A throttling device for a heat pump water heater and a control method thereof

Abstract

A throttling device for a heat pump water heater and a control method thereof include a controller, a throttling assembly, a water temperature sensor, an ambient temperature sensor, a pipe temperature sensor, and a return air temperature sensor. The throttling assembly includes a first capillary tube, a second capillary tube, and a third capillary tube. One end of the first, second, and third capillary tubes is connected to a first flow divider, and the other ends of the first, second, and third capillary tubes are connected to the second flow divider. A first solenoid valve is provided on the first capillary tube, and a second solenoid valve is provided on the second capillary tube. The water temperature sensor, ambient temperature sensor, pipe temperature sensor, return air temperature sensor, first solenoid valve, and second solenoid valve are respectively connected to the controller. The third capillary tube is in a normally open state, and the first and second capillary tubes are controlled by the on / off control of the first and second solenoid valves. The present invention makes the heat pump system more stable, energy-efficient, and efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump air conditioners, in particular to a throttling device applied to a constant-speed heat pump water heater and a control method thereof. Background Art

[0002] Currently, in the field of heat pump water heaters, the throttling device generally uses a single capillary tube or expansion valve. However, the disadvantage of a capillary tube throttling device is that it can only achieve good performance parameters at a certain operating point. However, because it is a fixed throttling method, it has a narrow range of adaptability to changes in ambient temperature and water temperature. It performs poorly at low ambient temperatures and low water temperatures, or high ambient temperatures and high water temperatures, and the system's heating capacity and energy efficiency ratio cannot reach optimal levels. The expansion valve throttling device can be adjusted according to the system's return air temperature or exhaust temperature, but the disadvantages are higher cost and more complex control. If the control is not optimized, frequent valve adjustments will lead to unstable system operation, which will in turn affect the heating capacity and energy efficiency ratio.

[0003] At present, in order to achieve good control of throttling, some of the methods are implemented by setting up multi-stage throttling devices. A two-stage compression and two-stage throttling heat pump cycle is used to perform step-by-step heating of multiple water tanks with different set temperatures through multiple mode switching; by switching different stop valves, different set temperature water tanks are heated separately in different coupling modes, and water is taken from water tanks with different set temperatures. The multi-stage throttling device has a relatively complex overall structure. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a throttling device for a heat pump water heater and a control method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A throttling device for a heat pump water heater includes a controller, a throttling assembly, a water temperature sensor, an ambient temperature sensor, a pipe temperature sensor, and a return air temperature sensor, wherein the throttling assembly, the water temperature sensor, the ambient temperature sensor, the pipe temperature sensor, and the return air temperature sensor are respectively connected to the controller, and the controller controls the on and off of the throttling assembly.

[0007] The throttling assembly includes a first capillary, a second capillary, and a third capillary. One end of the first capillary, the second capillary, and the third capillary is connected to the first diverter, and the other end of the first capillary, the second capillary, and the third capillary is connected to the second diverter. The first capillary is provided with a first solenoid valve, and the second capillary is provided with a second solenoid valve. The first solenoid valve and the second solenoid valve are both connected to a controller. The third capillary is in a normally open conduction state. The first capillary and the second capillary are controlled by the on / off of the first solenoid valve and the second solenoid valve.

[0008] The first flow splitter is connected to a first filter, and the second flow splitter is connected to a second filter.

[0009] The first capillary, the second capillary and the third capillary are arranged in parallel, and the third capillary is arranged in the middle area between the first capillary and the second capillary.

[0010] The first capillary tube, the second capillary tube, and the third capillary tube have the same inner diameter and length.

[0011] A method for controlling a throttling device of a heat pump water heater comprises the following steps:

[0012] The throttling device is applied to the heat pump water heater, which includes a fixed-speed compressor, a heat exchange coil, and a water tank. The return air temperature sensor is installed at the return air port of the fixed-speed compressor, the pipe temperature sensor is installed on the heat exchange coil, the ambient temperature sensor is installed around the heat exchange coil, and the water temperature sensor is installed on the water tank.

[0013] The heat pump water heater has an initial state, a defrost state, a hot water state, a standby state or an off state. The controller controls the opening or closing of the first solenoid valve and the second solenoid valve according to the current state of the heat pump water heater, and adjusts the conduction or closing state of the first capillary tube and the second capillary tube. The third capillary tube is always in a conducting state.

[0014] When the current operating mode is changed from shutdown or standby to hot water production, the fixed-speed compressor is considered to be in the initial state when it runs stably for 30 seconds after starting, and before the fixed-speed compressor has been running for less than 5 minutes;

[0015] Detect the water temperature T 水 ≤35℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state;

[0016] When 35℃<T 水 ≤45℃, if -12℃<T 环 ≤15℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 15℃<T 环, the third capillary tube remains in a conducting state, the second solenoid valve is opened and the first solenoid valve is closed, the second capillary tube remains in a conducting state, and the first capillary tube is in a closed state;

[0017] When 45℃<T 水 If it is detected that -12℃<T 环 ≤7℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 7℃<T 环 ≤25℃, the third capillary remains in the conductive state, the second solenoid valve is open and the first solenoid valve is closed, the second capillary remains in the conductive state, and the first capillary is in the closed state; if it is detected that 25℃≤T 环 , the first solenoid valve and the second solenoid valve are both open, at this time the first capillary, the second capillary and the third capillary are all in a conducting state;

[0018] in:

[0019] T 环 : ambient temperature; T 水 : The water temperature during circulation heating of the heat pump water heater or the water tank temperature during static heating.

[0020] After the fixed speed compressor runs for 5 minutes,

[0021] When the water temperature T 水 ≤35℃, if -12℃<T 环 ≤7℃, or 15℃<T 环 , the second capillary and the third capillary are in the on state, and the first capillary is in the off state; if 7℃<T 环 ≤15℃, the third capillary is in the on state, and the first and second capillaries are in the off state;

[0022] When 35℃<T 水 ≤45℃, if -12℃<T 环 ≤15℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 15℃<T 环 , the third capillary tube remains in a conducting state, the second solenoid valve is opened and the first solenoid valve is closed, the second capillary tube remains in a conducting state, and the first capillary tube is in a closed state;

[0023] When 45℃<T 水 If it is detected that -12℃<T 环 ≤7℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 7℃<T 环≤25℃, the third capillary remains in the conductive state, the second solenoid valve is open and the first solenoid valve is closed, the second capillary remains in the conductive state, and the first capillary is in the closed state; if it is detected that 25℃≤T 环 , the first solenoid valve and the second solenoid valve are both open, and at this time the first capillary, the second capillary, and the third capillary are all in a conducting state.

[0024] When the heat pump water heater is in the defrosting state, the first capillary tube, the second capillary tube, and the third capillary tube are all in the conducting state, and return to the flow state before defrosting 30 seconds after the defrosting ends;

[0025] In standby or shutdown state, the first capillary and the second capillary are both in a closed state, and the third capillary is in a conducting state;

[0026] When the heat pump water heater enters the refrigerant recovery mode, the first capillary tube, the second capillary tube and the third capillary tube are all in the conducting state until the heat pump water heater is shut down.

[0027] When the temperature value sensed by the return air temperature sensor T 回 The temperature value T sensed by the pipe temperature sensor 管 When the difference is less than or equal to 0, T 回 -T 管 ≤0, regardless of the ambient temperature and water temperature, the third capillary is in the on state, and the first and second capillaries are in the off state;

[0028] When the difference between the temperature value sensed by the return air temperature sensor and the temperature value sensed by the pipe temperature sensor is greater than 0, T 回 -T 管 >0, the states of the first capillary tube, the second capillary tube, and the third capillary tube are controlled according to the control method when the heat pump water heater is in the initial state.

[0029] The present invention controls the refrigerant flow rate according to different ambient temperatures and different water temperature states, and automatically distributes different refrigerant flow rates under different working conditions through control, thereby achieving stable operation, energy saving and high efficiency of the entire heat pump system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Attachment Figure 1 This is a structural diagram of the throttling device of the present invention;

[0031] Attachment Figure 2 Schematic diagram of the connection principle of the present invention. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0033] In the description of the present invention, it should be understood that if 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 are used to indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, they are only for the convenience of describing the present invention 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 cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0034] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, removable connections, or integral connections. They may refer to mechanical connections or electrical connections. They may refer to direct connections or indirect connections through an intermediary, and they may refer to internal communication between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0035] The present invention provides a throttling device on one hand, and a control method for the throttling device on the other hand, which will be described below according to different embodiments.

[0036] Example 1

[0037] As attached Figure 1 and 2As shown, a throttling device for a heat pump water heater includes a controller, a throttling assembly, a water temperature sensor, an ambient temperature sensor, a pipe temperature sensor, and a return air temperature sensor. The throttling assembly, the water temperature sensor, the ambient temperature sensor, the pipe temperature sensor, and the return air temperature sensor are respectively connected to the controller, and the controller controls the on and off of the throttling assembly. The water temperature sensor is generally installed on the water tank of the heat pump water heater, or on the circulation pipeline, and is used to detect the water temperature in the water tank during static heating of the heat pump water heater, or the temperature of the circulating hot water during the circulating hot water production state. The pipe temperature sensor is installed on the heat exchange coil of the heat pump water heater, and is used to detect the surface temperature of the heat exchange coil tube. The return air temperature sensor is usually installed at the return air port of the compressor of the heat pump water heater, and is used to detect the return air temperature. The ambient temperature sensor is used to detect the ambient temperature.

[0038] The throttling assembly includes a first capillary tube, a second capillary tube, and a third capillary tube. One end of the first capillary tube, the second capillary tube, and the third capillary tube are connected to a first flow divider, and the other ends of the first capillary tube, the second capillary tube, and the third capillary tube are connected to a second flow divider. The first capillary tube is provided with a first solenoid valve, and the second capillary tube is provided with a second solenoid valve. Both the first and second solenoid valves are connected to a controller. The third capillary tube is in a normally open state, that is, it is not provided with a corresponding valve and is in a straight-through state. The first and second capillaries are controlled by the opening / closing of the first and second solenoid valves to achieve the first and second capillary closed states.

[0039] Example 2

[0040] Based on Example 1, the throttling assembly is further described. The first flow divider is connected to a first filter, and the second flow divider is connected to a second filter, filtering the medium flowing through it. This entire throttling device is used in a heat pump water heater and is typically connected to a heat exchanger. The first flow divider divides the flowing medium into the first, second, and third capillary tubes, which then circulate through the three capillary tubes before being collected by the second flow divider. By controlling the different on / off states of the three capillaries, the corresponding refrigerant flow rate is controlled.

[0041] The first capillary, the second capillary and the third capillary are arranged in parallel, and the third capillary is arranged in the middle area between the first capillary and the second capillary.

[0042] Furthermore, the first, second, and third capillary tubes have the same inner diameter and length, enabling better flow control. The inner diameter and length of a single capillary tube set are based on an ambient dry-bulb temperature of 20°C, a wet-bulb temperature of 15°C, and a compressor discharge temperature no higher than 80°C and no lower than 70°C when the water temperature is heated to 55°C.

[0043] By utilizing the on-off control of the three capillaries, the refrigerant circulation volume during system operation can be adjusted according to changes in water temperature and ambient temperature.

[0044] Example 3

[0045] A method for controlling a throttling device of a heat pump water heater comprises the following steps:

[0046] The throttling device is applied to the heat pump water heater, which includes a constant-speed compressor, a heat exchange coil, and a water tank. The return air temperature sensor is arranged at the return air port of the constant-speed compressor, the pipe temperature sensor is arranged on the heat exchanger coil, the ambient temperature sensor is arranged around the heat exchanger coil, and the water temperature sensor is arranged on the water tank.

[0047] The heat pump water heater has an initial state, a defrost state, a hot water state, a standby state or an off state. The controller controls the opening or closing of the first solenoid valve and the second solenoid valve according to the current state of the heat pump water heater, and adjusts the conduction or closing state of the first capillary tube and the second capillary tube. The third capillary tube is always in a conducting state.

[0048] As a component in the heat pump water heater, the throttling device plays a corresponding throttling role in the entire system and regulates the refrigerant flow.

[0049] When the current operating mode is changed from shutdown or standby to hot water production, the fixed-speed compressor is considered to be in the initial state when it runs stably for 30 seconds after starting, and before the fixed-speed compressor runs for less than 5 minutes, this state is also a variable operating condition state, that is, the operating condition of the heat pump water heater is changing.

[0050] Detect the water temperature T 水 ≤35℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state;

[0051] When 35℃<T 水 ≤45℃, if -12℃<T 环 ≤15℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 15℃<T 环 , the third capillary tube remains in a conducting state, the second solenoid valve is opened and the first solenoid valve is closed, the second capillary tube remains in a conducting state, and the first capillary tube is in a closed state;

[0052] When 45℃<T 水 If it is detected that -12℃<T 环 ≤7℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 7℃<T环 ≤25℃, the third capillary remains in the conductive state, the second solenoid valve is open and the first solenoid valve is closed, the second capillary remains in the conductive state, and the first capillary is in the closed state; if it is detected that 25℃≤T 环 , the first solenoid valve and the second solenoid valve are both open, at this time the first capillary, the second capillary and the third capillary are all in a conducting state;

[0053] in:

[0054] T 环 : ambient temperature; T 水 : The water temperature during circulation heating of the heat pump water heater or the water tank temperature during static heating.

[0055] It can be simplified as shown in Table 1 below:

[0056]

[0057] After the fixed speed compressor runs for 5 minutes,

[0058] When the water temperature T 水 ≤35℃, if -12℃<T 环 ≤7℃, or 15℃<T 环 , the second capillary and the third capillary are in the on state, and the first capillary is in the off state; if 7℃<T 环 ≤15℃, the third capillary is in the on state, and the first and second capillaries are in the off state;

[0059] When 35℃<T 水 ≤45℃, if -12℃<T 环 ≤15℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 15℃<T 环 , the third capillary tube remains in a conducting state, the second solenoid valve is opened and the first solenoid valve is closed, the second capillary tube remains in a conducting state, and the first capillary tube is in a closed state.

[0060] When 45℃<T 水 If it is detected that -12℃<T 环 ≤7℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 7℃<T 环 ≤25℃, the third capillary remains in the conductive state, the second solenoid valve is open and the first solenoid valve is closed, the second capillary remains in the conductive state, and the first capillary is in the closed state; if it is detected that 25℃≤T 环, the first solenoid valve and the second solenoid valve are both open, and at this time the first capillary, the second capillary, and the third capillary are all in a conducting state.

[0061] This can be simplified as shown in Table 2 below:

[0062]

[0063] From Table 1 and Table 2 above, it can be seen that under variable operating conditions, the specific flow control between the three capillaries can achieve the control of the corresponding refrigerant flow rate.

[0064] When the heat pump water heater is in the defrosting state, the first capillary tube, the second capillary tube and the third capillary tube are all in the conducting state, and return to the flow state before defrosting 30 seconds after the defrosting ends.

[0065] In the standby or shutdown state, the first capillary and the second capillary are both in the closed state, and the third capillary is in the conducting state.

[0066] When the heat pump water heater enters the refrigerant recovery mode, the first capillary tube, the second capillary tube and the third capillary tube are all in the conducting state until the heat pump water heater is shut down.

[0067] When the temperature value sensed by the return air temperature sensor T 回 The temperature value T sensed by the pipe temperature sensor 管 When the difference is less than or equal to 0, T 回 -T 管 ≤0, regardless of the ambient temperature and water temperature, the third capillary is in the on state, and the first and second capillaries are in the off state;

[0068] When the difference between the temperature value sensed by the return air temperature sensor and the temperature value sensed by the pipe temperature sensor is greater than 0, T 回 -T 管 >0, the states of the first capillary tube, the second capillary tube, and the third capillary tube are controlled according to the control method when the heat pump water heater is in the initial state, that is, they are controlled according to the control method in Table 1.

[0069] In the present invention, the throttling device is set as a combination of three capillaries, in which the third capillary tube is always kept in a conductive state, so that there is always a path for circulating refrigerant, and then the combined on-off control of the first capillary tube and the second capillary tube is used to achieve the size control of the refrigerant flow.

[0070] It should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A control method for a throttling device of a heat pump water heater, the throttling device comprising a controller, a throttling assembly, a water temperature sensor, an ambient temperature sensor, a pipe temperature sensor, and a return air temperature sensor, wherein the throttling assembly, the water temperature sensor, the ambient temperature sensor, the pipe temperature sensor, and the return air temperature sensor are respectively connected to the controller, and the controller controls the on / off of the throttling assembly, the throttling assembly comprising a first capillary tube, a second capillary tube, and a third capillary tube, one end of the first capillary tube, the second capillary tube, and the third capillary tube is connected to a first diverter, and the other end of the first capillary tube, the second capillary tube, and the third capillary tube is connected to a second diverter, a first solenoid valve is provided on the first capillary tube, a second solenoid valve is provided on the second capillary tube, the first solenoid valve and the second solenoid valve are both connected to the controller, the third capillary tube is in a normally open conduction state, and the on / off of the first capillary tube and the second capillary tube is controlled by the on / off of the first solenoid valve and the second solenoid valve, the first diverter is connected to a first filter, and the second diverter is connected to a second filter, characterized in that The following steps are involved: The throttling device is applied to the heat pump water heater, which includes a fixed-speed compressor, a heat exchange coil, and a water tank. The return air temperature sensor is installed at the return air port of the fixed-speed compressor, the pipe temperature sensor is installed on the heat exchange coil, the ambient temperature sensor is installed around the heat exchange coil, and the water temperature sensor is installed on the water tank. The heat pump water heater has an initial state, a defrost state, a hot water state, a standby state, or a shutdown state. The controller controls the opening or closing of the first solenoid valve and the second solenoid valve according to the current state of the heat pump water heater, and adjusts the conduction or closing state of the first capillary tube and the second capillary tube. The third capillary tube is always in the conduction state. When the current operating mode changes from shutdown or standby to hot water state, the initial state is considered when the fixed-speed compressor starts and runs stably for 30 seconds, and before the fixed-speed compressor has been running for less than 5 minutes; Detect the water temperature T 水 ≤35℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; When 35℃<T 水 ≤45℃, if -12℃<T 环 ≤15℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 15℃<T 环 , the third capillary tube remains in a conducting state, the second solenoid valve is opened and the first solenoid valve is closed, the second capillary tube remains in a conducting state, and the first capillary tube is in a closed state; When 45℃<T 水 If it is detected that -12℃<T 环 ≤7℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 7℃<T 环 ≤25℃, the third capillary remains in the conductive state, the second solenoid valve is open and the first solenoid valve is closed, the second capillary remains in the conductive state, and the first capillary is in the closed state; if it is detected that 25℃≤T 环 , the first solenoid valve and the second solenoid valve are both open, at this time the first capillary, the second capillary and the third capillary are all in a conducting state; in: T 环 : ambient temperature; T 水 : The water temperature of the heat pump water heater during circulation heating or the water tank temperature during static heating; after the fixed speed compressor runs for 5 minutes, When the water temperature T 水 ≤35℃, if -12℃<T 环 ≤7℃, or 15℃<T 环 , the second capillary and the third capillary are in the on state, and the first capillary is in the off state; if 7℃<T 环 ≤15℃, the third capillary is in the on state, and the first and second capillaries are in the off state; When 35℃<T 水 ≤45℃, if -12℃<T 环 ≤15℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 15℃<T 环 , the third capillary tube remains in a conducting state, the second solenoid valve is opened and the first solenoid valve is closed, the second capillary tube remains in a conducting state, and the first capillary tube is in a closed state; When 45℃<T 水 If it is detected that -12℃<T 环 ≤7℃, the third capillary remains in the conductive state, the first solenoid valve and the second solenoid valve are closed, and the first capillary and the second capillary are in the closed state; if it is detected that 7℃<T 环 ≤25℃, the third capillary remains in the conductive state, the second solenoid valve is open and the first solenoid valve is closed, the second capillary remains in the conductive state, and the first capillary is in the closed state; if it is detected that 25℃≤T 环 , the first solenoid valve and the second solenoid valve are both open, and at this time the first capillary, the second capillary, and the third capillary are all in a conducting state.

2. The control method for a throttling device of a heat pump water heater according to claim 1, characterized in that: When the heat pump water heater is in the defrosting state, the first capillary tube, the second capillary tube, and the third capillary tube are all in the conducting state, and return to the flow state before defrosting 30 seconds after the defrosting ends; In standby or shutdown state, the first capillary and the second capillary are both in a closed state, and the third capillary is in a conducting state; When the heat pump water heater enters the refrigerant recovery mode, the first capillary tube, the second capillary tube and the third capillary tube are all in the conducting state until the heat pump water heater is shut down.

3. The control method for a throttling device of a heat pump water heater according to claim 2, characterized in that: When the temperature value sensed by the return air temperature sensor is T 回 The temperature value T sensed by the pipe temperature sensor 管 When the difference is less than or equal to 0, T 回 -T 管 ≤0, regardless of the ambient temperature and water temperature, the third capillary is in the on state, and the first and second capillaries are in the off state; When the difference between the temperature value sensed by the return air temperature sensor and the temperature value sensed by the pipe temperature sensor is greater than 0, T 回 -T 管 >0, the states of the first capillary tube, the second capillary tube, and the third capillary tube are controlled according to the control method when the heat pump water heater is in the initial state.

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