Outdoor integrated fresh air air conditioning unit with heat recovery and control method

Abstract

The application discloses an outdoor integrated fresh air air conditioning unit with heat recovery and a control method, which comprises a box body, wherein the box body is provided with left-right symmetrical fresh air inlets and exhaust air inlets, the top of the box body is provided with a supply air outlet and a return air outlet which are connected with indoor pipelines respectively, the inside of the box body is divided into four chambers, i.e., a left upper chamber, a left lower chamber, a right upper chamber and a right lower chamber, by a wind valve assembly, and each chamber is switched between two completely independent air duct topological structures by different opening and closing combinations of the wind valve; a heat recovery device is horizontally arranged in the middle of the box body, a fresh air fan is arranged in the right lower chamber of the box body, an inner coil is arranged in the right upper chamber of the box body above the fresh air fan, a return air fan is arranged in the left upper chamber of the box body, and an outer coil is arranged in the left lower chamber of the box body below the return air fan. The application can realize free switching between a pure air conditioning internal circulation mode and a heat pipe energy-saving fresh air external circulation mode, and simultaneously has the functions of air conditioning temperature adjustment, fresh air ventilation and exhaust air waste heat recovery.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an outdoor integrated fresh air conditioning unit with heat recovery and its control method. Background Technology

[0002] Currently, household fresh air conditioners and air source heat pump air conditioners have several inherent defects in the industry: (1) Low integration of fresh air and air conditioning systems and high energy consumption: Most existing household air conditioners do not have fresh air exchange function. Long-term indoor closed internal circulation will cause the indoor oxygen content to decrease and pollutants to accumulate. It is necessary to open windows for ventilation. Opening windows for ventilation will introduce outdoor cold and heat loads, which will greatly increase the energy consumption of air conditioning operation and reduce indoor comfort. A small number of air conditioners with fresh air function on the market cannot completely isolate the fresh air channel. Under the condition that only indoor temperature adjustment is required and no ventilation is required, outdoor air will continue to infiltrate into the room, and cold and heat loads will continue to invade, resulting in high energy consumption. If independent fresh air units and split air conditioners are configured separately, there will be a large number of devices, complicated supporting pipelines, large installation space, and high construction costs.

[0003] (2) Thermal short circuit problem in outdoor air conditioner: The distance between the fresh air inlet and the exhaust outlet of the outdoor unit of traditional household air conditioner and independent fresh air heat exchange unit is close. The high temperature hot air discharged from the condenser is easily drawn back into the fresh air inlet, forming a thermal short circuit, which causes the condensing temperature to rise, the compressor cooling efficiency to decrease, and the power consumption of the whole unit to increase.

[0004] (3) Redundant equipment structure and low fan utilization: Traditional fresh air heat recovery equipment and air conditioner outdoor unit heat dissipation fan are arranged independently, with a large number of parts, large overall size, high operating noise, high manufacturing cost, single function of various fans and non-reusable, and low integration of the overall structure.

[0005] (4) Household paper heat exchange core has hygiene defects: Currently, household bidirectional air fresh air equipment generally uses paper heat exchange core. The core has the problem of water vapor exchange between fresh air and exhaust air, which can easily lead to cross-contamination of odors. In long-term high humidity environment, mold is very easy to grow. In low temperature environment, the core is easy to freeze and block the air duct, causing the equipment to fail.

[0006] Based on the above defects and shortcomings, it is necessary to improve the existing technology and design an outdoor integrated fresh air conditioning unit with heat recovery and a control method. Summary of the Invention

[0007] The main technical problem solved by this invention is to provide an outdoor integrated fresh air conditioning unit with heat recovery, which solves the defects of existing units such as low integration, inability to freely switch between internal and external circulation, serious thermal short circuit, high energy consumption, redundant overall structure, and poor hygiene of paper heat exchange core.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: providing an outdoor integrated fresh air air conditioning unit with heat recovery, including an outdoor housing, on which fresh air inlets and exhaust outlets are symmetrically distributed, and on the top of the housing are supply air inlets and return air inlets that are respectively connected to indoor ducts. The interior of the housing is divided into four chambers (upper left, lower left, upper right, and lower right) by a damper assembly. Each chamber switches between two completely independent air duct topologies by different combinations of opening and closing dampers. A heat recovery device is arranged horizontally in the middle of the housing. A fresh air fan is arranged in the lower right chamber of the housing. An inner coil is arranged in the upper right chamber above the fresh air fan. A return air fan is arranged in the upper left chamber of the housing. An outer coil is arranged in the lower left chamber below the return air fan. The enclosure serves as an air heat exchange unit and does not have a built-in compressor unit. Instead, it is connected to an independent variable frequency compressor. The main unit of the variable frequency compressor integrates a four-way valve, a liquid receiver, and a throttling element. The refrigeration components are connected to the inner and outer coils respectively through refrigerant copper pipes to form a complete refrigeration / heating cycle.

[0009] Preferably, the fresh air fan and the return air fan are EC volute-less insertion fans or AC fans.

[0010] Preferably, the air valve assembly includes a first air valve installed at the lower part of the vertical partition inside the housing, a third air valve installed at the upper part of the partition, a second air valve placed horizontally in the middle of the housing to separate the fresh air inlet and the supply air outlet, and a fourth air valve to separate the return air outlet and the exhaust air outlet.

[0011] Preferably, the air valve is a low-leakage electrically sealed air valve, the air valve blades are covered with an EPDM ethylene propylene diene monomer rubber sealing layer, and the joint between the air valve body and the housing is filled with an EPDM foam sealing gasket.

[0012] Preferably, the heat recovery device adopts a partitioned gravity heat pipe structure and is filled with a low-boiling-point heat exchange medium.

[0013] Preferably, a primary filter is installed inside the fresh air inlet, and an insect screen is installed outside the exhaust air outlet; gravity check valves are installed at the external duct positions of the supply and return air outlets.

[0014] Preferably, the outer side of the enclosure is coated with a thermal insulation and waterproof coating, the fan drive circuit board and electrical control components are centrally arranged in an independent sealed moisture-proof chamber, and the bottom of the enclosure is integrated with a condensate tray and an external drain outlet.

[0015] Preferably, the enclosure has a built-in electronic control system. The controller of the electronic control system collects the indoor CO2 concentration, indoor and outdoor temperature difference and air volume in real time, and adjusts the fan speed. The controller automatically switches between external circulation mode and internal circulation mode according to the CO2 concentration or the user-set threshold. The electronic control system integrates low temperature antifreeze and coil defrosting control programs.

[0016] A control method for an outdoor integrated fresh air conditioning unit with heat recovery is applied to an outdoor integrated fresh air conditioning unit with heat recovery. The controller of the electrical control system collects the indoor CO2 concentration, indoor and outdoor temperature difference and air volume in the duct in real time, and automatically switches between external circulation mode and internal circulation mode according to the CO2 concentration or user-set threshold. The external circulation mode includes the following steps: S101: Controls the opening of the second and fourth air valves, and controls the closing of the first and third air valves; S102: Start the fresh air fan and return air fan, forming independent exhaust and fresh air ducts inside the housing; Exhaust air duct airflow path: Indoor return air enters through the return air inlet, passes through the return air fan and the fourth air valve, and is sent to the exhaust side of the heat recovery device for heat exchange, then flows through the external coil, and is finally discharged to the outside through the exhaust outlet; Fresh air duct airflow path: Outdoor fresh air enters through the fresh air inlet, passes through the fresh air fan and the second air valve, and is sent to the fresh air side of the heat recovery device for pre-heat exchange, then flows through the internal coil for secondary temperature regulation, and the treated fresh air is sent into the room through the air supply outlet; S103: Controls the operating status of the external independent variable frequency compressor unit according to seasonal operating conditions, including the following conditions: Summer cooling mode: The external independent inverter compressor works, the internal coil acts as an evaporator to cool and dehumidify the fresh air, the external coil acts as a condenser to dissipate heat to the outside, and the heat recovery device lowers the temperature of the fresh air in advance to reduce the cooling load of the compressor. Winter heating mode: The four-way valve of the external independent variable frequency compressor reverses, the inner coil switches to the condenser to heat the fresh air, and the outer coil switches to the evaporator to absorb heat from the exhaust side. Transitional season ventilation mode: The external independent variable frequency compressor unit is shut down, and only the fresh air fan and return air fan are running, consuming only the fan power to achieve zero compression energy consumption for fresh air exchange; The inner loop mode includes the following steps: S201: Controls the second and fourth air valves to close, and controls the first and third air valves to open; S202: Cut off the airflow path to the heat recovery device, start the fresh air fan and return air fan to form an indoor closed-loop circulation duct and an outdoor heat dissipation duct; the external independent variable frequency compressor unit is in operation. The airflow path of the indoor closed-loop circulation duct is as follows: indoor return air enters through the return air inlet, passes through the return air fan and the third air valve, and is directly introduced into the indoor coil to complete heat exchange and temperature regulation. The temperature-regulated air is then sent back to the room through the air outlet. The airflow path of the outdoor heat dissipation duct is as follows: outdoor air enters through the fresh air inlet, passes through the fresh air fan and the first air valve, and is introduced into the outdoor coil to remove the heat from the coil. Then it is discharged outdoors through the exhaust outlet. The fresh air fan is reused as an air conditioning condenser fan to continuously dissipate heat for the outdoor coil, and there is no need to configure a separate dedicated condenser fan.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Heat pipe heat recovery achieves physical isolation between fresh and exhaust air, eliminating cross-contamination: The heat recovery device, fresh air, and exhaust airflow are completely separated by a metal partition. Compared with traditional paper heat exchange cores, there is no problem of water vapor exchange or odor mixing. Mold is not easy to grow in humid environments, and there is no risk of freezing and blockage at low temperatures. Hygiene and service life are greatly improved. Four-valve switching dual-duct topology, greatly improving the integration of the whole unit: a single outdoor unit relies on four sets of air valves to switch between two independent ducts. One unit has the dual functions of heat pipe heat recovery fresh air unit and household air conditioner heat exchange unit, eliminating the need for two sets of equipment to be assembled separately, reducing the amount of equipment procurement and on-site installation work. The air vents are arranged opposite each other on the left and right sides to completely solve the problem of thermal short circuit in the outdoor unit: the fresh air inlet and the exhaust air outlet are located at the left and right ends of the cabinet respectively. The solid structure of the cabinet isolates the hot and cold airflows, prevents the high-temperature exhaust air from being sucked into the fresh air inlet, reduces the condensation temperature, and improves the overall operating efficiency of the air conditioner. The fan reuse design simplifies the structure and reduces noise and failure rate: In external circulation mode, the fresh air fan is responsible for introducing outdoor fresh air, and in internal circulation mode, the fresh air fan is reused as the condenser cooling fan, eliminating the need for a separate condenser fan; reducing the number of parts in the whole machine, shrinking the size of the equipment, and reducing the overall operating noise and failure points; the matching EC fan can accurately steplessly adjust the speed, taking into account both energy saving and dynamic air volume matching; Multi-condition adaptability and all-season energy saving coverage: The working mode can be freely switched according to the outdoor seasonal temperature and indoor air quality: In extreme high and low temperature weather, the internal circulation mode is used to ensure constant temperature and low energy consumption; in the spring and autumn transition season, the compressor can be turned off and only heat recovery ventilation is performed; in daily ventilation mode, waste heat recovery is used to reduce the air conditioning load, adapting to all household scenarios. Modular and split structure, strong product adaptability: The air heat exchange box and the compressor unit are independent of each other, and different horsepower compressors can be matched according to the house area; the compressor unit can be disassembled and repaired separately without affecting the normal use of heat recovery, fans, air valves and other air handling units. Outdoor integrated layout, aesthetically pleasing installation without taking up indoor space: The entire unit is integrated and placed outdoors, with only short supply and return air ducts reserved indoors. There are no wall-mounted units or large indoor equipment, making it suitable for various decoration scenarios such as home decoration ceilings and small apartments, with a wide range of market applications. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an outdoor integrated fresh air conditioning unit with heat recovery.

[0019] Among them, 100 is the enclosure, 1 is the fresh air inlet, 2 is the air supply outlet, 3 is the return air outlet, 4 is the exhaust outlet, 5 is the inner coil, 6 is the outer coil, 7 is the fresh air fan, 8 is the return air fan, 9 is the first air valve, 10 is the second air valve, 11 is the third air valve, 12 is the fourth air valve, 13 is the heat recovery device, 14 is the first condensate pan, and 15 is the second condensate pan. Detailed Implementation

[0020] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0021] Please see Figure 1 The embodiments of the present invention include: An outdoor integrated fresh air conditioning unit with heat recovery is provided. The outdoor integrated fresh air conditioning unit with heat recovery includes a housing 100, which is assembled by welding of sealed sheet metal. The entire unit is placed on the ground or mounted in the outdoor area. Only the supply air and return air connection pipes are pre-embedded indoors, and there are no large indoor equipment.

[0022] The housing 100 has a fresh air inlet 1, a supply air inlet 2, a return air inlet 3, and an exhaust air inlet 4. The fresh air inlet 1 and the exhaust air inlet 4 are symmetrically distributed on the outer side of the housing 100, using the width of the housing 100 itself to separate the fresh air flow and exhaust air flow, eliminating thermal short circuits at the structural source. The supply air inlet 2 and the return air inlet 3 are located at the top of the housing 100. The supply air inlet 2 connects to the indoor supply air duct, and the return air inlet 3 connects to the indoor return air duct. Inside the housing 100, the fresh air inlet 1 and the exhaust air inlet 4 are physically separated by a metal partition. A first air valve 9 is installed below the partition. The housing 100 is divided into left and right chambers by the middle vertical metal partition. A heat recovery device 13 is arranged horizontally in the middle. The heat recovery device 13 serves as a shared heat exchange substrate for the fresh air duct and the exhaust air duct. Above the heat recovery device 13, there are air valves that separate the upper and lower chambers of the box 100. These include a second air valve 10 that separates the fresh air inlet 1 and the supply air outlet 2, and a fourth air valve 12 that separates the return air outlet 3 and the exhaust air outlet 4. Above the partition, there is a third air valve 11 that separates the upper chamber of the box 100. The first air valve 9, the second air valve 10, the third air valve 11, and the fourth air valve 12 form an air valve assembly. Each chamber of the box 100 switches between two completely independent air duct topologies by different opening and closing combinations of the air valves.

[0023] The lower right chamber of the housing 100 is equipped with a fresh air fan 7, the upper right chamber of the housing 100 above the fresh air fan 7 is equipped with an inner coil 5, the upper left chamber of the housing 100 is equipped with a return air fan 8, and the lower left chamber of the housing 100 below the return air fan 8 is equipped with an outer coil 6. The housing 100 serves as an air heat exchange unit and does not have a built-in compressor. The air conditioning compression cycle system is equipped with an external independent variable frequency compressor. The main unit of the variable frequency compressor integrates a four-way valve, a liquid receiver, a throttling element, and other refrigeration components. The main unit is installed outdoors nearby and is connected to the inner coil 5 and the outer coil 6 inside the housing 100 through refrigerant copper pipes to form a complete cooling / heating cycle. The modular and split design allows for universal matching of standard compressor main units, and the equipment can be flexibly maintained and adapted to different horsepower. The inner coil 5, the outer coil 6, the variable frequency compressor, and the four-way valve constitute the air conditioning compression cycle system. The air conditioning refrigerant with added refrigeration oil flows inside the pipes and is responsible for regulating the overall cooling and heating temperature of the room.

[0024] The housing 100 is provided with a first condensate pan 14 and a second condensate pan 15. The two sets of condensate pans are respectively located below the inner coil 5 and the outer coil 6, and receive the condensate generated by heat exchange.

[0025] The fresh air fan 7 and return air fan 8 are EC volute-less insert fans. The EC volute-less insert fans have their own drive circuit board, which can directly receive the speed regulation signal from the controller to realize independent stepless speed regulation of the fan; or the fresh air fan 7 and return air fan 8 are AC fans and equipped with an external frequency converter speed regulation device to realize speed regulation.

[0026] The outer side of the enclosure 100 is coated with a thermal insulation and waterproof coating. The fan drive circuit board and electrical control components are centrally arranged in an independent sealed moisture-proof chamber. The bottom of the enclosure 100 is integrated with a condensate tray and an external drain outlet, making it suitable for harsh operating environments such as outdoor sun exposure, rain, and low temperatures.

[0027] The heat recovery device 13 adopts a partition-type gravity heat pipe structure, which is filled with a low-boiling-point heat exchange medium. The air ducts are completely isolated by metal partitions, and there is no airflow communication channel.

[0028] The air valve adopts a low-leakage electric sealed air valve. The air valve blade is covered with an EPDM EPDM rubber sealing layer. The 100mm joint between the air valve body and the housing is filled with an EPDM foam sealing gasket. The overall air duct has a low air leakage rate and effectively prevents air from passing through the air duct.

[0029] A primary filter is installed inside the fresh air inlet 1, and an insect screen is installed on the outside of the exhaust outlet 4. Gravity check valves are installed at the external duct positions of the supply air outlet 2 and return air outlet 3. The check valves automatically close when the unit is stopped to prevent outdoor mosquitoes, odors, and hot or cold air from flowing back into the room.

[0030] The enclosure 100 has a built-in electronic control system. The controller of the electronic control system collects the indoor CO2 concentration, indoor and outdoor temperature difference, and air volume in the duct in real time, and adjusts the speed of the fresh air fan 7 and return air fan 8 to ensure that the fresh air and exhaust air volumes on both sides of the heat recovery device 13 are balanced and maximize the heat recovery efficiency. The controller automatically switches between external circulation mode and internal circulation mode according to the CO2 concentration or the threshold set by the user. The electronic control system integrates low temperature antifreeze and coil defrosting control programs to avoid frost on the heat pipe fins and the surface of the external coil, which would cause air duct blockage.

[0031] A control method for an outdoor integrated fresh air conditioning unit with heat recovery is provided. The controller of the electrical control system collects the indoor CO2 concentration, indoor-outdoor temperature difference, and airflow in the duct in real time. Based on the CO2 concentration or a user-set threshold, it automatically switches between external circulation mode and internal circulation mode.

[0032] External circulation mode (fresh air + heat recovery energy-saving mode) includes the following steps: S101: Control the second air valve 10 and the fourth air valve 12 to open, and control the first air valve 9 and the third air valve 11 to close; S102: Start the fresh air fan 7 and return air fan 8; the interior of the housing 100 forms independent exhaust air ducts and fresh air ducts; exhaust air duct airflow path: indoor return air enters through return air inlet 3, passes through return air fan 8 and fourth air valve 12 and is sent to the exhaust side of heat recovery device 13 for heat exchange, then flows through external coil 6, and finally is discharged to the outside through exhaust outlet 4; fresh air duct airflow path: outdoor fresh air enters through fresh air inlet 1, passes through fresh air fan 7 and second air valve 10 and is sent to the fresh air side of heat recovery device 13 for pre-heat exchange, then flows through internal coil 5 for secondary temperature adjustment, and the treated fresh air is sent into the room through air outlet 2; S103: Controls the operating status of the external independent variable frequency compressor unit according to seasonal operating conditions, including the following conditions: Summer cooling mode: The external independent inverter compressor works, the inner coil 5 acts as an evaporator to cool and dehumidify the fresh air, the outer coil 6 acts as a condenser to dissipate heat to the outside, and the heat recovery device 13 lowers the temperature of the fresh air in advance, effectively reducing the compressor's cooling load and reducing power consumption. Winter heating mode: The four-way valve of the external independent variable frequency compressor reverses, the inner coil 5 switches to the condenser to heat the fresh air, and the outer coil 6 switches to the evaporator to absorb heat from the exhaust side. Transitional season ventilation conditions: The external independent variable frequency compressor unit is shut down, and only the fresh air fan 7 and return air fan 8 are running, consuming only the fan power, to achieve zero compression energy consumption for fresh air exchange; The internal circulation mode (pure household air conditioning mode, no fresh air intake) includes the following steps: S201: Control the second air valve 10 and the fourth air valve 12 to close, and control the first air valve 9 and the third air valve 11 to open; S202: Cut off the airflow path to the heat recovery device 13, start the fresh air fan 7 and return air fan 8 to form an indoor closed-loop circulation duct and an outdoor heat dissipation duct; the external independent variable frequency compressor unit is in operation. The airflow path of the indoor closed-loop circulation duct is as follows: indoor return air enters through the return air inlet 3, passes through the return air fan 8 and the third air valve 11 and is directly introduced into the inner coil 5 to complete heat exchange and temperature regulation. The temperature-regulated air is then sent back to the room through the air outlet 2. The airflow path of the outdoor heat dissipation duct is as follows: outdoor air enters through the fresh air inlet 1, passes through the fresh air fan 7 and the first air valve 9 and is introduced into the outer coil 6 to remove the heat from the coil. Then it is discharged to the outside through the exhaust outlet 4. The fresh air fan 7 is reused as an air conditioning condenser fan to continuously dissipate heat for the outer coil 6. There is no need to configure a separate dedicated condenser fan.

[0033] This invention discloses an outdoor integrated fresh air conditioning unit with heat recovery, which can freely switch between pure air conditioning internal circulation mode and heat pipe energy-saving fresh air external circulation mode. It also takes into account the functions of air conditioning temperature regulation, fresh air exchange, and exhaust waste heat recovery, and has the advantages of low energy consumption, stable operation and good hygiene.

[0034] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An outdoor integrated fresh air conditioning unit with heat recovery, characterized in that: The enclosure (100) is located outdoors. The enclosure (100) has fresh air inlets (1) and exhaust outlets (4) symmetrically distributed on the left and right sides. The top of the enclosure (100) has air supply outlets (2) and return air outlets (3) that are connected to indoor pipes respectively. The interior of the enclosure (100) is divided into four chambers: upper left, lower left, upper right, and lower right by a damper assembly. Each chamber switches between two completely independent air duct topologies by different opening and closing combinations of dampers. A heat recovery device (13) is arranged horizontally in the middle of the enclosure (100). A fresh air fan (7) is arranged in the lower right chamber of the enclosure (100). An inner coil (5) is arranged in the upper right chamber of the enclosure (100) above the fresh air fan (7). A return air fan (8) is arranged in the upper left chamber of the enclosure (100). An outer coil (6) is arranged in the lower left chamber of the enclosure (100) below the return air fan (8). The housing (100) serves as an air heat exchange unit. It does not have a built-in compressor unit but is connected to an independent variable frequency compressor. The main unit of the variable frequency compressor integrates a four-way valve, a liquid receiver, and a throttling element. The refrigeration components are connected to the inner coil (5) and the outer coil (6) respectively through refrigerant copper pipes to form a complete refrigeration / heating cycle.

2. The outdoor integrated fresh air conditioning unit with heat recovery according to claim 1, characterized in that: The fresh air fan (7) and return air fan (8) are selected as EC volute-less insertion fans or AC fans.

3. The outdoor integrated fresh air conditioning unit with heat recovery according to claim 1, characterized in that: The air valve assembly includes a first air valve (9) installed on the lower part of the vertical partition inside the housing (100), a third air valve (11) installed on the upper part of the partition, a second air valve (10) placed horizontally in the middle of the housing (100) to separate the fresh air inlet (1) and the air supply outlet (2), and a fourth air valve (12) to separate the return air outlet (3) and the exhaust air outlet (4).

4. An outdoor integrated fresh air conditioning unit with heat recovery according to claim 3, characterized in that: The air valve adopts a low-leakage electric sealed air valve, the air valve blade is covered with a rubber sealing layer, and the joint between the air valve body and the box (100) is filled with a foam sealing gasket.

5. An outdoor integrated fresh air conditioning unit with heat recovery according to claim 1, characterized in that: The heat recovery device (13) adopts a partition-type gravity heat pipe structure and is filled with a low-boiling-point heat exchange medium.

6. An outdoor integrated fresh air conditioning unit with heat recovery according to claim 1, characterized in that: A primary filter is installed inside the fresh air inlet (1), and an insect screen is installed outside the exhaust outlet (4); gravity check valves are installed at the external duct positions of the supply air outlet (2) and return air outlet (3).

7. An outdoor integrated fresh air conditioning unit with heat recovery according to claim 1, characterized in that: The outer side of the box (100) is coated with a heat-insulating and waterproof coating. The fan drive circuit board and electrical control components are centrally arranged in an independent sealed moisture-proof chamber. The bottom of the box (100) is integrated with a condensate tray and an external drain outlet.

8. An outdoor integrated fresh air conditioning unit with heat recovery according to claim 1, characterized in that: The enclosure (100) has a built-in electronic control system. The controller of the electronic control system collects the indoor CO2 concentration, indoor and outdoor temperature difference and air volume of the air duct in real time, and adjusts the speed of the fan. The controller automatically switches between external circulation mode and internal circulation mode according to the CO2 concentration or the threshold set by the user. The electrical control system integrates low-temperature antifreeze and coil defrosting control programs.

9. A control method for an outdoor integrated fresh air conditioning unit with heat recovery, applied to an outdoor integrated fresh air conditioning unit with heat recovery as described in any one of claims 1-8, characterized in that: The controller of the electronic control system collects indoor CO2 concentration, indoor-outdoor temperature difference and air volume in real time, and automatically switches between external circulation mode and internal circulation mode according to CO2 concentration or user-set threshold. The external circulation mode includes the following steps: S101: Control the second air valve (10) and the fourth air valve (12) to open, and control the first air valve (9) and the third air valve (11) to close; S102: Start the fresh air fan (7) and return air fan (8), and the exhaust air duct and fresh air duct are formed inside the box (100); the airflow path of the exhaust air duct: the indoor return air enters through the return air inlet (3), and is sent to the exhaust side of the heat recovery device (13) through the return air fan (8) and the fourth air valve (12) for heat exchange, and then flows through the outer coil (6), and finally is discharged to the outside through the exhaust port (4); the airflow path of the fresh air duct: the outdoor fresh air enters through the fresh air inlet (1), and is sent to the fresh air side of the heat recovery device (13) through the fresh air fan (7) and the second air valve (10) for pre-heat exchange, and then flows through the inner coil (5) for secondary temperature adjustment, and the treated fresh air is sent into the room through the air supply port (2); S103: Controls the operating status of the external independent variable frequency compressor unit according to seasonal operating conditions, including the following conditions: Summer cooling operation: The external independent variable frequency compressor works, the inner coil (5) acts as an evaporator to cool and dehumidify the fresh air, the outer coil (6) acts as a condenser to dissipate heat to the outside, and the heat recovery device (13) lowers the temperature of the fresh air in advance to reduce the cooling load of the compressor. Winter heating mode: The four-way valve of the external independent variable frequency compressor is switched, the inner coil (5) is switched to the condenser to heat the fresh air, and the outer coil (6) is switched to the evaporator to absorb the heat from the exhaust side. Transitional season ventilation conditions: The external independent variable frequency compressor host is shut down, and only the fresh air fan (7) and return air fan (8) are running, consuming only the fan power, to achieve zero compression energy consumption for fresh air exchange; The inner loop mode includes the following steps: S201: Control the second air valve (10) and the fourth air valve (12) to close, and control the first air valve (9) and the third air valve (11) to open; S202: Cut off the airflow path to the heat recovery device (13), start the fresh air fan (7) and return air fan (8) to form an indoor closed-loop circulation air duct and an outdoor heat dissipation air duct; the external independent variable frequency compressor host is running, the airflow path of the indoor closed-loop circulation air duct: the indoor return air enters through the return air inlet (3), passes through the return air fan (8) and the third air valve (11) and is directly introduced into the inner coil (5) to complete heat exchange and temperature adjustment, and the temperature-adjusted air is sent back to the room through the air outlet (2); the airflow path of the outdoor heat dissipation air duct: the outdoor air enters through the fresh air inlet (1), passes through the fresh air fan (7) and the first air valve (9) and is introduced into the outer coil (6) to take away the heat of the coil, and then is discharged to the outside through the exhaust outlet (4); the fresh air fan (7) is reused as an air conditioning condenser heat dissipation fan to continuously dissipate heat for the outer coil (6), and there is no need to configure a separate dedicated condenser fan.

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