 supply heat to the room.

[0051] In the heat pump heating mode only, the third solenoid valve 11 to the sixth solenoid valve 15 are opened, the variable frequency compressor 5, the electronic expansion valve 9 and the heat pump indoor unit 1 are put into operation, and the first solenoid valve 7, the second solenoid valve 8 and the seventh solenoid valve 16 to the ninth solenoid valve 18 are closed, so that the central heating return water passes through the return water side heat exchange channel of the spiral coil heat exchanger 13 in sequence, and the spiral coil heat exchanger 13 absorbs the waste heat of the return water.

[0052] In the combined heating mode of centralized heating and heat pump, the third solenoid valve 11 to the ninth solenoid valve 18 are opened, the variable frequency compressor 5, the electronic expansion valve 9 and the heat pump indoor unit 1 are put into operation, the first solenoid valve 7 and the second solenoid valve 8 are closed, so that the centralized heating terminal bears the basic heating load and the return water source heat pump bears the supplementary heating load.

[0053] In cooling mode, the first solenoid valve 7 and the second solenoid valve 8 are open, and the fans of the inverter compressor 5, electronic expansion valve 9, heat pump indoor unit 1, and air-cooled heat exchanger 10 are activated. The third solenoid valve 11 to the ninth solenoid valve 18 are closed. After the refrigerant is condensed by the air-cooled heat exchanger 10, it flows sequentially through the first solenoid valve 7, the liquid receiver 6, the electronic expansion valve 9, and the heat pump indoor unit 1. In the heat pump indoor unit 1, it evaporates and absorbs indoor heat, and then returns to the air-cooled heat exchanger 10 through the inverter compressor 5, the oil separator 4, and the second solenoid valve 8, thus forming a refrigeration cycle.

[0054] In some embodiments, the aforementioned solenoid valves can be used in conjunction with proportional solenoid valves or electro-hydraulic proportional valves for continuous flow regulation to form an electromagnetic flow control assembly for controlling the on / off state and flow rate of the heating medium and refrigerant.

[0055] In some embodiments, the user unit further includes a controller, a data acquisition module, and an actuator driver module. See also... Figure 9 The controller is connected to the data acquisition module and the actuator drive module respectively. The data acquisition module is used to collect the real-time operating parameters of the combined cooling and heating dual-source heat pump unit, and the actuator drive module is used to receive the control commands generated by the controller and drive the corresponding actuators to perform actions.

[0056] The data acquisition module is connected to the indoor temperature sensor, the heating evaporator outlet temperature sensor, the cooling evaporator outlet temperature sensor, the suction pressure sensor, the exhaust temperature sensor, the exhaust pressure sensor, the return water inlet temperature sensor, the return water outlet temperature sensor, the return water flow sensor, and the indoor unit coil temperature sensor.

[0057] An indoor temperature sensor is installed in the user's room to measure the real-time indoor temperature. A heating evaporator outlet temperature sensor is installed in the refrigerant outlet pipe of the spiral coil heat exchanger 13 to measure the temperature of the refrigerant leaving the spiral coil heat exchanger 13 in heating mode. A cooling evaporator outlet temperature sensor is installed in the refrigerant outlet pipe of the heat pump indoor unit 1 to measure the temperature of the refrigerant leaving the heat pump indoor unit 1 in cooling mode.

[0058] The suction pressure sensor is installed in the low-pressure suction line before the inlet of the variable frequency compressor 5 to measure the low-pressure side pressure of the refrigerant. The discharge temperature sensor and discharge pressure sensor are installed in the outlet line of the variable frequency compressor 5 to measure the compressor discharge temperature and discharge pressure, respectively.

[0059] A return water inlet temperature sensor is located at the upper input end 313 of the spiral coil heat exchanger 13, a return water outlet temperature sensor is located at the lower output end 314 of the spiral coil heat exchanger 13, and a return water flow sensor is located in the return water inlet pipe of the spiral coil heat exchanger 13. An indoor unit coil temperature sensor is located on the surface of the heat exchange coil of the heat pump indoor unit 1 and is used for anti-freezing control of the indoor unit coil in cooling mode.

[0060] The controller pre-stores the pressure and saturation temperature data of the refrigerant used, and calculates the real-time evaporation temperature based on the low-pressure side pressure measured by the suction pressure sensor.

[0061] In the formula, For the first Evaporation temperature at each sampling time; The low-pressure side pressure is measured by the inhalation pressure sensor; This indicates the relationship between the pressure of the refrigerant used and its saturation temperature.

[0062] In heating mode, the refrigerant superheat is calculated using the following formula:

[0063] In the formula, For the first The degree of heating superheat at each sampling time; The refrigerant outlet temperature of the spiral coil heat exchanger 13 is measured by the outlet temperature sensor of the heating evaporator. Let be the evaporation temperature at the k-th sampling time.

[0064] In cooling mode, the refrigerant superheat is calculated using the following formula:

[0065] In the formula, For the first Cooling superheat at each sampling time; The refrigerant outlet temperature of the indoor unit 1 of the heat pump is measured by the evaporator outlet temperature sensor. Let be the evaporation temperature at the k-th sampling time.

[0066] In heating mode, the controller determines the target operating frequency of the variable frequency compressor 5 based on the indoor temperature deviation, the target opening degree of the electronic expansion valve 9 based on the heating superheat deviation, and the target opening degree of the return water side proportional regulating valve based on the evaporation temperature deviation. When the opening degree of the return water side proportional regulating valve increases, the return water flow rate through the spiral coil heat exchanger 13 increases; when the opening degree of the return water side proportional regulating valve decreases, the return water flow rate through the spiral coil heat exchanger 13 decreases.

[0067] In cooling mode, the controller determines the target operating frequency of the inverter compressor 5 based on the indoor temperature deviation, the target opening degree of the electronic expansion valve 9 based on the cooling superheat deviation, the target fan speed of the air-cooled heat exchanger 10 based on the exhaust pressure deviation, and performs anti-freeze control based on the indoor unit coil temperature.

[0068] The actuator drive module is connected to the variable frequency compressor 5, the electronic expansion valve 9, the fan of the heat pump indoor unit 1, the fan of the air-cooled heat exchanger 10, the return water side proportional regulating valve, and the first solenoid valve 7 to the ninth solenoid valve 18, respectively. The actuator drive module is used to output the target operating frequency of the compressor, the target opening degree of the electronic expansion valve, the target speed of the heat pump indoor unit fan, the target speed of the air-cooled heat exchanger fan, the target opening degree of the return water side proportional regulating valve, and the opening and closing commands of each solenoid valve.

[0069] Before executing control operations, the controller verifies the validity of data from each sensor and the communication status of the equipment. When it detects that sensor data exceeds the preset valid range, data acquisition communication is interrupted, the suction pressure is lower than the preset low-pressure protection value, the exhaust pressure is higher than the preset high-pressure protection value, or the exhaust temperature is higher than the preset exhaust temperature protection value, the controller stops the variable frequency compressor 5, closes the electronic expansion valve 9 and the return water side proportional regulating valve, restores the first solenoid valve 7 to the ninth solenoid valve 18 to the shutdown state corresponding to the current operating mode, and records the fault type and the time of fault occurrence.

[0070] like Figure 7 As shown, the present invention also provides a control method for a combined cooling and heating dual-source heat pump unit, the control method including operation mode management, sensor data acquisition, PID control calculation, actuator command output, and operation safety protection. Figure 7 The control flow shown is mainly used for heat pump-only heating mode and combined heating mode of central heating and heat pump.

[0071] The controller operates according to a preset sampling period. The control operation is performed periodically. For any PID control loop, the incremental PID calculation relationship is as follows:

[0072]

[0073]

[0074] In the formula, x Indicates the corresponding control loop; For the first Control deviation at each sampling time; For controller output; and These are proportional gain, integral gain, and derivative gain, respectively. and These represent the lower and upper limits of the output allowed by the corresponding actuator, respectively. This indicates a limit operation.

[0075] When the controller output reaches its upper or lower limit, the controller pauses the integral accumulation of the deviation in the same direction, or corrects the integral term in the opposite direction based on the actual output value to suppress integral saturation. The controller can also limit the output variation between adjacent sampling periods to avoid sudden changes in compressor frequency, electronic expansion valve opening, fan speed, or proportional control valve opening.

[0076] The control method in heating mode includes the following steps.

[0077] S11. Obtain the user-set heating temperature. and real-time indoor temperature It also obtains the intake temperature, intake pressure, exhaust temperature, exhaust pressure, return water inlet temperature, return water outlet temperature, return water flow rate, and evaporation temperature.

[0078] S12. Determine if the collected data is within the preset valid range. If there is a sensor fault, communication fault, high-pressure fault, low-pressure fault, excessively high exhaust temperature, or abnormal compressor current, stop the variable frequency compressor 5, adjust the electronic expansion valve 9 to the preset safe opening, close or limit the proportional regulating valve on the return water side, and put the unit into fault protection mode. If no fault is detected, continue with subsequent control steps.

[0079] S13. Determine the basic heating mode, heat pump-only heating mode, or combined central heating and heat pump heating mode based on the user's selection. When the basic heating mode is selected, the controller controls the central heating terminal according to the opening and closing status of the solenoid valves corresponding to the basic heating mode and stops the heat pump circulation. When the heat pump-only heating mode or the combined central heating and heat pump heating mode is selected, the heat pump heating control is activated.

[0080] S14. Determine the target operating frequency of the inverter compressor 5 based on the real-time indoor temperature. The room temperature control deviation in heating mode is:

[0081] In the formula, The heating room temperature control deviation at the kth sampling time; The heating temperature set by the user; This represents the real-time indoor temperature measured by the indoor temperature sensor at the k-th sampling time.

[0082] When the indoor temperature is lower than the heating set temperature, the room temperature control deviation increases, and the controller increases the target operating frequency of the inverter compressor 5; when the indoor temperature gradually approaches the heating set temperature, the controller decreases the target operating frequency of the inverter compressor 5.

[0083] The controller allows setting the heating start-up temperature difference and the heating stop temperature difference. When the indoor temperature is lower than the difference between the heating set temperature and the heating start-up temperature difference, the inverter compressor 5 is allowed to start; when the indoor temperature is higher than the sum of the heating set temperature and the heating stop temperature difference, the operating frequency of the inverter compressor 5 is reduced or the inverter compressor 5 is stopped. The controller can also set the minimum running time and minimum shutdown time of the compressor to avoid frequent start-stop of the inverter compressor 5.

[0084] S15. Adjust the opening of the electronic expansion valve 9 according to the actual superheat. The superheat control deviation is:

[0085] In the formula, The superheat control deviation at the k-th sampling time; The actual refrigerant superheat at the k-th sampling time; This is the preset superheat level.

[0086] When the actual superheat is higher than the preset superheat, the controller increases the opening of the electronic expansion valve 9 to increase the refrigerant mass flow rate into the spiral coil heat exchanger 13; when the actual superheat is lower than the preset superheat, the controller decreases the opening of the electronic expansion valve 9 to reduce the refrigerant supply and prevent incompletely vaporized liquid refrigerant from entering the variable frequency compressor 5.

[0087] In a preferred embodiment, the preset superheat is 5°C, and the allowable opening range of the electronic expansion valve 9 is 10%~90%. The preset superheat and the opening range of the electronic expansion valve can be adjusted according to the refrigerant type, the inverter compressor model, and the rated capacity of the unit.

[0088] S16. Adjust the opening of the proportional control valve on the return water side or the return water flow rate according to the evaporation temperature. The evaporation temperature control deviation is:

[0089] In the formula, The evaporation temperature control deviation at the kth sampling time; Set the evaporation temperature. This represents the real-time evaporation temperature.

[0090] The controller compares the real-time evaporation temperature with the preset minimum evaporation temperature. and maximum evaporation temperature Comparison. When When this occurs, increase the opening of the proportional control valve on the return water side or increase the return water flow rate to enhance heat exchange between the return water and the refrigerant; when At that time, the opening of the proportional regulating valve on the return water side is continuously adjusted according to the evaporation temperature control deviation, and room temperature-compressor frequency control and superheat-electronic expansion valve opening control are executed simultaneously; when When necessary, reduce the opening of the proportional regulating valve on the return water side or reduce the return water flow, and limit the compressor frequency according to the exhaust pressure and compressor load.

[0091] Preferably, the evaporation temperature control range in the heating mode is 10~15℃, and the evaporation temperature setpoint is within the control range.

[0092] S17. The controller adjusts the fan speed of the heat pump indoor unit 1 according to the indoor temperature deviation. When the deviation between the indoor temperature and the heating set temperature is large, the fan speed of the heat pump indoor unit 1 is increased; when the indoor temperature is close to the heating set temperature, the fan speed of the heat pump indoor unit 1 is decreased, so as to achieve coordinated regulation of rapid response on the indoor side and energy delivery on the refrigerant side.

[0093] S18. Continuously evaluate the unit's operating status. The operating status evaluation parameters include at least one of the following: evaporation temperature, superheat, compressor operating frequency, return water flow rate, discharge pressure, discharge temperature, and heat pump coefficient of performance.

[0094] When a heat pump metering module and an input power metering module are installed, the coefficient of performance (COP) of the heat pump is calculated according to the following formula:

[0095] In the formula, The coefficient of performance of the heat pump at the k-th sampling time; The heat output of indoor unit 1 from the heat pump into the room. This represents the total input power of the variable frequency compressor 5, fan, and return water delivery equipment. The heat pump performance coefficient is used for upper-level optimization of operating parameters and does not replace real-time closed-loop control of superheat, evaporation temperature, and indoor temperature.

[0096] S19. Continuously monitor indoor temperature. When the indoor temperature enters and stabilizes within the user-set heating comfort range, maintain the current operating parameters or reduce the unit output; when the indoor temperature does not reach the set range, re-execute room temperature control, superheat control, and evaporation temperature control.

[0097] In some embodiments, the controller is also used to perform cooling mode control. In cooling mode, the spiral coil heat exchanger 13 and the central heating return water side control circuit are shut down, the heat pump indoor unit 1 acts as an evaporator, and the air-cooled heat exchanger 10 acts as a condenser.

[0098] Also refer to Figure 8 The control method in cooling mode includes the following steps.

[0099] S21. Obtain the user-set cooling temperature. Real-time indoor temperature The parameters include: intake temperature, intake pressure, exhaust pressure, exhaust temperature, indoor unit coil temperature of the heat pump, condensing pressure or condensing temperature of the air-cooled heat exchanger, and outdoor air temperature.

[0100] S22. According to the valve status corresponding to the cooling mode, open the first solenoid valve 7 and the second solenoid valve 8, close the third solenoid valve 11 to the ninth solenoid valve 18, and put the inverter compressor 5, electronic expansion valve 9, heat pump indoor unit 1 and air-cooled heat exchanger 10 into operation.

[0101] S23. Adjust the operating frequency of the inverter compressor 5 according to the indoor temperature deviation. The room temperature control deviation in cooling mode is:

[0102] In the formula, The temperature control deviation of the cooling system at the kth sampling time; The cooling temperature set by the user.

[0103] When the indoor temperature is higher than the cooling set temperature, the controller increases the target operating frequency of the inverter compressor 5; when the indoor temperature gradually approaches or falls below the cooling set temperature, the controller decreases the target operating frequency of the inverter compressor 5 or stops the inverter compressor 5.

[0104] S24. Determine the refrigerant superheat at the outlet of the heat pump indoor unit 1 according to the aforementioned superheat calculation method, and adjust the opening of the electronic expansion valve 9 according to the superheat deviation. When the actual superheat is too high, increase the opening of the electronic expansion valve 9; when the actual superheat is too low, decrease the opening of the electronic expansion valve 9.

[0105] S25. Adjust the fan speed of the air-cooled heat exchanger 10 according to the condensing pressure or condensing temperature. When the condensing pressure is used as the feedback quantity, the condensing pressure control deviation is:

[0106] In the formula, The exhaust pressure control deviation at the k-th sampling time; For real-time condensation pressure, Preset condensation pressure.

[0107] When the condensing pressure is higher than the preset condensing pressure, the fan speed of the air-cooled heat exchanger 10 is increased; when the condensing pressure is lower than the preset condensing pressure, the fan speed of the air-cooled heat exchanger 10 is decreased. When the condensing pressure exceeds the preset safety limit, the controller prioritizes reducing the operating frequency of the variable frequency compressor 5; if the condensing pressure continues to exceed the safety limit after reducing the compressor operating frequency, the variable frequency compressor 5 is stopped and enters the high-pressure protection state.

[0108] S26. Implement anti-freeze control based on the coil temperature of the heat pump indoor unit 1. When the coil temperature of the heat pump indoor unit 1 is lower than the preset anti-freeze temperature, reduce the operating frequency of the inverter compressor 5, reduce the opening of the electronic expansion valve 9, adjust the fan speed of the heat pump indoor unit 1, or stop the inverter compressor 5 to avoid frost or freezing of the indoor evaporator coil.

[0109] S27. Continuously monitor indoor temperature, superheat, condensing pressure, coil temperature, and compressor operating status. When the indoor temperature enters and stabilizes within the user-set cooling comfort range, maintain the current operating parameters or reduce the unit output; when the indoor temperature does not reach the set range, re-execute room temperature control, superheat control, and condensing pressure control.

[0110] Through the above control methods, a three-level closed-loop control is formed in the heating mode, which controls the indoor temperature and compressor frequency, the refrigerant superheat and electronic expansion valve opening, and the evaporation temperature and return water side proportional regulating valve opening; in the cooling mode, a three-level closed-loop control is formed, which controls the indoor temperature and compressor frequency, the refrigerant superheat and electronic expansion valve opening, and the exhaust pressure and air-cooled heat exchanger fan speed.

[0111] Example like Figure 3 As shown, this design is suitable for spaces with few people, short stays, or low thermal comfort requirements, where only basic indoor temperature needs to be met. The supply water pipe 19 on the user side of the centralized heating system is connected to the inlet of the radiator 2 or underfloor heating coil 3 at the centralized heating terminal via the seventh solenoid valve 16 or the eighth solenoid valve 17. Hot water exchanges heat with the indoor air through radiation and convection. Low-temperature water flows from the outlet of the radiator 2 or underfloor heating coil 3 to the return water pipe 20 on the user side of the centralized heating system via the ninth solenoid valve 18, thus fulfilling basic heating requirements.

[0112] like Figure 4As shown, this system is applied to spaces without centralized heating terminal equipment (central heating terminal radiators 2 or underfloor heating coils 3, etc.), where indoor temperature requirements are not high or frequent temperature adjustments are needed. Return water end: The return water pipe 20 on the user side of the centralized heating system is connected to the spiral coil heat exchanger 13 via the fifth solenoid valve 14. After the return water temperature decreases, it returns to the return water pipe 20 on the user side of the centralized heating system via the sixth solenoid valve 15, realizing the reuse of waste heat from the return water. This increases the temperature difference between the supply and return water in the secondary network of centralized heating, reducing energy consumption. Refrigerant end: Low-temperature, low-pressure liquid refrigerant absorbs heat from the return water and vaporizes through the spiral coil heat exchanger 13. The low-temperature, low-pressure gaseous refrigerant is connected to the variable frequency compressor 5 via the third solenoid valve 11 and is heated by the variable frequency compressor. The compressor 5 compresses the refrigerant into a high-temperature, high-pressure gaseous state. The gaseous refrigerant is then connected to the inlet of the heat pump indoor unit 1 via the oil separator 4 through the outlet of the variable frequency compressor. It exchanges heat with the indoor air in the heat pump indoor unit 1 and is connected to the spiral coil heat exchanger 13 via the liquid storage tank 6, electronic expansion valve 9, and fourth solenoid valve 12. The compressor frequency and expansion valve opening are adjusted in real time based on the return water temperature and flow rate to ensure that the evaporation temperature is controlled at 10-15℃, reduce compressor power consumption, and achieve energy-saving operation, thereby completing the heat pump heating mode with only return water source.

[0113] like Figure 5 As shown, centralized heating serves as the basic heat source, meeting the basic load demand, while the heat pump acts as a peak-shaving heat source, flexibly supplementing load fluctuations. Flexible supplementation and intelligent control are achieved through the heat pump indoor unit 1 to meet higher thermal comfort requirements. Basic load: The centralized heating user-side water supply pipe 19 is connected to the inlet end of the centralized heating terminal radiator 2 or underfloor heating coil 3 via the seventh solenoid valve 16 or the eighth solenoid valve 17. Hot water exchanges heat with the indoor air through radiation and convection. Low-temperature water flows from the outlet end of the centralized heating terminal radiator 2 or underfloor heating coil 3 to the centralized heating user-side return water pipe 20 via the ninth solenoid valve 18, thus achieving basic load heating. Peak load: The return water end is connected from the centralized heating user-side return water pipe 20 to the spiral coil heat exchanger 13 via the fifth solenoid valve 14. After the return water temperature decreases, it returns to the centralized heating user-side return water pipe 20 via the sixth solenoid valve 15, realizing the reuse of waste heat from the return water. The temperature difference between the supply and return water in the secondary network of centralized heating is increased, reducing energy consumption. At the refrigerant end, the low-temperature, low-pressure liquid refrigerant absorbs heat from the return water and vaporizes through the spiral coil heat exchanger 13. The low-temperature, low-pressure gaseous refrigerant is connected to the variable frequency compressor 5 through the third solenoid valve 11 and compressed into a high-temperature, high-pressure gaseous refrigerant by the variable frequency compressor 5. It is then connected to the inlet end of the heat pump indoor unit 1 through the oil separator at the outlet end of the variable frequency compressor. It exchanges heat with the indoor air in the heat pump indoor unit 1 and is connected to the spiral coil heat exchanger 13 through the liquid storage tank 6, electronic expansion valve 9, and fourth solenoid valve 12. By monitoring the return water temperature, the compressor frequency and the opening of the expansion valve are adjusted to dynamically regulate the return water utilization flow rate, thereby meeting the load requirements of different users.

[0114] like Figure 6As shown, in cooling mode, the heat pump indoor unit 1 acts as the evaporator, and the air-cooled heat exchanger 10 acts as the condenser. High-temperature, high-pressure gaseous refrigerant releases heat to the outdoor air and condenses into high-pressure liquid refrigerant in the air-cooled heat exchanger 10, then flows sequentially through the first solenoid valve 7, the liquid receiver 6, and the electronic expansion valve 9. The low-temperature, low-pressure gas-liquid two-phase refrigerant, after being throttled by the electronic expansion valve 9, enters the heat pump indoor unit 1, where it evaporates and absorbs indoor heat, forming a low-temperature, low-pressure gaseous refrigerant, which then enters the inverter compressor 5. The high-temperature, high-pressure gaseous refrigerant, after being compressed by the inverter compressor 5, flows sequentially through the oil separator 4 and the second solenoid valve 8, and returns to the air-cooled heat exchanger 10, thus completing the cooling cycle of the dual-source heat pump unit.

[0115] The dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating provided by this invention combines an air-source heat pump with a water-source heat pump to improve the year-round operating efficiency of the heat pump and the stability of centralized heating. In heating mode, the dual-source heat pump unit uses a spiral coil heat exchanger 13 as an evaporator and centralized heating return water as a low-temperature heat source to recover waste heat from the user side of centralized heating, avoiding the impact of low outdoor temperatures and frost on the heating performance of the air-source heat pump in winter. The controller adjusts the operating frequency of the variable frequency compressor 5, the opening degree of the electronic expansion valve 9, and the opening degree of the return water side proportional regulating valve according to the indoor temperature, refrigerant superheat, and evaporation temperature, respectively, to maintain the evaporation temperature within the preset operating range in heating mode.

[0116] In cooling mode, the heat pump indoor unit 1 acts as an evaporator to absorb indoor heat, while the air-cooled heat exchanger 10 acts as a condenser to release heat to the outdoor air. The controller adjusts the operating frequency of the inverter compressor 5, the opening degree of the electronic expansion valve 9, and the fan speed of the air-cooled heat exchanger 10 according to the indoor temperature, refrigerant superheat, and condensing pressure or condensing temperature, thereby meeting the user's cooling needs and maintaining stable unit operation.

[0117] The dual-source heat pump unit for combined heating and cooling provided by this invention can switch between basic heating mode, heat pump-only heating mode, combined heating mode with central heating and heat pump mode, and cooling mode according to user needs. It is suitable for residential and commercial buildings with central heating in northern cities. This unit can utilize the waste heat of the existing central heating return water, improve the temperature difference between the supply and return water of the secondary heating network and the efficiency of waste heat utilization, and achieve on-demand adjustment of indoor temperature through the coordinated control of variable frequency compressor, electronic expansion valve, return water side proportional regulating valve and fan, taking into account operational comfort, energy efficiency and equipment operation safety.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water of a centralized heating user-side system, comprising a centralized heating unit and a user unit, wherein the centralized heating unit includes a centralized heating user-side water supply pipe and a centralized heating user-side water return pipe, hot water is transported to the user unit via the centralized heating user-side water supply pipe, and after heat exchange, returns to the user unit via the centralized heating user-side water return pipe, characterized in that: The combined heating and cooling dual-source heat pump unit can realize heating mode and cooling mode. The heating mode includes centralized heating and heat pump combined heating mode. The user unit includes a spiral coil heat exchanger, variable frequency compressor, oil separator, heat pump indoor unit, liquid storage tank, electronic expansion valve and air-cooled heat exchanger. In the combined heating mode of centralized heating and heat pump, the centralized heating user-side water supply pipe supplies heat to the radiators of the user unit. The returned water after heat dissipation flows through the spiral coil heat exchanger and returns to the centralized heating user-side return water pipe. The centralized heating user-side return water pipe is connected to the upper input end and the lower output end of the spiral coil heat exchanger. The upper output end of the spiral coil heat exchanger is connected to the inlet end of the variable frequency compressor. The outlet end of the variable frequency compressor is connected to the inlet end of the heat pump indoor unit through the oil separator. The heat pump indoor unit is connected to the electronic expansion valve through the liquid storage tank. The outlet end of the electronic expansion valve is connected to the lower input end of the spiral coil heat exchanger. The spiral coil heat exchanger absorbs heat from the return water and supplements the heating through the heat pump indoor unit. In cooling mode, the refrigerant outlet of the air-cooled heat exchanger is connected to the inlet of the liquid receiver, the outlet of the liquid receiver is connected to the electronic expansion valve, the outlet of the electronic expansion valve is connected to the heat pump indoor unit, the outlet of the heat pump indoor unit is connected to the inverter compressor, the outlet of the inverter compressor is connected to the oil separator, and the outlet of the oil separator is connected to the air-cooled heat exchanger.

2. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 1, characterized in that, The heating mode also includes a basic heating mode, in which hot water flows from the centralized heating user-side water supply pipe into the radiator of the user unit, and the returned water after heat dissipation returns through the centralized heating user-side return water pipe.

3. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 1, characterized in that, The heating mode also includes a heat pump-only heating mode. In the heat pump-only heating mode, the return water pipe on the user side of the centralized heating system is connected to the upper input end and the lower output end of the spiral coil heat exchanger. The upper output end of the spiral coil heat exchanger is connected to the inlet end of the variable frequency compressor. The outlet of the variable frequency compressor is connected to the inlet end of the heat pump indoor unit via an oil separator. The heat pump indoor unit is connected to the electronic expansion valve via a liquid storage tank. The outlet end of the electronic expansion valve is connected to the lower input end of the spiral coil heat exchanger.

4. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to any one of claims 1 to 3, characterized in that, The user unit also includes a controller, a data acquisition module, and an actuator drive module; the controller is connected to the data acquisition module and the actuator drive module respectively. The data acquisition module is used to collect real-time operating parameters of the combined cooling and heating dual-source heat pump unit, and the actuator drive module is used to receive control commands generated by the controller and drive the corresponding actuators to operate.

5. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 4, characterized in that, In the heating mode, the user unit is configured to perform the following steps: S11. Obtain the user-set heating temperature. and real-time indoor temperature It also obtains the intake temperature, intake pressure, exhaust temperature, exhaust pressure, return water inlet temperature, return water outlet temperature, return water flow rate, and evaporation temperature. S12. Determine whether the collected data is within the preset valid range; S13. Determine the basic heating mode, heat pump heating only mode, or a combination of centralized heating and heat pump heating mode based on the user's selection. S14. Determine the target operating frequency of the inverter compressor based on the real-time indoor temperature. The room temperature control deviation in heating mode is: ； In the formula, The heating room temperature control deviation at the kth sampling time; The heating temperature set by the user; The real-time indoor temperature measured by the indoor temperature sensor at the k-th sampling time; S15. Adjust the opening of the electronic expansion valve according to the actual superheat. The superheat control deviation is: In the formula, The superheat control deviation at the k-th sampling time; The actual refrigerant superheat at the k-th sampling time; Preset superheat; S16. Adjust the opening of the proportional regulating valve on the return water side or the return water flow rate according to the evaporation temperature. The evaporation temperature control deviation is: In the formula, The evaporation temperature control deviation at the kth sampling time; Set the evaporation temperature. This refers to the real-time evaporation temperature. S17. The controller adjusts the fan speed of the heat pump indoor unit according to the indoor temperature deviation; S18. Continuously evaluate the unit's operating status. When a heat metering module and an input power metering module are installed, the heat pump coefficient of performance is calculated according to the following formula: In the formula, The coefficient of performance of the heat pump at the k-th sampling time; This refers to the heating capacity output by the indoor unit of the heat pump into the room. This refers to the total input power of the variable frequency compressor, fan, and return water conveying equipment. S19. Continuously monitor indoor temperature.

6. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 4, characterized in that, In the cooling mode, the user unit is configured to perform the following steps: S21. Obtain the user-set cooling temperature. Real-time indoor temperature Intake temperature, intake pressure, exhaust pressure, exhaust temperature, heat pump indoor unit coil temperature, air-cooled heat exchanger condensing pressure or condensing temperature, and outdoor air temperature; S22. According to the valve status corresponding to the cooling mode, open the first solenoid valve and the second solenoid valve, close the third solenoid valve to the ninth solenoid valve, and control the operation of the inverter compressor, electronic expansion valve, heat pump indoor unit and air-cooled heat exchanger. S23. Adjust the operating frequency of the inverter compressor according to the indoor temperature deviation. The room temperature control deviation in cooling mode is: ； In the formula, The temperature control deviation of the cooling system at the kth sampling time; The cooling temperature set by the user; S24. Determine the refrigerant superheat at the outlet of the heat pump indoor unit according to the aforementioned superheat calculation method, and adjust the opening of the electronic expansion valve according to the superheat deviation. S25. Adjust the fan speed of the air-cooled heat exchanger according to the condensing pressure or condensing temperature. When the condensing pressure is used as the feedback quantity, the condensing pressure control deviation is: In the formula, The exhaust pressure control deviation at the k-th sampling time; For real-time condensation pressure, Preset condensation pressure; S26. Implement anti-freeze control based on the coil temperature of the heat pump indoor unit; S27. Continuously monitor indoor temperature, superheat, condensing pressure, coil temperature and compressor operating status.

7. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 3, characterized in that, The spiral coil heat exchanger includes a shell and a spiral tube disposed in the shell; the shell includes an outer shell and an inner shell fitted inside the outer shell, forming a jacket between the outer shell and the inner shell, and the spiral tube is disposed in the jacket; the upper side of the outer shell is provided with an upper input end, and the lower side of the outer shell is provided with a lower output end. Return water flows in from the upper input end, flows through the jacket and exchanges heat with the spiral tube, and then flows out through the lower output end to the return water pipe on the user side of the centralized heating system; the spiral tube includes a spiral tube body, a lower input end and an upper output end, the lower input end is disposed adjacent to the lower output end, the upper output end is disposed adjacent to the upper input end, and the spiral tube body is connected between the lower input end and the upper output end.

8. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 7, characterized in that, The lower input end and the upper output end are T-shaped tubes, and the spiral tube body is a double spiral tube, including a first spiral tube and a second spiral tube. The refrigerant enters from the lower input end, is divided into two parts, enters the first spiral tube and the second spiral tube respectively to exchange heat with the return water and gradually vaporizes, and then converges and is output at the upper output end.

9. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 8, characterized in that, The first and second spiral tubes are respectively provided with spiral guide ribs.

10. The combined cooling and heating dual-source heat pump unit utilizing waste heat from the return water on the user side of centralized heating according to claim 1, characterized in that, In the combined heating mode of centralized heating and heat pump, the controller of the user unit operates according to a preset sampling period. For a proportional-integral-derivative (PID) control loop, the incremental PID calculation relationship is as follows: (Periodic control calculation is performed.) In the formula, x Indicates the corresponding control loop; For the first Control deviation at each sampling time; For controller output; and These are proportional gain, integral gain, and derivative gain, respectively. and These represent the lower and upper limits of the output allowed by the corresponding actuator, respectively. This indicates a limit operation.

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