Heat pump system

Abstract

The invention provides a heat pump system. The heat pump system comprises a first water tank and a second water tank; the refrigerant loop is sequentially connected with the compressor, the first heat exchanger, the first throttling element, the second heat exchanger, the second throttling element and the third heat exchanger; the control part is configured to control the opening degree of the first throttling element when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, so that the outlet supercooling degree of the first heat exchanger meets the set supercooling degree condition, and the latent heat and the sensible heat of the refrigerant are utilized for heat exchange; when the first water storage temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, the opening degree of the first throttling element can be controlled, so that the superheat degree of an outlet of the first heat exchanger meets the set superheat degree condition, and sensible heat of the refrigerant can be utilized in the first heat exchanger for heat exchange till the first water storage temperature reaches the first set water temperature; the refrigerant reference water temperature is set according to the type of refrigerant used. According to the invention, flexible and wide-range outlet water temperature can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and particularly to a heat pump system. Background Art

[0002] In the case of the increasingly serious global greenhouse effect, the requirements for the environmental performance of refrigerants in the air conditioning field are getting higher and higher. The air source heat pump (ATW, Air to Water) has attracted much attention. Consumers hope that the outlet water temperature can cover a larger range to meet the needs of different terminals of the heat pump system. For example, the outlet water with a relatively low temperature can be used for fan coil unit refrigeration, the outlet water with a medium temperature can be used for floor heating, and the outlet water with a relatively high temperature can be used for heating or providing domestic hot water. At present, the vast majority of air conditioning systems use several refrigerants such as R410A, R32, and R290. Affected by the physical properties of the refrigerants, when using R410A, the highest outlet water temperature can reach 55°C, when using R32, the highest outlet water temperature can reach 60°C, and when using R290, the highest outlet water temperature can reach 80°C. Due to the limitation of the maximum saturation pressure of different refrigerants, if the outlet water temperature is further increased, the system high-pressure protection will be triggered.

[0003] If it is desired to further increase the outlet water temperature, in the prior art, electric heating is usually used for continuous heating. The main disadvantage of electric heating is that it is not energy-saving. Or a cascade heat recovery system is used. In the cascade heat recovery system, the primary system uses a refrigerant with a relatively low critical temperature such as R410A or R32, and the secondary system uses a refrigerant with a relatively high critical temperature, R134a. In the Chinese patent application (CN108278751A), an energy-saving air conditioning system with sensible heat and latent heat dual recovery is disclosed. In the refrigeration condition, after the refrigerant comes out of the compressor 1, it enters the sensible heat recovery device 8 to heat the hot water, and then flows to the evaporator 9 through the four-way valve 3, exchanges heat with the heat transfer medium in the latent heat recovery device. After the heat transfer medium absorbs heat and evaporates, it enters the compressor two 11. After being compressed by the compressor 11, it becomes a high-temperature and high-pressure heat transfer medium, and transfers heat to the hot water in the condenser 12 to increase its temperature. After the refrigerant flows out of the evaporator 9, it flows to the indoor heat exchanger 4 through the throttling action of the throttling device 7 for indoor refrigeration, and finally returns to the compressor 1 through the gas-liquid separator 2.

[0004] It is not difficult to see that two compressors (compressor 1 and compressor 11, as Figure 1 shown) are used for secondary compression of the refrigerant in the above-mentioned comparative document. Using two compressors will significantly increase the complexity and cost of the system. Summary of the Invention

[0005] The heat pump system proposed by the present invention aims to provide outlet water covering different temperature ranges under the condition of only setting one compressor to meet the needs of different terminals of the heat pump system.

[0006] A first aspect of the present application provides a heat pump system, comprising: a first water tank and a second water tank independently arranged from each other, a refrigerant circuit, and a control unit; wherein, the refrigerant circuit includes a compressor, a first heat exchanger, a first throttling element, a second heat exchanger, a second throttling element, and a third heat exchanger connected in sequence; wherein, the water heat-exchanged with the first heat exchanger is stored in the first water tank, and the water heat-exchanged with the second heat exchanger is stored in the second water tank.

[0007] In one or more embodiments of the present application, the control unit is configured to control the opening degree of the first throttling element when the first water storage temperature of the first water tank is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature of the first water tank, so that the outlet subcooling degree of the first heat exchanger meets the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger.

[0008] In one or more embodiments of the present application, the control unit is configured to control the opening degree of the first throttling element when the first water storage temperature is higher than the refrigerant reference water temperature and lower than the first set water temperature, so that the outlet superheat degree of the first heat exchanger meets the set superheat degree condition, so as to utilize the sensible heat of the refrigerant for heat exchange in the first heat exchanger until the first water storage temperature reaches the first set water temperature.

[0009] In one or more embodiments of the present application, the refrigerant reference water temperature is set according to the type of refrigerant used.

[0010] In one or more embodiments of the present application, the control unit is further configured to infer whether the outlet subcooling degree of the first heat exchanger is higher than the set subcooling degree upper limit threshold when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, and when the outlet subcooling degree of the first heat exchanger is higher than the set subcooling degree upper limit threshold, execute the control of increasing the opening degree of the first throttling element until the outlet subcooling degree of the first heat exchanger is no longer higher than the set subcooling degree upper limit threshold.

[0011] In one or more embodiments of the present application, the control unit is further configured to infer whether the outlet subcooling degree of the first heat exchanger is lower than the set subcooling degree lower limit threshold when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, and when the outlet subcooling degree of the first heat exchanger is lower than the set subcooling degree lower limit threshold, execute the control of decreasing the opening degree of the first throttling element until the outlet subcooling degree of the first heat exchanger is no longer lower than the set subcooling degree lower limit threshold.

[0012] In one or more embodiments of the present application, the control unit is further configured to, when the first stored water temperature is higher than the refrigerant reference water temperature and the first stored water temperature is lower than the first set water temperature, be able to infer whether the superheat at the outlet of the first heat exchanger is higher than the set upper limit threshold of superheat, and when the superheat at the outlet of the first heat exchanger is higher than the set upper limit threshold of superheat, execute the control of reducing the opening degree of the first throttling element until the superheat at the outlet of the first heat exchanger is no longer higher than the set upper limit threshold of superheat.

[0013] In one or more embodiments of the present application, the control unit is further configured to, when the first stored water temperature is higher than the refrigerant reference water temperature and the first stored water temperature is lower than the first set water temperature, be able to infer whether the superheat at the outlet of the first heat exchanger is lower than the set lower limit threshold of superheat, and when the superheat at the outlet of the first heat exchanger is lower than the set lower limit threshold of superheat, execute the control of increasing the opening degree of the first throttling element until the superheat at the outlet of the first heat exchanger is no longer lower than the set lower limit threshold of superheat.

[0014] In one or more embodiments of the present application, the heat pump system further includes a bypass branch, and the bypass branch is arranged in parallel with the first throttling element; a valve element is arranged on the bypass branch.

[0015] In one or more embodiments of the present application, the control unit is further configured to, when the first stored water temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, be able to control the valve element to keep the bypass branch closed.

[0016] In one or more embodiments of the present application, the control unit is further configured to, when the first stored water temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, be able to control the valve element to keep the bypass branch open.

[0017] In one or more embodiments of the present application, the control unit is further configured to, when the first stored water temperature is not lower than the first set water temperature and the second stored water temperature of the second water tank is lower than the second set water temperature of the second water tank, be able to control the first throttling element to be at the maximum opening degree and control the valve element to keep the bypass branch open.

[0018] In one or more embodiments of the present application, the first water tank is in fluid communication with the first water circulation pipeline, and a first water pump is arranged on the first water circulation pipeline; the first water pump is configured to guide the water in the first water circulation pipeline to flow into the first heat exchanger.

[0019] In one or more embodiments of the present application, the control unit is further configured to, when the first stored water temperature is not lower than the first set water temperature and the second stored water temperature is lower than the second set water temperature, be able to control the first water pump to stop running.

[0020] In one or more embodiments of the present application, an auxiliary heating element is arranged in the first water tank.

[0021] In one or more embodiments of the present application, the second water tank is in fluid communication with the second water circulation pipeline, and a second water pump is provided on the second water circulation pipeline; the second water pump is configured to guide the water in the second water circulation pipeline into the second heat exchanger.

[0022] In one or more embodiments of the present application, the control unit is further configured to control the auxiliary element to operate, stop the compressor, keep the control valve element to shut off the bypass branch, control the first throttling element to be in the valve-closed state, control the second throttling element to be in the valve-closed state, control the first water pump to operate, and control the second water pump to stop operating when the first stored water temperature is lower than the first set water temperature and the second stored water temperature is not lower than the second set water temperature.

[0023] A second aspect of the present application provides a heat pump system, which includes a first control unit and a second control unit. In one or more embodiments of the present application, the first control unit is configured to first control the opening degree of the first throttling element when the first stored water temperature in the first water tank is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature in the first water tank, so that the outlet subcooling degree of the first heat exchanger meets the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger; and when the first stored water temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, then control the opening degree of the first throttling element so that the outlet superheat degree of the first heat exchanger meets the set superheat degree condition, and the sensible heat of the refrigerant can be utilized for heat exchange in the first heat exchanger.

[0024] In one or more embodiments of the present application, the second control unit is configured to first control the opening degree of the first throttling element when the first stored water temperature is higher than the deadband control reference water temperature but lower than the first set water temperature, so that the outlet superheat degree of the first heat exchanger meets the set superheat degree condition, and the sensible heat of the refrigerant can be utilized for heat exchange in the first heat exchanger; and when the first stored water temperature is lower than the deadband control reference water temperature and lower than the first set water temperature, then control the opening degree of the first throttling element so that the outlet subcooling degree of the first heat exchanger meets the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger.

[0025] In one or more embodiments of the present application, the refrigerant reference water temperature is set according to the type of refrigerant used, and the deadband control reference water temperature is lower than the refrigerant reference water temperature.

[0026] In one or more embodiments of the present application, the first control unit is further configured to, when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, be able to presume whether the supercooling degree at the outlet of the first heat exchanger is higher than the set upper threshold of the supercooling degree, and when the supercooling degree at the outlet of the first heat exchanger is higher than the set upper threshold of the supercooling degree, execute the control of increasing the opening degree of the first throttling element until the supercooling degree at the outlet of the first heat exchanger is no longer higher than the set upper threshold of the supercooling degree; and be able to presume whether the supercooling degree at the outlet of the first heat exchanger is lower than the set lower threshold of the supercooling degree, and when the supercooling degree at the outlet of the first heat exchanger is lower than the set lower threshold of the supercooling degree, execute the control of decreasing the opening degree of the first throttling element until the supercooling degree at the outlet of the first heat exchanger is no longer lower than the set lower threshold of the supercooling degree.

[0027] In one or more embodiments of the present application, the second control is further configured to, when the first water storage temperature is lower than the deadband control reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, be able to presume whether the supercooling degree at the outlet of the first heat exchanger is higher than the set upper threshold of the supercooling degree, and when the supercooling degree at the outlet of the first heat exchanger is higher than the set upper threshold of the supercooling degree, execute the control of increasing the opening degree of the first throttling element until the supercooling degree at the outlet of the first heat exchanger is no longer higher than the set upper threshold of the supercooling degree; and be able to presume whether the supercooling degree at the outlet of the first heat exchanger is lower than the set lower threshold of the supercooling degree, and when the supercooling degree at the outlet of the first heat exchanger is lower than the set lower threshold of the supercooling degree, execute the control of decreasing the opening degree of the first throttling element until the supercooling degree at the outlet of the first heat exchanger is no longer lower than the set lower threshold of the supercooling degree.

[0028] In one or more embodiments of the present application, the first control unit is further configured to, when the first water storage temperature is higher than the refrigerant reference water temperature and the first water storage temperature is lower than the first set water temperature, be able to presume whether the superheat degree at the outlet of the first heat exchanger is higher than the set upper threshold of the superheat degree, and when the superheat degree at the outlet of the first heat exchanger is higher than the set upper threshold of the superheat degree, execute the control of decreasing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer higher than the set upper threshold of the superheat degree; and be able to presume whether the superheat degree at the outlet of the first heat exchanger is lower than the set lower threshold of the superheat degree, and when the superheat degree at the outlet of the first heat exchanger is lower than the set lower threshold of the superheat degree, execute the control of increasing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer lower than the set lower threshold of the superheat degree.

[0029] In one or more embodiments of the present application, the first control unit is further configured to, when the first stored water temperature is higher than the dead-band control reference water temperature and the first stored water temperature is lower than the first set water temperature, presume whether the superheat at the outlet of the first heat exchanger is higher than the set upper limit threshold of superheat, and when the superheat at the outlet of the first heat exchanger is higher than the set upper limit threshold of superheat, execute the control of reducing the opening degree of the first throttling element until the superheat at the outlet of the first heat exchanger is no longer higher than the set upper limit threshold of superheat; and, presume whether the superheat at the outlet of the first heat exchanger is lower than the set lower limit threshold of superheat, and when the superheat at the outlet of the first heat exchanger is lower than the set lower limit threshold of superheat, execute the control of increasing the opening degree of the first throttling element until the superheat at the outlet of the first heat exchanger is no longer lower than the set lower limit threshold of superheat.

[0030] In the present application, a single compressor can be used, and flexible and wide-range outlet water temperatures can be achieved with two water tanks.

[0031] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become clearer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 is a schematic structural diagram of the prior art;

[0034] Figure 2 is a schematic structural diagram of the heat pump system provided by one or more embodiments of the present application;

[0035] Figure 3 is a flow chart of the heat pump system provided by one or more embodiments of the present application;

[0036] Figure 4 is a flow chart of the heat pump system provided by one or more embodiments of the present application;

[0037] Figure 5 is a flow chart of the heat pump system provided by one or more embodiments of the present application;

[0038] Figure 6 is a flow chart of the heat pump system provided by one or more embodiments of the present application;

[0039] Figure 7 is a flow chart of the heat pump system provided by one or more embodiments of the present application;

[0040] Figure 8 is a flowchart of a heat pump system provided by one or more embodiments of the present application;

[0041] Figure 9 is a flowchart of a heat pump system provided by one or more embodiments of the present application;

[0042] Figure 10 is a flowchart of a heat pump system provided by one or more embodiments of the present application;

[0043] Figure 11 is a flowchart of a heat pump system provided by one or more embodiments of the present application;

[0044] Figure 12 is a schematic structural diagram of a heat pump system provided by one or more embodiments of the present application;

[0045] Figure 13 is a schematic structural diagram of a heat pump system provided by one or more embodiments of the present application;

[0046] Figure 14 is a schematic structural diagram of a heat pump system provided by one or more embodiments of the present application;

[0047] Figure 15 is a schematic structural diagram of a heat pump system provided by one or more embodiments of the present application;

[0048] Figure 16 is a schematic control diagram of a heat pump system provided by one or more embodiments of the present application;

[0049] Figure 17 is a schematic structural diagram of a heat pump system provided by one or more embodiments of the present application;

[0050] Figure 18 is a schematic control diagram of a heat pump system provided by one or more embodiments of the present application;

[0051] In the figure: 100, refrigerant circuit; 101, compressor; 102, first heat exchanger; 103, second heat exchanger; 104, third heat exchanger; 105, first throttling element; 106, second throttling element; 107, first water tank; 108, second water tank; 109, first water circulation pipeline; 110, first circulation water pump; 111, first water make-up pipeline; 112, first water make-up valve; 113, first water supply pipeline; 114, first water outlet valve; 115, reversing valve; 116, second water make-up pipeline; 117, second water make-up valve; 118, second water supply pipeline; 119, second water outlet valve; 120, second circulation water pump; 121, second water circulation pipeline; 122, bypass branch; 123, valve element; 126, auxiliary heating element; 127, first water storage temperature sensor; 128, second water storage temperature sensor; 129, outdoor temperature sensor; 130, first heat exchanger temperature sensor; 131, first water outlet temperature sensor; 132, second heat exchanger temperature sensor; 133, second water outlet temperature sensor; 134, third heat exchanger temperature sensor; 135, outdoor fan; 136, first heat exchanger pressure sensor; 20, control unit; 30, control terminal; 40, first control unit; 50, second control unit. Detailed implementation manners

[0052] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0053] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0054] The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0055] In the description of the present application, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0056] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0057] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and the use of other materials.

[0058] Figure 1 The structural schematic diagram of the heat pump system provided by one or more specific embodiments of the present invention is shown.

[0059] The heat pump system is installed in buildings such as apartments, hotels, office buildings, and residences. In one or more embodiments of the present invention, the heat pump system is an air source heat pump. An air source heat pump (abbreviated as ASHP; also known as Air to Water, ATW) is a system that uses the heat in the air to heat or cool a building. It is a type of heat pump system. From a functional perspective, it focuses more on heating and providing hot water in an energy-saving and environmentally friendly form.

[0060] A refrigerant circuit 100 is integrated in the heat pump system. The refrigerant circuit 100 is a vapor compression refrigerant circuit 100. Specifically, a compressor 101, a first heat exchanger 102, a second heat exchanger 103, a first throttling element 105, a second throttling element 106, and a third heat exchanger 104 are sequentially connected through refrigerant pipelines to form a refrigeration cycle. The refrigerant flows in the refrigeration cycle, where the first heat exchanger 102 and the second heat exchanger 103 are mainly used to further transfer the heat provided by the refrigerant circuit 100 to a target medium (such as water), and the third heat exchanger 104 is used to absorb the heat of a heat source medium (such as air).

[0061] Both the first throttling element 105 and the second throttling element 106 can be electronic expansion valves or other forms of throttling elements.

[0062] In one or more embodiments of the present application, the refrigerant is R32 refrigerant. R32 (difluoromethane) has good heat transfer performance and has a relatively low global warming potential (GWP) compared to traditional hydrochlorofluorocarbons (HCFCs) and hydrofluorochlorocarbons (HFCs) refrigerants, and is a relatively environmentally friendly refrigerant choice. In one or more embodiments of the present application, the refrigerant can also be other refrigerants, such as R410A, R290, etc.

[0063] As Figure 1 shown, a first water tank 107 and a second water tank 108 that are independently arranged from each other are also integrated in the heat pump system. The first water tank 107 is used to provide high-temperature water, and the second water tank 108 is used to provide low-temperature water.

[0064] In one or more embodiments of the present application, the water temperature range of the high-temperature water provided by the first water tank 107 is within the range of 50°C - 80°C, and the water temperature range of the low-temperature water provided by the second water tank 108 is within the range of 20°C to 60°C.

[0065] In one or more embodiments of the present application, the water temperature range of the high-temperature water provided by the first water tank 107 is within the range of 30°C - 80°C, and the water temperature range of the low-temperature water provided by the second water tank 108 is within the range of 5°C to 60°C.

[0066] Among them, the first heat exchanger 102 is configured to perform heat exchange between the refrigerant provided by the compressor 101 and water, and the water after heat exchange is stored in the first water tank 107. The second heat exchanger 103 is configured to perform heat exchange between the refrigerant passing through the first throttling element 105 and water, and the water after heat exchange is stored in the second water tank 108.

[0067] The first water tank 107 is provided with a first water circulation pipeline 109. The first water circulation pipeline 109 can make the water stored in the first water tank 107 circulate as circulating water. A first circulation water pump 110 is arranged on the first water circulation pipeline 109. The first circulation water pump 110 can pump out the water in the first water tank 107, guide the water in the first water circulation pipeline 109 to flow into the first heat exchanger 102 and participate in the heat circulation of the refrigerant circuit 100, so as to be heated by receiving the heat transferred by the first heat exchanger 102.

[0068] In one or more embodiments of the present application, the first circulation water pump 110 can be a centrifugal pump.

[0069] The first water tank 107 is also provided with a first water replenishing pipeline 111, and the first water replenishing pipeline 111 is used for replenishing water to the first water tank 107.

[0070] The first water tank 107 is also provided with a first water supply pipeline 113, and the first water supply pipeline 113 is used for supplying water to the water using terminal.

[0071] In one or more embodiments of the present application, the water using terminal connected by the first water supply pipeline 113 can be a heating device, that is, a radiator installed along the room wall, which dissipates heat by convection and radiation; it can also be a hot water distribution system, which further distributes the hot water to various positions where hot water is used, such as in the bathroom, kitchen, and washroom; it can also be a water using terminal in other water using forms.

[0072] In one or more embodiments of the present application, a first water replenishing valve 112 is arranged on the first water replenishing pipeline 111, and the first water replenishing valve 112 can be operated manually or automatically.

[0073] In one or more embodiments of the present application, a first water outlet valve 114 is arranged on the first water supply pipeline 113, and the first water outlet valve 114 can be operated manually or automatically.

[0074] In one or more embodiments of the present application, the first water tank 107 can also be provided with a first pressure relief valve to ensure that the first water tank 107 works within a safe range.

[0075] The second water tank 108 is provided with a second water circulation pipeline 121. The second water circulation pipeline 121 can make the water stored in the second water tank 108 circulate as circulating water. A second circulation water pump 120 is arranged on the second water circulation pipeline 121. The second circulation water pump 120 can pump out the water in the second water tank 108, guide the water in the second water circulation pipeline 121 to flow into the second heat exchanger 103, and participate in the heat circulation of the refrigerant circuit 100 to transfer heat.

[0076] In one or more embodiments of the present application, the second circulation water pump 120 may be a centrifugal pump.

[0077] The second water tank 108 is also provided with a second water replenishing pipeline 116, and the second water replenishing pipeline 116 is used to replenish water into the second water tank 108.

[0078] The second water tank 108 is also provided with a second water supply pipeline 118, and the second water supply pipeline 118 is used to supply water to the water using terminal.

[0079] The water using terminal connected by the second water supply pipeline 118 may be a floor heating device, that is, a device that transfers heat by installing heating elements (such as water pipes) under the floor of a room. The heat rises from the floor, making the whole room evenly heated. The water using terminal may also be a fan coil unit, which uses the supplied water to heat or cool the air and transfer it to a specific area of the building; it may also be a water using terminal in other water using forms.

[0080] In one or more embodiments of the present application, a second water replenishing valve 117 is provided on the second water replenishing pipeline 116, and the second water replenishing valve 117 can be operated manually or automatically.

[0081] In one or more embodiments of the present application, a second water outlet valve 119 may be provided on the second water supply pipeline 118, and the second water outlet valve 119 can be operated manually or automatically.

[0082] In one or more embodiments of the present application, the second water tank 108 may also be provided with a second pressure relief valve to ensure that the second water tank 108 operates within a safe range.

[0083] The first water tank 107 and the second water tank 108 can be installed in an indoor environment such as a machine room or a mechanical room to prevent the water tanks from freezing in cold winters or overheating in extremely hot summers. They can also be installed in indoor spaces such as the basement or laundry room of a residence, which can provide relatively good environmental conditions for the equipment. The first water tank 107 and the second water tank 108 are preferably made of pressure-resistant and corrosion-resistant materials such as stainless steel and plastic materials to ensure their long-term stable operation.

[0084] In one or more embodiments of the present application, the first heat exchanger 102 may be a water-fluorine heat exchanger. The water-fluorine heat exchanger is a conventional term, specifically referring to a heat exchanger between a refrigerant and water, and the refrigerant is not limited to Freon. From a structural perspective, the first heat exchanger 102 may be a plate heat exchanger or a shell-and-tube heat exchanger. Exemplarily, when a plate heat exchanger is selected, the first water circulation pipeline 109 is in fluid communication with one of the flow channels in the plate heat exchanger, and the refrigerant pipeline in the refrigerant circuit 100 is in fluid communication with the other flow channel in the plate heat exchanger. Due to the heat conductivity of the plate heat exchanger, heat is transferred from the hot side to the cold side, and heat exchange is achieved between the two fluids. For ease of description, in the first heat exchanger 102, the flow channel through which water flows is defined as the first water flow channel, and the flow channel through which the refrigerant flows is defined as the first refrigerant flow channel.

[0085] In one or more embodiments of the present application, the second heat exchanger 103 may be a water-fluorine heat exchanger. For the definition of the water-fluorine heat exchanger, refer to the above text. From a structural perspective, the second heat exchanger 103 may be a plate heat exchanger or a shell-and-tube heat exchanger. Exemplarily, when a plate heat exchanger is selected, the second water circulation pipeline 121 is in fluid communication with one of the flow channels in the plate heat exchanger, and the refrigerant pipeline in the refrigerant circuit 100 is in fluid communication with the other flow channel in the plate heat exchanger. Due to the heat conductivity of the plate heat exchanger, heat is transferred from the hot side to the cold side, and heat exchange is achieved between the two fluids. For ease of description, in the second heat exchanger 103, the flow channel through which water flows is defined as the second water flow channel, and the flow channel through which the refrigerant flows is defined as the second refrigerant flow channel.

[0086] In one or more embodiments of the present application, at the outlet of the first flow channel, a first outlet water temperature sensor 131 for detecting the outlet water temperature is provided.

[0087] In one or more embodiments of the present application, at the outlet of the second flow channel, a second outlet water temperature sensor 132 for detecting the outlet water temperature is provided.

[0088] In one or more embodiments of the present application, the heat pump system is further provided with a first heat exchanger temperature sensor 130 for detecting the temperature of the first heat exchanger 102. Exemplarily, the first heat exchanger temperature sensor 130 may be disposed on the first refrigerant flow channel, for example, at the outlet of the first refrigerant flow channel.

[0089] In one or more embodiments of the present application, the heat pump system is further provided with a second heat exchanger temperature sensor 132 for detecting the temperature of the second heat exchanger 103. Exemplarily, the second heat exchanger temperature sensor 132 may be disposed on the second refrigerant flow channel, for example, at the outlet of the second refrigerant flow channel.

[0090] In one or more embodiments of the present application, the heat pump system is further provided with a first heat exchanger pressure sensor 137 for detecting the pressure of the first heat exchanger 102. Exemplarily, the first heat exchanger pressure sensor 137 may be disposed on the first refrigerant flow passage, for example, at the outlet of the first refrigerant flow passage.

[0091] In one or more embodiments of the present application, the heat pump system is further provided with a first water storage temperature sensor 127. The first water storage temperature sensor 127 is disposed in the first water tank 107 and is used for detecting the temperature of the water stored in the first water tank 107, that is, the first water storage temperature.

[0092] In one or more embodiments of the present application, the heat pump system is further provided with a second water storage temperature sensor 128. The second water storage temperature sensor 128 is disposed in the second water tank 108 and is used for detecting the temperature of the water stored in the second water tank 108, that is, the second water storage temperature.

[0093] The third heat exchanger 104 can exchange heat with the air guided by the outdoor fan 135, so that the refrigerant flowing in the third heat exchanger 104 undergoes a phase change from the liquid phase to the gas phase, and after the phase change, it flows back to the compressor 101. A third heat exchanger temperature sensor 134 for detecting the surface temperature of the third heat exchanger 104, that is, the coil temperature sensor, is disposed on the third heat exchanger 104, and an outdoor temperature sensor 129 for detecting the outdoor ambient temperature is also disposed.

[0094] The controller of the heat pump system is disposed in an electrical appliance with good sealing performance and heat dissipation function. The controller includes components such as a processor, a storage unit, an input / output interface, a communication interface, etc. The processor can be a dedicated processor, a central processing unit (CPU), etc. The processor can access the storage unit to execute instructions or application programs stored in the storage unit to implement related functions, such as adjusting the rotational speed of the motor driving the compressor 101 (i.e., adjusting the frequency of the compressor 101) through a program, etc. The instructions or application programs stored in the storage unit are programs disclosed in the prior art or programs compiled based on algorithms disclosed in the prior art, which are not the protected content of the present invention and will not be introduced in detail here. The storage unit can include volatile memory and / or non-volatile memory. The input / output interface can communicate with various types of sensors mentioned above to receive the detection values of various sensors. The input / output interface also communicates with devices such as the compressor 101 and the outdoor fan 135 to output control instructions generated by the processor. The communication interface can support different wireless communication protocols, such as Wi-Fi, Bluetooth, near field communication, NB-IoT, etc., to communicate with other electronic devices, including but not limited to cloud servers, computers (host computers), smart phones, tablets, PDAs, intelligent control tools, wearable devices, and vehicle-mounted devices, etc.

[0095] In one or more embodiments of the present application, the heat pump system includes a control terminal 30, and the control terminal 30 is communicatively connected to the controller. The control terminal 30 has a user-friendly interface and can be operated through a touch screen, a remote control, or other means, such as receiving a set temperature, etc. The control terminal 30 can be a centralized controller, or a combination of a centralized controller and a line controller, or can also be a computer, a tablet, a smart phone, a wearable device, etc. The control terminal 30 allows the user to input a first set water temperature of the first water tank and simultaneously input a second set water temperature of the second water tank according to requirements.

[0096] As Figure 2 shown, in one or more embodiments of the present application, the heat pump system further includes a control unit 20. The control unit 20 can be implemented by the controller. It can also be implemented by a microprocessor including a CPU and a memory and independent of the controller. In the present application, the controller is taken as an example for elaboration.

[0097] In one or more embodiments of the present application, each refrigerant corresponds to a refrigerant reference water temperature; the refrigerant reference water temperature can be obtained in an experimental environment and is an upper limit value of the water temperature. Specifically, it can be the water temperature that can be reached when the first water supply pipeline and the first make-up water pipeline are both in the off state and the water in the first water tank 107 is at the ideal water level, and the compressor raises the refrigerant to the limit saturation pressure. Exemplarily, the saturation pressure of R32 refrigerant at 60°C is 3.83 MPa. If it is desired that the water temperature is higher than 60°C, the condensation temperature of the refrigerant needs to be higher than 60°C, that is, the saturation pressure needs to be greater than 3.83 MPa. If operating under such conditions, the pressure of the refrigerant circuit will be close to the design pressure, and there is not enough design margin to further increase the saturation pressure of the refrigerant. For each refrigerant, there exists such a refrigerant reference water temperature. For example, the refrigerant reference water temperature of R32 refrigerant is 60°C, the refrigerant reference water temperature of R410A refrigerant is 55°C, and the refrigerant reference water temperature of R290 refrigerant is 80°C. In one or more embodiments of the present application, the refrigerant reference water temperature is set according to the type of refrigerant used, and the refrigerant reference water temperature is stored in the form of a set value for calling.

[0098] In one or more embodiments of the present application, the control unit 20 is configured to control the opening degree of the first throttling element 105 when the first stored water temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature of the first water tank 107, so that the outlet subcooling degree of the first heat exchanger 102 satisfies the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger 102. The set subcooling degree condition is a condition corresponding to the ideal recovered heat energy. By adjusting the outlet subcooling degree of the first heat exchanger 102, the gaseous refrigerant in the first heat exchanger 102 used as a condenser can be condensed into a saturated liquid-phase refrigerant and further cooled to make it subcooled, so that the heat energy in the first heat exchanger 102 can be more fully recovered, the energy utilization efficiency can be improved, the heat energy waste can be reduced, and higher heat transfer can be achieved on the premise of the same heat exchange area.

[0099] In one or more embodiments of the present application, the control unit 20 is configured to control the opening degree of the first throttling element 105 when the first stored water temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, so that the outlet superheat degree of the first heat exchanger 102 satisfies the set superheat degree condition, so as to utilize the sensible heat of the refrigerant for heat exchange in the first heat exchanger 102 until the first stored water temperature reaches the first set water temperature. The set superheat degree condition is such that the refrigerant in the first heat exchanger 102 remains in the gaseous state, so as to make full use of the heat transfer surface of the first heat exchanger 102, achieve higher heat exchange efficiency, and more effectively transfer heat to water to further increase the water temperature.

[0100] In the heat pump system provided by the present application, the control unit 20 can control the opening degree of the first throttling element 105 to control the outlet subcooling degree or outlet superheat degree of the first heat exchanger 102.

[0101] In one or more embodiments of the present application, when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, the control unit 20 can adjust the opening degree of the first throttling element 105 so that the outlet subcooling degree of the first heat exchanger 102 meets the set subcooling degree condition, thereby realizing heat exchange by using the latent heat and sensible heat of the refrigerant. When the first water storage temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, the control unit 20 can adjust the opening degree of the first throttling element 105 so that the outlet superheat degree of the first heat exchanger 102 meets the set superheat degree condition, and continue to use the sensible heat of the refrigerant for heat exchange until the first water storage temperature reaches the first set water temperature, thereby overcoming the limitation of the physical properties of the refrigerant on the maximum water temperature on the premise of only using one compressor and expanding the water outlet range interval of the heat pump system.

[0102] In one or more embodiments of the present application, the set subcooling degree condition is limited by a set subcooling degree upper limit threshold and a set subcooling degree lower limit threshold, that is, the outlet subcooling degree of the first heat exchanger 102 is maintained within the interval limited by the set subcooling degree upper limit threshold and the set subcooling degree lower limit threshold.

[0103] As Figure 3 shown, in one or more embodiments of the present application, the control unit 20 is further configured to, when the first water storage temperature is lower than the refrigerant reference water temperature (as shown in step S101 in Figure 3 ), and the refrigerant reference water temperature is lower than the first set water temperature (as shown in step S102 in Figure 3 ), it can be inferred whether the outlet subcooling degree of the first heat exchanger 102 is higher than the set subcooling degree upper limit threshold (as shown in step S103 in Figure 3 ), and when the outlet subcooling degree of the first heat exchanger 102 is higher than the set subcooling degree upper limit threshold, execute the control of increasing the opening degree of the first throttling element 105 until the outlet subcooling degree of the first heat exchanger 102 is no longer higher than the set subcooling degree upper limit threshold (as shown in step S104 in Figure 3 ).

[0104] Specifically, when the first water storage temperature is lower than the refrigerant reference temperature and the refrigerant reference water temperature is lower than the first set water temperature, the deviation between the first water storage temperature and the first set water temperature is large, and the sensible heat and latent heat recovery and utilization of the first heat exchanger 102 are performed. The control unit 20 obtains the temperature detection value T of the first heat exchanger temperature sensor 130 c1 and the pressure detection value of the first heat exchanger pressure sensor 136, and converts the pressure detection value of the first heat exchanger pressure sensor 136 into a saturated condensation temperature Te1 , calculate the temperature detection value T c1 and the difference between the saturation condensation temperature T e1 as the subcooling degree T at the outlet of the first heat exchanger 102 e1SC ; T e1SC = T c1 - T e1 .

[0105] Further estimate whether the subcooling degree T at the outlet of the first heat exchanger 102 e1SC is higher than the set upper threshold of subcooling degree T e1SC_max . If it is estimated that the subcooling degree T at the outlet of the first heat exchanger 102 e1SC > T e1SC_max , it means that the opening degree of the first throttling element 105 is too small, and the subcooling degree of the refrigerant in the first heat exchanger 102 is too large. Execute the control to increase the opening degree of the first throttling element 105 until the subcooling degree at the outlet of the first heat exchanger 102 is no longer higher than the set upper threshold of subcooling degree.

[0106] In one or more embodiments of the present application, the control unit 20 is further configured to when the first water storage temperature is lower than the refrigerant reference water temperature (as shown in step S201 in Figure 4 ), and when the refrigerant reference water temperature is lower than the first set water temperature (as shown in step S202 in Figure 4 ), it can be estimated whether the subcooling degree at the outlet of the first heat exchanger 102 is lower than the set lower threshold of subcooling degree (as shown in step S203 in Figure 4 ), and when the subcooling degree at the outlet of the first heat exchanger 102 is lower than the set lower threshold of subcooling degree, execute the control to decrease the opening degree of the first throttling element 105 until the subcooling degree at the outlet of the first heat exchanger 102 is no longer lower than the set lower threshold of subcooling degree (as shown in step S204 in Figure 4 ).

[0107] Further estimate whether the subcooling degree T at the outlet of the first heat exchanger 102 e1SC is lower than the set lower threshold of subcooling degree T e1SC_min . If it is estimated that the subcooling degree T at the outlet of the first heat exchanger 102 e1SC < T e1SC_min , it means that the opening degree of the first throttling element 105 is too large, and the subcooling degree of the refrigerant in the first heat exchanger 102 is too small. Execute the control to decrease the opening degree of the first throttling element 105 until the subcooling degree at the outlet of the first heat exchanger 102 is no longer lower than the set lower threshold of subcooling degree.

[0108] In one or more embodiments of the present application, control the subcooling degree at the outlet of the first heat exchanger 102 to meet the set subcooling degree condition. Exemplarily, in the interval of 1K < T e1SC < 6K, that is, T e1SC_max is 6K, and T e1sc_min is 1K.

[0109] In one or more embodiments of the present application, the set superheat condition is defined by a set superheat upper limit threshold and a set superheat lower limit threshold, that is, the superheat at the outlet of the first heat exchanger 102 is maintained within the range defined by the set superheat upper limit threshold and the set superheat lower limit threshold.

[0110] In one or more embodiments of the present application, the control unit 20 is further configured to, when the first water storage temperature is higher than the refrigerant reference water temperature (as shown in step S301 in Figure 5 ), and when the first water storage temperature is lower than the first set water temperature (as shown in step S302 in Figure 5 ), it can be inferred whether the superheat at the outlet of the first heat exchanger 102 is higher than the set superheat upper limit threshold (as shown in step S303 in Figure 5 ), and when the superheat at the outlet of the first heat exchanger 102 is higher than the set superheat upper limit threshold, the control of reducing the opening degree of the first throttling element 105 is executed until the superheat at the outlet of the first heat exchanger 102 is no longer higher than the set superheat upper limit threshold (as shown in step S304 in Figure 5 ).

[0111] Specifically, when the first water storage temperature is higher than the refrigerant reference temperature but lower than the first set water temperature, the pure sensible heat recovery of the first heat exchanger 102 is performed. The control unit 20 obtains the temperature detection value T of the first heat exchanger temperature sensor 130 c1 and the pressure detection value of the first heat exchanger pressure sensor 136, converts the pressure detection value of the first heat exchanger pressure sensor 136 into a saturated condensation temperature T e1 , calculates the difference between the temperature detection value T c1 and the saturated condensation temperature T e1 as the superheat T at the outlet of the first heat exchanger 102 e1SH ; T e1SH =T e1 -T c1 .

[0112] Further infer whether the superheat T at the outlet of the first heat exchanger 102 e1SH is higher than the set superheat upper limit threshold T e1SH_max . If it is inferred that the superheat T at the outlet of the first heat exchanger 102 e1SH >T e1SH_max , it means that the opening degree of the first throttling element 105 is too large and the superheat of the refrigerant in the first heat exchanger 102 is too large, and the control of reducing the opening degree of the first throttling element 105 is executed until the superheat at the outlet of the first heat exchanger 102 is no longer higher than the set superheat upper limit threshold.

[0113] In one or more embodiments of the present application, the control unit 20 is further configured to, when the first water storage temperature is higher than the refrigerant reference water temperature (asFigure 6 as shown in step S401), but when it is lower than the first set water temperature (e.g., Figure 6 as shown in step S402), it can be inferred whether the superheat degree at the outlet of the first heat exchanger 102 is lower than the set lower limit threshold of superheat degree (e.g., Figure 6 as shown in step S403), and when the superheat degree at the outlet of the first heat exchanger 102 is lower than the set lower limit threshold of superheat degree, the control of increasing the opening degree of the first throttling element 105 is executed until the superheat degree at the outlet of the first heat exchanger 102 is no longer lower than the set lower limit threshold of superheat degree (e.g., Figure 6 as shown in step S404).

[0114] Further infer the superheat degree T at the outlet of the first heat exchanger 102 e1SH whether it is lower than the set lower limit threshold T of superheat degree e1SH_min . If it is inferred that the superheat degree T at the outlet of the first heat exchanger 102 e1sH < T e1SH_min , it indicates that the opening degree of the first throttling element 105 is too small, and the superheat degree of the refrigerant in the first heat exchanger 102 is too small. It is necessary to prevent the phase change of the high-temperature and high-pressure gaseous refrigerant therein by adjusting the opening degree of the first throttling element 105, that is, the control of increasing the opening degree of the first throttling element 105 is executed until the superheat degree at the outlet of the first heat exchanger 102 is no longer lower than the set lower limit threshold of superheat degree.

[0115] In one or more embodiments of the present application, the superheat degree at the outlet of the first heat exchanger 102 is controlled to meet the set superheat degree condition. Exemplarily, in the range of 1K < T e1SH < 4K, that is, T e1SH_max is 4K, and T e1SH_min is 1K.

[0116] In one or more embodiments of the present application, the heat pump system further includes a bypass branch, the bypass branch is arranged in parallel with the first throttling element 105, and a valve element 123 is arranged on the bypass branch.

[0117] In one or more embodiments of the present application, the control unit 20 is further configured to control the valve element 123 to keep the bypass branch closed when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature (e.g., Figure 7 as shown in step S507).

[0118] In one or more embodiments of the present application, the control unit 20 is further configured to control the valve element 123 to keep the bypass branch open when the first water storage temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature (e.g., Figure 8 as shown in step S607).

[0119] In one or more embodiments of the present application, the control unit 20 is further configured such that when the first water storage temperature is not lower than the first set water temperature (as shown in step S701 of Figure 9 ), and the second water storage temperature of the second water tank 108 is lower than the second set water temperature of the second water tank 108 (as shown in step S702 of Figure 9 ), it can control the first throttle element 105 to be at the maximum opening degree (as shown in step S703 of Figure 9 ), and the control valve element 123 maintains the bypass branch in a conducting state (as shown in step S704 of Figure 9 ).

[0120] In one or more embodiments of the present application, the control unit 20 is further configured such that when the first water storage temperature is not lower than the first set water temperature and the second water storage temperature is lower than the second set water temperature, it can control the first water pump to stop operating (as shown in step S805 of Figure 10 ).

[0121] In one or more embodiments of the present application, an auxiliary heating element 126 is provided in the first water tank 107, and the auxiliary heating element 126 is an electric heating element.

[0122] In one or more embodiments of the present application, the control unit 20 is further configured such that when the first water storage temperature is lower than the first set water temperature and the second water storage temperature is not lower than the second set water temperature, it can control the auxiliary heating element 126 to operate (as shown in step S903 of Figure 11 ), control the compressor to shut down (as shown in step S904 of Figure 11 ), the control valve element 123 maintains the bypass branch in a shut-off state (as shown in step S905 of Figure 11 ), control the first throttle element 105 to be in a valve-closed state (as shown in step S906 of Figure 11 ), control the second throttle element 106 to be in a valve-closed state (as shown in step S907 of Figure 11 ), control the first water pump to operate (as shown in step S908 of Figure 11 ), and control the second water pump to stop operating (as shown in step S909 of Figure 11 ).

[0123] Refer to Figures 12 to 15 for a detailed introduction to different working states. In the working states as shown in Figures 12 to 15 , heating is taken as an example, that is, the reversing valve 115 (four-way valve) in the figure maintains the connection between ports D and E and the connection between ports S and C.

[0124] Figure 12Shows the operating state 1 of the heat pump system. In one or more embodiments of the present application, a low-temperature and low-pressure refrigerant enters the compressor 101, and the compressor 101 compresses it into a high-temperature and high-pressure gaseous refrigerant and discharges the compressed gaseous refrigerant. The gaseous refrigerant discharged by the compressor 101 is supplied to the first heat exchanger 102.

[0125] At this time, the first heat exchanger 102 functions as a condenser. The high-temperature and high-pressure gaseous refrigerant discharged by the compressor 101 undergoes a phase change in the first heat exchanger 102. That is, the first heat exchanger 102 acting as a condenser condenses the gaseous refrigerant supplied by the compressor 101 into a liquid phase and further subcools it. Heat is released to the first water flow passage through the condensation process. The first circulating water pump 110 operates simultaneously, causing the water in the first water circulation pipeline 109 to flow into the first water flow passage. The heat dissipation of the refrigerant raises the water temperature in the first water flow passage, and the heated water enters the first hot water storage tank 107.

[0126] The valve element (solenoid valve) 123 keeps the first bypass branch 122 shut off. The refrigerant that flows out of the first heat exchanger 102, undergoes a gas-to-liquid phase change, and is subcooled passes through the first throttling element 105. The first throttling element 105 expands the high-temperature and high-pressure liquid refrigerant condensed in the first heat exchanger 102 into a medium-temperature and medium-pressure liquid refrigerant.

[0127] The medium-temperature and medium-pressure liquid refrigerant enters the second heat exchanger 103. The second circulating water pump 120 operates simultaneously, causing the water in the second water circulation pipeline 121 to flow into the second water flow passage. The heat dissipation of the refrigerant raises the water temperature in the second water flow passage, and the heated water enters the second hot water storage tank 108.

[0128] Since the temperature of the liquid refrigerant continues to drop in the second refrigerant flow passage, that is, it is subcooled in the second heat exchanger 103. The subcooled refrigerant flows into the second throttling element 106. The second throttling element 106 expands the subcooled liquid refrigerant in the second heat exchanger 103 into a low-temperature and low-pressure two-phase refrigerant. The low-temperature and low-pressure two-phase refrigerant further enters the third heat exchanger 104. The third heat exchanger 104 operates in the evaporator state at this time, and the outdoor fan 135 operates to evaporate the expanded refrigerant and return the refrigerant in the low-temperature and low-pressure state to the compressor 101. In this process, the first heat exchanger 102 uses the latent heat and sensible heat of the refrigerant condensation to exchange heat with the water in the first hot water storage tank 107 to achieve the heating effect, and the second heat exchanger 103 uses the sensible heat of the refrigerant to exchange heat with the water in the second hot water storage tank 108 to achieve the heating effect. In the whole cycle, the heat pump system uses sensible heat and latent heat to achieve the supply of hot water.

[0129] The circulation of the refrigerant is shown by the arrow F1 in the figure.

[0130] Figure 13 Shows the operating state 2 of the heat pump system.

[0131] In one or more embodiments of the present application, the low-temperature and low-pressure refrigerant enters the compressor 101, and the compressor 101 compresses it into a high-temperature and high-pressure gaseous refrigerant and discharges the compressed gaseous refrigerant; the discharged gaseous refrigerant flows into the first heat exchanger 102, and the first heat exchanger 102 cools the high-temperature and high-pressure gaseous refrigerant to a high pressure, but a high-pressure medium-temperature gaseous refrigerant with a temperature higher than the condensation temperature. The condensation temperature refers to the temperature at which the refrigerant undergoes a phase change in the condenser, changing from a gaseous phase to a liquid phase. In this process, although no phase change occurs, heat is still released into the first water flow passage, raising the water temperature in the first water flow passage.

[0132] The valve element 123 keeps the first bypass branch 122 in a conducting state, and the high-pressure medium-temperature gaseous refrigerant flowing through the first bypass branch 122 and the first throttling element 105 remains in a gaseous state unchanged. The gaseous refrigerant enters the second heat exchanger 103, and at this time, the second heat exchanger 103 serves as a condenser. The high-pressure medium-temperature gaseous refrigerant undergoes a phase change in the second heat exchanger 103, that is, the second heat exchanger 103 serving as a condenser cools the refrigerant to a high-pressure medium-temperature liquid refrigerant.

[0133] The second throttling element 106 further expands the liquid refrigerant that has undergone a phase change in the second heat exchanger 103 into a low-temperature and low-pressure two-phase refrigerant. The low-temperature and low-pressure two-phase refrigerant further enters the third heat exchanger 104. The third heat exchanger 104 is operating in the evaporator state at this time, the outdoor fan 135 is in the operating state, the evaporator evaporates the expanded refrigerant, and returns the refrigerant in the low-temperature and low-pressure state to the compressor 101. In this process, the first heat exchanger 102 uses the sensible heat of the refrigerant to exchange heat with the water in the first hot water storage tank 107 to achieve the heating effect.

[0134] The circulation of the refrigerant is shown by the arrow F2 in the figure.

[0135] Figure 14 Shows the operating state 3 of the heat pump system.

[0136] The circulation of the refrigerant is shown by the arrow F3 in the figure.

[0137] In one or more embodiments of the present application, the low-temperature and low-pressure refrigerant enters the compressor 101, and the compressor 101 compresses it into a high-temperature and high-pressure gaseous refrigerant and discharges the compressed gaseous refrigerant. The gaseous refrigerant passes through the first heat exchanger 102. Since the first circulation water pump 110 is in a stopped state at this time, it will not cause a large fluctuation in the water temperature in the first hot water storage tank 107.

[0138] At this time, the second solenoid valve 125 keeps the second bypass branch 124 in a conducting state, and the discharged gaseous refrigerant directly flows into the second heat exchanger 103. At this time, the second heat exchanger 103 functions as a condenser, and the refrigerant in a high-temperature and high-pressure state discharged from the compressor 101 undergoes a phase change in the second heat exchanger 103. That is, the second heat exchanger 103 functioning as a condenser condenses the compressed refrigerant into a liquid phase, and the heat is released into the second water flow passage through the condensation process, raising the water temperature in the second water flow passage.

[0139] The second throttling element 106 expands the refrigerant condensed into a liquid phase into a low-temperature and low-pressure two-phase refrigerant. The low-temperature and low-pressure two-phase refrigerant further enters the third heat exchanger 104. The third heat exchanger 104 is operating in an evaporator state at this time, and the outdoor fan 135 is in an operating state. The evaporator evaporates the expanded refrigerant and returns the refrigerant in a low-temperature and low-pressure state to the compressor 101.

[0140] Exemplarily, when the water temperature in the first hot water storage tank 107 reaches the set temperature and the water temperature in the second hot water storage tank 108 is lower than the set temperature, heating can be achieved through the above process.

[0141] Figure 15 Shows the operating state 4 of the heat pump system.

[0142] In one or more embodiments of the present application, the auxiliary heating element 126 can be kept running, and the first circulation water pump 110 can be kept running. At the same time, the second circulation water pump 120, the outdoor fan 135, and the compressor 101 are all in a closed state.

[0143] Exemplarily, when the water temperature in the first hot water storage tank 107 does not reach the set temperature, but the water temperature in the second hot water storage tank 108 reaches the set temperature, heating can be achieved through the above process.

[0144] In one or more embodiments of the present application, the heat pump system includes a first control unit 40 and a second control unit 50.

[0145] In one or more embodiments of the present application, the first control unit 40 is configured to, when the first water storage temperature in the first water tank is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature in the first water tank, first control the opening degree of the first throttling element so that the outlet subcooling degree of the first heat exchanger meets the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger; and when the first water storage temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, then control the opening degree of the first throttling element so that the outlet superheat degree of the first heat exchanger meets the set superheat degree condition, and the sensible heat of the refrigerant can be utilized for heat exchange in the first heat exchanger.

[0146] In one or more embodiments of the present application, the second control unit 50 is configured to control the opening degree of the first throttling element first when the first water storage temperature is higher than the dead-band control reference water temperature but lower than the first set water temperature, so that the superheat at the outlet of the first heat exchanger meets the set superheat condition, and the sensible heat of the refrigerant can be utilized for heat exchange in the first heat exchanger; and when the first water storage temperature is lower than the dead-band control reference water temperature and lower than the first set water temperature, then control the opening degree of the first throttling element so that the subcooling at the outlet of the first heat exchanger meets the set subcooling condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger.

[0147] Wherein, the refrigerant reference water temperature is set according to the type of refrigerant used, the dead-band control reference water temperature is lower than the refrigerant reference water temperature. Exemplarily, the refrigerant reference water temperature is 60 °C, the dead-band control reference water temperature is 57 °C, and the dead-band is designed to be 3 °C.

[0148] By introducing dead-band control through the first control unit 40 and the second control unit 50, different refrigerant reference water temperatures and dead-band control reference water temperatures are sequentially given corresponding to the water temperature change directions of the first water tank and the second water tank. When the water temperature changes from low to high, the refrigerant reference water temperature is used as the control point, and when the water temperature changes from high to low, the dead-band control reference water temperature is used as the control point, so that the control point becomes an interval, avoiding frequent switching between different control strategies by the control unit when the water temperature fluctuates around a certain value, resulting in system fluctuations.

[0149] In one or more embodiments of the present application, the first control unit 40 is further configured to infer whether the subcooling at the outlet of the first heat exchanger is higher than the set subcooling upper limit threshold when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, and when the subcooling at the outlet of the first heat exchanger is higher than the set subcooling upper limit threshold, execute the control of increasing the opening degree of the first throttling element until the subcooling at the outlet of the first heat exchanger is no longer higher than the set subcooling upper limit threshold; and, infer whether the subcooling at the outlet of the first heat exchanger is lower than the set subcooling lower limit threshold, and when the subcooling at the outlet of the first heat exchanger is lower than the set subcooling lower limit threshold, execute the control of reducing the opening degree of the first throttling element until the subcooling at the outlet of the first heat exchanger is no longer lower than the set subcooling lower limit threshold.

[0150] In one or more embodiments of the present application, the second control is further configured to, when the first water storage temperature is lower than the dead-band control reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, presume whether the supercooling degree at the outlet of the first heat exchanger is higher than the set supercooling degree upper limit threshold, and when the supercooling degree at the outlet of the first heat exchanger is higher than the set supercooling degree upper limit threshold, execute the control of increasing the opening degree of the first throttling element until the supercooling degree at the outlet of the first heat exchanger is no longer higher than the set supercooling degree upper limit threshold; and presume whether the supercooling degree at the outlet of the first heat exchanger is lower than the set supercooling degree lower limit threshold, and when the supercooling degree at the outlet of the first heat exchanger is lower than the set supercooling degree lower limit threshold, execute the control of reducing the opening degree of the first throttling element until the supercooling degree at the outlet of the first heat exchanger is no longer lower than the set supercooling degree lower limit threshold.

[0151] In one or more embodiments of the present application, the first control unit 40 is further configured to, when the first water storage temperature is higher than the refrigerant reference water temperature and the first water storage temperature is lower than the first set water temperature, presume whether the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, and when the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, execute the control of reducing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer higher than the set superheat degree upper limit threshold; and presume whether the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, and when the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, execute the control of increasing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer lower than the set superheat degree lower limit threshold.

[0152] In one or more embodiments of the present application, the first control unit 40 is further configured to, when the first water storage temperature is higher than the dead-band control reference water temperature and the first water storage temperature is lower than the first set water temperature, presume whether the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, and when the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, execute the control of reducing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer higher than the set superheat degree upper limit threshold; and presume whether the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, and when the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, execute the control of increasing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer lower than the set superheat degree lower limit threshold.

[0153] In the description of the above embodiments, the specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0154] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A heat pump system, characterized in that, Comprising: A first water tank and a second water tank which are independently arranged from each other; A refrigerant circuit, which includes a compressor, a first heat exchanger, a first throttling element, a second heat exchanger, a second throttling element and a third heat exchanger connected in sequence; wherein, the water after exchanging heat with the first heat exchanger is stored in the first water tank, and the water after exchanging heat with the second heat exchanger is stored in the second water tank; and A control unit, which is configured to control the opening degree of the first throttling element when the first water storage temperature of the first water tank is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature of the first water tank, so that the outlet subcooling degree of the first heat exchanger meets the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger; when the first water storage temperature is higher than the refrigerant reference water temperature and lower than the first set water temperature, the opening degree of the first throttling element can be controlled so that the outlet superheat degree of the first heat exchanger meets the set superheat degree condition, so as to utilize the sensible heat of the refrigerant for heat exchange in the first heat exchanger until the first water storage temperature reaches the first set water temperature; Wherein, the refrigerant reference water temperature is set according to the type of refrigerant used.

2. The heat pump system according to claim 1, wherein The control unit is further configured to, when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, infer whether the outlet subcooling degree of the first heat exchanger is higher than the set subcooling degree upper limit threshold, and when the outlet subcooling degree of the first heat exchanger is higher than the set subcooling degree upper limit threshold, execute the control of increasing the opening degree of the first throttling element until the outlet subcooling degree of the first heat exchanger is no longer higher than the set subcooling degree upper limit threshold; and, it can be inferred whether the outlet subcooling degree of the first heat exchanger is lower than the set subcooling degree lower limit threshold, and when the outlet subcooling degree of the first heat exchanger is lower than the set subcooling degree lower limit threshold, execute the control of reducing the opening degree of the first throttling element until the outlet subcooling degree of the first heat exchanger is no longer lower than the set subcooling degree lower limit threshold.

3. The heat pump system according to claim 2, wherein The control unit is further configured to, when the first water storage temperature is higher than the refrigerant reference water temperature and the first water storage temperature is lower than the first set water temperature, infer whether the outlet superheat degree of the first heat exchanger is higher than the set superheat degree upper limit threshold, and when the outlet superheat degree of the first heat exchanger is higher than the set superheat degree upper limit threshold, execute the control of reducing the opening degree of the first throttling element until the outlet superheat degree of the first heat exchanger is no longer higher than the set superheat degree upper limit threshold; and, it can be inferred whether the outlet superheat degree of the first heat exchanger is lower than the set superheat degree lower limit threshold, and when the outlet superheat degree of the first heat exchanger is lower than the set superheat degree lower limit threshold, execute the control of increasing the opening degree of the first throttling element until the outlet superheat degree of the first heat exchanger is no longer lower than the set superheat degree lower limit threshold.

4. The heat pump system according to claim 3, characterized in that, Further comprising A bypass branch, the bypass branch is arranged in parallel with the first throttling element; a valve element is arranged on the bypass branch; The control unit is further configured to control the valve element to keep the bypass branch closed when the first water storage temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature; and to control the valve element to keep the bypass branch open when the first water storage temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature.

5. The heat pump system according to claim 4, wherein The control unit is further configured to control the first throttling element to be at the maximum opening degree and control the valve element to keep the bypass branch open when the first water storage temperature is not lower than the first set water temperature and the second water storage temperature of the second water tank is lower than the second set water temperature of the second water tank.

6. The heat pump system according to claim 5, wherein The first water tank is in fluid communication with a first water circulation pipeline, and a first water pump is arranged on the first water circulation pipeline; the first water pump is configured to guide the water in the first water circulation pipeline to flow into the first heat exchanger; The control unit is further configured to control the first water pump to stop operating when the first water storage temperature is not lower than the first set water temperature and the second water storage temperature is lower than the second set water temperature.

7. The heat pump system according to claim 6, wherein An auxiliary heating element is arranged in the first water tank; The second water tank is in fluid communication with a second water circulation pipeline, and a second water pump is arranged on the second water circulation pipeline; the second water pump is configured to guide the water in the second water circulation pipeline to flow into the second heat exchanger; The control unit is further configured to control the auxiliary element to operate, control the compressor to stop, control the valve element to keep the bypass branch closed, control the first throttling element to be in the valve-closed state, control the second throttling element to be in the valve-closed state, control the first water pump to operate, and control the second water pump to stop operating when the first water storage temperature is lower than the first set water temperature and the second water storage temperature is not lower than the second set water temperature.

8. A heat pump system, characterized in that, Comprising: A first water tank and a second water tank which are independently arranged from each other; A refrigerant circuit, which includes a compressor, a first heat exchanger, a first throttling element, a second heat exchanger, a second throttling element and a third heat exchanger connected in sequence; wherein, the water heat-exchanged with the first heat exchanger is stored in the first water tank, and the water heat-exchanged with the second heat exchanger is stored in the second water tank; A first control unit, which is configured to first control the opening degree of the first throttling element when the first water storage temperature of the first water tank is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature of the first water tank, so that the outlet subcooling degree of the first heat exchanger meets the set subcooling degree condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger; and to control the opening degree of the first throttling element again when the first water storage temperature is higher than the refrigerant reference water temperature but lower than the first set water temperature, so that the outlet superheat degree of the first heat exchanger meets the set superheat degree condition, and the sensible heat of the refrigerant can be utilized for heat exchange in the first heat exchanger; and The second control unit is configured to, when the first stored water temperature is higher than the differential control reference water temperature but lower than the first set water temperature, first control the opening degree of the first throttling element so that the superheat at the outlet of the first heat exchanger meets the set superheat condition, and the sensible heat of the refrigerant can be utilized for heat exchange in the first heat exchanger; and when the first stored water temperature is lower than the differential control reference water temperature and lower than the first set water temperature, then control the opening degree of the first throttling element so that the subcooling at the outlet of the first heat exchanger meets the set subcooling condition, so as to utilize the latent heat and sensible heat of the refrigerant for heat exchange in the first heat exchanger; Wherein, the refrigerant reference water temperature is set according to the type of refrigerant used, and the differential control reference water temperature is lower than the refrigerant reference water temperature.

9. The heat pump system according to claim 8, wherein the first control unit is further configured to, when the first stored water temperature is lower than the refrigerant reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, be able to infer whether the subcooling at the outlet of the first heat exchanger is higher than the set subcooling upper limit threshold, and when the subcooling at the outlet of the first heat exchanger is higher than the set subcooling upper limit threshold, execute the control of increasing the opening degree of the first throttling element until the subcooling at the outlet of the first heat exchanger is no longer higher than the set subcooling upper limit threshold; and be able to infer whether the subcooling at the outlet of the first heat exchanger is lower than the set subcooling lower limit threshold, and when the subcooling at the outlet of the first heat exchanger is lower than the set subcooling lower limit threshold, execute the control of decreasing the opening degree of the first throttling element until the subcooling at the outlet of the first heat exchanger is no longer lower than the set subcooling lower limit threshold; the second control is further configured to, when the first stored water temperature is lower than the differential control reference water temperature and the refrigerant reference water temperature is lower than the first set water temperature, be able to infer whether the subcooling at the outlet of the first heat exchanger is higher than the set subcooling upper limit threshold, and when the subcooling at the outlet of the first heat exchanger is higher than the set subcooling upper limit threshold, execute the control of increasing the opening degree of the first throttling element until the subcooling at the outlet of the first heat exchanger is no longer higher than the set subcooling upper limit threshold; and be able to infer whether the subcooling at the outlet of the first heat exchanger is lower than the set subcooling lower limit threshold, and when the subcooling at the outlet of the first heat exchanger is lower than the set subcooling lower limit threshold, execute the control of decreasing the opening degree of the first throttling element until the subcooling at the outlet of the first heat exchanger is no longer lower than the set subcooling lower limit threshold.

10. The heat pump system according to claim 9, wherein The first control unit is further configured to, when the first stored water temperature is higher than the refrigerant reference water temperature and the first stored water temperature is lower than the first set water temperature, presume whether the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, and when the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, execute the control of reducing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer higher than the set superheat degree upper limit threshold; and, presume whether the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, and when the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, execute the control of increasing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer lower than the set superheat degree lower limit threshold; The first control unit is further configured to, when the first stored water temperature is higher than the differential control reference water temperature and the first stored water temperature is lower than the first set water temperature, presume whether the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, and when the superheat degree at the outlet of the first heat exchanger is higher than the set superheat degree upper limit threshold, execute the control of reducing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer higher than the set superheat degree upper limit threshold; and, presume whether the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, and when the superheat degree at the outlet of the first heat exchanger is lower than the set superheat degree lower limit threshold, execute the control of increasing the opening degree of the first throttling element until the superheat degree at the outlet of the first heat exchanger is no longer lower than the set superheat degree lower limit threshold.

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