Fresh air device

Abstract

A fresh air device comprises an air inlet unit and an outdoor unit. The air inlet unit sequentially comprises a fresh air primary filtering section, a heat pipe circulation recovery front section, a primary air return system, a surface cooling section, an evaporation section, a heat pipe circulation recovery rear section, a secondary air return system, a condensation heat recovery section and a reheating coil section from the fresh air inlet end to the fresh air outlet end. The primary air return system comprises a primary air return section and a primary air return pipe communicated with the primary air return section, the secondary air return system comprises a secondary air return section and a secondary air return pipe communicated with the secondary air return section, and an air supply fan is further arranged in the secondary air return section. An electronic adjusting three-way valve is arranged in the outdoor unit to adjust the flow direction of the high-pressure refrigerant, and a refrigerant medium-pressure section is arranged to communicate with the inlet end of the evaporation section. The fresh air temperature and humidity are rapidly and stably adjusted while the energy consumption of the fresh air device is reduced, and the stability of the indoor temperature and humidity is maintained.

Description

Technical Field

[0001] The present application relates to the field of air treatment technology, and in particular to a fresh air device. Background Art

[0002] Air conditioning systems are designed to provide a controlled, comfortable, and healthy air environment for indoor activities or to provide specific air conditions for activities such as warehousing, processing, and equipment operation. Air conditioning primarily involves controlling air quality, temperature, humidity, and wind speed.

[0003] A relatively natural and effective method for controlling air quality is to replace or dilute indoor air with fresh air from outside, maintaining the indoor oxygen content within a reasonable range and creating a very comfortable and clean environment. This involves drawing in some fresh air from outside and expelling some indoor air. Existing fresh air systems cannot quickly adjust the fresh air temperature and humidity when the indoor temperature and humidity differ significantly from the preset temperature and humidity, or when the outdoor fresh air temperature and humidity differ significantly from the preset temperature and humidity. For example, in the summer, when the fresh air is hot and humid, it cannot be quickly cooled and dehumidified, and can easily cause ice to form on the evaporator, affecting the normal operation of the fresh air system. In the winter, when the outdoor fresh air is cold and low in humidity, it cannot quickly increase the fresh air temperature. Furthermore, existing fresh air systems use a separate cold source to condense and dehumidify the moisture in the fresh air, and then separately reheat the dehumidified fresh air with electrical heating or other methods to meet air supply conditions. This approach results in high energy consumption, large temperature and humidity fluctuations, and poor indoor temperature stability. Therefore, reducing the energy consumption of fresh air systems while quickly and stably adjusting the fresh air temperature and humidity to maintain stable indoor air temperature and humidity is a technical challenge that needs to be addressed. Utility Model Content

[0004] In order to solve the technical problems of high energy consumption and inability to quickly and stably adjust the temperature and humidity of fresh air in existing fresh air devices, the present application provides a fresh air device, including an air intake unit and an outdoor unit, wherein the air intake unit includes, from the fresh air inlet end to the fresh air outlet end, a fresh air primary filtration section, a heat pipe circulation recovery front section, a primary return air system, a surface cooling section, an evaporation section, a heat pipe circulation recovery rear section, a secondary return air system, a condensation heat recovery section and a reheat coil section, wherein the heat pipe circulation recovery front section and the heat pipe circulation recovery rear section form a closed loop to recycle the sensible heat of the fresh air; the primary return air system includes a primary return air section and a primary return air duct connected to the primary return air section to introduce indoor return air and outdoor fresh air for a single mixing; the secondary return air system includes a secondary return air section and a secondary return air duct connected to the secondary return air section to introduce indoor return air and outdoor fresh air for a single mixing A secondary return air duct for secondary mixing of internal return air and outdoor fresh air, wherein an air supply fan is provided in the secondary return air section; the outdoor unit includes a compressor, a condenser, a refrigerant low-pressure section connected to the compressor, a refrigerant medium-pressure section and a refrigerant high-pressure section, an electronic regulating three-way valve is provided in the outdoor unit, the inlet end of the electronic regulating three-way valve is connected to the compressor to receive the high-pressure refrigerant compressed by the compressor, the first outlet end of the electronic regulating three-way valve is connected to the inlet end of the condensation heat recovery section via the refrigerant high-pressure section, and the second outlet end of the electronic regulating three-way valve is connected to the refrigerant medium-pressure section via the condenser; the inlet end of the evaporation section is provided with a pressure reducing device and is connected to the outlet end of the condensation heat recovery section and the refrigerant medium-pressure section, and the outlet end of the evaporation section is connected to the refrigerant low-pressure section.

[0005] According to the above technical solution, by placing the primary return air system and the secondary return air system before and after the evaporation section and the surface cooling section in the air intake unit, respectively, the indoor primary return air is mixed with the fresh air and passes through the surface cooling section and the evaporation section. As a result, in summer, more air can pass through the evaporation section and / or the surface cooling section to remove the coldness, quickly and stably adjust the temperature and humidity of the fresh air and avoid freezing of the evaporation section, thereby maintaining the normal operation of the fresh air device. In winter, more air can pass through the surface cooling section to remove the heat of the surface cooling section, quickly raising the fresh air temperature and thus quickly maintaining the stability of the indoor temperature. At the same time, the sensible heat of the outdoor fresh air and the heat released when the compressor compresses the refrigerant are recycled and utilized. The medium-pressure section of the outdoor refrigerant is connected to the inlet end of the evaporation section in the air intake unit to further utilize the refrigerant decompression to absorb heat to achieve better cooling and dehumidification effects, further reducing energy consumption.

[0006] In some embodiments, a medium efficiency filter is further provided in the secondary return air section. By providing the medium efficiency filter in the secondary return air section, the return air can be filtered and the resistance of the secondary return air can be increased to balance the resistance difference between the primary return air and the secondary return air.

[0007] In certain embodiments, the evaporation section includes an evaporation coil, and a drying filter is further provided at the inlet end of the evaporation coil.

[0008] In certain embodiments, the air intake unit further includes a medium-efficiency filter section positioned after the secondary return air section and before the condensation heat recovery section. By positioning the medium-efficiency filter section after the secondary return air section and before the condensation heat recovery section, the supply air blower in the secondary return air section can blow air toward the medium-efficiency filter section using positive pressure, easily overcoming resistance in the medium-efficiency filter section, reducing fan power consumption, and maintaining stable wind speed.

[0009] In certain embodiments, the fresh air device also includes an automatic control system, which includes a central controller and a compressor frequency controller, a temperature and humidity preset module, a temperature and humidity sensor arranged at the fresh air inlet, temperature and humidity sensors installed at the primary return air inlet and the secondary return air inlet, and a switch controller arranged at each section, and the central controller is used to compare the temperature and humidity range preset by the temperature and humidity preset module with the temperature and humidity values ​​read by the temperature and humidity sensor at the fresh air inlet and the temperature and humidity sensors at the primary return air inlet and the secondary return air inlet, and automatically adjust the return air ratio of the primary return air and the secondary return air and the working status of each other section. According to the above implementation plan, the indoor temperature and humidity range is preset through the automatic control system, and the return air ratio of the primary return air and the secondary return air is dynamically adjusted according to the indoor and outdoor temperature and humidity ranges, so as to further quickly and stably adjust the fresh air temperature and humidity, and better maintain the stability of the indoor temperature and humidity, thereby overcoming the problems of high energy consumption, large temperature and humidity fluctuations, and poor stability caused by the fixed return air ratio in the existing fresh air device using return air. In addition, the working status of each section is dynamically adjusted according to the indoor and outdoor temperature and humidity ranges, so that the fresh air device can fully utilize the processing advantages of each section, and more reasonably recycle and utilize the sensible heat of indoor and outdoor exhaust gas and outdoor fresh air, as well as the heat released when the compressor compresses the refrigerant. As long as the fresh air temperature and humidity are within the set range, there is no need to adjust the return air ratio and the working status of each section, so that the entire unit always operates in a constant cold and hot state, thereby maximizing the reduction of energy consumption and extending the service life of the equipment.

[0010] In certain embodiments, the switch controller provided in each section further includes a primary return air proportional regulating valve provided in the primary return air duct and a secondary return air proportional regulating valve provided in the secondary return air duct, a proportional electric valve provided on the surface cooling section, and a control switch provided on the reheat coil section.

[0011] In certain embodiments, the air intake unit further includes a humidification section arranged after the reheat coil section, and the switch controller arranged on each section further includes a control switch arranged on the humidification section and connected to the central controller.

[0012] In certain embodiments, the air intake unit further includes a high-efficiency filter section disposed at the fresh air outlet end for further filtering dust particles in the mixed fresh air.

[0013] In certain embodiments, the preset temperature range is 19-24° C., and the preset humidity range is 40%-65%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present application will be further described below with reference to the accompanying drawings and examples. In the accompanying drawings:

[0015] Figure 1 Schematic diagram of the structure of the fresh air device;

[0016] Figure 2 This is a detailed structural cross-sectional diagram of the fresh air device;

[0017] Figure 3 This is a cross-sectional view of the external unit structure of the fresh air device.

[0018] Description of reference numerals:

[0019] 10 Air intake unit; 11 Fresh air primary filtration section; 12 Heat pipe recycling front section; 121 Heat pipe recycling front section coil; 13 Primary return air system; 131 Primary return air ratio control valve; 14 Surface cooling section; 141 Surface cooling coil; 15 Evaporation section; 151 Drying filter; 152 Electronic pressure reducing valve; 153 Evaporation coil; 16 Heat pipe recycling rear section; 161 Heat pipe recycling rear section coil; 17 Secondary return air system; 171 Supply air fan; 172 Medium efficiency filter; 173 Secondary return air ratio control valve; 18 Medium efficiency filtration section; 19 Condensation heat recovery section; 191 Condensation heat recovery section coil; 20 Reheat coil section; 21 Humidification section; 30 External unit; 31 Compressor; 32 Refrigerant low-pressure section; 33 Refrigerant high-pressure section; 331 Electronic regulating three-way valve; 34 Refrigerant medium-pressure section; 35 Condenser. DETAILED DESCRIPTION

[0020] The technical solution of the present application will be described in detail below with reference to the accompanying drawings and embodiments, but the present application is not limited to the scope of the embodiments.

[0021] The key concept of the present application is to provide a fresh air device, which optimizes the arrangement order of the functional sections of the air intake unit, and arranges the primary return air system and the secondary return air system before and after the evaporation section and the surface cooling section respectively, so that the indoor primary return air is mixed with the fresh air and passes through the surface cooling section and the evaporation section. A refrigerant medium-pressure section is arranged in the outdoor unit to connect to the inlet end of the evaporation section in the air intake unit, so as to make full use of the sensible heat of the indoor return air and the outdoor fresh air and the energy generated in the compression and decompression process of the refrigerant, so as to realize rapid adjustment of the fresh air temperature and humidity on the basis of energy saving, maintain the stability of the indoor temperature and humidity, and eliminate the hot and cold phenomenon in the fresh air treatment process of the fresh air device.

[0022] like Figure 1 and Figure 2 As shown, the air intake unit 10 of the fresh air device includes, from the fresh air inlet end to the fresh air outlet end, a fresh air primary filter section 11, a heat pipe circulation recovery front section 12, a primary return air system 13, a surface cooling section 14, an evaporation section 15, a heat pipe circulation recovery rear section 16, a secondary return air system 17, a medium-efficiency filter section 18, a condensation heat recovery section 19, a reheat coil section 20 and a humidification section 21, wherein the heat pipe circulation recovery front section 12 and the heat pipe circulation recovery rear section 16 form a closed loop to recycle the sensible heat of the fresh air.

[0023] The fresh air primary filter section 11 is used to perform preliminary filtration on the fresh air. The heat pipe circulation recovery front section 12 includes a heat pipe circulation recovery front section coil 121, and the heat pipe circulation recovery rear section 16 includes a heat pipe circulation recovery rear section coil 161. The heat pipe circulation recovery front section coil 121 and the heat pipe circulation recovery rear section coil 161 are filled with a refrigerant, and the heat pipe circulation recovery rear section 16 and the heat pipe circulation recovery front section 12 operate in a closed loop. A refrigerant circulation pump is provided on the pipeline connecting the heat pipe circulation recovery front section 12 and the heat pipe circulation recovery rear section 16. The cold recovered by the heat pipe circulation recovery rear section 16 is transported to the heat pipe circulation recovery front section 12 via the refrigerant and the refrigerant circulation pump for cooling the fresh air. At the same time, the heat of the outdoor fresh air recovered by the heat pipe circulation recovery front section 12 is brought into the heat pipe circulation recovery rear section 16 for heating and raising the temperature of the mixed fresh air.

[0024] The primary return air system 13 includes a primary return air section and a primary return air duct connected to the primary return air section to introduce indoor return air and outdoor fresh air for primary mixing. The indoor return air and fresh air are mixed in the primary return air section. By mixing the indoor primary return air with fresh air before the evaporation section and the surface cooling section, more air volume passes through the evaporation section and the surface cooling section. This can quickly remove the cooling energy from the evaporation section and / or the surface cooling section in the summer, while simultaneously performing deep dehumidification and removing the generated humidity indoors, thus ensuring stable indoor humidity. In the winter, the heat from the surface cooling section is quickly removed, rapidly increasing the fresh air temperature and thus quickly maintaining a stable indoor temperature.

[0025] The secondary return air system 17 includes a secondary return air section and a secondary return air duct connected to the secondary return air section to introduce indoor return air and outdoor fresh air for secondary mixing. The secondary return air section is equipped with a supply air blower 171. The secondary mixed fresh air is blown to the rear section by the supply air blower 171. The secondary return air helps to increase the temperature of the mixed fresh air.

[0026] like Figure 2 As shown, the secondary return air section is further provided with a medium efficiency filter 172. The medium efficiency filter 172 increases the secondary return air resistance to balance the resistance difference between the primary return air and the secondary return air, and on the other hand filters the return air.

[0027] like Figure 3 As shown, the outdoor unit 30 includes a compressor 31, a condenser 35, a low-pressure refrigerant section 32, a medium-pressure refrigerant section 34, and a high-pressure refrigerant section 33, all of which are connected to the compressor 31. An electronically adjustable three-way valve 331 is also provided within the outdoor unit 30. The inlet of the electronically adjustable three-way valve 331 is connected to the compressor 31 to receive the high-pressure refrigerant compressed by the compressor 31. The first outlet of the electronically adjustable three-way valve 331 is connected to the inlet of the condensation heat recovery section 19 via the high-pressure refrigerant section 33. The second outlet of the electronically adjustable three-way valve 331 is connected to the medium-pressure refrigerant section 34 via the condenser 35. The medium-pressure refrigerant section 34 is connected to the inlet of the evaporation section 15. There is a condenser coil in the condenser 35. By controlling the electronic regulating three-way valve 331, the high-pressure refrigerant compressed by the compressor can flow into the condensation heat recovery section 19 through the refrigerant high-pressure section 33 to heat the fresh air, or release the condensation heat through the external unit condenser 35, and the high-pressure refrigerant becomes a medium-pressure refrigerant, and then flows into the evaporation section 15 through the inlet end of the evaporation section 15 to cool and dehumidify the fresh air.

[0028] An evaporation coil 153 is installed in the evaporation section 15. A drying filter 151 is also provided at the inlet end of the evaporation coil 153, and an electronic pressure reducing valve 152 is provided at the outlet end of the drying filter 151. The inlet end of the evaporation section 15 is connected to the outlet end of the condensation heat recovery section 19 and the refrigerant medium-pressure section 34, and the outlet end of the evaporation section 15 is connected to the refrigerant low-pressure section 32. The dehumidification capacity of the evaporation section 15 is adjusted according to the humidity of the fresh air to ensure that the humidity is controlled within the optimal range. When the humidity of the fresh air after a single mixing is close to the maximum point of the preset humidity range of 65%, the temperature of the mixed fresh air passing through the evaporation section 15 is slowly increased to a point close to the maximum point of the preset temperature. When the temperature is high, dehumidification will reduce the power consumption of dehumidification and the power consumption of dehumidification will also be reduced. At this time, the compressor is kept running at minimum power consumption. When the humidity remains stable for a period of time, the compressor is stopped to ensure the dehumidification effect and reduce humidity fluctuations.

[0029] Condensation heat recovery section 19 houses a condensation heat recovery section coil 191. Its inlet connects to the high-pressure refrigerant section 33, while its outlet connects to the inlet of the evaporation coil 153. A check valve is installed at the outlet of condensation heat recovery section 191. An electronic proportional three-way valve 331 regulates the amount of high-pressure refrigerant flowing into condensation heat recovery section 19. High-pressure refrigerant from the compressor flows through the high-pressure refrigerant section 33 into condensation heat recovery section coil 191 in condensation heat recovery section 19, where it heats the fresh air and becomes medium-pressure refrigerant. The refrigerant then passes through the electronic pressure reducing valve 152 and flows through the inlet of the evaporation coil 153 into the evaporation section 15, where it evaporates and absorbs heat, lowering the temperature of the evaporation coil 153. Moisture in the high-humidity outdoor fresh air condenses upon contact with the cool evaporation coil 153, removing excess moisture from the air and thus achieving the effect of dehumidifying the fresh air.

[0030] When the medium-pressure refrigerant flowing out of the condensing heat recovery section 19 cannot meet the cooling and dehumidification requirements of the evaporating section 15, the second outlet of the electronic regulating three-way valve 331 is opened. At this time, the high-pressure refrigerant is converted into medium-pressure refrigerant after dissipating heat through the outdoor unit condenser 35. The medium-pressure refrigerant flows into the evaporating section 15 through the refrigerant medium-pressure section 34 to further evaporate, absorb heat, cool and dehumidify. The flow direction of the high-pressure refrigerant can be adjusted by setting the electronic regulating three-way valve 331. The high-pressure refrigerant can directly enter the condensing heat recovery section coil 191 to exchange heat with the fresh air and heat the fresh air, or the high-pressure refrigerant can pass through the outdoor unit condenser 35 to become medium-pressure refrigerant and enter the evaporating section to absorb heat and cool the fresh air. This makes the above-mentioned energy-saving fresh air device suitable for fresh air treatment in different environments.

[0031] A medium-efficiency filter is installed in the medium-efficiency filter section 18 for filtering the mixed fresh air. The secondary mixed fresh air filtered by the medium-efficiency filter section 18 undergoes heat exchange with the condensation heat recovery section coil 191 to heat the secondary mixed fresh air after cooling and dehumidification. When the secondary mixed fresh air does not need to be heated after passing through this section, the electronic proportional three-way valve 331 controls the high-pressure refrigerant to not pass through the condensation heat recovery section coil 191, but to directly discharge the condensation heat from the outdoor unit condenser 35 and become a medium-pressure refrigerant, which is used to exchange heat with the mixed fresh air in the evaporation section 15 for cooling and dehumidification, which is beneficial for the fresh air device to be suitable for fresh air treatment in different environments.

[0032] The fresh air device also includes an automatic control system, comprising a central controller for controlling the operation of each segment, a frequency controller for the compressor 31 connected to the central controller, a temperature and humidity preset module, a temperature and humidity sensor located at the fresh air inlet, temperature and humidity sensors installed at the primary and secondary return air inlets, and switch controllers located at each segment. The central controller compares the temperature and humidity ranges preset by the temperature and humidity preset module with the temperature and humidity values ​​read by the temperature and humidity sensors at the fresh air inlet, the primary and secondary return air inlets, and automatically adjusts the return air ratio between the primary and secondary return air, as well as the operating conditions of the other segments.

[0033] The switch controllers installed in each section further include a primary return air ratio control valve 131 in the primary return air duct, a secondary return air ratio control valve 173 in the secondary return air duct, a proportional electric valve on the surface cooling section 14, and a control switch on the reheat coil section 20. The primary return air ratio control valve 131 and the secondary return air ratio control valve 173 control the amount of return air entering the primary and secondary return air sections. By dynamically adjusting the return air ratio between the primary and secondary return air, the temperature and humidity of the fresh air can be more efficiently and effectively adjusted. When the outdoor fresh air temperature and humidity differ significantly from the indoor preset temperature and humidity range, or when the indoor temperature and humidity differ significantly from the preset temperature and humidity range, requiring rapid cooling or heating, the primary return air volume is appropriately increased by adjusting the primary return air ratio control valve 131. The primary return air volume can account for 70%-100% of the total return air volume, such as 80% or 90%, thereby increasing the primary mixed fresh air volume passing through the surface cooling section 14 and the evaporation section 15. This allows more of the primary mixed fresh air to remove the cooling energy or heat from the evaporation section and / or the surface cooling section, thereby achieving rapid cooling, dehumidification, or heating of the fresh air. The secondary return air system 17 can heat the mixed fresh air after cooling and dehumidification. Therefore, while the primary return air volume reaches the minimum requirement to meet the cooling and dehumidification requirements, it is ensured that as much return air as possible passes through the secondary return air section to increase the temperature of the primary mixed fresh air. When the indoor temperature and humidity are within the preset range or close to the preset range, and the outdoor fresh air temperature and humidity are slightly different from the indoor preset temperature and humidity range, the primary return air ratio regulating valve 131 and the secondary return air ratio regulating valve 173 can be adjusted to make the primary return air volume and the secondary return air volume equivalent, such as the primary return air volume accounts for 50%-60% of the total return air volume.

[0034] The fresh air after the primary mixing exchanges heat with the surface cooling coil 141 in the surface cooling section 14. The surface cooling coil 141 is connected to the cold (hot) source water system of the air conditioner, which plays a role in regulating the temperature of the fresh air and coordinating with dehumidification. When the temperature of the fresh air is high and the humidity is high, and the maximum cooling capacity of the evaporation section 15 is insufficient to reduce the temperature of the fresh air after the primary mixing to below the dew point, the surface cooling section 14 is activated to assist in cooling and dehumidification. When the humidity is within the set range but the temperature is too high, the evaporation section 15 is not activated and only the surface cooling section 14 is activated for cooling. The automatic control system also includes a proportional electric valve connected to the central controller and arranged on the surface cooling section 14, which is used to adjust the working state of the surface cooling section 14 according to the preset temperature and humidity range.

[0035] The reheat coil installed in the reheat coil section 20 is connected to the air conditioning hot water system and is used to heat the fresh air after secondary mixing. The reheating capacity of the reheat coil section 20 is much smaller than the power of the surface cooling section 14, and the adjustment accuracy is high. When the heating capacity of the reheat coil section 20 is insufficient, the surface cooling section 14 is used to heat and increase the temperature of the mixed fresh air. If the condensation heat of the condensation heat recovery section 19 is fully recovered and still cannot meet the supply air temperature, the reheat coil section 20 is turned on. The fresh air after secondary mixing enters the reheat coil section 20 and is heated to a preset temperature range. The automatic control system also includes a control switch provided on the reheat coil section 20 and connected to the central controller, which is used to adjust the working state of the reheat coil section 20 according to the preset temperature and humidity range.

[0036] A steam humidification nozzle is installed in the humidification section 21 for humidifying the secondary mixed fresh air. The automatic control system also includes a control switch connected to the central controller and arranged on the humidification section 21 for adjusting the working state of the humidification section 21 according to the preset temperature and humidity range.

[0037] In the above-mentioned fresh air device, the air inlet unit 10 further includes a high-efficiency filter section (not shown) arranged at the fresh air outlet end for further filtering the mixed fresh air. The mixed fresh air passes through the high-efficiency filter section and then enters the room through the air outlet section.

[0038] In the above-mentioned fresh air device, the temperature and humidity preset module presets a temperature range of 19-24°C and a humidity range of 40%-65%. Since the temperature and humidity of outdoor fresh air vary greatly in different regions and seasons, the automatic control system dynamically tracks the temperature and humidity by presetting the indoor temperature and humidity range. When the indoor temperature and humidity and the outdoor fresh air are within the temperature and humidity range, such as when the temperature and humidity in the transition season are mostly within the set range, no adjustment is required. When the temperature and humidity are not within the set range, the return air ratio in the primary return air section and the secondary return air section is adjusted while coordinating with the adjustment of other sections to maintain the temperature and humidity of the indoor air within the set range, thereby minimizing energy consumption.

[0039] Example 1 Treatment of low-temperature and low-humidity outdoor fresh air in winter

[0040] In winter, when the temperature and humidity of the outdoor fresh air fall below the lower limits of the preset temperature range of 19-24°C and humidity range of 40%-65%, the central controller shuts down the compressor 31 of the outdoor unit 30, thereby disabling the evaporation section 15 and the condensation heat recovery section 19. The central controller then gradually reduces the speed of the brine circulating pump, causing the brine in the heat pipe front-end recovery coil 121 and heat pipe rear-end recovery coil 161 to enter a static state.

[0041] After the outdoor fresh air is filtered by the fresh air primary filter section 11, it is mixed with the indoor primary return air in the primary return air section. At this time, the central controller controls the opening amplitude of the primary return air ratio regulating valve 131 according to the outdoor fresh air temperature, increases the return air volume in the primary return air section, and allows more primary mixed fresh air to be heated by the surface cooling section 14. At this time, the surface cooling coil 141 in the surface cooling section 14 is connected to the air-conditioning hot water system, and the air-conditioning hot water system heats the primary mixed fresh air passing through the surface cooling section 14 so that the primary mixed fresh air can be heated efficiently and quickly.

[0042] The reheat coil section 20 requires far less power than the surface cooling section 14 in winter, allowing for high regulation accuracy. When the reheat coil section 20's heating capacity is insufficient, the surface cooling section 14 provides additional heating, ultimately raising the fresh air temperature to a constant 19°C. Simultaneously, the humidification section 21 provides isothermal humidification, ensuring the humidification capacity is minimized at 19°C, thus minimizing energy consumption. When the outdoor fresh air temperature approaches the preset lower limit of 19°C, the heat from the reheat coil section 20 can bring the low-temperature mixed fresh air within the preset temperature range, and the surface cooling section 14 can be deactivated.

[0043] After primary mixing, fresh air is heated by the surface cooling section 14 and the secondary return air section before being filtered by the medium-efficiency filter section 18. It is then heated by the reheat coil section 20 and humidified by the humidification section 21 to reach the appropriate temperature and humidity. Afterwards, it is filtered by the high-efficiency filter section before being delivered to the room. The central controller regulates the operating status of each section to achieve the highest exchange efficiency within the preset temperature and humidity range, achieving energy savings of up to 30%.

[0044] Example 2 Treatment of high temperature and high humidity outdoor fresh air in summer

[0045] The preset temperature range is 19-24°C and the humidity range is 40%-65%. High-temperature, high-humidity outdoor fresh air is filtered through the fresh air primary filter section 11 at the front end of the fresh air device's air intake unit 10 before entering the heat pipe recovery section 12 for pre-cooling, reducing it to medium-temperature, high-humidity fresh air. The recovered heat is then transferred to the heat pipe recovery section 16 via the refrigerant and refrigerant circulation pump. The cooled fresh air is mixed with the indoor primary return air in the primary return air section before being cooled by the surface cooling section 14 and further cooled and dehumidified by the evaporation section 15. If the medium-pressure refrigerant flowing out of the condensation heat recovery section 19 cannot meet the cooling and dehumidification requirements of the evaporation section 15, the electronic three-way valve 331 is used to control the refrigerant from the medium-pressure section 34 to the evaporator coil 153 for additional cooling and dehumidification. If the preset dehumidification range is still not reached after all the cold in the refrigerant has been fully recovered, the surface cooling section 14 is activated for further cooling.

[0046] After cooling and dehumidifying in the evaporation section 15, the mixed fresh air is heated and heated in the heat pipe circulation recovery section 16 and then enters the secondary return air section 17 for secondary mixing and heating with the indoor return air. The ratio of the primary and secondary return air is adjusted by the primary return air ratio regulating valve 131 and the secondary return air ratio regulating valve 173. By increasing the primary return air volume, sufficient air volume can be provided for the next dehumidification step to ensure that the fresh air after the primary mixing can meet the dehumidification requirements under high humidity conditions and the evaporator surface in the evaporation section 15 is not frozen. While increasing the primary return air volume to meet the dehumidification needs, it is ensured that as much secondary return air as possible is mixed with the primary mixed fresh air after the heat pipe circulation recovery section 16 to further increase the temperature of the mixed fresh air.

[0047] If the air supply requirements are still not met after adjusting the primary and secondary return air volumes, the secondary mixed fresh air is filtered through the medium-efficiency filter section 18 and then sent to the condensation heat recovery section 19 for heating. If the condensation heat is fully recovered and still cannot meet the air supply requirements, the reheat coil section 20 connected to the air conditioning hot water system is activated to further heat the mixed fresh air, gradually raising the supply air temperature to a preset range. The air is then filtered through the high-efficiency filter section and sent indoors. In summer, the fresh air humidity is high, and the humidification section 21 basically does not operate. The energy saving rate of the fresh air device is as high as 70%.

[0048] Example 3 Treatment of outdoor high humidity fresh air at 36°C

[0049] The preset temperature range is 19-24°C and the humidity range is 40%-65%. The outdoor fresh air temperature detected by the fresh air inlet temperature sensor is 36°C, and the indoor temperature detected by the return air inlet temperature sensor is 23-25°C. At this time, the central controller outputs a corresponding control signal and opens the first outlet of the electronic proportional three-way valve to an appropriate amount, while controlling the second outlet of the electronic proportional three-way valve to be closed to an appropriate amount, thereby connecting the condensing heat recovery section coil 191 to the high-temperature and high-pressure gaseous refrigerant. The central controller controls the coolant circulation pump to gradually increase the speed, thereby causing the coolant in the heat pipe circulation recovery front section coil 121 and the heat pipe circulation recovery rear section coil 161 to enter a circulating flow state.

[0050] At this time, the outdoor fresh air is filtered by the primary filter of the fresh air primary filter section 11 and then enters the heat pipe circulation recovery front section 12 for the first pre-cooling and cooling, with a cooling range of about 6-9°C.

[0051] The cooled fresh air enters the primary return air section, where it mixes with the indoor primary return air. The resulting mixed fresh air, at a medium temperature and high humidity, enters the surface cooling section 14 for pre-cooling before entering the evaporator section 15. By adjusting the primary return air ratio control valve 131 to increase the primary return air volume, the primary return air volume can reach 80% of the total return air volume. This provides sufficient air volume to remove the cooling capacity of the surface cooling section and the evaporator, ensuring that the evaporator's maximum cooling capacity during deep dehumidification does not freeze, achieving rapid cooling of the mixed fresh air. The evaporator section 15 connects to the refrigerant intermediate-pressure section 34 and the condensation heat recovery section 19. The intermediate-pressure vapor refrigerant in the intermediate-pressure section 34 and the condensation heat recovery section 19 passes through a two-way one-way valve, a filter drier 151, and an electronic pressure reducing valve 152 before entering the evaporator coil 153 to absorb heat, cooling and dehumidifying the primary mixed fresh air passing through the evaporator section 15. The fresh air temperature after dehumidification in the evaporator section 15 drops to 8-13°C.

[0052] After dehumidification, the primary mixed fresh air enters the heat pipe recycling section 16 for cold recovery. The temperature of this primary mixed fresh air is raised to approximately 13-18°C. The primary mixed fresh air is then remixed with the indoor secondary return air in the secondary return air section, reaching a temperature of approximately 17-21°C. The secondary mixed fresh air is then fed by the supply fan 171 into the medium-efficiency filtration section 18. After being filtered by the medium-efficiency filter 181, it enters the condensation heat recovery section 19 to recover the condensation heat from the condensation heat recovery coil 191. After being treated in the condensation heat recovery section 19, the secondary mixed fresh air is fed to the reheat coil section 20, gradually bringing the mixed fresh air temperature to a preset range. At this point, the humidification section 21 is deactivated. When the mixed fresh air reaches the preset temperature and humidity range, it is fed through the air duct into the high-efficiency filtration section for filtration. Finally, the mixed fresh air is delivered to the indoor room at a temperature that meets various requirements, such as temperature, humidity, dust particle count, and pressure differential. The fresh air system achieves energy savings of up to 70%.

[0053] In summary, the present application introduces indoor return air and outdoor fresh air for mixing by placing the primary return air system and the secondary return air system before and after the evaporation section and the surface cooling section, respectively, making full use of the processing advantages of each section, so that the coordination between the return air system and the functional sections of the air intake unit is more reasonable; in addition, the return air ratio of the primary return air and the secondary return air is dynamically adjusted by the automatic control system, so that the reheat of the entire fresh air device is reduced to a minimum, and the energy consumption is reduced exponentially during the entire processing process, while extending the service life of the equipment. Since the temperature and humidity of outdoor fresh air vary greatly in different regions and seasons, by presetting the required indoor temperature and humidity range, the central controller automatically adjusts the working status of each section and the outdoor unit according to the outdoor fresh air and indoor temperature and humidity values ​​monitored by the temperature sensor and the preset values, and adjusts the fresh air temperature and humidity quickly and stably on the basis of saving energy.

[0054] The above description is merely an embodiment of the present application, which is only used to help understand the present application and is not intended to limit the scope of protection of the present application. It should be noted that for those skilled in the art, several improvements made without departing from the principles of the present application should also be considered as the scope of protection of the present application.

Claims

1. A fresh air device, characterized in that: It includes the air intake unit and the outdoor unit, including: The air intake unit includes, from the fresh air inlet end to the fresh air outlet end, a fresh air primary filter section, a heat pipe circulation recovery front section, a primary return air system, a surface cooling section, an evaporation section, a heat pipe circulation recovery rear section, a secondary return air system, a condensation heat recovery section, and a reheat coil section, wherein: The heat pipe circulation recovery front section and the heat pipe circulation recovery rear section form a closed loop to recycle and utilize the sensible heat of the fresh air; The primary return air system includes a primary return air section and a primary return air duct connected to the primary return air section to introduce indoor return air and outdoor fresh air for primary mixing; The secondary return air system includes a secondary return air section and a secondary return air duct connected to the secondary return air section to introduce indoor return air and outdoor fresh air for secondary mixing, wherein the secondary return air section is provided with an air supply fan; The external unit includes a compressor, a condenser, a low-pressure refrigerant section, a medium-pressure refrigerant section, and a high-pressure refrigerant section connected to the compressor. An electronic regulating three-way valve is provided in the external unit. The inlet end of the electronic regulating three-way valve is connected to the compressor to receive the high-pressure refrigerant compressed by the compressor. The first outlet end of the electronic regulating three-way valve is connected to the inlet end of the condensation heat recovery section via the high-pressure refrigerant section, and the second outlet end of the electronic regulating three-way valve is connected to the medium-pressure refrigerant section via the condenser. The inlet end of the evaporation section is provided with a decompression device and is communicated with the outlet end of the condensation heat recovery section and the refrigerant medium-pressure section, and the outlet end of the evaporation section is communicated with the refrigerant low-pressure section.

2. The fresh air device according to claim 1, characterized in that: A medium-efficiency filter is also provided in the secondary return air section.

3. The fresh air device according to claim 1, characterized in that: The evaporation section includes an evaporation coil, and a drying filter is further provided at the inlet end of the evaporation coil.

4. The fresh air device according to claim 1, characterized in that: The air intake unit further includes a medium-efficiency filtering section arranged after the secondary return air section and before the condensation heat recovery section.

5. The fresh air device according to claim 1, characterized in that: The fresh air device also includes an automatic control system, which includes a central controller and a compressor frequency controller, a temperature and humidity preset module, a temperature and humidity sensor arranged at the fresh air inlet, temperature and humidity sensors installed at the primary return air inlet and the secondary return air inlet, and a switch controller arranged at each section. The central controller is used to compare the temperature and humidity range preset by the temperature and humidity preset module with the temperature and humidity values ​​read by the temperature and humidity sensor at the fresh air inlet and the temperature and humidity sensors at the primary return air inlet and the secondary return air inlet, and automatically adjust the return air ratio of the primary return air and the secondary return air and the working status of each other section.

6. The fresh air device according to claim 5, characterized in that: The switch controller provided in each section further includes a primary return air proportional regulating valve provided in the primary return air duct and a secondary return air proportional regulating valve provided in the secondary return air duct, a proportional electric valve provided on the surface cooling section, and a control switch provided on the reheat coil section.

7. The fresh air device according to claim 6, characterized in that: The air intake unit further includes a humidifying section arranged after the reheat coil section, and the switch controller arranged on each section further includes a control switch connected to the central controller and arranged on the humidifying section.

8. The fresh air device according to claim 1, characterized in that: The air intake unit also includes a high-efficiency filtering section arranged at the fresh air outlet end.

9. The fresh air device according to any one of claims 5 to 7, characterized in that: The preset temperature range is 19-24℃, and the humidity range is 40%-65%.

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