The content of co2 in the air. When stuffy: Stuffy room and hypercapnia. Plastic windows without valves - a source of elevated CO2 levels in the apartment

Today, especially in Russia, people underestimate the importance of controlling and maintaining a normal level carbon dioxide(CO2) in an apartment (office, school, in any room where we spend at least half an hour). In this article, I would like to talk more about the quality of air in the house:

• about the importance of maintaining the correct level of CO2 in the premises;
• on methods for measuring CO2 levels;
• briefly about the organization right system air ventilation.

Why is it important to control indoor carbon dioxide levels?

A lot has already been said about the importance of maintaining CO2 levels (I advise you to read:,, a thread on the iXBT forum,). But in short: carbon dioxide is released during human breathing (the main source, and with poor ventilation it accumulates in high concentrations in the room. A slight increase in CO2 concentration causes people to feel that the air is stuffy, stuffy. With a more significant increase in concentration, the symptoms become worse: “severe "Head, dizziness, headaches and up to irreversible changes in the human body. The concentration of carbon dioxide is usually measured in ppm (parts per million - parts per million).

The reaction of the body of an adult depending on the level of CO2

Dangerous concentrations of CO2

Why is there a high level of CO2 in the apartment?

There are three main reasons:

• Plastic windows
• Not working hood and absence supply ventilation
• non-compliance sanitary standards — a large number of people in the room.

Plastic windows without valves - a source of elevated CO2 levels in the apartment

Today we love to install plastic windows and are proud that they completely seal the apartment (after all, it will become warm at home!), But we don’t think about the future consequences (especially if there are children at home!). The reason is that modern windows completely block the air flow from the street and thereby block the work natural system ventilation of the apartment, and as a result, the air in the apartment is not updated and the level of CO2 rises. Some install special window valves through which air from the street passes - this is at least some kind of solution.

By the way, the old Soviet windows with rather big gaps were specially designed to provide at least some fresh air!

Hood not working

Often people do not pay attention to the exhaust vents in the kitchen and bathroom. Some even “lay” them during repairs. Sometimes the mesh on the vents is so clogged that it practically stops the ventilation from working. These factors contribute to the deterioration of the air quality in the apartment. Imagine that you and several other people are in one small enclosed space, actively moving, preparing to eat, etc. After some time, if the air is not renewed, it becomes very difficult to be in this space, many pollutants are concentrated in the air, including carbon dioxide. Now imagine that many of us live like this for years after installing plastic windows! And then we wonder where do we / our children get chronic diseases?

To check the quality of work exhaust ventilation in your apartment it is better to turn to professionals. As a rule, a call to the management company with a complaint about poorly functioning ventilation is enough. But, in order to understand whether ventilation is really not working well, it is better to first check it in less accurate, but "improvised" ways. You can do this by bringing a thin strip of paper, a candle or a burning match to the vents, or you can try smoldering incense sticks - they produce a fairly moderate and safe smoke ( Follow the rules fire safety! ). The paper or smoke should be "sucked" by the air flow into the vent. If this does not happen or the air flow is very weak, try opening a window to “depressurize” the apartment. Even if this did not help, then there are problems with ventilation and they must be fixed! IN apartment buildings responsible for ventilation Management Company and in most cases they should be able to restore the ventilation without charging you extra. Perhaps they will convince you that nothing can be done (or to extort payment), that your house has an old and clogged ventilation system - I recommend being more persistent and in case the Criminal Code refuses to correct the ventilation, apply to higher authorities.

There are several excellent forums on the Internet dedicated to the topic of ventilation in the house, there you can find a lot of useful information and ask questions to professionals:

• branch on the forum "City of Masters" http://www.mastercity.ru/forumdisplay.php?f=22

Forced ventilation

If the exhaust ventilation system is working in your house / apartment and you have well-insulated or plastic windows, then I would highly recommend installing forced ventilation to create conditions for natural air purification in the apartment. Today it is not very expensive and the installation does not spoil the repair in your apartment.

I have passive Domvent valves installed, in the near future I will write a separate article about them. A lot of information about supply ventilation can be found on the iXBT forum in this thread.

Non-compliance with sanitary standards

Observe sanitary norms. Even the best-performing ventilation can fail to big amount people in the room. There are some ways to calculate the required influx of fresh air depending on the number of people in the room (of course, they are very conditional, but for a rough estimate they are quite suitable):

• fresh air intake 15 cfm = 25.5 m3/h per person in the room, corresponding to a CO2 concentration level of 1000 ppm
• fresh air intake 20 cfm = 34 m3/h per person in the room, corresponding to a CO2 concentration level of 800 ppm

What to do?

• Control CO2 levels
• Check if the hood works well in your house (and if it works at all)
• Install supply ventilation (passive - valves; or active - breathers with electric motors and air heating)
• If there is no forced ventilation, then it is recommended to ventilate the room (an ineffective method, because getting up at night, especially in winter, to open the window for a few minutes is unlikely to work)

How to measure the level of carbon dioxide?

Today there are a huge number different devices for CO2 measurement. I will give an example of several of them, the most reliable and common.

Sensair K-30

You need skills in programming, soldering and working with microelectronics, but the most versatile in terms of price / quality ratio. I use exactly that. Where to buy in Russia, unfortunately, I did not find and ordered on the website co2meter.com

Connecting the K-30 sensor to Raspberry Pi or Arduino will be discussed in the following articles.

Tim (link)

Cute, in addition to measuring CO2, it can measure humidity and temperature, there are versions with built-in memory for storing measurements. You can buy it in the same place - co2meter.com.

Netatmo

Cute, expensive, comfortable, mega-multifunctional. You can buy in Russia.

Conclusion

I hope in this article I was able to convey the importance of controlling CO2 levels and providing fresh air in rooms where we spend a lot of time. This is your health and the health of your loved ones! In the next series of articles I will talk about how to connect CO2 sensors in single system Smart home and how to properly organize ventilation (with or without automation).

There are common truths that are familiar to any person almost from birth. It is cold in winter and warm in summer. Respiration consumes oxygen and releases carbon dioxide. When a lot of carbon dioxide accumulates in a room, it becomes stuffy, and in order to be more comfortable in the room, it needs to be ventilated. But at the same time, most people tend to underestimate the impact of increased CO2 concentration on health and quality of life. This is what I want to talk about in this article, and also show how the air conditioner affects the air purification process. And at the same time provide an overview of the CO2 level detector, which helps keep indoor air quality under control.

1 Things to know about CO2
2 Technical information
3 Appearance and operating principle
4 measurements
5 Home automation
6 Conclusions

1. What you need to know about CO2

CO2 or carbon dioxide is an integral part of any air mixture, the content of which is measured in parts per million (ppm - parts per million). A conditionally normal level of CO2 in fresh outdoor air is considered to be 400ppm. This figure is not constant and depends on the specific location - for example, in an ecologically clean area with no industry and low population density, the content of carbon dioxide in the atmosphere can be below the average value, and in a densely populated metropolis, and even with industrial enterprises almost certainly above average.

Indoor air is considered to be of good quality if its CO2 content fluctuates within 800ppm. When the concentration of carbon dioxide reaches 1000ppm, many people already have a feeling of stuffiness and lethargy, and 1400ppm is the normal limit according to the recommendations of San Pina.

A dangerous level is 30000ppm - when such a concentration of CO2 is reached, a person's pulse quickens, there is a feeling of nausea and other symptoms of oxygen starvation. The good news is that it is almost impossible to “breathe” such a concentration of carbon dioxide in office and residential premises, even of very poor quality. However, even small excesses of the permissible concentration of CO2 can significantly affect the quality of life. Already at 1000ppm, concentration of attention decreases, a feeling of lethargy appears, the brain begins to process information worse. With CO2 levels above 1400ppm in the office, it becomes difficult to concentrate at work, and at home there will be problems with sleep. The content of CO2 depends, to a greater extent, on the number of people in the enclosed space.

“You can only manage what you can measure,” wrote the founder modern theory management by Peter Drucker. And the first step to managing the indoor microclimate is to start tracking its objective indicators.

This is where Dajet will help us.

2. Technical information

Model Name: CO2 Detector (Mini CO2 Monitor)
CO2 measurement range: 0 - 3000ppm
Temperature measurement range: 0 - 50
Measurement accuracy: ±10% ppm, ±1.5°C
Information output: LCD display, LED indicators
Current consumption: up to 200mA
Additional functions: sound signal excess CO2 concentration

3. Appearance and principle of operation

The CO2 detector is supplied in cardboard box, containing information about the manufacturer and a brief memo on the effect of elevated concentrations of carbon dioxide on human well-being.

Inside is the device itself, instructions in Russian and a USB cable. The detector does not have a built-in battery, so it can only work from an external power source: a computer USB port or a conventional one. charger for smartphone.

The device itself close-up. On the front panel there is a screen and three indicator LEDs that display the averaged measurement results: at a CO2 concentration below 800ppm, a green LED is lit, at 800-1200ppm - yellow, above 1200ppm - red. The values ​​of the indicator action intervals can be changed in the settings.

At all, LED indication turned out to be very informative. No need to approach the device and peer into the current values ​​of the indicators. It can be seen from afar that if the indicator has switched from green to yellow, then the room can already be ventilated, and if it turns red, it is advisable to start airing right now.

On the right side there is a microUSB port and a hole through which air is taken for analysis.

Rear ventilation holes, sticker with technical information and two buttons for setting.

The heart of the device is the ZGm053UK carbon dioxide sensor, which uses NDIR (non-dispersive infrared radiation) technology. infrared radiation): an air stream enters the light guide tube and falls under the radiation infrared lamp, and at the other end of the tube is an infrared detector with an appropriate filter. The more CO2 is contained in the air mixture, the stronger the infrared glow weakens, which allows the sensor to determine the current CO2 concentration.

The cost of NDIR sensors is higher than that of analogues with a different operating principle (electrochemical or electroacoustic), but at the same time they have a long service life and provide more accurate results.

4. Measurements

Now let's test the detector in operation. Place of measurements - Chelyabinsk, two-room apartment in a relatively quiet area, the windows overlook the courtyard.

Experience number 1. Getting to know the instrument

First of all, I measured the concentration of carbon dioxide in the street by placing the detector by an open window on the 4th floor.

Measurements showed 440ppm. The normal level of CO2 in the atmosphere, I remind you, is 400ppm. Well, adjusted for calm weather and living in an industrial metropolis with a traditionally problematic environment, 440ppm can be considered a normal result.

Now let's measure the CO2 level in the apartment itself, having previously ventilated all the rooms well.

It turned out 550ppm. This excellent result, the air is almost like outside.

But, looking ahead, I will say: it is almost impossible to maintain such air quality on an ongoing basis in an apartment that is not equipped with advanced ventilation systems.

Experience number 2. Long measurements

In the course of the review, I have not yet mentioned that the detector not only displays instantaneous values ​​of CO2 concentration, but is also able to work in conjunction with a computer.

If you install a special program, the device will record the level of CO2 concentration and temperature in the room with reference to time and build a graph based on these indicators.

Further measurements will be carried out using this program.

Night with closed window and door. By morning, the CO2 concentration in the room jumps to almost 2000ppm.

Open the window sash for ventilation and look at the graph. In about 40 minutes, the concentration of carbon dioxide drops from 2000ppm to a healthy level of 700ppm.

Evening. The natural noise subsides and the voices of companies resting in the yard become especially audible. They interfere, so I close the window.

In an hour, the CO2 concentration almost doubles, from 700ppm to 1300ppm.

Experience number 3. Daily monitoring

Now let's see how the concentration of CO2 in the room changes during one full day.
Initial data: the same two-room apartment, in which there are from one to three people at the same time. The window in the kitchen is almost always open, windows and balcony door rooms open and close during the day, interior doors are closed for the night.

I ventilate the room well before going to bed, close the window and go to bed.

By midnight, the CO2 concentration is already exceeded, but until five in the morning it remains at a level that can hardly be called satisfactory. Between five and nine in the morning, the CO2 concentration rises to 2000ppm. By the way, this is quite correlated with personal feelings when sleeping with the window closed. Somewhere at 5 am I wake up in a fairly awake state, but since it's still too early, I stay in bed to fill up until the alarm goes off. At the wake of the alarm clock at 7 am, I wake up with a heavy head and in a depressed mood, as if I had not slept all night - by this time the body has already managed to breathe in “bad” air, which affects my well-being.

From 9 to 10 hours - airing. Windows are open in all rooms, the CO2 concentration drops from 2000ppm to 600ppm.

From 10:00 to 15:00 - the windows in the rooms are closed, the window in the kitchen is open. The apartment has 1 person. The CO2 concentration is normal.

From 15:00 to 18:00 - windows are open in all rooms. There are 2 people in the apartment. The CO2 concentration is still normal.

From 18:00 to 21:00 - windows are open in all rooms. There are 3 people in the apartment. The concentration of CO2 begins to increase, the vents no longer save.

From 21 to 22-30 hours - ventilation with open windows. There are 3 people in the apartment. The CO2 concentration returns to normal, but it starts to rise immediately, it is worth closing the windows and leaving only the vents for ventilation.

Now consider another day with a different routine.

At night, the window in the room is open, the CO2 concentration is slightly exceeded, but still does not grow to quite wild values.

From 8 am to 2 pm - there is no one in the apartment, interior doors are open, windows are open in all rooms. The CO2 concentration drops to the level of outdoor air.

From 14:00 to 18:00 - 2 people in the apartment, interior doors are open, windows are open in all rooms. The CO2 concentration is no longer like outside, but within normal limits.

From 18:00 until morning - there are 3 people in the apartment, the interior doors are closed, the windows are open. The CO2 concentration is slightly higher but stable.

Conclusion: if you live alone two-room apartment so you don't have to worry about air quality. It is enough to ventilate the room occasionally. But with two or three inhabitants on the same number square meters to maintain the concentration of carbon dioxide within normal limits, it will be necessary to carry out ventilation almost around the clock.

Experience number 4. CO2 and air conditioning

Now let's see what happens in the room when using the air conditioner.
Initial data: a ventilated room, but it's hot outside, and, accordingly, indoors too.

I close the windows so that the air does not leave, I turn on the air conditioner.

As a result, during an hour of air conditioning operation, the temperature in the room dropped by several degrees, and the concentration of CO2 increased.

The catch is that if you do not leave the premises for Fresh air, then subjectively the air in it is perceived as fresh and of high quality simply due to its coolness. And only the numbers on the device show the real picture.

Air conditioning does not replace ventilation, so sitting all day in a cozy and cool room, you can quietly “breathe” a CO2 concentration of 2000ppm, or even more. This is especially true for offices where several people are in one small room at once. There is a widespread misconception that since a separate air duct is mounted directly to the street for the air conditioner, the air conditioner takes in the street air, cools it inside and releases it into the room. In fact, the air duct serves to eject hot air from the room to the street, that is, it works like an exhaust hood. Moreover, such air conditioners are not found everywhere. A conventional split system “drives” the air in the room in a circle, and cooled refrigerant enters through the pipes.

When using an air conditioner, remember to saturate the room with fresh air.

5. Home automation

At the end of the review, I want to note that the scope of the CO2 detector is not limited to just taking measurements and plotting on a computer.

This device can be used in home automation projects in two different ways.

First way- connection of a power relay to one of the indication LEDs.

The principle of operation is obvious: when the concentration of CO2 in the air rises, the green indicator changes to yellow, while automatically closing electronic key in the relay, which in turn turns on the device connected to the relay (for example, a fan of the supply system).

Second way- software.

Since the detector supports the transfer of data from the sensor to the computer via the USB protocol, it can be implemented in any makeshift system « smart home”, reading the readings from the sensor to the head unit. And already from the head unit, based on the obtained indicators, control other electronics connected to the system.

6. Conclusions

It was interesting to see the real state of the air in my apartment. With the use, it became clearly seen that the existing passive ventilation is ineffective, and if in warm time you can still keep the windows open almost around the clock (although in summer it is not always convenient due to street noise), in winter this is not feasible due to the rapid cooling of the premises. There was a reason to think about the modernization of home ventilation, and about maintaining a healthy microclimate in the room as a whole. In addition, the store has in its assortment, which has a larger display and allows you to measure, in addition to CO2 concentration and temperature, also relative humidity air. 10% discount is available with promo code GT-CO2 for 14 days.

One of the following articles will describe how to make friends with a CO2 detector with a Raspberry Pi microcomputer. Add tags

The problem of excess carbon dioxide in indoor air has been discussed more and more in the last 20 years. New studies are coming out and new data are being published. Do they keep up with them? building codes for the buildings in which we live and work?

The well-being and performance of a person are closely related to the quality of the air where he works and rests. And air quality can be determined by the concentration of carbon dioxide CO2.

Why exactly CO2?

• This gas is everywhere where there are people.
• The concentration of carbon dioxide in the room directly depends on the processes of human life - because we exhale it.
• Exceeding the level of carbon dioxide is harmful to the state of the human body, so it must be monitored.
• An increase in CO2 concentration clearly indicates problems with ventilation.
• The worse the ventilation, the more pollutants are concentrated in the air. Therefore, an increase in carbon dioxide content in the room is a sign that air quality is declining.

IN last years In the professional communities of doctors and building designers, there are proposals to revise the method for determining air quality and expand the list of measured substances. But so far, nothing more visible than the change in CO2 levels has been found.

How do you know if the level of carbon dioxide in a room is acceptable? Experts offer lists of standards, and for buildings different purposes they will be different.

Carbon dioxide standards in residential premises

Designers of multi-apartment and private houses take as a basis GOST 30494-2011 called “Residential and public buildings. Indoor microclimate parameters. This document considers the optimal level of CO2 for human health to be 800 - 1,000 ppm. A mark of 1,400 ppm is the limit for the permissible content of carbon dioxide in the room. If it is higher, then the air quality is considered low.

However, already 1,000 ppm is not recognized as a variant of the norm by a number of studies on the dependence of the state of the body on the level of CO2. Their data indicates that at around 1,000 ppm, more than half of the subjects feel a deterioration in the microclimate: increased heart rate, headache, fatigue and, of course, the notorious "nothing to breathe."

Physiologists consider the normal level of CO2 to be 600 - 800 ppm.

Although some isolated complaints of stuffiness are possible at the indicated concentration.

It turns out that building standards for CO2 levels are in conflict with the conclusions of physiologists. In recent years, it is precisely from the latter that calls have been made more and more loudly to update the permissible limits, but so far things have not gone beyond calls. The lower the CO2 norm that builders are guided by, the cheaper it is. And those who are forced to solve the problem of ventilating the apartment on their own have to pay for this.

Carbon Dioxide Regulations in Schools

The more carbon dioxide in the air, the more difficult it is to focus and cope with the study load. Knowing this, US authorities recommend that schools maintain CO2 levels below 600 ppm. In Russia, the mark is slightly higher: the already mentioned GOST considers 800 ppm or less to be optimal for children's institutions. However, in practice, not only the American, but also the Russian recommended level is a blue dream for most schools.

One of ours showed that more than half of the training time, the amount of carbon dioxide in the air exceeds 1,500 ppm, and sometimes approaches 2,500 ppm! In such conditions it is impossible to concentrate, the ability to perceive information is critically reduced. Other likely symptoms of too much CO2 are hyperventilation, sweating, eye inflammation, nasal congestion, and difficulty breathing.

Why is this happening? The offices are rarely ventilated because open window- these are children with a cold and noise from the street. Even if the school building is equipped with powerful central ventilation, it is usually either noisy or outdated. But the windows in most schools are modern - plastic, airtight, airtight. With a class of 25 people in a room of 50-60 m2 with a closed window, carbon dioxide in the air jumps by 800 ppm in just half an hour.

Carbon dioxide standards in offices

In offices, the same problems are observed as in schools: an increased concentration of CO2 makes it difficult to concentrate. Mistakes are multiplying and productivity is falling.

Standards for the content of carbon dioxide in the air for offices are generally the same as for apartments and houses: 800 - 1,400 ppm is considered acceptable. However, as we have already found out, already 1,000 ppm causes discomfort to every second person.

Unfortunately, in many offices the problem is not solved in any way. Somewhere they simply don’t know anything about it, somewhere the management deliberately ignores it, and somewhere they try to solve it with the help of an air conditioner. A jet of cool air really creates a short-term illusion of comfort, but carbon dioxide does not disappear anywhere and continues to do its "dirty deed".

It may be so that office space built in compliance with all standards, but operated with violations. For example, the employee density is too high. According to building regulations, one person should have from 4 to 6.5 m2 of area. If there are more employees, then carbon dioxide in the air accumulates faster.

Conclusions and Outputs

The problem with ventilation is most acute in apartments, office buildings and children's institutions.
There are two reasons for this:

1. The discrepancy between building codes and sanitary and hygienic recommendations.
The former say: no more than 1,400 ppm CO2, the latter warn: this is too much.

2. Non-compliance with standards during the construction, reconstruction or operation of the building.
The simplest example is the installation of plastic windows that do not allow outside air to pass through and thereby exacerbate the situation with the accumulation of carbon dioxide in the room.

Air is a mixture of gases, in which carbon dioxide (CO2) occupies only the fourth place in terms of quantity, however essential for all living things. Measuring the concentration of carbon dioxide is quite easy, and data on the amount of CO2 allows you to indirectly judge the content of other substances and use this data for air quality analysis. The basic unit of measure for carbon dioxide concentration is ppm.

With a slight increase in CO2 levels, a person feels stuffiness, fatigue, drowsiness, inability to concentrate, loss of attention, irritability, decreased performance, etc.

In closed rooms with insufficient ventilation, a person actively absorbs oxygen (O2), while exhaling a large amount of carbon dioxide, and if a person is not very susceptible to changes in the oxygen content in the air, then changes in the CO2 content are felt by every cell (and this is not a metaphor) due to the fact that the process of gas exchange of O2 and CO2 in the lungs occurs due to passive diffusion through the cell membrane, and the diffusion capacity of CO2 is 25-30 times higher than that of O2, which is why a person is very sensitive to changes in the concentration of CO2 in the air.

The fact that gas exchange in cells proceeds normally only when correct meaning partial pressure CO2 in the blood (PACO2). At the same time, both an increase and a decrease in PA CO2 leads to the fact that the transport of O2 to cells worsens, as well as to many other changes. A simple example: if you hold your breath, then the transport of O2 to the cells in the lungs worsens, but the transport of CO2 does not stop, while initially the desire to take a deep breath causes the increase in PA CO2. This protective function body - a command aimed at returning the PA CO2 level to normal, a warning that something is wrong. Similarly, the body behaves in stuffy rooms with high levels of CO2 - there is a desire to take a deep breath, open a window, go out to breathe on a balcony or street.

As you can see, the most harmful is long-term stay in rooms with high content CO2, that's why Special attention should be given to home ventilation and ventilation of workplaces. At the same time, the most correct and energy-efficient method of air exchange regulation is regulation by a CO2 sensor.

The use of this method of regulation is also the most convenient for the user, since it is not necessary to click switches, turn the regulator, constantly adjusting the air exchange, and even more so switch speeds on the control panel. The user does not interfere with the operation of the ventilation system at all, the unit regulates everything automatically and as accurately as possible, creating an ideal atmosphere in the premises, regardless of constantly changing conditions.

CO2 sensor control options

Please note that there are two types of air exchange control based on the CO2 sensor.

Ventilation by one unit of several rooms

Ventilation of several isolated air volumes, such as apartments, houses, several offices. It is mainly used on the household equipment line CAPSULE and I-VENT, as well as on the supply and exhaust units ZENIT, ZENIT HECO. For each room we need:

• Proportional valve on the supply channel
• Proportional valve on the exhaust duct (If the hood is in each room)
• CO2 sensor for each room or exhaust duct for each room.
• VAV system on the unit (installed by the manufacturer).

When a person enters the room, the CO2 sensor will register an increase in CO2 levels. The motorized proportional valve will regulate the air exchange based on the readings of its own CO2 sensor. This control option will allow you to maintain the air quality in the room as accurately as possible, preventing a feeling of lack of air and without creating excessive air exchange.

An example of the operation of ventilation by CO2 sensors installed in the premises:

There is one person in room 2, and to compensate for the increase in CO2 concentration, it is enough to supply 25 m³/h to the room. In room 1, there are two people, and 75 m³/h must be supplied to compensate. If one person leaves the premises, then in room No. 2 CO2 emission will stop completely, the valve will close, and the ventilation of the room will stop. In room 1, CO2 emissions will decrease and the unit will gradually reduce the air exchange in room 1 to 25 m³/h.

ATTENTION!!!

The use of one CO2 sensor in the exhaust duct is undesirable if there are several rooms. The CO2 sensor will register the total concentration of carbon dioxide and increase the air exchange equally in both rooms. As a result, there is not enough air exchange in the upper room to compensate for the increase in CO2 levels, and an excess amount of air is supplied to the lower room.

Ventilation by one unit of one room

Ventilation of one isolated volume of air, e.g. office, gym, production premises, studio apartments. In this case, we only need a CO2 sensor installed in the exhaust duct (installed by the manufacturer). The air exchange will be automatically adjusted to maintain the required level of CO2, regardless of the change in the number of people in the room, as well as their type of activity.

This control option is mainly used on the industrial line of equipment of the Zenit, Zenit HECO, CAPSULE series and even in i-Vent installations. The use of this system will allow organizing the most energy-efficient ventilation system, with minimal operating costs and fully automatic control.

Example of ventilation operation by CO2 sensors installed in the exhaust duct:

There is one person in the room, and to compensate for the increase in CO2 concentration, it is enough to supply 50 m³/h to the room, as the number of people in the room increases, the recorded level of CO2 increases, and the unit automatically increases the amount of air that needs to be supplied to the room to compensate for the increase in level CO2.

Calculation of the ventilation system for CO2

This is one of the options for calculating the ventilation system, but, unfortunately, it is used quite rarely, since there are not too many systems that can regulate air exchange using a CO2 sensor. To calculate nm, you need to know the following data:

1. Outdoor CO2 concentration.
2. Schedule of stay of people in serviced premises.
3. Type physical activity in serviced premises.
4. Required maintained CO2 level.

The formula for calculating the air exchange to compensate for the emission of CO2 by one person: L=(G×550)/(X2-X1)

• L - air exchange, m3/h;
• X1 - CO2 concentration in the outside (supply) air, ppm;
• X2 - allowable CO2 concentration in the room air, ppm;
• G is the amount of CO2 emitted by one person, l/h;
• 550 - conversion of X1 and X2 values ​​from ppm to g/m3.

Data for G and outdoor CO2 concentration are selected from tables.

An example of calculating an apartment with a number of residents of 3 people.

For these conditions, the Zenit-350 Heco unit will be most suitable.

If you make a schedule for the day, you will be able to see a picture of the change in air exchange during the day, depending on the release of CO2 in the apartment.

As we can see, even according to the average schedule, the schedule of changes in air exchange is very significant, in reality, the system constantly regulates air exchange, having practically no "shelves" on the schedule. At the same time, if the unit is chosen correctly, in this case it is Zenit-350 Heco, then the CO2 value in the apartment will always be unchanged.

*It does not matter for the calculation which type of CO2 unit control is used. This can be either a sensor in the exhaust duct, if it is the ventilation of a studio apartment, or room CO2 sensors together with

In September 2016, the concentration of carbon dioxide in the Earth's atmosphere passed the psychologically significant mark of 400 ppm (parts per million). This makes the plans of developed countries to prevent an increase in temperature on Earth by more than 2 degrees doubtful.

Global warming is an increase in the average temperature climate system Earth. During the period from 1906 to 2005, the average air temperature near the planet's surface increased by 0.74 degrees, and the rate of temperature increase in the second half of the century is about twice as high as for the period as a whole. For all the time of observations, 2015 is considered the hottest year, when all temperature indicators 0.13 degrees higher than in 2014, the previous record holder. IN various parts the globe temperatures vary. Since 1979, temperatures over land have risen twice as much as over the ocean. This is explained by the fact that the air temperature over the ocean grows more slowly due to its large heat capacity.

The movement of carbon dioxide in the atmosphere

Human activities are considered to be the main cause of global warming. Indirect research methods have shown that until 1850, for one or two thousand years, the temperature remained relatively stable, albeit with some regional fluctuations.

Thus, the beginning of climate change almost coincides with the beginning of the industrial revolution in most Western countries. Greenhouse gas emissions are considered to be the main reason today. The fact is that part of the energy that the planet Earth receives from the Sun is re-radiated back into outer space in the form of thermal radiation.

Greenhouse gases hinder this process by absorbing some of the heat and keeping it in the atmosphere.

The addition of greenhouse gases to the atmosphere leads to even greater heating of the atmosphere and an increase in temperature near the surface of the planet. The main greenhouse gases in the Earth's atmosphere are carbon dioxide (CO 2) and methane (CH 4). As a result of the industrial activity of mankind, the concentration of these gases in the air is growing, which leads to annual growth temperature.

Since climate warming threatens literally all of humanity, attempts are made repeatedly in the world to bring this process under control. Until 2012, the main global agreement on countering global warming was the Kyoto Protocol.

It covered more than 160 countries of the world and covered 55% of the world's greenhouse gas emissions. However, after the end of the first stage of the Kyoto Protocol, the participating countries could not agree on further actions. In part, the second stage of the treaty was hampered by the fact that many participants avoid using a budget approach to determine their obligations in relation to CO 2 emissions. CO 2 emission budget - the amount of emissions over a certain period of time, which is calculated from the temperature that participants must not exceed.

According to the decisions taken in Durban, no binding climate agreement will be in place until 2020, despite urgent efforts to reduce gas emissions and reduce emissions. Studies show that at present the only way to provide a "reasonable probability" of limiting warming to 2 degrees (characterizing dangerous climate change) will be to limit the economies of developed countries and their transition to an anti-growth strategy.

And in September 2016, according to the Mauna Loa Observatory, another psychological barrier of CO 2 greenhouse gas emissions was overcome - 400 ppm (parts per million). It must be said that this value was repeatedly exceeded before,

but September is traditionally considered the month with the lowest concentration of CO 2 in the Northern Hemisphere.

This is explained by the fact that green vegetation has time to absorb a certain amount of greenhouse gas from the atmosphere over the summer before the leaves fall from the trees and some of the CO 2 returns. Therefore, if the psychologically important threshold of 400 ppm was exceeded in September, then, most likely, monthly indicators will never be lower than this value.

“Is it possible that in October this year the concentration will decrease compared to September? Completely ruled out

Ralph Keeling of the Scripps Institution of Oceanography in San Diego explains on his blog. “Short-term drops in the concentration level are possible, but the monthly average values ​​will now always exceed 400 ppm.”

Keeling also notes that tropical cyclones can reduce CO 2 levels for a short time. Gavin Schmidt, chief climate scientist, agrees: “At best, you can expect some kind of balance, and CO 2 levels will not rise too quickly. But, in my opinion, CO 2 will never fall below 400 ppm again.”

According to the forecast, by 2099 the concentration of CO 2 on Earth will be 900 ppm, which will be about 0.1% of the entire atmosphere of our planet. As a result, average daily temperatures in cities like Jerusalem, New York, Los Angeles and Mumbai will be close to +45°C. In London, Paris and Moscow, temperatures will exceed +30°C in summer.