Air conditioner fresh air system with switchable heating and refrigerating double-loop mode

Abstract

The invention relates to an air conditioner fresh air system with switchable heating and refrigerating double-loop modes, an air circulation system and a cold circulation system, the air circulation system comprises a fresh air system and an exhaust system, and a lower air pipeline, an air circulation four-way valve, an air return pipeline and an exhaust pipeline communicate in sequence; a fresh air inlet pipeline, a fresh air supply pipeline, an air circulation four-way valve and an upper air pipeline are sequentially communicated, and a refrigerating mode of lower suction and upper blowing is started; an upper air pipeline, an air circulation four-way valve, an air return pipeline and an exhaust pipeline are sequentially communicated, a fresh air inlet pipeline, a fresh air supply pipeline, the air circulation four-way valve and a lower air pipeline are sequentially communicated, an upper-suction and lower-blowing heating mode is started, and the phenomenon of vertical temperature stratification caused by direct sinking of cold air during traditional refrigeration is effectively broken through convection; cold air is prevented from being excessively gathered at the head of the human body, the temperature difference between the head and the foot area is remarkably reduced, meanwhile, through circulation treatment of air sucked from the bottom, cold waste is further reduced, and the refrigeration efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of building air conditioning, and in particular to an air conditioning fresh air system with switchable heating and cooling dual-circuit modes. Background Art

[0002] Building air conditioning and ventilation systems are core components of modern building environmental control. By integrating temperature regulation, humidity control, and air replacement functions, they ensure both thermal comfort and air quality within enclosed spaces. Their core function is to transport purified fresh outdoor air indoors while simultaneously exhausting polluted air and regulating indoor temperature through cooling and heating modules.

[0003] Current mainstream air conditioning systems primarily utilize single-duct centralized air supply or VRV (multi-split) decentralized control. Centralized systems deliver treated air to various areas via a network of ducts, often employing either upward-feeding and downward-returning or side-feeding and side-returning airflow arrangements at the terminal. Multi-split systems rely on indoor units to independently control local temperatures, with fresh air introduced via independent ducts or heat exchangers. Both systems utilize a four-way valve in the cold cycle to switch refrigerant flow to achieve cooling / heating mode switching. The fresh air handling unit typically operates in conjunction with the main AC unit, employing either a fixed air speed or a simple variable air volume strategy.

[0004] Traditional architectures have significant comfort shortcomings: First, the single air supply mode leads to rigid airflow organization. Under cooling conditions, low-temperature air sinks rapidly due to its high density, which can easily cause large vertical temperature differences in the area where people move around, resulting in a suitable temperature above the head but too cold at the feet. During heating, hot air is affected by buoyancy and is retained in the ceiling, resulting in insufficient heating in the floor area, causing the uncomfortable feeling of "hot head and cold feet". Second, temperature stratification exacerbates energy waste, requiring the system to operate at high power continuously to compensate for heat loss, and it cannot accurately match human thermal needs. Third, fixed air supply angles and wind speeds make it difficult to dynamically adapt to seasonal differences, exacerbating local overcooling / overheating problems and reducing the overall thermal environment uniformity and response efficiency. Summary of the Invention

[0005] The present application provides an air-conditioning fresh air system with switchable heating and cooling dual-circuit modes, which can solve at least one of the above-mentioned technical problems.

[0006] The present application provides an air conditioning fresh air system with switchable heating and cooling dual-circuit modes, which adopts the following technical solutions: A heating and cooling dual-circuit mode switchable air conditioning fresh air system, comprising: The fresh air system includes a fresh air inlet duct and a fresh air supply duct connected to each other, wherein a fresh air heat exchanger and an air supply fan are sequentially arranged in the fresh air supply duct along the wind direction; The exhaust system includes a return air duct and an exhaust air duct connected to each other, wherein an exhaust heat exchanger and an exhaust fan are sequentially arranged in the exhaust air duct along the wind direction; The upwind duct and the downwind duct are connected to the outlet end of the fresh air supply duct and the return air end of the return air duct via an air circulation four-way valve, the pipe opening of the upwind duct away from the air circulation four-way valve faces upward, and the pipe opening of the downwind duct away from the air circulation four-way valve faces downward; and A cold circulation system, comprising a connected compressor, a cold circulation four-way valve, the fresh air heat exchanger, a throttle valve and the exhaust air heat exchanger; When the cold circulation system starts the cooling mode, the downwind duct, the air circulation four-way valve, the return air duct and the exhaust duct are connected in sequence, and the fresh air inlet duct, the fresh air supply duct, the air circulation four-way valve and the upwind duct are connected in sequence, and the internal circulation rapid cooling mode of downward suction and upward blowing is started; When the cold circulation system starts the heating mode, the upwind duct, the air circulation four-way valve, the return air duct and the exhaust duct are connected in sequence, and the fresh air inlet duct, the fresh air supply duct, the air circulation four-way valve and the downwind duct are connected in sequence, and the internal circulation rapid heating mode of upper suction and lower blowing is started.

[0007] Optionally, the exhaust system further includes a heat exchange duct, and the return air duct can selectively communicate with the exhaust duct through the heat exchange duct, or directly communicate with the exhaust duct; The fresh air system further includes a heat exchange coil located in the heat exchange pipe, wherein the heat exchange coil is connected between the fresh air inlet pipe and the fresh air supply pipe; Among them, when the return air duct, the heat exchange duct and the exhaust duct are connected, and the fresh air inlet duct, the heat exchange coil and the fresh air supply duct are connected, the energy-saving mode is turned on.

[0008] Optionally, the return air duct and the fresh air supply duct may be selectively connected; When the return air duct is connected to the exhaust air duct, and the fresh air inlet duct is connected to the fresh air supply duct, the high-speed ventilation mode is turned on; The return air duct is connected to the fresh air supply duct and the exhaust duct. When the fresh air inlet duct and the fresh air supply duct are connected, the low-speed ventilation mode is turned on.

[0009] Optionally, the return air duct, the heat exchange duct and the exhaust duct are connected, the return air duct and the fresh air supply duct are connected, the fresh air inlet duct, the heat exchange coil and the fresh air supply duct are connected, and the secondary heat exchange mode is turned on.

[0010] Optionally, the exhaust system also includes an air collecting box, and the fresh air supply duct, the fresh air inlet duct, and the return air duct are all connected to the air collecting box through a regulating valve. The connecting port between the air collecting box and the fresh air supply duct is a return air port, and the connecting port between the heat exchange coil and the fresh air supply duct is a fresh air port. The return air port and the fresh air port have different directions.

[0011] Optionally, the return air outlet and the fresh air outlet are oriented perpendicularly to each other.

[0012] Optionally, a humidifier is provided in the fresh air supply duct, and the humidifier is located in the fresh air path and the return air path, and before the fresh air heat exchanger.

[0013] Optionally, a filter is provided in the fresh air supply duct, and the filter is on the fresh air path and located before the fresh air heat exchanger.

[0014] Optionally, the filter is on the return air path.

[0015] Optionally, the air circulation four-way valve is an electric manual four-way valve.

[0016] In summary, this application includes at least one of the following beneficial technical effects: 1. The downwind duct, air circulation four-way valve, return air duct and exhaust duct are connected in sequence, and the fresh air inlet duct, fresh air supply duct, air circulation four-way valve and upwind duct are connected in sequence, and the internal circulation rapid cooling mode with downward suction and upward blowing is started; the upwind duct, air circulation four-way valve, return air duct and exhaust duct are connected in sequence, and the fresh air inlet duct, fresh air supply duct, air circulation four-way valve and downwind duct are connected in sequence, and the internal circulation rapid heating mode with upward suction and downward blowing is started; The "downward suction and upward blowing" internal circulation rapid cooling mode and the "upward suction and downward blowing" internal circulation rapid heating mode effectively break the vertical temperature stratification phenomenon caused by the direct sinking of cold air in traditional refrigeration through the synergistic effect of forced convection and natural convection, avoid excessive accumulation of cold air at the height of the human head, and significantly reduce the temperature difference between the head and foot areas. At the same time, through the circulation treatment of the air sucked in from the bottom, the waste of cold air is further reduced and the cooling efficiency is improved.

[0017] 2. The return air duct, heat exchange duct and exhaust duct are connected, and the fresh air inlet duct, heat exchange coil and fresh air supply duct are connected, and the energy-saving mode is turned on; When the exhaust air flows through the exhaust duct, the waste heat (in winter) or waste cold (in summer) it carries will be absorbed by the heat exchange coil. The air in the heat exchange coil comes from the fresh air inlet duct. After heat exchange, the temperature-adjusted fresh air is then sent into the fresh air supply duct. The fresh air is preheated in winter and precooled in summer, effectively reducing the system's dependence on the compressor during operation.

[0018] 3. When the return air duct is connected to the exhaust duct, and the fresh air inlet duct is connected to the fresh air supply duct, the high-speed ventilation mode is turned on; when the return air duct is connected to the fresh air supply duct and the exhaust duct at the same time, and the fresh air inlet duct is connected to the fresh air supply duct, the low-speed ventilation mode is turned on to adapt to different indoor scenes.

[0019] 4. Turn on the low-speed ventilation mode and start the heat exchange coil at the same time. The fresh air is input at a relatively slow speed, and the return air is slowly discharged through the heat exchange duct and the exhaust duct. Part of the indoor air exchanges heat with the fresh air, and part of it is mixed with the fresh air and returned to the room. Turn on the secondary heat exchange mode. Through staged energy recovery and utilization, the system greatly reduces the operating burden of the fresh air heat exchanger and the exhaust air heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a piping layout diagram of a fresh air air conditioning system with switchable heating and cooling dual-circuit modes provided in an embodiment of the present application; Figure 2 Used to demonstrate the airflow direction of the air conditioning fresh air system with switchable heating and cooling dual-circuit modes provided in the embodiment of the present application; Figure 3 Used to demonstrate the airflow direction of the fast ventilation in the heating mode of the air-conditioning fresh air system with switchable heating and cooling dual-circuit modes provided in the embodiment of the present application; Figure 4 Used to demonstrate the airflow direction of the fast ventilation in cooling mode of the air-conditioning fresh air system with switchable heating and cooling dual-circuit modes provided in the embodiment of the present application; Figure 5 Used to demonstrate the airflow direction of the secondary heat exchange mechanism of the air-conditioning fresh air system with switchable heating and cooling dual-circuit modes provided in the embodiment of the present application.

[0021] Description of reference numerals: 1. Fresh air system; 11. Fresh air inlet duct; 12. Fresh air supply duct; 13. Supply air fan; 14. Heat exchange coil; 15. Humidifier; 16. Filter; 2. Exhaust system; 21. Return air duct; 22. Exhaust duct; 23. Exhaust fan; 24. Heat exchange duct; 25. Air collecting box; 3. Upwind duct; 4. Downwind duct; 5. Air circulation four-way valve; 6. Cold circulation system; 61. Compressor; 62. Cold circulation four-way valve; 63. Fresh air heat exchanger; 64. Throttle valve; 65. Exhaust air heat exchanger; 7. Regulating valve. DETAILED DESCRIPTION

[0022] The following will be combined with the Figure 1-5, clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0023] The embodiment of the present application discloses an air conditioning fresh air system with switchable heating and cooling dual circuit modes. Figure 1 The air conditioning fresh air system includes an air circulation system, and the air circulation system includes a fresh air system 1, an exhaust system 2 and a double air duct structure, realizing the integrated design of air conditioning and fresh air functions.

[0024] Fresh air system 1 includes a connected fresh air inlet duct 11 and a fresh air supply duct 12. Fresh air supply duct 12 is sequentially located downwind of a filter 16, a humidifier 15, a fresh air heat exchanger 63, and a supply fan 13. These ducts are responsible for drawing in fresh air from outside, exchanging heat with it, and then delivering it indoors. Exhaust system 2 includes a connected return air duct 21 and an exhaust duct 22. Exhaust duct 22 is sequentially located downwind of an exhaust heat exchanger 65 and an exhaust fan 23 for exhausting indoor air.

[0025] The dual-duct structure includes an upflow duct 3 and a downflow duct 4. The dual-duct structure is connected to the outlet end of the fresh air supply duct 12 and the return air end of the return air duct 21 via a four-way air circulation valve 5. The pipe opening of the upflow duct 3, which is away from the four-way air circulation valve 5, faces upward, while the pipe opening of the downflow duct 4, which is away from the four-way air circulation valve 5, faces downward. The four-way air circulation valve 5 can be either an electric valve or a manual valve. This embodiment employs a dual-purpose electric-manual four-way valve. This design combines the automation of electric control with the flexibility of manual operation, which is particularly critical during system debugging, automatic control failures, or emergency situations, and is adaptable to complex environmental requirements.

[0026] The air conditioning fresh air system also includes a cold circulation system 6, which includes a connected compressor 61, a cold circulation four-way valve 62, a fresh air heat exchanger 63, a throttle valve 64 and an exhaust air heat exchanger 65, and realizes the conversion between cooling and heating modes by switching the refrigerant flow direction.

[0027] In the heating mode, the cold cycle four-way valve 62 guides the refrigerant circuit to the heating path by switching the interface status (interface a is connected to interface d, and interface b is connected to interface c): the high-temperature and high-pressure gaseous refrigerant output by the compressor 61 first enters the fresh air heat exchanger 63 (acting as a condenser), where it releases heat to heat the fresh air and then condenses and liquefies into liquid refrigerant. After the liquid refrigerant is reduced in pressure by the throttle valve 64, it enters the exhaust air heat exchanger 65 (acting as an evaporator) to absorb heat from the exhaust air and then re-gasify. The refrigerant evaporates into a low-temperature gas and returns to the compressor 61 to complete the cycle, thus completing the heating cycle.

[0028] At the same time, the air circulation four-way valve 5 adjusts the air duct connection relationship (refer to Figure 3 , interface b is connected with d, and interface a is connected with c), so that the upwind duct 3 and the return air duct 21 form a suction channel, and the downwind duct 4 and the fresh air supply duct 12 form a blowing channel.

[0029] Because hot air has a lower density, the cool air in the room naturally sinks to the bottom. The system then blows the heated fresh air evenly and slowly toward the floor through the downwind duct 4. Buoyancy forces the hot air to naturally rise and gradually mix with the cool air layer at the bottom. Simultaneously, the upwind duct 3 at the top continuously draws in the relatively warmer air from the upper part of the room, which is then transported through the return air duct 21 to the exhaust system 2 for heat exchange before being discharged. This "upward suction, downward blowing" airflow circulation pattern, through the synergistic effect of forced air supply and natural convection, effectively overcomes the vertical temperature imbalance caused by traditional heating, where hot air accumulates at the top of the room. It prevents the floor from being heated due to rising hot air and significantly reduces the temperature difference between the feet and head. Experimental data shows that this mode can raise the floor temperature to 22-24°C, a 4-6°C increase compared to traditional heating modes, while keeping the vertical temperature difference within 2°C, improving comfort by approximately 35%. Through the coordinated design of bottom directional air supply and top return air, the heat utilization rate is increased by 18%-25%, and the energy consumption is reduced by 10%-15% under the same heating demand.

[0030] In the cooling mode, the cold cycle four-way valve 62 guides the refrigerant circuit to the cooling path by switching the interface status (interface a is connected with interface b, and interface c is connected with interface d): the high-temperature and high-pressure gaseous refrigerant output by the compressor 61 first enters the exhaust air heat exchanger 65 (acting as a condenser), releases heat through heat dissipation, and is converted into a medium-temperature and high-pressure liquid refrigerant. The liquid refrigerant then flows through the throttle valve 64 to reduce the pressure and temperature to form a low-temperature and low-pressure gas-liquid mixture, and finally enters the fresh air heat exchanger 63 (acting as an evaporator) to absorb heat from the indoor air and vaporize, while lowering the indoor temperature. The formed low-temperature and low-pressure gas enters the compressor 61 again for circulation.

[0031] At the same time, the air circulation four-way valve 5 adjusts the air duct connection relationship (refer to Figure 4 , interface b is connected to interface c, interface a is connected to interface d), so that the downwind duct 4 and the return air duct 21 form a suction channel, and the upwind duct 3 and the fresh air supply duct 12 form a blowing channel.

[0032] Because cold air has a higher density than hot air, the hot air in the room naturally accumulates in the upper part of the space. The system then blows the cooled fresh cold air evenly and slowly toward the top of the room through the upwind duct 3. The cold air naturally sinks under gravity and gradually mixes with the warm air layer in the room. Simultaneously, the downwind duct 4 at the bottom continuously draws in the relatively cooler air from the bottom of the room, which is then transported through the return air duct 21 to the exhaust system 2 for heat exchange before being discharged. This "downward suction and upward blowing" airflow circulation pattern, through the synergistic effect of forced and natural convection, effectively breaks the vertical temperature stratification caused by the direct downward movement of cold air in traditional cooling. This prevents excessive accumulation of cold air at head height and significantly reduces the temperature difference between the head and feet. Furthermore, the circulation of the air drawn in from the bottom further reduces cooling waste and improves cooling efficiency. Experimental data shows that this mode can control the vertical temperature difference in the room to within 1.5°C, compared to the 3-5°C temperature difference of traditional air conditioning systems, improving comfort by approximately 40% and reducing cooling energy consumption by 15%-20%.

[0033] Further, refer to Figure 1 The exhaust system 2 also includes a heat exchange duct 24 and an air collection box 25. The return air duct 21 can selectively communicate with the exhaust duct 22 via the heat exchange duct 24, or directly with the exhaust duct 22. The return air duct 21 and the exhaust duct 22 are connected by a regulating valve 7. The fresh air inlet duct 11, the fresh air supply duct 12, and the return air duct 21 are all connected to the air collection box 25 via a regulating valve 7.

[0034] The fresh air system 1 further includes a heat exchange coil 14 located in the heat exchange pipe 24 , and the heat exchange coil 14 is connected between the fresh air inlet pipe 11 and the fresh air supply pipe 12 .

[0035] Among them, when the return air duct 21, the heat exchange duct 24 and the exhaust duct 22 are connected, and the fresh air inlet duct 11, the heat exchange coil 14 and the fresh air supply duct 12 are connected, the energy-saving mode is turned on.

[0036] Reference Figure 5In energy-saving mode, the exhaust air in the exhaust system 2 flows through the heat exchange pipe 24, and the excess heat (in winter) or excess cold (in summer) it carries will be absorbed by the heat exchange coil 14. The air in the heat exchange coil 14 comes from the fresh air inlet duct 11. After heat exchange, the temperature-regulated fresh air is then sent to the fresh air supply duct 12. This energy recovery mechanism allows the fresh air to be preheated in winter and precooled in summer, effectively reducing the system's dependence on the compressor 61 during operation. When operating in energy-saving mode, the system's energy saving rate can be increased by 20%-30%, which is particularly suitable for use in continuous operation scenarios of heating in winter or cooling in summer. It not only reduces energy consumption, but also provides a pre-treatment method for fresh air by recovering energy from the exhaust air, indirectly improving indoor air quality. At the same time, it also reduces the burden on the main heat exchanger and extends the service life of the equipment, so that the entire system achieves a good balance between energy saving, comfort and efficient operation.

[0037] By providing an air collecting box 25, the return air duct 21 and the fresh air supply duct 12 can be selectively connected, and the high-speed ventilation mode and the low-speed ventilation mode in the air-conditioning fresh air system can be flexibly switched according to the indoor air quality and actual use needs.

[0038] When the return air duct 21 is connected to the exhaust air duct 22 (refer to Figure 2 The fresh air inlet duct 11 is connected to the fresh air supply duct 12 (refer to Figure 2 When the light turns green, the system starts the high-speed ventilation mode. At this time, the regulating valve 7 is opened to a large extent, a large amount of fresh air flows in, and the indoor air is quickly discharged. The ventilation efficiency is significantly improved. It is suitable for indoor environments with dense personnel, frequent activities or poor air quality. It can quickly reduce the indoor carbon dioxide concentration and reduce odor accumulation.

[0039] When the return air duct 21 is connected to the fresh air supply duct 12 (refer to Figure 2 Medium purple direction), exhaust duct 22 (refer to Figure 2 The fresh air inlet duct 11 is connected to the fresh air supply duct 12 (refer to Figure 2 When the light (green) is moving in the middle, the system enters low-speed ventilation mode. The opening range of regulating valve 7 is appropriately reduced, allowing fresh air to enter at a slower rate and return air to be discharged slowly. This mode provides a relatively gentle ventilation process, ensuring both indoor air freshness and a relatively stable indoor temperature, avoiding large temperature fluctuations caused by excessive ventilation. Furthermore, low-speed ventilation allows more time for fresh air and indoor air to mix, resulting in a more uniform temperature distribution. This mode is particularly suitable for use in environments with few people, good air quality, and high requirements for temperature stability, effectively balancing air quality and comfort.

[0040] Reference Figure 5When the return air duct 21 is connected to the air collecting box 25, the fresh air supply duct 12 and the heat exchange duct 24 are both connected to the air collecting box 25, and the heat exchange duct 24 is connected to the exhaust duct 22 (purple and brown directions), a low-speed ventilation mode can be achieved. Simultaneously, the heat exchange coil 14 is activated, fresh air is input at a relatively slow rate (green direction), and the return air is slowly discharged through the heat exchange duct 24 and exhaust duct 22. Part of the indoor air exchanges heat with the fresh air, and part of it mixes with the fresh air and returns to the room, forming a secondary heat exchange mechanism. The connection between the air collecting box 25 and the fresh air supply duct 12 is the return air port, and the connection between the heat exchange coil 14 and the fresh air supply duct 12 is the fresh air port. The return air port and the fresh air port face different directions.

[0041] In this embodiment, Figure 5 As shown, the return air inlet and the fresh air inlet are oriented perpendicularly. Some return air flows in from right to left, while fresh air flows in from bottom to top within the fresh air supply duct 12. When the fresh air enters the duct from below with a certain speed and kinetic energy, it impacts the return air flowing from right to left. This impact forces the two airflows to form complex turbulence and swirl within the duct, actively breaking the laminar boundary between the return air and the fresh air, allowing for full mixing of the fresh air and return air, increasing momentum exchange and heat transfer between the airflows.

[0042] For example, during winter heating, the 25°C warm air exhausted from the indoor space flows through the return air duct 21 and heat exchange duct 24. Based on a heat recovery efficiency of 65%-70%, this preheats the fresh air entering the heat exchange coil 14 from -5°C to 5°C-8°C (first-stage preheating). Simultaneously, the exhaust air temperature is reduced to 12°C-15°C, effectively reducing heat loss. The fresh air, after the first-stage preheating, then enters the fresh air supply duct 12, where it mixes with a portion of the return air within the duct (e.g., if the return air temperature is 25°C, the fresh air and return air are mixed in a 1:1 ratio). After heat exchange, the fresh air temperature is further raised to 15°C-17°C (second-stage preheating). It is then heated by the fresh air heat exchanger 63 and finally delivered to the indoor space. This two-stage preheating mechanism allows the fresh air to undergo two temperature adjustments before being heated by the fresh air heat exchanger 63, fully utilizing the residual heat in the exhaust air. This reduces the heating burden of the air conditioning system and improves energy efficiency.

[0043] The principle is similar during summer cooling. Through phased energy recovery and utilization, the system significantly reduces the operating burden of the fresh air heat exchanger 63 and the exhaust air heat exchanger 65. This is particularly effective in cold or hot climates, achieving significant energy savings. It also effectively prevents the impact of large fresh air temperature fluctuations on indoor comfort, making indoor temperature transitions more natural and further improving the overall performance of the air conditioning system and the user experience.

[0044] In the air conditioning fresh air system, the air collecting box 25, a key component of the exhaust system 2, achieves flexible control over the air duct connectivity by interposing a regulating valve 7 between the fresh air supply duct 12, the fresh air intake duct 11, and the return air duct 21. Essentially, the air collecting box 25 is a chamber for collecting and distributing airflow. By adjusting the opening and closing degree of the regulating valve 7 and the connectivity status, it can precisely adjust the air volume and pressure to meet the needs of different operating modes.

[0045] For example, when the system needs to switch to energy-saving mode, the air collecting box 25 cooperates with the regulating valve 7 to close the direct connection between the fresh air inlet duct 11 and the fresh air supply duct 12, opens the connection of the heat exchange duct 24, and guides the gas to flow to the heat exchange coil 14 to achieve energy recovery. This structure significantly improves the system's ability to regulate airflow by optimizing the airflow path and reduces the energy loss caused by air duct switching. In addition, the degree of opening of the regulating valve 7 can be controlled to dynamically adjust the air volume distribution to ensure that the ideal air quality and temperature balance are always maintained indoors. In actual applications, this flexible air duct adjustment mechanism not only enhances the versatility of the system, but also effectively improves the overall operating efficiency of the system, so that the air conditioning fresh air system achieves a better balance between energy saving, comfort and efficient operation.

[0046] Reference Figure 1 Humidifier 15 can effectively regulate the humidity of the air entering the room in both the fresh air and return air paths. Humidifier 15 uses steam injection or ultrasonic atomization to evenly disperse water molecules into the airflow. In the fresh air path, it humidifies the fresh air introduced from the outside. This is especially important in dry winters or when the indoor humidity drops due to long-term air conditioning operation, replenishing the humidity and making the air more moist and comfortable. In the return air path, humidifying the returning indoor air further regulates the indoor humidity balance.

[0047] Humidifier 15 operates before fresh air heat exchanger 63. When the humidified air enters the heat exchanger, the appropriate humidity improves the air's heat transfer performance, thereby increasing heat exchange efficiency. For example, as air humidity increases, its specific heat capacity also increases, which helps absorb or release more heat, enabling the heat exchanger to perform heat exchange more efficiently.

[0048] The filter 16 is installed in the fresh air path and the return air path, in the fresh air supply duct 12, and before the heat exchanger in the fresh air path. It can effectively filter out impurities, dust, pollen and other particulate matter in the air. The filter 16 filters the fresh air and return air before they enter the heat exchanger, which can prevent impurities from adhering to the surface of the heat exchanger and affecting the heat exchange efficiency. The filter 16 is made of various materials, and different filters 16 are generally selected according to the application scenario. For example, in a home environment, a primary filter 16 can be used, such as non-woven fabrics, HEPA, activated carbon, electrostatic dust removal filters and other materials, which are relatively low in cost and can filter out larger particles of dust, hair, etc. In places with high air quality requirements, such as hospitals and laboratories, a high-efficiency filter 16 can be used, which has a filtration efficiency of ≥99.97% for particles with a particle size ≥0.3μm, and effectively filters bacteria, viruses and other microorganisms. In areas with severe air pollution or where extremely high air cleanliness requirements are required, an ultra-high efficiency filter 16 can be used, achieving a filtration efficiency of ≥99.999% for particles ≥0.1μm, ensuring high air cleanliness standards. The installation of filter 16 not only improves indoor air quality but also protects the heat exchanger from impurities, extending its service life and improving overall system efficiency, ensuring that the air conditioning system can stably and efficiently provide a clean, comfortable indoor air environment.

[0049] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0050] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0051] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. An air conditioning fresh air system with switchable heating and cooling dual-circuit modes, characterized in that: include: A fresh air system (1) comprises a fresh air inlet duct (11) and a fresh air supply duct (12) which are connected to each other, wherein a fresh air heat exchanger (63) and an air supply fan (13) are sequentially arranged in the fresh air supply duct (12) along the wind direction; An exhaust system (2) includes a return air duct (21) and an exhaust air duct (22) connected to each other, wherein an exhaust air heat exchanger (65) and an exhaust air fan (23) are sequentially arranged in the exhaust air duct (22) along the wind direction; The upwind duct (3) and the downwind duct (4) are connected to the outlet end of the fresh air supply duct (12) and the return air end of the return air duct (21) via an air circulation four-way valve (5); the pipe opening of the upwind duct (3) away from the air circulation four-way valve (5) faces upward, and the pipe opening of the downwind duct (4) away from the air circulation four-way valve (5) faces downward; as well as A cold circulation system (6) comprising a connected compressor (61), a cold circulation four-way valve (62), the fresh air heat exchanger (63), a throttle valve (64) and the exhaust air heat exchanger (65); When the cold circulation system (6) starts the cooling mode, the downwind duct (4), the air circulation four-way valve (5), the return air duct (21) and the exhaust duct (22) are connected in sequence, and the fresh air inlet duct (11), the fresh air supply duct (12), the air circulation four-way valve (5) and the upwind duct (3) are connected in sequence, and the internal circulation rapid cooling mode of downward suction and upward blowing is started; When the cooling circulation system (6) starts the heating mode, the upper air duct (3), the air circulation four-way valve (5), the return air duct (21) and the exhaust air duct (22) are connected in sequence, and the fresh air inlet duct (11), the fresh air supply duct (12), the air circulation four-way valve (5) and the downwind duct (4) are connected in sequence, and the internal circulation rapid heating mode of upward suction and downward blowing is started.

2. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 1 is characterized in that: The exhaust system (2) further includes a heat exchange pipe (24), and the return air pipe (21) can selectively communicate with the exhaust pipe (22) through the heat exchange pipe (24), or directly communicate with the exhaust pipe (22); The fresh air system (1) further comprises a heat exchange coil (14) located in the heat exchange pipe (24), wherein the heat exchange coil (14) is connected between the fresh air inlet pipe (11) and the fresh air supply pipe (12); When the return air duct (21), the heat exchange duct (24) and the exhaust duct (22) are connected, and the fresh air inlet duct (11), the heat exchange coil (14) and the fresh air supply duct (12) are connected, the energy-saving mode is turned on.

3. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 2 is characterized in that: The return air duct (21) and the fresh air supply duct (12) can be selectively connected; Wherein, when the return air duct (21) and the exhaust air duct (22) are connected, and the fresh air inlet duct (11) and the fresh air supply duct (12) are connected, the high-speed ventilation mode is turned on; The return air duct (21) is connected to the fresh air supply duct (12) and the exhaust duct (22). When the fresh air inlet duct (11) and the fresh air supply duct (12) are connected, a low-speed ventilation mode is turned on.

4. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 3 is characterized in that: The return air duct (21), the heat exchange duct (24) and the exhaust duct (22) are connected, the return air duct (21) and the fresh air supply duct (12) are connected, the fresh air inlet duct (11), the heat exchange coil (14) and the fresh air supply duct (12) are connected, and the secondary heat exchange mode is turned on.

5. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 2 is characterized in that: The exhaust system (2) further comprises an air collecting box (25), the fresh air supply duct (12), the fresh air inlet duct (11), and the return air duct (21) are all connected to the air collecting box (25) via a regulating valve (7), the connecting port between the air collecting box (25) and the fresh air supply duct (12) is a return air port, the connecting port between the heat exchange coil (14) and the fresh air supply duct (12) is a fresh air port, and the return air port and the fresh air port have different directions.

6. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 5, characterized in that: The return air outlet and the fresh air outlet are oriented perpendicularly to each other.

7. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 1 is characterized in that: A humidifier (15) is provided in the fresh air supply duct (12). The humidifier (15) is located on the fresh air path and the return air path and before the fresh air heat exchanger (63).

8. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 1, characterized in that: A filter (16) is provided in the fresh air supply duct (12), and the filter (16) is on the fresh air path and located before the fresh air heat exchanger (63).

9. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 8, characterized in that: The filter (16) is on the return air path.

10. The air conditioning fresh air system with switchable heating and cooling dual-circuit modes according to claim 1, characterized in that: The air circulation four-way valve (5) is an electric manual four-way valve.

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