Composite air conditioning system and electronic expansion valve opening control method

Abstract

The present invention relates to the technical field of air conditioning, and discloses a composite air conditioning system and an electronic expansion valve opening control method. The method aims to address the poor user comfort problem of existing composite air conditioning systems. The composite air conditioning system comprises a control unit, an outdoor unit, an intermediate heat exchange unit, a water circuit unit, and an indoor unit. The outdoor unit comprises a compressor and an electronic expansion valve, and the intermediate heat exchange unit comprises a shell-and-tube heat exchanger, a water tank, and a water pump. The compressor exhaust port is connected to the compressor intake port via the electronic expansion valve, the shell-and-tube heat exchanger, and the indoor unit in sequence. Both ends of the water tank are connected to the water circuit unit via water pipes. The water pump is connected in series to the water pipes, which are coupled to the shell-and-tube heat exchanger. The method comprises: after the air conditioner starts cooling mode, the control unit performs incremental opening compensation on the electronic expansion valve, so that the evaporation temperature of the water circuit unit increases and the evaporation temperature of the indoor unit is at a target evaporation temperature. The present invention improves user comfort.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a composite air conditioning system and an opening control method of an electronic expansion valve. Background Art

[0002] Air conditioners, as a household indoor temperature control system, have become widespread in consumers' homes. Split-type air conditioners consist of an indoor unit and an outdoor unit. Existing indoor units provide cooling or heating to the room by blowing cold or hot air outward through an air outlet. However, since the cold or hot air is blown directly from the air conditioner's outlet, it can cause discomfort to the user and affect the user experience. Furthermore, convective heat transfer can cause significant temperature gradients and uneven temperature distribution in the room.

[0003] Application publication number CN109945545A discloses a loop heat pipe refrigeration and air-conditioning system. Its main technical solution is to transfer the heat generated by the heating or refrigeration cycle of the air-conditioning system to the loop heat pipe unit through an intermediate heat exchange unit, and perform heat exchange through a loop heat pipe heat transfer device. Since the heat pipe has high heat exchange efficiency and the heat pipe can be evenly arranged under the indoor floor, a very comfortable heat exchange effect can be obtained and a windless effect can be achieved.

[0004] While this approach can achieve a windless effect, the intermediate heat exchanger itself, as a piping device with a closed structure, exerts a certain throttling effect when placed in the refrigeration circuit. The two evaporators connected in series inevitably experience an increasing pressure drop within the refrigeration circuit, an effect known as continuous pressure drop. Furthermore, in practical applications, to better meet users' actual physiological needs and enhance user comfort, the evaporation temperature of the loop heat pipe heat transfer device must be higher than the indoor dew point, while the evaporation temperature of the indoor unit must be lower than the indoor dew point. This ensures that the loop heat pipe heat transfer device provides the primary cooling capacity through radiative heat exchange, while the indoor unit air-cooled system provides the secondary cooling capacity through convective heat exchange, while maintaining dehumidification in the indoor unit. This ideal state is considered ideal. Based on this, assuming the indoor unit is placed downstream of the loop heat pipe heat transfer device, if the indoor unit needs to maintain dehumidification, the evaporation temperature of the indoor unit needs to be lowered. This will lower the evaporation temperature of the loop heat pipe heat transfer device, and thus the floor temperature, which can easily cause irritation when people touch or step on it. In this case, the indoor unit cannot achieve the standard refrigerant flow and pressure, affecting the user's comfort. If the indoor unit is placed upstream of the loop heat pipe heat transfer device, if the indoor unit needs to maintain dehumidification, the evaporation temperature of the downstream loop heat pipe heat transfer device will be even lower due to the continuous pressure drop. Combined with the high heat exchange capacity of the loop heat pipe heat transfer device, the entire floor temperature will reach a very low level, further affecting the user's comfort. Summary of the Invention

[0005] The present invention aims to solve the problem of poor user comfort in existing composite air conditioners and proposes a composite air conditioning system and an opening control method of an electronic expansion valve.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] In a first aspect, a method for controlling the opening of an electronic expansion valve is provided, which is applied to a composite air-conditioning system. The composite air-conditioning system includes: a control unit, an outdoor unit, an intermediate heat exchange unit, a water circuit unit, and an indoor unit; the outdoor unit includes: a compressor and an electronic expansion valve; the intermediate heat exchange unit includes: a shell-and-tube heat exchanger, a water tank, and a water pump; the exhaust port of the compressor is connected to the intake port of the compressor via the electronic expansion valve, the shell-and-tube heat exchanger, and the indoor unit in sequence; both ends of the water tank are connected to the water circuit unit via water pipes; the water pump is connected in series to the water pipes, and the water pipes are coupled to the shell-and-tube heat exchanger; the method includes:

[0008] After the air conditioner starts the cooling mode, the control unit performs opening increment compensation on the electronic expansion valve, so that the evaporation temperature of the water path unit increases and the evaporation temperature of the indoor unit is at a target evaporation temperature.

[0009] Furthermore, the performing opening increment compensation on the electronic expansion valve specifically includes:

[0010] Obtaining a corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve;

[0011] determining a corresponding optimal compensation increment according to the current operating frequency of the compressor and based on the corresponding relationship;

[0012] The opening increment compensation is performed on the electronic expansion valve according to the optimal compensation increment.

[0013] Furthermore, obtaining the corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve specifically includes:

[0014] Under the experimental environment, the compressor is operated at different operating frequencies, and the electronic expansion valve is repeatedly debugged at each operating frequency of the compressor until the evaporation temperature of the indoor unit reaches the target evaporation temperature, and the corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve is obtained.

[0015] Furthermore, when the evaporating temperature of the indoor unit is at the target evaporating temperature, the indoor unit performs cooling and dehumidification simultaneously.

[0016] Furthermore, the performing of opening increment compensation on the electronic expansion valve specifically includes:

[0017] Obtaining a first functional relationship between an evaporating temperature of the indoor unit and an opening of the electronic expansion valve in a single-indoor-unit air-conditioning mode, wherein the single-indoor-unit air-conditioning mode is configured such that a shell-and-tube heat exchanger is removed, an exhaust port of the compressor is connected to an intake port of the compressor via the electronic expansion valve and the indoor unit in sequence, and cooling is performed only by the indoor unit;

[0018] Obtaining a second functional relationship between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve in a combined air-conditioning mode, wherein the combined air-conditioning mode refers to simultaneously starting the indoor unit and the water circuit unit for cooling;

[0019] The opening increment compensation of the electronic expansion valve is performed according to the first functional relationship and the second functional relationship.

[0020] Furthermore, performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship specifically includes:

[0021] After the air conditioner starts the cooling mode and runs stably, the current opening of the electronic expansion valve is obtained, the current opening is substituted into the first functional relationship to obtain the target evaporating temperature of the indoor unit, the target evaporating temperature is substituted into the second functional relationship to obtain the target opening of the electronic expansion valve, and the electronic expansion valve is adjusted to the target opening.

[0022] Furthermore, performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship specifically includes:

[0023] determining a third functional relationship between the evaporation temperature of the indoor unit and the adjustment step number of the electronic expansion valve in the combined air-conditioning mode according to the first functional relationship and the second functional relationship;

[0024] After the air conditioner starts the cooling mode and runs stably, the current evaporating temperature of the indoor unit is obtained, the current evaporating temperature is substituted into the third function relationship to obtain the target adjustment step number of the electronic expansion valve, and the opening increment compensation of the electronic expansion valve is performed according to the target adjustment step number.

[0025] In a second aspect, a composite air conditioning system is provided, comprising: a control unit, an outdoor unit, an intermediate heat exchange unit, a water circuit unit, and an indoor unit; the outdoor unit comprising: a compressor and an electronic expansion valve; the intermediate heat exchange unit comprising: a shell-and-tube heat exchanger, a water tank, and a water pump; the exhaust port of the compressor is connected to the intake port of the compressor via the electronic expansion valve, the shell-and-tube heat exchanger, and the indoor unit in sequence; both ends of the water tank are connected to the water circuit unit via water pipes; the water pump is connected in series to the water pipes, and the water pipes are coupled to the shell-and-tube heat exchanger;

[0026] The control unit is used to perform opening increment compensation on the electronic expansion valve after the air conditioner starts the cooling mode, so that the evaporation temperature of the water circuit unit increases and the evaporation temperature of the indoor unit is at the target evaporation temperature.

[0027] Furthermore, the control unit is specifically configured to:

[0028] Obtain a correspondence between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve, determine a corresponding optimal compensation increment according to the current operating frequency of the compressor and based on the correspondence, and perform incremental compensation for the opening of the electronic expansion valve according to the optimal compensation increment.

[0029] Furthermore, the control unit is further configured to:

[0030] Obtaining a first functional relationship between an evaporating temperature of the indoor unit and an opening of the electronic expansion valve in a single-indoor-unit air-conditioning mode, wherein the single-indoor-unit air-conditioning mode is configured such that a shell-and-tube heat exchanger is removed, an exhaust port of the compressor is connected to an intake port of the compressor via the electronic expansion valve and the indoor unit in sequence, and cooling is performed only by the indoor unit;

[0031] Obtaining a second functional relationship between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve in a combined air-conditioning mode, wherein the combined air-conditioning mode refers to simultaneously starting the indoor unit and the water circuit unit for cooling;

[0032] The opening increment compensation of the electronic expansion valve is performed according to the first functional relationship and the second functional relationship.

[0033] The beneficial effects of the present invention are as follows: the combined air conditioning system and electronic expansion valve opening control method described herein couple the water circuit unit to the upstream of the indoor unit via an intermediate heat exchange unit. After the air conditioner is in cooling mode, incremental opening compensation is performed on the electronic expansion valve, thereby increasing the evaporation temperature of the water circuit unit, thereby increasing the indoor floor temperature. Simultaneously, the continuous pressure drop caused by the throttling effect ensures that the evaporation temperature of the indoor unit precisely reaches the target evaporation temperature, thereby allowing the indoor unit to precisely match the standard state, thereby improving user comfort. Furthermore, the indoor unit can be simultaneously in cooling mode and weak dehumidification mode, achieving a balance between increasing the floor temperature and maintaining the dehumidification effect of the indoor unit. This not only increases the floor temperature but also allows the indoor unit to maintain a weak dehumidification effect, further improving user comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic structural diagram of a composite air-conditioning system according to an embodiment of the present invention;

[0035] Figure 2A schematic diagram of corresponding data between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve according to an embodiment of the present invention;

[0036] Figure 3 Schematic diagram of a first functional relationship curve and a second functional relationship curve between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve according to an embodiment of the present invention;

[0037] Figure 4 Schematic diagram of a third functional relationship curve between the evaporation temperature of the indoor unit and the adjustment steps of the electronic expansion valve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] The present invention aims to improve user comfort and proposes a composite air-conditioning system and an opening control method of an electronic expansion valve. The composite air-conditioning system includes: a control unit, an outdoor unit unit, an intermediate heat exchange unit, a water circuit unit and an indoor unit unit; the outdoor unit unit includes: a compressor and an electronic expansion valve, the intermediate heat exchange unit includes: a shell and tube heat exchanger, a water tank and a water pump, the exhaust port of the compressor is connected to the intake port of the compressor through the electronic expansion valve, the shell and tube heat exchanger and the indoor unit unit in sequence, the two ends of the water tank are connected to the water circuit unit through water pipes, the water pump is connected in series to the water pipe, and the water pipe is coupled to the shell and tube heat exchanger; the method includes: after the air conditioner starts the cooling mode, the control unit performs opening increment compensation on the electronic expansion valve, so that the evaporation temperature of the water circuit unit increases and the evaporation temperature of the indoor unit is at the target evaporation temperature.

[0040] It is understood that in a hybrid air conditioning system, the throttling effect of the intermediate heat exchange unit inevitably causes a gradual pressure drop in the refrigeration circuit between the two evaporators, the water circuit unit and the indoor unit, connected in series. This is particularly true when the indoor unit is located downstream of the water circuit unit. This can cause the actual evaporation temperature of the indoor unit to be lower than the evaporation temperature under standard conditions, which refers to cooling with a single indoor unit. Furthermore, to maintain the dehumidification effect of the indoor unit, the evaporation temperature of the indoor unit needs to be lowered, but this also lowers the evaporation temperature of the water circuit unit, resulting in a lower floor temperature. To address this issue, the present invention couples the water circuit unit upstream of the indoor unit via the intermediate heat exchange unit. When the air conditioner is in cooling mode, the electronic expansion valve performs incremental opening compensation, increasing the evaporation temperature of the water circuit unit and, in turn, the indoor floor temperature. Furthermore, the continuous pressure drop caused by the throttling effect allows the evaporation temperature of the indoor unit to precisely reach the target evaporation temperature, thereby ensuring that the indoor unit is precisely aligned with the standard condition and improving user comfort. In addition, the indoor unit can be in cooling mode and weak dehumidification mode at the same time, achieving a balance between increasing the floor temperature and maintaining the dehumidification effect of the indoor unit. That is, it not only increases the floor temperature, but also enables the indoor unit to maintain a weak dehumidification effect, further improving user comfort.

[0041] Example

[0042] See also Figure 1 The composite air-conditioning system according to an embodiment of the present invention includes: a control unit, an outdoor unit, an intermediate heat exchange unit, a water circuit unit and an indoor unit; the outdoor unit includes: a compressor and an electronic expansion valve; the intermediate heat exchange unit includes: a shell and tube heat exchanger, a water tank and a water pump; the exhaust port of the compressor is connected to the air intake port of the compressor through the electronic expansion valve, the shell and tube heat exchanger and the indoor unit in sequence; both ends of the water tank are connected to the water circuit unit through water pipes; the water pump is connected in series to the water pipe, and the water pipe is coupled to the shell and tube heat exchanger.

[0043] Specifically, in this embodiment, the water path unit is coupled to the upstream of the indoor unit through an intermediate heat exchange unit, wherein the flow direction of the refrigerant is: compressor exhaust port → electronic expansion valve → shell and tube heat exchanger → indoor unit unit → compressor intake port, and the water path flow direction is: water tank → water distributor → water pipe → water collector → water pump → shell and tube heat exchanger → water tank. The water pipes are distributed under the floor. In the shell and tube heat exchanger, the refrigerant exchanges heat with water, thereby realizing simultaneous cooling of the indoor unit unit and the water path unit.

[0044] Based on the above-mentioned composite air-conditioning system, the present embodiment provides a method for controlling the opening of an electronic expansion valve, including:

[0045] After the air conditioner starts the cooling mode, the control unit performs opening increment compensation on the electronic expansion valve, so that the evaporation temperature of the water path unit increases and the evaporation temperature of the indoor unit is at the target evaporation temperature.

[0046] In this embodiment, the method for performing opening increment compensation on the electronic expansion valve may be:

[0047] Step 101: Obtain a corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve;

[0048] Specifically, in an experimental environment, the compressor can be operated at different operating frequencies. The electronic expansion valve can be repeatedly adjusted at each compressor operating frequency until the evaporation temperature of the indoor unit reaches the target evaporation temperature. This can determine the opening degree of the electronic expansion valve at different compressor operating frequencies, and further determine the corresponding relationship between the compressor operating frequency and the optimal compensation increment of the electronic expansion valve. The target evaporation temperature can be the ideal evaporation temperature of the air conditioner when operating at that operating frequency, that is, the evaporation temperature of the indoor unit when operating in both cooling and weak dehumidification modes.

[0049] Step 102: determining a corresponding optimal compensation increment according to the current operating frequency of the compressor and based on the corresponding relationship;

[0050] After obtaining the correspondence between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve, the correspondence can be saved to the control unit. When the air conditioner is actually used in the future, the control unit can determine the corresponding optimal compensation increment based on the current operating frequency of the compressor and the correspondence.

[0051] Step 103: Perform opening increment compensation on the electronic expansion valve according to the optimal compensation increment.

[0052] After determining the optimal compensation increment, the optimal compensation increment is added to the original opening of the electronic expansion valve, thereby achieving incremental compensation for the opening of the electronic expansion valve.

[0053] This embodiment increases the evaporation temperature of the upstream water circuit unit by applying incremental compensation to the electronic expansion valve opening, thereby raising the floor temperature. Utilizing the principle of continuous pressure drop, the downstream indoor unit receives the same refrigerant flow and pressure as in standard conditions, ensuring the cooling capacity and efficiency of the indoor unit, thereby improving user comfort. Furthermore, the target evaporation temperature allows the indoor unit to operate in both cooling and weak dehumidification modes simultaneously, achieving a balance between raising the floor temperature and maintaining the indoor unit's dehumidification efficiency. This not only improves the floor temperature but also maintains a weak dehumidification effect, achieving the ideal state of a hybrid air conditioner and further improving user comfort.

[0054] In this embodiment, the method for performing opening increment compensation on the electronic expansion valve may also be:

[0055] Step 201: Obtain a first functional relationship between the evaporation temperature of the indoor unit and the opening of the electronic expansion valve in a single-indoor-unit air-conditioning mode. The single-indoor-unit air-conditioning mode is a mode in which the double-tube heat exchanger is removed, the exhaust port of the compressor is connected to the intake port of the compressor via the electronic expansion valve and the indoor unit in sequence, and cooling is performed only by the indoor unit.

[0056] Specifically, in an experimental environment, the water cooling part can be completely removed, and cooling can be performed only through the indoor unit. At this time, the refrigerant flow direction is: compressor exhaust port → electronic expansion valve → indoor unit → compressor air intake port, that is, single indoor unit air conditioning mode. In this mode, the cooling mode is turned on (i.e., standard state), and the electronic expansion valve is controlled at different opening degrees. At the same time, the evaporation temperature of the indoor heat exchanger of the indoor unit unit at different opening degrees is measured. The corresponding data obtained can be found in Figure 2 , and then fit the corresponding relationship into the first functional relationship.

[0057] Step 202: Obtain a second functional relationship between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve in a combined air-conditioning mode, wherein the combined air-conditioning mode is to simultaneously start the indoor unit and the water circuit unit for cooling;

[0058] Specifically, in an experimental environment, the indoor unit and the water circuit unit can be controlled to cool simultaneously, i.e., the combined air conditioning mode. In this mode, the cooling mode is turned on, and the electronic expansion valve is controlled to different openings. At the same time, the evaporation temperature of the indoor heat exchanger of the indoor unit unit at different openings is measured. The corresponding data obtained can be found in Figure 2 , and then fit the corresponding relationship into a second functional relationship.

[0059] Step 203: Perform opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship.

[0060] In this embodiment, the method for performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship may be:

[0061] After the air conditioner starts the cooling mode and runs stably, the current opening of the electronic expansion valve is obtained, the current opening is substituted into the first functional relationship to obtain the target evaporating temperature of the indoor unit, the target evaporating temperature is substituted into the second functional relationship to obtain the target opening of the electronic expansion valve, and the electronic expansion valve is adjusted to the target opening.

[0062] Specifically, the first functional relationship represents the correspondence between the electronic expansion valve opening and the target evaporating temperature in single-indoor unit air conditioning mode (standard conditions). The second functional relationship represents the correspondence between the electronic expansion valve opening and the actual evaporating temperature in combined air conditioning mode. After determining the current opening of the electronic expansion valve, the target evaporating temperature is obtained by substituting the current opening into the first functional relationship. The target evaporating temperature is then substituted into the second functional relationship to obtain the target opening of the electronic expansion valve. By adjusting the electronic expansion valve to the target opening, the indoor unit in combined air conditioning mode can reach the target evaporating temperature, achieving incremental compensation for the electronic expansion valve opening.

[0063] See also Figure 3 During actual air conditioning use, the cooling mode is started and stabilized for a certain period of time before reaching the compensation point (point A). The control unit obtains the current step number Sa of the electronic expansion valve and substitutes the current step number Sa into the first functional relationship to obtain the target evaporating temperature Tb in the single indoor unit air conditioning mode (point B). The target evaporating temperature Tb is then substituted into the second functional relationship to obtain the target opening Sc of the electronic expansion valve at the equivalent point (point C) in the combined air conditioning mode at the target evaporating temperature Tb. Since Sc is greater than Sa, the electronic expansion valve is considered to be too small and needs to be opened wider. The control unit directly sets the opening of the electronic expansion valve at this time to the step number Sc, thereby achieving incremental compensation of the electronic expansion valve opening.

[0064] In this embodiment, the air conditioner's stable operation is marked by the indoor temperature reaching the set temperature for the first time. Specifically, while the compressor is in the frequency ramp-up phase, incremental compensation control of the electronic expansion valve opening is not performed. Once the compressor reaches the frequency stabilization phase, incremental compensation control of the electronic expansion valve opening is performed.

[0065] It is understandable that the basic principle of variable-frequency air conditioners or any refrigeration equipment with a variable-frequency compressor is that when the air conditioner is first turned on, the difference between the indoor temperature and the set temperature is large, and the compressor frequency will become very high (in order to cool down the room as quickly as possible, but at the expense of energy). When the indoor temperature reaches the set temperature, the compressor frequency will be reduced to maintain a stable low-frequency stable state (energy saving). As long as the subsequent cooling load in the room does not change much, the system compressor will continue to operate in this state. Therefore, a single compensation adjustment can ensure that the system can continue to operate in an ideal state without considering the change in cooling load. Based on this, this embodiment does not perform compensation control when the composite air conditioning system is first turned on. This period of time does not last long, and it is time to consider how to quickly get the indoor temperature to the set temperature. Compensation control is to prevent the floor from being overcooled during the subsequent stabilization phase, not the frequency increase phase at startup. If compensation is performed at the beginning, the cooling speed will be slowed down, which does not meet the actual needs of users.

[0066] In this embodiment, the method for performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship may also be:

[0067] A third functional relationship between the evaporating temperature of the indoor unit and the adjustment step number of the electronic expansion valve in the compound air-conditioning mode is determined based on the first functional relationship and the second functional relationship; after the air-conditioning starts the cooling mode and runs stably, the current evaporating temperature of the indoor unit is obtained, the current evaporating temperature is substituted into the third functional relationship to obtain the target adjustment step number of the electronic expansion valve, and the opening increment compensation of the electronic expansion valve is performed according to the target adjustment step number.

[0068] Specifically, after obtaining the first functional relationship and the second functional relationship, the control unit can process the first functional relationship and the second functional relationship. Figure 3 The specific processing process is as follows: at points A and B of a certain opening Sa of the electronic expansion valve, the evaporation temperature Ta of the indoor unit in the single indoor unit air conditioning mode and the evaporation temperature Tb of the indoor unit in the combined air conditioning mode are obtained. The equivalent point C is found through Tb in the second functional relationship to obtain the target opening Sc of the equivalent point C. The target adjustment step number ΔS is then obtained by the difference between Sc and Sa. Similarly, the program calculates each opening of the electronic expansion valve one by one to obtain the corresponding data between the evaporation temperature Ta of the indoor unit and the adjustment step number ΔS of the electronic expansion valve, and fits them to a third functional relationship. The corresponding third functional relationship curve can be found in [ 1 ]. Figure 4 .

[0069] After obtaining the third functional relationship, the third functional relationship can be saved to the control unit. During subsequent actual use of the air conditioner, the control unit can then perform incremental opening compensation for the electronic expansion valve based on the current evaporating temperature of the indoor unit and the third functional relationship. Specifically, during actual use of the air conditioner, after starting cooling mode and operating stably for a certain period of time, the current evaporating temperature of the indoor unit is detected by a temperature sensor. The current evaporating temperature is substituted into the third functional relationship to obtain the number of adjustment steps for the electronic expansion valve. The incremental opening compensation for the electronic expansion valve is then performed based on the number of adjustment steps.

[0070] It should be noted that when the air conditioner is actually in use, the opening increment compensation of the electronic expansion valve will only be performed once after a certain period of stable operation, and no further adjustments will be made thereafter.

[0071] In summary, the hybrid air conditioning system and electronic expansion valve opening control method provided in this embodiment couples the water circuit unit to the upstream of the indoor unit via an intermediate heat exchange unit. After the air conditioner is in cooling mode, incremental opening compensation is performed on the electronic expansion valve, increasing the evaporation temperature of the water circuit unit, thereby raising the indoor floor temperature. Simultaneously, the continuous pressure drop caused by the throttling effect ensures that the evaporation temperature of the indoor unit precisely reaches the target evaporation temperature, thereby precisely matching the indoor unit's standard state and improving user comfort. Furthermore, the indoor unit can be simultaneously in cooling mode and weak dehumidification mode, achieving a balance between increasing the floor temperature and maintaining the indoor unit's dehumidification effect. This not only increases the floor temperature but also allows the indoor unit to maintain a weak dehumidification effect, further improving user comfort.

Claims

1. An electronic expansion valve opening control method, applied to a composite air conditioning system, is characterized in that: The composite air-conditioning system includes: a control unit, an outdoor unit, an intermediate heat exchange unit, a water circuit unit, and an indoor unit; the outdoor unit includes: a compressor and an electronic expansion valve; the intermediate heat exchange unit includes: a shell-and-tube heat exchanger, a water tank, and a water pump; the exhaust port of the compressor is connected to the air intake port of the compressor through the outdoor heat exchanger, the electronic expansion valve, the shell-and-tube heat exchanger, and the indoor unit in sequence; both ends of the water tank are connected to the water circuit unit through water pipes; the water pump is connected in series to the water pipes, and the water pipes are coupled to the shell-and-tube heat exchanger; the method includes: After the air conditioner starts the cooling mode, the control unit performs opening increment compensation on the electronic expansion valve so that the evaporation temperature of the water circuit unit increases and the evaporation temperature of the indoor unit is at the target evaporation temperature; The performing of opening increment compensation on the electronic expansion valve specifically includes: Obtaining a first functional relationship between an evaporating temperature of the indoor unit and an opening of the electronic expansion valve in a single-indoor-unit air-conditioning mode, wherein the single-indoor-unit air-conditioning mode is configured such that a shell-and-tube heat exchanger is removed, an exhaust port of the compressor is connected to an intake port of the compressor via the electronic expansion valve and the indoor unit in sequence, and cooling is performed only by the indoor unit; Obtaining a second functional relationship between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve in a combined air-conditioning mode, wherein the combined air-conditioning mode refers to simultaneously starting the indoor unit and the water circuit unit for cooling; performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship; Performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship specifically includes: determining a third functional relationship between the evaporation temperature of the indoor unit and the adjustment step number of the electronic expansion valve in the combined air-conditioning mode according to the first functional relationship and the second functional relationship; After the air conditioner starts the cooling mode and runs stably, the current evaporating temperature of the indoor unit is obtained, the current evaporating temperature is substituted into the third function relationship to obtain the target adjustment step number of the electronic expansion valve, and the opening increment compensation of the electronic expansion valve is performed according to the target adjustment step number.

2. The method for controlling the opening of an electronic expansion valve according to claim 1, wherein: The performing of opening increment compensation on the electronic expansion valve specifically includes: Obtaining a corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve; determining a corresponding optimal compensation increment according to the current operating frequency of the compressor and based on the corresponding relationship; The opening increment compensation is performed on the electronic expansion valve according to the optimal compensation increment.

3. The method for controlling the opening of an electronic expansion valve according to claim 2, wherein: The obtaining of the corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve specifically includes: Under the experimental environment, the compressor is operated at different operating frequencies, and the electronic expansion valve is repeatedly debugged at each operating frequency of the compressor until the evaporation temperature of the indoor unit reaches the target evaporation temperature, and the corresponding relationship between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve is obtained.

4. The method for controlling the opening of an electronic expansion valve according to any one of claims 1 to 3, wherein: When the evaporating temperature of the indoor unit is at the target evaporating temperature, the indoor unit performs cooling and dehumidification simultaneously.

5. The method for controlling the opening of an electronic expansion valve according to claim 1, wherein: Performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship specifically includes: After the air conditioner starts the cooling mode and runs stably, the current opening of the electronic expansion valve is obtained, the current opening is substituted into the first functional relationship to obtain the target evaporating temperature of the indoor unit, the target evaporating temperature is substituted into the second functional relationship to obtain the target opening of the electronic expansion valve, and the electronic expansion valve is adjusted to the target opening.

6. A composite air conditioning system, characterized in that: The composite air-conditioning system includes: a control unit, an outdoor unit, an intermediate heat exchange unit, a water circuit unit, and an indoor unit; the outdoor unit includes: a compressor and an electronic expansion valve; the intermediate heat exchange unit includes: a shell-and-tube heat exchanger, a water tank, and a water pump; the exhaust port of the compressor is connected to the air intake port of the compressor through the outdoor heat exchanger, the electronic expansion valve, the shell-and-tube heat exchanger, and the indoor unit in sequence; both ends of the water tank are connected to the water circuit unit through water pipes; the water pump is connected in series to the water pipes, and the water pipes are coupled to the shell-and-tube heat exchanger; The control unit is used to perform opening increment compensation on the electronic expansion valve after the air conditioner starts the cooling mode, so that the evaporation temperature of the water circuit unit increases and the evaporation temperature of the indoor unit is at the target evaporation temperature; The performing of opening increment compensation on the electronic expansion valve specifically includes: Obtaining a first functional relationship between an evaporating temperature of the indoor unit and an opening of the electronic expansion valve in a single-indoor-unit air-conditioning mode, wherein the single-indoor-unit air-conditioning mode is configured such that a shell-and-tube heat exchanger is removed, an exhaust port of the compressor is connected to an intake port of the compressor via the electronic expansion valve and the indoor unit in sequence, and cooling is performed only by the indoor unit; Obtaining a second functional relationship between the evaporation temperature of the indoor unit and the opening degree of the electronic expansion valve in a combined air-conditioning mode, wherein the combined air-conditioning mode refers to simultaneously starting the indoor unit and the water circuit unit for cooling; performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship; Performing opening increment compensation on the electronic expansion valve according to the first functional relationship and the second functional relationship specifically includes: determining a third functional relationship between the evaporation temperature of the indoor unit and the adjustment step number of the electronic expansion valve in the combined air-conditioning mode according to the first functional relationship and the second functional relationship; After the air conditioner starts the cooling mode and runs stably, the current evaporating temperature of the indoor unit is obtained, the current evaporating temperature is substituted into the third function relationship to obtain the target adjustment step number of the electronic expansion valve, and the opening increment compensation of the electronic expansion valve is performed according to the target adjustment step number.

7. The composite air conditioning system according to claim 6, wherein: The control unit is specifically used for: Obtain a correspondence between the operating frequency of the compressor and the optimal compensation increment of the electronic expansion valve, determine a corresponding optimal compensation increment according to the current operating frequency of the compressor and based on the correspondence, and perform incremental compensation for the opening of the electronic expansion valve according to the optimal compensation increment.

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