Air handling system

Abstract

This application discloses an air handling system, belonging to the field of air handling technology. The air handling system includes: a compressor; an outdoor heat exchanger; and an indoor heat exchanger, including an indoor unit heat exchanger and a fresh air heat exchanger. The indoor unit heat exchanger performs heat exchange between indoor air and refrigerant, and the fresh air heat exchanger performs heat exchange between outdoor fresh air and refrigerant. An air conditioning electronic expansion valve and the indoor unit heat exchanger are connected in series to form an indoor unit branch, and a fresh air electronic expansion valve and the fresh air heat exchanger are connected in series to form a fresh air branch. The fresh air branch and the indoor unit branch are connected in parallel. The compressor, outdoor heat exchanger, and four-way valve are located inside the outdoor unit; the indoor unit heat exchanger is located inside the indoor unit; and the fresh air heat exchanger is located inside the fresh air unit. This air handling system avoids the problems of complex system design and high cost associated with using two separate refrigeration systems.

Description

Technical Field

[0001] This application relates to the field of air handling technology, and more particularly to an air handling system. Background Technology

[0002] As people's requirements for indoor air quality increase, they are no longer satisfied with just the indoor temperature. Therefore, air conditioners and fresh air systems are being used simultaneously more and more often. Air conditioners are mainly used to regulate indoor temperature, while fresh air systems can regulate humidity while supplying fresh outdoor air into the room.

[0003] Air conditioners and fresh air systems each have their own refrigeration system, and having two refrigeration systems leads to high costs. Summary of the Invention

[0004] This application provides an air handling system that uses a single refrigeration system to control temperature and humidity, thus avoiding the problems of complex system design and high cost associated with using two refrigeration systems.

[0005] According to one aspect of this application, an air handling system includes: a compressor for compressing a refrigerant; an outdoor heat exchanger for performing heat exchange between outdoor air and the refrigerant; an indoor heat exchanger including an indoor unit heat exchanger and a fresh air heat exchanger, wherein the indoor unit heat exchanger performs heat exchange between indoor air and the refrigerant, and the fresh air heat exchanger performs heat exchange between outdoor fresh air and the refrigerant; a four-way valve for guiding the refrigerant compressed in the compressor to the outdoor heat exchanger or the indoor heat exchanger, depending on whether the air handling system is in cooling mode or heating mode; an air conditioning electronic expansion valve connected in series between the outdoor heat exchanger and the indoor unit heat exchanger; a fresh air electronic expansion valve connected in series between the outdoor heat exchanger and the fresh air heat exchanger; the air conditioning electronic expansion valve and the indoor unit heat exchanger are connected in series to form an indoor unit branch, and the fresh air electronic expansion valve and the fresh air heat exchanger are connected in series to form a fresh air branch, wherein the fresh air branch and the indoor unit branch are connected in parallel;

[0006] The compressor, outdoor heat exchanger, and four-way valve are located inside the outdoor unit; the indoor heat exchanger is located inside the indoor unit; the fresh air heat exchanger is located inside the fresh air unit; the air conditioning electronic expansion valve and the fresh air electronic expansion valve are located inside the outdoor unit; or, the air conditioning electronic expansion valve is located inside the indoor unit, and the fresh air electronic expansion valve is located inside the fresh air unit.

[0007] In some embodiments, the system further includes a controller configured to: calculate the required evaporation pressure of the indoor unit based on the temperature of the indoor unit heat exchanger; calculate the required temperature of the fresh air heat exchanger based on the dew point temperature of the fresh air; obtain the required evaporation pressure of the fresh air blower based on the required temperature of the fresh air heat exchanger; and control the frequency of the compressor based on the required evaporation pressure of the indoor unit and the required evaporation pressure of the fresh air blower.

[0008] In some embodiments, the target evaporation pressure is calculated based on the evaporation pressure required by the indoor unit and the evaporation pressure required by the fresh air unit; the compressor frequency is then controlled based on the target evaporation pressure.

[0009] Wherein, the target evaporation pressure P0 = sensible heat ratio * evaporation pressure required by the indoor unit + (1 - sensible heat ratio) * evaporation pressure required by the fresh air unit.

[0010] In some embodiments, the controller is configured to: control the opening degree of the air conditioning electronic expansion valve to be: [(required evaporation pressure of the indoor unit - target evaporation pressure) / target evaporation pressure] * initial opening degree;

[0011] The opening degree of the electronic expansion valve for fresh air is controlled as: [(target evaporation pressure - required evaporation pressure of the fresh air unit) / target evaporation pressure] * initial opening degree.

[0012] In some embodiments, the indoor unit has multiple units; the indoor unit includes: an indoor unit electronic expansion valve, which is connected in series in the indoor unit branch and connected between the indoor unit heat exchanger and the air conditioning electronic expansion valve;

[0013] The controller is used for: Sensible heat control steps: Determine whether the difference between the current evaporation pressure of the indoor unit and the required evaporation pressure of the indoor unit is less than the lower limit of the preset range. If so, reduce the opening of the electronic expansion valve of the indoor unit; Determine whether the difference between the current evaporation pressure of the indoor unit and the required evaporation pressure of the indoor unit is greater than the upper limit of the preset range. If so, increase the opening of the electronic expansion valve of the indoor unit.

[0014] In some embodiments, the fresh air unit includes: a fresh air flow valve connected in series in the fresh air branch line for regulating the refrigerant flow rate in the fresh air branch line;

[0015] The controller is used for: latent heat control steps: determining whether the difference between the current evaporation pressure of the fresh air unit and the required evaporation pressure of the fresh air unit is less than the lower limit of the preset range; if so, reducing the opening of the fresh air flow valve.

[0016] Determine whether the difference between the current evaporation pressure of the fresh air unit and the required evaporation pressure of the fresh air unit is greater than the upper limit of the preset range. If so, increase the opening of the fresh air flow valve.

[0017] In some embodiments, a controller is also included for: sensible heat control step: determining whether the temperature of the indoor unit heat exchanger is not less than the sum of the return air dew point temperature and the preset temperature value; if not, increasing the opening of the air conditioning electronic expansion valve.

[0018] Latent heat control steps: Determine whether the temperature of the fresh air heat exchanger is not greater than the difference between the fresh air dew point temperature and the preset temperature value. If not, the compressor frequency is increased; if so, the compressor maintains its current state.

[0019] In some embodiments, the indoor unit includes: an indoor unit flow valve connected in series in the indoor unit branch, used to regulate the refrigerant flow in the indoor unit branch;

[0020] The fresh air unit includes: a fresh air flow valve, connected in series in the fresh air branch, used to regulate the refrigerant flow in the fresh air branch;

[0021] The controller is also used in the following steps: In the sensible heat control step, if the temperature of the indoor unit heat exchanger is not less than the sum of the return air dew point temperature and the preset temperature value, then determine whether the indoor temperature is not greater than the difference between the set temperature and the preset temperature value; if so, then reduce the opening of the indoor unit flow valve; if not, then increase the opening of the indoor unit flow valve.

[0022] In the latent heat control step, it is determined whether the indoor humidity is not greater than the difference between the set humidity and the preset humidity value. If so, the opening of the fresh air flow valve is reduced; if not, the opening of the fresh air flow valve is increased.

[0023] In some embodiments, the controller is configured to: determine whether the indoor temperature is not greater than the difference between the set temperature and the preset temperature value, and whether the indoor humidity is not greater than the difference between the set humidity and the preset humidity value; if not, the compressor maintains its current state; if so, the compressor shuts down.

[0024] In another aspect of this application, an air handling system includes: a compressor for compressing a refrigerant; an outdoor heat exchanger for performing heat exchange between outdoor air and the refrigerant; an indoor heat exchanger including an indoor unit heat exchanger and a fresh air heat exchanger, the indoor unit heat exchanger performing heat exchange between indoor air and the refrigerant, and the fresh air heat exchanger performing heat exchange between outdoor fresh air and the refrigerant; a four-way valve for guiding the refrigerant compressed in the compressor to the outdoor heat exchanger or the indoor heat exchanger, depending on whether the air handling system is in cooling mode or heating mode; an air conditioning electronic expansion valve connected in series between the outdoor heat exchanger and the indoor unit heat exchanger; a fresh air electronic expansion valve connected in series between the outdoor heat exchanger and the fresh air heat exchanger; a subcooling heat exchanger connected in series between the outdoor heat exchanger and the fresh air electronic expansion valve; the air conditioning electronic expansion valve and the indoor unit heat exchanger form an indoor unit branch, the fresh air electronic expansion valve, the subcooling heat exchanger, and the fresh air heat exchanger form a fresh air branch, and the fresh air branch and the indoor unit branch are connected in parallel;

[0025] The compressor, outdoor heat exchanger, and four-way valve are located inside the outdoor unit; the indoor heat exchanger is located inside the indoor unit; the fresh air heat exchanger is located inside the fresh air unit; the air conditioning electronic expansion valve, the fresh air electronic expansion valve, and the subcooling heat exchanger are located inside the outdoor unit; or, the air conditioning electronic expansion valve is located inside the indoor unit, and the fresh air electronic expansion valve and the subcooling heat exchanger are located inside the fresh air unit. Attached Figure Description

[0026] Figure 1A schematic diagram of an air handling system according to some embodiments is shown;

[0027] Figure 2 A schematic diagram of an outdoor unit of an air handling system according to some embodiments is shown;

[0028] Figure 3 A schematic diagram of an indoor unit of an air handling system according to some embodiments is shown;

[0029] Figure 4 A schematic diagram of a fresh air unit for an air handling system according to some embodiments is shown;

[0030] Figure 5 A schematic diagram of a refrigeration system for an air handling system according to some embodiments is shown;

[0031] Figure 6 The control flow of an air handling system according to some embodiments is shown. Figure 1 ;

[0032] Figure 7 The control flow of an air handling system according to some embodiments is shown. Figure 2 ;

[0033] Figure 8 A schematic diagram of an air handling system according to other embodiments is shown in an application scenario;

[0034] Figure 9 A schematic diagram of an air handling system according to some other embodiments is shown;

[0035] Figure 10 A schematic diagram of a refrigeration system according to some other embodiments of an air handling system is shown;

[0036] Figure 11 A schematic diagram of the combination of a fresh air unit and a solar energy system in an air handling system according to some other embodiments is shown;

[0037] Figure 12 A schematic diagram of a refrigeration system according to yet another embodiment of an air handling system is shown;

[0038] Figure 13 A schematic diagram of an air handling system according to some embodiments in an application scenario is shown;

[0039] Figure 14 A schematic diagram of a refrigeration system according to some embodiments of an air handling system is shown. Figure 1 ;

[0040] Figure 15 A schematic diagram of a refrigeration system according to some embodiments of an air handling system is shown. Figure 2 ;

[0041] Figure 16 A schematic diagram of a refrigeration system according to some embodiments of an air handling system is shown. Figure 3 ;

[0042] Figure 17 A schematic diagram of a refrigeration system according to some embodiments of an air handling system is shown. Figure 4 . Detailed Implementation

[0043] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0044] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0048] Reference Figure 1 The air handling system 100 of this application includes an air conditioner having an outdoor unit 110 and an indoor unit 120 and a fresh air unit 130.

[0049] The outdoor unit 110 and indoor unit 120 in the air conditioner can be a two-piece structure, or the outdoor unit 110 and indoor unit 120 can be installed as a single unit in one casing.

[0050] This application uses the outdoor unit 110 and indoor unit 120, which have a two-unit structure, as an example for description:

[0051] The outdoor unit 110 is located in the outdoor space and is used to perform heat exchange between the refrigerant and the outdoor air.

[0052] Combination Figure 1 and Figure 2 The outdoor unit 110 includes an outdoor unit housing 1101, which forms the appearance of the outdoor unit 110.

[0053] The outdoor unit 110 includes: a compressor 111 for drawing in and compressing refrigerant to a high temperature and high pressure state; a four-way valve 113 for switching the refrigerant flow path in cooling mode and heating mode; and an outdoor heat exchanger 112 for performing heat exchange between outdoor air and refrigerant. In cooling mode, the outdoor heat exchanger 112 condenses the refrigerant compressed by the compressor 111, and in heating mode, it evaporates the refrigerant depressurized by the indoor unit 120.

[0054] The outdoor unit 110 also includes an outdoor fan 114 for blowing outdoor air to the outdoor heat exchanger 112.

[0055] The outdoor unit 110 includes an electronic expansion valve 115 for reducing the pressure of the refrigerant. The electronic expansion valve 115 can be located inside the outdoor unit 110 or the indoor unit 120.

[0056] Combination Figure 1 and Figure 3 The indoor unit 120 is located in the indoor space and is used to perform heat exchange between the refrigerant and the indoor air.

[0057] The indoor unit 120 includes an indoor unit housing 1201, which forms the appearance of the indoor unit 120.

[0058] The indoor unit 120 includes an indoor unit heat exchanger 121. The indoor unit heat exchanger 121 is used to perform heat exchange between the refrigerant and the indoor air. In cooling mode, the indoor unit heat exchanger 121 evaporates low-pressure liquid refrigerant and in heating mode, it condenses high-pressure gaseous refrigerant.

[0059] The indoor unit 120 also includes an indoor fan 123 for blowing air that has exchanged heat with the refrigerant through the indoor unit heat exchanger 121 into the indoor space.

[0060] In some embodiments, the air conditioner of this application can be a multi-split system, that is, it has multiple indoor units 120, for use in shopping malls, office buildings, factories, etc. The heat exchangers 121 of the multiple indoor units 120 are connected in parallel in the refrigeration system.

[0061] Reference Figure 5 The indoor unit 120 may include an indoor unit flow valve 122, which may be connected in series in the branch where the corresponding indoor unit heat exchanger 121 is located.

[0062] The indoor unit flow valve 122 can be an electronic expansion valve or a solenoid valve. By adjusting the opening of the indoor unit flow valve 122, the refrigerant flow at the corresponding branch's indoor unit heat exchanger 121 can be controlled.

[0063] The compressor 111, four-way valve 113, outdoor heat exchanger 114, air conditioning electronic expansion valve 115, and indoor heat exchanger are connected to form a refrigeration system via refrigerant piping. It should be noted that this application omits gas-liquid separators, oil separators, etc., within the refrigeration system to simplify the description of this application.

[0064] In the refrigeration system, the discharge end of compressor 111 is connected to pipe d of four-way valve 113. Pipes e and c of four-way valve 113 are connected to outdoor heat exchanger 112 and indoor heat exchanger 121, respectively. Pipe s of four-way valve 113 is connected to the suction end of compressor 111. Outdoor heat exchanger 112, air conditioning electronic expansion valve 115, and indoor heat exchanger 121 are connected in series.

[0065] In cooling mode, the four-way valve 113 guides the refrigerant compressed by the compressor 111 to the outdoor heat exchanger 112, and in heating mode, it guides the refrigerant compressed by the compressor 111 to the indoor heat exchanger 121.

[0066] The following section describes the operating modes of an air conditioner in conjunction with its refrigeration system:

[0067] Cooling mode: The compressor 111 of the outdoor unit 110 compresses the refrigerant. The refrigerant, which is compressed to a high temperature and high pressure, continues to flow through the four-way valve 113 to the outdoor heat exchanger 112. The outdoor heat exchanger 112 condenses the refrigerant into a liquid state. The liquid refrigerant flows to the indoor unit 120 after passing through the air conditioning electronic expansion valve 115.

[0068] After the electronic expansion valves 124 of each branch indoor unit depressurize and cool the liquid refrigerant, the indoor unit heat exchanger 121 of the indoor unit 120 evaporates the depressurized and cooled liquid refrigerant into a gaseous state. The gaseous refrigerant continues to flow to the outdoor unit 110 after passing through the indoor unit flow valve 122.

[0069] The gaseous refrigerant returns to the compressor 111 via the four-way valve 113 of the outdoor unit 110.

[0070] In the above-mentioned cooling mode, the refrigerant generated in the indoor unit heat exchanger 121 exchanges heat with the indoor air, thereby cooling the indoor air.

[0071] Heating mode: The compressor 111 of the outdoor unit 110 compresses the refrigerant. The refrigerant, compressed to a high temperature and pressure, continues to flow through the four-way valve 113 to the indoor unit flow valve 122 of the indoor unit 120. Then, the indoor unit heat exchanger 121 condenses the refrigerant into a liquid state and flows to the indoor unit electronic expansion valve 124, and then to the outdoor unit 110.

[0072] The electronic expansion valve 115 of the outdoor unit 110 reduces the pressure and temperature of the liquid refrigerant, and the outdoor heat exchanger 112 evaporates the reduced-pressure and cooled liquid refrigerant into a gaseous state. The gaseous refrigerant returns to the compressor 111 via the four-way valve 113.

[0073] In the above heating mode, the refrigerant generated in the indoor unit heat exchanger 121 exchanges heat with the indoor air, thereby heating the indoor air.

[0074] The following is a brief introduction to fresh air systems:

[0075] Reference Figure 4 The Fresh Air System 130 is a device that can exhaust indoor stale air and bring outdoor air into the room.

[0076] In one embodiment of the fresh air unit 130: the fresh air unit 130 includes a fresh air unit housing 1301, a heat exchange core 131, a blower 132, and an exhaust fan 133.

[0077] The fresh air unit housing 1301 forms the general appearance of the fresh air unit, and is roughly rectangular in shape. The fresh air unit housing 1301 is provided with a fresh air inlet OA, a supply air outlet SA, a return air outlet RA, and an exhaust air outlet EA.

[0078] The heat exchange core 131 is located inside the housing and is used to realize heat exchange between indoor air and outdoor fresh air.

[0079] The fresh air duct and the exhaust air duct are formed inside the fresh air unit housing 1301, and the fresh air duct and the exhaust air duct are respectively connected to the heat exchange core 131.

[0080] The fresh air duct connects the fresh air inlet OA and the supply air outlet SA to circulate outdoor fresh air; the exhaust air duct connects the return air outlet RA and the exhaust air outlet EA to circulate indoor air.

[0081] The supply air fan 132 has its corresponding air outlet SA installed in the fresh air duct to force the flow of outdoor fresh air; the exhaust fan 133 has its corresponding exhaust outlet EA installed in the exhaust duct to force the flow of indoor air.

[0082] When the fresh air unit 130 is working, under the action of the supply fan 132 and the exhaust fan 133, the indoor air from the return air vent RA flows through the heat exchange core 131 in the exhaust air duct, and the outdoor fresh air from the fresh air vent OA flows through the heat exchange core 131 in the fresh air duct. The two streams of air exchange heat at the total heat exchange core 131. The indoor air after heat exchange is blown towards the exhaust air vent EA, and the outdoor fresh air after heat exchange is blown towards the supply air vent SA.

[0083] For example, when the fresh air system is running during the summer cooling period, the outdoor fresh air obtains cooling energy from the indoor air, causing the temperature to drop; when it is running during the winter heating period, the outdoor fresh air obtains heat from the indoor air, causing the temperature to rise.

[0084] In some applications of fresh air systems, the supply air outlet SA and return air outlet RA are connected to the indoor environment via ducts, while the exhaust air outlet EA and fresh air outlet OA are connected to the outdoor environment via ducts.

[0085] In some applications of fresh air systems, the supply air outlet SA and return air outlet RA are connected to the indoor environment via ducts, while the exhaust air outlet EA and fresh air outlet OA are connected to the outdoor environment via ducts.

[0086] The fresh air unit in this application incorporates a refrigeration system to cool, dehumidify, or heat the fresh air.

[0087] The cooling system inside the fresh air unit 130 can refer to the cooling system of an air conditioner, wherein the indoor heat exchanger in the cooling system is located on the air outlet side of the heat exchange core 131 in the fresh air duct. To facilitate the distinction between the indoor heat exchanger of the air conditioner and the indoor heat exchanger of the fresh air unit, in this application, the indoor heat exchanger inside the fresh air unit 130 is referred to as the fresh air heat exchanger 134, and the indoor heat exchanger inside the air conditioner is referred to as the indoor unit heat exchanger 121.

[0088] When used as an evaporator, the fresh air heat exchanger 134 can cool and dehumidify the fresh air; when used as a condenser, it can heat the fresh air.

[0089] In the existing technology, the air conditioner and the fresh air unit 130 each have their own refrigeration system, and having two refrigeration systems will lead to high costs.

[0090] To address this issue, the air handling system of this application uses a shared refrigeration system for the fresh air unit 130 and the air conditioner, thus avoiding the high cost associated with using two separate refrigeration systems.

[0091] In some embodiments of this application, reference is made to Figure 5The outdoor unit 110 includes a compressor 111, an outdoor heat exchanger 112, a four-way valve 113, an air conditioning electronic expansion valve 115, and a fresh air electronic expansion valve 116; the indoor unit 120 includes an indoor unit heat exchanger 121; and the fresh air unit 130 includes a fresh air heat exchanger 134.

[0092] In the refrigeration system of this application, the discharge end of the compressor 111 is connected to the d pipe of the four-way valve 113; one end of the outdoor heat exchanger 112 is connected to the e pipe of the four-way valve 113; the air conditioning electronic expansion valve 115 and the indoor unit heat exchanger 121 are connected in series to form the indoor unit branch; the fresh air electronic expansion valve 116 and the fresh air heat exchanger 134 are connected in series to form the fresh air branch.

[0093] The indoor unit branch and the fresh air branch are connected in parallel between the other end of the outdoor heat exchanger 112 and the C-pipe of the four-way valve 113. The air conditioning electronic expansion valve 115 is located between the outdoor heat exchanger 112 and the indoor unit heat exchanger 121; the fresh air electronic expansion valve 116 is located between the outdoor heat exchanger 112 and the fresh air heat exchanger 134.

[0094] In this application, by connecting the indoor unit heat exchanger 121 of the indoor unit and the fresh air heat exchanger 134 of the fresh air unit 130 in parallel between the outdoor heat exchanger 112 and the c-pipe of the four-way valve 113, and by adjusting the opening of the air conditioning electronic expansion valve 115 to regulate the evaporation pressure of the air conditioner, and by adjusting the opening of the fresh air electronic expansion valve 116 to regulate the evaporation pressure of the fresh air unit, it is possible to use one refrigeration system to simultaneously control two evaporation pressures to create two evaporation temperatures and achieve independent control of the air conditioner and the fresh air unit, thus avoiding the problems of complex system design and high cost caused by using two sets of refrigeration systems.

[0095] In some embodiments, an indoor unit flow valve 122 is connected in series on the indoor unit branch. The indoor unit flow valve 122 may be located between the indoor unit heat exchanger 121 and the c-pipe of the four-way valve 113. The indoor unit flow valve 122 can be used to regulate the refrigerant flow in the indoor unit heat exchanger 121 to ensure proper heat exchange at the indoor unit heat exchanger 121.

[0096] A fresh air flow valve 135 is connected in series on the fresh air branch. The fresh air flow valve 135 can be located between the fresh air heat exchanger 134 and the c-pipe of the four-way valve 113. The fresh air flow valve 135 can be used to regulate the refrigerant flow at the fresh air heat exchanger 134 to ensure proper heat exchange at the fresh air heat exchanger 134.

[0097] In some embodiments, the indoor unit 120 may include an indoor unit electronic expansion valve 124, which is connected in series in the branch where the corresponding indoor unit heat exchanger 121 is located. The pressure in the corresponding branch can be controlled by adjusting the opening of the indoor unit electronic expansion valve 124. The indoor unit electronic expansion valve 124 may be located between the air conditioning electronic expansion valve 115 and the indoor unit heat exchanger 121.

[0098] For example, the indoor unit has i units, i = 4, and the four indoor unit heat exchangers are labeled 121-1, 121-2, 121-3, and 121-4, respectively. Specifically, the indoor unit heat exchanger (121-1) branch corresponds to the indoor unit flow valve (122-1) and the indoor unit electronic expansion valve (124-1); the indoor unit heat exchanger (121-2) branch corresponds to the indoor unit flow valve (122-2) and the indoor unit electronic expansion valve (124-2); the indoor unit heat exchanger (121-3) branch corresponds to the indoor unit flow valve (122-3) and the indoor unit electronic expansion valve (124-3); and the indoor unit heat exchanger (121-4) branch corresponds to the indoor unit flow valve (122-4) and the indoor unit electronic expansion valve (124-4).

[0099] In some embodiments, the air handling system may include a subcooling heat exchanger 117. The subcooling heat exchanger 117 is located inside the outdoor unit 110, connected in series on the fresh air branch and situated between the outdoor heat exchanger 112 and the fresh air electronic expansion valve 116. As the refrigerant passes through the subcooling heat exchanger 117, it transfers heat to the outdoor air.

[0100] The subcooling heat exchanger 117 is designed to generate sufficient subcooling to overcome the long piping pressure drop between the outdoor unit 110 and the fresh air unit 130, thus preventing liquid refrigerant flashover caused by pipe resistance.

[0101] The following describes the cyclic process by which the refrigeration system of this application achieves temperature and humidity control in summer:

[0102] High-temperature, high-pressure refrigerant is discharged from the compressor 111 outlet, passes through the four-way valve 113 to the outdoor heat exchanger 112 (used as a condenser), where it transfers heat to the outdoor air and becomes a high-temperature, low-pressure two-phase refrigerant, which then splits into two paths:

[0103] Route 1: After passing through the air conditioning electronic expansion valve 115, the refrigerant reaches the indoor unit electronic expansion valve 124 of each branch and is throttled and depressurized into a low-temperature, low-pressure liquid refrigerant. Then it flows to the heat exchanger 121 of each indoor unit. The refrigerant flow rate of each indoor unit is determined by the opening of the indoor unit flow valve 122. At the indoor unit heat exchanger 121, it exchanges heat with the indoor air (the indoor air is cooled). The refrigerant absorbs the heat of the indoor air and becomes a low-temperature, low-pressure gaseous refrigerant.

[0104] The second route: The refrigerant flows to the subcooling heat exchanger 117 to transfer heat to the outdoor air, and then passes through the fresh air electronic expansion valve 116 to reduce its pressure and become a low-temperature, low-pressure liquid refrigerant. The throttling state is determined by the opening degree of the fresh air flow valve. Then it reaches the fresh air heat exchanger 134. Since the fresh air needs to be dehumidified, the evaporation temperature of this route needs to be controlled by the required dew point temperature. The refrigerant in this route exchanges heat with the fresh air, absorbing the heat of the fresh air and becoming a low-temperature, low-pressure gaseous refrigerant.

[0105] The two refrigerants then mix and flow to the four-way valve 113, finally returning to the compressor 111.

[0106] The following will describe the signal flow between the components contained in the air handling system.

[0107] The controller is used to receive the detection data of the air conditioner and the fresh air unit 130, perform calculations, and then control the operation of the air conditioner and the fresh air unit 130.

[0108] The memory is used to store programs and data related to the operation of the air handling system; the memory may be implemented by at least one of, but is not limited to, non-volatile memory (e.g., cache, read-only memory (ROM), programmable ROM (PROM), erasable programmable ROM (EPROM) and flash memory), volatile memory (e.g., random access memory (RAM)) or storage media such as hard disk drive (HDD) and CD-ROM.

[0109] The communication module is used to enable communication between the controller and the air conditioner, and between the controller and the fresh air unit 130; for example, the temperature and humidity detection information of the air conditioner and the fresh air unit 130 can be shared with the controller through the communication module.

[0110] The communication module can be either wired or wireless. Wireless communication can use at least one of the following as cellular communication protocols: 5G, LTE, LTE-A, CDMA, WCDMA, UMTS, Wi-Fi, or GSM. Additionally, wireless communication can include local communication, which may include at least one of Wi-Fi, Bluetooth, or NFC. Wired communication can include at least one of Universal Serial Bus (USB), HDMI, RS-132, or POTS.

[0111] The input unit can receive input from the user and may include push-button switches, membrane switches, or touch panels for receiving operating commands for the air handling system. Specifically, the input unit can receive indoor temperature and humidity settings from the user.

[0112] The return air temperature and humidity sensor can be installed at the air inlet of the indoor unit to detect the temperature and humidity of the return air.

[0113] An outlet temperature sensor can be installed at the outlet of the indoor unit heat exchanger 121 to detect the temperature at the outlet of the indoor unit heat exchanger 121.

[0114] An indoor unit heat exchanger temperature sensor can be installed on the indoor unit heat exchanger 121 to detect the temperature of the indoor unit heat exchanger 121.

[0115] A pressure sensor can be installed at the inlet of the indoor unit heat exchanger 121 to detect pressure.

[0116] A fresh air temperature and humidity sensor can be installed on the windward side of the fresh air heat exchanger 134, that is, in the fresh air duct between the fresh air heat exchanger 134 and the heat exchange core 131, to detect the temperature and humidity of the fresh air on the windward side of the fresh air heat exchanger 134.

[0117] A temperature sensor for the fresh air heat exchanger can be installed on the fresh air heat exchanger 134 to detect the temperature of the fresh air heat exchanger 134.

[0118] The air handling system of this application can achieve independent temperature and humidity control, that is, the indoor unit controls the temperature and the fresh air unit controls the humidity.

[0119] The following section will describe method one for independent temperature and humidity control in an air handling system, referring to... Figure 6 :

[0120] S1. Calculate the required evaporation pressure P1 for the indoor unit and the required evaporation pressure P2 for the fresh air unit.

[0121] In the above steps, the required evaporation pressure P1 of the indoor unit is calculated from the temperature Tfz of the indoor unit's heat exchanger.

[0122] Specifically, the temperature Tfz of the indoor unit's heat exchanger can be obtained from the temperature sensor's reading. If the indoor unit is a multi-split system, then Tfz is the average temperature of all indoor unit heat exchangers. Adding a preset correction value YO to the indoor unit's heat exchanger temperature Tfz allows for the estimation of the refrigerant temperature Tfz+YO within the heat exchanger. The required evaporation pressure P1 of the indoor unit can then be obtained from the refrigerant temperature and pressure correspondence table.

[0123] In the above steps, the required evaporation temperature P2 of the fresh air unit can be calculated from the required temperature of the fresh air heat exchanger.

[0124] Specifically, the temperature and relative humidity of the fresh air can be obtained from the fresh air temperature and humidity sensor on the windward side of the fresh air heat exchanger, and the dew point temperature TLoa of the fresh air can be calculated based on the fresh air temperature and relative humidity.

[0125] Since the fresh air heat exchanger is mainly used for dehumidification, the temperature at the fresh air heat exchanger needs to be lower than the dew point temperature to ensure that water in the fresh air is separated out. Therefore, the required temperature Ts2 of the fresh air heat exchanger is lower than (TLoa-A), where A represents the preset capacity value, for example, A=2. For example, Ts2 can be calculated according to TLoa-A.

[0126] The required evaporation pressure P2 of the fresh air unit can be calculated based on the required temperature Ts2 of the fresh air heat exchanger. For specific calculation methods, please refer to the calculation method from Tfz to P1, which will not be repeated here.

[0127] S2. Control the compressor frequency according to the evaporation pressure P1 required by the indoor unit and the evaporation pressure P2 required by the fresh air unit.

[0128] The specific steps of S2 are as follows: calculate the target evaporation pressure P0 based on the required evaporation pressure P1 of the indoor unit and the evaporation pressure P2 of the fresh air unit; adjust the compressor frequency according to the target evaporation pressure P0.

[0129] Wherein, the target evaporation pressure P0 = α * evaporation pressure required by the indoor unit P1 + (1-α) * evaporation pressure required by the fresh air unit P2. α represents the sensible heat ratio.

[0130] The sensible heat ratio α is the proportion of sensible heat load to the total load. Sensible heat load = indoor load + fresh air sensible heat load; where, indoor load = room area * load index; fresh air sensible heat load = fresh air volume * density * (Tαa - Tset), where Tαa - Tset represents the difference between the fresh air temperature and the indoor set temperature.

[0131] Latent heat load = Fresh air volume * Density * (doa - dset), where doa - dset represents the difference in humidity between the fresh air and the set indoor humidity. Total load = Sensible heat load + Latent heat load.

[0132] In this application, the target evaporation pressure P0 is calculated based on the sensible heat ratio α, the required indoor evaporation pressure P1, and the required evaporation pressure P2 of the fresh air unit. That is, the target evaporation pressure P0 is calculated according to the weight of sensible heat load and latent heat load, which makes the calculation of the target evaporation pressure more accurate and reasonable.

[0133] In the above steps, the target frequency of the compressor is obtained based on the target evaporation pressure P0, which is applicable to the calculation method of existing technology, and will not be repeated here.

[0134] S3. Adjust the opening of the air conditioner electronic expansion valve according to the difference between the required evaporation pressure P1 and the target evaporation pressure P0 of the indoor unit; adjust the opening of the fresh air electronic expansion valve according to the difference between the required evaporation pressure P2 and the target evaporation pressure P0 of the fresh air unit.

[0135] The opening degree of the air conditioner electronic expansion valve = [(required evaporation pressure P1 of indoor unit - target evaporation pressure P0) / target evaporation pressure P0] * initial opening degree.

[0136] The opening degree of the fresh air electronic expansion valve = [(target evaporation pressure P0 - required evaporation pressure P2 of the fresh air unit) / target evaporation pressure P0] * initial opening degree.

[0137] S4. Sensible heat control steps: Determine whether the difference between the current evaporation pressure P1i of the indoor unit and the required evaporation pressure P1 of the indoor unit is within the preset range. If yes, maintain the current state; if no, and P1i-P1 is less than the lower limit of the preset range, reduce the opening of the indoor unit's electronic expansion valve; if no, and P1i-P1 is greater than the upper limit of the preset range, increase the opening of the indoor unit's electronic expansion valve.

[0138] The current evaporation pressure P1i of the indoor unit can be detected by the pressure sensor at the inlet of the indoor unit's heat exchanger.

[0139] For example, when -0.1≤P1i-P1≤0.1, it means that P1i-P1 is within the preset range, and the current evaporation pressure of the indoor unit is close to or equal to the required evaporation pressure. At this time, it is not necessary to adjust the opening of the electronic expansion valve of the indoor unit.

[0140] When P1i-P1<-0.1, it indicates that the current evaporation pressure P1i of the indoor unit is relatively low. The opening of the electronic expansion valve of the indoor unit can be reduced to increase the pressure P1i.

[0141] When P1i-P1>0.1, it indicates that the current evaporation pressure P1i of the indoor unit is relatively high. The opening of the electronic expansion valve of the indoor unit can be increased to reduce the pressure P1i.

[0142] After increasing or decreasing the opening of the indoor unit's electronic expansion valve, the system periodically returns to determine whether the difference between the current evaporation pressure P1i of the indoor unit and the required evaporation pressure P1 of the indoor unit is within the preset range, until P1i-P1 is within the preset range.

[0143] In some embodiments, the sensible heat control step further includes controlling the opening degree of the indoor unit flow valve 122 according to the temperature of the refrigerant and the temperature of the indoor unit heat exchanger outlet.

[0144] The opening degree of the indoor unit flow valve is EVI(122-i)=E*(TLi-TBLi)+F*(G(122-i) / ∑G(122-i).

[0145] Where E and F are constants; TLi is the temperature value at the outlet of each indoor unit heat exchanger; TBLi is the saturation temperature corresponding to the evaporation pressure P1; G(122-i) is the capacity of each indoor unit heat exchanger; and ∑G(122-i) is the sum of the capacities of all indoor unit heat exchangers.

[0146] S5. Latent heat control steps: Determine whether the difference between the current evaporation pressure P2i of the fresh air unit and the required evaporation pressure P2 of the fresh air unit is within the preset range. If yes, maintain the current state; if no, and P2i-P2 is less than the lower limit of the preset range, reduce the opening of the fresh air flow valve; if no, and P1i-P1 is greater than the upper limit of the preset range, increase the opening of the indoor unit's fresh air flow valve.

[0147] The current evaporation pressure P2i of the fresh air unit can be detected by the pressure sensor at the inlet of the fresh air heat exchanger.

[0148] In steps S4 and S5, sensible heat control is performed by the indoor unit, while latent heat control is performed by the fresh air unit. After step S4 or S5, proceed to step S6.

[0149] S6. Determine whether the indoor temperature Tin is not greater than the difference between the indoor set temperature Tset and the preset temperature value, and whether the indoor humidity din is not greater than the difference between the indoor set humidity dset and the preset humidity value. If yes, the compressor will stop; if no, the compressor will maintain its current state.

[0150] For example, if the conditions Tin≤Tset-1 and din≤dset-0.5 are met, it means that the indoor temperature and humidity are within the preset range; if Tin≤Tset-1 is not met, it means that the indoor temperature is not within the preset range; if din≤dset-0.5 is not met, it means that the indoor humidity is not within the preset range.

[0151] In this step, if the indoor temperature and humidity Tin is close to or equal to the indoor set temperature and humidity Tset, it means that the indoor temperature and humidity Tin is suitable. At this time, the compressor can be controlled to stop to save energy. If the indoor temperature Tin differs greatly from the set temperature Tset, or the indoor humidity din differs greatly from the set humidity dset, it means that temperature and humidity control needs to continue. At this time, the compressor continues to work.

[0152] The following section will describe method two for independent temperature and humidity control in air handling systems, referring to... Figure 7 :

[0153] Sensible heat control:

[0154] S11. Determine whether the temperature Tfz of the indoor unit heat exchanger is not less than the sum of the return air dew point temperature TLin and the preset temperature value. If not, increase the opening of the air conditioner electronic expansion valve; if yes, proceed to S12.

[0155] In step S11, the return air temperature and relative humidity can be detected by the temperature and humidity sensor at the return air vent of the indoor unit, and the return air dew point temperature TLin can be calculated based on the return air temperature and relative humidity.

[0156] For example, the preset temperature value is 1. When the temperature Tfz of the indoor unit heat exchanger is greater than TLin+1, it means that the temperature of the indoor unit heat exchanger is greater than the dew point temperature. When the return air passes through the indoor unit heat exchanger, no condensate will be generated, thus achieving the purpose of the indoor unit only controlling the temperature.

[0157] If the indoor unit heat exchanger temperature Tfz≥TLin+1 does not hold true, it means that the indoor unit heat exchanger temperature is lower than the return air dew point temperature. When the return air passes through the indoor unit heat exchanger, condensate may be released. In order to avoid the indoor unit handling latent heat, the opening of the air conditioner electronic expansion valve can be increased, thereby raising the temperature at the indoor unit heat exchanger.

[0158] After increasing the opening of the air conditioner's electronic expansion valve, return to continue judging whether the indoor unit's heat exchanger temperature Tfz ≥ TLin + 1 is true, until the judgment is true.

[0159] S12. Determine whether the indoor temperature Tin is not greater than the difference between the indoor set temperature Tset and the preset temperature value. If so, reduce the opening of the indoor unit flow valve to reduce the refrigerant flow; if not, increase the opening of the indoor unit flow valve.

[0160] Latent heat control:

[0161] S13. Determine whether the temperature Tz of the fresh air heat exchanger is not less than the difference between the fresh air dew point temperature TLoa and the preset temperature value. If not, the compressor frequency is increased; if so, the compressor maintains its current state.

[0162] For example, when Tz ≤ TLoa-1, it indicates that the difference between the temperature of the fresh air heat exchanger and the fresh air dew point temperature is within a preset range. Under this condition, the temperature of the fresh air heat exchanger is lower than the fresh air dew point temperature, which ensures the dehumidification effect at the fresh air heat exchanger.

[0163] If this condition is not met, it means that the temperature of the fresh air heat exchanger is not lower than the fresh air dew point temperature, and the purpose of dehumidifying the fresh air cannot be achieved. The compressor needs to be frequency-increased to reduce the temperature at the fresh air heat exchanger.

[0164] After the compressor frequency is increased, the system periodically returns to check whether the temperature Tz of the fresh air heat exchanger is not less than the difference between the fresh air dew point temperature TLoa and the preset temperature value, until the condition is met.

[0165] S14. Determine whether the indoor humidity din is not greater than the difference between the set humidity dset and the preset humidity value. If yes, reduce the opening of the fresh air flow valve; if no, increase the opening of the fresh air flow valve.

[0166] For example, when the indoor humidity din≤dset-0.5 is true, it means that the indoor humidity is suitable. At this time, the opening of the fresh air flow valve can be reduced. If it is not true, it means that the indoor humidity is too high. The opening of the fresh air flow valve can be increased to improve the dehumidification efficiency.

[0167] After reducing the opening of the fresh air flow valve, the system periodically returns to check whether the indoor humidity din is not greater than the difference between the set humidity dset and the preset humidity value, until the condition is met.

[0168] After step S12 or step S14, proceed to S15.

[0169] S15. Determine whether the indoor temperature Tin is not greater than the difference between the indoor set temperature Tset and the preset temperature value, and whether the indoor humidity din is not greater than the difference between the indoor set humidity dset and the preset humidity value. If yes, the compressor will stop; if no, the compressor will maintain its current state.

[0170] For example, if the conditions Tin≤Tset-1 and din≤dset-0.5 are met, it means that the indoor temperature and humidity are within the preset range; if Tin≤Tset-1 is not met, it means that the indoor temperature is not within the preset range; if din≤dset-0.5 is not met, it means that the indoor humidity is not within the preset range.

[0171] In this step, if the indoor temperature and humidity are close to or equal to the set indoor temperature and humidity, it means that the indoor temperature and humidity are suitable. At this time, the compressor can be controlled to stop to save energy. If the indoor temperature differs greatly from the set temperature, or the indoor humidity differs greatly from the set humidity, it means that temperature and humidity control needs to continue. At this time, the compressor continues to work.

[0172] In this application, by connecting the indoor unit heat exchanger 121 of the indoor unit and the fresh air heat exchanger 134 of the fresh air unit 130 in parallel between the outdoor heat exchanger 112 and the c-pipe of the four-way valve 113, and by adjusting the opening of the air conditioning electronic expansion valve 115 to regulate the evaporation pressure of the air conditioner, and by adjusting the opening of the fresh air electronic expansion valve 116 to regulate the evaporation pressure of the fresh air unit, it is possible to use one refrigeration system to simultaneously control two evaporation pressures to create two evaporation temperatures and achieve independent control of the air conditioner and the fresh air unit, thus avoiding the problems of complex system design and high cost caused by using two sets of refrigeration systems.

[0173] In this application, by controlling the evaporation pressure of the indoor unit and the evaporation pressure of the fresh air unit, the temperature and humidity of the indoor unit handling sensible heat and the fresh air unit handling sensible heat are independently controlled, thus avoiding the problem of high energy consumption when the indoor unit handles latent heat.

[0174] In this application, the target evaporation pressure is calculated based on the sensible heat ratio, the required indoor evaporation pressure P1, and the required evaporation pressure P2 of the fresh air unit. That is, the target evaporation pressure is calculated according to the weight of the sensible heat load and the sensible heat load, which makes the calculation of the target evaporation pressure more accurate and reasonable.

[0175] In this application, for multi-split air conditioners, an indoor unit electronic expansion valve is installed on the indoor unit branch line, and the evaporation pressure of a single indoor unit is adjusted by controlling the indoor unit electronic expansion valve.

[0176] In this application, by adjusting the opening of the air conditioner's electronic expansion valve, the temperature of the indoor unit's heat exchanger is controlled to be higher than the return air dew point temperature, so that the indoor unit only processes sensible heat. By controlling the compressor frequency, the temperature of the fresh air heat exchanger in the fresh air unit is controlled to be lower than the fresh air dew point temperature, so that the fresh air unit processes latent heat, thus achieving independent control of temperature and humidity.

[0177] In some embodiments of this application, reference is made to Figure 8 , Figure 9 The fresh air unit 130 may include a fresh air-side heat exchanger 1371. The fresh air-side heat exchanger 1371 is located inside the fresh air duct. When the fresh air-side heat exchanger 1371 is used as an evaporator, it cools the fresh air; when the fresh air-side heat exchanger 1371 is used as a condenser, it heats the fresh air.

[0178] In some embodiments, the fresh air unit 130 may include an exhaust-side heat exchanger 1372. The exhaust-side heat exchanger 1372 is disposed within the exhaust duct. When the exhaust-side heat exchanger 1372 functions as a condenser, it heats the indoor exhaust air; when it functions as an evaporator, it cools the indoor exhaust air.

[0179] In some embodiments, the fresh air unit 130 may include an adsorption wheel 138. The adsorption wheel 138 is rotatably connected within the fresh air unit housing 1301. A portion of the adsorption wheel 138 is located within the exhaust duct and on the air outlet side of the exhaust-side heat exchanger 1372, while another portion of the adsorption wheel 138 is located within the fresh air duct and on the air outlet side of the fresh air-side heat exchanger 1371.

[0180] When low-temperature air passes through the adsorption wheel 138, moisture can be absorbed by the adsorption wheel 138. When high-temperature air passes through the adsorption wheel 138, moisture can be carried away, thus regenerating the adsorption wheel 138.

[0181] In some embodiments, refer to Figure 9 and Figure 10 In the refrigeration system of the air handling system, the exhaust port of the compressor 111 is connected to the d-tube of the four-way valve 113, and the s-tube of the four-way valve 113 is connected to the suction port of the compressor 11.

[0182] The e-pipe of the four-way valve 113 is connected to one end of the outdoor heat exchanger 112. The c-pipe of the four-way valve 113 is connected to one end of the indoor unit heat exchanger 121 and one end of the fresh air side heat exchanger 1371.

[0183] The four-way valve 113 can selectively guide the refrigerant compressed by the compressor to the outdoor heat exchanger 112, or to the indoor unit heat exchanger 121 and the fresh air side heat exchanger 1371. Specifically, in cooling mode, the refrigerant compressed by the compressor 111 flows to the outdoor heat exchanger 112 through the four-way valve 113; in heating mode, the refrigerant compressed by the compressor 111 flows to the indoor unit heat exchanger 121 and the fresh air side heat exchanger 1371 through the four-way valve 113.

[0184] The other end of the outdoor heat exchanger 112 and the c-pipe of the four-way valve 113 are connected in parallel with a first branch and a second branch.

[0185] The air conditioner electronic expansion valve 115 and the indoor unit heat exchanger 121 are connected in series on the first branch, and the air conditioner electronic expansion valve 115 is located between the outdoor heat exchanger 112 and the indoor unit heat exchanger 121.

[0186] The exhaust-side heat exchanger 1372, the seventh electronic expansion valve 1392, and the fresh air-side heat exchanger 1371 are connected in series on the second branch, and the exhaust-side heat exchanger 1372 is located between the outdoor heat exchanger 112 and the seventh electronic expansion valve 1392.

[0187] In cooling mode, the refrigerant flow direction of the refrigeration system is as follows:

[0188] High-temperature, high-pressure refrigerant is discharged from the compressor 111 outlet, passes through the four-way valve 113 to the outdoor heat exchanger 112, where it transfers heat to the outdoor air and becomes a high-temperature, low-pressure two-phase refrigerant, which then splits into two paths:

[0189] Route 1: The refrigerant flows to the exhaust side heat exchanger 1372, where it exchanges heat with the exhaust air and its temperature continues to drop. Then, it passes through the seventh electronic expansion valve 1392, where it is throttled and depressurized to become a low-temperature, low-pressure liquid refrigerant. This liquid refrigerant then flows into the fresh air side heat exchanger 1371, where it exchanges heat with the fresh air and absorbs its heat to become a high-temperature, low-pressure gaseous refrigerant. This gas then flows to the indoor unit's gas pipe, where it merges with the refrigerant at the indoor unit's outlet and flows back to the four-way valve 113, finally returning to the compressor.

[0190] Route 2: After passing through the air conditioner electronic expansion valve 115, the refrigerant is reduced in pressure and becomes a low-temperature, low-pressure liquid refrigerant. Then it reaches the indoor unit heat exchanger 121, where it exchanges heat with the indoor air, absorbs the heat from the indoor air, and becomes a high-temperature, low-pressure gaseous refrigerant. It then merges with the refrigerant of the fresh air unit, flows back to the four-way valve 113, and finally returns to the compressor.

[0191] Airflow path inside the 130 fresh air unit:

[0192] Fresh air: When it passes through the hot return air core 131, it exchanges heat with the indoor exhaust air and its temperature decreases. When it continues to pass through the fresh air side heat exchanger 1371 (used as an evaporator), it is cooled and dehumidified. When it continues to pass through the adsorption wheel 138, it is dehumidified and heated before being sent into the room.

[0193] Exhaust air: When passing through the hot return air core 131, it exchanges heat with the outdoor fresh air and the temperature rises. When it continues to pass through the exhaust side heat exchanger 134 (used as a condenser), it is heated and the temperature rises. When it continues to pass through the adsorption wheel 138, it carries away the moisture of the adsorption wheel 138 and finally exhausts to the outside.

[0194] In the embodiments of this application, by connecting the indoor unit heat exchanger 121 of the indoor unit 120, the exhaust side heat exchanger 1372 and the fresh air side heat exchanger 1371 in the fresh air unit 130 in parallel within the refrigeration system, the air conditioner and the fresh air unit can share a single refrigeration system, thereby reducing costs.

[0195] In some embodiments, the refrigeration system includes a subcooling heat exchanger 117 connected in series in the first branch and located between the outdoor heat exchanger 112 and the air conditioning electronic expansion valve 115. The subcooling heat exchanger 117 is used to exchange heat with outdoor air.

[0196] When the outdoor unit 110 is far from the indoor unit 120, the pipes are long, and the pipe resistance may cause the liquid refrigerant flowing from the outdoor heat exchanger 114 to flash. The subcooling heat exchanger 117 can prevent refrigerant flashing.

[0197] In some embodiments, the indoor unit 120 has a plurality of indoor unit heat exchangers 121 within the plurality of indoor units 120, which are arranged in parallel in the refrigeration system.

[0198] A flow valve is connected in series on each branch where the indoor unit heat exchanger 121 is located. The flow valve can be installed inside the indoor unit 120 to regulate the refrigerant flow of that branch.

[0199] The flow valve can be a solenoid valve or an electronic expansion valve. This application uses the eighth electronic expansion valve as an example to illustrate the flow valve.

[0200] For example, there are i indoor units 120. When i=3, the eighth electronic expansion valves in the three indoor units 120 are respectively labeled as the eighth electronic expansion valve (126-1), the eighth electronic expansion valve (126-2), and the eighth electronic expansion valve (126-3).

[0201] In some embodiments, the refrigeration system may include a fresh air flow valve connected in series with the fresh air side heat exchanger 1371 to regulate the refrigerant flow at the fresh air side heat exchanger 1371.

[0202] The fresh air flow valve can be installed inside the fresh air unit 130 or on the refrigerant pipeline outside the machine.

[0203] The fresh air flow valve can be a solenoid valve or an electronic expansion valve. This application uses the ninth electronic expansion valve 1391 as an example to illustrate the fresh air flow valve.

[0204] In some embodiments, refer to Figure 11 The fresh air unit 130 can be combined with the solar energy system 140.

[0205] The solar energy system 140 includes a collector 141 for receiving solar energy to heat the water inside it. A water supply pipe is connected to the collector 141, and the other end of the water supply pipe is connected to a water source for supplying water to the collector 141.

[0206] The solar energy system 140 includes a water heat exchanger 142 through which water flows. When air flows through the water heat exchanger 142, the water heat exchanger 142 performs heat exchange between the water and the air.

[0207] The solar collector 141 and the water heat exchanger 142 are connected by water pipes to form a water circulation system.

[0208] The water heat exchanger 142 can be installed in the exhaust duct of the fresh air unit 130 and located on the windward side of the adsorption rotor 138.

[0209] When the collector 141 circulates hot water to the water heat exchanger 142, the water heat exchanger 142 can heat the exhaust air in the fresh air unit 130. When the high-temperature exhaust air continues to pass through the adsorption rotor 138, it is beneficial to the regeneration of the adsorption rotor 138.

[0210] The embodiments provided in this application improve regeneration efficiency by integrating the water heat exchanger 142 of the solar system 140 into the fresh air unit 130, using the water heat exchanger 142 as the regeneration heat source for the adsorption rotor 138.

[0211] In some embodiments, the water heat exchanger 142 can replace the exhaust-side heat exchanger 1372. That is, when the solar energy system 140 is working, the exhaust-side heat exchanger 1372 may not be used, and solar energy can replace part of the energy of the refrigeration system, which can achieve the effect of energy saving.

[0212] Reference Figure 12 The refrigeration system may include a first switching valve, connected in series on the second branch and located between the outdoor heat exchanger 112 and the exhaust-side heat exchanger 1372, for controlling the on / off of refrigerant at the exhaust-side heat exchanger 1372. The first switching valve may be a solenoid valve or an electronic expansion valve.

[0213] Taking the first switching valve as the first solenoid valve 1191 as an example: When the first solenoid valve 1191 is open, the outdoor heat exchanger 112 is connected to the exhaust side heat exchanger 1372, and the refrigerant can flow into the exhaust side heat exchanger 1372; when the first solenoid valve 1191 is closed, the outdoor heat exchanger 112 is not connected to the exhaust side heat exchanger 1372, and the exhaust side heat exchanger 1372 does not function.

[0214] The refrigeration system may include a second switching valve, one end of which is connected between the air conditioning electronic expansion valve 115 and the indoor unit heat exchanger 121, and the other end of which is connected between the seventh electronic expansion valve 1392 and the fresh air side heat exchanger 1371. The second switching valve may be a solenoid valve or an electronic expansion valve.

[0215] Taking the second switching valve, the second solenoid valve 1192, as an example: When the first solenoid valve 1191 is open and the second solenoid valve 1192 is open, the exhaust side heat exchanger 1372 is disconnected, and the fresh air side heat exchanger 1371 is connected in parallel with the indoor unit heat exchanger 121, with refrigerant flowing through the fresh air side heat exchanger 1371; when the first solenoid valve 1191 is open and the second solenoid valve 1192 is open, the first branch and the second branch are connected in parallel.

[0216] Therefore, by varying the on / off states of the first solenoid valve 1191 and the second solenoid valve 1192, three operating modes can be achieved.

[0217] The first method, a dehumidification cycle that does not use solar energy, involves opening the first solenoid valve 1191 and disengaging the second solenoid valve 1192:

[0218] High-temperature, high-pressure refrigerant is discharged from the compressor 111 outlet, passes through the four-way valve 112 to the outdoor heat exchanger 112, where it transfers heat to the outdoor air and becomes a high-temperature, low-pressure two-phase refrigerant, which then splits into two paths:

[0219] Route 1: After passing through the first solenoid valve 1191, the refrigerant flows to the exhaust side heat exchanger 1372. After exchanging heat with the exhaust air, the refrigerant temperature continues to drop. Then, after passing through the seventh electronic expansion valve 1392, the refrigerant is throttled and depressurized into a low-temperature, low-pressure liquid refrigerant. It then flows into the fresh air side heat exchanger 1371, where it exchanges heat with the fresh air and absorbs the heat from the fresh air to become a high-temperature, low-pressure gaseous refrigerant. It then flows to the gas pipe of the indoor unit, merges with the refrigerant at the indoor unit outlet, and flows back to the four-way valve 113, finally returning to the compressor.

[0220] Route 2: The refrigerant flows to the subcooling heat exchanger 117, where it continues to exchange heat with the outdoor air and transfers the heat to the outdoor air. Then, it passes through the air conditioning electronic expansion valve 115, where it is throttled and depressurized to become a low-temperature, low-pressure liquid refrigerant. It then flows to the heat exchanger 121 of each indoor unit, where it exchanges heat with the indoor air and absorbs the heat from the indoor air to become a high-temperature, low-pressure gaseous refrigerant. It then flows to the eighth electronic expansion valve (126-1), (123-2), and (123-3) of each indoor unit. The refrigerant from all indoor unit outlets merges with the refrigerant from the fresh air unit and flows back to the four-way valve 113, finally returning to the compressor.

[0221] The second method uses solar-powered dehumidification circulation instead of condensing heat. In this method, the first solenoid valve 1191 is disconnected, and the second solenoid valve 1192 is opened.

[0222] High-temperature and high-pressure refrigerant is discharged from the compressor 111 exhaust port, passes through the four-way valve 113 to reach the outdoor heat exchanger 112, where it transfers heat to the outdoor air and becomes a high-temperature and low-pressure two-phase refrigerant. It then flows to the subcooling heat exchanger 117 to continue exchanging heat with the outdoor air and transferring heat to the outdoor air. After passing through the air conditioning electronic expansion valve 115 for throttling and pressure reduction, it becomes a low-temperature and low-pressure liquid refrigerant, which then reaches the indoor unit heat exchanger 121 and the fresh air side heat exchanger 1371 to process indoor air and fresh air.

[0223] On the indoor unit side: The refrigerant passes through the heat exchanger 121 of each indoor unit, exchanges heat with the indoor air, absorbs the heat of the indoor air and becomes a high-temperature, low-pressure gaseous refrigerant, and then flows to the eighth electronic expansion valve (126-1), (123-2), and (123-3) of each indoor unit. The refrigerant at the outlet of all indoor units merges with the refrigerant of the fresh air unit, flows back to the four-way valve 113, and finally returns to the compressor.

[0224] On the fresh air unit side: the refrigerant flows from the second solenoid valve 1192 to the fresh air side heat exchanger 1371, where it exchanges heat with the fresh air and absorbs the heat of the fresh air to become a high-temperature, low-pressure gaseous refrigerant. It then flows to the ninth electronic expansion valve 1391, where it merges with the refrigerant at the indoor unit outlet and flows back to the four-way valve 113, and finally back to the compressor.

[0225] At this time, the solar energy system is working. The hot water at water heat exchanger 142 heats the exhaust air, and then the temperature drops before returning to the collector to complete one cycle of heating.

[0226] The third method utilizes both solar energy and condensation heat: when the solar energy system is activated, the first solenoid valve 1191 opens, and the second solenoid valve 1192 closes. When solar energy and condensation heat are used simultaneously, the regeneration efficiency of the adsorption rotor 138 is higher.

[0227] According to the embodiments of this application, continue to refer to Figure 11The solar system 140 includes a water pump 145 for pumping water so that the water flows through the solar system.

[0228] The water pipe includes a water supply pipe 143, which is connected between the outlet of the solar collector 141 and the inlet of the water heat exchanger 142.

[0229] The water pipe includes a return water pipe 144, which is connected between the outlet of the water heat exchanger 143 and the inlet of the collector 141.

[0230] The water pump 145 can be connected to the water supply pipe 143. Driven by the water pump 145, the hot water in the collector 141 flows into the water heat exchanger 142 along the water supply pipe 143, and then continues to flow back to the collector 141 from the return pipe 144.

[0231] In some embodiments, the solar system 140 includes a flow switch 146. The water flow rate can be adjusted by controlling the opening degree of the flow switch 146. The flow switch 146 can be connected to a water supply pipe 143.

[0232] The solar system 140 may include a pressure sensor 147. The pressure sensor 147 may be installed on the water supply pipe 143 and may provide protection when the pressure is high.

[0233] In this application, by connecting the indoor unit heat exchanger 121 of the indoor unit 120, the exhaust side heat exchanger 1372 and the fresh air side heat exchanger 1371 in the fresh air unit 130 in parallel within the refrigeration system, the air conditioner and the fresh air unit can share a single refrigeration system, thereby reducing costs.

[0234] In this application, by integrating the water heat exchanger 142 of the solar system 140 into the fresh air unit 130, and using the water heat exchanger 142 as the regeneration heat source of the adsorption rotor 138, the regeneration efficiency can be improved.

[0235] In this application, by integrating the water heat exchanger 142 of the solar energy system 140 into the fresh air unit 130, the water heat exchanger 142 serves as the regeneration heat source for the adsorption rotor 138, replacing the exhaust side heat exchanger 1372. That is, when the solar energy system 140 is working, the exhaust side heat exchanger 135 can be inactive, and solar energy can replace part of the energy of the refrigeration system, thus achieving energy saving.

[0236] In this application, by setting a first solenoid valve 1191 and a second solenoid valve 1192 on the refrigeration system, three operating modes can be achieved depending on the on / off states of the first solenoid valve 1191 and the second solenoid valve 1192: dehumidification cycle without using solar energy, dehumidification cycle using solar energy but without using condensation heat, and initial cycle using both solar energy and condensation heat. The system can select the appropriate operating mode according to the actual sunlight conditions, maximizing energy savings while ensuring dehumidification effectiveness.

[0237] In some embodiments, refer to Figure 13 and Figure 14 The Fresh Air System 130 is a device that can bring outdoor air into a room.

[0238] The fresh air unit 130 includes a first fresh air heat exchanger 1341 located in the flow path of the fresh air. When used as an evaporator, the first fresh air heat exchanger 1341 can cool and dehumidify the fresh air. When used as a condenser, the first fresh air heat exchanger 1341 can heat the fresh air.

[0239] In the refrigeration system of this application, the compressor 111 is a dual-suction compressor, having a first suction port 1111 and a second suction port 1112. The first suction port 1111 can be connected to the low-pressure chamber of the compressor 111, and the second suction port 1112 can be connected to the medium-pressure chamber of the compressor 111.

[0240] There are two four-way valves: a first four-way valve 1131 and a second four-way valve 1132. The first four-way valve 1131 directs the refrigerant compressed by the compressor to the outdoor heat exchanger 112 in cooling mode and to the first fresh air heat exchanger 1341 in heating mode. The second four-way valve 1132 directs the refrigerant compressed by the compressor to the outdoor heat exchanger 112 in cooling mode and to the indoor unit heat exchanger 121 in heating mode.

[0241] According to an embodiment of this application, in a refrigeration system, the discharge port of compressor 111 is connected to the d-tube of a first four-way valve 1131. The s-tube of the first four-way valve 1131 is connected to the first suction port 1111 of compressor 111.

[0242] The e-pipe of the first four-way valve 1131 is connected to one end of the outdoor heat exchanger 112, and the other end of the outdoor heat exchanger 112 is connected in series with the first electronic expansion valve 1182, the first fresh air heat exchanger 1341, and the c-pipe of the first four-way valve 1131.

[0243] The discharge port of compressor 111 is connected to the d-tube of the second four-way valve 1132. The s-tube of the second four-way valve 1132 is connected to the second suction port 1112 of compressor 111.

[0244] The e-pipe of the second four-way valve 1132 is connected to one end of the outdoor heat exchanger 112, and the other end of the outdoor heat exchanger 112 is connected in series with the air conditioning electronic expansion valve 115, the indoor unit heat exchanger 121, and the c-pipe of the second four-way valve 1132.

[0245] The following example, taken during summer operation, illustrates the flow of the refrigeration system:

[0246] High-temperature, high-pressure refrigerant is discharged from the exhaust port of compressor 111 and then splits into two paths: one path flows to the first four-way valve 1131 to reach the outdoor heat exchanger 112; the other path flows to the second four-way valve 1132 to reach the outdoor heat exchanger 112. At the outdoor heat exchanger 112, the refrigerant transfers heat to the outdoor air and becomes a low-temperature, high-pressure two-phase refrigerant, which then splits into two paths:

[0247] Path 1: After being throttled and depressurized by the first electronic expansion valve 1182, the refrigerant becomes a low-temperature, low-pressure two-phase refrigerant and flows to the first fresh air heat exchanger 1341. Then, it exchanges heat with the fresh air and becomes a high-temperature, low-pressure gaseous refrigerant. Then, it flows to the first four-way valve 1131 and returns to the low-pressure chamber of the compressor 111 through the first suction port 1111.

[0248] Route 2: After being throttled and depressurized by the air conditioning electronic expansion valve 115, the refrigerant becomes a low-temperature, low-pressure two-phase refrigerant and flows to the indoor unit heat exchanger 121 to exchange heat with the indoor air. It absorbs the heat from the indoor air and becomes a high-temperature, low-pressure gaseous refrigerant, which then flows to the second four-way valve 1132 and returns to the compressor's medium-pressure chamber through the second suction port 1112.

[0249] The refrigerant in the low-pressure and medium-pressure chambers is compressed into a high-temperature, high-pressure refrigerant gas inside the compressor.

[0250] Inside the fresh air unit 130, outdoor fresh air is cooled and dehumidified by the first fresh air heat exchanger 1341 before being sent indoors. Inside the indoor unit 120, indoor air is cooled by the indoor unit heat exchanger 121 before being sent indoors.

[0251] The air handling system provided in this application embodiment uses a dual-suction compressor 111, allowing the refrigerant in the circuit containing the first fresh air heat exchanger 1341 of the fresh air unit 130 to flow back to the low-pressure chamber of the compressor 111, while the refrigerant in the circuit containing the indoor unit heat exchanger 121 of the indoor unit 120 flows back to the medium-pressure chamber of the compressor 111. This achieves dual evaporation temperatures with a single refrigeration system, avoiding the complexity and high cost associated with using two separate refrigeration systems. Furthermore, this application allows for separate processing of sensible and latent heat; the high-temperature evaporator of the indoor unit 120 processes sensible heat, while the low-temperature evaporator of the fresh air unit 130 processes latent heat, thus improving system energy efficiency.

[0252] In some embodiments, refer to Figure 15 The fresh air unit 130 may include a second fresh air heat exchanger 1342, which may be located on the air outlet side of the first fresh air heat exchanger 1341. When used as an evaporator, the second fresh air heat exchanger 1342 can cool the fresh air. When used as a condenser, the second fresh air heat exchanger 1342 can heat the fresh air.

[0253] In the refrigeration system, the second fresh air heat exchanger 1342 can be connected in series with the indoor unit heat exchanger 121.

[0254] In this embodiment, the refrigerant flow direction during summer operation is:

[0255] Path 1: After being throttled and depressurized by the first electronic expansion valve 1182, the refrigerant becomes a low-temperature, low-pressure two-phase refrigerant and flows to the first fresh air heat exchanger 1341. Then, it exchanges heat with the fresh air and becomes a high-temperature, low-pressure gaseous refrigerant. Then, it flows to the first four-way valve 1131 and returns to the low-pressure chamber of the compressor 111 through the first suction port 1111.

[0256] Route 2: After being throttled and depressurized by the air conditioning electronic expansion valve 115, the refrigerant becomes a low-temperature, low-pressure two-phase refrigerant and flows to the second fresh air heat exchanger 1342. Then, it exchanges heat with the fresh air and becomes a high-temperature, low-pressure gaseous refrigerant. Then, it flows into the indoor unit heat exchanger 121 and exchanges heat with the indoor air, absorbing the heat from the indoor air and becoming a high-temperature, low-pressure gaseous refrigerant. Then, it flows to the second four-way valve 1132 and returns to the medium-pressure chamber of the compressor through the second suction port 1112.

[0257] Inside the fresh air unit 130, outdoor fresh air is cooled and dehumidified by the first fresh air heat exchanger 1341, and then cooled and dehumidified by the second fresh air heat exchanger 1342 before being sent indoors.

[0258] In some embodiments, refer to Figure 16 The air handling system also includes a third electronic expansion valve 1183. The third electronic expansion valve 1183 may be installed in the fresh air unit 130, or the third electronic expansion valve 1183 may be installed in the indoor unit.

[0259] The air conditioner electronic expansion valve 115, the second fresh air heat exchanger 1342, the third electronic expansion valve 1183, and the indoor unit heat exchanger 121 are connected in series between the outdoor heat exchanger 112 and the c-pipe of the second four-way valve 1132.

[0260] In this embodiment, the refrigerant flow direction during summer operation is:

[0261] Path 1: After being throttled and depressurized by the first electronic expansion valve 1182, the refrigerant becomes a low-temperature, low-pressure two-phase refrigerant and flows to the first fresh air heat exchanger 1341. Then, it exchanges heat with the fresh air and becomes a high-temperature, low-pressure gaseous refrigerant. Then, it flows to the first four-way valve 1131 and returns to the low-pressure chamber of the compressor 111 through the first suction port 1111.

[0262] Route 2: After passing through the air conditioning electronic expansion valve 115 (fully open), the refrigerant flows to the second fresh air heat exchanger 1342, where it exchanges heat with the fresh air and becomes a high-temperature, low-pressure liquid refrigerant. Then, it reaches the third electronic expansion valve 1183, where it is throttled and depressurized to become a low-temperature, low-pressure liquid refrigerant. This refrigerant then flows into the indoor unit heat exchanger 121, where it exchanges heat with the indoor air, absorbing heat from the indoor air and becoming a high-temperature, low-pressure gaseous refrigerant. Finally, it flows to the second four-way valve 1132 and returns to the compressor's medium-pressure chamber through the second suction port 1112.

[0263] Inside the fresh air unit 130, outdoor fresh air is cooled and dehumidified by the first fresh air heat exchanger 1341, and then heated by the second fresh air heat exchanger 1342 before being sent indoors.

[0264] Since the air conditioner's electronic expansion valve 115 is fully open and does not play a role in throttling and reducing pressure, the second fresh air heat exchanger 1342 is used as a condenser to heat the fresh air.

[0265] To prevent the temperature of fresh air from being too low after being cooled and dehumidified by the first fresh air heat exchanger 1341, the heating function of the second fresh air heat exchanger 1342 can be achieved by fully opening the air conditioning electronic expansion valve 115, thereby achieving the purpose of fresh air dehumidification and reheating.

[0266] The embodiments provided in this application achieve dehumidification and reheating of fresh air by connecting a third electronic expansion valve 1183 in series between the second fresh air heat exchanger 1342 and the indoor unit heat exchanger 121. By controlling the air conditioning electronic expansion valve 115 to be fully open, the third electronic expansion valve 1183 throttles and reduces pressure, while not affecting the cooling function of the indoor unit 120.

[0267] In some embodiments, refer to Figure 17 In the refrigeration system, the second fresh air heat exchanger 1342 and the indoor unit heat exchanger 121 are connected in parallel, and the two are connected in parallel between the air conditioning electronic expansion valve 115 and the c-pipe of the second four-way valve 1132.

[0268] The air handling system may include a first flow valve, which may be located within the fresh air unit 130.

[0269] The first flow valve can be a solenoid valve or an electronic expansion valve. In this embodiment, the first flow valve is the fourth electronic expansion valve 1184, which is used as an example.

[0270] The fourth electronic expansion valve 1184 is connected in series on the branch where the second fresh air heat exchanger 1342 is located, and is used to regulate the refrigerant flow at the second fresh air heat exchanger 1342.

[0271] The air handling system may include a second flow valve, which may be located in the indoor unit 120.

[0272] The second flow valve can be a solenoid valve or an electronic expansion valve. In this embodiment, the second flow valve is the fifth electronic expansion valve 1185, which will be used as an example.

[0273] The fifth electronic expansion valve 1185 is connected in series on the branch where the indoor unit heat exchanger 121 is located, and is used to regulate the refrigerant flow at the indoor unit heat exchanger 121.

[0274] In the embodiments provided in this application, by connecting the second fresh air heat exchanger 1342 and the indoor unit heat exchanger 121 in parallel, and controlling the flow of the corresponding branches through the fourth electronic expansion valve 1184 and the fifth electronic expansion valve 1185, the refrigerant flow corresponds to the actual air volume, which can improve the efficiency of the system.

[0275] According to an embodiment of this application, the air handling system may include a fresh air temperature and humidity sensor 136. The fresh air temperature and humidity sensor 136 may be disposed on the windward side of the first fresh air heat exchanger 1341 for detecting the temperature and humidity of the fresh air on the windward side of the first fresh air heat exchanger 1341.

[0276] The air handling system may include a return air temperature and humidity sensor 125. The return air temperature and humidity sensor 125 is located on the windward side of the indoor unit heat exchanger 121 and is used to detect the temperature and humidity of the indoor air.

[0277] The fresh air dew point temperature TL1 can be calculated from the detected value of the fresh air temperature and humidity sensor 136. The temperature of the first fresh air heat exchanger 1341 is TL1 - ΔT. ΔT is a constant.

[0278] Since the first fresh air heat exchanger 1341 needs to dehumidify the fresh air, the temperature of the first fresh air heat exchanger 1341 cannot be lower than the fresh air dew point temperature TL1.

[0279] The indoor air dew point temperature TL2 can be calculated from the value detected by the return air temperature and humidity sensor 125. The minimum temperature of the indoor unit heat exchanger 121 is TL2 + ΔT.

[0280] Since the indoor unit heat exchanger 121 is only used to handle sensible heat, the temperature of the indoor unit heat exchanger 121 cannot be lower than the indoor air dew point temperature TL2.

[0281] The opening ratio of the first electronic expansion valve 1182 and the air conditioning electronic expansion valve 115 is ≥ (TL1-ΔT): (TL2+ΔT).

[0282] In some embodiments, the opening ratio of the fourth electronic expansion valve 1184 and the fifth electronic expansion valve 1185 is (area of ​​the second fresh air heat exchanger * air volume of the fresh air unit) : (area of ​​the indoor unit heat exchanger * air volume of the indoor unit), thereby making the refrigerant flow rate of the parallel branch match the air volume.

[0283] In this application, by using a dual-suction compressor 111, the refrigerant in the circuit containing the first fresh air heat exchanger 1341 of the fresh air unit 130 flows back to the low-pressure chamber of the compressor 111, and the refrigerant in the circuit containing the indoor unit heat exchanger 121 of the indoor unit 120 flows back to the medium-pressure chamber of the compressor 111. Dual evaporation temperatures can be achieved with a single refrigeration system, avoiding the problems of complex system design and high cost caused by using two refrigeration systems.

[0284] In this application, by using a dual-suction compressor 111, the refrigerant in the circuit containing the first fresh air heat exchanger 1341 of the fresh air unit 130 flows back to the low-pressure chamber of the compressor 111, and the refrigerant in the circuit containing the indoor unit heat exchanger 121 of the indoor unit 120 flows back to the medium-pressure chamber of the compressor 111. A single refrigeration system can achieve dual evaporation temperatures. The evaporator of the indoor unit 120 handles sensible heat, and the evaporator of the fresh air unit 130 handles latent heat, which can improve system energy efficiency.

[0285] In this application, by connecting a third electronic expansion valve 1183 in series between the second fresh air heat exchanger 1342 and the indoor unit heat exchanger 121, and by controlling the air conditioning electronic expansion valve 115 to be fully open, the third electronic expansion valve 1183 throttles and reduces pressure, thus achieving dehumidification and reheating of the fresh air without affecting the cooling function of the indoor unit 120.

[0286] In this application, by connecting the second fresh air heat exchanger 1342 and the indoor unit heat exchanger 121 in parallel, and controlling the flow of the corresponding branch through the fourth electronic expansion valve 1184 and the fifth electronic expansion valve 1185, the refrigerant flow corresponds to the actual air volume, thereby improving the system efficiency.

[0287] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0288] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. An air handling system, characterized in that, include: A compressor is used to compress refrigerant; An outdoor heat exchanger is used to perform heat exchange between outdoor air and the refrigerant. An indoor heat exchanger includes an indoor unit heat exchanger and a fresh air heat exchanger, wherein the indoor unit heat exchanger is used to perform heat exchange between indoor air and the refrigerant, and the fresh air heat exchanger is used to perform heat exchange between outdoor fresh air and the refrigerant; A four-way valve is used to direct the refrigerant compressed in the compressor to the outdoor heat exchanger or the indoor heat exchanger, depending on whether the air handling system is in cooling mode or heating mode. An air conditioning electronic expansion valve is connected in series between the outdoor heat exchanger and the indoor heat exchanger; A fresh air electronic expansion valve is connected in series between the outdoor heat exchanger and the fresh air heat exchanger; The air conditioning electronic expansion valve and the indoor unit heat exchanger are connected in series to form the indoor unit branch, the fresh air electronic expansion valve and the fresh air heat exchanger are connected in series to form the fresh air branch, and the fresh air branch and the indoor unit branch are connected in parallel. The compressor, the outdoor heat exchanger, and the four-way valve are located inside the outdoor unit; the indoor heat exchanger is located inside the indoor unit; and the fresh air heat exchanger is located inside the fresh air unit. The air conditioning electronic expansion valve and the fresh air electronic expansion valve are installed in the outdoor unit; or, the air conditioning electronic expansion valve is installed in the indoor unit, and the fresh air electronic expansion valve is installed in the fresh air unit. The air handling system also includes: Controller, used for: The required evaporation pressure for the indoor unit is calculated based on the temperature of the indoor unit's heat exchanger. Calculate the required temperature of the fresh air heat exchanger based on the dew point temperature of the fresh air; obtain the required evaporation pressure of the fresh air unit based on the required temperature of the fresh air heat exchanger. The target evaporation pressure is calculated based on the evaporation pressure required by the indoor unit and the fresh air unit; the compressor frequency is then controlled based on the target evaporation pressure. Wherein, the target evaporation pressure P0 = sensible heat ratio * evaporation pressure required by the indoor unit + (1 - sensible heat ratio) * evaporation pressure required by the fresh air unit; The sensible heat ratio is the proportion of sensible heat load to total load; total load = sensible heat load + latent heat load.

2. The air handling system according to claim 1, characterized in that, The controller is used for: The opening degree of the air conditioner's electronic expansion valve is controlled by: [(required evaporation pressure of the indoor unit - target evaporation pressure) / target evaporation pressure] * initial opening degree; The opening degree of the electronic expansion valve for fresh air is controlled as follows: [(target evaporation pressure - required evaporation pressure of the fresh air unit) / target evaporation pressure] * initial opening degree.

3. The air handling system according to claim 1, characterized in that, The indoor unit has multiple units; the indoor unit includes: An indoor unit electronic expansion valve is connected in series in the indoor unit branch circuit and between the indoor unit heat exchanger and the air conditioning electronic expansion valve; The controller is used for: Sensible heat control steps: Determine whether the difference between the current evaporation pressure of the indoor unit and the required evaporation pressure of the indoor unit is less than the lower limit of the preset range. If so, reduce the opening of the electronic expansion valve of the indoor unit. Determine if the difference between the current evaporation pressure of the indoor unit and the required evaporation pressure of the indoor unit is greater than the upper limit of the preset range. If so, increase the opening of the electronic expansion valve of the indoor unit.

4. The air handling system according to claim 1, characterized in that, The fresh air unit includes: A fresh air flow valve is connected in series in the fresh air branch line to regulate the refrigerant flow rate of the fresh air branch line. The controller is used for: Latent heat control steps: Determine whether the difference between the current evaporation pressure of the fresh air unit and the required evaporation pressure of the fresh air unit is less than the lower limit of the preset range. If so, reduce the opening of the fresh air flow valve. Determine whether the difference between the current evaporation pressure of the fresh air unit and the required evaporation pressure of the fresh air unit is greater than the upper limit of the preset range. If so, increase the opening of the fresh air flow valve.

5. The air handling system according to claim 1, characterized in that, The controller is used for: Sensible heat control steps: Determine whether the temperature of the indoor unit heat exchanger is not less than the sum of the return air dew point temperature and the preset temperature value. If not, increase the opening of the air conditioner electronic expansion valve. Latent heat control steps: Determine whether the temperature of the fresh air heat exchanger is not greater than the difference between the fresh air dew point temperature and the preset temperature value. If not, increase the compressor frequency. If so, the compressor will remain in its current state.

6. The air handling system according to claim 5, characterized in that, The indoor unit includes: An indoor unit flow valve is connected in series in the indoor unit branch circuit to regulate the refrigerant flow rate in the indoor unit branch circuit. The fresh air unit includes: A fresh air flow valve is connected in series in the fresh air branch line to regulate the refrigerant flow rate of the fresh air branch line. The controller is also used for: In the sensible heat control step, if the temperature of the indoor unit heat exchanger is not less than the sum of the return air dew point temperature and the preset temperature value, then it is determined whether the indoor temperature is not greater than the difference between the set temperature and the preset temperature value; if so, the opening of the indoor unit flow valve is reduced; if not, the opening of the indoor unit flow valve is increased. In the latent heat control step, it is determined whether the indoor humidity is not greater than the difference between the set humidity and the preset humidity value. If so, the opening of the fresh air flow valve is reduced; if not, the opening of the fresh air flow valve is increased.

7. The air handling system according to claim 1, characterized in that: The controller is used for: Determine whether the indoor temperature is not greater than the difference between the set temperature and the preset temperature value, and whether the indoor humidity is not greater than the difference between the set humidity and the preset humidity value; if not, the compressor maintains its current state; if so, the compressor shuts down.

8. An air handling system, characterized in that, include: A compressor is used to compress refrigerant; An outdoor heat exchanger is used to perform heat exchange between outdoor air and the refrigerant. An indoor heat exchanger includes an indoor unit heat exchanger and a fresh air heat exchanger, wherein the indoor unit heat exchanger is used to perform heat exchange between indoor air and the refrigerant, and the fresh air heat exchanger is used to perform heat exchange between outdoor fresh air and the refrigerant; A four-way valve is used to direct the refrigerant compressed in the compressor to the outdoor heat exchanger or the indoor heat exchanger, depending on whether the air handling system is in cooling mode or heating mode. An air conditioning electronic expansion valve is connected in series between the outdoor heat exchanger and the indoor heat exchanger; A fresh air electronic expansion valve is connected in series between the outdoor heat exchanger and the fresh air heat exchanger; A subcooling heat exchanger is connected in series between the outdoor heat exchanger and the fresh air electronic expansion valve; The air conditioning electronic expansion valve and the indoor unit heat exchanger form an indoor unit branch, and the fresh air electronic expansion valve, the subcooling heat exchanger and the fresh air heat exchanger form a fresh air branch. The fresh air branch and the indoor unit branch are connected in parallel. The compressor, the outdoor heat exchanger, and the four-way valve are located inside the outdoor unit; the indoor heat exchanger is located inside the indoor unit; and the fresh air heat exchanger is located inside the fresh air unit. The air conditioning electronic expansion valve, the fresh air electronic expansion valve, and the subcooling heat exchanger are installed in the outdoor unit; or, the air conditioning electronic expansion valve is installed in the indoor unit, and the fresh air electronic expansion valve and the subcooling heat exchanger are installed in the fresh air unit. The air handling system also includes: Controller, used for: The required evaporation pressure for the indoor unit is calculated based on the temperature of the indoor unit's heat exchanger. Calculate the required temperature of the fresh air heat exchanger based on the dew point temperature of the fresh air; obtain the required evaporation pressure of the fresh air unit based on the required temperature of the fresh air heat exchanger. The target evaporation pressure is calculated based on the evaporation pressure required by the indoor unit and the fresh air unit; the compressor frequency is then controlled based on the target evaporation pressure. Wherein, the target evaporation pressure P0 = sensible heat ratio * evaporation pressure required by the indoor unit + (1 - sensible heat ratio) * evaporation pressure required by the fresh air unit; The sensible heat ratio is the proportion of sensible heat load to total load; total load = sensible heat load + latent heat load.

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