CN115789904A - Intelligent air volume control system and control method for inhibiting new coronary pneumonia propagation risk - Google Patents

Intelligent air volume control system and control method for inhibiting new coronary pneumonia propagation risk Download PDF

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CN115789904A
CN115789904A CN202310063761.0A CN202310063761A CN115789904A CN 115789904 A CN115789904 A CN 115789904A CN 202310063761 A CN202310063761 A CN 202310063761A CN 115789904 A CN115789904 A CN 115789904A
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indoor
air
fresh air
air valve
room
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CN115789904B (en
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崔璨
薛璟
苏明伟
黎明
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Ocean University of China
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Abstract

The invention relates to the technical field of ventilation control, and provides an intelligent air volume control system and method for inhibiting the propagation risk of new coronary pneumonia. Determining the metabolic intensity coefficient and the respiratory rate of the human body of the indoor personnel according to the total number of the indoor personnel and the proportion of the personnel wearing the mask; according to the number of indoor infected people, the initial virus generation amount and the virus attenuation rate; calculating the infection probability; and calculating the indoor minimum required fresh air volume according to the infection probability. And the air valve controller adjusts the opening of the air valve according to the minimum required fresh air volume. The method provided by the invention can obtain the minimum fresh air quantity value which is more real and reliable and can control the infection risk below the safety threshold, and the opening of the air valve of the system arranged in the indoor tail end device is adjusted to send the required fresh air quantity into the room, thereby reducing the virus diffusion risk.

Description

Intelligent air volume control system and control method for inhibiting new coronary pneumonia propagation risk
Technical Field
The invention relates to the technical field of ventilation system control, in particular to an intelligent air volume control system and method for inhibiting the spreading risk of new crown pneumonia.
Background
The new coronary pneumonia (COVID-19) is an infectious respiratory disease caused by a novel SARS-CoV-2 virus, has strong transmission, and the sharp increase of cases brings great pressure to the health department and the society, so that the establishment of an effective epidemic prevention control strategy to prevent the virus transmission and reduce the infection risk is very important. Most COVID-19 infections occur in indoor environments, and the main transmission route is air transmission. Ventilation is important to limit the propagation of COVID-19 in the indoor air, and aerosol particles with infectious viruses in the indoor air can be diluted and replaced by artificially introducing fresh outdoor air to reduce the infection and propagation risk of the viruses.
During the virus outbreak period, the ratio is 30m 3 The ventilation standard per hour/person is far from sufficient to prevent and control viral transmission, and in order to minimize the risk of infection, the optimal fresh air requirement of most indoor environments is close to or slightly lower than 60m after the comprehensive effect of various relieving measures is considered 3 Per hour, the maximum ventilation measure is adopted, and great energy waste is inevitably caused. In 2022, the virus stable epidemic period with only a few people infected is entered, and the continuous implementation of the high-intensity intervention measures same as the outbreak period causes great resource waste. The survey found that the energy consumption of the Chinese ventilation system increased by 128% during the virus pandemic. Blindly reducing the amount of fresh air in the room also increases the risk of virus transmission in the room. Therefore, the ventilation of the indoor environment needs to be dynamically adjusted and controlled, and the building energy conservation is realized on the basis of ensuring the safety and health of indoor personnel.
In controlling the risk of COVID-19 propagation in an indoor environment, ventilation requirements are mainly measured by the amount of viral quantum emissions, and the required outdoor fresh air volume is calculated by the quantum emission rate and the probability of infection based on the Wells-Riley model. The model provides a quantitative relationship between infection risk and fresh air volume without changing the virus production rate. However, the Wells-Riley model and most models based thereon have several limitations. Most models are built on assumptions that in many cases tend to be unrealistic. This causes inaccuracies in estimating the risk of infection, which in turn causes a large deviation of the calculated fresh air volume from the actual demand.
The Wells-Riley model implicitly assumes that quantum accumulation is a time-independent process, with a fixed probability (63.2%) of infection per quantum. I.e. the probability of infection is only related to the total amount of inhaled pathogens, and is not related to the length of contact time; while pathogens that accumulate over time are more likely to overwhelm the immune system than if exposed to low levels for extended periods of time, this time-independent assumption is not always true, particularly when the exposure period is relatively long, which can lead to errors. Furthermore, the Wells-Riley model assumes that the human breathing rate is stable. However, in different indoor environments, the behaviors and environmental characteristics of people are greatly different, physical activities (such as movement, standing and sitting) performed indoors influence the metabolism rate of a human body, and the metabolism intensity inevitably influences the virus inhalation and exhalation efficiency of infected persons and susceptible persons, so that the estimation of infection risks is influenced. Moreover, the Wells-Riley model does not consider the influence of physical epidemic prevention measures such as wearing a mask and the like on the inhalation efficiency of the virus quantum. In the current epidemic prevention measures, although in the indoor, most people are required to wear the mask when entering public areas such as shopping malls and offices to reduce the risk of virus infection, and the literature proves that the wearing of the filtering mask can effectively reduce the risk of infection.
Disclosure of Invention
The invention aims to improve a virus infection risk assessment model aiming at the defects of a virus assessment model in the prior art, is applied to an indoor environment provided with a ventilation system, and solves the problem of indoor fresh air regulation and control in a virus propagation environment so as to reduce the risk of indoor virus propagation.
In order to achieve the above object, the present invention adopts the following technical solutions.
An intelligent air volume control system for inhibiting the propagation risk of new coronary pneumonia comprises a fresh air system, a face detection system and a control system;
the new trend system includes: the system comprises a fresh air machine, an indoor fresh air pipeline and an indoor exhaust pipeline; the outdoor fresh air pipeline is connected with the indoor fresh air pipeline through the fresh air fan, and the indoor exhaust pipeline is connected with the outdoor exhaust pipeline through the fresh air fan; indoor fresh air pipeline includes indoor air outlet, indoor air outlet department is provided with: the air valve, the air valve controller and the air quantity measuring device are arranged on the air valve; the air valve controller receives a control system command to control the opening of the air valve;
the face detection system comprises an image acquisition device, a control system and a face recognition device, wherein the image acquisition device is arranged at an indoor door, is communicated with the control system and is used for detecting the number of indoor personnel and whether the personnel wear masks or not;
the control system is used for counting the occupation ratio of the indoor personnel with the masks based on the images acquired by the face detection system; the control system further calculates minimum required fresh air volume which corresponds to indoor design air supply volume, and the air valve controller controls the opening of an air valve based on the minimum required fresh air volume;
the controller is configured to calculate a minimum required fresh air volume as follows:
Figure SMS_1
；
wherein:
Figure SMS_3
the number of infected people in the room is,
Figure SMS_6
representing the initial quantum generation rate at which symptoms occur,
Figure SMS_8
is the metabolic intensity coefficient of the indoor environment,
Figure SMS_4
is the lung breathing rate (m) of the person indoors 3 /s)，
Figure SMS_5
The number of people with the mask is more than that of people in the room,
Figure SMS_9
the efficiency of the filtration of the mask is improved,
Figure SMS_11
total exposure time to the viral environment for an indoor susceptible;
Figure SMS_2
time since symptoms occurred for the infected;γrepresenting the decay rate of pathogens accumulated in the respiratory tract of a susceptible individual;
Figure SMS_7
is the lung breathing rate of the person in the room,
Figure SMS_10
indicating the total number of people in the room.
Calculating indoor minimum required fresh air volume
Figure SMS_12
Is calculated by
Figure SMS_13
>When 0 is satisfied, therefore, the ventilation amount is further designed as follows:
if it is
Figure SMS_14
>0, according to the infection probability and the basic virus propagation number
Figure SMS_15
The minimum required fresh air volume in the room is calculated by controlling the limit condition within 1
Figure SMS_16
：
Figure SMS_17
；
Figure SMS_18
；
If it is
Figure SMS_19
Less than or equal to 0, and the total number of people in the room is 0,the number of infected persons is also 0, and ventilation is carried out according to the minimum fresh air design standard in the normal period;
if it is
Figure SMS_20
Is less than or equal to 0, and
Figure SMS_21
or is or
Figure SMS_22
According to 60m 3 The/h/person standard gives ventilation or maximum ventilation measures.
In some embodiments of the present invention, an air volume measuring device is further disposed at the indoor air outlet, and is configured to detect an actual air volume at the outlet of the air valve; and the control system further adjusts the opening degree of the air valve based on the difference value between the indoor actual air supply value measured at the air outlet of the air valve and the indoor designed air supply corresponding to the fresh air volume.
In some embodiments of the present invention, the face detection system further includes a temperature sensing device for detecting the body temperature of the person entering the room.
Some embodiments of the present invention further provide an intelligent air volume control method for suppressing a risk of COVID-19 propagation, including the following steps:
s1: counting the total number of indoor personnel
Figure SMS_23
And proportion of person wearing the mask
Figure SMS_24
Determining the metabolic intensity coefficient of human body of indoor personnel
Figure SMS_25
And respiration rate
Figure SMS_26
；
S2: determining the number of infected persons in a room
Figure SMS_27
Initial viral quantum production rate at onset of symptoms
Figure SMS_28
Attenuation rate of pathogens accumulated in respiratory tract of susceptible personγ(ii) a Calculating the probability of infection
Figure SMS_29
；
Figure SMS_30
；
Wherein:
Figure SMS_32
the number of the indoor susceptible people is as follows,
Figure SMS_34
the number of cases of infection due to exposure to airborne virus particles in the room,
Figure SMS_36
is the metabolic intensity coefficient of the indoor environment,
Figure SMS_33
total exposure time to the viral environment for an infected person indoors;
Figure SMS_35
time since onset of symptoms for infected persons;
Figure SMS_37
the number of people with the mask is more than that of people in the room,
Figure SMS_38
in order to improve the filtering efficiency of the mask,γ(ii) indicates the decay rate of pathogens accumulated in the respiratory tract of a susceptible individual;
Figure SMS_31
is the pulmonary respiration rate of the indoor person;
Figure SMS_39
for true inhalation by susceptible personsPathogen quantum number:
Figure SMS_40
；
Figure SMS_41
indicating the number of pathogens in the host over a period of time;
s3: calculating indoor ventilation volume;
if it is
Figure SMS_42
>0, according to the infection probability and the basic virus propagation number
Figure SMS_43
The minimum required fresh air volume in the room is calculated by controlling the limit condition within 1
Figure SMS_44
：
Figure SMS_45
；
Figure SMS_46
；
If it is
Figure SMS_47
The total indoor number is less than or equal to 0, the number of infected persons is 0, and ventilation is performed according to the minimum fresh air design standard in the normal period;
if it is
Figure SMS_48
Is less than or equal to 0, and
Figure SMS_49
or is or
Figure SMS_50
According to 60m 3 Ventilation or maximum ventilation measures are taken according to the per/person standard;
s4: confirm indoor design air supply volume based on minimum demand fresh air volume
Figure SMS_51
According to the indoor design air supply amount
Figure SMS_52
And adjusting the opening of the air valve.
In some embodiments of the present invention, the method further comprises the steps of:
measuring actual air supply quantity at outlet of air valve
Figure SMS_53
；
Calculating the actual air supply quantity at the outlet of the air valve
Figure SMS_54
Indoor design air supply amount
Figure SMS_55
Adjusting the air valve opening degree:
Figure SMS_56
；
wherein:
Figure SMS_57
the opening degree of the air valve is adjusted,
Figure SMS_58
is at present
Figure SMS_59
The corresponding opening degree of the air valve is set,
Figure SMS_60
is a proportional control coefficient which is a function of,
Figure SMS_61
is an integral control coefficient.
In some embodiments of the invention, if the actual air output of the air valve outlet is
Figure SMS_62
Indoor design air supply amount
Figure SMS_63
And stopping adjusting the opening degree of the air valve when the difference is smaller than the set threshold value.
In some embodiments of the present invention, in step S3, the ratio between the total number of people indoors and the ratio between the number of people indoors wearing the mask is updated according to the detection result of the face detection system.
In some embodiments of the invention, for a household:
Figure SMS_64
is 1;
for shopping malls, stations, airports:
Figure SMS_65
is 1.5;
for a gymnasium:
Figure SMS_66
is 2.
Compared with the prior art, the invention has the advantages and positive effects that:
1. the original Wells-Riley model is improved, the influence of the attenuation of pathogens exhaled by an infected person along with time, the change of human activity intensity on the change of the lung ventilation rate and the filtering effect of physical measures such as mask wearing and the like on inhaled viruses are comprehensively considered, the obtained improved model is more real and accurate in estimation of the virus infection probability, the limitation that the original Wells-Riley model is partially assumed to be difficult to meet under the actual condition is made up, the required fresh air volume obtained through calculation is more reliable and is closer to the actual requirement, and the reduction of ventilation energy consumption can be realized while the indoor infection risk is controlled within the safety threshold.
2. The face detection system is configured and used for monitoring personnel flow and connecting the personnel flow with the full ventilation system to realize information interaction, so that the ventilation system can obtain the dynamic change condition of the fresh air volume in time, and the opening degree of an air valve at the tail end of the fresh air volume in the indoor environment can be adjusted in time to meet the fresh air requirement.
3. According to the invention, the virus infection risk in the indoor environment is used as an index of the ventilation requirement, so that the virus infection risk of indoor susceptible persons is controlled within a safety threshold value as a ventilation target, and the ventilation requirement is calculated and obtained and a fresh air system is driven to control. By taking the air pollution as an index, the air pollution and virus propagation in public buildings can be efficiently controlled, so that the ventilation effect on indoor personnel is more effective.
Drawings
FIG. 1 is a schematic view of an indoor ventilation system;
FIG. 2 is a schematic diagram of an indoor ventilation control logic structure;
in the above figures:
1-a fresh air machine;
2-indoor fresh air pipeline, 201-indoor air outlet;
3-indoor exhaust pipeline, 301-indoor exhaust outlet;
4-outdoor inlet pipe;
5-outdoor air exhaust pipelines;
6-an image acquisition device;
7-monitoring screen.
Detailed Description
The invention is described in detail below by way of exemplary embodiments. It should be understood, however, that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
The invention provides an intelligent air volume control system and a control method for inhibiting the spreading risk of new crown pneumonia.
The first embodiment of the invention firstly provides an intelligent air volume control system for inhibiting the spreading risk of new coronary pneumonia (COVID-19), which comprises a fresh air system, a face detection system and a control system.
Referring to fig. 1, a fresh air system is provided in a room, including: the system comprises a fresh air fan 1, an indoor fresh air pipeline 2 and an indoor exhaust pipeline 3; the outdoor inlet pipeline 4 is connected with the indoor fresh air pipeline 2 through a fresh air fan, and the indoor exhaust pipeline 3 is connected with the outdoor exhaust pipeline 5 through the fresh air fan. The indoor fresh air pipeline 2 and the indoor exhaust pipeline 3 are arranged on the top of a room and can be installed on the ceiling.
Indoor fresh air pipeline 2 is last to be provided with indoor air outlet 201, and indoor air outlet 201 department is provided with: the air valve, the air valve controller and the air quantity measuring device are arranged on the air valve; and the air valve controller receives a control system command to control the opening degree of the air valve. The control of indoor air inlet quantity can be adjusted by changing the opening of the air valve.
An indoor air outlet 301 for discharging indoor air is provided on the indoor air discharge duct 3. The fresh air system adopts the traditional form of upward feeding and upward returning of mixed ventilation, and the indoor air outlet 201 and the indoor air outlet 301 are respectively arranged at two corresponding sides in a room, so that the indoor air can be fully diluted and mixed conveniently.
Face detection system includes image acquisition device 6, sets up and is being gone into indoor door department, and with control system communication, when personnel pass through the room entrance door, carry out image acquisition to whether wear the gauze mask according to image analysis person of entering the room.
The control system counts the number of the masks in the indoor personnel based on the images collected by the face detection system; the control system further calculates the minimum required fresh air volume which corresponds to the indoor design air supply volume, and the air valve controller controls the opening of the air valve based on the minimum required fresh air volume;
the controller is configured to calculate a minimum required fresh air volume as follows:
Figure SMS_67
；
wherein:
Figure SMS_68
the number of infected people in the room is,
Figure SMS_71
representing the initial rate of viral quantum production at the onset of symptoms,
Figure SMS_74
is the metabolic intensity coefficient of the indoor environment,
Figure SMS_69
is a chamberPulmonary respiration rate (m) of the inner person 3 /s)，
Figure SMS_72
The number of people with the mask is more than that of people in the room,
Figure SMS_75
the mask filtration efficiency;
Figure SMS_77
total exposure time to an indoor viral environment for an indoor susceptible person;
Figure SMS_70
time since symptoms occurred for infected individuals indoors;
Figure SMS_73
representing the decay rate of pathogens accumulated in the respiratory tract of a susceptible individual;
Figure SMS_76
indicating the total number of people in the room.
Above formula when
Figure SMS_78
>When 0, the formula is established, and the minimum threshold value of the indoor design fresh air volume is obtained;
when in use
Figure SMS_79
When the ventilation quantity is less than or equal to 0, the method for acquiring the ventilation quantity is detailed later.
In some embodiments of the present invention, an air volume measuring device is further disposed at the indoor air outlet, and is configured to detect an actual air volume at the outlet of the air valve; and the control system further adjusts the opening degree of the air valve based on the difference value between the indoor actual air supply value measured at the air outlet of the air valve and the indoor designed air supply corresponding to the fresh air volume.
In some embodiments of the present invention, the face detection system further comprises a temperature sensing device for detecting the body temperature of the person entering the room. Whether the body temperature of the personnel is abnormal or not is monitored in real time, so that early warning is facilitated and virus propagation is controlled.
In some embodiments of the invention, a monitoring display screen 7 is arranged indoors and used for recording the real-time in-and-out conditions of indoor personnel based on a face detection system, and recording and uploading the real-time temperature of a human body based on a body temperature monitoring system.
The second embodiment of the present invention further provides an intelligent air volume control method for suppressing the risk of spreading new coronary pneumonia (COVID-19), which improves the original Wells-Riley model and re-evaluates the level of infection risk indoors.
Before describing the method of the present invention, first the model improvement and the calculation of the air volume based on the improved model will be described.
For the original Wells-Riley model, quanta were defined as the number of infectious airborne particles required to infect a person. It may consist of one or more airborne virus-carrying particles that are assumed to be randomly distributed in the air of the enclosed space. According to the model, the probability of infection of an airborne pathogen of an infectious respiratory disease is defined as:
Figure SMS_80
this formula is the most primitive model of Wells-Riley and is currently the steady-state epidemic of the virus, which inevitably occurs when infected and uninfected individuals are co-located in one room. Wherein the content of the first and second substances,
Figure SMS_82
is the probability of viral infection of a susceptible person in the room,
Figure SMS_85
the number of the indoor susceptible people is as follows,
Figure SMS_87
the number of cases of secondary infection due to exposure to airborne virus particles in a room is usually unknown.
Figure SMS_81
Is the number of initial infectious persons in the room, i.e. the generationPathogen personnel (the body temperature detection system is used for capturing the abnormal body temperature to achieve the purpose of controlling risks in advance, or a data platform or nucleic acid detection is used for proving whether the person entering a room is an infected person or not);
Figure SMS_84
is the pulmonary respiration rate (m) of the person in the room 3 /s) (the value has a correlation with the following parameters,
Figure SMS_88
(60/h) average level corresponding to resting/passive activity: (
Figure SMS_90
=0.5 m 3 /h））；
Figure SMS_83
Is the rate of viral quantum production (m) of the infected person 3 /s) (the parameter can be obtained by calculation);
Figure SMS_86
the fresh air volume (m) introduced into the room 3 S) (the control system controls the fresh air volume by adjusting and controlling the fresh air fan and the air valve);
Figure SMS_89
is the total exposure time(s) of an uninfected person to the viral environment (viral environment refers to the indoor environment after the virus is exhaled by an infected person when present indoors).
Assuming that the air in the indoor space is in a stable state and is completely mixed with the introduced fresh air volume, the method comprises the following steps according to a dose reaction model:
Figure SMS_91
Figure SMS_92
wherein the content of the first and second substances,γshows the attenuation rate of pathogens accumulated in the respiratory tract of susceptible persons (conservative estimate of 0.1/h, forShould the longest viral half-life of the survey data be available),
Figure SMS_93
indicating the number of pathogens in the host over a certain time (this parameter belongs to an intermediate variable),
Figure SMS_94
represents the initial number of pathogens that accumulate in the respiratory tract of the host.
The virus amount on the pharyngeal swab of COVID-19 infected persons was found to decrease gradually after symptoms appeared. Therefore, the quantum yield, which is considered to be proportional to the viral load
Figure SMS_95
And also decreases over time. According to the time law of the virus shedding curve described in the previous research, the mathematical fitting expression of the time-varying quantum generation rate of the COVID-19 infected person can be obtained as follows:
Figure SMS_96
wherein the content of the first and second substances,
Figure SMS_97
representing the initial rate of viral quantum production at the onset of symptoms (based on previous findings,
Figure SMS_98
may be determined to be substantially 60/h),
Figure SMS_99
is the time since the onset of symptoms in infected individuals indoors.
The intensity of the human activity in the room affects the metabolism of the body, and the intensity of metabolism determines the inhalation and exhalation rates. Thus, if the pulmonary ventilation rate is high, the rate of viral quantum production will be higher in infected individuals. The metabolic intensity coefficients of different indoor environments were recorded as
Figure SMS_100
Multiples of lung breathing rate and resting state). The parameters are set as follows: at home, the user can use the device to set the position,
Figure SMS_101
is 1; in the places such as classrooms, offices, subways, restaurants and the like,
Figure SMS_102
is 1.25; in the places such as movie theaters, shopping malls, railway stations, airports and the like,
Figure SMS_103
is 1.5; in a gymnasium or the like,
Figure SMS_104
is 2. The value of the indoor environment metabolic intensity coefficient is comprehensively selected according to indexes such as indoor personnel density, indoor environment air fluidity and the like.
Thus, quantum yield of infected persons
Figure SMS_105
And pulmonary ventilation rate in room susceptible
Figure SMS_106
The change in (b) will have a multiplicative effect on the risk of infection. The total viral quantum yield of the infected was:
Figure SMS_107
wherein, the first and the second end of the pipe are connected with each other,
Figure SMS_108
to the total quantum yield since the onset of symptoms,
Figure SMS_109
is the total exposure time of a susceptible person to the viral environment.
According to the number of people entering the room and the number of people wearing the mask, which are obtained by counting by the detection device, the indoor mask wearing number ratio is calculated
Figure SMS_110
(%), the filtration efficiency of the mask was set to
Figure SMS_111
(%). The susceptible really inhales the quantum quantity of the pathogen
Figure SMS_112
Comprises the following steps:
Figure SMS_113
thus, improved probability of infection is obtained after a combination of pathogen attenuation, lung ventilation rate variation and mask filtration under the Wells-Riley model
Figure SMS_114
The (updated model) can be expressed as:
Figure SMS_115
based on the updated model, the minimum required air supply may be calculated.
Basic number of reproduction
Figure SMS_116
Refers to the number of secondary infections that result when a single infectious case is introduced into a population where others are all susceptible. Generally, the larger the value, the more likely the infection will rapidly reproduce in the form of an epidemic. If, however, there is a
Figure SMS_117
Less than 1, the epidemic will eventually disappear, and therefore a control measure capable of reducing the number of breeding to less than 1 is considered to be effective.
According to the number of initial infected persons in the room
Figure SMS_118
And detecting the total number of indoor people
Figure SMS_119
And the calculated improved probability of infection
Figure SMS_120
The basic reproduction number can be calculated
Figure SMS_121
Comprises the following steps:
Figure SMS_122
considering the need to control the basic number of reproduction to below 1, there are:
Figure SMS_123
the calculated requirement value of the design requirement fresh air volume is as follows:
Figure SMS_124
therefore, if
Figure SMS_125
>0, the minimum value of the indoor fresh air volume requirement is as follows:
Figure SMS_126
。
and after the minimum design air volume is obtained through calculation, the opening degree of an air valve at the variable air volume tail end of a ventilation system is controlled by relying on a full air system installed indoors, and the required new air volume is sent indoors, so that the propagation risk of the virus is controlled within an acceptable threshold value.
Based on the updated model, the control method provided by the invention comprises the following steps.
S1: counting the total number of indoor people
Figure SMS_129
And proportion of person wearing the mask
Figure SMS_131
Determining the metabolic intensity coefficient of human body of indoor personnel
Figure SMS_135
And respiration rate
Figure SMS_130
(ii) a Wherein the total number of indoor people
Figure SMS_133
Can be obtained by detection and statistics of the face detection device, and accounts for the proportion of people wearing the mask
Figure SMS_137
May be obtained based on the total number of persons and the total number of persons detected by the face detection device. The metabolic intensity coefficients of different indoor environments are
Figure SMS_138
(multiple of lung ventilation rate and resting state), the following were set: at home, the user can use the device to set up the device,
Figure SMS_127
is 1; in classrooms, offices, subways, and restaurants,
Figure SMS_134
is 1.25; in cinemas, malls, train stations/airports and KTV etc.,
Figure SMS_136
is 1.5; in the body-building room, the body-building room is provided with a plurality of air bags,
Figure SMS_139
is 2.
Figure SMS_128
(60/h) average level corresponding to resting/passive activity: (
Figure SMS_132
=0.5 m 3 H), the parameters can be obtained according to the general knowledge documentation in the field.
S2: determining persons infected indoorsNumber of
Figure SMS_140
Initial amount of virus production
Figure SMS_141
And rate of viral attenuationγ(ii) a Calculating the probability of infection
Figure SMS_142
；
Figure SMS_143
。
Wherein:
Figure SMS_144
the number of the indoor susceptible people is as follows,
Figure SMS_148
the number of cases of infection due to exposure to airborne virus particles in the room,
Figure SMS_150
representing the initial quantum generation rate at which symptoms occur,
Figure SMS_146
is the metabolic intensity coefficient of the indoor environment,
Figure SMS_147
total exposure time;
Figure SMS_151
time since symptoms occurred for infected individuals indoors;
Figure SMS_152
the number of people with the mask is more than that of people in the room,
Figure SMS_145
the mask filtration efficiency;γrepresenting the decay rate of pathogens accumulated in the respiratory tract of a susceptible individual;
Figure SMS_149
is the lung breathing rate of the indoor person.
Figure SMS_153
The number of actual inhaled pathogen quanta for a susceptible:
Figure SMS_154
；
Figure SMS_155
indicating the number of pathogens in the host over a period of time.
S3: calculating indoor required fresh air volume;
the calculation of the fresh air volume is classified into the following cases according to the relationship between the total number of indoor people and the number of indoor infected people.
If it is
Figure SMS_156
>0, according to the infection probability and the basic virus propagation number
Figure SMS_157
The limit condition of controlling within 1 is required to calculate the indoor minimum required fresh air volume
Figure SMS_158
：
Figure SMS_159
。
Wherein:
Figure SMS_160
indicating the total number of people in the room.
When the temperature is higher than the set temperature
Figure SMS_161
When the content is less than or equal to 0, the following cases are roughly classified:
1. the total number of the infected people is 0, namely the infected people are transferred to the indoor without infected people, the ventilation aims at removing residual viruses in indoor air, and ventilation can be performed according to the lowest fresh air design standard in the normal period;
2、
Figure SMS_162
that is, all indoor people are infected or the indoor environment is a special area such as a ward, the purpose of ventilation is to ventilate and dilute virus generated by infected people, and provide fresh air for indoor people according to 60m 3 Ventilation or maximum ventilation measures are taken per hour per person, and necessary virus killing measures are taken to avoid virus diffusion;
3、
Figure SMS_163
and is
Figure SMS_164
When the number of infected people is more than that of susceptible people, the infected people are easy to be infected, and the uninfected people in the room are transferred preferentially at the moment, and the distance is 60m 3 The ventilation is carried out by the standard of/h/person or the maximum design fresh air volume of a fresh air system; (the maximum design value is related to the selection of the fresh air system and the model of the fresh air fan).
S4: fresh air quantity confirmation indoor design air quantity confirmed based on the situation
Figure SMS_165
According to the indoor design air supply amount
Figure SMS_166
And adjusting the opening of the air valve.
In some embodiments of the present invention, the method further comprises the steps of:
measuring the actual air supply quantity of the outlet of the air valve at each moment
Figure SMS_167
(ii) a Calculating the actual air supply quantity at the outlet of the air valve
Figure SMS_168
Indoor design air supply amount
Figure SMS_169
Adjusting the air valve opening degree:
Figure SMS_170
；
wherein:
Figure SMS_171
the opening degree of the air valve is adjusted,
Figure SMS_172
is at present
Figure SMS_173
The corresponding opening degree of the air valve is set,
Figure SMS_174
is a proportional control coefficient which is a function of,
Figure SMS_175
is an integral control coefficient.
In the unsteady state, the actual air blowing amount at each time of the outlet of the damper
Figure SMS_176
Is a time-varying value, and the indoor air supply amount is designed at each moment
Figure SMS_177
May vary with the parameters, for example: the total number of people in the room varies, the number of infected people varies, etc. Thus, regulation is a dynamic process.
In some embodiments of the invention, if the actual air output of the air valve outlet is
Figure SMS_178
Indoor design air supply amount
Figure SMS_179
And stopping adjusting the opening degree of the air valve when the difference is smaller than the set threshold value. Generally, if it reaches
Figure SMS_180
And
Figure SMS_181
the difference between the two meets the control requirement, and the control target can be regarded as being achieved within 10% generally, namely, the ventilation requirement is met. Obtaining the target air valve opening degree which enables the indoor actual air supply quantity to meet the required air supply quantity
Figure SMS_182
。
It should be noted that close contact with the infected person was found to result in a higher risk of contacting the COVID-19 virus by short-range droplet transmission. This spray propagation can be overcome by maintaining a sufficient physical distance. When kept at a distance of more than 1.5 meters from the infected person, the virus concentration will drop to a constant level. Since the present invention does not take into account short-range droplet propagation of viruses, in practical applications, the above proposed ventilation control strategy should be applied together with epidemic prevention measures such as maintaining physical distance.
The method provided by the invention can obtain the minimum fresh air value which is more real and reliable and can control the infection risk below the safety threshold, and transmits the calculated value to the fresh air system, and adjusts the opening degree of a middle air valve of a terminal device of the system installed in the indoor environment, so that the required fresh air quantity is sent into the room, and the virus diffusion risk is reduced.
The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention in other forms, and any person skilled in the art may apply the above modifications or changes to the equivalent embodiments with equivalent changes, without departing from the technical spirit of the present invention, and any simple modification, equivalent change and change made to the above embodiments according to the technical spirit of the present invention still belong to the protection scope of the technical spirit of the present invention.

Claims (8)

1. An intelligent air volume control system for inhibiting the spreading risk of new coronary pneumonia is characterized by comprising a new air system, a face detection system and a control system;
the new trend system includes: the system comprises a fresh air fan, an indoor fresh air pipeline and an indoor exhaust pipeline; the outdoor fresh air pipeline is connected with the indoor fresh air pipeline through a fresh air fan, and the indoor exhaust pipeline is connected with the outdoor exhaust pipeline through the fresh air fan; indoor fresh air pipeline includes indoor air outlet, indoor air outlet department is provided with: the air valve, the air valve controller and the air quantity measuring device are arranged on the air valve; the air valve controller receives a control system instruction to control the opening degree of the air valve;
the human face detection system comprises an image acquisition device, a control system and a human face detection module, wherein the image acquisition device is arranged at an indoor door, is communicated with the control system and is used for detecting the number of indoor personnel and whether the indoor personnel wear the mask or not;
the control system counts the number of the masks in the indoor personnel based on the images collected by the face detection system; the control system further calculates minimum required fresh air volume which corresponds to indoor design air supply volume, and the air valve controller controls the opening of an air valve based on the minimum required fresh air volume;
the controller is configured to calculate a minimum required fresh air volume as follows:
Figure QLYQS_1
；
wherein:
Figure QLYQS_4
the number of infected people in the room is,
Figure QLYQS_5
representing the initial rate of viral quantum production at the onset of symptoms,
Figure QLYQS_9
is a metabolic intensity coefficient of an indoor environment,
Figure QLYQS_3
is the lung breathing rate of the person in the room,
Figure QLYQS_7
the number of people with the mask is more than that of people in the room,
Figure QLYQS_8
in order to improve the filtering efficiency of the mask,
Figure QLYQS_10
total exposure time to the viral environment for a susceptible;
Figure QLYQS_2
time since onset of symptoms for infected persons;γrepresenting the decay rate of pathogens accumulated in the respiratory tract of a susceptible individual;
Figure QLYQS_6
indicating the total number of people in the room.
2. The intelligent air volume control system for inhibiting the propagation risk of the new crown pneumonia according to claim 1, wherein an air volume measuring device is further arranged at the indoor air outlet and used for detecting the actual air volume at the air outlet of the air valve; the control system further adjusts the opening degree of the air valve based on the difference value between the indoor actual air supply quantity value measured at the air outlet of the air valve and the corresponding indoor design fresh air supply quantity.
3. The intelligent airflow control system for inhibiting the risk of transmission of new crown pneumonia according to claim 1 wherein said face detection system further comprises a temperature sensing device for detecting the body temperature of the person entering the room.
4. An intelligent air volume control method for inhibiting the risk of spreading new coronary pneumonia is characterized by comprising the following steps:
s1: counting the total number of indoor personnel
Figure QLYQS_11
And proportion of person wearing the mask
Figure QLYQS_12
Determining the metabolic intensity coefficient of the human body of the indoor person
Figure QLYQS_13
And respiration rate
Figure QLYQS_14
；
S2: determining the number of infected persons in a room
Figure QLYQS_15
Initial viral quantum production rate at onset of symptoms
Figure QLYQS_16
Attenuation rate of pathogens accumulated in respiratory tract of susceptible personγ(ii) a Calculating the probability of infection
Figure QLYQS_17
；
Figure QLYQS_18
；
Wherein:
Figure QLYQS_21
the number of the indoor susceptible people is as follows,
Figure QLYQS_22
the number of cases of infection due to exposure to airborne virus particles in the room,
Figure QLYQS_25
is the metabolic intensity coefficient of the indoor environment,
Figure QLYQS_19
total exposure time to the viral environment for an indoor susceptible;
Figure QLYQS_23
is the time since onset of symptoms in the initial infected person;
Figure QLYQS_24
the number of people with the mask is more than that of people in the room,
Figure QLYQS_26
in order to improve the filtering efficiency of the mask,γ(ii) indicates the decay rate of pathogens accumulated in the respiratory tract of a susceptible individual;
Figure QLYQS_20
is the lung breathing rate of the person indoors;
Figure QLYQS_27
the number of quanta of pathogen actually inhaled by a susceptible:
Figure QLYQS_28
；
Figure QLYQS_29
indicating the number of pathogens in the host over a period of time;
s3: calculating indoor ventilation volume;
if it is
Figure QLYQS_30
>0, according to the infection probability and the basic virus propagation number
Figure QLYQS_31
The minimum required fresh air volume in the room is calculated by controlling the limit condition within 1
Figure QLYQS_32
：
Figure QLYQS_33
；
Figure QLYQS_34
；
If it is
Figure QLYQS_35
The total indoor number is less than or equal to 0, the number of infected persons is 0, and ventilation is performed according to the minimum fresh air design standard in the normal period;
if it is
Figure QLYQS_36
Is less than or equal to 0, and
Figure QLYQS_37
or is or
Figure QLYQS_38
According to 60m 3 Ventilation or maximum ventilation measures are taken according to the/h/person standard;
s4: indoor design air supply volume is confirmed based on new air volume
Figure QLYQS_39
According to the indoor design air supply volume
Figure QLYQS_40
And adjusting the opening of the air valve.
5. The intelligent air volume control method for inhibiting the risk of spreading new crown pneumonia according to claim 4, characterized by further comprising the steps of:
measuring actual air supply quantity at outlet of air valve
Figure QLYQS_41
；
Calculating the actual air supply quantity at the outlet of the air valve
Figure QLYQS_42
Indoor design air supply amount
Figure QLYQS_43
Adjusting the air valve opening degree:
Figure QLYQS_44
；
wherein:
Figure QLYQS_45
the opening degree of the air valve is adjusted,
Figure QLYQS_46
is at present
Figure QLYQS_47
The corresponding opening degree of the air valve is set,
Figure QLYQS_48
is a proportional control coefficient that is a function of,
Figure QLYQS_49
is an integral control coefficient.
6. The intelligent air volume control method for inhibiting the risk of the spread of new coronary pneumonia according to claim 5, characterized in that: if the actual air supply quantity of the outlet of the air valve
Figure QLYQS_50
Indoor design air supply amount
Figure QLYQS_51
And stopping adjusting the opening degree of the air valve when the difference is smaller than the set threshold value.
7. The intelligent air volume control method for inhibiting the risk of the spread of new coronary pneumonia according to claim 4, characterized by comprising: and in the step S3, updating the total number of people in the room according to the detection result of the face detection system.
8. The intelligent air volume control method for inhibiting the risk of the spread of new coronary pneumonia according to claim 4, characterized by comprising:
for the family: metabolic intensity coefficient of indoor environment
Figure QLYQS_52
Is 1;
for shopping malls, stations, airports: metabolic intensity coefficient of indoor environment
Figure QLYQS_53
Is 1.5;
for a gymnasium: metabolic intensity coefficient of indoor environment
Figure QLYQS_54
Is 2.
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