KR102156121B1 - Ventilation alarm device for indoor space - Google Patents

Abstract

The ventilation notification apparatus of the present invention includes: an information acquisition unit for acquiring indoor space information and personnel information; A carbon dioxide concentration calculator configured to calculate an amount of carbon dioxide generated by indoor personnel and an amount of ventilation in a closed state, and calculate a carbon dioxide concentration according to time of the indoor space from the amount of carbon dioxide generation and ventilation; And a notification control unit that outputs a ventilation warning when the calculated indoor carbon dioxide concentration exceeds a predetermined reference value.

Description

Ventilation notification device for indoor space {VENTILATION ALARM DEVICE FOR INDOOR SPACE}

The present invention relates to a ventilation notification device for an indoor space, and more particularly, to a ventilation notification device capable of notifying the need for ventilation and completion of ventilation after opening based on the indoor carbon dioxide concentration. It is suitable for a classroom environment where a large number of people perform tasks of similar intensity.

The quality of the air that humans breathe is the most important factor in human health. As humans spend about 80% of the day living indoors, interest in indoor air quality is increasing. Formaldehyde generated in buildings or indoor fine dust, carbon dioxide, radon, etc. degrade indoor air quality.

In order to manage indoor air quality, the government has enacted and implemented the Indoor Air Quality Management Act for multi-use facilities such as public places, and is managed using ventilation or air purifiers.

Ventilation is the most reliable way to improve indoor air quality, and CO ₂ concentration, a representative air pollutant, is used as an indicator of ventilation.

The indoor air quality management in the classrooms of the school is to be 21.6 m ³ for 1 hour per person in accordance with the ventilation of Annex 2 of Article 3, Paragraph 1, Item 1 of the School Health Act, and the concentration of CO _{2 in the} classroom is 1000 ppm for natural ventilation. Try to keep the following. In order to satisfy the ventilation conditions according to the School Health Act, natural ventilation or mechanical ventilation is used in parallel, and recently, a system air conditioner with a filter inserted is also used. However, the mechanical ventilation/air cleaning method described above is often not provided due to high facility costs.

As a method of ventilation, a heat exchange type forced ventilation device and a fan type ventilation system having a relatively simple structure can be operated to save energy, but the simplest and most efficient ventilation system is an open-open ventilation system that opens a window.

In particular, in the case of schools, classes are taught for a minimum of 1 hour to a maximum of 2 hours with windows and doors closed for cooling, heating and noise shielding during class hours, so small classrooms without mechanical ventilation do not provide natural ventilation. Otherwise, there is a problem that the indoor CO ₂ concentration easily rises above the reference value.

Korean Patent Publication No. 10-2010-0131673

An object of the present invention is to provide a ventilation notification device for an indoor space that can effectively ventilate an indoor space through an open window method.

An object of the present invention is to provide a ventilation notification device for an indoor space capable of indicating an accurate opening and closing time based on a carbon dioxide concentration.

A ventilation notification device according to an aspect of the present invention includes: an information acquisition unit that acquires indoor space information and personnel information; A carbon dioxide concentration calculator configured to calculate an amount of carbon dioxide generated by indoor personnel and an amount of ventilation in a closed state, and calculate a carbon dioxide concentration according to time of the indoor space from the amount of carbon dioxide generation and ventilation; And a notification control unit that outputs a ventilation warning when the calculated indoor carbon dioxide concentration exceeds a predetermined reference value.

Here, the information acquisition unit may include an input unit for receiving volume information and personnel information of the indoor space from a user; And a communication unit for receiving outdoor environment information from an external device.

Here, as the indoor space information, one or more of the floor area of the indoor space, the height of the indoor space, the open area of the ventilated window, the number of windows, and the indoor temperature are reflected. , Check-out time, average health level of personnel, and expected indoor activity level of personnel are reflected, and as the outdoor environment information, one or more of the average wind speed around the indoor space and the outdoor temperature around the indoor space may be reflected. .

Here, the notification control unit may output a ventilation warning before a predetermined ventilation preparation time in consideration of a time required for ventilation.

Here, the carbon dioxide concentration calculator may calculate the carbon dioxide concentration in the indoor space according to the following equation.

Qm is the amount of CO ₂ generated, Qv is the total leakage rate, C(t) is the carbon dioxide concentration,

P is the indoor pressure, M is the molecular weight of CO ₂ , C ₀ is the outdoor CO ₂ concentration,

V is the volume of the room, Ci is the initial CO ₂ concentration, R is the ideal gas constant,

T is the room temperature, k is the non-ideal mixing factor constant

Here, a carbon dioxide concentration sensor for directly sensing the carbon dioxide concentration of indoor air may be further included.

Here, a parameter for compensating the slope parameter of the equation for calculating the carbon dioxide concentration by comparing the measured value of the carbon dioxide concentration sensor at a specific point in time and the calculated value of the carbon dioxide concentration before the specific point by a delay time of the carbon dioxide concentration sensor It may further include a correction unit.

Here, the notification control unit may alert the need for ventilation when one of the two concentration values generated by the carbon dioxide concentration sensor and the indoor carbon dioxide concentration calculator according to the equation exceeds a reference value.

If the ventilation notification device for the indoor space according to the idea of the present invention having the above-described configuration is implemented, there is an advantage of effectively ventilating the indoor space at low cost.

The ventilation notification device for an indoor space of the present invention has an advantage of preventing energy waste while increasing ventilation efficiency by notifying an accurate opening and closing timing based on a carbon dioxide concentration.

The ventilation notification device for an indoor space of the present invention can create a comfortable indoor air quality at a low cost, since it is possible to know when to open and close a window if a natural ventilation alarm system is introduced through a window through the natural ventilation alarm system.

Unlike the conventional indoor air quality measurement sensor, the ventilation notification device for an indoor space of the present invention predicts the indoor CO ₂ generation amount and the indoor CO ₂ concentration due to leakage, thereby supporting natural ventilation in a preventative dimension.

Since the ventilation notification device for an indoor space of the present invention can directly configure a user environment, it can be applied to most indoor environments where a room size is not too large. In this way, by maintaining the indoor CO ₂ concentration below 1000 ppm, a healthy and pleasant indoor environment can be created.

The ventilation notification device for an indoor space of the present invention can also calculate the concentration over time of the way in which toxic substances other than CO ₂ are leaked by changing only the sensor and material information, and calculates how much ventilation speed is required. In this way, it can be applied to various engineering fields and safety.

1 is a block diagram showing a ventilation notification device for an indoor space according to an embodiment of the present invention.
2 is a conceptual diagram showing a One-box-Model when air is exchanged only from an indoor space to a window.
3 to 5 are graphs showing measured values of CO ₂ concentration and C(t) in the same closed classroom measured on different dates.
Figure 6 is a graph showing the CO ₂ concentration changes due to ventilation in accordance with the CO ₂ concentration of one when opened the window if the temperature difference between indoor and outdoor.
Figure 7 is a graph showing the CO ₂ concentration changes due to ventilation in accordance with the CO ₂ concentration when the open one when the temperature difference between indoor and outdoor windows is zero.
8 is a graph showing the change in the concentration of CO ₂ in the lecture room according to the concentration of CO ₂ from the opening of the window according to the number of windows.

Hereinafter, a specific embodiment for carrying out the present invention will be described with reference to the accompanying drawings.

In describing the present invention, terms such as first and second may be used to describe various elements, but the elements may not be limited by terms. The terms are only for the purpose of distinguishing one component from other components. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

When a component is connected to or is referred to as being connected to another component, it can be understood that it may be directly connected or connected to the other component, but other components may exist in the middle. .

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions may include plural expressions unless the context clearly indicates otherwise.

In the present specification, terms such as include or include are intended to designate the existence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and one or more other features or numbers, It may be understood that the presence or addition of steps, operations, components, parts, or combinations thereof, does not preclude the possibility of preliminary exclusion.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

1 is a block diagram illustrating a ventilation notification device for an indoor space according to an embodiment of the present invention.

The ventilation notification device 100 for the illustrated indoor space includes: an information acquisition unit for obtaining indoor space information and personnel information; A carbon dioxide concentration calculator 160 for calculating the amount of carbon dioxide generated by indoor personnel and the amount of ventilation in a closed state, and calculating a carbon dioxide concentration according to time of the indoor space from the amount of carbon dioxide generation and ventilation; And a notification controller 180 for outputting a ventilation warning when the calculated indoor carbon dioxide concentration exceeds a predetermined reference value.

The illustrated information acquisition unit includes: an input unit 110 for receiving volume information and personnel information of the indoor space from a user; And a communication unit 120 for receiving outdoor environment information from an external device.

As the indoor space information, one or more of a floor area of an indoor space, a height of an indoor space, an open area of a window capable of ventilation, a number of windows, and an indoor temperature may be reflected. Instead of the floor area of the indoor space and the height of the indoor space, the volume of the indoor space may be directly input, and the ventilation notification device may further include a temperature sensor for obtaining the indoor temperature.

As the number of personnel, at least one of the number of persons, a check-in time, a departure time, an average health level of the personnel, and an expected indoor activity level of the personnel may be reflected.

As the outdoor environment information, one or more of an average wind speed around an indoor space and an outdoor temperature around an indoor space may be reflected.

For example, the input unit 110, through a user input device such as a touch screen, a keyboard, etc., from the user, the floor area of the indoor space, the height of the indoor space, the open area of the ventilation window, the number of windows, the number of people, and One or more of the time, departure time, average age of personnel, and indoor activity level of personnel can be input.

For example, the communication unit 120 may include a wired/wireless communication module such as a Wi-Fi module or a Bluetooth module capable of performing data communication with an external server (such as an indoor space management server or a weather information providing server).

For example, the communication unit 120 may provide a ventilation area, the number of windows, the number of people, the time of entering, the time of leaving, and the time of leaving the window that can be ventilated from an external server (such as an indoor space management server or a weather information providing server). One or more of the average age, the indoor activity level of the personnel, the average wind speed around the indoor space, and the outdoor temperature around the indoor space can be input.

The same information may be input through the input unit 110 or through the communication unit depending on the implementation. The more information input through the input unit 110 is, the more information the user manually inputs, so user convenience is not reduced. However, since the degree of connection between the ventilation notification device and an external server is low, implementation is easy and overall system cost including the external server is lowered.

On the other hand, the more information input through the communication unit 120 is, the higher the user convenience, but the degree of connection between the ventilation notification device and the external server is high, making implementation difficult and the overall system cost including the external server increases.

The illustrated carbon dioxide concentration calculator 160 calculates the indoor carbon dioxide concentration over time according to the obtained indoor space information and personnel information. That is, the carbon dioxide concentration at that time point is predicted for successive times.

The carbon dioxide concentration calculator 160 calculates the carbon dioxide concentration of the indoor space according to a predetermined mathematical process using the indoor space information and the person information as input variables, which will be described later.

Depending on the implementation, the ventilation notification device 100 may further include a carbon dioxide concentration sensor 140 that directly senses the carbon dioxide concentration of indoor air.

However, in general, the carbon dioxide concentration sensor is accurate in the relative value of the sensing values, while the accuracy of the absolute value of the concentration sensing is low. In addition, there is a difference between the concentration of carbon dioxide in the area where the sensor is located in the target indoor space and the concentration of the entire indoor space.

If only the carbon dioxide concentration sensor value is used, an error may be caused by the reaction speed of the carbon dioxide concentration sensor (i.e., sensing delay time), and it is limited to the carbon dioxide concentration for the area where the sensor is located in the target indoor space. Concentrations and differences may also occur. In addition, in the case of a relatively inexpensive small sensor, the superiority and inferiority of the concentration sensing values are fairly accurately indicated, but the accuracy of the absolute value of the sensed concentration is poor.

Therefore, in the present invention, rather than using the carbon dioxide concentration sensor as a main basis for ventilation notification, it is used for real-time correction of the concentration calculation algorithm in calculating the indoor carbon dioxide concentration according to the above-described mathematical process. Alternatively, the sensing value of the carbon dioxide concentration sensor and the calculated value of the indoor carbon dioxide concentration may be equally applied in parallel.

In the former case, the ventilation notification device 100 compares the measured value of the carbon dioxide concentration sensor 140 at a specific point in time and the calculated value of the carbon dioxide concentration at a point before the specific point by a delay time of the carbon dioxide concentration sensor 140 , It may further include a parameter correction unit 150 for correcting the slope parameter of the equation for calculating the carbon dioxide concentration.

For example, the parameter correction unit 150 obtains a carbon dioxide concentration sensing value at two different adjacent viewpoints from the carbon dioxide concentration sensor 140, and the respective viewpoints from the carbon dioxide concentration calculator 160 With respect to the carbon dioxide concentration sensor 140 obtains the carbon dioxide concentration calculated values of the previous time as much as the delay time. The parameter correction unit 150 corrects a parameter for determining a slope based on the two carbon dioxide concentration calculation values by comparing the slope based on the two carbon dioxide concentration sensing values and the two carbon dioxide concentration calculation values. do.

In the latter case, the notification controller 180 may alert the need for ventilation when one of the 2 concentration values generated by the carbon dioxide concentration sensor 140 and the indoor carbon dioxide concentration calculation unit according to the equation exceeds a reference value. .

Depending on the implementation, the notification controller 180 may determine whether or not the carbon dioxide concentration sensor 140 is closed from a relatively rapid drop. In other words, when the window is opened and ventilation proceeds very quickly and the carbon dioxide concentration sensor value drops sharply, it is possible to notify that the window may be closed again.

Depending on the implementation, the notification controller 180 may visually output ventilation necessary information to a display device or a light emitting device, or audibly output ventilation necessary information to a speaker or the like.

Depending on the implementation, the notification control unit 180 may visually/audibly output ventilation completion information when ventilation is performed by opening, as well as the ventilation necessary information.

The American Society for Air Conditioning, Heating, and Air Conditioning has suggested the concentration of indoor CO ₂ as an indicator of ventilation. When the indoor carbon dioxide concentration is less than 800 ppm, it can be said that ventilation is sufficiently performed, and 1000 ppm is suggested as the upper limit of the CO ₂ concentration that can feel comfortable. Therefore, if the indoor CO ₂ concentration is kept below 1000 ppm, the indoor can be said to be comfortable. Reflecting this, the notification control unit may set the ventilation reference ppm to one of 1600 to 1100 ppm of carbon dioxide concentration in the indoor space. For example, by setting 1500 ppm as the ventilation reference ppm, a notification may be performed on a point in time when the indoor carbon dioxide concentration is expected to reach 1500 ppm.

The ventilation standard ppm may be determined according to the average health level of personnel present in the indoor space. For example, when the average age of the personnel is in their teens to 30s, the ventilation standard ppm is set to 1600 ppm, in the 40s, 1500 ppm, in the 50s, 1400 ppm, and in the 60s, it is set to 1300 ppm. , In the case of infants or over 70s, it can be set to 1100 ppm.

Depending on the implementation, the notification controller 180 may output a ventilation warning before a predetermined ventilation preparation time in consideration of the time required for ventilation. For example, if it is expected that it will take 5 minutes for one person to stop an activity performed in the indoor space and open a window for ventilation, a notification is given 5 minutes before the time when the indoor carbon dioxide concentration is expected to reach the ventilation standard ppm. Can be done.

Next, a mathematical process for calculating the carbon dioxide concentration in an indoor space will be described using indoor space information and personnel information as input variables. In explaining the above mathematical process, the indoor space will be embodied as a lecture hall in a university campus.

The driving force of natural ventilation is the difference in air density and the difference in pressure caused by wind pressure. That is, when the temperature difference between indoors and outdoors is large or the wind speed outside the building increases, rapid ventilation is achieved. Here, the temperature difference between indoors and outdoors can be easily obtained, but accurate calculation is difficult because wind pressure is affected by the structure and shape of the building. Therefore, it is suggested to use the approximation equation proposed by Sherman et al.

The university's classrooms have a capacity of as many as 100 and as few as 40, and the CO ₂ concentration is measured in small classrooms with around 40, the most vulnerable, and no mechanical ventilation. The lecture room can be assumed to be a One-Box-Model with ventilation through windows, considering that the windows are well mixed.

As for the amount of CO ₂ generated per student per hour, the maximum value of this value is used because the item'sitting and office work' specified in KSF 2603 is the most similar to learning. In addition, the CO ₂ generation amount (Qm) in the One-Box-Model can be calculated as shown in Equation 1 below. Here, P is the indoor pressure, MCO ₂ is the molecular weight of CO ₂ , R is the ideal gas constant, Ti is the room temperature, and N is the number of students.

Leakage refers to a phenomenon in which indoor air is leaked to the outside of a building by extreme winds generated from gaps in a building structure. The leakage rate proposed by Sherman et al. is a geometric average of the following Equation 2, which is the leakage rate due to the temperature difference between indoors and outdoors, and the following Equation 3, which is the leakage rate according to the air velocity, and can be expressed by Equation 4 below. At this time, if you open the window, you can think of the leakage rate as the natural ventilation rate.

In Equations 2 and 3, the effective leakage area Ae is considered as a gap in a closed space, but when the window is opened to provide natural ventilation, it may be considered as the window area. △T is the temperature difference between the indoors and outdoors, and fs is an equation for the neutral zone, and as shown in Equation 5 below, variables related to the building surface area and floor area (R), indoor height (H), indoor temperature (Ti), and acceleration of gravity (g) Calculate as.

Leakage occurs in the enclosed space, and it is difficult to consider the variable (R) for the effective leak area (Ae) and the total surface area and floor area of the building at this time, so 0.0009 times the following equation (6) suggested by NBNL The value multiplied by the floor area (Afloor) is used, and 0.5 is applied for R.

If it is considered that air is exchanged only through the window in the One-box-Model, it can be considered as shown in FIG. 2. At this time, C ₀ and Tout are the outdoor CO ₂ concentration and temperature, V, Tin and Ci are the indoor volume, temperature, and initial CO ₂ concentration, respectively, and can be expressed as Equation 7 below by using the material balance equation.

When Equation 7 is summarized and each term is integrated with respect to concentration and time, it is equal to Equation 8 below, and the carbon dioxide concentration in the classroom over time can be finally expressed as Equation 9 below.

Here, the parameters of Equation 9 are summarized as follows.
C(t) is the concentration of carbon dioxide, Qm is the amount of CO ₂ generated, Qv is the total leakage rate, P is the indoor pressure, M is the molecular weight of CO ₂ , C ₀ is the outdoor CO ₂ concentration, V is the indoor volume, Ci is the initial stage. CO ₂ concentration, R is the ideal gas constant, T is the indoor temperature, and k is the non-ideal mixing factor constant.
And, the unit of each parameter in the embodiment of the present invention is as follows.
The unit of C(t), Ci, C ₀ is ppm, the unit of T is °C, the unit of V is m ³ , the unit of P is N/m ² , and the unit of M is g/mol.

The prediction and analysis of the change in CO ₂ concentration in a closed classroom are as follows.

Through Equation 9, the CO ₂ concentration (C(t)) according to time in a closed lecture room is obtained. (First, the value of the non-ideal mixing factor constant (k) is assumed to be 1.)

The results of comparing C(t) at this time and the values obtained through the experiment are shown in Table 1 below.

The experiment was measured in the same classroom with a volume (V) of 200 m ^{3 and a} floor area (Afloor) of 58 m2 and an interior height (H) of 3.45 m. The correlation coefficients of the measured values were both 0.97 or higher, reflecting the measurement results very well, and both C(t) and the RMSE values of the trend line coincided with a level of 0.9788 or higher. The measured values, trend lines, and graphs of C(t) are shown in FIGS. 3, 4 and 5.

In conclusion, when natural ventilation is possible in the classroom, the volume of the classroom (V), the height of the room (H), the width of a gap or window (Ae), and the CO ₂ concentration at the time of opening (Cin), the number of occupants (N), and the room Knowing the temperature (Tin), the indoor/outdoor temperature difference (△T), and the ambient wind speed (UH), you can plan a ventilation cycle that keeps the CO ₂ concentration in the classroom below 1000 ppm.

The present invention also proposes a method for calculating the ventilation required time according to the situation.

No matter how long ventilation is maintained, the concentration of CO _{2 in the} atmosphere cannot be below the concentration of CO _{2 in the} atmosphere, and since the indoor CO ₂ concentration is 800 ppm when well-ventilated, the CO ₂ concentration (Ci ) Can be considered as 800 ppm. In addition, since the temperature difference is more dominant than the wind speed among the factors that determine the ventilation speed, it is assumed that the wind speed does not work much, and statistically, an average wind speed of 1.67 m/s in the classroom area is used.

When there is a temperature difference between indoors and outdoors, the time required for ventilation is calculated as follows.

According to the School Health Act, the appropriate indoor temperature for classrooms is 18 ~ 28 ℃, and according to the Ministry of Environment, it is recommended that the temperature difference between indoors and outdoors be less than 5 ℃. Therefore, it was calculated on the assumption that the indoor temperature was 21 ℃ and the indoor and outdoor temperature difference was 5 ℃. In this case, as shown in FIG. 6, the indoor CO ₂ concentration becomes 1000 ppm about 3 minutes after the start of the class. When one window with an area (Ae) of 0.84 m ² is opened, the required ventilation time varies depending on the CO ₂ concentration, and it can be seen that it converges to a constant value.

Table 2 below shows the amount of change according to the concentration at the time of opening of FIG. 6. dC(t)/dt means the instantaneous rate of decrease in concentration, and when this value becomes 0, the CO ₂ concentration does not decrease any more because it is in a steady state.

In the above case, it takes about 25 minutes to decrease to the normal concentration of 650 ppm regardless of the concentration at the time of opening the window. However, when the instantaneous concentration decrease rate was less than -0.1 ppm/sec, the concentration decreased by about 10 to 1 ppm as time passed, and there was no significant difference, so it was judged that it was correct to stop ventilation. That is, when the window is opened, the time at the point where dC(t)/dt becomes -0.1 is selected as the required ventilation time.

When there is little or no temperature difference between indoors and outdoors, the time required for ventilation is calculated as follows.

7 shows the change in concentration at the time of opening the increase rate of the indoor CO ₂ concentration when the indoor/outdoor temperature difference is 0. In an extreme situation where there is no temperature difference between indoors and outdoors, since leakage cannot be properly achieved, the indoor CO ₂ concentration rises rapidly as shown in FIG. 7, and it is difficult to maintain the normal CO ₂ concentration below 1000 ppm when the window is opened.

In this case, you can open more windows and keep it below 1000 ppm. 8 is a graph showing a change in concentration when opening 2 to 4 windows of the same area at an indoor CO ₂ concentration of 1500 ppm. Opening more windows means that the size of the effective leak area (Ae) becomes larger, and because the width of the window is different for each classroom, you can measure it yourself.

It should be noted that the above-described embodiments are for the purpose of explanation and not limitation. In addition, those of ordinary skill in the technical field of the present invention will understand that various embodiments are possible within the scope of the technical idea of the present invention.

100: ventilation notification device 110: input unit
120: communication unit 140: carbon dioxide concentration sensor
150: parameter correction unit 160: carbon dioxide concentration calculation unit
180: notification control unit

Claims (8)

An information acquisition unit that acquires indoor space information and personnel information;
A carbon dioxide concentration calculator configured to calculate an amount of carbon dioxide generated by indoor personnel and an amount of ventilation in a closed state, and calculate a carbon dioxide concentration according to time of the indoor space from the amount of carbon dioxide generation and ventilation; And
And a notification control unit for outputting a ventilation warning when the calculated indoor carbon dioxide concentration exceeds a predetermined reference value,
The carbon dioxide concentration calculating unit is a ventilation notification device that calculates the carbon dioxide concentration of the indoor space according to the following equation.

Qm is the amount of CO ₂ generated, Qv is the total leakage rate, C(t) is the carbon dioxide concentration,
P is the indoor pressure, M is the molecular weight of CO ₂ , C ₀ is the outdoor CO ₂ concentration,
V is the volume of the room, Ci is the initial CO ₂ concentration, R is the ideal gas constant,
T is the room temperature and k is the non-ideal mixing factor constant.
The method of claim 1,
The information acquisition unit may include an input unit for receiving volume information and personnel information of the indoor space from a user; And
Communication unit to receive outdoor environment information from external devices
Ventilation notification device comprising a.
The method of claim 2,
As the indoor space information, one or more of the floor area of the indoor space, the height of the indoor space, the opening area of the ventilable window, the number of windows, and the indoor temperature are reflected,
As the number of personnel information, one or more of the number of people, the time of entering, the time of leaving, the average health level of the personnel, and the expected indoor activity level of the personnel are reflected,
A ventilation notification device in which at least one of an average wind speed around an indoor space and an outdoor temperature around an indoor space are reflected as the outdoor environment information.
The method of claim 1,
The notification control unit outputs a ventilation warning before a predetermined ventilation preparation time in consideration of a time required for ventilation.
delete The method of claim 1,
Carbon dioxide concentration sensor that directly senses the carbon dioxide concentration of indoor air
Ventilation notification device further comprising a.
The method of claim 6,
A parameter correction unit that compares the measured value of the carbon dioxide concentration sensor at a specific point in time and the calculated value of the carbon dioxide concentration at a time before the specific point by a delay time of the carbon dioxide concentration sensor, and corrects a slope parameter of an equation for calculating the carbon dioxide concentration
Ventilation notification device further comprising a.
The method of claim 6,
The notification control unit, when one of the two concentration values generated by the carbon dioxide concentration sensor and the indoor carbon dioxide concentration calculation unit according to the equation exceeds a reference value, a ventilation notification device to alert (alarm) the need for ventilation.

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