Control Method of Heat Pump System

Abstract

The present invention discloses a pressure buffering device and a heat pump system. The pressure buffering device includes: a buffer tank, on which a liquid inlet and a liquid outlet are provided; a flexible film, which is arranged in the buffer tank, and the flexible film divides the interior of the buffer tank into a buffer cavity and a solution cavity, and the liquid inlet and the liquid outlet are respectively communicated with the solution cavity. The pressure buffering device is used to buffer the influence of the thermal expansion and contraction of the heat exchange medium on the pipeline, so as to improve the operation reliability of the heat pump system.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pumps, and in particular, to a control method for a heat pump system. Background Art

[0002] Currently, a heat pump system is usually configured with a refrigeration circuit and a user heat exchange terminal. Among them, the refrigeration circuit generally includes a compressor, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger connected together. And the indoor heat exchanger is usually configured with a refrigerant flow channel and a medium flow channel that exchange heat with each other. During actual use, the refrigerant flow channel participates in the flow of the refrigerant in the refrigeration circuit, and the heat exchange medium flowing in the medium flow channel exchanges heat with the refrigerant flowing through the refrigerant flow channel and then flows into the user heat exchange terminal to change the indoor temperature through the user heat exchange terminal. However, during actual use, there are at least the following problems: The heat exchange medium circulating between the medium flow channel and the user heat exchange terminal is affected by thermal expansion and contraction, which will cause changes in the water pressure of the indoor pipeline. Especially after the temperature of the heat exchange medium rises, it is easy to cause the pipeline to rupture and affect the use reliability. How to design a heat pump system with high operating reliability is the technical problem to be solved by the present invention. Summary of the Invention

[0003] The present invention provides a pressure buffer device and a heat pump system, which buffer the influence of the thermal expansion and contraction of the heat exchange medium on the pipeline through the pressure buffer device to improve the operating reliability of the heat pump system.

[0004] To achieve the above technical purpose, the present invention is implemented by adopting the following technical solutions:

[0005] A pressure buffer device, comprising:

[0006] A buffer tank, which is provided with a liquid inlet and a liquid outlet;

[0007] A flexible membrane, which is arranged in the buffer tank. The flexible membrane divides the interior of the buffer tank into a buffer cavity and a solution cavity, and the liquid inlet and the liquid outlet are respectively communicated with the solution cavity.

[0008] Further, the flexible membrane is located at the upper end of the buffer tank.

[0009] Further, the buffer tank includes: a tank body, which is provided with the liquid inlet and the liquid outlet; a tank cover, which is detachably installed on the tank body; the buffer cavity is formed between the flexible membrane and the tank cover, and the solution cavity is formed between the flexible membrane and the tank body.

[0010] Further, the edge of the flexible membrane is clamped between the tank cover and the tank body.

[0011] Further, a first outward flange is provided at the upper edge of the tank body, and a second outward flange is provided at the edge of the tank cover; the edge of the flexible film is clamped between the first outward flange and the second outward flange.

[0012] Further, a plurality of first mounting holes are formed in the first outward flange, and a plurality of second mounting holes are formed in the second outward flange; bolts pass through the first mounting holes and the second mounting holes and are threadedly connected with nuts.

[0013] Further, the edge of the flexible film is bonded to the inner surface of the tank cover.

[0014] Further, a switchable air nozzle is further provided on the tank cover, and the air nozzle communicates with the buffer cavity.

[0015] Further, a phase change energy storage component is further provided in the solution cavity.

[0016] The present invention also provides a heat pump system, including a refrigeration circuit and a user heat exchange terminal. The refrigeration circuit includes a compressor, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger. A refrigerant flow channel and a medium flow channel for heat exchange with each other are arranged in the indoor heat exchanger. The compressor, the outdoor heat exchanger, the throttling device, and the refrigerant flow channel are connected in sequence. The user heat exchange terminal is connected to the medium flow channel, and further includes the above pressure buffer device; the buffer tank in the pressure buffer device is connected in series between the user heat exchange terminal and the medium flow channel.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are as follows: By arranging a flexible film in the buffer tank to form a buffer cavity and a solution cavity, during actual use, when the heat exchange medium expands and contracts due to temperature changes, the flexible film can deform under the action of the water pressure in the buffer tank to change the volumes of the buffer cavity and the solution cavity, so as to buffer the volume change of the heat exchange medium caused by temperature changes, avoid affecting the indoor pipeline and prevent the occurrence of pipeline rupture, thereby improving the operation reliability of the heat pump system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 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.

[0019] Figure 1 It is the structural schematic diagram of the embodiment of the heat pump system of the present invention;

[0020] Figure 2One of the structural schematic diagrams of the pressure buffer device in the heat pump system embodiment of the present invention;

[0021] Figure 3 Another structural schematic diagram of the pressure buffer device in the heat pump system embodiment of the present invention. Detailed implementation manners

[0022] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] As Figures 1 - 3 shown, the heat pump system of this embodiment includes a refrigeration circuit 100 and a user heat exchange terminal 200. The refrigeration circuit 100 includes a compressor 101, an outdoor heat exchanger 102, a throttling device 103 and an indoor heat exchanger 104. In the indoor heat exchanger 104, there are refrigerant flow channels (not marked) and medium flow channels (not marked) for heat exchange with each other. The compressor 101 is sequentially connected to the outdoor heat exchanger 102 and the refrigerant flow channel through a four-way valve 105. A throttling device 103 is connected between the outdoor heat exchanger 102 and the refrigerant flow channel. The user heat exchange terminal 200 is connected to the medium flow channel. Among them, the physical entity of the user heat exchange terminal 200 can adopt a radiator or a fan coil unit, etc. In order to accelerate the circulation of the heat exchange medium between the user heat exchange terminal 200 and the medium flow channel, a circulation pump 201 is usually configured. In addition, the indoor heat exchanger 104 usually adopts a plate heat exchanger or a shell-and-tube heat exchanger. The above structural configuration is the configuration method of a conventional heat pump system, which will not be elaborated and limited here.

[0024] In order to meet the requirement of reducing the impact on the indoor pipeline caused by the thermal expansion and contraction of the heat exchange medium, the heat pump system of this embodiment is also configured with a pressure buffer device 300; the pressure buffer device 300 includes a buffer tank 1 and a flexible membrane 2. An inlet 11 and an outlet 12 are provided on the buffer tank 1; the flexible membrane 2 is arranged in the buffer tank 1. The flexible membrane 2 divides the inside of the buffer tank 1 into a buffer cavity B and a solution cavity A. The inlet 11 and the outlet 12 are respectively communicated with the solution cavity. The buffer tank 1 is connected in series between the user heat exchange terminal 200 and the medium flow channel through the inlet 11 and the outlet 12.

[0025] Specifically, during the actual operation of the heat pump system, the refrigerant in the refrigeration circuit 100 circulates, and there is a circulating flow of the heat exchange medium between the user heat exchange terminal 200 and the indoor heat exchanger 104. The heat exchange medium and the refrigerant then conduct heat exchange in the indoor heat exchanger 104. In the winter heating mode, the temperature of the heat exchange medium is relatively high, causing the heat exchange medium to expand in volume. After the heat exchange medium expands due to temperature increase, it will increase the liquid pressure in the solution cavity A of the buffer tank 1, and the flexible membrane 2 will deform under the action of the liquid pressure to buffer the impact of the volume expansion of the heat exchange medium on the pipeline.

[0026] Among them, in order to ensure the smooth flow of the heat exchange medium in the buffer tank 1, the flexible membrane 2 can be arranged at the upper end of the buffer tank 1. In this way, the buffer medium flows below the flexible membrane 2. During the flow of the heat exchange medium, the flexible membrane 2 has less influence on the flowing heat exchange medium. At the same time, since the flexible membrane 2 does not need to bear the weight of the heat exchange medium, the service life of the flexible membrane 2 is extended.

[0027] Furthermore, to facilitate the assembly of the flexible membrane 2 into the buffer tank 1, the buffer tank 1 includes: a tank body 13 and a tank cover 14. An inlet 11 and an outlet 12 are provided on the tank body 13; the tank cover 14 is detachably installed on the tank body 13; the buffer cavity B is formed between the flexible membrane 2 and the tank cover 14. Correspondingly, the solution cavity A is formed in the tank body 13.

[0028] Specifically, during the actual assembly process, the flexible membrane 2 can be clamped between the tank body 13 and the tank cover 14 to complete the assembly. In this case, the edge of the flexible membrane 2 is clamped between the tank cover 14 and the tank body 13, and the edge of the flexible membrane 2 is in contact with and sealed to the tank cover 14 and the tank body 13 to form the solution cavity A and the buffer cavity B.

[0029] Since the flexible membrane 2 is made of an elastic material itself, after the flexible membrane 2 is clamped by the tank cover 14 and the tank body 13, the flexible membrane 2 can seal the connection part formed between the tank body 13 and the tank cover 14. In order to improve the sealing effect, a first outward flange (not marked) is provided on the upper edge of the tank body 13, and a second outward flange (not marked) is provided on the edge of the tank cover 14; the edge of the flexible membrane 2 is clamped between the first outward flange and the second outward flange. The first outward flange and the second outward flange cooperate to increase the contact area with the flexible membrane 2 to improve the sealing performance.

[0030] In addition, to facilitate the assembly of the tank body 13 and the tank cover 14, a plurality of first mounting holes are provided on the first outward flange, and a plurality of second mounting holes are provided on the second outward flange; bolts pass through the first mounting holes and the second mounting holes and are threadedly connected with nuts. Specifically, through the cooperation of the nuts and bolts, the first outward flange and the second outward flange can tightly clamp the flexible membrane 2.

[0031] Similarly, the flexible film 2 can also be connected to the can lid 14 by gluing, that is, the edge of the flexible film 2 is bonded to the inner surface of the can lid 14.

[0032] Preferably, in order to facilitate inflation into the buffer cavity B during assembly, a switchable air nozzle 21 is further provided on the can lid 14, and the air nozzle 21 communicates with the buffer cavity B. Specifically, after the can body 13, the can lid 14 and the flexible film 2 are assembled, air can be inflated into the buffer cavity B through the air nozzle 21 outside the buffer tank 1. Similarly, during the later use process, when the buffer cavity B deflates, gas can also be supplemented to the buffer cavity B through the air nozzle 21.

[0033] Furthermore, a phase change energy storage component 3 is further provided in the solution cavity A. Specifically, a phase change material is configured in the phase change energy storage component 3, and the phase change material can play a role in energy storage. In the winter heating mode, heat can be stored through the phase change material; while in the summer cooling mode, cold can be stored through the phase change material.

[0034] More importantly, the buffer tank 1 configured with the phase change energy storage component 3 has different functions in different modes, which are specifically described as follows.

[0035] In the summer cooling mode:

[0036] After the user heat exchange terminal 200 receives the refrigeration operation instruction, the circulation pump 201 starts, and the user heat exchange terminal 200 begins to release cold to the room. The cold water at the outlet of the circulation pump 201 enters the user heat exchange terminal 200, cools the indoor air (for example: the user heat exchange terminal 200 uses a fan coil unit to blow cold air into the room to produce an air-conditioning refrigeration effect). After that, the temperature of the heat exchange medium rises, and then it enters the indoor heat exchanger 104. If the return water temperature T of the indoor heat exchanger 104 is detected to be ≥ 13 °C (the first temperature value) at this time, the refrigeration circuit 100 starts refrigeration operation. The cold water coming out of the indoor heat exchanger 104 enters the buffer tank 1, cools and stores energy in the phase change energy storage material inside the phase change energy storage component 3 to a certain extent, then flows out of the buffer tank 1, enters the circulation pump 201, and then enters the user heat exchange terminal 200, and so on in a cycle, thus completing the refrigeration cycle of the indoor water system. During the operation of the refrigeration circuit 100, when T ≤ 10 °C (the second temperature value), the refrigeration circuit 100 stops refrigeration operation, and the circulation pump 201 continues to operate. During this process, the air-conditioning cold of the user heat exchange terminal 200 comes from the release of the stored cold in the phase change energy storage component 3 of the buffer tank 1. Since the buffer tank 1 has a certain amount of stored cold, it can provide cold for the user heat exchange terminal 200 for a long time, which reduces the start-stop times of the refrigeration circuit 100 and avoids the waste of electric energy caused by the frequent start-stop of the refrigeration circuit 100, having a good energy-saving effect. When T ≥ 13 °C, the stored cold in the buffer tank 1 has been released completely. At this time, the refrigeration circuit 100 starts refrigeration operation, and at the same time provides cold for the cold storage of the buffer tank 1 and the air cooling of the user heat exchange terminal 200 until T ≤ 10 °C, and then starts the above cycle again and again.

[0037] In the case of heating in winter:

[0038] After the user heat exchange terminal 200 receives the heating operation instruction, the circulation pump 201 starts, and the user heat exchange terminal 200 begins to operate; the hot water at the outlet of the circulation pump 201 enters the user heat exchange terminal 200, heats the indoor air, and then the water temperature decreases and enters the indoor heat exchanger 104. If the return water temperature T in the return water pipe 15 at the inlet of the indoor heat exchanger 104 is detected to be ≤ 39°C (the third temperature value) at this time, the refrigeration circuit 100 starts heating operation. The heating hot water coming out of the indoor heat exchanger 104 enters the buffer tank 1, heats and stores the phase change energy storage material inside the phase change energy storage component 3 in the buffer tank 1 to a certain extent, and then the hot water output from the buffer tank 1 enters the circulation pump 201 and then enters the user heat exchange terminal 200 to heat the indoor air, and so on in a cycle, thus completing the heating cycle of the indoor water system. When T ≥ 42°C (the fourth temperature value), the refrigeration circuit 100 stops heating operation, and the circulation pump 201 continues to operate. During this process, the heating heat of the user heat exchange terminal 200 comes from the release of the stored heat in the phase change energy storage component 3 of the buffer tank 1. Since the buffer tank 1 has a certain amount of stored heat, it can provide heat for the user heat exchange terminal 200 for a long time, which reduces the start-stop times of the refrigeration circuit 100 and avoids the waste of electric energy caused by the frequent start-stop of the refrigeration circuit 100, and has a good energy-saving effect. When T ≤ 39°C, the stored heat in the buffer tank 1 has been released completely. At this time, the refrigeration circuit 100 starts heating operation and provides heat for both the heat storage of the buffer tank 1 and the air heating of the user heat exchange terminal 200 until T ≥ 42°C, and then the above cycle starts again and again.

[0039] During the heating process, when the refrigeration circuit 100 receives a defrosting instruction, the four-way valve 105 of the refrigeration circuit 100 changes its direction. The indoor heat exchanger 104 changes from a condenser under the heating condition to an evaporator under the defrosting condition, while the outdoor heat exchanger 102 changes from an evaporator under the heating condition to a condenser under the defrosting condition. At this time, the indoor circulation pump 201 continues to operate. The phase change energy storage material in the phase change energy storage component 3 of the buffer tank 1 changes from a liquid state to a solid state to release heat. This heat first heats the indoor air through the user heat exchange terminal 200, and then enters the indoor heat exchanger 104 through the water pipeline, causing the liquid refrigerant therein to evaporate into a gas. After that, it enters the compressor 101 through the refrigerant pipeline, and is compressed by the compressor 101 into high-temperature and high-pressure refrigerant exhaust gas, which is used to defrost the outdoor heat exchanger 102. Therefore, the heat released from the buffer tank 1 provides sufficient heat for defrosting the refrigeration circuit 100, and also provides heat for maintaining the continuous heating of the user heat exchange terminal 200 during the defrosting process. This process can significantly reduce the defrosting time and maintain a relatively high air outlet temperature of the user heat exchange terminal 200. During the defrosting process, the indoor temperature can be kept stable without periodic fluctuations due to a decrease in the indoor temperature, significantly improving the user experience, especially the comfort experience. After the defrosting is completed, the four-way valve 105 of the refrigeration circuit 100 changes its direction again to restore the heating state, and at the same time provides heat for the heat storage of the buffer tank 1 and the air heating of the user heat exchange terminal 200.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a heat pump system, the heat pump system comprising a refrigeration circuit and a user heat exchange terminal, the refrigeration circuit including a compressor, an outdoor heat exchanger, a throttling device, and an indoor heat exchanger, wherein a refrigerant flow channel and a medium flow channel for heat exchange with each other are arranged in the indoor heat exchanger, the compressor, the outdoor heat exchanger, the throttling device, and the refrigerant flow channel are connected in sequence, and the user heat exchange terminal is connected to the medium flow channel, characterized in that, It also includes a pressure buffer device; the pressure buffer device includes: A buffer tank, which is provided with a liquid inlet and a liquid outlet. The buffer tank is connected in series between the user heat exchange terminal and the medium flow channel; A flexible membrane, which is arranged in the buffer tank. The flexible membrane divides the interior of the buffer tank into a buffer cavity and a solution cavity, and the liquid inlet and the liquid outlet are respectively communicated with the solution cavity; A phase change energy storage component is also arranged in the solution cavity; In the summer refrigeration mode: The circulation pump is started, and the user heat exchange terminal begins to release cold to the room. The cold water at the outlet of the circulation pump enters the user heat exchange terminal. After cooling the indoor air, the temperature of the heat exchange medium rises, and then it enters the indoor heat exchanger. If the return water temperature T of the indoor heat exchanger is detected to be ≥ the first temperature value at this time, the refrigeration circuit starts refrigeration operation; The cold water coming out of the indoor heat exchanger enters the buffer tank, cools and stores energy in the phase change energy storage material inside the phase change energy storage component to a certain extent, then flows out of the buffer tank and enters the circulation pump, and then enters the user heat exchange terminal again, so as to complete the refrigeration cycle of the indoor water system; During the operation of the refrigeration circuit, when T ≤ the second temperature value, the refrigeration circuit stops refrigeration operation, and the circulation pump continues to operate. During this process, the air-conditioning cold of the user heat exchange terminal comes from the release of the stored cold in the phase change energy storage component of the buffer tank; The second temperature value is less than the first temperature value; In the winter heating mode: The circulation pump is started, and the user heat exchange terminal begins to operate; The hot water at the outlet of the circulation pump enters the user heat exchange terminal. After heating the indoor air, the water temperature drops, and then it enters the indoor heat exchanger; If the return water temperature T in the return water pipe at the inlet of the indoor heat exchanger is detected to be ≤ the third temperature value at this time, the refrigeration circuit starts heating operation; The heating hot water coming out of the indoor heat exchanger enters the buffer tank, heats and stores energy in the phase change energy storage material inside the phase change energy storage component of the buffer tank to a certain extent, and the hot water output from the buffer tank enters the circulation pump, and then enters the user heat exchange terminal to heat the indoor air, so as to complete the heating cycle of the indoor water system; When T ≥ the fourth temperature value, the refrigeration circuit stops heating operation, and the circulation pump continues to operate. During this process, the heating heat of the user heat exchange terminal comes from the release of the stored heat in the phase change energy storage component of the buffer tank; The third temperature value is less than the fourth temperature value; During the heating process, when the refrigeration circuit receives a defrosting instruction, the four-way valve of the refrigeration circuit changes direction. The indoor heat exchanger changes from the condenser under the heating condition to the evaporator under the defrosting condition, and the outdoor heat exchanger changes from the evaporator under the heating condition to the condenser under the defrosting condition; The indoor circulation pump continues to operate, and the phase change energy storage material in the phase change energy storage component of the buffer tank changes from liquid to solid to release heat. This heat first heats the indoor air through the user heat exchange terminal, and then enters the indoor heat exchanger through the water pipeline, causing the liquid refrigerant in the indoor heat exchanger to evaporate into gas. Then it enters the compressor through the refrigerant pipeline, and is compressed by the compressor into high-temperature and high-pressure refrigerant exhaust gas to enter the outdoor heat exchanger for defrosting.

2. The control method of the heat pump system according to claim 1, characterized in that, The flexible membrane is located at the upper end of the buffer tank.

3. The control method of the heat pump system according to claim 1, characterized in that The buffer tank includes: A tank body, on which a liquid inlet and a liquid outlet are provided; A tank cover, which is detachably installed on the tank body; A buffer cavity is formed between the flexible film and the tank cover, and a solution cavity is formed between the flexible film and the tank body.

4. The control method of the heat pump system according to claim 3, characterized in that, The edge of the flexible film is clamped between the tank cover and the tank body.

5. The control method of the heat pump system according to claim 4, characterized in that, A first outward flange is provided on the upper edge of the tank body, and a second outward flange is provided on the edge of the tank cover; the edge of the flexible film is clamped between the first outward flange and the second outward flange.

6. The control method of the heat pump system according to claim 5, characterized in that A plurality of first mounting holes are provided on the first outward flange, and a plurality of second mounting holes are provided on the second outward flange; bolts pass through the first mounting holes and the second mounting holes and are threadedly connected with nuts.

7. The control method of the heat pump system according to claim 3, wherein The edge of the flexible film is bonded to the inner surface of the tank cover.

8. The control method of the heat pump system according to claim 3, characterized in that, A switchable air nozzle is further provided on the tank cover, and the air nozzle communicates with the buffer cavity.

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