CN115789904B - Intelligent air volume control system and control method for inhibiting new crown pneumonia propagation risk - Google Patents
Intelligent air volume control system and control method for inhibiting new crown pneumonia propagation risk Download PDFInfo
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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 propagation risk of new coronaries pneumonia. Determining the metabolic intensity coefficient and the respiration rate of the human body of the indoor personnel according to the total number of the indoor personnel and the occupancy rate of the personnel wearing the mask; according to the number of indoor infectious people, the initial virus generation amount and the virus attenuation rate; calculating the infection probability; and calculating indoor minimum required fresh air quantity according to the infection probability. And the air valve controller adjusts the opening of the air valve according to the minimum required fresh air quantity. The method provided by the invention can obtain a more real and reliable minimum fresh air quantity value capable of controlling the infection risk below the safety threshold, adjusts the opening of the air valve of the system arranged in the indoor terminal device, sends the required fresh air quantity into the indoor, and can reduce the virus diffusion risk.
Description
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
New coronapneumonia (COVID-19) is an infectious respiratory disease caused by a novel SARS-CoV-2 virus, has strong transmissibility, and causes great pressure on health departments and society due to the rapid increase of cases, so that it is important to develop an effective epidemic prevention control strategy to prevent the transmission of the virus and reduce the infection risk. Most of the infection with covd-19 occurs in indoor environments, the main transmission route being airborne. Ventilation is important to limit spread of covd-19 in indoor air by artificially introducing fresh air outside the room to dilute and replace aerosol particles with infectious virus inside the room to reduce the risk of infection and spread of the virus.
During viral outbreak, according to 30m 3 The ventilation criteria/h/person are far from adequate for preventing and controlling viral transmission, and in order to minimize the risk of infection, the optimal fresh air requirement for most indoor environments is near or slightly below 60m after considering the combined effects of various mitigation measures 3 Per h/person, taking maximum limitA measure of ventilation inevitably results in a great waste of energy. However, 2022 has entered a period of stable virus flow with only a few people infected, and continuing to perform the same high-intensity intervention as the outbreak period causes great resource waste. And blindly reducing the indoor fresh air volume can also increase the risk of virus propagation in the room. Therefore, the ventilation of the indoor environment needs to be dynamically adjusted and controlled, and the energy saving of the building is realized on the basis of ensuring the safety and the health of indoor personnel.
In controlling the risk of spread of the covd-19 in indoor environments, ventilation requirements are measured primarily by viral quantum emissions, and the required outdoor fresh air volume is calculated by quantum emissivity and infection probability based on the Wells-Riley model. The model provides a quantitative relationship between infection risk and fresh air volume with the virus production rate unchanged. However, the Wells-Riley model and the majority of models based thereon have several limitations. Most models are built on assumptions which in many cases tend to be unrealistic. Therefore, the estimated infection risk is inaccurate, and the calculated fresh air quantity is greatly deviated 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 each quantum carrying out an infection. I.e. the probability of infection is only related to the total amount of inhaled pathogen, not to the length of contact time; and pathogens that accumulate over time are more likely to overwhelm the immune system than if they were exposed to low levels of pathogens over a long period of time, such time-independent assumptions are not always practical, and may lead to errors, particularly when the exposure period is relatively long. Furthermore, the Wells-Riley model assumes that the respiration rate of the human body is stable. However, in different indoor environments, the behaviors and environmental characteristics of the personnel are very different, and the physical activities (such as exercise, standing and sitting) performed indoors affect the metabolism rate of the human body, and the metabolism intensity inevitably affects the inhalation and exhalation efficiency of the infected person and the infected person on viruses, so as to affect the estimation of the infection risk. Moreover, the Wells-Riley model does not consider the influence of physical epidemic prevention measures such as mask wearing on the inhalation efficiency of virus quanta. Meanwhile, the literature proves that the infection risk can be effectively reduced by wearing the filtering mask.
Disclosure of Invention
The invention aims to solve the problem of indoor fresh air regulation control in a virus transmission environment so as to reduce the risk of indoor virus transmission.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows.
An intelligent air volume control system for inhibiting the spreading risk of new crown pneumonia comprises a fresh air system, a face detection system and a control system;
the fresh air system comprises: 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 a fresh air fan, and the indoor exhaust pipeline is connected with the outdoor exhaust pipeline through a fresh air fan; the indoor fresh air pipeline comprises an indoor air outlet, and the indoor air outlet is provided with: an air valve, an air valve controller and an air flow measuring device; the air valve controller receives a control system instruction to control the opening degree of the air valve;
the face detection system comprises an image acquisition device, a control system and a face detection system, wherein the image acquisition device is arranged at an indoor door and is communicated with the control system and used for detecting the number of people entering the room and whether the people wear a mask or not;
the control system counts the proportion of the mask in the indoor personnel based on the image acquired by the face detection system; the control system further calculates the minimum required fresh air quantity, the fresh air quantity corresponds to the indoor design air supply quantity, and the air valve controller controls the opening of the air valve based on the minimum required fresh air quantity;
the controller is configured to calculate a minimum required fresh air volume as follows:
wherein:
is the number of people infected indoors and is->
Representing the initial rate of quantum generation at the onset of symptoms, < >>
Is the metabolic intensity coefficient of the indoor environment, +.>
Is the lung respiration rate (m) of the indoor person 3 /s)，/>
The number of people with masks in the room is equal to the ratio +.>
Is the filtering efficiency of the mask, and is->
Total exposure time in the viral environment for indoor susceptible persons; />
Is the time since the occurrence of symptoms for the infected person;γa decay rate indicative of a pathogen accumulated in the respiratory tract of the susceptible individual; />
Is the lung respiration rate of indoor personnel, +.>
Indicating the total number of people in the room.
Calculating indoor minimum required fresh air quantity
The formula of (2) is>
>0, the ventilation is further designed as follows:
if it is
>0, according to infection probability and basic reproduction number of virus +.>
Limiting conditions which need to be controlled within 1, and calculating indoor minimum required fresh air quantity +.>
：
If it is
The total indoor number is 0, the number of infected persons is 0, and ventilation is carried out according to the lowest fresh air design standard in the normal period;
if it is
Less than or equal to 0 and%>
Or->
According to 60m 3 The ventilation is carried out or maximum ventilation measures are taken according to the/h/person standard.
In some embodiments of the present invention, an air volume measuring device is further disposed at the indoor air outlet, and is used for detecting the actual air volume of the air valve outlet; the control system further adjusts the opening 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 design air supply quantity corresponding to the fresh air quantity.
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 inhibiting spread risk of a covd-19, including the following steps:
s1: counting total number of indoor personnel
And the proportion of the wearer who wears the mask>
Determining the metabolic intensity coefficient of the human body of the indoor personnel>
Respiratory rate->
；
S2: determining the number of people who are infected indoors
Initial viral Quantum Generation Rate at symptomatic onset +.>
Attenuation rate of pathogens accumulated in respiratory tract of person susceptible to infectionγThe method comprises the steps of carrying out a first treatment on the surface of the Calculating infection probability->
；
Wherein:
is the number of people easy to be infected in the room, +.>
For the number of cases infected by exposure to virus particles in the room, the air-exposed virus particles are exposed to the air>
Is the metabolic intensity coefficient of the indoor environment, +.>
Total exposure time to viral environment for the indoor infected person; />
Is the time since the occurrence of symptoms for the infected person; />
The number of people with masks in the room is equal to the ratio +.>
The filtering efficiency of the mask is achieved,γa decay rate indicative of a pathogen accumulated in the respiratory tract of the susceptible individual; />
Is the lung respiration rate of indoor personnel;
s3: calculating indoor ventilation quantity;
if it is
>0, according to infection probability and basic reproduction number of virus +.>
Limiting conditions which need to be controlled within 1, and calculating indoor minimum required fresh air quantity +.>
：
If it is
The total indoor number is 0, the number of infected persons is 0, and ventilation is carried out according to the lowest fresh air design standard in the normal period;
if it is
Less than or equal to 0 and%>
Or->
According to 60m 3 Ventilation is carried out or maximum ventilation measures are taken according to the/h/person standard;
s4: indoor design air supply quantity is confirmed based on minimum required fresh air quantity
According to indoor design air supply quantity ∈>
And adjusting the opening degree of the air valve.
In some embodiments of the invention, the method further comprises the steps of:
measuring the actual air supply quantity of the outlet of the air valve
；
Calculating the actual air supply quantity of the outlet of the air valve
And the indoor design air supply quantity +>
And (3) adjusting the opening degree of the air valve:
wherein:
is to adjust the opening of the rear air valve>
Is at present +.>
Corresponding air valve opening degree, < >>
Is a proportion control coefficient, and the control coefficient is a proportion control coefficient,
is an integral control coefficient.
In some embodiments of the invention, if the air valve outlet is actually supplying air
And the indoor design air supply quantity +>
And stopping adjusting the opening 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 of the total indoor population to the mask worn by the indoor population is updated according to the detection result of the face detection system.
In some embodiments of the invention, for a household:
1 is shown in the specification;
for malls, stations, airports:
1.5;
for gymnasium：
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 the activity intensity of a human body on the change of the pulmonary ventilation rate and the filtering effect of physical measures like wearing masks on inhaled viruses are comprehensively considered, the evaluation of the obtained improved model on the virus infection probability is more real and accurate, the limitation that the part of the assumption of the original Wells-Riley model is difficult to meet in the actual situation is made up, the calculated fresh air quantity of the requirement is more reliable, the requirement is closer to the actual requirement, and the reduction of ventilation energy consumption can be realized while the indoor infection risk is controlled within a safety threshold.
2. The face detection system is configured for monitoring the flow of personnel, and is connected with the full ventilation system to realize information interaction, so that the ventilation system can obtain the dynamic change condition of fresh air quantity in time, and the opening of the air valve at the tail end of variable air quantity in the indoor environment can be adjusted in time to meet the fresh air requirement.
3. The invention takes the virus infection risk in the indoor environment as an index of ventilation requirement to realize that the virus infection risk of the indoor easily infected person is controlled within the safety threshold as a ventilation target, thereby calculating the ventilation requirement and driving the fresh air system to control. The method can realize the efficient control of air pollution and virus transmission in public buildings by taking the method as an index, 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 the indoor ventilation control logic;
in the above figures:
1-a fresh air machine;
2-an indoor fresh air pipeline and 201-an indoor air outlet;
3-an indoor exhaust pipeline and 301-an indoor exhaust port;
4-outdoor inlet pipeline;
5-an outdoor exhaust pipeline;
6-an image acquisition device;
7-monitor screen.
Detailed Description
The present invention will be specifically described below by way of exemplary embodiments. It is to be understood 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 an intelligent air volume control method for inhibiting the spreading risk of new coronaries.
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, comprising: 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 a fresh air fan. The indoor fresh air pipeline 2 and the indoor exhaust pipeline 3 are both arranged to be attached to the top of a room, and can be installed at a ceiling generally.
An indoor air outlet 201 is arranged on the indoor fresh air pipeline 2, and an indoor air outlet 201 is provided with: an air valve, an air valve controller and an air flow measuring device; the air valve controller receives a control system instruction to control the opening degree of the air valve. The control of indoor air inlet quantity can be regulated by changing the opening of the air valve.
An indoor air outlet 301 is provided in the indoor air exhaust duct 3 for exhausting indoor air. The fresh air system adopts a traditional upward-feeding and upward-returning mode 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 indoor air can be diluted and mixed fully.
The face detection system comprises an image acquisition device 6 which is arranged at the indoor door and is communicated with the control system, and when a person passes through the indoor door, the image acquisition is carried out, and whether the person wears a mask or not is analyzed according to the image.
The control system counts the number of masks in indoor personnel based on the images acquired by the face detection system; the control system further calculates the minimum required fresh air quantity, the fresh air quantity corresponds to the indoor design air supply quantity, and the air valve controller controls the opening of the air valve based on the minimum required fresh air quantity;
the controller is configured to calculate a minimum required fresh air volume as follows:
wherein:
is the number of people infected indoors and is->
Representing the initial viral quantum yield at the onset of symptoms, < >>
Is the metabolic intensity coefficient of the indoor environment, +.>
Is the lung respiration rate (m) of the indoor person 3 /s)，/>
The number of people with masks in the room is equal to the ratio +.>
The filtering efficiency of the mask is achieved; />
Total exposure time of the indoor susceptible to the indoor viral environment; />
Time since symptoms occurred for the person who is indoor; />
A decay rate indicative of a pathogen accumulated in the respiratory tract of the susceptible individual; />
Indicating the total number of people in the room.
The above formula is as
>When 0, the formula is established, and a minimum threshold value of the indoor design fresh air quantity is obtained;
when (when)
And less than or equal to 0, the method for obtaining the ventilation is described in detail later.
In some embodiments of the present invention, an air volume measuring device is further disposed at the indoor air outlet, and is used for detecting the actual air volume of the air valve outlet; the control system further adjusts the opening 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 design air supply quantity corresponding to the fresh air quantity.
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 and virus transmission control are facilitated.
In some embodiments of the present invention, a monitor display 7 is disposed indoors, which is used for recording real-time in-out situations of indoor personnel based on the face detection system, and recording and uploading real-time temperature of human body based on the body temperature monitoring system.
The second embodiment of the present invention further provides an intelligent air volume control method for inhibiting the risk of transmission of new coronary pneumonia (covd-19), which improves the original Wells-Riley model and re-evaluates the risk level of infection in the room.
Before describing the method of the present invention, model improvement and calculation of the air volume based on the improved model are described first.
For the original Wells-Riley model, quanta are defined as the number of infectious airborne particles needed to infect a person. It may consist of one or more airborne virus-carrying particles which are assumed to be randomly distributed in the air of the enclosed space. According to the model, the probability of airborne infection of pathogens of infectious respiratory diseases is defined as:
the formula is the most primitive Wells-Riley model, and is currently the steady flow period of the virus, it is inevitable that the infected and uninfected persons are co-located. Wherein, the liquid crystal display device comprises a liquid crystal display device,
is the probability of viral infection for the person in the room susceptible to infection, < >>
Is the number of people easy to be infected in the room, +.>
The number of cases of secondary infection due to exposure to virus particles in the room to air is usually unknown. />
The method is that the initial infection number in the room, namely the personnel generating pathogens (the abnormal body temperature number is captured by a body temperature detection system to achieve the aim of controlling risks in advance, or whether the personnel entering the room are the infection persons is known by a data platform or a nucleic acid detection proof and the like); />
Is the lung respiration rate (m) of the indoor person 3 S) (this value has a correlation with the following parameters,/-)>
(60/h) corresponds to the average level of resting/passive activity (+)>
=0.5 m 3 /h））；/>
The rate of viral quantum production (m) 3 S) (the parameter can be obtained by calculation); />
Is the fresh air quantity (m) 3 S) (the control system controls the fresh air quantity through the adjustment control of the fresh air fan and the air valve); />
Is the total exposure time(s) of the uninfected person to the viral environment (viral environment refers to the indoor environment after the infectious person exhales the virus when present indoors).
Assuming that the air in the indoor space is in a stable state and is completely mixed with the fresh air quantity introduced, the method comprises the following steps of:
wherein, the liquid crystal display device comprises a liquid crystal display device,γrepresents the attenuation rate of pathogens accumulated in the respiratory tract of the susceptible person (conservatively estimated to be 0.1/h, corresponding to the longest viral half-life in the existing investigation data),
represents the number of pathogens (this parameter belongs to an intermediate variable) in the host over a period of time,/i>
Representing the initial number of pathogens accumulated in the respiratory tract in the host.
It was found that the viral load on throat swabs of covd-19 infected individuals gradually decreased after symptoms appeared. Thus, quantum yield believed to be proportional to viral load
And also decreases over time. According to the time law of the virus shedding curve described in the previous study, the mathematical fitting expression of the time-varying quantum generation rate of the infected person of the COVID-19 can be obtained as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
represents the initial viral quantum yield at the time of symptom occurrence (based on the results of previous studies,/i>
Can be determined substantially to be 60/h),>
is the time since symptoms occur for the person who is in the room.
The intensity of the activity of the human body in the room affects the metabolism of the body, and the metabolic intensity determines the inspiration and expiration rates. Thus, if the pulmonary ventilation rate is higher, the viral quantum yield of the infected person will be higher. The metabolic intensity coefficients of different indoor environments are recorded as
Lung respiration rate and resting state). The parameters were set as follows: at home, the person is in the home>
1 is shown in the specification; in classrooms, offices, subways, restaurants, etc.)>
1.25; in movie theatres, shops, train stations, airports etc.)>
1.5; in gymnasiums and the like, the user is in the need of being wore about>
2. The value of the metabolic intensity coefficient of the indoor environment is comprehensively selected according to indexes such as the indoor personnel concentration, the air mobility of the indoor environment and the like.
Thus, the quantum yield of the infected person
And pulmonary ventilation rate of indoor susceptible person +.>
The variation of (c) will have a doubling effect on the risk of infection. The total viral quantum produced by the infected person is:
wherein, the liquid crystal display device comprises a liquid crystal display device,
total quantum yield from symptom occurrence, < +.>
Is the total exposure time of the susceptible to the viral environment.
According to the number of people entering the room and the number of people wearing the mask counted by the detection device, the indoor number of people wearing the mask is calculated to be the ratio
(%) the filtering efficiency of the mask is set as +.>
(%) and the following. The pathogen quantum number truly inhaled by the infected person>
The method comprises the following steps:
therefore, after pathogen attenuation, lung ventilation rate change and filtering effect of the mask are comprehensively considered under a Wells-Riley model, the improved infection probability is obtained
The (updated model) can be expressed as:
based on the updated model, the minimum required air delivery volume can be calculated.
Basic reproduction number
Refers to the number of secondary infections that result when a single infection case is introduced into a population where the other is all susceptible. In general, the greater the value, the more likely an infection will rapidly reproduce in the form of an epidemic. And if->
Below 1, the epidemic will eventually disappear, and thus control measures capable of reducing the number of reproductions to below 1 are considered to be effective.
According to the number of people initially infected indoors
And the total number of detected indoor personnel +.>
And the calculated improved infection probability +.>
Can calculate the basic reproduction number +.>
The method comprises the following steps:
considering that the basic breeding number needs to be controlled below 1, there are:
the calculated demand value of the new air quantity of the design demand is as follows:
thus, if
>0, the minimum value of indoor fresh air volume demand is: />
After the minimum design air quantity is calculated, the opening degree of an air valve at the tail end of variable air quantity of the ventilation system is controlled by means of a full fresh air system installed indoors, and the required fresh air quantity is sent into the indoors, so that the spreading risk of viruses 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 total number of indoor personnel
And the proportion of the wearer who wears the mask>
Determining the metabolic intensity coefficient of the human body of the indoor personnel>
Respiratory rate->
The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the total number of people in the room is->
Can be obtained by detection statistics of a face detection device, and the proportion of the wearer who wears the mask is +.>
Can be obtained based on the total number of people and the total number of people detected by the face detection device. The metabolic intensity coefficient of different indoor environments is +.>
(times of pulmonary ventilation rate and resting state) is set as follows: at home, the person is in the home>
1 is shown in the specification; in classrooms, offices, subways and restaurants, < ->
1.25; in movie theatres, shops, train stations/airports and KTV etc.)>
1.5; in gymnasium, the person is in the presence of->
2./>
(60/h) corresponds to the average level of resting/passive activity (+)>
=0.5 m 3 And/h), which may be obtained according to the common general knowledge in the art.
S2: determining the number of people who are infected indoors
Initial Virus production->
And viral attenuation RateγThe method comprises the steps of carrying out a first treatment on the surface of the Calculating infection probability->
；
Wherein:
is the number of people easy to be infected in the room, +.>
For the number of cases infected by exposure to virus particles in the room, the air-exposed virus particles are exposed to the air>
Representing the initial rate of quantum generation at the onset of symptoms, < >>
Is the metabolic intensity coefficient of the indoor environment, +.>
Is the total exposure time; />
Time since symptoms occurred for the person who is indoor; />
The number of people with masks in the room is equal to the ratio +.>
The filtering efficiency of the mask is achieved;γa decay rate indicative of a pathogen accumulated in the respiratory tract of the susceptible individual; />
Is the lung respiration rate of the indoor person.
S3: calculating indoor required fresh air quantity;
the calculation of the fresh air volume is classified into the following cases according to the relationship between the total indoor population and the number of indoor infected population.
If it is
>0, according to infection probability and basic reproduction number of virus +.>
Limiting conditions which need to be controlled within 1, and calculating indoor minimum required fresh air quantity +.>
：/>
Wherein:
indicating the total number of people in the room.
When (when)
When less than or equal to 0, the following cases are roughly classified:
1. the total indoor number is 0, the number of the infected persons is also 0, namely, the infected persons are transferred to the indoor without the infected persons, the purpose of ventilation is to remove residual viruses in indoor air, and ventilation is carried out according to the lowest fresh air design standard in a normal period;
2、
i.e. the indoor personnel are infected or the indoor environment is a special area such as ward, etc., the system is openedThe purpose of the wind is to ventilate and dilute the virus produced by the infected person, and provide fresh air for indoor personnel according to the volume of 60m 3 The ventilation is carried out or the maximum ventilation measure is adopted according to the h/person standard, and meanwhile, the necessary virus disinfection measure is carried out to avoid virus diffusion;
3、
and->
At the moment, the number of the indoor infected persons is more than that of the easily infected persons, the infected persons are easily infected, at the moment, the indoor uninfected persons should be transferred preferentially, and at the same time, the number of the indoor uninfected persons is 60m 3 The ventilation is carried out by the maximum design of fresh air volume of a standard or fresh air system of/h/person; (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 volume confirmation indoor design air supply volume based on the confirmation of the previous situation
According to indoor design air supply quantity ∈>
And adjusting the opening degree of the air valve.
In some embodiments of the invention, the method further comprises the steps of:
measuring actual air supply quantity of air valve outlet at each moment
The method comprises the steps of carrying out a first treatment on the surface of the Calculating the actual air supply quantity of the outlet of the air valve>
And the indoor design air supply quantity +>
And (3) adjusting the opening degree of the air valve:
wherein:
is to adjust the opening of the rear air valve>
Is at present +.>
Corresponding air valve opening degree, < >>
Is a proportion control coefficient, and the control coefficient is a proportion control coefficient,
is an integral control coefficient.
In the unsteady state, the actual air supply amount of the air valve outlet at each time
Is a time-varying value, and the indoor design air supply quantity at each moment is +.>
May vary with variations in parameters, such as: the total number of people in the room changes, the number of infected people changes, etc. Thus, the adjustment is a dynamic process.
In some embodiments of the invention, if the air valve outlet is actually supplying air
And the indoor design air supply quantity +>
And stopping adjusting the opening of the air valve when the difference is smaller than the set threshold value. In general, if up to->
And->
The difference between the two meets the control requirement, and the control target can be considered to be achieved within 10% generally, namely the ventilation requirement is met. To obtain a roomTarget air valve opening degree of air supply quantity meeting requirement of internal actual air supply quantity>
。
It should be noted that the investigation found that intimate contact with the infected person would lead to a higher risk of contact with the covd-19 virus by short-range droplet propagation. 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. Because the short-distance spray transmission of viruses is not considered in the invention, in practical application, the ventilation control strategy proposed above should be applied together with epidemic prevention measures such as maintaining physical distance.
The method provided by the invention can obtain a more real and reliable minimum fresh air quantity value capable of controlling the infection risk below the safety threshold, and transmits the calculated value to the fresh air system, adjusts the opening degree of a stroke valve of a tail end device of the system installed in an indoor environment, sends the required fresh air quantity into the indoor, and reduces the virus diffusion risk.
The present invention is not limited to the above-mentioned embodiments, and any equivalent embodiments which can be changed or modified by the technical content disclosed above can be applied to other fields, but any simple modification, equivalent changes and modification made to the above-mentioned embodiments according to the technical substance of the present invention without departing from the technical content of the present invention still belong to the protection scope of the technical solution of the present invention.
Claims (8)
1. An intelligent air volume control system for inhibiting the spreading risk of new crown pneumonia is characterized by comprising a fresh air system, a face detection system and a control system;
the fresh air system comprises: 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 a fresh air fan, and the indoor exhaust pipeline is connected with the outdoor exhaust pipeline through a fresh air fan; the indoor fresh air pipeline comprises an indoor air outlet, and the indoor air outlet is provided with: an air valve, an air valve controller and an air flow measuring device; the air valve controller receives a control system instruction to control the opening degree of the air valve;
the face detection system comprises an image acquisition device, a control system and a mask, wherein the image acquisition device is arranged at an indoor door and is communicated with the control system and 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 masks in indoor personnel based on the images acquired by the face detection system; the control system further calculates the minimum required fresh air quantity, and the fresh air quantity corresponds to the indoor design air supply quantity;
the control system is configured to calculate an indoor demand fresh air volume:
if N-2I>0, calculating the minimum required fresh air quantity Q according to the following method min ：
Wherein: i is the number of people infected in the room, q 0 Representing initial virus quantum generation rate when symptoms occur, wherein m is metabolic intensity coefficient of indoor environment, p is lung respiration rate of indoor personnel, alpha is indoor number of people with masks, beta is mask filtration efficiency, and T is total exposure time of the easily infected people in virus environment; t is the time since symptoms occurred in the infected person; gamma represents the rate of attenuation of pathogens accumulated in the respiratory tract of a susceptible person; n represents the total indoor number of people, and the air valve controller controls the opening of the air valve based on the minimum required fresh air quantity;
if N-2I is less than or equal to 0 and the total indoor number is 0, the number of infected persons is also 0, and ventilation is carried out according to the lowest fresh air design standard in the normal period;
if N-2I is less than or equal to 0, and N=I, or I<N is less than or equal to 2I according to 60m 3 Ventilation is carried out or maximum ventilation measures are taken according to the/h/person standard;
indoor design air supply quantity q is confirmed based on indoor demand fresh air quantity * According to indoor design air quantity q * Adjusting the opening of the air valve to obtain the requiredIs fed into the room so that the risk of viral transmission is controlled within acceptable thresholds.
2. The intelligent air volume control system for inhibiting propagation risk of new crown pneumonia according to claim 1, wherein an air volume measuring device is further arranged at the indoor air outlet and is used for detecting actual air volume at the air outlet of the air valve; the control system further adjusts the opening of the air valve based on the difference value between the indoor actual air supply quantity measured at the air outlet of the air valve and the fresh air supply quantity corresponding to the indoor design.
3. The intelligent air volume control system for inhibiting the risk of transmission of new coronaries pneumonia according to claim 1, wherein the face detection system further comprises a temperature sensing device for detecting the body temperature of a person entering the room.
4. An intelligent air volume control method for inhibiting the spreading risk of new coronaries pneumonia is characterized by comprising the following steps:
s1: counting the total number N of indoor personnel and the occupancy rate alpha of the personnel wearing the mask, and determining the metabolic intensity coefficient m and the lung respiration rate p of the human body of the indoor personnel;
s2: determining initial virus quantum generation rate q of indoor infection number I and symptom occurrence 0 Attenuation rate gamma of pathogens accumulated in the respiratory tract of the susceptible person; calculating infection probability P m ；
Wherein: s is the number of people who are easy to infect in the room, C is the number of cases of infection caused by exposure to virus particles in the air in the room, m is the metabolic intensity coefficient of the indoor environment, and T is the total exposure time of the people who are easy to infect in the room in the virus environment; t is the time since symptoms occurred in the initial infected person; alpha is the indoor number of people with the mask, beta is the mask filtering efficiency, and gamma represents the attenuation rate of pathogens accumulated in the respiratory tract of the person easy to be infected; p is the pulmonary respiration rate of the person in the room;
n is the number of pathogen quanta truly inhaled by the infected person:
n＝m t ·(1-αβ)；
m t indicating the number of pathogens in the host over a period of time;
s3: calculating indoor required fresh air quantity;
if N-2I>0, according to infection probability and basic reproduction number R of virus 0 Limiting conditions which need to be controlled within 1, and calculating indoor minimum required fresh air quantity Q min ：
Controlling the opening of the air valve based on the minimum required fresh air quantity;
if N-2I is less than or equal to 0 and the total indoor number is 0, the number of infected persons is also 0, and ventilation is carried out according to the lowest fresh air design standard in the normal period;
if N-2I is less than or equal to 0, and N=I, or I<N is less than or equal to 2I according to 60m 3 Ventilation is carried out or maximum ventilation measures are taken according to the/h/person standard;
s4: indoor design air supply quantity q is confirmed based on indoor demand fresh air quantity * According to indoor design air quantity q * Adjusting the opening of the air valve; the required fresh air volume is fed into the room so that the risk of viral transmission is controlled within acceptable thresholds.
5. The intelligent air volume control method for inhibiting the propagation risk of new coronaries pneumonia according to claim 4, further comprising the steps of:
measuring the actual air quantity q of the outlet of the air valve t ；
Calculating the actual air quantity q of the outlet of the air valve t And indoor designAir supply quantity
And (3) adjusting the opening degree of the air valve:
wherein: θ t′ Is to adjust the opening degree of the rear air valve theta t Is the current q t Corresponding air valve opening degree K P Is a proportional control coefficient, K I Is an integral control coefficient.
6. The intelligent air volume control method for inhibiting the propagation risk of new coronaries pneumonia according to claim 5, wherein the method comprises the following steps: if the actual air quantity q is supplied from the outlet of the air valve t And the indoor design air supply quantity
And stopping adjusting the opening of the air valve when the difference is smaller than the set threshold value.
7. The intelligent air volume control method for inhibiting the propagation risk of new coronaries pneumonia according to claim 4, wherein the method comprises the following steps: in step S3, the total indoor population is updated according to the detection result of the face detection system.
8. The intelligent air volume control method for inhibiting the propagation risk of new coronaries pneumonia according to claim 4, wherein the method comprises the following steps:
for the family: the metabolic intensity coefficient m of the indoor environment is 1;
for malls, stations, airports: the metabolic intensity coefficient m of the indoor environment is 1.5;
for gymnasiums: the metabolic intensity coefficient m of the indoor environment is 2.
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