Heating and ventilation system, control method and device thereof and storage medium

Abstract

The invention discloses a heating and ventilation system, a control method and device of the heating and ventilation system and a storage medium, and the method comprises the steps that the target supercooling degree of a condenser is determined according to the middle temperature of the condenser and the temperature of the environment where the condenser is located; according to the middle temperature and the outlet temperature of the condenser, the actual supercooling degree of the condenser is determined; and the refrigerant flow in the heating and ventilation system is adjusted, so that the difference value between the actual supercooling degree and the target supercooling degree is within a first preset range. Compared with the prior art, the refrigerant flow in the system is controlled according to the supercooling degree of the condenser, it is ensured that the effective refrigerant amount in the system is in the optimal state, and therefore the capacity attenuation proportion of the system during long pipe distribution can be greatly reduced.

Description

Technical Field

[0001] This application belongs to the technical field of heating, ventilation and air conditioning (HVAC), and particularly relates to an HVAC system, its control method, device, and storage medium. Background Art

[0002] In an HVAC system, a long refrigerant pipe refers to a situation where the length of the refrigerant pipe connecting the indoor unit and the outdoor unit exceeds the conventional design range. This is relatively common in some large buildings, special installation environments, or multi-split air conditioning systems. When the refrigerant pipe of the HVAC system is long, the volume of the pipeline increases. In the cooling and heating modes, due to different refrigerant phases and flow rate requirements. For example, during cooling, the pipe contains a gas-liquid two-phase state, and the volume ratio of the liquid phase is less than 1%, and the amount of refrigerant in the pipe is almost negligible; during heating, the pipe is filled with pure liquid, and the amount of refrigerant in the pipe is equal to the volume of the pipeline.

[0003] The impact of the long pipeline on the refrigerant amount is more significant. For example, during cooling, the liquid refrigerant flowing in the long liquid pipe will be affected by factors such as pipeline resistance, which will affect its flow rate and state; during heating, the long pipeline also affects the refrigerant circulation and distribution, and this impact is different in the two modes. The long refrigerant pipe further amplifies the difference in the refrigerant amount required in the cooling and heating modes, increasing the difficulty of precise control of the refrigerant amount by the system. If the refrigerant amount is added according to the cooling mode during installation, in the heating mode, due to the different refrigerant amounts required for heating and cooling, there may be a situation of insufficient refrigerant amount. This will lead to insufficient heat release in the indoor unit due to insufficient refrigerant amount, resulting in a significant decrease in heating capacity and difficulty in reaching the set indoor temperature. On the contrary, if the refrigerant amount is added according to the heating mode, there may be too much refrigerant during cooling. The excessive liquid refrigerant cannot be completely evaporated in the evaporator in time, resulting in a reduction in the effective heat exchange area of the evaporator, and the cooling capacity will also decrease significantly.

[0004] The mismatch of the refrigerant amount also has a serious impact on the reliability of the HVAC system. When there is too much refrigerant in the cooling mode, the liquid refrigerant may flow back to the compressor, causing a liquid slugging phenomenon. Liquid slugging will have a strong impact on components such as valve plates and pistons inside the compressor. Over time, these components will be damaged, reducing the service life of the compressor, and even causing the compressor to suddenly malfunction. In the heating mode, insufficient refrigerant amount will cause the suction pressure of the compressor to be too low, increasing the compression ratio. The compressor will be in a high-load operating state for a long time, which not only increases power consumption but also accelerates the wear of the compressor, and also affects the reliability and stability of the system.

[0005] In summary, during cooling and heating, the refrigerant phases in the pipe are different, and the refrigerant amounts in the pipeline are also different. When the pipeline is long, the difference in the refrigerant amount is amplified. Whether the refrigerant in the installed pipe is added according to cooling or heating, it will cause a serious mismatch in the refrigerant amount in the other operating mode, resulting in a significant attenuation of capacity or a decrease in reliability. Summary of the Invention

[0006] In view of this, embodiments of the present application provide a heating, ventilation and air conditioning (HVAC) system, and its control method, device, and storage medium to solve at least one of the above technical problems.

[0007] An embodiment of the first aspect of the present application provides an HVAC system, which includes a heat source side heat exchanger, a load side heat exchanger, a heat source side flow regulating valve, and a control module for controlling the HVAC system. The control module includes a control method, and the method includes:

[0008] Obtain the operating mode of the HVAC system, where the operating mode is one of a cooling mode and a heating mode;

[0009] According to the operating mode being the cooling mode, determine that the heat source side heat exchanger is a condenser, or according to the operating mode being the heating mode, confirm that the load side heat exchanger is a condenser;

[0010] Determine the target subcooling degree of the condenser according to the middle temperature of the condenser and the ambient temperature where it is located;

[0011] Determine the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser;

[0012] Adjust the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system, so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range.

[0013] For the HVAC system according to the embodiment of the first aspect of the present application, the target subcooling degree of the condenser is determined according to the middle temperature of the condenser and the ambient temperature where it is located; the actual subcooling degree of the condenser is determined according to the middle temperature and the outlet temperature of the condenser; the refrigerant flow rate in the HVAC system is adjusted so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range. Compared with the prior art, the present application controls the refrigerant flow rate in the system according to the subcooling degree of the condenser, ensuring that the effective refrigerant amount in the system is in the best state, thereby being able to significantly reduce the capacity attenuation ratio of the system during long refrigerant pipelines.

[0014] In a possible implementation, the determining the target subcooling degree of the condenser according to the middle temperature of the condenser and the ambient temperature where it is located includes:

[0015] Determine the product of the difference between the middle temperature of the condenser and the ambient temperature where it is located and a preset coefficient as the target subcooling degree of the condenser.

[0016] In a possible implementation, the value range of the preset coefficient is determined according to the environment where the condenser is located.

[0017] In a possible implementation, the environment where the condenser is located is outdoors, and the value range of the preset coefficient includes 0.3 to 0.6; when the environment where the condenser is located is indoors, the value range of the preset coefficient is 0.5 to 0.8.

[0018] In a possible implementation, before adjusting the refrigerant flow rate in the refrigerant circulation loop, the method further includes:

[0019] Correcting the target subcooling degree according to the exhaust temperature of the compressor.

[0020] In a possible implementation, the correcting the target subcooling degree according to the exhaust temperature of the compressor includes:

[0021] Keeping the current target subcooling degree unchanged according to the exhaust temperature being within the second preset range;

[0022] Increasing or decreasing the target subcooling degree according to the exhaust temperature being outside the second preset range until the exhaust temperature is within the second preset range.

[0023] In a possible implementation, the increasing or decreasing the target subcooling degree according to the exhaust temperature being outside the second preset range includes:

[0024] Reducing the target subcooling degree by a first preset step length according to the exhaust temperature being greater than or equal to the upper limit of the second preset range;

[0025] Increasing the target subcooling degree by a first preset step length according to the exhaust temperature being less than or equal to the lower limit of the second preset range.

[0026] In a possible implementation, the value range of the upper limit of the second preset range includes 95 to 105 degrees Celsius;

[0027] When the environment where the condenser is located is outdoors, the value range of the lower limit of the second preset range includes the outdoor temperature + 15 degrees Celsius to the outdoor temperature + 25 degrees Celsius;

[0028] When the environment where the condenser is located is indoors, the value range of the lower limit of the second preset range includes the indoor temperature + 25 degrees Celsius to the indoor temperature + 35 degrees Celsius.

[0029] In a possible implementation, the value range of the first preset step length includes 1 to 2 degrees Celsius.

[0030] In a possible implementation, adjusting the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range includes:

[0031] If the difference is within the first preset range, keep the current refrigerant flow rate unchanged;

[0032] If the difference is outside the first preset range, increase or decrease the refrigerant flow rate until the difference is within the first preset range.

[0033] In a possible implementation, the increasing or decreasing the refrigerant flow rate according to the difference being outside the first preset range includes:

[0034] If the difference is greater than or equal to the upper limit of the first preset range, increase the refrigerant flow rate in accordance with a second preset step size;

[0035] If the difference is less than or equal to the lower limit of the first preset range, decrease the refrigerant flow rate in accordance with a second preset step size.

[0036] In a possible implementation, the first preset range includes -1 to 1 degree Celsius.

[0037] For the heating and ventilation system according to the second aspect embodiment of the present application, the heating and ventilation system includes: a heat source side heat exchanger, a load side heat exchanger, a heat source side flow regulating valve, and a control module for controlling the heating and ventilation system. The control module includes a control device, and the device includes:

[0038] An acquisition module, configured to acquire the working mode of the heating and ventilation system, where the working mode is one of a cooling mode and a heating mode; according to the working mode being the cooling mode, determine that the heat source side heat exchanger is a condenser, or according to the working mode being the heating mode, confirm that the load side heat exchanger is a condenser;

[0039] A determination module, configured to determine the target subcooling degree of the condenser according to the middle temperature and the ambient temperature of the condenser; determine the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser;

[0040] An adjustment module, configured to adjust the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the heating and ventilation system, so that the difference between the actual subcooling degree and the target subcooling degree is within the first preset range.

[0041] In a possible implementation, the determination module is specifically configured to:

[0042] Determine the target subcooling degree of the condenser by multiplying the difference between the middle temperature of the condenser and the ambient temperature by a preset coefficient.

[0043] In a possible implementation, the value range of the preset coefficient is determined according to the environment where the condenser is located.

[0044] In a possible implementation, the condenser is a heat source side heat exchanger, and the value range of the preset coefficient includes 0.3 to 0.6; the condenser is a load side heat exchanger, and the value range of the preset coefficient is 0.5 to 0.8.

[0045] In a possible implementation, the determining module is further configured to: before adjusting the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system, correct the target subcooling degree according to the exhaust temperature of the compressor.

[0046] In a possible implementation, the determining module is specifically configured to:

[0047] Keep the current target subcooling degree unchanged according to the exhaust temperature being within the second preset range;

[0048] Increase or decrease the target subcooling degree according to the exhaust temperature being outside the second preset range until the exhaust temperature is within the second preset range.

[0049] In a possible implementation, the determining module is specifically configured to:

[0050] Decrease the target subcooling degree by a first preset step according to the exhaust temperature being greater than or equal to the upper limit of the second preset range;

[0051] Increase the target subcooling degree by a first preset step according to the exhaust temperature being less than or equal to the lower limit of the second preset range.

[0052] In a possible implementation, the value range of the upper limit of the second preset range includes 95 to 105 degrees Celsius;

[0053] When the environment where the condenser is located is outdoors, the value range of the lower limit of the second preset range includes the outdoor temperature + 15 degrees Celsius to the outdoor temperature + 25 degrees Celsius;

[0054] When the environment where the condenser is located is indoors, the value range of the lower limit of the second preset range includes the indoor temperature + 25 degrees Celsius to the indoor temperature + 35 degrees Celsius.

[0055] In a possible implementation, the value range of the first preset step includes 1 to 2 degrees Celsius.

[0056] In a possible implementation, the adjusting module is specifically configured to:

[0057] Keep the current refrigerant flow rate unchanged according to the difference being within the first preset range;

[0058] If the difference is outside the first preset range, increase or decrease the refrigerant flow rate until the difference is within the first preset range.

[0059] In a possible implementation, the adjustment module is specifically configured to:

[0060] If the difference is greater than or equal to the upper limit of the first preset range, increase the refrigerant flow rate according to a second preset step size;

[0061] If the difference is less than or equal to the lower limit of the first preset range, decrease the refrigerant flow rate according to a second preset step size.

[0062] In a possible implementation, the first preset range includes -1 to 1 degree Celsius.

[0063] The computer-readable storage medium according to the third aspect embodiment of the present application stores computer-readable instructions, and the computer-readable instructions can be executed by a processor to implement the control method of the first aspect embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0065] Figure 1 Shows the structural schematic diagram of the HVAC system in the refrigeration mode provided by the embodiment of the present application;

[0066] Figure 2 Shows the structural schematic diagram of the HVAC system in the heating mode provided by the embodiment of the present application;

[0067] Figure 3 Shown as Figure 1 、 2 The structural schematic diagram of the heat source side heat exchanger in

[0068] Figure 4 Shown as Figure 1 、 2 The structural schematic diagram of the load side heat exchanger in

[0069] Attached Figure 5 Shows the flowchart of a control method for an HVAC system provided by the present application;

[0070] Attached Figure 6A and 6B Shows the flowchart of correcting the target subcooling degree provided by the present application;

[0071] Appendix Figure 7A and 7B shows a flowchart for regulating the refrigerant flow rate in a heating, ventilation, and air conditioning (HVAC) system provided by the present application;

[0072] Appendix Figure 8 shows a schematic diagram of a control device for a heating, ventilation, and air conditioning (HVAC) system according to an embodiment of the present application.

[0073] The realization, functional features, and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0074] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0075] It should be noted that all directional indications (such as up, down, left, right, front, back,...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0076] In addition, the descriptions such as "first" and "second" in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0077] In the present invention, unless otherwise clearly defined and limited, the terms "connected" and "fixed" should be understood in a broad sense. For example, "fixed" may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0078] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0079] In order to make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe in detail the specific embodiments of the present application with reference to the accompanying drawings.

[0080] Figure 1 The following shows a schematic structural diagram of a heating and ventilation system in a refrigeration mode provided by an embodiment of the present application;

[0081] Figure 2 The following shows a schematic structural diagram of a heating and ventilation system in a heating mode provided by an embodiment of the present application;

[0082] Figure 3 The following shows Figure 1 、 2 a schematic structural diagram of a heat source side heat exchanger in

[0083] Figure 4 The following shows Figure 1 、 2 a schematic structural diagram of a load side heat exchanger in

[0084] Please refer to Figures 1-4 . This heating and ventilation system includes a heat source side unit, a load side unit, and a connecting pipe assembly connecting the heat source side unit and the load side unit. The heat source side unit, the load side unit, and the connecting pipe assembly connecting the two form a refrigerant circulation loop.

[0085] The heat source side unit includes a heat source housing, a compressor, a four-way valve, a gas side stop valve, a liquid side stop valve, a heat source side heat exchanger, a heat source side flow regulating valve, a plurality of temperature sensors, a plurality of filters, and a pipe assembly constituting the heat source side refrigerant circulation loop.

[0086] The heat source housing is configured as a hollow shell. The compressor, the four-way valve, the heat source side heat exchanger, the plurality of temperature sensors, the plurality of filters, the heat source side flow regulating valve, and the first pipe assembly are housed in the heat source housing. The gas stop valve and the liquid stop valve can be all housed in the heat source housing, or partially exposed outside the heat source housing.

[0087] The compressor is a machine that compresses low-pressure refrigerant into high-pressure refrigerant. In the refrigerant circulation loop, the suction port of the compressor recovers the low-pressure refrigerant, and after compression, discharges the high-temperature and high-pressure refrigerant. The compressor in the present application can be a rotary compressor or a scroll compressor, which is not limited herein.

[0088] The heat source side heat exchanger exchanges heat with an external heat source. The heat source of the heat source side heat exchanger can be air, water source, ground source, etc. As Figure 3As shown, the heat source side heat exchanger has a gas side communication part and a liquid side communication part. On the refrigerant circulation path, the gas side communication part is closer to the compressor than the liquid side communication part. The liquid side communication part leads to the load side unit. There is a liquid side stop valve between the liquid side communication part and the load side communication part. This liquid side stop valve has two states: closed and open, so as to control the on-off between the liquid side communication part and the load side unit, that is, to control the on-off of the liquid side flow path between the heat source side unit and the load side unit.

[0089] The four-way valve has four interfaces, which are respectively defined as the first interface, the second interface, the third interface and the fourth interface. The first interface is connected to the exhaust port of the compressor, the second interface is connected to the gas side communication part of the heat source side heat exchanger, the third interface is connected to the suction port of the compressor, and the fourth interface is connected to the load side unit. There is a gas side stop valve between the fourth interface and the load side unit. This gas side stop valve has two states: closed and open, so as to control the on-off between the fourth interface and the load side unit, that is, to control the on-off of the gas side flow path between the heat source side unit and the load side unit.

[0090] The four-way valve further has a switching switch. By moving the switching switch, the first interface can be selectively connected to the second interface or the fourth interface. When the first interface is connected to the second interface, the third interface is connected to the fourth interface. At this time, the refrigerant circulation circuit is in the cooling mode; when the first interface is connected to the fourth interface, the second interface is connected to the third interface. At this time, the refrigerant circulation circuit is in the heating mode. Therefore, the four-way valve is also called a cooling and heating switching valve.

[0091] The multiple temperature sensors arranged in the heat source side unit include a first temperature sensor T1, a second temperature sensor T2, and a third temperature sensor T3. The first temperature sensor T1 detects the ambient temperature of the environment where the heat source side unit is located, the second temperature sensor T2 detects the middle temperature of the heat source side heat exchanger, and the third temperature sensor T3 detects the temperature of the liquid side of the heat source side heat exchanger. When the refrigerant circulation circuit is in the cooling mode, the heat source side heat exchanger acts as a condenser, and the temperature of its liquid side is the outlet temperature of the condenser.

[0092] The first temperature sensor T1 is installed near the heat source side heat exchanger. Taking the heat source heat exchanger as an air heat source heat exchanger as one embodiment, there is a fan in the heat source side unit. The fan drives the outside air through the heat source side heat exchanger, so that the outside air exchanges heat with the heat source heat exchanger. The air after heat exchange is discharged to the outside through the exhaust port of the heat source housing. The first temperature sensor T1 is arranged on the windward side of the heat source side heat exchanger. When the fan drives the outside air through the heat exchanger, the first temperature sensor T1 detects the temperature of the outside air to obtain the ambient temperature of the heat source side unit. Taking the heat source heat exchanger as a water source heat exchanger as another embodiment, the first temperature sensor T1 is arranged at the water inlet of the outside water source of the water source heat exchanger.

[0093] The second temperature sensor T2 and the third temperature sensor T3 are arranged in the heat exchange tubes of the heat source side heat exchanger. More specifically, a plurality of branch heat exchange tubes are formed between the gas side communication part and the liquid side communication part of the heat source side heat exchanger. The refrigerant flowing in the branch heat exchange tubes exchanges heat with the external heat source. Each of the heat exchange branch tubes extends meanderingly along the height direction of the heat source side heat exchanger, forming a plurality of bending parts. Both sides of each branch heat exchange tube are exposed outside the heat source heat exchanger and are respectively communicated with the gas side communication part and the liquid side communication part. Along the refrigerant circulation path, they are arranged in sequence among the plurality of bending parts. The second temperature sensor T2 is arranged at one of the bending parts closest to the liquid side communication part in one of the branch heat exchange tubes. The third temperature sensor T3 is arranged at the end side of the branch heat exchange tube, and this end side is communicated with the liquid side communication part. When the refrigerant circulation loop is in the refrigeration mode, the heat source side heat exchanger serves as a condenser, and this end side of the branch heat exchange tube is the outlet temperature of the condenser.

[0094] A heat source side flow regulating valve is arranged between the liquid side communication part of the heat source side heat exchanger and the liquid side stop valve. The flow regulating valve in this application can be an electronic expansion valve. By adjusting the opening degree of the heat source side regulating valve, the refrigerant flow rate in the refrigerant circulation loop is controlled. A filter is arranged on each side of the heat source side flow regulating valve, or a filter is arranged between the electronic expansion valve and the liquid side stop valve.

[0095] The load side unit is arranged in the target space to be temperature-controlled. The load side unit has a load housing, and the load housing is provided with an air inlet and an air outlet. Both the air inlet and the air outlet are in air communication with the target space. Inside the load housing, a load side heat exchanger and a fan are accommodated. The load side heat exchanger is arranged between the air inlet and the air outlet. The fan drives the air in the target space to enter the load housing from the air inlet. After heat exchange through the load heat exchanger, it returns to the target space through the air outlet. The load side heat exchanger exchanges heat with the air in the target air conditioner, thereby adjusting the ambient temperature of the target space.

[0096] Such as Figure 4As shown, the load-side heat exchanger has a gas-side connection part and a liquid-side connection part. The gas-side connection part is correspondingly connected to the gas-side stop valve of the heat source-side unit, and the liquid-side connection is correspondingly connected to the liquid-side stop valve. A load-side flow regulating valve is provided on the liquid-side connection part. The load-side flow regulating valve in this application can be an electronic expansion valve.

[0097] The load-side unit further includes a plurality of temperature sensors. The plurality of temperature sensors include a fourth temperature sensor T4, a fifth temperature sensor T5, and a sixth temperature sensor T6. The fourth temperature sensor T4 detects the ambient temperature of the environment where the load-side unit is located, that is, the ambient temperature of the target space. The fifth temperature sensor T5 detects the middle temperature of the load-side heat exchanger. The sixth temperature sensor T6 detects the temperature of the liquid side of the load-side heat exchanger. When the refrigerant circulation circuit is in the heating mode, the load-side heat exchanger serves as a condenser, and the temperature of its liquid side is the outlet temperature of the condenser.

[0098] In one embodiment, the fourth temperature sensor T4 is provided at the air inlet, or, in another embodiment, the fourth temperature sensor T4 is provided in the electric control box of the load-side unit.

[0099] The fifth temperature sensor T5 and the sixth temperature sensor T6 are provided in the heat exchange tubes of the load-side heat exchanger. More specifically, a plurality of branch heat exchange tubes are formed between the gas-side connection part and the liquid-side connection part of the load-side heat exchanger. The refrigerant flowing in the branch heat exchange tubes exchanges heat with the external heat source. Each of the heat exchange branch tubes extends meanderingly along the height direction of the load-side heat exchanger, forming a plurality of bending parts. Both sides of each branch heat exchange tube are exposed outside the load-side heat exchanger and are respectively connected to the gas-side connection part and the liquid-side connection part. Along the refrigerant circulation path, the plurality of bending parts are arranged in sequence. The fifth temperature sensor T5 is provided in one of the bending parts closest to the liquid-side connection part in one of the branch heat exchange tubes. The sixth temperature sensor T6 is provided at the end side of the branch heat exchange tube, and this end side is connected to the liquid-side connection part. When the refrigerant circulation circuit is in the heating mode, the load-side heat exchanger serves as a condenser, and this end side of the branch heat exchange tube is the outlet temperature of the condenser.

[0100] The refrigerant circulation circuit has two working modes, a refrigeration mode and a heating mode. The refrigerant circulation flow paths of these two modes are described below.

[0101] Refrigeration mode:

[0102] As Figure 1As shown in the figure, in the refrigeration mode, the heat source side heat exchanger is a condenser, and the load side heat exchanger is an evaporator. In the refrigeration mode, the refrigerant enters the compressor in the form of a low-temperature and low-pressure gas. The compressor compresses the refrigerant, turning it into a high-temperature and high-pressure gaseous refrigerant. After the high-temperature and high-pressure gaseous refrigerant is discharged from the compressor, it enters the heat source side heat exchanger. In the heat source side heat exchanger, the refrigerant exchanges heat with the external environment. Through heat dissipation, the gaseous refrigerant gradually cools and condenses into a high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant passes through the expansion valve, causing the pressure of the refrigerant to drop sharply, thereby turning the refrigerant into a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant enters the load side heat exchanger. In the load side heat exchanger, the refrigerant absorbs heat and quickly evaporates into a low-temperature and low-pressure gaseous refrigerant, thus achieving the refrigeration effect. The evaporated gaseous refrigerant returns to the compressor again to start a new cycle.

[0103] Heating mode:

[0104] As Figure 2 shown in the figure, in the heating mode, the heat source side heat exchanger is an evaporator, and the load side heat exchanger is a condenser. In the heating mode, the refrigerant is sucked into the compressor in the form of a low-temperature and low-pressure gas. After being compressed by the compressor, it becomes a high-temperature and high-pressure gaseous refrigerant. The high-temperature and high-pressure gaseous refrigerant coming out of the compressor enters the four-way valve. The four-way valve changes the flow direction of the refrigerant in the heating mode, causing the refrigerant to flow to the load side heat exchanger. The high-temperature and high-pressure gaseous refrigerant enters the load side heat exchanger. In the load side heat exchanger, the refrigerant exchanges heat and releases heat, raising the surrounding temperature. The gaseous refrigerant gradually cools and condenses into a high-temperature and high-pressure liquid refrigerant during the heat release process. After the high-temperature and high-pressure liquid refrigerant flows out of the load side heat exchanger, it passes through the expansion valve, causing the pressure of the refrigerant to drop sharply and becoming a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant enters the heat source side heat exchanger. In the heat source side heat exchanger, the refrigerant absorbs heat from the environment and evaporates into a low-temperature and low-pressure gaseous refrigerant. During this process, the surface temperature of the heat source side heat exchanger decreases and may frost. The low-temperature and low-pressure gaseous refrigerant coming out of the heat source side heat exchanger enters the four-way valve again and returns to the compressor through the guidance of the four-way valve to start a new cycle.

[0105] As Figure 1 、 2 shown in the figure, the refrigerant circulation loop between the heat source side heat exchanger and the load side heat exchanger is connected through a long refrigerant pipe. The size of the refrigerant flow in the long refrigerant pipe is controlled by the opening degree of the heat source side flow regulating valve.

[0106] Embodiment 1

[0107] Figure 5 is a flowchart of a control method for a heating and ventilation system provided by an embodiment of the present application. As Figure 5 shown in the figure, the control method of the heating and ventilation system includes:

[0108] Step S101: Obtain the operating mode of the HVAC system, where the operating mode is one of the cooling mode and the heating mode;

[0109] Step S102: Determine that the heat source side heat exchanger is a condenser according to the operating mode being the cooling mode, or confirm that the load side heat exchanger is a condenser according to the operating mode being the heating mode;

[0110] Step S103: Determine the target subcooling degree of the condenser according to the middle temperature of the condenser and the ambient temperature;

[0111] Step S104: Determine the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser;

[0112] Step S105: Adjust the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range.

[0113] In the cooling mode, the heat source side heat exchanger is a condenser, and the ambient temperature is the outdoor temperature. In the heating mode, the load side heat exchanger is a condenser, and the ambient temperature is the indoor temperature.

[0114] The middle temperature of the condenser refers to the temperature in the middle of the condenser coil, and the outlet temperature of the condenser refers to the temperature at the outlet of the condenser coil.

[0115] The subcooling degree of the condenser refers to the difference in which the refrigerant liquid is cooled below the saturation temperature under the condensation pressure in the condenser. The subcooling degree can enable the refrigerant to absorb more heat in the evaporator, increase the refrigeration capacity per unit mass of the refrigerant, reduce the power consumption of the compressor, and improve the performance coefficient of the HVAC system.

[0116] The above step S103 can be specifically implemented as: determining the product of the difference between the middle temperature of the condenser and the ambient temperature and a preset coefficient as the target subcooling degree of the condenser.

[0117] Specifically, the value range of the above preset coefficient is determined according to the environment where the condenser is located. For example, in the cooling mode, the environment where the condenser is located is outdoor, and the value range of the preset coefficient includes 0.3 - 0.6. In the heating mode, the environment where the condenser is located is indoor, and the value range of the preset coefficient includes 0.5 - 0.8.

[0118] In the cooling mode, detect the outdoor temperature T1, the middle temperature T2 and the outlet temperature T3 of the heat source side heat exchanger. The target subcooling degree is SCS_c, and SCS_c is recommended to be (0.3 - 0.6)*(T2 - T1).

[0119] In the heating mode, the indoor temperature T4, the temperature T5 at the middle of the load-side heat exchanger, and the outlet temperature T6 are detected. The target subcooling degree is SCS_h, and SCS_h is preferably (0.5 - 0.8) * (T5 - T4).

[0120] In some embodiments, the above method of the present application further includes the step of correcting the target subcooling degree according to the exhaust temperature of the compressor, specifically including:

[0121] When the exhaust temperature of the compressor is within the second preset range, keep the current target subcooling degree unchanged; when the exhaust temperature of the compressor is outside the second preset range, increase or decrease the target subcooling degree until the exhaust temperature is within the second preset range.

[0122] Specifically, the step of increasing or decreasing the target subcooling degree according to the exhaust temperature of the compressor being outside the second preset range can be implemented as:

[0123] When the exhaust temperature of the compressor is greater than or equal to the upper limit of the second preset range, decrease the target subcooling degree by the first preset step; when the exhaust temperature of the compressor is less than or equal to the lower limit of the second preset range, increase the target subcooling degree by the first preset step.

[0124] The value range of the upper limit of the above second preset range includes 95 - 105 degrees Celsius; the environment where the condenser is located is outdoors, and the value range of the lower limit of the second preset range includes outdoor temperature + 15 degrees Celsius to outdoor temperature + 25 degrees Celsius; the environment where the condenser is located is indoors, and the value range of the lower limit of the second preset range includes indoor temperature + 25 degrees Celsius to indoor temperature + 35 degrees Celsius. The value range of the first preset step includes 1 - 2 degrees Celsius.

[0125] As Figure 6A shown, the heat source-side heat exchanger is a condenser, the upper limit of the second preset range is A, the lower limit is B, the exhaust temperature of the compressor is Tp, and the first preset step is ΔSC. The values of A and B are given values, and the range is preferably 95°C < A < 105°C, outdoor temperature + 15°C < B < outdoor temperature + 25°C. According to Figure 6A the shown process, correct the target subcooling degree SCS_c of the outdoor environment.

[0126] As Figure 6B shown, the load-side heat exchanger is a condenser, the upper limit of the second preset range is C, the lower limit is D, the exhaust temperature of the compressor is Tp, and the first preset step is ΔSC. The values of C and D are given values, and the range is preferably 95°C < C < 105°C, indoor temperature + 25°C < D < indoor temperature + 35°C. According to Figure 6B the shown process, correct the target subcooling degree SCS_h of the indoor environment.

[0127] In the above step S104, the actual subcooling degree of the condenser is the difference between the middle temperature and the outlet temperature of the condenser.

[0128] The heat source side heat exchanger is the condenser, and the actual subcooling degree SC_c = T2 - T3. The refrigerant flow rate in the HVAC system is adjusted by controlling the opening degree of the heat source side flow regulating valve, so that the difference between the actual subcooling degree SC_c and the target subcooling degree SCS_c is within the first preset range.

[0129] The load side heat exchanger is the condenser, and the actual subcooling degree SC_h = T2 - T2A. The refrigerant flow rate in the HVAC system is adjusted by controlling the opening degree of the heat source side flow regulating valve, so that the difference between the actual subcooling degree SC_h and the target subcooling degree SCS_h is within the first preset range.

[0130] Specifically, the above step S105 can be implemented as follows:

[0131] Keep the current refrigerant flow rate unchanged according to the difference between the actual subcooling degree minus the target subcooling degree being within the first preset range;

[0132] According to the difference between the actual subcooling degree minus the target subcooling degree being outside the first preset range, increase or decrease the refrigerant flow rate until the difference is within the first preset range.

[0133] Specifically, the step of increasing or decreasing the refrigerant flow rate according to the difference between the actual subcooling degree minus the target subcooling degree being outside the first preset range can be implemented as:

[0134] According to the difference between the actual subcooling degree minus the target subcooling degree being greater than or equal to the upper limit of the first preset range, increase the refrigerant flow rate at the second preset step; according to the difference between the actual subcooling degree minus the target subcooling degree being less than or equal to the lower limit of the first preset range, decrease the refrigerant flow rate at the second preset step.

[0135] The above first preset range can include -1 to 1 degree Celsius.

[0136] As Figure 7A shown, confirm that the condenser is the heat source side heat exchanger, the upper limit of the first preset range is 1, the lower limit is -1, the opening degree of the heat source side flow regulating valve is EXV, and the second preset step is ΔEXV. According to Figure 7A shown in the process, adjust the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree SC_c and the target subcooling degree SCS_c is within the range of -1 to 1 degree Celsius.

[0137] As Figure 7B shown, confirm that the condenser is the load side heat exchanger, the upper limit of the first preset range is 1, the lower limit is -1, the opening degree of the heat source side flow regulating valve is EXV, and the second preset step is ΔEXV. According toFigure 7B The process shown adjusts the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree SC_h and the target subcooling degree SCS_h is within the range of -1 to 1 degree Celsius.

[0138] It can be seen that in this application, the target subcooling degree is determined based on the ambient temperature and the middle temperature of the condenser, and then the refrigerant flow rate is adjusted to make the actual subcooling degree close to the target subcooling degree, so that the refrigerant amount matches the operating mode, improving the reliability and stability of the HVAC system.

[0139] The control method of the HVAC system in the embodiment of this application determines the target subcooling degree of the condenser according to the middle temperature and the ambient temperature of the condenser; determines the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser; adjusts the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range. Compared with the prior art, this application controls the refrigerant flow rate in the system according to the subcooling degree of the condenser, ensuring that the effective refrigerant amount in the system is in the best state, thereby being able to significantly reduce the capacity attenuation ratio of the system during long piping.

[0140] Embodiment Two

[0141] The embodiment of this application provides a control device for an HVAC system. This control device for the HVAC system corresponds to the control method of the HVAC system in Embodiment One. For related parts, refer to the partial description in Embodiment One. The method embodiments described below are only illustrative.

[0142] Figure 8 is a schematic diagram of a control device for an HVAC system provided by the embodiment of this application. As Figure 8 shown, the device 10 includes:

[0143] An acquisition module 101, configured to acquire the operating mode of the HVAC system, where the operating mode is one of a refrigeration mode and a heating mode; determine that the heat source side heat exchanger is a condenser according to the refrigeration mode, or confirm that the load side heat exchanger is a condenser according to the heating mode;

[0144] A determination module 102, configured to determine the target subcooling degree of the condenser according to the middle temperature and the ambient temperature of the condenser; determine the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser;

[0145] An adjustment module 103, configured to adjust the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range.

[0146] In a possible implementation manner, the determining module 101 is specifically configured to:

[0147] Determine the target subcooling degree of the condenser as the product of the difference between the middle temperature of the condenser and the ambient temperature where it is located and a preset coefficient.

[0148] In a possible implementation manner, the value range of the preset coefficient is determined according to the environment where the condenser is located.

[0149] In a possible implementation manner, when the condenser is a heat source side heat exchanger, the value range of the preset coefficient includes 0.3 to 0.6; when the condenser is a load side heat exchanger, the value range of the preset coefficient includes 0.5 to 0.8.

[0150] In a possible implementation manner, the determining module 101 is further configured to: before adjusting the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system, correct the target subcooling degree according to the exhaust temperature of the compressor.

[0151] In a possible implementation manner, the determining module 101 is specifically configured to:

[0152] Keep the current target subcooling degree unchanged according to the exhaust temperature being within a second preset range;

[0153] Increase or decrease the target subcooling degree according to the exhaust temperature being outside the second preset range until the exhaust temperature is within the second preset range.

[0154] In a possible implementation manner, the determining module 101 is specifically configured to:

[0155] Decrease the target subcooling degree by a first preset step according to the exhaust temperature being greater than or equal to the upper limit of the second preset range;

[0156] Increase the target subcooling degree by a first preset step according to the exhaust temperature being less than or equal to the lower limit of the second preset range.

[0157] In a possible implementation manner, the value range of the upper limit of the second preset range includes 95 to 105 degrees Celsius;

[0158] When the environment where the condenser is located is outdoors, the value range of the lower limit of the second preset range includes the outdoor temperature + 15 degrees Celsius to the outdoor temperature + 25 degrees Celsius;

[0159] When the environment where the condenser is located is indoors, the value range of the lower limit of the second preset range includes the indoor temperature + 25 degrees Celsius to the indoor temperature + 35 degrees Celsius.

[0160] In a possible implementation, the value range of the first preset step size includes 1 to 2 degrees Celsius.

[0161] In a possible implementation, the adjustment module 102 is specifically configured to:

[0162] Keep the current refrigerant flow rate unchanged according to the difference being within the first preset range;

[0163] Increase or decrease the refrigerant flow rate according to the difference being outside the first preset range until the difference is within the first preset range.

[0164] In a possible implementation, the adjustment module 102 is specifically configured to:

[0165] Increase the refrigerant flow rate according to the second preset step size according to the difference being greater than or equal to the upper limit of the first preset range;

[0166] Decrease the refrigerant flow rate according to the second preset step size according to the difference being less than or equal to the lower limit of the first preset range.

[0167] In a possible implementation, the first preset range includes -1 to 1 degree Celsius.

[0168] In a possible implementation, the adjustment module 102 is specifically configured to:

[0169] Adjust the refrigerant flow rate in the HVAC system by controlling the opening degree of the flow regulating valve on the heat source side.

[0170] Embodiment III

[0171] The embodiment of the present application also provides a computer-readable storage medium, on which computer-readable instructions are stored, and the computer-readable instructions can be executed by a processor to implement the control method of the HVAC system in any implementation manner in Embodiment I.

[0172] Examples of the computer-readable storage medium may also include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other optical and magnetic storage media, which will not be elaborated here one by one.

[0173] The computer-readable storage medium provided in the above embodiment of the present application and the control method of the HVAC system provided in the embodiment of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run, or implemented by the application programs stored therein.

[0174] It should be noted that:

[0175] In the specification provided herein, a large number of specific details are set forth. However, it will be understood that embodiments of the present application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0176] Similarly, it should be understood that in order to streamline the present application and assist in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed subject matter of the present application requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all of the features of the single foregoing embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the present application.

[0177] Those skilled in the art will appreciate that the modules in the devices in the embodiments can be adaptively changed and disposed in one or more devices different from those of the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and in addition, they can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all the features disclosed in this specification (including the accompanying claims, abstract and drawings) and all the processes or units of any method or device so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract and drawings) can be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0178] In addition, those skilled in the art will be able to understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0179] It should be noted that the above embodiments are illustrative of the present application rather than limiting the present application, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present application can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim listing several devices, several of these devices may be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words may be interpreted as names.

[0180] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A heating, ventilation and air conditioning (HVAC) system, characterized in that, The HVAC system includes: a heat source side heat exchanger, a load side heat exchanger, a heat source side flow regulating valve, and a control module for controlling the HVAC system. The control module includes a control method, and the method includes: Obtain the operating mode of the HVAC system, where the operating mode is one of a cooling mode and a heating mode; Determine that the heat source side heat exchanger is a condenser according to the operating mode being the cooling mode, or confirm that the load side heat exchanger is a condenser according to the operating mode being the heating mode; Determine the target subcooling degree of the condenser according to the middle temperature and the ambient temperature of the condenser; Determine the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser; Adjust the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system, so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range.

2. The HVAC system according to claim 1, characterized in that, The determining the target subcooling degree of the condenser according to the middle temperature and the ambient temperature of the condenser includes: Determine the product of the difference between the middle temperature and the ambient temperature of the condenser and a preset coefficient as the target subcooling degree of the condenser.

3. The HVAC system according to claim 2, characterized in that, The value range of the preset coefficient is determined according to the environment where the condenser is located.

4. The HVAC system according to claim 3, wherein Confirm that the condenser is the heat source side heat exchanger, and the value range of the preset coefficient includes 0.3 to 0.6; Confirm that the condenser is the load side heat exchanger, and the value range of the preset coefficient includes 0.5 to 0.

8.

5. The HVAC system according to claim 1, wherein, Before the adjusting the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system, the method further includes: Correct the target subcooling degree according to the exhaust temperature of the compressor.

6. The HVAC system according to claim 5, wherein The correcting the target subcooling degree according to the exhaust temperature of the compressor includes: Keep the current target subcooling degree unchanged according to the exhaust temperature being within a second preset range; Increase or decrease the target subcooling degree according to the exhaust temperature being outside the second preset range until the exhaust temperature is within the second preset range.

7. The HVAC system according to claim 6, characterized in that, The increasing or decreasing the target subcooling degree according to the exhaust temperature being outside the second preset range includes: Decrease the target subcooling degree by a first preset step according to the exhaust temperature being greater than or equal to the upper limit of the second preset range; Increase the target subcooling degree by a first preset step according to the exhaust temperature being less than or equal to the lower limit of the second preset range.

8. The HVAC system according to claim 7, characterized in that, The value range of the upper limit of the second preset range includes 95 to 105 degrees Celsius; When the environment where the condenser is located is outdoors, the value range of the lower limit of the second preset range includes outdoor temperature + 15 degrees Celsius to outdoor temperature + 25 degrees Celsius; When the environment where the condenser is located is indoors, the value range of the lower limit of the second preset range includes indoor temperature + 25 degrees Celsius to indoor temperature + 35 degrees Celsius.

9. The HVAC system according to claim 7, wherein The value range of the first preset step includes 1 to 2 degrees Celsius.

10. The HVAC system according to claim 1, characterized in that, The adjusting the refrigerant flow rate in the HVAC system so that the difference between the actual subcooling degree and the target subcooling degree is within a first preset range includes: If the difference is within the first preset range, keep the current refrigerant flow rate unchanged; If the difference is outside the first preset range, increase or decrease the refrigerant flow rate until the difference is within the first preset range.

11. The HVAC system according to claim 10, wherein The increasing or decreasing of the refrigerant flow rate when the difference is outside the first preset range includes: If the difference is greater than or equal to the upper limit of the first preset range, increase the refrigerant flow rate in accordance with a second preset step size; If the difference is less than or equal to the lower limit of the first preset range, decrease the refrigerant flow rate in accordance with a second preset step size.

12. The HVAC system according to claim 1, wherein The first preset range includes -1 to 1 degree Celsius.

13. A heating, ventilation and air conditioning system, characterized in that, The HVAC system includes: a heat source side heat exchanger, a load side heat exchanger, a heat source side flow regulating valve, and a control module for controlling the HVAC system. The control module includes a control device, and the device includes: An acquisition module, configured to acquire the operating mode of the HVAC system, where the operating mode is one of a refrigeration mode and a heating mode; and determine that the heat source side heat exchanger is a condenser according to the operating mode being the refrigeration mode, or confirm that the load side heat exchanger is a condenser according to the operating mode being the heating mode; A determination module, configured to determine the target subcooling degree of the condenser according to the middle temperature and the ambient temperature of the condenser; and determine the actual subcooling degree of the condenser according to the middle temperature and the outlet temperature of the condenser; An adjustment module, configured to adjust the opening degree of the heat source side flow regulating valve to control the refrigerant flow rate in the HVAC system, so that the difference between the actual subcooling degree and the target subcooling degree is within the first preset range.

14. A computer-readable storage medium, characterized in that, It stores computer-readable instructions, and the computer-readable instructions can be executed by a processor to implement the control method according to any one of claims 1 to 12.

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