Phase change heat pump system and control method thereof

Abstract

The invention relates to the technical field of water heaters, in particular to a phase change heat pump system and a control method thereof.The phase change heat pump system comprises an energy storage box, a phase change material, a condenser and a heat exchanger are arranged in the energy storage box, and the condenser and the heat exchanger are both wrapped by the phase change material; a water inlet of the heat exchanger is connected with a water supply pipeline, a water outlet of the heat exchanger is connected with a hot water output end, and the phase change material stores heat through the condenser so as to heat water in the heat exchanger into hot water. Compared with the prior art, the heat energy generated by the compressor is absorbed by the phase-change material through the condenser and stored in a latent heat form, a sensible heat storage mode of pre-storing hot water in the water storage tank is replaced, and the problem of bacterium breeding caused by long-term retention of the hot water is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of water heaters, and in particular to a phase change heat pump system and a control method thereof. Background Art

[0002] A heat pump water heater uses a compressor to heat the refrigerant, which is then heated by a condenser to heat the water in a storage tank, preserving it for the user. Currently, heat pump water heaters commonly use a storage tank to store hot water, with the appropriate tank capacity selected based on household water consumption.

[0003] However, existing heat pump water heaters rely on pre-stored hot water in water tanks. If the hot water stored in the water tank does not meet high temperature conditions and is retained for a long time, it is easy to breed bacteria (such as Legionella), resulting in water quality deterioration and posing a health hazard. Summary of the Invention

[0004] The present application provides a phase change heat pump system and a control method thereof to solve the technical problem of water quality deterioration caused by long-term retention of hot water pre-stored in a water storage tank in existing heat pump water heaters.

[0005] In the first aspect, the present application provides a phase change heat pump system, comprising an energy storage tank and a heating component, wherein the energy storage tank is provided with a phase change unit, a temperature control device, a condenser and a heat exchanger, the condenser and the heat exchanger are connected through the phase change unit, the water inlet of the heat exchanger is connected to the water supply pipeline, and the water outlet is connected to the hot water output end, the condenser is connected to the heating component, and the phase change unit and the heating component are both connected to the temperature control device, and the temperature control device controls the start and stop of the heating component by detecting the temperature of the phase change unit.

[0006] Furthermore, a box body is provided in the energy storage box, and the phase change unit is a phase change material, which is filled in the box body.

[0007] Furthermore, the heating component includes a compressor, a throttling device and an evaporator, the inlet of the condenser is connected to the outlet of the compressor, the outlet is connected to the inlet of the throttling device, the outlet of the throttling device is connected to the inlet of the evaporator, and the outlet of the evaporator is connected to the inlet of the compressor.

[0008] Furthermore, the temperature control device includes a temperature measuring probe and a controller. The temperature measuring probe is communicatively connected to the controller. A detection end of the temperature measuring probe is disposed through the box and in contact with the phase change material.

[0009] Furthermore, the heat exchanger and the condenser are both designed as coiled pipes, and a plurality of heat exchange fins are provided on the surfaces of both.

[0010] Furthermore, a cooling medium is stored in the compressor, and the cooling medium circulates in the compressor, the condenser, the throttling device and the evaporator.

[0011] Furthermore, the energy storage box also includes an outer shell, and an insulation layer is provided between the outer shell and the box body.

[0012] Furthermore, the thermal insulation layer is at least one of polyurethane foam, vacuum insulation panel and aerogel composite material.

[0013] In a second aspect, the present application further provides a control method for a phase change heat pump system, characterized in that the method comprises the following steps:

[0014] The temperature T of the phase change unit is monitored in real time by a temperature measuring probe;

[0015] When T is lower than the first set threshold value T1 preset by the controller, the compressor is started to store heat;

[0016] When T is higher than a second set threshold T2 preset by the controller, the compressor is stopped.

[0017] Furthermore, before starting the compressor to store heat, the following steps are also included:

[0018] Obtain load data for historical water use periods;

[0019] predicting water demand within a preset time period in the future based on the load data;

[0020] When the predicted water demand exceeds the set water volume, the first set threshold T1 is dynamically increased by 3-8°C.

[0021] The above technical solution provided by this application has the following advantages compared with the existing technology:

[0022] This application transforms the "static water storage" mode of the traditional water tank into a "dynamic phase change heat storage + real-time water heating" mode by directly embedding the condenser and the heat exchanger into the phase change material: on the one hand, the phase change material absorbs the heat energy generated by the compressor through the condenser and stores it in the form of latent heat, replacing the sensible heat storage method of pre-stored hot water in the water tank, avoiding the problem of bacterial growth caused by long-term retention of hot water; on the other hand, when the water in the water supply pipeline flows through the heat exchanger wrapped by the phase change material, the latent heat is quickly released through the solid-liquid phase change process to heat the cold water, realizing instant heating and use, which not only eliminates the matching contradiction between the water tank capacity and water demand, but also reduces the heat loss path from the condenser to the water tank in the traditional system through the efficient heat conduction of the phase change material, thereby improving the overall energy efficiency and response speed while ensuring water quality safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0026] Figure 1 A schematic structural diagram of a phase change heat pump system provided in an embodiment of the present application;

[0027] Figure 2 A flow chart of a control method for a phase change heat pump system provided in an embodiment of the present application Figure 1 ;

[0028] Figure 3 A schematic diagram of a control method for a phase change heat pump system provided in an embodiment of the present application Figure 2 .

[0029] Description of reference numerals:

[0030] 1. Energy storage tank; 11. Phase change unit; 12. Condenser; 13. Heat exchanger; 131. Water inlet; 132. Water outlet; 14. Box; 15. Temperature probe; 16. Housing; 17. Insulation layer;

[0031] 2. Compressor; 3. Throttling device; 4. Evaporator. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, these are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0034] For ease of description, spatially relative terms may be used herein to describe the relative position or movement of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," "above," "front," "back," and the like. Such spatially relative terms are intended to include different orientations of the device in use or operation other than the orientation depicted in the figures. For example, if the device in the figures undergoes a positional flip or a change in posture or a change in motion, then these directional indications will also change accordingly. For example, an element described as "below" or "below" another element or feature will subsequently be oriented as "above" or "above" another element or feature. Thus, the example term "below" can include both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein will be interpreted accordingly.

[0035] In order to solve the technical problem of water quality deterioration in existing heat pump water heaters due to long-term retention of hot water pre-stored in the water tank, the present application provides a phase change heat pump system and a control method thereof, which transforms the "static water storage" mode of the traditional water tank into a "dynamic phase change heat storage + real-time water heating" mode by directly embedding the condenser and the heat exchanger into the phase change material. The phase change material absorbs the heat energy generated by the compressor through the condenser and stores it in the form of latent heat, replacing the sensible heat storage method of the hot water pre-stored in the water tank, and avoiding the problem of bacterial growth caused by long-term retention of hot water.

[0036] See also Figure 1 A phase change heat pump system provided in an embodiment of the present application includes an energy storage tank 1 and a heating component. The energy storage tank 1 is provided with a phase change unit 11, a temperature control device, a condenser 12 and a heat exchanger 13. The condenser 12 and the heat exchanger 13 are connected through the phase change unit 11. The water inlet of the heat exchanger 13 is connected to the water supply pipeline, and the water outlet is connected to the hot water output end. The condenser 12 is connected to the heating component. The phase change unit 11 and the heating component are both connected to the temperature control device. The temperature control device controls the start and stop of the heating component by detecting the temperature of the phase change unit 11.

[0037] Specifically, this embodiment fills the energy storage tank 1 with a phase change unit 11, into which a condenser 12 and a heat exchanger 13 are embedded. The condenser 12 is connected to the refrigerant circulation loop in the heating component, absorbing the heat released by the refrigerant and storing it in the phase change unit 11. The heat exchanger 13 is directly connected to the water supply pipeline. When cold water flows through the heat exchanger 13, the latent heat released by the phase change unit 11 is heated in real time and output as hot water. When the system is operating, the heating component drives the refrigerant to release heat in the condenser 12. The phase change unit 11 absorbs the heat and then converts it from solid to liquid to store heat. When the user needs water, the cold water flows through the heat exchanger 13. The phase change unit 11 releases latent heat by converting from liquid to solid, heating the cold water for output. In this way, the phase change unit 11 directly wraps the condenser 12 and the heat exchanger 13, and the refrigerant releases heat and the cold water absorbs heat through the phase change unit 11, shortening the heat transfer path and reducing heat loss. At the same time, the phase change unit 11 quickly releases energy through the latent heat of phase change, which can realize instant heating of cold water without relying on pre-stored hot water, avoiding water pollution caused by water retention, and eliminating the traditional water tank structure, and can also effectively reduce the volume and occupied space of the water heater.

[0038] like Figure 1 As shown, the energy storage box 1 is further provided with a box body 14, the phase change unit 11 is a phase change material, the phase change material is filled in the box body 14, the phase change temperature of the phase change material is 40°C-60°C, and the phase change material is paraffin or hydrated salt.

[0039] Specifically, the housing 14 is made of stainless steel or corrosion-resistant aluminum alloy, with a phase change material filling chamber reserved inside. Paraffin wax (phase change temperature 40-55°C) or hydrated salt (phase change temperature 45-60°C) is injected into the housing 14 in a molten state, with a filling rate of ≥95%, completely enveloping the condenser 12 and the heat exchanger 13. Through the solid-liquid phase change characteristics of the phase change material, an automatic balance of thermal energy storage and release can be achieved within the range of 40-60°C. Among them, the 40-60°C phase change temperature accurately matches the demand for domestic hot water (45-55°C), avoiding the scaling caused by high-temperature heating (>60°C) or insufficient energy due to low-temperature heat storage (<40°C) in traditional water storage tanks.

[0040] like Figure 1 As shown, the phase change heat pump system also includes a compressor 2, a throttling device 3 and an evaporator 4. The inlet of the condenser 12 is connected to the outlet of the compressor 2, the outlet is connected to the inlet of the throttling device 3, the outlet of the throttling device 3 is connected to the inlet of the evaporator 4, and the outlet of the evaporator 4 is connected to the inlet of the compressor 2.

[0041] Specifically, in this phase-change heat pump system, compressor 2 is sequentially connected to condenser 12, throttling device 3, and evaporator 4 via refrigerant piping, forming a closed-loop cycle. Compressor 2 compresses the gaseous refrigerant to a high-temperature, high-pressure state and then delivers it to condenser 12, where the refrigerant releases heat and converts into a high-pressure liquid. After being depressurized by throttling device 3, the liquid refrigerant enters evaporator 4, absorbs heat, and vaporizes, returning to low-pressure gaseous refrigerant and returning to compressor 2, completing the cycle. Condenser 12 and evaporator 4 serve as the system's high-temperature heat release and low-temperature heat absorption ends, respectively, transferring and recycling heat energy through the refrigerant's phase change. The phase-change material within energy storage tank 1, by wrapping around condenser 12, continuously absorbs the heat energy released by the refrigerant, forming a dynamic heat storage and release mechanism. Driven by compressor 2, the refrigerant completes the full cycle of "compression-condensation-throttling-evaporation," reducing energy leakage in traditional heat pump systems and improving the overall efficiency of the heat pump.

[0042] like Figure 1 As shown, the temperature control device includes a temperature probe 15 and a controller. The temperature probe 15 is in communication with the controller. The detection end of the temperature probe 15 is passed through the box 14 and contacts the phase change material.

[0043] Specifically, the temperature measuring probe 15 penetrates into the interior of the box body 14 through a reserved hole on the side wall or top of the box body 14, and the detection end is directly inserted into the phase change material and in close contact with it. The probe body and the box body 14 are fixed with a sealing ring or welding process to ensure that there is no leakage of the phase change material; the temperature measuring probe 15 is connected to the external controller through a signal line, collects the temperature change data of the phase change material in real time, and triggers the start and stop instructions of the compressor 2 according to the preset threshold value, thereby realizing automatic control of the heat storage and release process.

[0044] like Figure 1 As shown, the heat exchanger 13 and the condenser 12 are both designed as coiled pipes, and a plurality of heat exchange fins are provided on the surfaces of both.

[0045] Specifically, the heat exchanger 13 and the condenser 12 are symmetrically distributed at the top and bottom of the box body 14, respectively. The pipes of the heat exchanger 13 and the condenser 12 adopt a spiral or serpentine coiling structure, and multiple fins are evenly welded or integrally formed on the outer surface of the pipes. The fins are corrugated or serrated to increase the surface area; the coiled pipes are arranged in multiple layers of concentric circles or parallel arrangements in the energy storage box 1 to ensure that the contact area with the phase change material is maximized. At the same time, the fins are spaced to balance the heat conduction efficiency and fluid resistance.

[0046] In an optional embodiment, a cooling medium is stored in the compressor 2 , and the cooling medium circulates in the compressor 2 , the condenser 12 , the throttling device 3 , and the evaporator 4 .

[0047] Specifically, compressor 2 stores a cooling medium (such as Freon or an environmentally friendly refrigerant) and converts it into a high-temperature, high-pressure gas through mechanical compression. The gaseous medium is piped to condenser 12, where it releases heat and condenses into a liquid. It is then depressurized and expanded into a low-temperature, low-pressure gas-liquid mixture by throttling device 3. It then enters evaporator 4, absorbs heat from the external environment, and completely vaporizes, ultimately returning to compressor 2 as a low-pressure gas, forming a closed loop. During the circulation process, the cooling medium continuously transfers and increases its thermal energy through phase changes (gas-liquid-gas).

[0048] like Figure 1 As shown, the energy storage box 1 further includes an outer shell 16 , and an insulation layer 17 is provided between the outer shell 16 and the box body 14 .

[0049] Specifically, the outer shell 16 of the energy storage box 1 is made of metal or high-strength plastic and wraps around the exterior of the box body 14, leaving an annular interlayer space between the two. The insulation layer 17 is fixed within the interlayer through foam filling, gluing, or lamination, completely covering the surface of the box body 14. It forms a tightly fitting sandwich structure with the outer shell 16 and the box body 14, preventing heat from dissipating outward through the walls of the box body 14. Furthermore, reinforcing ribs or snap-fit structures can be provided on the bottom or sides of the outer shell 16 to prevent the insulation layer 17 from deforming or falling off under pressure.

[0050] In some embodiments, the insulation layer 17 is at least one of polyurethane foam, vacuum insulation panel, and aerogel composite material.

[0051] Specifically, the selection of the insulation layer 17 meets the requirements of adaptation in multiple scenarios. Polyurethane foam is suitable for low-cost civilian equipment, vacuum insulation panels meet the requirements of ultra-thin and high efficiency, and aerogel is suitable for high-temperature or special-shaped structure scenarios.

[0052] See also Figure 2 and Figure 3 The present application also provides a control method for a phase change heat pump system. The phase change heat pump system further includes a controller (not shown in the figure), which is in communication with the temperature probe 15. Figure 2 As shown, the method includes the following steps S110-S130.

[0053] S110, monitoring the temperature T of the phase change unit 11 in real time through the temperature measuring probe 15;

[0054] S120, when T is lower than a first set threshold value T1 preset by the controller, starting compressor 2 to store heat;

[0055] S130 : When T is higher than a second set threshold value T2 preset by the controller, stop the compressor 2 .

[0056] Specifically, in this control method, the controller connects to the temperature probe 15 via a wired or wireless communication module, receiving real-time temperature data from the phase change unit 11. The controller pre-stores a first threshold value T1 and a second threshold value T2 (T2>T1). When the temperature probe 15 reports a temperature T<T1, the controller sends a start command to the compressor 2, driving the refrigerant circulation to store heat in the phase change unit 11. When T>T2, the controller shuts down the compressor 2, terminating heat storage. The threshold settings can be manually input through the controller interface or automatically adjusted based on the external environment, forming a closed-loop feedback control logic.

[0057] Furthermore, this embodiment sets T1 / T2 based on the phase change temperature range of the phase change material (solid-liquid critical point) to ensure that the heat storage process is always in the high-efficiency range, avoiding inefficient operation or excessive heat storage of the compressor 2; the compressor 2 is started only when the phase change material needs to be replenished with heat, reducing ineffective working time and reducing the overall energy consumption of the system; the T2 upper limit threshold prevents the phase change material from overheating, resulting in performance degradation or excessive pressure on the box 14, thereby extending the life of the equipment.

[0058] like Figure 3 As shown, in a more specific embodiment, before executing step S120, the process further includes executing steps S111-S113.

[0059] S111. Obtain load data for historical water use periods;

[0060] S112. Predicting water demand within a preset future time period based on load data;

[0061] S113. When the predicted water demand exceeds the set water volume, the first set threshold T1 is dynamically increased by 3-8°C.

[0062] Specifically, a water flow sensor or user habit recording module captures hot water usage data for different periods of the day or week, building a historical load database. This historical data is then trained using time series analysis or machine learning algorithms (such as LSTM neural networks) to predict peak water usage periods and demand within the next 24 hours. When the predicted demand exceeds a preset water volume (such as a household's maximum daily water consumption), the controller raises the first set threshold, T1, by 3-8°C, triggering compressor 2 to pre-store heat, ensuring the phase change material has sufficient thermal energy before the peak water usage. This method predicts water usage peaks and valleys using historical data and dynamically adjusts the heat storage threshold, avoiding the insufficient heat storage or redundant energy consumption caused by traditional fixed thresholds.

[0063] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0064] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply 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 understood as a limitation on this application.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0066] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0067] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0068] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0069] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the spirit and scope of this application. Thus, as long as these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

[0070] The above description is a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A phase change heat pump system, characterized in that: It includes an energy storage box and a heating component. The energy storage box is equipped with a phase change unit, a temperature control device, a condenser and a heat exchanger. The condenser and the heat exchanger are connected through the phase change unit. The water inlet of the heat exchanger is connected to the water supply pipeline, and the water outlet is connected to the hot water output end. The condenser is connected to the heating component. The phase change unit and the heating component are both connected to the temperature control device. The temperature control device controls the start and stop of the heating component by detecting the temperature of the phase change unit.

2. The phase change heat pump system according to claim 1, characterized in that: A box body is further provided in the energy storage box, and the phase change unit is a phase change material, which is filled in the box body.

3. The phase change heat pump system according to claim 1, characterized in that: The heating component includes a compressor, a throttling device and an evaporator. The inlet of the condenser is connected to the outlet of the compressor, the outlet is connected to the inlet of the throttling device, the outlet of the throttling device is connected to the inlet of the evaporator, and the outlet of the evaporator is connected to the inlet of the compressor.

4. The phase change heat pump system according to claim 2, characterized in that: The temperature control device includes a temperature measuring probe and a controller. The temperature measuring probe is in communication with the controller. A detection end of the temperature measuring probe is disposed through the box and in contact with the phase change material.

5. The phase change heat pump system according to claim 1, characterized in that: The heat exchanger and the condenser are both designed as coiled pipes, and a plurality of heat exchange fins are provided on the surfaces of both.

6. The phase change heat pump system according to claim 3, characterized in that: A cooling medium is stored in the compressor, and the cooling medium circulates in the compressor, the condenser, the throttling device, and the evaporator.

7. The phase change heat pump system according to claim 2, characterized in that: The energy storage box further comprises an outer shell, and an insulation layer is provided between the outer shell and the box body.

8. The phase change heat pump system according to claim 7, characterized in that: The thermal insulation layer is at least one of polyurethane foam, vacuum insulation panel and aerogel composite material.

9. A control method for a phase change heat pump system according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: The temperature T of the phase change unit is monitored in real time by a temperature measuring probe; When T is lower than the first set threshold value T1 preset by the controller, the compressor is started to store heat; When T is higher than a second set threshold T2 preset by the controller, the compressor is stopped.

10. The control method according to claim 9, characterized in that: Before starting the compressor for heat storage, the following steps are also included: Obtain load data for historical water use periods; predicting water demand within a preset time period in the future based on the load data; When the predicted water demand exceeds the set water volume, the first set threshold T1 is dynamically increased by 3-8°C.

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