Air conditioning system and control method thereof

Abstract

The invention provides an air conditioning system and a control method thereof.The air conditioning system comprises a compressor capable of forming refrigerant circulation, a first indoor heat exchanger, a second indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger; refrigerant flowing in the first outdoor heat exchanger and refrigerant flowing in the second outdoor heat exchanger are connected in parallel, the refrigerant in the first outdoor heat exchanger can absorb heat of a first external heat exchange medium, and the refrigerant in the second outdoor heat exchanger can absorb heat of a second external heat exchange medium. And the heat source grade of the first external heat exchange medium is higher than that of the second external heat exchange medium. The refrigerant in the first outdoor heat exchanger absorbs the heat of the first external heat exchange medium, the air suction saturation temperature of the compressor corresponding to the compression cylinder can be increased, the frosting speed of the second outdoor heat exchanger in the heating mode is effectively slowed down, the defrosting frequency is reduced, and then the use comfort of a user is improved; meanwhile, system energy consumption can be reduced, and system energy efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of air conditioning technology, and particularly relates to an air conditioning system and a control method thereof. BACKGROUND

[0002] The air conditioner is used for refrigeration and dehumidification in summer and heating in winter. The conventional household air conditioner causes indoor temperature fluctuation and reduces user comfort when the outdoor heat exchanger is defrosted in winter heating operation, and also increases the energy consumption of the air conditioning system. SUMMARY

[0003] Therefore, the present application provides an air conditioning system and a control method thereof, which can overcome the shortcomings of the prior art that the outdoor heat exchanger is easy to frost when the air conditioning system is in heating mode, which causes large indoor temperature fluctuation, reduces user comfort, and also increases the energy consumption of the air conditioning system.

[0004] To solve the above problems, the present application provides an air conditioning system, which comprises a compressor, a first indoor heat exchanger, a second indoor heat exchanger, a first outdoor heat exchanger and a second outdoor heat exchanger capable of forming a refrigerant circulation. When the air conditioning system is in heating mode, the refrigerant flowing through the first outdoor heat exchanger and the second outdoor heat exchanger forms a parallel connection, the refrigerant in the first outdoor heat exchanger can absorb the heat of a first external heat exchange medium, the refrigerant in the second outdoor heat exchanger can absorb the heat of a second external heat exchange medium, and the heat source grade of the first external heat exchange medium is higher than that of the second external heat exchange medium.

[0005] In some embodiments, the first outdoor heat exchanger has a first heat exchange part in communication with the refrigerant circulation of the air conditioning system and a second heat exchange part in communication with the circulation of the first external heat exchange medium, and the first heat exchange part and the second heat exchange part are connected by thermal coupling.

[0006] In some embodiments, the first outdoor heat exchanger is a double-pipe heat exchanger.

[0007] In some embodiments, the air conditioning system further comprises a fresh air dehumidification device, the fresh air dehumidification device has a fresh air introduction channel and an indoor exhaust channel, and the first outdoor heat exchanger is located at the exhaust port of the indoor exhaust channel.

[0008] In some embodiments, the fresh air dehumidification device comprises a total heat exchanger, and the airflows flowing through the fresh air introduction channel and the indoor exhaust channel respectively form a heat and humidity exchange in the total heat exchanger.

[0009] In some embodiments, the first indoor heat exchanger and the second indoor heat exchanger are both arranged at the air supply port of the fresh air introduction channel and arranged in sequence along the direction of fresh air introduction; and / or, the fresh air introduction channel is provided with an internal circulation return air port, and the internal circulation return air port is provided with a return air valve.

[0010] In some embodiments, the air conditioning system further comprises a first four-way reversing valve and a second four-way reversing valve, the compressor has a first suction port and a second suction port, the first four-way reversing valve and the second four-way reversing valve each have a D port in communication with the exhaust port of the compressor, the first four-way reversing valve has an E port in communication with the first port of the first indoor heat exchanger, an S port in communication with the first suction port, and a C port in communication with the first port of the first outdoor heat exchanger, the second four-way reversing valve has an E port in communication with the first port of the second indoor heat exchanger, an S port in communication with the second suction port, and a C port in communication with the first port of the second outdoor heat exchanger, the second port of the first indoor heat exchanger and the second port of the second indoor heat exchanger are connected at a first point, and a third throttling element is arranged on the pipeline between the first point and the second indoor heat exchanger, the second port of the first outdoor heat exchanger and the second port of the second outdoor heat exchanger are connected at a second point, the first point and the second point are connected, a first throttling element is arranged on the pipeline between the second point and the second port of the second outdoor heat exchanger, and a second throttling element is arranged on the pipeline between the second point and the second port of the first outdoor heat exchanger.

[0011] In some embodiments, the pipeline between the E port of the first four-way reversing valve and the first port of the first indoor heat exchanger is a first pipeline, the pipeline between the S port of the second four-way reversing valve and the second suction port is a second pipeline, and the first pipeline and the second pipeline are controllably connected through an on-off valve; and / or, the compressor is a double-suction single-exhaust single-stage double-cylinder compressor, the displacement of the compression part corresponding to the first suction port and the second suction port of the compressor is V1 and V2, and V1 / V2 is between 0.6 and 1.3.

[0012] The application further provides a control method of the air conditioning system, comprising the following steps: obtaining an operation instruction of the air conditioning system; when the operation instruction is a heating mode, controlling the refrigerant of the air conditioning system to enter the first outdoor heat exchanger and the second outdoor heat exchanger at the same time, controlling the heat exchange between the first external heat medium and the refrigerant in the first outdoor heat exchanger so that the refrigerant in the first outdoor heat exchanger absorbs the heat of the first external heat medium, controlling the D port and the E port of the first four-way reversing valve to be in communication, and the S port and the C port to be in communication, controlling the D port and the E port of the second four-way reversing valve to be in communication, and the S port and the C port to be in communication.

[0013] In some embodiments, when the air conditioning system includes a fresh air dehumidification device, when the operating command is to operate in heating mode, the fresh air fan in the fresh air inlet channel and the exhaust fan in the indoor exhaust channel are also controlled to operate.

[0014] In some embodiments, when the operating command is to operate in cooling and dehumidification mode and the first outdoor heat exchanger includes a first heat exchange section and a second heat exchange section, the second throttling element is controlled to close, and the D port of the first four-way reversing valve is controlled to connect with the C port and the E port and the S port, and the D port of the second four-way reversing valve is controlled to connect with the C port and the E port and the S port; or, When the operating command is to operate the cooling and dehumidification mode and the air conditioning system includes a fresh air dehumidification device, the refrigerant of the air conditioning system is controlled to simultaneously enter the first outdoor heat exchanger and the second outdoor heat exchanger, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger, so that the refrigerant in the first outdoor heat exchanger absorbs the cooling capacity of the first external heat exchange medium. The D port of the first four-way reversing valve is connected to the C port and the E port is connected to the S port, and the D port of the second four-way reversing valve is connected to the C port and the E port is connected to the S port.

[0015] The present invention also provides a control method for an air conditioning system as described above, comprising the following steps: Obtain the operating instructions of the air conditioning system; When the operating command is to operate in heating mode, the refrigerant of the air conditioning system is controlled to simultaneously enter the first outdoor heat exchanger and the second outdoor heat exchanger, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger, so that the refrigerant in the first outdoor heat exchanger absorbs the heat of the first external heat exchange medium. The first four-way reversing valve is controlled to connect the D port and the E port, and the S port and the C port, and the second four-way reversing valve is controlled to connect the D port and the E port, and the S port and the C port, and the on / off valve is controlled to cut off. Alternatively, when the operating command is to operate the cooling and dehumidification mode, the refrigerant of the air conditioning system is controlled to simultaneously enter the first outdoor heat exchanger and the second outdoor heat exchanger, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger, so that the refrigerant in the first outdoor heat exchanger absorbs the cooling capacity of the first external heat exchange medium. The D port of the first four-way reversing valve is connected to the C port and the S port is connected to the E port, the D port of the second four-way reversing valve is connected to the C port and the S port is connected to the E port, and the on / off valve is controlled to cut off. Alternatively, when the operating command is to operate in constant temperature and dehumidification mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger but not the second outdoor heat exchanger, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger, so that the refrigerant in the first outdoor heat exchanger absorbs the cold energy of the first external heat exchange medium. The first four-way reversing valve is controlled to connect port D and port C, and port S and port E, and the second four-way reversing valve is controlled to connect port D and port E. The on / off valve is controlled to open and the first throttling element is closed.

[0016] The air conditioning system and control method provided by this invention have the following beneficial effects: The outdoor side of the air conditioning system is equipped with both a first outdoor heat exchanger and a second outdoor heat exchanger. When the air conditioning system is operating in heating mode, the first outdoor heat exchanger can exchange heat with the first outdoor heat exchanger using the first outdoor heat exchange medium, which has a higher heat source quality. This results in the two outdoor heat exchangers, which act as evaporators in the heating mode, having different evaporation temperatures. The refrigerant in the first outdoor heat exchanger absorbs heat from the first outdoor heat exchange medium, which can increase the suction saturation temperature of the corresponding compressor cylinder. This effectively slows down the frosting speed of the second outdoor heat exchanger in the heating mode, reduces the frequency of defrosting, and thus improves user comfort. At the same time, it can also reduce system energy consumption and improve system energy efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0018] Figure 1 This is a system schematic diagram of the air conditioning system in the first embodiment of the present invention when operating in cooling and dehumidification mode. The diagram shows the flow path of the refrigerant. Figure 2 This is a system schematic diagram of the air conditioning system in the first embodiment of the present invention when operating in heating mode. The diagram shows the flow path of the refrigerant. Figure 3 This is a system schematic diagram of the air conditioning system in the second embodiment of the present invention when it is operating in cooling and dehumidification mode. The diagram shows the flow path of the refrigerant. Figure 4 This is a system schematic diagram of the air conditioning system in the heating mode according to the second embodiment of the present invention. The diagram shows the flow path of the refrigerant. Figure 5 This is a system schematic diagram of the air conditioning system in the third embodiment of the present invention when operating in cooling and dehumidification mode. The diagram shows the flow path of the refrigerant. Figure 6 This is a system schematic diagram of the air conditioning system in the heating mode according to the third embodiment of the present invention. The diagram shows the flow path of the refrigerant. Figure 7 This is a system schematic diagram of the air conditioning system in the third embodiment of the present invention when operating in constant temperature and dehumidification mode. The diagram shows the flow path of the refrigerant.

[0019] The attached figures are labeled as follows: 1. Compressor; 101. First intake port; 102. Second intake port; 103. Exhaust port; 21. First four-way reversing valve; 22. Second four-way reversing valve; 31. First outdoor heat exchanger; 32. Second outdoor heat exchanger; 41. First throttling element; 42. Second throttling element; 43. Third throttling element; 51. First indoor heat exchanger; 52. Second indoor heat exchanger; 6. Total heat exchanger; 7. Fresh air filter; 8. On / off valve; 9. Second heat exchange section; 10. Return air valve; 11. Fresh air valve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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 on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0022] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0023] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0024] See also Figures 1 to 7 As shown in the embodiment of the present invention, an air conditioning system is provided, including a compressor 1 capable of forming a refrigerant cycle, a first indoor heat exchanger 51, a second indoor heat exchanger 52, a first outdoor heat exchanger 31, and a second outdoor heat exchanger 32. When the air conditioning system is operating in heating mode, the refrigerant flowing in the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32 are connected in parallel. The refrigerant in the first outdoor heat exchanger 31 can absorb heat from a first external heat exchange medium, and the refrigerant in the second outdoor heat exchanger 32 can absorb heat from a second external heat exchange medium. The heat source quality of the first external heat exchange medium is higher than that of the second external heat exchange medium. In a specific embodiment, the aforementioned second outer ring heat exchange medium can be outdoor airflow. It should be noted that the aforementioned heat source quality of the first external heat exchange medium being higher than that of the second external heat exchange medium refers to a condition that should be met when the air conditioning system is operating in heating mode. However, when the air conditioning system is operating in cooling mode or other modes, the aforementioned heat relationship does not necessarily need to be met.

[0025] In this technical solution, the outdoor side of the air conditioning system is equipped with both a first outdoor heat exchanger 31 and a second outdoor heat exchanger 32. When the air conditioning system is in heating mode, the first outdoor heat exchanger 31 can exchange heat with the first external heat exchange medium, which has a higher heat source quality. This allows the two outdoor heat exchangers, which act as evaporators in the heating mode, to have different evaporation temperatures. The refrigerant in the first outdoor heat exchanger 31 absorbs the heat from the first external heat exchange medium, which can increase the suction saturation temperature of the corresponding compressor cylinder. This effectively slows down the frosting speed of the second outdoor heat exchanger 32 in the heating mode, reduces the defrosting frequency, and improves user comfort. At the same time, it can also reduce system energy consumption and improve system energy efficiency.

[0026] As a first embodiment of the present invention (e.g.) Figure 1 and Figure 2 The air conditioning system shown has a first heat exchange section (not labeled in the figure) in the first outdoor heat exchanger 31 that is in circulation with the refrigerant of the air conditioning system and a second heat exchange section 9 that is in circulation with the first external heat exchange medium. The first heat exchange section and the second heat exchange section 9 are thermally coupled. The aforementioned thermal coupling means that the refrigerant in the first heat exchange section can exchange heat with the first external heat exchange medium in the second heat exchange section 9. The aforementioned first external heat exchange medium can be hot water provided by a solar water heater or domestic hot water drainage connected to the user, etc., and the second external heat exchange medium is the airflow in the external environment.

[0027] In some embodiments, the first outdoor heat exchanger 31 is a shell-and-tube heat exchanger with high anti-icing and anti-blocking capabilities, which can ensure its reliable operation in low-temperature environments.

[0028] As a second embodiment of the present invention, the air conditioning system further includes a fresh air dehumidification device (not shown in the figure), which has a fresh air inlet channel (not shown in the figure) and an indoor exhaust channel (not shown in the figure). The first outdoor heat exchanger 31 is located at the exhaust port of the indoor exhaust channel. It is understood that a fresh air fan (not shown in the figure) is provided at the air outlet of the aforementioned fresh air inlet channel, and a fresh air filter 7 and a fresh air valve 11 that can control the entry of fresh air are provided at the air inlet. An exhaust fan (not shown in the figure) is provided in the indoor exhaust channel to exhaust indoor air from the exhaust port of the indoor exhaust channel. In this embodiment, the first outdoor heat exchanger 31 can specifically be a finned tube heat exchanger or a microchannel heat exchanger, etc., which are heat exchangers that exchange heat between refrigerant and air.

[0029] In this technical solution, the first outdoor heat exchanger 31 is installed in the indoor exhaust duct so that the indoor exhaust airflow can be used to form a high-efficiency heat exchange with the first outdoor heat exchanger 31. That is, the aforementioned first external heat exchange medium is the indoor exhaust airflow. Since the temperature of the indoor exhaust airflow is regulated by the air conditioner, when heating, the heat of the exhaust airflow will be recovered and utilized by the refrigerant of the first outdoor heat exchanger 31, which significantly improves the system energy efficiency of the air conditioning system in the heating mode and reduces system energy consumption. When the air conditioning system is cooling, the exhaust airflow absorbs the heat of the refrigerant of the first outdoor heat exchanger 31, thus improving the system energy efficiency of the air conditioning system in the cooling mode and reducing system energy consumption.

[0030] In some embodiments, the fresh air dehumidification device includes a total heat exchanger 6, in which the airflows flowing in the fresh air inlet channel and the indoor exhaust channel exchange heat.

[0031] In this technical solution, by setting up a total heat exchanger 6 in the fresh air dehumidification device, the fresh air and exhaust air can exchange heat in the total heat exchanger 6 during the process of introducing fresh air. The heat exchange between the exhaust air and the fresh air can be used to pre-adjust the temperature of the fresh air, reduce system energy consumption, and further improve system energy efficiency.

[0032] In some embodiments, the first indoor heat exchanger 51 and the second indoor heat exchanger 52 are both located at the air outlet (not marked in the figure) of the fresh air introduction channel, and are arranged sequentially back and forth along the direction of fresh air introduction. In this way, the first indoor heat exchanger 51 and the second indoor heat exchanger 52 arranged back and forth can form a stepped heat exchange (heating or cooling) for the introduced fresh air or return air. Especially when the air conditioning system is operating in cooling and dehumidification mode, the aforementioned first indoor heat exchanger 51 and the second indoor heat exchanger 52 arranged back and forth can achieve stepped cooling and dehumidification of fresh air or return air, reduce irreversible losses in the heat exchange process, and improve the cooling energy efficiency ratio and the dehumidification amount per unit energy consumption.

[0033] In some embodiments, the fresh air inlet channel is provided with an internal circulation return air inlet (not indicated in the figure), and the internal circulation return air inlet is provided with a return air valve 10. Specifically, when a large flow of fresh air needs to be introduced into the room, the return air valve 10 can be controlled to be completely closed to ensure that a large amount of outdoor fresh air can enter the indoor space to improve indoor air quality. The return air valve 10 can also be controlled to open at a certain angle to realize the mixed air mode of fresh air and return air.

[0034] In some embodiments, the air conditioning system further includes a first four-way reversing valve 21 and a second four-way reversing valve 22. The compressor 1 has a first suction port 101 and a second suction port 102. The first four-way reversing valve 21 and the second four-way reversing valve 22 each have a D port that communicates with the discharge port of the compressor 1. The first four-way reversing valve 21 has an E port that communicates with the first port of the first indoor heat exchanger 51, an S port that communicates with the first suction port 101, and a C port that communicates with the first port of the first outdoor heat exchanger 31. The second four-way reversing valve 22 has an E port that communicates with the first port of the second indoor heat exchanger 52, an S port that communicates with the second suction port 102, and a C port that communicates with the first port of the second outdoor heat exchanger 32. The second port of the first indoor heat exchanger 51 and the second port of the second indoor heat exchanger 52 are connected at a first point. Furthermore, a third throttling element 43 is provided on the pipeline between the first point and the second indoor heat exchanger 52. The second port of the first outdoor heat exchanger 31 and the second port of the second outdoor heat exchanger 32 are connected to the second point. The first point and the second point are connected. A first throttling element 41 is provided on the pipeline between the second point and the second port of the second outdoor heat exchanger 32. A second throttling element 42 is provided on the pipeline between the second point and the second port of the first outdoor heat exchanger 31. The aforementioned throttling elements can specifically be electronic expansion valves. In a specific embodiment, the aforementioned compressor 1 is a dual-intake single-exhaust single-stage dual-cylinder compressor. In a preferred embodiment, the displacement of the compression section corresponding to the first intake port 101 and the second intake port 102 of the compressor 1 is V1 and V2, respectively, and V1 / V2 is between 0.6 and 1.3.

[0035] In this technical solution, through the flow path switching function of the aforementioned first four-way reversing valve 21 and second four-way reversing valve 22, and the throttling and flow control of the first throttling element 41, second throttling element 42, and third throttling element 43, the air conditioning system can switch between cooling and dehumidification and heating, ensuring that the air conditioning system meets the user's needs.

[0036] As a third embodiment of the present invention (a further improvement based on the second embodiment), the pipeline between the E port of the first four-way reversing valve 21 and the first port of the first indoor heat exchanger 51 is the first pipeline (not marked in the figure), and the pipeline between the S port of the second four-way reversing valve 22 and the second air intake 102 is the second pipeline (not marked in the figure). The first pipeline and the second pipeline are controllably connected by an on / off valve 8, which is specifically an electromagnetic on / off valve.

[0037] In this technical solution, by setting the on / off valve 8, the controllable connection and disconnection between the E port of the first four-way reversing valve 21 and the S port of the second four-way reversing valve 22 can be realized, which can meet the structural requirements of the air conditioning system when operating in constant temperature and dehumidification mode, and further enrich the operating mode of the air conditioning system.

[0038] According to an embodiment of the present invention, a control method for an air conditioning system as described above is also provided, comprising the following steps: Obtain the operating instructions of the air conditioning system; When the operating command is to operate in heating mode, the refrigerant of the air conditioning system is controlled to simultaneously enter the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger 31, so that the refrigerant in the first outdoor heat exchanger 31 absorbs the heat of the first external heat exchange medium. The first four-way reversing valve 21 is controlled to connect port D and port E, and port S and port C, and the second four-way reversing valve 22 is controlled to connect port D and port E, and port S and port C.

[0039] In this technical solution, when the air conditioning system is operating in heating mode, it can utilize a first external heat exchange medium with a higher heat grade to form heat exchange with the first outdoor heat exchanger 31. This allows the two outdoor heat exchangers, which act as evaporators in heating mode, to have different evaporation temperatures. The refrigerant in the first outdoor heat exchanger 31 absorbs the heat from the first external heat exchange medium, which can increase the suction saturation temperature of the corresponding compressor. This effectively slows down the frosting speed of the outdoor heat exchanger in heating mode, reduces the frequency of defrosting, and thus improves user comfort. At the same time, it can also reduce system energy consumption and improve system energy efficiency.

[0040] See Figure 2As shown, in the first embodiment, when the air conditioning system is operating in heating mode, the D pipe (i.e., the aforementioned D port) and E pipe (i.e., the aforementioned E port) of the first four-way reversing valve 21 and the second four-way reversing valve 22 are connected, and the C pipe (i.e., the aforementioned C port) and S pipe (i.e., the aforementioned S port) are connected. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 is divided into two paths. One path enters the first indoor heat exchanger 51 (i.e., the indoor heat exchanger on the windward side) through the D and E pipes of the first four-way reversing valve 21 and condenses and releases heat to become liquid. The other path enters the second indoor heat exchanger 52 (i.e., the indoor heat exchanger on the leeward side) through the D and E pipes of the second four-way reversing valve 22 and condenses and releases heat to become liquid. After being initially throttled by the third throttling element 43, it merges with the refrigerant discharged from the first indoor heat exchanger 51. The incoming liquid refrigerant is mixed, and the mixed refrigerant is divided into two paths. After being throttled and depressurized by the first throttling element 41 and the second throttling element 42, it enters the second outdoor heat exchanger 32 and the first outdoor heat exchanger 31 to absorb heat and vaporize into refrigerant gas. The gaseous refrigerant flowing out of the first outdoor heat exchanger 31 enters the first suction port 101 of the compressor 1 through the C and S tubes of the first four-way reversing valve 21. The gaseous refrigerant flowing out of the second outdoor heat exchanger 32 enters the second suction port 102 of the compressor 1 through the C and S tubes of the second four-way reversing valve 22. After the refrigerant entering the first suction port 101 and the second suction port 102 of the compressor is compressed in its respective compression cylinder, the exhaust gas is mixed and discharged through the exhaust port 103, thus completing the entire heating cycle. In this embodiment, the first outdoor heat exchanger 31 is preferably a water-refrigerant heat exchanger of a shell-and-tube heat exchanger. In the heating mode, the water entering the first outdoor heat exchanger 31 can be hot water from a solar water heater or domestic hot water discharged from the room, so as to increase the intake saturation temperature of the first compression cylinder and improve the system energy efficiency.

[0041] See Figure 4As shown, in the second embodiment, during heating mode operation, both the first four-way reversing valve 21 and the second four-way reversing valve 22 have their D and E pipes connected, and their C and S pipes connected. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 is divided into two paths. One path enters the first indoor heat exchanger 51 through the D and E pipes of the first four-way reversing valve 21, where it condenses and releases heat to become liquid. The other path enters the second indoor heat exchanger 52 through the D and E pipes of the second four-way reversing valve 22, where it condenses and releases heat to become liquid. The subcooled liquid refrigerant condensed and released by the second indoor heat exchanger 52 is initially throttled by the third throttling element 43, and then its pressure is reduced by the second throttling element 42 and the first throttling element 41 (two throttling elements). The components also serve as flow distribution components, entering the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32 respectively. In these components, the refrigerant evaporates and absorbs heat to form a low-pressure gaseous state. The gaseous refrigerant flowing out of the first outdoor heat exchanger 31 enters the first suction port 101 of the compressor 1 through the C and S tubes of the first four-way reversing valve 21. The gaseous refrigerant flowing out of the second outdoor heat exchanger 32 enters the second suction port 102 of the compressor 1 through the C and S tubes of the second four-way reversing valve 22. After the refrigerant entering the first suction port 101 and the second suction port 102 of the compressor is compressed in its respective compression cylinder, the exhaust mixture is discharged from the exhaust port 103, thus completing the entire heating cycle.

[0042] The heating mode has two evaporation pressures, and the first outdoor heat exchanger 31 in the indoor exhaust duct can recover the heat carried away by the indoor exhaust, reducing the system's energy consumption.

[0043] In some embodiments, when the air conditioning system includes a fresh air dehumidification device, when the operating command is to operate in heating mode, the system also controls the operation of the fresh air fan in the fresh air inlet channel and the exhaust fan in the indoor exhaust channel to drive the introduction of fresh air and the exhaust of indoor air.

[0044] In some embodiments, when the operating command is to operate in cooling and dehumidification mode and the first outdoor heat exchanger 31 includes a first heat exchange section and a second heat exchange section 9, the second throttling element 42 is controlled to close, and the D port of the first four-way reversing valve 21 is controlled to connect with the C port and the E port and the S port, and the D port of the second four-way reversing valve 22 is controlled to connect with the C port and the E port and the S port, which corresponds to the aforementioned first embodiment; or, when the operating command is to operate in cooling and dehumidification mode and the air conditioning system includes a fresh air dehumidification device, the refrigerant of the air conditioning system is controlled to simultaneously enter the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger 31, so that the refrigerant in the first outdoor heat exchanger 31 absorbs the cold energy of the first external heat exchange medium, and the D port of the first four-way reversing valve 21 is controlled to connect with the C port and the E port and the S port, and the D port of the second four-way reversing valve 22 is controlled to connect with the C port and the E port and the S port, which corresponds to the aforementioned second embodiment.

[0045] See Figure 1 As shown, in the first embodiment, during cooling mode operation, both the first four-way reversing valve 21 and the second four-way reversing valve 22 have their D and C pipes open and their S and E pipes open. At this time, the second throttling element 42 is fully closed. The high-temperature, high-pressure refrigerant gas discharged from the compressor enters the second outdoor heat exchanger 32 through the D and C pipes of the second four-way reversing valve 22, where it releases heat and condenses into high-pressure liquid refrigerant. The high-pressure liquid refrigerant that releases heat and condenses in the condenser is throttled and depressurized by the first throttling element 41 and then divided into two paths: one path evaporates and absorbs heat in the first indoor heat exchanger 51 and then passes through the first four-way reversing valve. The E and S ends of valve 21 enter the first suction port 101 of the compressor; the other refrigerant enters the second indoor heat exchanger 52 after being further throttled and depressurized by the third throttling element 43. After evaporating and absorbing heat in the second indoor heat exchanger 52, it enters the second suction port 102 of the compressor through the E and S pipes of the second four-way reversing valve 22. The refrigerants entering the first suction port 101 and the second suction port 102 of the compressor are compressed into a high-pressure superheated state in their respective compression cylinders and then mixed and discharged, thus completing the entire refrigeration cycle.

[0046] In this mode, the first indoor heat exchanger 51 and the second indoor heat exchanger 52 serve as a high-temperature evaporator and a low-temperature evaporator, respectively. The indoor return air is cooled and dehumidified in stages by the high and low temperature evaporators. The staged heat exchange can reduce the irreversible loss in the heat exchange process between the air and the indoor heat exchanger, thereby improving the system's energy efficiency.

[0047] See Figure 3As shown, in the second embodiment, during cooling mode operation, both the first four-way reversing valve 21 and the second four-way reversing valve 22 have their D and C pipes open and their S and E pipes open. The high-temperature, high-pressure refrigerant gas discharged from the compressor enters the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32 through the D and C pipes of the first four-way reversing valve 21 and the second four-way reversing valve 22, respectively, where it releases heat and condenses into high-pressure liquid refrigerant. At this time, the first throttling element 41 and the second throttling element 42, in addition to throttling and reducing pressure, also play a role in regulating the refrigerant flow distribution between the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32. The refrigerant after throttling and reducing pressure... There are two paths: one path involves the refrigerant evaporating and absorbing heat in the first indoor heat exchanger 51, and then entering the first suction port 101 of the compressor through the E and S ends of the first four-way reversing valve 21; the other path involves the refrigerant being further throttled and depressurized by the third throttling element 43 before entering the second indoor heat exchanger 52. After evaporating and absorbing heat in the second indoor heat exchanger 52, the refrigerant enters the second suction port 102 of the compressor through the E and S pipes of the second four-way reversing valve 22. The refrigerants entering the first suction port 101 and the second suction port 102 of the compressor are compressed in their respective compression cylinders and then discharged mixed with the exhaust gas, thus completing the entire refrigeration cycle.

[0048] In this mode, the first indoor heat exchanger 51 and the second indoor heat exchanger 52 serve as a high-temperature evaporator and a low-temperature evaporator, respectively. The high-temperature evaporator is mainly responsible for the sensible heat load, and the low-temperature evaporator is mainly responsible for the latent heat load. The return air is cooled and dehumidified by the high and low temperature evaporators in stages, reducing irreversible losses in the heat exchange process and improving the system's energy efficiency ratio.

[0049] According to a third embodiment of the present invention, a control method for an air conditioning system as described above is also provided, comprising the following steps: Obtain the operating instructions of the air conditioning system; When the operating command is to operate in heating mode, the refrigerant of the air conditioning system simultaneously enters the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32, and the first external heat exchange medium exchanges heat with the refrigerant in the first outdoor heat exchanger 31, so that the refrigerant in the first outdoor heat exchanger 31 absorbs the heat of the first external heat exchange medium. The first four-way reversing valve 21 is connected to ports D and E, and ports S and C; the second four-way reversing valve 22 is connected to ports D and E, and ports S and C; and the on / off valve 8 is shut off. Alternatively, when the operating command is to operate in cooling / dehumidification mode, the air conditioning system... The refrigerant simultaneously enters the first outdoor heat exchanger 31 and the second outdoor heat exchanger 32, and controls the heat exchange between the first external heat exchange medium and the refrigerant in the first outdoor heat exchanger 31, so that the refrigerant in the first outdoor heat exchanger 31 absorbs the cold energy of the first external heat exchange medium. It also controls the D port and C port of the first four-way reversing valve 21 to be connected, and the S port and E port to be connected. It controls the D port and C port of the second four-way reversing valve 22 to be connected, and the S port and E port to be connected. It controls the on / off valve 8 to be cut off. Specifically, in the third embodiment, the control method when the air conditioning system is running in heating mode and cooling / dehumidification mode is the same as that in the second embodiment, and will not be repeated here.

[0050] Unlike the second embodiment, when the operating command is to operate in constant temperature and dehumidification mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger 31 but not the second outdoor heat exchanger 32. Furthermore, the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger 31, so that the refrigerant in the first outdoor heat exchanger 31 absorbs the cooling capacity of the first external heat exchange medium. Additionally, the D port and C port of the first four-way reversing valve 21 are connected, and the S port and E port are connected. The D port and E port of the second four-way reversing valve 22 are connected. The on / off valve 8 is connected, and the first throttling element 41 is closed. Specifically, see [link to specific details]. Figure 7As shown, during constant temperature dehumidification mode operation, the D and C pipes and the E and S pipes of the first four-way reversing valve 21 are connected, and the D and E pipes and the S and C pipes of the second four-way reversing valve 22 are connected. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 is divided into two paths. One path enters the first outdoor heat exchanger 31 through the D and C pipes of the first four-way reversing valve 21, condenses and releases heat to become liquid refrigerant, and then is throttled and depressurized by the second throttling element 42. The other path of refrigerant discharged from the compressor enters the second indoor heat exchanger 52 through the D and E pipes of the second four-way reversing valve 22 for heat exchange, condenses and releases heat to become liquid refrigerant, and then is throttled and depressurized by the third throttling element 43, and then flows through the second throttling element 42. The depressurized refrigerant is mixed and then enters the first indoor heat exchanger 51, where it evaporates and absorbs heat to become gaseous. This gaseous refrigerant is divided into two paths and enters the two suction ports of the compressor. One path enters the second suction port 102 of the compressor directly through the on / off valve 8, while the other path is drawn into the first suction port 101 of the compressor through the E and S pipes of the first four-way reversing valve 21. After the refrigerant entering the first suction port 101 and the second suction port 102 of the compressor is compressed in its respective compression cylinder, the exhaust gases are mixed and discharged, thus completing the entire reheat dehumidification cycle.

[0051] In this mode, the first throttling element 41 is in a fully closed state, the second outdoor heat exchanger 32 is in a short-circuit state and does not participate in the system circulation, and the other end of the second outdoor heat exchanger 32 is connected to the C and S pipes of the second four-way reversing valve 22, and is in a low-pressure state, so there is no refrigerant migration problem. The first indoor heat exchanger 51 acts as an evaporator to cool and dehumidify the indoor air, and the second indoor heat exchanger 52 acts as a low-temperature condenser to reheat the cooled and dehumidified air, so that the low-temperature and low-humidity air after passing through the dehumidifying evaporator is sent into the room at a temperature close to the return air temperature, thereby improving the comfort of the indoor environment.

[0052] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. An air conditioning system, characterized in that, The system includes a compressor (1) capable of forming a refrigerant cycle, a first indoor heat exchanger (51), a second indoor heat exchanger (52), a first outdoor heat exchanger (31), and a second outdoor heat exchanger (32). When the air conditioning system is in heating mode, the refrigerant flowing in the first outdoor heat exchanger (31) and the second outdoor heat exchanger (32) are connected in parallel. The refrigerant in the first outdoor heat exchanger (31) can absorb the heat of the first external heat exchange medium, and the refrigerant in the second outdoor heat exchanger (32) can absorb the heat of the second external heat exchange medium. The heat source grade of the first external heat exchange medium is higher than that of the second external heat exchange medium.

2. The air conditioning system according to claim 1, characterized in that, The first outdoor heat exchanger (31) has a first heat exchange section that is in circulation with the refrigerant of the air conditioning system and a second heat exchange section (9) that is in circulation with the first external heat exchange medium. The first heat exchange section and the second heat exchange section (9) are thermally coupled together.

3. The air conditioning system according to claim 2, characterized in that, The first outdoor heat exchanger (31) is a shell-and-tube heat exchanger.

4. The air conditioning system according to claim 1, characterized in that, It also includes a fresh air dehumidification device, which has a fresh air inlet channel and an indoor exhaust channel, with the first outdoor heat exchanger (31) located at the exhaust port of the indoor exhaust channel.

5. The air conditioning system according to claim 4, characterized in that, The fresh air dehumidification device includes a total heat exchanger (6), and the airflows flowing in the fresh air inlet channel and the indoor exhaust channel respectively form a heat and moisture exchange in the total heat exchanger (6).

6. The air conditioning system according to claim 4, characterized in that, The first indoor heat exchanger (51) and the second indoor heat exchanger (52) are both located at the air outlet of the fresh air inlet channel and are arranged sequentially back and forth along the direction of fresh air introduction; and / or, the fresh air inlet channel is provided with an internal circulation return air outlet, and the internal circulation return air outlet is provided with a return air valve (10).

7. The air conditioning system according to any one of claims 1 to 6, characterized in that, It also includes a first four-way reversing valve (21) and a second four-way reversing valve (22). The compressor (1) has a first suction port (101) and a second suction port (102). The first four-way reversing valve (21) and the second four-way reversing valve (22) each have a D port that is connected to the exhaust port of the compressor (1). The first four-way reversing valve (21) has an E port that is connected to the first port of the first indoor heat exchanger (51), an S port that is connected to the first suction port (101), and a C port that is connected to the first port of the first outdoor heat exchanger (31). The second four-way reversing valve (22) has an E port that is connected to the first port of the second indoor heat exchanger (52), and an S port that is connected to the second suction port (102). Port C is connected to the first port of the second outdoor heat exchanger (32). The second port of the first indoor heat exchanger (51) is connected to the second port of the second indoor heat exchanger (52) at a first point. A third throttling element (43) is provided on the pipeline between the first point and the second indoor heat exchanger (52). The second port of the first outdoor heat exchanger (31) is connected to the second port of the second outdoor heat exchanger (32) at a second point. The first point is connected to the second point. A first throttling element (41) is provided on the pipeline between the second point and the second port of the second outdoor heat exchanger (32). A second throttling element (42) is provided on the pipeline between the second point and the second port of the first outdoor heat exchanger (31).

8. The air conditioning system according to claim 7, characterized in that, The pipeline between the E port of the first four-way reversing valve (21) and the first port of the first indoor heat exchanger (51) is the first pipeline, and the pipeline between the S port of the second four-way reversing valve (22) and the second suction port (102) is the second pipeline. The first pipeline and the second pipeline are controllably connected by an on / off valve (8); and / or, the compressor (1) is a double-suction single-discharge single-stage double-cylinder compressor, and the displacement of the compressor (1) and the compression section corresponding to the first suction port (101) and the second suction port (102) are V1 and V2 respectively, and V1 / V2 is between 0.6 and 1.

3.

9. A control method for an air conditioning system as described in claim 7, characterized in that, Includes the following steps: Obtain the operating instructions of the air conditioning system; When the operation command is to operate in heating mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger (31) and the second outdoor heat exchanger (32) at the same time, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger (31) so that the refrigerant in the first outdoor heat exchanger (31) absorbs the heat of the first external heat exchange medium, and the D port of the first four-way reversing valve (21) is controlled to connect with the E port and the S port and the C port, and the D port of the second four-way reversing valve (22) is controlled to connect with the E port and the S port and the C port.

10. The control method for an air conditioning system according to claim 9, characterized in that, When the air conditioning system includes a fresh air dehumidification device, when the operating command is to operate in heating mode, it also controls the operation of the fresh air fan in the fresh air inlet channel and the exhaust fan in the indoor exhaust channel.

11. The control method for an air conditioning system according to claim 9, characterized in that, When the operating command is to operate in cooling and dehumidification mode and the first outdoor heat exchanger (31) includes a first heat exchange section and a second heat exchange section (9), the second throttling element (42) is controlled to close, and the D port of the first four-way reversing valve (21) is controlled to connect with the C port and the E port and the S port, and the D port of the second four-way reversing valve (22) is controlled to connect with the C port and the E port and the S port; or, When the operating command is to operate the cooling and dehumidification mode and the air conditioning system includes a fresh air dehumidification device, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger (31) and the second outdoor heat exchanger (32) at the same time, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger (31) so that the refrigerant in the first outdoor heat exchanger (31) absorbs the cold energy of the first external heat exchange medium, and the D port of the first four-way reversing valve (21) is controlled to connect with the C port and the E port and the S port, and the D port of the second four-way reversing valve (22) is controlled to connect with the C port and the E port and the S port.

12. A control method for an air conditioning system as described in claim 8, characterized in that, Includes the following steps: Obtain the operating instructions of the air conditioning system; When the operation command is to operate in heating mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger (31) and the second outdoor heat exchanger (32) at the same time, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger (31) so that the refrigerant in the first outdoor heat exchanger (31) absorbs the heat of the first external heat exchange medium, and the D port of the first four-way reversing valve (21) is connected to the E port and the S port is connected to the C port, the D port of the second four-way reversing valve (22) is connected to the E port and the S port is connected to the C port, and the on / off valve (8) is controlled to cut off. Alternatively, when the operating command is to run the cooling and dehumidification mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger (31) and the second outdoor heat exchanger (32) at the same time, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger (31) so that the refrigerant in the first outdoor heat exchanger (31) absorbs the cold energy of the first external heat exchange medium, and the D port of the first four-way reversing valve (21) is controlled to connect with the C port and the S port and the E port, the D port of the second four-way reversing valve (22) is controlled to connect with the C port and the S port and the E port, and the on / off valve (8) is controlled to cut off; Alternatively, when the operating command is to operate in constant temperature and dehumidification mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger (31) instead of the second outdoor heat exchanger (32), and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger (31) so that the refrigerant in the first outdoor heat exchanger (31) absorbs the cold energy of the first external heat exchange medium. The D port of the first four-way reversing valve (21) is connected to the C port and the S port is connected to the E port. The D port of the second four-way reversing valve (22) is connected to the E port. The on / off valve (8) is connected and the first throttling element (41) is closed.

13. A control method for an air conditioning system as described in claim 7, characterized in that, Includes the following steps: Obtain the operating instructions of the air conditioning system; When the operation command is to operate in heating mode, the refrigerant of the air conditioning system is controlled to enter the first outdoor heat exchanger (31) and the second outdoor heat exchanger (32) at the same time, and the first external heat exchange medium is controlled to exchange heat with the refrigerant in the first outdoor heat exchanger (31) so that the refrigerant in the first outdoor heat exchanger (31) absorbs the heat of the first external heat exchange medium, and the D port of the first four-way reversing valve (21) is controlled to connect with the E port and the S port and the C port, and the D port of the second four-way reversing valve (22) is controlled to connect with the E port and the S port and the C port.

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