Heat pump unit system

Abstract

The invention provides a heat pump unit system which comprises an economizer, the economizer is arranged between a condenser and an evaporator of the heat pump unit system, and a refrigerant from the condenser is introduced into a first inlet and a second inlet of the economizer through a first inlet path and a second inlet path respectively; the economizer guides a refrigerant entering from the first inlet to the evaporator through the first outlet and the first outlet, and guides a refrigerant entering from the second inlet to an air supply port of a compressor of the heat pump unit system through the second outlet and the second outlet; the economizer expansion valve is arranged on the second inlet path, so that a refrigerant entering the economizer through the second inlet path passes through the economizer expansion valve; the inlet end of the liquid spraying valve communicates with the second inlet path, the communicating position is located at the inlet end of the economizer expansion valve, and the outlet end of the liquid spraying valve communicates with the air supplementing opening. By opening the liquid spraying valve, the refrigerant directly flows to the compressor from the liquid spraying valve, and the middle air supply pressure and the exhaust temperature can be effectively controlled.

Description

Technical Field

[0001] This invention relates to the field of heat pump system technology, and in particular to a heat pump unit system. Background Technology

[0002] As a heat exchange system, a heat pump unit also has four essential components: a compressor, a condenser, an evaporator, and an expansion valve. It utilizes a refrigerant circulation path composed of these components to exchange heat with the external environment. In existing technologies, some heat pump units also include an economizer and an economizer expansion valve. The economizer is located between the condenser and the evaporator. During the refrigerant flow from the condenser to the evaporator, it splits into two paths: one flows directly through the economizer, and the other passes through the economizer expansion valve before flowing through the economizer itself. This reduces the economizer's temperature, allowing the two refrigerant paths with different temperatures to exchange heat within the economizer, increasing the cooling capacity of the refrigerant flowing to the evaporator. Simultaneously, the refrigerant that has passed through the economizer expansion valve flows out of the economizer and towards the compressor's injection port, providing intermediate injection pressure to the compressor while simultaneously lowering the compressor's discharge temperature.

[0003] However, when the outlet water temperature of the heat pump unit is high, the intermediate gas injection pressure of the compressor can easily reach a critical value, leading to shutdown. In this case, it is necessary to close the economizer expansion valve. However, when the outlet water temperature of the heat pump unit is high, the compressor discharge temperature is also very high. Closing the economizer expansion valve can easily cause the compressor discharge temperature to become too high, leading to shutdown. Summary of the Invention

[0004] One objective of this invention is to provide a heat pump unit system that can effectively control the intermediate gas injection pressure and exhaust temperature of the compressor under high-temperature water output conditions, thereby reducing the occurrence of shutdown failures.

[0005] Specifically, the present invention provides a heat pump unit system, comprising:

[0006] An economizer is installed between the condenser and evaporator of the heat pump unit system. The first inlet and the second inlet of the economizer introduce refrigerant through the first inlet and the second inlet respectively. The economizer guides the refrigerant entering from the first inlet to the evaporator through the first outlet and the first outlet, and guides the refrigerant entering from the second inlet to the gas supply port of the compressor of the heat pump unit system through the second outlet and the second outlet.

[0007] Economizer expansion valve, the economizer expansion valve is located in the second inlet, so that the refrigerant entering the economizer via the second inlet passes through the economizer expansion valve; and

[0008] The liquid injection valve has its inlet end connected to the second inlet and the connection position is located at the inlet end of the economizer expansion valve. The outlet end of the liquid injection valve is connected to the air supply port.

[0009] Optionally, the inlet of the second approach is connected to the first outlet, and the outlet of the second approach is connected to the second inlet.

[0010] Optionally, the heat pump unit system further includes: an exhaust temperature sensor for detecting the exhaust temperature of the compressor; and

[0011] The injection valve is configured to open when the detected value of the exhaust temperature sensor is greater than or equal to a first exhaust temperature threshold.

[0012] Optionally, the heat pump unit system further includes: an outlet water temperature sensor, which is used to detect the water temperature after heat exchange with the condenser; and

[0013] The economizer expansion valve is configured to adjust to a preset opening degree when the detection value of the exhaust temperature sensor is greater than or equal to the first exhaust temperature threshold and the detection value of the outlet water temperature sensor is greater than or equal to the first outlet water temperature threshold.

[0014] Optionally, after the economizer expansion valve is adjusted to a preset opening degree, the injection valve is configured to close when the exhaust temperature sensor detects a value less than a second exhaust temperature threshold; and

[0015] The economizer expansion valve is configured to restore its initial opening degree when the detected value of the exhaust temperature sensor is less than a second exhaust temperature threshold.

[0016] The second exhaust temperature is lower than the first exhaust temperature.

[0017] Optionally, the economizer expansion valve is configured to maintain its current opening degree when the detection value of the exhaust temperature sensor is greater than or equal to the first exhaust temperature threshold and the detection value of the outlet water temperature sensor is less than the second outlet water temperature threshold.

[0018] The second outlet water temperature is lower than the first outlet water temperature.

[0019] Optionally, while the economizer expansion valve remains at its current opening level, the injection valve is configured to close if the exhaust temperature sensor detects a value less than a third exhaust temperature threshold.

[0020] The third exhaust temperature is lower than the first exhaust temperature.

[0021] Optionally, the heat pump unit system further includes a pressure status feedback device, which is used to reflect the intermediate gas injection pressure of the compressor.

[0022] Optionally, the pressure status feedback device is an inlet temperature sensor, which is used to detect the refrigerant temperature at the second inlet of the economizer, so as to provide feedback on the intermediate gas injection pressure of the compressor via the refrigerant temperature; and

[0023] The economizer expansion valve is configured to gradually reduce its opening degree according to a preset cycle when the detection value of the inlet temperature sensor is greater than or equal to a first refrigerant temperature threshold and less than a second refrigerant temperature threshold.

[0024] Optionally, the economizer expansion valve is configured to adjust its opening degree to a preset minimum value when the detection value of the inlet temperature sensor is greater than or equal to the second refrigerant temperature threshold.

[0025] Optionally, the economizer expansion valve is configured to return to its initial opening position if the detected value of the inlet temperature sensor is less than a third refrigerant temperature threshold, wherein the third refrigerant temperature threshold is less than the first refrigerant temperature threshold.

[0026] Optionally, the pressure status feedback device is a pressure sensor, which is used to detect the intermediate gas supply pressure of the compressor.

[0027] The heat pump unit system of this invention incorporates a liquid injection valve. The inlet of the liquid injection valve is connected to a second inlet located at the inlet of the economizer expansion valve, and the outlet of the liquid injection valve is connected to the gas inlet. When the liquid injection valve is open, the refrigerant flowing to the second inlet of the economizer can flow directly to the gas inlet of the compressor via the liquid injection valve, bypassing the economizer and its expansion valve. Therefore, even if the opening degree of the economizer expansion valve is adjusted to a smaller extent, it will not affect the flow of most of the refrigerant from the liquid injection valve to the gas inlet. Furthermore, because the refrigerant flowing from the liquid injection valve to the compressor's gas inlet does not undergo the vaporization process of the economizer expansion valve, it is mostly liquid. This significantly reduces the intermediate gas injection pressure caused by gas. Additionally, when the refrigerant flows from the liquid injection valve to the compressor's gas inlet and is injected, the liquid refrigerant atomizes, rapidly absorbing heat and evaporating, effectively reducing the compressor's exhaust temperature. In other words, when the outlet water temperature of the heat pump unit is high, even if the opening degree of the economizer expansion valve is adjusted to a very small extent, the refrigerant can flow directly to the compressor's gas injection port through the liquid injection valve by opening the liquid injection valve, without passing through the economizer and the economizer expansion valve. This effectively controls the compressor's intermediate gas injection pressure and exhaust temperature, effectively preventing the compressor's intermediate gas injection pressure from exceeding the critical value and effectively reducing the compressor's exhaust temperature.

[0028] Furthermore, the heat pump unit system of the present invention, by setting an exhaust temperature sensor and an outlet water temperature sensor, configures the injection valve to open when the detection value of the exhaust temperature sensor is greater than or equal to a first exhaust temperature threshold, and configures the economizer expansion valve to adjust to a preset opening degree when the detection value of the exhaust temperature sensor is greater than or equal to the first exhaust temperature threshold and the detection value of the outlet water temperature sensor is greater than or equal to the first outlet water temperature threshold. On the basis of reducing the exhaust temperature of the compressor and avoiding the intermediate gas injection pressure of the compressor from reaching the critical value, the detection value of the outlet water temperature sensor is used to indirectly reflect the intermediate gas injection pressure of the compressor. Because there is still a certain time after the refrigerant flows out of the condenser to reach the gas injection port of the compressor, it can more timely determine whether the intermediate gas injection pressure of the compressor gas injection port will exceed the critical value. In other words, it gives the unit system a judgment margin, avoiding the reaction at the moment when the intermediate gas injection pressure has reached the critical value, thereby effectively ensuring the normal operation of the compressor.

[0029] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0030] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0031] Figure 1 This is a schematic diagram of a heat pump unit system according to an embodiment of the present invention;

[0032] Figure 2 This is a partial schematic diagram of a heat pump unit system according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic flowchart of a control method for a heat pump unit system according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic flowchart of another control method for a heat pump unit system according to an embodiment of the present invention. Detailed Implementation

[0035] Those skilled in the art should understand that the embodiments described below are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. These partial embodiments are intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative effort should still fall within the scope of protection of the present invention.

[0036] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can also refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] like Figure 1 and Figure 2 As shown, in one embodiment, the heat pump unit system includes a compressor 100, a condenser 200, an evaporator 300, a mainline expansion valve 400, and an economizer 500. The economizer 500 is disposed between the condenser 200 and the evaporator 300 of the heat pump unit system. A first inlet 501 and a second inlet 502 of the economizer 500 introduce refrigerant via a first inlet 11 and a second inlet 12, respectively. Furthermore, the economizer 500 directs the refrigerant entering through the first inlet 501 to the evaporator 300 via a first outlet 503 and a first outlet 21, and directs the refrigerant entering through the second inlet 502 to the gas filler port of the compressor 100 of the heat pump unit system via a second outlet 504 and a second outlet 22.

[0038] Continue to refer to Figure 1 and Figure 2 As shown, the heat pump unit system also includes an economizer expansion valve 600 and a liquid injection valve 700. The economizer expansion valve 600 is located in the second inlet 12 so that the refrigerant entering the economizer 500 via the second inlet 12 passes through the economizer expansion valve 600. The inlet end of the liquid injection valve 700 is connected to the second inlet 12, and the connection position is located at the inlet end of the economizer expansion valve 600. The outlet end of the liquid injection valve 700 is connected to the gas supply port.

[0039] Furthermore, the inlet of the second approach 12 is connected to the first outlet 21, and the outlet of the second approach 12 is connected to the second inlet 502.

[0040] Reference Figure 1 and Figure 2As shown, in the operation of the heat pump unit in this embodiment, the compressor 100 is used to pressurize the gaseous refrigerant to obtain a high-temperature, high-pressure gaseous refrigerant. The gaseous refrigerant pressurized by the compressor 100 flows to the condenser 200. The condenser 200 is a shell-and-tube heat exchanger, in which the refrigerant and water exchange heat to obtain hot water for user use. The temperature of the water flowing out of the shell-and-tube heat exchanger is called the outlet water temperature of the heat pump unit.

[0041] Furthermore, after the refrigerant flows out of the condenser 200, it flows along the first inlet 11 to the economizer 500, and then flows into the economizer 500 from the first inlet 501. Next, the refrigerant that entered the economizer 500 from the first inlet 501 flows out from the first outlet 503 of the economizer 500, and flows from the first outlet 21 to the main expansion valve 400. After being depressurized by the main expansion valve 400, it flows to the evaporator 300.

[0042] Because the inlet of the second inlet 12 is connected to the first outlet 21, some of the refrigerant flowing out of the first outlet 503 of the economizer 500 will enter the second inlet 12 and then flow through the economizer expansion valve 600. The refrigerant cooled by the economizer expansion valve 600 enters the economizer 500 through the second inlet 502, where it exchanges heat with the refrigerant entering from the first inlet 501. This lowers the temperature of the refrigerant entering from the first inlet 501, further reducing the temperature of the refrigerant flowing to the evaporator 300 and improving the heat exchange efficiency with the outside environment. Then, the refrigerant entering the economizer 500 through the second inlet 502 flows out of the economizer 500 through the second outlet 504 and flows through the second outlet 22 to the compressor 100's gas injection port. Ultimately, the refrigerant entering through the compressor 100's air inlet merges with the refrigerant from the evaporator 300. Because the refrigerant entering through the compressor 100's air inlet has medium pressure, it can increase the refrigerant pressure before compression to a certain extent, thereby improving the compressor 100's working efficiency. At the same time, the refrigerant entering through the compressor 100's air inlet is also at a relatively low temperature, which helps to reduce the compressor 100's exhaust temperature.

[0043] When the outlet water temperature of the heat pump unit is high, that is, the refrigerant temperature in the condenser 200 is high, the refrigerant temperature flowing from the condenser 200 to the economizer 500 is also high, which in turn makes the refrigerant temperature flowing from the economizer 500 to the compressor 100 also high. High temperature means high pressure, that is, the pressure of the refrigerant flowing from the economizer 500 to the compressor 100 is too high, which is easy to exceed the critical value of the intermediate gas injection pressure. Therefore, it is necessary to close the economizer expansion valve 600 slightly.

[0044] Continue to refer to Figure 1 and Figure 2As shown, because a liquid injection valve 700 is provided, the inlet end of the liquid injection valve 700 is connected to the second inlet 12, and the outlet end of the liquid injection valve 700 is connected to the gas supply port of the compressor 100. That is to say, if the liquid injection valve 700 is open, the refrigerant in the second inlet 12 can flow directly to the gas supply port of the compressor 100 without passing through the economizer 500 and the economizer expansion valve 600.

[0045] In this embodiment, by installing a liquid injection valve 700 in the heat pump unit system, the inlet end of the liquid injection valve 700 is connected to the second inlet 12, with the connection position located at the inlet end of the economizer expansion valve 600, and the outlet end of the liquid injection valve 700 is connected to the gas injection port. When the liquid injection valve 700 is open, the refrigerant flowing to the second inlet 502 of the economizer 500 can flow directly to the gas injection port of the compressor 100 via the liquid injection valve 700, without passing through the economizer 500 and the economizer expansion valve 600. Therefore, even if the opening degree of the economizer expansion valve 600 is adjusted to a smaller degree, it will not affect the flow of most of the refrigerant from the liquid injection valve 700 to the gas injection port. Moreover, since the refrigerant flowing from the injection valve 700 to the gas inlet of the compressor 100 does not undergo the vaporization process of the economizer expansion valve 600, it is mostly liquid. On the one hand, this greatly reduces the intermediate gas injection pressure brought by the gas. On the other hand, when the refrigerant flows from the injection valve 700 to the gas inlet of the compressor 100 and is injected into the gas inlet, the liquid refrigerant is atomized and quickly absorbs heat and evaporates, effectively reducing the exhaust temperature of the compressor 100.

[0046] In other words, even when the outlet water temperature of the heat pump unit is high, although the opening degree of the economizer expansion valve 600 is adjusted to a very small extent, the refrigerant can flow directly to the gas injection port of the compressor 100 through the liquid injection valve 700 by opening the liquid injection valve 700, without passing through the economizer 500 and the economizer expansion valve 600. This effectively controls the intermediate gas injection pressure and exhaust temperature of the compressor 100, effectively preventing the intermediate gas injection pressure of the compressor 100 from exceeding the critical value and effectively reducing the exhaust temperature of the compressor 100.

[0047] Furthermore, by connecting the inlet end of the second inlet 12 to the first outlet 21 and the outlet end of the second inlet 12 to the second inlet 502 of the compressor 100, the refrigerant flowing to the economizer expansion valve 600 is the refrigerant flowing out of the first outlet 503 of the economizer 500, which is the refrigerant that has exchanged heat with the refrigerant entering from the second inlet 502 of the economizer 500. This helps to further reduce the temperature of the refrigerant flowing to the compressor 100. When the liquid injection valve 700 is open, it more effectively avoids excessive refrigerant pressure flowing to the air supply port of the compressor 100, thus ensuring the control effect of the exhaust temperature of the compressor 100.

[0048] It should be noted that in some other embodiments, the inlet end of the second inlet can also be connected to the first inlet. That is, the refrigerant flowing out of the condenser is divided into two paths before entering the economizer. One path directly enters the economizer from the first inlet and flows out of the economizer from the first outlet, while the other path enters the economizer from the second inlet after passing through the economizer expansion valve and flows out of the economizer from the second outlet.

[0049] Reference Figure 1 As shown, specifically, the heat pump unit system may also include a four-way valve 800, which is used to change the flow direction of the entire refrigeration circuit. The four-way valve 800 itself and its function in the refrigeration circuit are existing technologies and will not be described in detail here.

[0050] like Figure 1 As shown, the heat pump unit system also includes an exhaust temperature sensor 30, which is used to detect the exhaust temperature of the compressor. The injection valve 700 is configured to open when the detection value of the exhaust temperature sensor 30 is greater than or equal to a first exhaust temperature threshold. Specifically, when the detection value of the exhaust temperature sensor 30 is greater than or equal to the first exhaust temperature threshold, it indicates that the exhaust temperature of the compressor 100 is high. Therefore, the injection valve 700 is opened, allowing most of the refrigerant to flow directly to the air inlet of the compressor 100 through the injection valve 700, thereby reducing the exhaust temperature of the compressor 100. The exhaust temperature sensor can directly detect the exhaust temperature of the compressor 100, making the control of the injection valve 700 more timely.

[0051] Although not shown in the figure, the heat pump unit system also includes an outlet water temperature sensor, which is used to detect the water temperature after heat exchange with the condenser. Furthermore, the economizer expansion valve 600 is configured to adjust to a preset opening level when the detection value of the exhaust temperature sensor 30 is greater than or equal to a first exhaust temperature threshold and the detection value of the outlet water temperature sensor is greater than or equal to a first outlet water temperature threshold.

[0052] Specifically, if the detection value of the exhaust temperature sensor 30 is greater than or equal to the first exhaust temperature threshold and the detection value of the outlet water temperature sensor is greater than or equal to the first outlet water temperature threshold, it indicates that the exhaust temperature of the compressor 100 is high and requires refrigerant from the air inlet for cooling. At the same time, it indicates that the current outlet water temperature of the heat pump unit system is very high. Therefore, it is determined that the intermediate air inlet pressure flowing to the air inlet is very close to the critical value. So, the economizer expansion valve 600 is adjusted to a smaller preset opening degree. For example, the preset opening degree can be a value between 15% and 20% of the maximum opening degree of the economizer expansion valve 600.

[0053] Since the liquid injection valve 700 is already open and the economizer expansion valve 600 is adjusted to a smaller preset opening degree, very little refrigerant flows to the economizer expansion valve 600, meaning very little refrigerant is vaporized. Most of the refrigerant flows directly to the compressor 100's gas inlet via the liquid injection valve 700. While ensuring that most of the refrigerant can flow to the compressor 100's gas inlet through the liquid injection valve 700 to reduce the compressor 100's exhaust temperature, it ensures that only a very small amount of refrigerant flows to the compressor's gas inlet after heat exchange through the economizer 500, effectively preventing the compressor 100's intermediate gas inlet pressure from reaching the critical value.

[0054] In addition, the outlet water temperature sensor detects the outlet water temperature to indirectly reflect the intermediate gas injection pressure of the compressor 100. Since there is still a certain amount of time after the refrigerant flows out of the condenser 200 and reaches the gas injection port of the compressor 100, it can more timely determine whether the intermediate gas injection pressure of the compressor 100 gas injection port will exceed the critical value. In other words, it gives the unit system a judgment margin, avoiding the reaction at the moment when the intermediate gas injection pressure has reached the critical value, thereby effectively ensuring the normal operation of the compressor 100.

[0055] Furthermore, after the economizer expansion valve 600 is adjusted to a preset opening degree, the injection valve 700 is configured to close when the detection value of the exhaust temperature sensor 30 is less than a second exhaust temperature threshold. The economizer expansion valve 600 is also configured to return to its initial opening degree when the detection value of the exhaust temperature sensor 30 is less than the second exhaust temperature threshold. Herein, the second exhaust temperature is less than the first exhaust temperature.

[0056] Specifically, after the economizer expansion valve 600 is adjusted to the preset opening degree, if the exhaust temperature of the compressor 100 drops to the second exhaust temperature, it indicates that the exhaust temperature is already low, and the outlet water temperature has returned to a low level. The intermediate gas injection pressure of the compressor 100 is also unlikely to reach the critical value. Therefore, the liquid injection valve 700 is closed and the economizer expansion valve 600 is restored to its initial opening degree, which is the opening degree set by the economizer expansion valve 600 when the heat pump unit system starts to work.

[0057] By configuring the injection valve 700 to close when the exhaust temperature sensor 30 detects a value less than the second exhaust temperature threshold, and configuring the economizer expansion valve 600 to return to its initial opening position when the exhaust temperature sensor 30 detects a value less than the second exhaust temperature threshold, the economizer 500 returns to its normal operating level when the exhaust temperature sensor 30 detects a value less than the second exhaust temperature threshold. This allows the heat pump unit system to exchange heat with the outside environment more effectively, and the fact that the exhaust temperature sensor 30 detects a value less than the second exhaust temperature threshold helps ensure that the heat pump unit system operates at a normal level for a longer period of time.

[0058] Furthermore, the economizer expansion valve 600 is configured to maintain its current opening degree when the detection value of the exhaust temperature sensor 30 is greater than or equal to a first exhaust temperature threshold and the detection value of the outlet water temperature sensor is less than a second outlet water temperature threshold. While the economizer expansion valve 600 maintains its current opening degree, the injection valve 700 is configured to close when the detection value of the exhaust temperature sensor 30 is less than a third exhaust temperature threshold. The third exhaust temperature is less than the first exhaust temperature.

[0059] In conjunction with the preceding text, specifically, the second outlet water temperature is lower than the first outlet water temperature, and the third exhaust temperature is lower than the first exhaust temperature but higher than the second exhaust temperature. When the exhaust temperature sensor 30's detection value is greater than or equal to the first exhaust temperature threshold and the outlet water temperature sensor's detection value is lower than the second outlet water temperature threshold, it indicates that the compressor 100's exhaust temperature is high, requiring refrigerant from the air inlet for cooling. It also indicates that the current outlet water temperature of the heat pump unit system is high. However, the intermediate air inlet pressure flowing to the air inlet is still some distance from the critical value, so the economizer expansion valve 600 can be kept at its current open position.

[0060] With the economizer expansion valve 600 maintaining its current opening position, if the discharge temperature of the compressor 100 drops below the third discharge temperature threshold, since the outlet water temperature was originally only relatively high, the drop in the discharge temperature of the compressor 100 to below the third discharge temperature threshold indicates that the outlet water temperature has returned to a lower level, and the intermediate gas injection pressure of the compressor 100 is not likely to reach the critical value, so the injection valve 700 is closed.

[0061] Reference Figures 1 to 3 As shown, a methodological flow is used to further supplement and explain the content above:

[0062] In the operation of heat pump unit systems, control methods generally include:

[0063] Step S301: Obtain the detection value of the exhaust temperature sensor. Specifically, obtain the exhaust temperature of the compressor 100.

[0064] Step S302: Determine whether the detection value of the exhaust temperature sensor is greater than or equal to the first exhaust temperature threshold. If yes, proceed to step S304; otherwise, proceed to step S303. When the detection value of the exhaust temperature sensor 30 is greater than or equal to the first exhaust temperature threshold, it indicates that the exhaust temperature of the compressor 100 is too high, and the exhaust temperature of the compressor 100 needs to be reduced.

[0065] Step S303: Keep the spray valve closed. That is, do not open the spray valve 700.

[0066] Step S304: Control the liquid injection valve to open. When the detection value of the exhaust temperature sensor 30 is greater than or equal to the first exhaust temperature threshold, the liquid injection valve 700 is opened, so that most of the refrigerant flows directly to the air inlet of the compressor 100 through the liquid injection valve 700, thereby reducing the exhaust temperature of the compressor 100.

[0067] Step S305: Obtain the detection value of the outlet water temperature sensor.

[0068] Step S306: If the value detected by the outlet water temperature sensor is greater than or equal to the first outlet water temperature threshold, the economizer expansion valve is adjusted to a preset opening degree. If the value detected by the outlet water temperature sensor is greater than or equal to the first outlet water temperature threshold, it indicates that the current outlet water temperature of the heat pump unit system is very high. Therefore, it is determined that the intermediate gas supply pressure flowing to the gas supply port is very close to the critical value. Thus, the economizer expansion valve 600 is adjusted to a smaller preset opening degree. For example, the preset opening degree can be a value between 15% and 20% of the maximum opening degree of the economizer expansion valve 600.

[0069] In step S307, if the detected value of the exhaust temperature sensor is less than the second exhaust temperature threshold, the injection valve is closed. After the economizer expansion valve 600 is adjusted to the preset opening degree, if the exhaust temperature of the compressor 100 drops to the second exhaust temperature, it indicates that the exhaust temperature is already low, and the outlet water temperature has returned to a low level. The intermediate gas injection pressure of the compressor 100 is also unlikely to reach the critical value. Therefore, the injection valve 700 is closed and the economizer expansion valve 600 is restored to its initial opening degree, which is the opening degree set when the heat pump unit system starts working.

[0070] Step S308: When the value detected by the outlet water temperature sensor is less than the second outlet water temperature threshold, the economizer expansion valve is controlled to maintain its current opening position. Specifically, if the second outlet water temperature is less than the first outlet water temperature, and the value detected by the outlet water temperature sensor is less than the second outlet water temperature threshold, it indicates that the exhaust temperature of the compressor 100 is relatively high, but lower than the first outlet water temperature. This means that the current outlet water temperature of the heat pump unit system is relatively high, but the intermediate gas injection pressure flowing to the gas injection port is still some distance from the critical value. Therefore, the economizer expansion valve 600 can be kept at its current opening position.

[0071] Step S309: If the detected value of the exhaust temperature sensor is less than the third exhaust temperature threshold, the injection valve is closed. The third exhaust temperature is less than the first exhaust temperature but greater than the second exhaust temperature. Since the outlet water temperature is only relatively high, the drop in the exhaust temperature of the compressor 100 to below the third exhaust temperature threshold indicates that the outlet water temperature has returned to a lower level. The intermediate gas injection pressure of the compressor 100 is also unlikely to reach the critical value. Therefore, the injection valve 700 is closed and the economizer expansion valve 600 is restored to its initial opening degree, which is the opening degree set when the heat pump unit system starts working.

[0072] Reference Figure 1 and Figure 2 As shown, the heat pump unit system also includes a pressure status feedback device, which is used to reflect the intermediate gas injection pressure of the compressor, thereby facilitating the adjustment of the economizer expansion valve 600 based on the feedback value of the pressure status feedback device.

[0073] Specifically, the pressure status feedback device is an inlet temperature sensor 40, which is used to detect the refrigerant temperature at the second inlet 502 of the economizer 500, and to provide feedback on the intermediate gas supply pressure of the compressor 100 via the refrigerant temperature. Furthermore, the economizer expansion valve 600 is configured to gradually reduce its opening degree according to a preset cycle when the detected value of the inlet temperature sensor 40 is greater than or equal to a first refrigerant temperature threshold and less than a second refrigerant temperature threshold.

[0074] Specifically, if the detected value of the inlet temperature sensor 40 is greater than or equal to the first refrigerant temperature threshold but less than the second refrigerant temperature threshold, it indicates that the refrigerant temperature and pressure at the second inlet 502 of the economizer expansion valve 600 are high. Further increases in temperature could cause the intermediate gas injection pressure of the compressor 100 to reach a critical value. Therefore, the opening degree is gradually reduced according to a preset cycle. Specifically, the opening degree of the economizer expansion valve 600 is reduced at preset intervals, for example, by 4% every 30 seconds, to prevent the refrigerant temperature from continuing to rise. This continues until the detected value of the inlet temperature sensor 40 is less than the first refrigerant temperature threshold or the economizer expansion valve 600 reaches its minimum opening degree.

[0075] Furthermore, the economizer expansion valve 600 is configured to adjust its opening degree to a preset minimum value when the detection value of the inlet temperature sensor 40 is greater than or equal to the second refrigerant temperature threshold. When the detection value of the inlet temperature sensor 40 is greater than or equal to the second refrigerant temperature threshold, it indicates that the refrigerant temperature at the second inlet 502 of the economizer expansion valve 600 is very high, and the intermediate gas injection pressure of the compressor 100 is about to reach a critical value. Therefore, the opening degree of the economizer expansion valve 600 is directly adjusted to the preset minimum value. The preset minimum value is set according to the type of economizer expansion valve 600; for example, the minimum opening degree of some expansion valves is 10% of the maximum opening degree.

[0076] During the adjustment of the economizer expansion valve 600 based on the detection value of the inlet temperature sensor 40, the economizer expansion valve 600 is configured to return to its initial opening position when the detection value of the inlet temperature sensor 40 is less than a third refrigerant temperature threshold, where the third refrigerant temperature threshold is less than a first refrigerant temperature threshold. Furthermore, the economizer expansion valve 600 is configured to return to its initial opening position after maintaining a preset minimum value for a set time.

[0077] In addition, the economizer expansion valve 600 is configured to prevent increased opening degree when the detection value of the inlet temperature sensor 40 is greater than or equal to the fourth refrigerant temperature threshold and less than the first refrigerant temperature threshold, wherein the fourth refrigerant temperature threshold is greater than the third refrigerant temperature threshold.

[0078] Reference Figure 4 As shown, a methodological flow is used to further supplement and explain the content above:

[0079] In the operation of heat pump unit systems, control methods generally include:

[0080] Step S401: Obtain the detection value of the imported temperature sensor.

[0081] Step S402: Determine whether the detection value of the inlet temperature sensor is greater than or equal to the fourth refrigerant temperature threshold. If yes, proceed to step S404; otherwise, proceed to step S403.

[0082] Step S403: No action is taken. This means the heat pump unit system is controlled to operate according to its current state.

[0083] Step S404: Control the expansion valve of the economizer according to the detection value of the inlet temperature sensor.

[0084] Specifically, this step includes:

[0085] If the detected value of the imported temperature sensor is greater than or equal to the fourth refrigerant temperature threshold but less than the first refrigerant temperature threshold, it is prohibited to increase the opening degree of the economizer expansion valve.

[0086] When the value detected by the inlet temperature sensor is greater than or equal to the first refrigerant temperature threshold and less than the second refrigerant temperature threshold, the economizer expansion valve is controlled to gradually reduce its opening degree according to a preset cycle. This continues until the value detected by the inlet temperature sensor is less than the first refrigerant temperature threshold or the economizer expansion valve reaches its minimum opening degree.

[0087] When the detected value of the imported temperature sensor is greater than or equal to the second refrigerant temperature threshold, the control economizer expansion valve adjusts its opening degree to the preset minimum value.

[0088] Step S405: Determine whether the exit conditions have been met. If yes, proceed to step S406; otherwise, maintain the current state. Specifically, the exit conditions include the inlet temperature sensor's detection value being less than the third refrigerant temperature threshold, or the economizer expansion valve maintaining the minimum preset value for more than a set time.

[0089] Step S406: Control the expansion valve of the economizer to return to its initial opening position.

[0090] It should be noted that during the adjustment of the economizer expansion valve 600 based on the detection value of the inlet temperature sensor 40, the economizer expansion valve 600 and the liquid injection valve 700 also operate according to the detection values ​​of the exhaust temperature sensor 30 and the outlet water temperature sensor, as described above. That is, even if the economizer expansion valve 600 is reduced to a small opening degree based on the detection value of the inlet temperature sensor 40, if the detection value of the exhaust temperature sensor 30 is greater than or equal to the first exhaust temperature, the liquid injection valve 700 is opened. When the liquid injection valve 700 is open, most of the refrigerant flows directly to the compressor 100's gas injection port through the liquid injection valve 700, thereby effectively controlling the compressor 100's intermediate gas injection pressure and exhaust temperature. This effectively prevents the compressor 100's intermediate gas injection pressure from exceeding the critical value and effectively reduces the compressor 100's exhaust temperature.

[0091] By setting the exhaust temperature sensor 30, the inlet temperature sensor 40, and the outlet water temperature sensor, the economizer expansion valve 600 and the injection valve 700 operate according to the detection values ​​of the exhaust temperature sensor 30, the inlet temperature sensor 40, and the outlet water temperature sensor. This allows for multi-level control of the intermediate gas injection pressure and exhaust temperature of the compressor 100, ensuring more precise control that the intermediate gas injection pressure of the compressor 100 does not exceed the critical value while also preventing the exhaust temperature of the compressor 100 from becoming too high.

[0092] Furthermore, the pressure status feedback device is a pressure sensor, which is used to detect the intermediate gas injection pressure of the compressor.

[0093] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus or device (such as a computer-based system, a processor-included system or other system that can fetch and execute instructions from, an instruction execution system, apparatus or device).

[0094] The flowchart provided in this embodiment is not intended to indicate that the operations of the method will be performed in any particular order, or that all operations of the method are included in every case. Furthermore, the method may include additional operations. Within the scope of the technical concept provided by the method in this embodiment, additional variations can be made to the above method.

[0095] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A heat pump unit system, comprising: An economizer is provided between the condenser and the evaporator of the heat pump unit system. The economizer introduces refrigerant through a first inlet and a second inlet, respectively, and guides the refrigerant entering through the first inlet to the evaporator through a first outlet and a first outlet, and guides the refrigerant entering through the second inlet to the gas supply port of the compressor of the heat pump unit system through a second outlet and a second outlet. An economizer expansion valve is provided in the second inlet so that refrigerant entering the economizer via the second inlet passes through the economizer expansion valve. and The liquid injection valve has its inlet end connected to the second inlet and the connection position is located at the inlet end of the economizer expansion valve, and its outlet end is connected to the air supply port.

2. The heat pump unit system according to claim 1, wherein, The inlet of the second approach is connected to the first outlet, and the outlet of the second approach is connected to the second inlet.

3. The heat pump unit system according to claim 1, wherein, The heat pump unit system further includes: an exhaust temperature sensor, which is used to detect the exhaust temperature of the compressor; and The injection valve is configured to open when the detected value of the exhaust temperature sensor is greater than or equal to a first exhaust temperature threshold.

4. The heat pump unit system according to claim 3, wherein, The heat pump unit system further includes: an outlet water temperature sensor, which is used to detect the water temperature after heat exchange with the condenser; and The economizer expansion valve is configured to adjust to a preset opening degree when the detection value of the exhaust temperature sensor is greater than or equal to the first exhaust temperature threshold and the detection value of the outlet water temperature sensor is greater than or equal to the first outlet water temperature threshold.

5. The heat pump unit system according to claim 4, wherein, After the economizer expansion valve is adjusted to a preset opening degree, the injection valve is configured to close if the exhaust temperature sensor reading is less than a second exhaust temperature threshold; and The economizer expansion valve is configured to restore its initial opening degree when the detected value of the exhaust temperature sensor is less than a second exhaust temperature threshold. The second exhaust temperature is lower than the first exhaust temperature.

6. The heat pump unit system according to claim 4, wherein, The economizer expansion valve is configured to maintain its current opening degree when the detected value of the exhaust temperature sensor is greater than or equal to the first exhaust temperature threshold and the detected value of the outlet water temperature sensor is less than the second outlet water temperature threshold. The second outlet water temperature is lower than the first outlet water temperature.

7. The heat pump unit system according to claim 6, wherein, With the economizer expansion valve maintaining its current opening position, the injection valve is configured to close if the exhaust temperature sensor reading is less than a third exhaust temperature threshold. The third exhaust temperature is lower than the first exhaust temperature.

8. The heat pump unit system according to claim 1, wherein, The heat pump unit system also includes a pressure status feedback device, which is used to reflect the intermediate gas injection pressure of the compressor.

9. The heat pump unit system according to claim 8, wherein, The pressure feedback device is an inlet temperature sensor, which detects the refrigerant temperature at the second inlet of the economizer, and uses this refrigerant temperature to provide feedback on the intermediate gas injection pressure of the compressor; and The economizer expansion valve is configured to gradually reduce its opening degree according to a preset cycle when the detection value of the inlet temperature sensor is greater than or equal to a first refrigerant temperature threshold and less than a second refrigerant temperature threshold.

10. The heat pump unit system according to claim 9, wherein, The economizer expansion valve is configured to adjust its opening degree to a preset minimum value when the detection value of the inlet temperature sensor is greater than or equal to the second refrigerant temperature threshold.

11. The heat pump unit system according to claim 10, wherein, The economizer expansion valve is configured to return to its initial opening position if the detected value of the inlet temperature sensor is less than a third refrigerant temperature threshold, wherein the third refrigerant temperature threshold is less than the first refrigerant temperature threshold.

12. The heat pump unit system according to claim 8, wherein, The pressure status feedback device is a pressure sensor, which is used to detect the intermediate gas supply pressure of the compressor.

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