Exhaust purification indirect evaporative cooling heat recovery fresh air handling unit and operation method thereof

Abstract

According to the exhaust purification indirect evaporative cooling heat recovery fresh air handling unit and the operation method thereof, a photocatalytic reactor is applied to the exhaust heat recovery fresh air handling unit, exhaust purification and exhaust heat recovery can be achieved at the same time, and the exhaust purification indirect evaporative cooling heat recovery fresh air handling unit is applied to an air conditioning system of a high-density crowd building. The problem of exhaust pollution is solved, public health and safety are guaranteed, meanwhile, the evaporative cooling heat recovery technology is combined with a heat pump heat recovery system, exhaust energy is recovered to the maximum extent, the exhaust heat recovery rate is increased, and energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The present invention relates to the field of fresh air system devices and fresh air system control technology, and in particular to an exhaust air purification indirect evaporative cooling heat recovery fresh air unit and an operation method thereof. Background Art

[0002] Under normal conditions, in order to ensure indoor comfort and health needs, in high-density crowd buildings such as office buildings, shopping malls, classrooms and auditoriums, the demand for fresh air is higher than that of other buildings. Therefore, the fresh air load required for heating and cooling fresh air during the operation of the air-conditioning system is relatively high. In the face of public health problems such as the high incidence of respiratory infectious diseases, in order to block the spread of aerosols formed by viruses, one is to open windows for natural ventilation and dilution, but many existing buildings do not have the conditions for opening windows for ventilation; the second is to increase the fresh air supply volume of the air-conditioning system, but most of the existing fresh air systems do not consider the operating conditions of the whole fresh air. On the other hand, increasing the fresh air volume will cause a sharp increase in fresh air energy consumption. At the same time, in order to ensure the indoor pressure balance, it is necessary to directly discharge the contaminated air that may carry the virus to the outdoors. Therefore, the present invention proposes an exhaust purification indirect evaporative cooling heat recovery fresh air unit to solve the technical problem that the fresh air load of high-density crowd buildings facing emergencies increases sharply, and a large amount of direct exhaust wind has potential risks and causes huge energy losses. Summary of the invention

[0003] In view of this, the object of the present invention is to propose an exhaust air purification indirect evaporative cooling heat recovery fresh air unit and an operating method thereof which are reliable in implementation, flexible in application and have good use effect.

[0004] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0005] An exhaust purification indirect evaporative cooling heat recovery fresh air unit, comprising:

[0006] The housing has an installation cavity formed therein, and the installation cavity has two air flow channels separated by a partition;

[0007] The heat exchange core is a cross-counterflow plate heat exchanger, which is installed between the two air flow channels and divides them into a first channel, a second channel, a third channel and a fourth channel. The heat exchange core has two groups of heat exchange channels that cross each other but are not interconnected, wherein the two ends of one group of heat exchange channels are respectively connected to the first channel and the third channel, and the two ends of the other group of heat exchange channels are respectively connected to the second channel and the fourth channel;

[0008] A photocatalytic reactor is disposed in the first channel and is used to purify the air input into the first channel. The housing is provided with an exhaust inlet corresponding to the first channel.

[0009] A first heat exchanger is disposed in the second channel;

[0010] a second heat exchanger, disposed in the fourth channel and connected to the first heat exchanger via a pipeline;

[0011] The compressor is connected to the first heat exchanger and the second heat exchanger respectively through a four-way valve, and the first heat exchanger is used as a condenser and the second heat exchanger is used as an evaporator or the second heat exchanger is used as a condenser and the first heat exchanger is used as an evaporator by switching the four-way valve.

[0012] A first spray assembly is disposed in the housing, with a spray end thereof extending to the first channel, and is used for spraying a heat exchange pipe of the heat exchange core connected to the first channel;

[0013] A second spray assembly is disposed in the housing, a spray end of which extends to the fourth channel and is used for spraying the second heat exchanger;

[0014] Among them, the first spray assembly and the second spray assembly are both connected to an external water supply pipeline, the casing is provided with a fresh air inlet corresponding to the third channel; the casing is provided with a fresh air outlet corresponding to the second channel, and the casing is provided with an exhaust outlet corresponding to the fourth channel, and the fresh air outlet and the exhaust outlet are both provided with fans for assisting in conveying airflow.

[0015] As a possible implementation method, further, the solution also includes:

[0016] The water pump is arranged on the main pipe connecting the first spray assembly and the second spray assembly to the external water supply pipe, and the main pipe is provided with one-to-one corresponding water pipe branches corresponding to the first spray assembly and the second spray assembly.

[0017] As a preferred embodiment, preferably, the first spray assembly in this solution includes:

[0018] A first valve is arranged on a branch of a water pipe corresponding to the first spray assembly of the main pipe;

[0019] The first spray head is set as the spray end of the first spray assembly, which is arranged in the first channel and is used to spray the heat exchange pipe connecting the heat exchange core to the first channel. The first spray head is connected to the main pipe corresponding to the water pipe branch of the first spray assembly.

[0020] As a preferred embodiment, preferably, the second spray assembly in this solution includes:

[0021] A second valve is arranged on a branch of a water pipe corresponding to the second spray assembly of the main pipe;

[0022] The second spray head is set as the spray end of the second spray assembly, which is arranged in the fourth channel and used for spraying the second heat exchanger. The second spray head is connected to the main line corresponding to the water pipe branch of the second spray assembly.

[0023] Based on the above, this solution also proposes an operation method of an exhaust purification indirect evaporative cooling heat recovery fresh air unit, which is applied with the exhaust purification indirect evaporative cooling heat recovery fresh air unit described above; the operation method includes:

[0024] Execute one of the following operation modes according to the preset conditions:

[0025] (1) Summer operation mode;

[0026] (2) Winter operation mode;

[0027] (3) Transition season operation mode.

[0028] As a preferred implementation mode, preferably, the summer operation mode described in this solution includes the following:

[0029] The first spray assembly is turned on to spray water, so that the heat exchange core acts as a plate heat recovery heat exchanger. In the heat pump system composed of the first heat exchanger, the second heat exchanger and the compressor, the first heat exchanger acts as an evaporator and the second heat exchanger acts as a condenser. At the same time, the second spray assembly is also turned on to spray water;

[0030] Outdoor fresh air enters the third channel from the fresh air inlet, and then passes through the dry channel of the heat exchange core. At the same time, indoor exhaust air enters the first channel from the exhaust air inlet, removes viruses and other pollutants through the photocatalytic reactor, and then enters the wet channel of the heat exchange core. The fresh air input into the third channel is cooled and dehumidified by the exhaust air through the heat exchange core, and then enters the second channel, and then is further cooled and dehumidified by the first heat exchanger serving as an evaporator, and then is sent to the air-conditioned room through the fresh air outlet; the indoor exhaust air is cooled and humidified through the wet channel of the heat exchange core, and then enters the fourth channel, and then flows through the second heat exchanger serving as a condenser, so that it takes away the heat of the condenser, and then is discharged to the outdoors through the exhaust outlet.

[0031] As a preferred implementation mode, preferably, the winter operation mode described in this solution includes the following:

[0032] The first spray assembly stops working, and the heat exchange core of the plate heat recovery heat exchanger is converted into a sensible heat exchanger. The refrigerant circulation of the heat pump system composed of the first heat exchanger, the second heat exchanger and the compressor is switched through the four-way reversing valve, so that the first heat exchanger is used as a condenser and the second heat exchanger is used as an evaporator. At the same time, the second spray assembly also stops working;

[0033] Fresh air and indoor exhaust air enter the third channel and the first channel of the fresh air unit through the fresh air inlet and the exhaust air inlet respectively; the exhaust air passes through the photocatalytic reactor to remove harmful substances such as viruses, and then enters the heat exchange core to exchange sensible heat with the fresh air in another heat exchange channel in the heat exchange core. The exhaust air temperature rises, and then enters the evaporator of the heat pump system to exchange heat with the evaporator to provide heat for the heat pump system, and then is discharged to the outside through the exhaust outlet of the fourth channel;

[0034] The fresh air is preheated by the exhaust air through the heat exchange core, and then further heated by the condenser of the heat pump system, and then delivered into the room through the fresh air outlet of the second channel.

[0035] As a preferred implementation method, preferably, the transition season operation mode described in this solution includes the following:

[0036] The compressor of the heat pump system of the fresh air unit does not start; the fresh air enters the room through the bypass duct of the fresh air unit shell;

[0037] The exhaust air enters the first channel through the exhaust inlet, and then the virus and other harmful substances are removed by the photocatalytic reactor, and then it passes through the heat exchange core, the fourth channel and the exhaust outlet in sequence and is discharged to the outside.

[0038] By adopting the above-mentioned technical scheme, the present invention has the following beneficial effects compared with the prior art: this scheme applies the photocatalytic reactor to the exhaust heat recovery fresh air unit, which can simultaneously realize exhaust purification and exhaust heat recovery, and is applied to the air-conditioning system of high-density crowd buildings. It solves the exhaust pollution problem for public health events and ensures public health safety. At the same time, it combines the evaporative cooling heat recovery technology with the heat pump heat recovery system to maximize the recovery of exhaust energy, improve the exhaust heat recovery rate, and achieve energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 This is a brief implementation diagram of the fresh air unit in this scheme in the summer operation mode;

[0041] Figure 2 This is a brief implementation diagram of the fresh air unit in this scheme in winter operation mode. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Similarly, the following examples are only partial embodiments of the present invention rather than all embodiments, and all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0043] Combination Figure 1 or Figure 2 As shown, this embodiment provides an exhaust purification indirect evaporative cooling heat recovery fresh air unit, which includes:

[0044] The housing 100 has an installation cavity formed therein, and the installation cavity has two air flow channels separated by a partition 101;

[0045] The heat exchange core 11 is a cross-counterflow plate heat exchanger, which is installed between the two air flow channels and divides them into a first channel 102, a second channel 103, a third channel 104 and a fourth channel 105. The heat exchange core 11 has two groups of heat exchange channels that cross each other but are not interconnected, wherein the two ends of one group of heat exchange channels are respectively connected to the first channel 102 and the third channel 104, and the two ends of the other group of heat exchange channels are respectively connected to the second channel 103 and the fourth channel 105;

[0046] The photocatalytic reactor 10 is disposed in the first channel 102 and is used to purify the air input into the first channel 102. The housing 100 is provided with an exhaust inlet 1 corresponding to the first channel 102;

[0047] A first heat exchanger 5 is disposed in the second channel 103;

[0048] The second heat exchanger 6 is disposed in the fourth channel 105 and connected to the first heat exchanger 5 through a pipeline;

[0049] The compressor 8 is connected to the first heat exchanger 5 and the second heat exchanger 6 respectively through the four-way valve 9, and the first heat exchanger 5 is used as a condenser and the second heat exchanger 6 is used as an evaporator or the second heat exchanger 6 is used as a condenser and the first heat exchanger 5 is used as an evaporator by switching the four-way valve 9;

[0050] The first spray assembly 13 is disposed in the housing 100, and its spray end extends to the first channel 102, and is used to spray the heat exchange pipe of the heat exchange core 11 connected to the first channel 102;

[0051] The second spray assembly 14 is disposed in the housing 100, with a spray end thereof extending to the fourth channel 105, and is used for spraying the second heat exchanger 6;

[0052] The first spray assembly 13 (or indirect evaporative cooling spray water device) and the second spray assembly 14 (or evaporative condenser spray water device) are both connected to an external water supply pipeline, and the housing 100 is provided with a fresh air inlet 2 corresponding to the third channel 104; the housing 100 is provided with a fresh air outlet 3 corresponding to the second channel 103, and the housing 100 is provided with an exhaust air outlet 4 corresponding to the fourth channel 105, and the fresh air outlet 3 and the exhaust air outlet 4 are both provided with fans 31 and 41 for assisting in conveying airflow;

[0053] The water pump 12 is arranged on a main pipe 121 connecting the first spray assembly 13 and the second spray assembly 14 to an external water supply pipe. The main pipe 121 is provided with one-to-one corresponding water pipe branches corresponding to the first spray assembly 13 and the second spray assembly 14 .

[0054] Among them, as a preferred embodiment, preferably, the first spray assembly 13 of this solution includes:

[0055] A first valve 131 is disposed on a branch of the water pipe corresponding to the first spray assembly 13 of the main pipe;

[0056] The first spray head 132 is set as the spray end of the first spray component 13. It is arranged in the first channel 102 and is used to spray the heat exchange pipe connecting the heat exchange core 11 to the first channel 102. The first spray head 132 is connected to the main line 121 corresponding to the water pipe branch of the first spray component 13.

[0057] As a preferred embodiment, preferably, the second spray assembly 14 of this solution includes:

[0058] A second valve 141 is disposed on a branch of the main pipe 121 corresponding to the second spray assembly 14;

[0059] The second spray head 142 is set as the spray end of the second spray assembly 14, which is arranged in the fourth channel 104 and is used to spray the second heat exchanger 6. The second spray head 142 is connected to the main line 121 corresponding to the water pipe branch of the second spray assembly 14.

[0060] The working principle of the exhaust air purification indirect evaporative cooling heat recovery fresh air unit proposed in this embodiment is as follows: Figure 1 or Figure 2As shown, the equipment is mainly composed of a photocatalytic reactor, an indirect evaporative cooling heat recovery heat exchanger (a first spray component 13), a heat pump system (composed of a first heat exchanger 5, a second heat exchanger 6 and a compressor 8), an evaporative condenser water spray device (a second spray component 14), fans 31, 41 and a casing 100, etc. The indirect evaporative cooling heat recovery heat exchanger may include a plate-type heat recovery heat exchange core 11 and an indirect evaporative cooling water spray device 13.

[0061] For the convenience of control, the present solution can also be connected to the first spray assembly 13 (or indirect evaporative cooling spray water device), the second spray assembly 14 (or evaporative condenser spray water device), fans 31, 41, compressor 8, four-way reversing valve 9, water pump 12 and other components through a controller, and control their operation on and off.

[0062] Based on the above, this solution also proposes an operation method of an exhaust purification indirect evaporative cooling heat recovery fresh air unit, which is applied with the exhaust purification indirect evaporative cooling heat recovery fresh air unit described above; the operation method includes: executing one of the following operation modes according to preset conditions:

[0063] (1) Summer operation mode;

[0064] (2) Winter operation mode;

[0065] (3) Transition season operation mode.

[0066] Focus on combination Figure 1 As shown, as a preferred implementation mode, preferably, the summer operation mode described in this solution includes the following:

[0067] The first spray assembly 13 (or indirect evaporative cooling spray water device) is turned on to spray water, so that the heat exchange core 11 (or plate heat recovery heat exchange core) acts as a plate heat recovery heat exchanger. In the heat pump system composed of the first heat exchanger 5, the second heat exchanger 6 and the compressor 8, the first heat exchanger 5 acts as an evaporator and the second heat exchanger 6 acts as a condenser. At the same time, the second spray assembly 14 (or evaporative condenser spray water device) is also turned on to spray water;

[0068] Outdoor fresh air enters the third channel 104 from the fresh air inlet 2, and then passes through the dry channel of the heat exchange core 11. At the same time, indoor exhaust air enters the first channel 102 from the exhaust air inlet 1, removes pollutants such as viruses through the photocatalytic reactor 10, and then enters the wet channel of the heat exchange core 11. The fresh air input into the third channel 104 is cooled and dehumidified by the exhaust air of the heat exchange core 11, and then enters the second channel 103, and then is further cooled and dehumidified by the first heat exchanger 5 serving as an evaporator, and then is sent to the air-conditioned room through the fresh air outlet 3; the indoor exhaust air is cooled and humidified through the wet channel of the heat exchange core 11, and then enters the fourth channel 105, and then flows through the second heat exchanger 6 serving as a condenser to take away the heat of the condenser, and then is discharged to the outdoors through the exhaust outlet 4.

[0069] Combination Figure 2 As shown, as a preferred implementation mode, preferably, the winter operation mode described in this solution includes the following:

[0070] The first spray assembly 13 (or indirect evaporative cooling spray water device) stops working, so that the heat exchange core 11 as a plate heat recovery heat exchanger is converted into a sensible heat exchanger. The refrigerant circulation of the heat pump system composed of the first heat exchanger 5, the second heat exchanger 6 and the compressor 8 is switched through the four-way reversing valve 9, so that the first heat exchanger 5 is used as a condenser and the second heat exchanger 6 is used as an evaporator. At the same time, the second spray assembly 14 (or evaporative condenser spray water device) also stops working;

[0071] Fresh air and indoor exhaust air enter the third channel 104 and the first channel 102 of the fresh air unit through the fresh air inlet 2 and the exhaust air inlet 1 respectively; the exhaust air passes through the photocatalytic reactor 10 to remove harmful substances such as viruses, and then enters the heat exchange core 11 to exchange sensible heat with the fresh air in another heat exchange channel in the heat exchange core 11, and the exhaust air temperature rises, and then enters the evaporator (second heat exchanger 6) of the heat pump system, exchanges heat with the evaporator (second heat exchanger 6), provides heat for the heat pump system, and then is discharged to the outside through the exhaust outlet of the fourth channel 105;

[0072] The fresh air is preheated by the exhaust air through the heat exchange core 11 , and then further heated by the condenser (the first heat exchanger 5 ) of the heat pump system, and then delivered into the room through the fresh air outlet 3 of the second channel 103 .

[0073] In addition to the above, as a preferred implementation mode, preferably, the transition season operation mode described in this solution includes the following:

[0074] The compressor of the heat pump system of the fresh air unit does not start; the fresh air enters the room through the bypass duct of the fresh air unit shell;

[0075] The exhaust air enters the first channel through the exhaust inlet, and then the virus and other harmful substances are removed by the photocatalytic reactor, and then it passes through the heat exchange core, the fourth channel and the exhaust outlet in sequence and is discharged to the outside.

[0076] The above descriptions are only some embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An exhaust purification indirect evaporative cooling heat recovery fresh air unit, characterized in that: It includes: The housing has an installation cavity formed therein, and the installation cavity has two air flow channels separated by a partition; The heat exchange core is a cross-counterflow plate heat exchanger, which is installed between the two air flow channels and divides them into a first channel, a second channel, a third channel and a fourth channel. The heat exchange core has two groups of heat exchange channels that cross each other but are not interconnected, wherein the two ends of one group of heat exchange channels are respectively connected to the first channel and the third channel, and the two ends of the other group of heat exchange channels are respectively connected to the second channel and the fourth channel; A photocatalytic reactor is disposed in the first channel and is used to purify the air input into the first channel. The housing is provided with an exhaust inlet corresponding to the first channel. A first heat exchanger is disposed in the second channel; a second heat exchanger, disposed in the fourth channel and connected to the first heat exchanger via a pipeline; The compressor is connected to the first heat exchanger and the second heat exchanger respectively through a four-way valve, and the first heat exchanger is used as a condenser and the second heat exchanger is used as an evaporator or the second heat exchanger is used as a condenser and the first heat exchanger is used as an evaporator by switching the four-way valve. A first spray assembly is disposed in the housing, with a spray end thereof extending to the first channel, and is used for spraying a heat exchange pipe of the heat exchange core connected to the first channel; A second spray assembly is disposed in the housing, a spray end of which extends to the fourth channel and is used for spraying the second heat exchanger; Among them, the first spray assembly and the second spray assembly are both connected to an external water supply pipeline, the casing is provided with a fresh air inlet corresponding to the third channel; the casing is provided with a fresh air outlet corresponding to the second channel, and the casing is provided with an exhaust outlet corresponding to the fourth channel, and the fresh air outlet and the exhaust outlet are both provided with fans for assisting in conveying airflow.

2. The exhaust purification indirect evaporative cooling heat recovery fresh air unit according to claim 1, characterized in that: Also includes: The water pump is arranged on the main pipe connecting the first spray assembly and the second spray assembly to the external water supply pipe, and the main pipe is provided with one-to-one corresponding water pipe branches corresponding to the first spray assembly and the second spray assembly.

3. The exhaust air purification indirect evaporative cooling heat recovery fresh air unit according to claim 2, characterized in that: The first spray assembly comprises: A first valve is arranged on a branch of a water pipe corresponding to the first spray assembly of the main pipe; The first spray head is set as the spray end of the first spray assembly, which is arranged in the first channel and is used to spray the heat exchange pipe connecting the heat exchange core to the first channel. The first spray head is connected to the main pipe corresponding to the water pipe branch of the first spray assembly.

4. The exhaust purification indirect evaporative cooling heat recovery fresh air unit according to claim 2, characterized in that: The second spray assembly comprises: A second valve is arranged on a branch of a water pipe corresponding to the second spray assembly of the main pipe; The second spray head is set as the spray end of the second spray assembly, which is arranged in the fourth channel and used for spraying the second heat exchanger. The second spray head is connected to the main line corresponding to the water pipe branch of the second spray assembly.

5. An operating method of an exhaust purification indirect evaporative cooling heat recovery fresh air unit, characterized in that: The invention uses the exhaust purification indirect evaporative cooling heat recovery fresh air unit according to any one of claims 1 to 4; the operation method comprises: Execute one of the following operation modes according to the preset conditions: (1) Summer operation mode; (2) Winter operation mode; (3) Transition season operation mode.

6. The method for operating an exhaust purification indirect evaporative cooling heat recovery fresh air unit according to claim 5, characterized in that: The summer operation mode includes the following: The first spray assembly is turned on to spray water, so that the heat exchange core acts as a plate heat recovery heat exchanger. In the heat pump system composed of the first heat exchanger, the second heat exchanger and the compressor, the first heat exchanger acts as an evaporator and the second heat exchanger acts as a condenser. At the same time, the second spray assembly is also turned on to spray water; Outdoor fresh air enters the third channel from the fresh air inlet, and then passes through the dry channel of the heat exchange core. At the same time, indoor exhaust air enters the first channel from the exhaust air inlet, removes viruses and other pollutants through the photocatalytic reactor, and then enters the wet channel of the heat exchange core. The fresh air input into the third channel is cooled and dehumidified by the exhaust air through the heat exchange core, and then enters the second channel, and then is further cooled and dehumidified by the first heat exchanger serving as an evaporator, and then is sent to the air-conditioned room through the fresh air outlet; the indoor exhaust air is cooled and humidified through the wet channel of the heat exchange core, and then enters the fourth channel, and then flows through the second heat exchanger serving as a condenser, so that it takes away the heat of the condenser, and then is discharged to the outdoors through the exhaust outlet.

7. The method for operating an exhaust purification indirect evaporative cooling heat recovery fresh air unit according to claim 5, characterized in that: The winter operation mode includes the following: The first spray assembly stops working, and the heat exchange core of the plate heat recovery heat exchanger is converted into a sensible heat exchanger. The refrigerant circulation of the heat pump system composed of the first heat exchanger, the second heat exchanger and the compressor is switched through the four-way reversing valve, so that the first heat exchanger is used as a condenser and the second heat exchanger is used as an evaporator. At the same time, the second spray assembly also stops working; Fresh air and indoor exhaust air enter the third channel and the first channel of the fresh air unit through the fresh air inlet and the exhaust air inlet respectively; the exhaust air passes through the photocatalytic reactor to remove harmful substances such as viruses, and then enters the heat exchange core to exchange sensible heat with the fresh air in another heat exchange channel in the heat exchange core. The exhaust air temperature rises, and then enters the evaporator of the heat pump system to exchange heat with the evaporator to provide heat for the heat pump system, and then is discharged to the outside through the exhaust outlet of the fourth channel; The fresh air is preheated by the exhaust air through the heat exchange core, and then further heated by the condenser of the heat pump system, and then delivered into the room through the fresh air outlet of the second channel.

8. The method for operating an exhaust purification indirect evaporative cooling heat recovery fresh air unit according to claim 5, characterized in that: The transition season operation mode includes the following: The compressor of the heat pump system of the fresh air unit does not start; the fresh air enters the room through the bypass duct of the fresh air unit shell; The exhaust air enters the first channel through the exhaust inlet, and then the virus and other harmful substances are removed by the photocatalytic reactor, and then it passes through the heat exchange core, the fourth channel and the exhaust outlet in sequence and is discharged to the outside.

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