Two-stage heat pump hot water system, control method and device and storage medium

Abstract

The application discloses a two-stage ejector heat pump hot water system, a control method and device and a storage medium, wherein the heat pump hot water system comprises an ejector compressor, a water tank, a primary economizer and a secondary economizer. The ejector compressor comprises an exhaust port, a suction port and an ejector port. The water tank is provided with a heat exchange coil, and the exhaust port is connected to an inlet of the heat exchange coil. The primary economizer comprises a primary main path and a primary auxiliary path. An outlet of the heat exchange coil is connected to an inlet of the primary main path. An inlet of the primary auxiliary path is connected to an outlet of the primary main path through a first expansion valve. An outlet of the primary auxiliary path is connected to the ejector port. The secondary economizer comprises a secondary main path and a secondary auxiliary path. An inlet of the secondary main path is connected to an outlet of the primary main path. An outlet of the secondary main path is connected to the suction port through an outdoor heat exchanger. An inlet of the secondary auxiliary path is connected to an outlet of the secondary main path through a second expansion valve. An outlet of the secondary auxiliary path is connected to the suction port. The embodiment of the application can be applied to different application scenarios and has good heating effect and energy-saving effect.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment technology, and in particular to a two-stage enthalpy heat pump water heating system, control method, device and storage medium. Background Technology

[0002] Currently, heat pump water heating systems use high-temperature refrigerant to heat water to meet the demand for hot water. However, in low-temperature and ultra-low-temperature environments, due to the excessively low evaporation temperature, the evaporation efficiency is low and evaporation is incomplete, which leads to a decrease in the unit's heating capacity, thus affecting the hot water production effect or preventing it from reaching the required high water temperature.

[0003] In related technologies, methods such as supplementing with electric heating devices for auxiliary heating, increasing the compressor's operating frequency, enlarging the outdoor unit's heat exchanger, or using a large-displacement compressor are generally adopted to improve the hot water production capacity of heat pump water heating systems at ultra-low temperatures. Although these methods can improve the low-temperature heating capacity of heat pump water heating systems to some extent, their application scenarios are limited due to objective factors such as excessively large machine size and limited equipment performance, and their heating and energy-saving effects are relatively poor. Summary of the Invention

[0004] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a two-stage enthalpy heat pump water heating system, control method, device and storage medium that can be applied to different application scenarios and has good heating effect and energy saving effect.

[0005] In a first aspect, embodiments of the present invention provide a two-stage enthalpy heat pump water heating system, comprising:

[0006] An enthalpy-injected compressor includes an exhaust port, an intake port, and an enthalpy-injected port.

[0007] A water tank is equipped with a heat exchange coil, and the exhaust port is connected to the inlet of the heat exchange coil;

[0008] The primary economizer includes a primary main circuit and a primary auxiliary circuit. The outlet of the heat exchange coil is connected to the inlet of the primary main circuit. The inlet of the primary auxiliary circuit is connected to the outlet of the primary main circuit through a first expansion valve. The outlet of the primary auxiliary circuit is connected to the enthalpy injection port.

[0009] The secondary economizer includes a secondary main road and a secondary auxiliary road. The inlet of the secondary main road is connected to the outlet of the primary main road, and the outlet of the secondary main road is connected to the air intake through an outdoor heat exchanger. The inlet of the secondary auxiliary road is connected to the outlet of the secondary main road through a second expansion valve, and the outlet of the secondary auxiliary road is connected to the air intake.

[0010] The two-stage enthalpy heat pump water heating system provided by the first aspect of the present invention has at least the following beneficial effects: the enthalpy compressor discharges the compressed high-temperature and high-pressure gaseous refrigerant from the exhaust port and outputs it to the inlet of the water tank equipped with a heat exchange coil. After the gaseous refrigerant enters the water tank through the inlet of the heat exchange coil, it releases heat and raises the water temperature in the water tank. The refrigerant after releasing heat flows out from the outlet of the heat exchange coil and flows to the inlet of the primary main circuit of the primary economizer. After heat exchange in the primary economizer, the refrigerant is output from the outlet of the primary main circuit of the primary economizer. When the first expansion valve is not open, the refrigerant is output to the inlet of the secondary main circuit of the secondary economizer and enters the secondary economizer. When the first expansion valve is open, part of the refrigerant is output to the inlet of the secondary main circuit of the secondary economizer and enters the secondary economizer, while the other part of the refrigerant flows to the inlet of the primary auxiliary circuit of the primary economizer after passing through the first expansion valve and enters the primary economizer from the inlet of the primary auxiliary circuit. The refrigerant is then throttled and sucked by the primary economizer. The refrigerant undergoes a heat exchange process, increasing the enthalpy difference and thus the heating capacity. This first-stage enthalpy increase results in excellent heating and energy-saving performance. The refrigerant then flows from the outlet of the first-stage auxiliary circuit to the enthalpy injection port of the enthalpy-injection compressor, returning to the compressor via the injection port. After heat exchange in the second-stage economizer, the refrigerant exits from the outlet of the second-stage main circuit. With the second expansion valve closed, the refrigerant flows through the outdoor heat exchanger to the suction port and returns to the compressor. With the second expansion valve open... In this process, a portion of the refrigerant flows through the outdoor heat exchanger to the suction port, then returns to the enthalpy-injected compressor. The other portion flows through the second expansion valve to the inlet of the secondary auxiliary circuit of the secondary economizer. Entering the secondary economizer from the inlet, the refrigerant further increases the enthalpy difference through the throttling and heat absorption effect, thereby increasing the heating capacity and achieving secondary enthalpy enhancement. This enhances both heating and energy-saving effects. The refrigerant then flows out from the outlet of the secondary auxiliary circuit back to the suction port and returns to the enthalpy-injected compressor. This embodiment of the invention, by setting up a primary and secondary economizer in a two-stage enthalpy-injected heat pump water heating system, achieves primary and secondary enthalpy enhancement, improving the ultra-low temperature heating capacity of the heat pump water heating system and enabling it to achieve good heating and energy-saving effects. Furthermore, by controlling the on / off states of the first and second expansion valves, different heating demands can be met, making the heat pump water heating system suitable for various application scenarios. In other words, this embodiment of the invention can be applied to different application scenarios and has good heating and energy-saving effects.

[0011] In one embodiment of the present invention, a four-way valve is further included, which is connected to the exhaust port, the intake port, the inlet of the heat exchange coil and the outdoor heat exchanger respectively.

[0012] In a second aspect, embodiments of the present invention provide an operation control method applied to the heat pump water heating system described in the first aspect, the method comprising:

[0013] The superheat of the refrigerant in the water tank and the outdoor ambient temperature are obtained. The superheat of the refrigerant in the water tank is obtained by subtracting the refrigerant temperature at the outlet of the heat exchange coil from the inlet refrigerant temperature of the heat exchange coil.

[0014] The opening and closing states of the first expansion valve and the second expansion valve are controlled based on the superheat of the refrigerant in the water tank and the outdoor ambient temperature.

[0015] The operation control method provided by the second aspect of the present invention has at least the following beneficial effects: by controlling the switching state of the first expansion valve and the second expansion valve through the superheat of the refrigerant in the water tank and the outdoor ambient temperature, different heating demands can be met, making the heat pump water heating system applicable to different application scenarios and achieving good heating and energy-saving effects.

[0016] In one embodiment of the present invention, in response to the superheat of the refrigerant in the water tank being less than a second set value and the outdoor ambient temperature being greater than or equal to a third set value, the first expansion valve is controlled to close and the second expansion valve is controlled to open.

[0017] In one embodiment of the present invention, the first expansion valve and the second expansion valve are controlled to open in response to the superheat of the refrigerant in the water tank being less than a second set value and the outdoor ambient temperature being less than a third set value.

[0018] In one embodiment of the present invention, in response to the superheat of the refrigerant in the water tank being greater than or equal to a second set value and less than a first set value, and the outdoor ambient temperature being greater than or equal to a third set value, the first expansion valve and the second expansion valve are controlled to close; the first set value is greater than the second set value.

[0019] In one embodiment of the present invention, in response to the superheat of the refrigerant in the water tank being greater than or equal to a second set value and less than a first set value, and the outdoor ambient temperature being greater than or equal to a fourth set value and less than a third set value, the first expansion valve is controlled to open and the second expansion valve is controlled to close; the third set value is greater than the fourth set value.

[0020] In one embodiment of the present invention, in response to the superheat of the refrigerant in the water tank being greater than or equal to a second set value and less than a first set value, and the outdoor ambient temperature being less than a fourth set value, the first expansion valve and the second expansion valve are controlled to open.

[0021] In one embodiment of the present invention, the opening of the first expansion valve is adjusted according to the first-stage superheat so that the first-stage superheat falls within a first set range; the first-stage superheat is obtained by subtracting the inlet temperature from the outlet temperature of the first-stage auxiliary circuit.

[0022] In one embodiment of the present invention, the opening of the two expansion valves is adjusted according to the exhaust superheat so that the secondary superheat falls into a second set range; the exhaust superheat is obtained by subtracting the water temperature in the water tank from the refrigerant temperature at the exhaust port.

[0023] In one embodiment of the present invention, adjusting the opening of the first expansion valve according to the first-stage superheat includes: increasing the opening of the first expansion valve when the first-stage superheat is greater than the upper limit of the first set range; and decreasing the opening of the first expansion valve when the first-stage superheat is less than the lower limit of the first set range.

[0024] In one embodiment of the present invention, adjusting the opening of the two expansion valves according to the exhaust superheat includes: increasing the opening of the second expansion valve when the exhaust superheat is greater than the upper limit of the second set range; and decreasing the opening of the second expansion valve when the exhaust superheat is less than the lower limit of the second set range.

[0025] In one embodiment of the present invention, in response to the superheat of the refrigerant in the water tank being greater than or equal to a first set value, the first expansion valve and the second expansion valve are controlled to close.

[0026] Thirdly, embodiments of the present invention provide an operation control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the operation control method as described in any of the second aspects.

[0027] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the operation control method as described in the second aspect.

[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0029] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0031] Figure 1This is a schematic diagram of the structure of a two-stage spray enthalpy heat pump water heating system provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the specific structure of the two-stage spray enthalpy heat pump water heating system provided in the embodiment of the present invention;

[0033] Figure 3 This is a flowchart illustrating an embodiment of the operation control method provided by the present invention;

[0034] Figure 4 This is a detailed flowchart of step S320 provided in one embodiment of the present invention;

[0035] Figure 5 This is a detailed flowchart of step S320 provided in another embodiment of the present invention;

[0036] Figure 6 This is a detailed flowchart of step S320 provided in another embodiment of the present invention;

[0037] Figure 7 This is a detailed flowchart of step S320 provided in another embodiment of the present invention;

[0038] Figure 8 This is a detailed flowchart of step S320 provided in another embodiment of the present invention;

[0039] Figure 9 This is a schematic flowchart of adjusting the opening degree of the first expansion valve according to an embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of the process for adjusting the opening of the second expansion valve according to an embodiment of the present invention;

[0041] Figure 11 This is a schematic diagram of the structure of a control and operation device provided in one embodiment of the present invention. Detailed Implementation

[0042] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0043] In the description of this invention, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0044] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0045] This invention provides a two-stage enthalpy heat pump water heating system, an operation control method, an operation control device, and a computer-readable storage medium. By setting a primary economizer and a secondary economizer in the two-stage enthalpy heat pump water heating system, primary and secondary enthalpy increases are achieved, which improves the ultra-low temperature heating capacity of the heat pump water heating system, enabling it to achieve good heating and energy-saving effects. Furthermore, by controlling the on / off states of the first and second expansion valves, different heating demands can be met, making the heat pump water heating system suitable for various application scenarios. Therefore, this invention can be applied to different application scenarios and has good heating and energy-saving effects.

[0046] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0047] Reference Figure 1 A first aspect of the present invention provides a two-stage enthalpy heat pump water heating system 100, comprising: an enthalpy compressor 110, a water tank 120, an outdoor heat exchanger 150, a first-stage economizer 130, and a second-stage economizer 140.

[0048] The compressor 110 includes an exhaust port 111, an intake port 112, and an enthalpy injection port 113; a water tank 120 is equipped with a heat exchange coil 121, and the exhaust port 111 is connected to the inlet 122 of the heat exchange coil 121; a primary economizer 130 includes a primary main circuit and a primary auxiliary circuit, the outlet 123 of the heat exchange coil 121 is connected to the inlet of the primary main circuit, the inlet of the primary auxiliary circuit is connected to the outlet of the primary main circuit through a first expansion valve 131, and the outlet of the primary auxiliary circuit is connected to the enthalpy injection port 113; a secondary economizer 140 includes a secondary main circuit and a secondary auxiliary circuit, the inlet of the secondary main circuit is connected to the outlet of the primary main circuit, the outlet of the secondary main circuit is connected to the intake port 112 through an outdoor heat exchanger 150, the inlet of the secondary auxiliary circuit is connected to the outlet of the secondary main circuit through a second expansion valve 141, and the outlet of the secondary auxiliary circuit is connected to the intake port 112.

[0049] According to the first aspect of the present invention, a two-stage enthalpy heat pump water heating system 100 is provided. The enthalpy compressor 110 discharges compressed, high-temperature, high-pressure gaseous refrigerant from the exhaust port 111 to the inlet of a water tank 120 equipped with a heat exchange coil 121. The gaseous refrigerant enters the water tank 120 through the inlet 122 of the heat exchange coil 121, releasing heat and raising the water temperature in the tank 120. The refrigerant, after releasing heat, flows out from the outlet 123 of the heat exchange coil 121 to the inlet of the primary main circuit of the primary economizer 130. After heat exchange in the primary economizer 130, the refrigerant flows from the primary... The refrigerant is output from the outlet of the primary main circuit of the economizer 130; when the first expansion valve 131 is not open, the refrigerant is output to the inlet of the secondary main circuit of the secondary economizer 140 and enters the secondary economizer 140; when the first expansion valve 131 is open, part of the refrigerant is output to the inlet of the secondary main circuit of the secondary economizer 140 and enters the secondary economizer 140, while the other part of the refrigerant flows through the first expansion valve 131 to the inlet of the primary auxiliary circuit of the primary economizer 130, and enters the primary economizer 130 from the inlet of the primary auxiliary circuit, and is then drawn in by the throttling of the primary economizer 130. The refrigerant increases the enthalpy difference and heating capacity through heat exchange, achieving a first-stage enthalpy increase. This results in excellent heating and energy-saving performance. The refrigerant then flows from the outlet of the first-stage auxiliary circuit to the enthalpy injection port 113 of the enthalpy injection compressor 110, returning to the compressor through port 113. After heat exchange in the second-stage economizer 140, the refrigerant exits from the outlet of the second-stage main circuit. With the second expansion valve 141 closed, the refrigerant flows through the outdoor heat exchanger 150 to the suction port 112, returning to the compressor. With the second expansion valve 141 open... Below, a portion of the refrigerant flows through the outdoor heat exchanger 150 to the suction port 112, and then returns to the injection enthalpy compressor 110. The other portion of the refrigerant flows through the second expansion valve 141 to the inlet of the secondary auxiliary circuit of the secondary economizer 140. It enters the secondary economizer 140 from the inlet of the secondary auxiliary circuit. Through the throttling and heat absorption effect of the secondary economizer 140, the enthalpy difference is further increased, thereby increasing the heating capacity and achieving secondary enthalpy enhancement, thus enhancing the heating effect and energy saving effect. Then, the refrigerant flows out from the outlet of the secondary auxiliary circuit to the suction port 112 and returns to the injection enthalpy compressor 110. This invention, through the installation of a primary economizer 130 and a secondary economizer 140 in a two-stage enthalpy heat pump water heating system 100, achieves primary and secondary enthalpy increases, thereby improving the ultra-low temperature heating capacity of the heat pump water heating system 100. This results in excellent heating and energy-saving performance. Furthermore, by controlling the on / off states of the first expansion valve 131 and the second expansion valve 141, different heating demands can be met, making the heat pump water heating system 100 suitable for various application scenarios. In other words, this invention can be applied to different application scenarios and offers excellent heating and energy-saving performance.

[0050] It should be noted that when the heat pump water heating system 100 is operating in heating mode, with the first expansion valve 131 open, the refrigerant flows from the outlet of the primary auxiliary circuit to the injection enthalpy port 113 of the injection enthalpy compressor 110, and returns to the injection enthalpy compressor 110 through the injection enthalpy port 113, thereby increasing the intake volume of the injection enthalpy compressor 110 and thus improving the compression capacity of the injection enthalpy compressor 110, which is beneficial to improving the heating capacity of the heat pump water heating system 100.

[0051] It should be noted that during heating, the secondary auxiliary circuit of the secondary economizer 140 is equivalent to being connected in parallel with the outdoor heat exchanger 150, which can share the load of the outdoor heat exchanger 150, allowing the outdoor heat exchanger 150 to complete the evaporation of the refrigerant with a smaller evaporation area.

[0052] It is worth noting that, compared to the general method of supplementing heating with electric heating devices, the embodiment of the present invention achieves better energy-saving effect by adding a first-stage economizer 130 and a second-stage economizer 140 to realize two-stage enthalpy enhancement. In addition, compared to increasing the compressor operating frequency, the added first-stage economizer 130 and second-stage economizer 140 in the two-stage enthalpy heat pump water heating system 100 of the present invention are not limited by the maximum frequency of the compressor, and have better performance in terms of heating effect and low noise. In addition, compared to increasing the size of the outdoor unit heat exchanger, the added first-stage economizer 130 and second-stage economizer 140 of the present invention are more compact in structure, can be applied to a wider range of installation scenarios, and have strong versatility. Furthermore, compared to the method of using a large displacement compressor that is limited by the minimum frequency and minimum suction pressure, the embodiment of the present invention, by adding the mutually cooperating first-stage economizer 130 and second-stage economizer 140, is more energy-efficient under low load, has stronger ultra-low temperature heating capacity, and better adaptability.

[0053] In one embodiment of the present invention, reference is made to... Figure 2 The heat pump water heating system 100 also includes a four-way valve 160, which is connected to the exhaust port 111, the intake port 112, the inlet 122 of the heat exchange coil 121, and the outdoor heat exchanger 150. By controlling the on / off state of the four-way valve 160, the flow direction of the refrigerant can be changed, which is beneficial to establishing a reliable refrigerant circuit in the heat pump water heating system 100, making the refrigerant circulation more complete, improving system performance, and achieving better heating and energy-saving effects.

[0054] Reference Figure 2 The heat pump water heating system 100 also includes a gas-liquid separator 170, which is located between the compressor's suction port 112 and the four-way valve 160. The output end of the gas-liquid separator 170 is connected to the compressor's suction port 112, and the input end of the gas-liquid separator 170 is connected to the four-way valve 160 and the outlet of the secondary auxiliary circuit, respectively.

[0055] Specifically, when the heat pump water heating system 100 is operating in heating mode, with the second expansion valve 141 open, a portion of the refrigerant flows through the outdoor heat exchanger 150 and the four-way valve 160 to the input end of the gas-liquid separator 170; the other portion of the refrigerant flows through the second expansion valve 141 to the inlet of the secondary auxiliary circuit of the secondary economizer 140, enters the secondary economizer 140 from the inlet of the secondary auxiliary circuit, and then flows out from the outlet of the secondary auxiliary circuit to the input end of the gas-liquid separator 170; the two portions of refrigerant that are split at the outlet of the secondary main circuit flow back to the gas-liquid separator 170 after passing through different refrigerant circuits. After the gas-liquid separation effect of the gas-liquid separator 170, the refrigerant returns to the injection enthalpy compressor 110 through the suction port 112, increasing the suction volume of the injection enthalpy compressor 110, thereby improving the compression capacity of the injection enthalpy compressor 110, which is beneficial to improving the heating capacity of the heat pump water heating system 100. In addition, by setting up a gas-liquid separator 170 to separate gaseous and liquid refrigerant, the operational safety and reliability of the injection enthalpy compressor 110 are ensured to a certain extent.

[0056] Reference Figure 2 The heat pump water heating system 100 also includes: an exhaust temperature sensor 180, a water tank inlet temperature sensor 181, a water tank outlet temperature sensor 182, a first temperature sensor 183, and a second temperature sensor 184.

[0057] Among them, the exhaust temperature sensor 180 is set between the enthalpy compressor 110 and the four-way valve 160 to collect the refrigerant temperature Tp at the exhaust port of the high-temperature and high-pressure refrigerant output by the enthalpy compressor 110; the water tank inlet temperature sensor 181 is set at the inlet 122 of the heat exchange coil 121 to collect the inlet refrigerant temperature Tin at the inlet of the heat exchange coil 121; the water tank outlet temperature sensor 182 is set at the outlet 123 of the heat exchange coil 121 to collect the outlet refrigerant temperature Tout at the outlet of the heat exchange coil 121; the first temperature sensor 183 is set at the inlet of the primary auxiliary circuit to collect the inlet temperature T1a of the primary auxiliary circuit; and the second temperature sensor 184 is set at the outlet of the primary auxiliary circuit to collect the outlet temperature T1b of the primary auxiliary circuit. By setting multiple temperature sensors to collect the refrigerant temperature at multiple locations in the heat pump water heating system 100, a reliable data basis is provided for the subsequent control of the opening and closing states of the first expansion valve 131 and the second expansion valve 141.

[0058] Those skilled in the art will understand that the system structure shown in the figures does not constitute a limitation on the embodiments of the present invention, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0059] It will be understood by those skilled in the art that the system architecture and application scenarios described in the embodiments of the present invention are for the purpose of more clearly illustrating the technical solutions of the embodiments of the present invention, and do not constitute a limitation on the technical solutions provided in the embodiments of the present invention. It will be known by those skilled in the art that, with the evolution of system architecture and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present invention are also applicable to similar technical problems.

[0060] Based on the above system architecture, various embodiments of the operation control method of the present invention are proposed below.

[0061] Reference Figure 3 , Figure 3 This is a flowchart illustrating an embodiment of the operation control method provided by the present invention, which is applied to... Figure 1 The heat pump hot water system 100 shown in this embodiment of the invention includes, but is not limited to, steps S110 and S320.

[0062] Step S310: Obtain the refrigerant superheat in the water tank and the outdoor ambient temperature. The refrigerant superheat in the water tank is obtained by subtracting the refrigerant outlet temperature from the inlet refrigerant temperature of the heat exchange coil.

[0063] Step S320: Control the opening and closing status of the first expansion valve and the second expansion valve according to the superheat of the refrigerant in the water tank and the outdoor ambient temperature.

[0064] The embodiments of the present invention employ an operation control method including steps S310 and S320, which controls the opening and closing states of the first expansion valve and the second expansion valve by the superheat of the refrigerant in the water tank and the outdoor ambient temperature, thereby meeting different heating needs and making the heat pump water heating system applicable to different application scenarios, achieving good heating and energy-saving effects.

[0065] Specifically, the inlet refrigerant temperature Tin and the outlet refrigerant temperature Tout of the heat exchange coil are obtained by the inlet temperature sensor and the outlet temperature sensor, respectively. The refrigerant superheat of the water tank is obtained by subtracting the outlet refrigerant temperature Tout from the inlet temperature Tin.

[0066] In one embodiment of the present invention, reference is made to... Figure 4 Step S320 includes, but is not limited to, step S410.

[0067] Step S410: In response to the refrigerant superheat in the water tank being less than the second set value and the outdoor ambient temperature being greater than or equal to the third set value, control the first expansion valve to close and control the second expansion valve to open.

[0068] In this embodiment of the invention, step S410 determines the relationship between the superheat of the refrigerant in the water tank and the second set value. If the superheat of the refrigerant in the water tank is less than the second set value, it can be determined that the water side temperature may be relatively high. Correspondingly, the condensing pressure in the heat pump water heating system is relatively high, and the heat transferred by the refrigerant to the water side is insufficient. In this case, it is necessary to turn on the economizer to increase the heat and enhance the heating effect of the heat pump water heating system. Furthermore, by judging the relationship between the outdoor ambient temperature and the third set value, if the outdoor ambient temperature is greater than or equal to the third set value, it can be determined that the pressure in the heat pump water heating system is high, and the exhaust temperature Tp may also be high. When the first-stage economizer is working, the refrigerant will return directly to the enthalpy compressor through the outlet of the first-stage auxiliary circuit and the injection enthalpy port. Therefore, activating the first-stage economizer will increase the system pressure, which may cause the system pressure to exceed the applicable range of the enthalpy compressor and enter the pressure protection mode, limiting the heating capacity of the heat pump water heating system, or exceeding the operating range of the enthalpy compressor and affecting the compressor's lifespan. When the second-stage economizer is working, the refrigerant returns to the gas-liquid separator after passing through the outlet of the second-stage auxiliary circuit or the outdoor heat exchanger, without increasing the system pressure. Only activating the second-stage economizer to achieve second-stage enthalpy increase is beneficial for reducing the exhaust temperature Tp and exhaust pressure. Therefore, in response to the refrigerant superheat in the water tank being less than the second set value and the outdoor ambient temperature being greater than or equal to the third set value, the first expansion valve is controlled to close, thus disconnecting the first-stage auxiliary circuit of the first-stage economizer; the second expansion valve is controlled to open, thus opening the second-stage auxiliary circuit of the second-stage economizer; by opening the second-stage economizer, second-stage enthalpy enhancement is achieved, which improves the heating effect when the heating capacity of the heat pump water heating system is insufficient. At the same time, it helps to reduce the exhaust temperature and ensure the safe use and lifespan of the enthalpy-injected compressor.

[0069] It is understood that the specific value of the second setting can be set according to the actual application scenario, and the present invention does not impose any restrictions on this.

[0070] In one embodiment of the present invention, reference is made to... Figure 5 Step S320 includes, but is not limited to, step S510.

[0071] Step S510: In response to the refrigerant superheat in the water tank being less than the second set value and the outdoor ambient temperature being less than the third set value, control the first expansion valve and the second expansion valve to open.

[0072] In this embodiment of the invention, step S510 determines the relationship between the superheat of the refrigerant in the water tank and a second set value. If the superheat of the refrigerant in the water tank is less than the second set value, it can be determined that the heat transferred by the refrigerant to the water side is insufficient. In this case, the economizer needs to be activated to increase the heat output and enhance the heating effect of the heat pump water heating system. Further, the relationship between the outdoor ambient temperature and a third set value is determined. If the outdoor ambient temperature is less than the third set value, it can be determined that the outdoor ambient temperature is not high. In this case, activating only the secondary economizer is insufficient to improve the heating capacity; both the primary and secondary economizers need to be activated simultaneously to achieve dual-stage enthalpy enhancement, thereby effectively enhancing the heating capacity. Therefore, in response to the refrigerant superheat in the water tank being less than the second set value and the outdoor ambient temperature being less than the third set value, the first and second expansion valves are opened, connecting the primary auxiliary circuit of the primary economizer and the secondary auxiliary circuit of the secondary economizer. This dual-stage enthalpy enhancement achieves primary enthalpy increase by activating the primary economizer and secondary enthalpy increase by activating the secondary economizer, effectively enhancing the heating effect of the heat pump water heating system in ultra-low temperature scenarios. Furthermore, in ultra-low temperature scenarios, the return gas volume is increased, and the compression ratio is reduced, which helps ensure the reliable operation of the compressor.

[0073] In one embodiment of the present invention, reference is made to... Figure 6 Step S320 includes, but is not limited to, step S610.

[0074] Step S610: In response to the water tank refrigerant superheat being greater than or equal to the second set value and less than the first set value, and the outdoor ambient temperature being greater than or equal to the third set value, control the first expansion valve and the second expansion valve to close; the first set value is greater than the second set value.

[0075] In this embodiment of the invention, step S610 determines that the heat exchange temperature difference is within a reasonable range when the refrigerant superheat in the water tank is greater than or equal to a second set value and less than a first set value. Furthermore, if the ambient temperature of the heat pump water heating system is greater than or equal to a third set value, it indicates that the ambient temperature is high and the heating capacity of the heat pump water heating system itself is sufficient, eliminating the need to activate the primary and secondary economizers for enthalpy increase. Therefore, in response to the refrigerant superheat in the water tank being greater than or equal to the second set value and less than the first set value, and the outdoor ambient temperature being greater than or equal to the third set value, the first and second expansion valves are closed, disconnecting the primary and secondary auxiliary circuits, and preventing the activation of the primary and secondary economizers, effectively achieving energy savings.

[0076] Specifically, the third set value generally refers to 30 degrees Celsius or above. In this embodiment of the invention, the specific value of the third set value is not limited.

[0077] It is understood that the specific value of the first setting can be set according to the actual application scenario; as long as the second setting value is less than the first setting value, the embodiments of the present invention do not impose any restrictions on this.

[0078] In one embodiment of the present invention, reference is made to... Figure 7 Step S320 includes, but is not limited to, step S710.

[0079] Step S710: In response to the water tank refrigerant superheat being greater than or equal to the second set value and less than the first set value, and the outdoor ambient temperature being greater than or equal to the fourth set value and less than the third set value, control the first expansion valve to open and control the second expansion valve to close; the third set value is greater than the fourth set value.

[0080] In this embodiment of the invention, through step S710, if the superheat of the refrigerant in the water tank is greater than or equal to the second set value and less than the first set value, it can be determined that the heat exchange temperature difference is within a reasonable range. Furthermore, if the outdoor ambient temperature is greater than or equal to the fourth set value and less than the third set value, the ambient temperature is low, and the heating capacity of the heat pump water heating system decreases slightly. It is only necessary to control the first expansion valve to open, conduct the primary auxiliary circuit, control the second expansion valve to close, and disconnect the secondary auxiliary circuit; and activate the primary economizer to enhance the heating effect through primary enthalpy enhancement.

[0081] Specifically, the fourth setting value generally refers to 3 to 5 degrees Celsius.

[0082] In one embodiment of the present invention, reference is made to... Figure 8 Step S320 includes, but is not limited to, step S810.

[0083] Step S810: In response to the water tank refrigerant superheat being greater than or equal to the second set value and less than the first set value, and the outdoor ambient temperature being less than the fourth set value, control the first expansion valve and the second expansion valve to open.

[0084] According to an embodiment of the present invention, when the superheat of the refrigerant in the water tank is greater than or equal to the second set value and less than the first set value, it can be determined that the heat exchange temperature difference is within a reasonable range. Furthermore, when the outdoor ambient temperature is less than the fourth set value, the evaporation temperature of the heat exchanger is low, and the heat exchanger may frost over, affecting the heat exchange effect. In this case, the first expansion valve and the second expansion valve are opened, and the first-stage economizer and the second-stage economizer are opened at the same time to significantly improve the low-temperature heating capacity of the system and maintain a good heating effect.

[0085] In one embodiment of the present invention, step S320 is further described, which may include, but is not limited to, the following steps: in response to the superheat of the refrigerant in the water tank being greater than or equal to a first set value, controlling the first expansion valve and the second expansion valve to close.

[0086] Specifically, if the refrigerant superheat in the water tank is greater than or equal to the first set value, it indicates that the refrigerant is delivering insufficient heat to the water for heating, resulting in poor heat exchange in the heat exchange coils of the water tank, thus indicating an abnormality in the heat pump water heating system. Possible system abnormalities include insufficient refrigerant charge or insufficient refrigerant entering the water tank. In this case, it is necessary to close the first and second expansion valves, and shut down the primary and secondary economizers to facilitate troubleshooting the cause of the system malfunction.

[0087] In one embodiment of the present invention, the operation control method further includes: adjusting the opening of the first expansion valve according to the first-stage superheat so that the first-stage superheat falls within a first set range; the first-stage superheat is obtained by subtracting the inlet temperature from the outlet temperature of the first-stage auxiliary circuit. Specifically, the first-stage superheat can be obtained by subtracting the inlet temperature T1a from the outlet temperature T1b of the first-stage auxiliary circuit. Adjusting the opening of the first expansion valve to keep the first-stage superheat within the first set range helps to ensure the safe and reliable operation of the compressor, as well as the compression capacity of the injection enthalpy compressor.

[0088] In one embodiment of the present invention, reference is made to... Figure 9 The steps “adjusting the opening of the first expansion valve according to the first-level superheat” include, but are not limited to, steps S910 and S920.

[0089] Step S910: When the first-stage superheat is greater than the upper limit of the first set range, increase the opening of the first expansion valve.

[0090] Step S920: When the first-stage superheat is less than the lower limit of the first set range, reduce the opening of the first expansion valve.

[0091] In this embodiment of the invention, through steps S910 and S920, if the first-stage superheat is greater than the upper limit of the first set range, it is determined that the enthalpy flow rate of the refrigerant returning to the enthalpy injection port through the first-stage economizer is small. At this time, it is necessary to increase the opening of the first expansion valve to increase the enthalpy flow rate, improve the suction volume of the enthalpy injection compressor, and thus improve the compression capacity of the enthalpy injection compressor. If the first-stage superheat is less than the lower limit of the first set range, it is determined that the first-stage superheat is insufficient, which is prone to liquid return. At this time, it is necessary to reduce the opening of the first expansion valve to ensure the safe and reliable operation of the enthalpy injection compressor.

[0092] Specifically, the first set range can be 3 to 7 degrees Celsius. It is understood that the first set range can be set according to the actual application scenario, and this embodiment of the invention does not impose any limitations on it.

[0093] In one embodiment of the present invention, the opening of the second expansion valve is adjusted according to the exhaust superheat to ensure that the secondary superheat falls within a second set range; the exhaust superheat is obtained by subtracting the water temperature in the water tank from the refrigerant temperature at the exhaust port. Specifically, the exhaust superheat can be obtained by subtracting the water temperature Twater in the water tank from the refrigerant temperature Tp at the exhaust port; adjusting the opening of the second expansion valve to ensure that the exhaust superheat is within the second set range helps to ensure the safe and reliable operation of the compressor, as well as the compression capacity of the enthalpy-injecting compressor.

[0094] In one embodiment of the present invention, reference is made to... Figure 10 The steps “adjusting the opening of the second expansion valve according to the exhaust superheat” include, but are not limited to, steps S1010 and S1020.

[0095] Step S1010: When the exhaust superheat is greater than the upper limit of the second set range, increase the opening of the second expansion valve.

[0096] Step S1020: When the exhaust superheat is less than the lower limit of the second set range, reduce the opening of the second expansion valve.

[0097] In this embodiment of the invention, through steps S1010 and S1020, when the exhaust superheat is greater than the upper limit of the second set range, the refrigerant flow rate returning to the suction port through the secondary economizer is relatively small. At this time, it is necessary to increase the opening of the second expansion valve to increase the refrigerant flow rate, thereby increasing the suction volume of the enthalpy injection compressor and thus improving the compression capacity of the enthalpy injection compressor. When the exhaust superheat is less than the lower limit of the second set range, it indicates that the secondary superheat is insufficient, which can easily cause liquid return. It is necessary to reduce the opening of the second expansion valve to ensure the safe and reliable operation of the enthalpy injection compressor.

[0098] Specifically, the second set range can be 15 to 25 degrees Celsius. It is understood that the second set range can be set according to the actual application scenario, and this embodiment of the invention does not impose any limitations on it.

[0099] In summary, the operation control method provided by the embodiments of the present invention can achieve full-scenario application by controlling the added primary and secondary economizers, achieving good heating and energy-saving effects; it can also increase the return gas volume and reduce the compression ratio in ultra-low temperature scenarios, which is beneficial to ensuring the operation safety and reliability of the compressor; and it also expands the low-temperature application range of heat pump water heating systems, overcoming the problem of poor water heating effect due to excessively low evaporation temperature at low temperatures, making its application scenarios more extensive.

[0100] Reference Figure 11The control and operation device 1100 includes: a memory 1110, a processor 1120, and a computer program stored in the memory 1110 and executable on the processor 1120. The computer program, when running, performs the aforementioned operation control method. The processor 1120 and the memory 1110 can be connected via a bus or other means.

[0101] The memory 1110, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs, such as the operation control method described in the embodiments of the present invention. The processor 1120 implements the above-described operation control method by running the non-transitory software program and instructions stored in the memory 1110. The memory 1110 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function; the data storage area may store the execution of the above-described operation control method. In addition, the memory 1110 may include high-speed random access memory and may also include non-transitory memory, such as at least one storage device, flash memory, or other non-transitory solid-state storage device. In some embodiments, the memory 1110 may optionally include remotely located memories 1110 relative to the processor 1120, and these remote memories 1110 can be connected to the control and operation device 1100 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0102] The non-transient software program and instructions required to implement the above-described operation control method are stored in memory 1110. When executed by one or more processors 1120, the above-described operation control method is executed, for example, executing... Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 and Figure 10 The methods and steps in the text.

[0103] The operation control device provided in the third aspect embodiment of the present invention can control the opening and closing states of the first expansion valve and the second expansion valve by the superheat of the refrigerant in the water tank and the outdoor ambient temperature, thereby meeting different heating needs and making the heat pump water heating system applicable to different application scenarios, achieving good heating effect and energy saving effect.

[0104] This invention also provides a computer-readable storage medium storing computer-executable instructions for performing the aforementioned operation control method. It is understood that the computer-readable storage medium stores computer-executable instructions that are executed by one or more control processors, for example, by one processor 1120 in the aforementioned control operation device 1100, causing the processor 1120 to perform the aforementioned operation control method, for example, to execute... Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 and Figure 10 The methods and steps in the text.

[0105] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0106] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which may include computer storage media or non-transitory media and communication media or transient media. As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc DVD or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0107] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for operating and controlling a two-stage enthalpy heat pump water heating system, characterized in that, The heat pump water heating system includes an enthalpy compressor, a water tank, a primary economizer, and a secondary economizer; the enthalpy compressor includes an exhaust port, an intake port, and an enthalpy injection port; the water tank is equipped with a heat exchange coil, and the exhaust port is connected to the inlet of the heat exchange coil; the primary economizer includes a primary main circuit and a primary auxiliary circuit, the outlet of the heat exchange coil is connected to the inlet of the primary main circuit, the inlet of the primary auxiliary circuit is connected to the outlet of the primary main circuit via a first expansion valve, and the outlet of the primary auxiliary circuit is connected to the enthalpy injection port; the secondary economizer includes a secondary main circuit and a secondary auxiliary circuit, the inlet of the secondary main circuit is connected to the outlet of the primary main circuit, the outlet of the secondary main circuit is connected to the intake port via an outdoor heat exchanger, the inlet of the secondary auxiliary circuit is connected to the outlet of the secondary main circuit via a second expansion valve, and the outlet of the secondary auxiliary circuit is connected to the intake port; the method includes: The superheat of the refrigerant in the water tank and the outdoor ambient temperature are obtained. The superheat of the refrigerant in the water tank is obtained by subtracting the refrigerant temperature at the outlet of the heat exchange coil from the inlet refrigerant temperature of the heat exchange coil. The opening and closing states of the first expansion valve and the second expansion valve are controlled according to the superheat of the refrigerant in the water tank and the outdoor ambient temperature. In addition, the method also includes: In response to the refrigerant superheat in the water tank being less than a second set value and the outdoor ambient temperature being greater than or equal to a third set value, the first expansion valve is controlled to close, and the second expansion valve is controlled to open; in response to the refrigerant superheat in the water tank being less than the second set value and the outdoor ambient temperature being less than the third set value, both the first and second expansion valves are controlled to open; and / or, In response to the refrigerant superheat in the water tank being greater than or equal to a second set value and less than a first set value, and the outdoor ambient temperature being greater than or equal to a third set value, the first expansion valve and the second expansion valve are controlled to close; the first set value is greater than the second set value. In response to the refrigerant superheat in the water tank being greater than or equal to a second set value and less than a first set value, and the outdoor ambient temperature being greater than or equal to a fourth set value and less than a third set value, the first expansion valve is controlled to open, and the second expansion valve is controlled to close; the third set value is greater than the fourth set value. In response to the refrigerant superheat in the water tank being greater than or equal to a second set value and less than a first set value, and the outdoor ambient temperature being less than a fourth set value, the first expansion valve and the second expansion valve are controlled to open.

2. The control method according to claim 1, characterized in that, The opening of the first expansion valve is adjusted according to the first-stage superheat so that the first-stage superheat falls within the first set range; the first-stage superheat is obtained by subtracting the inlet temperature from the outlet temperature of the first-stage auxiliary circuit.

3. The control method according to claim 1, characterized in that, The opening of the second expansion valve is adjusted according to the exhaust superheat so that the exhaust superheat falls within the second set range; the exhaust superheat is obtained by subtracting the water temperature in the water tank from the refrigerant temperature at the exhaust port.

4. The control method according to claim 2, characterized in that, The step of adjusting the opening of the first expansion valve according to the first-stage superheat includes: increasing the opening of the first expansion valve when the first-stage superheat is greater than the upper limit of the first set range; and decreasing the opening of the first expansion valve when the first-stage superheat is less than the lower limit of the first set range.

5. The control method according to claim 3, characterized in that, The step of adjusting the opening of the two expansion valves according to the exhaust superheat includes: increasing the opening of the second expansion valve when the exhaust superheat is greater than the upper limit of the second set range; and decreasing the opening of the second expansion valve when the exhaust superheat is less than the lower limit of the second set range.

6. The control method according to claim 1, characterized in that, Also includes: In response to the superheat of the refrigerant in the water tank being greater than or equal to a first set value, the first expansion valve and the second expansion valve are controlled to close.

7. An operation control device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the operation control method as described in any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the operation control method as described in any one of claims 1 to 6.

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