2018-05-15

IN Soviet time in textbooks on ventilation and air conditioning, as well as among design engineers and adjusters, the i-d-diagram was usually referred to as the "Ramzin diagram" - in honor of Leonid Konstantinovich Ramzin, a prominent Soviet heating engineer whose scientific and technical activity was multifaceted and covered a wide range scientific issues of heat engineering. At the same time, in most Western countries, it has always been called the "Mollier diagram" ...

i-d- diagram as a perfect tool

June 27, 2018 marks the 70th anniversary of the death of Leonid Konstantinovich Ramzin, a prominent Soviet heat engineer, whose scientific and technical activities were multifaceted and covered a wide range of scientific issues of heat engineering: the theory of designing thermal power and power plants, aerodynamic and hydrodynamic calculation of boiler plants, combustion and radiation of fuel in furnaces, the theory of the drying process, as well as the solution of many practical problems, for example, the efficient use of coal from Moscow region as fuel. Before Ramzin's experiments, this coal was considered inconvenient for use.

One of Ramzin's many works was devoted to the mixing of dry air and water vapor. Analytical calculation of the interaction of dry air and water vapor is a rather complex mathematical problem. But there is i-d- diagram. Its use simplifies the calculation in the same way as i-s- the diagram reduces the complexity of calculating steam turbines and other steam engines.

Today, the work of an air conditioning designer or commissioning engineer is hard to imagine without the use of i-d- diagrams. It can be used to graphically represent and calculate air treatment processes, determine the capacity of refrigeration units, analyze in detail the process of drying materials, determine the state of humid air at every stage of its processing. The diagram allows you to quickly and visually calculate the air exchange of a room, determine the need for air conditioners in cold or heat, measure the condensate flow rate during the operation of the air cooler, calculate the required water flow rate during adiabatic cooling, determine the dew point temperature or wet bulb temperature.

In Soviet times, in textbooks on ventilation and air conditioning, as well as among design engineers and adjusters i-d- the diagram was commonly referred to as the "Ramzin diagram". At the same time, in a number of Western countries - Germany, Sweden, Finland and many others - it has always been called the "Mollier diagram". Over time, technical capabilities i-d- charts are constantly expanded and improved. Today, thanks to it, calculations are made of the states of humid air under conditions of variable pressure, air oversaturated with moisture, in the area of ​​fogs, near the ice surface, etc. .

First message about i-d- diagram appeared in 1923 in one of the German magazines. The author of the article was a well-known German scientist Richard Mollier. Several years passed, and suddenly in 1927 an article appeared in the journal of the All-Union Thermal Engineering Institute, Professor Ramzin, director of the institute, in which he, practically repeating i-d- diagram from a German journal and all the analytical calculations cited there by Mollier, declares himself the author of this diagram. Ramzin explains this by the fact that back in April 1918, in Moscow, at two public lectures at the Polytechnic Society, he demonstrated a similar diagram, which at the end of 1918 was published by the Thermal Committee of the Polytechnic Society in lithographed form. In this form, writes Ramzin, the diagram was widely used by him in MVTU in 1920 as study guide while lecturing.

Modern admirers of Professor Ramzin would like to believe that he was the first to develop the diagram, so in 2012 a group of teachers from the Department of Heat and Gas Supply and Ventilation of the Moscow state academy public utilities and construction tried to find documents in various archives confirming the facts of primacy stated by Ramzin. Unfortunately, no clarifying materials for the period 1918-1926 were found in the archives accessible to teachers.

True, it should be noted that the period of Ramzin's creative activity fell on a difficult time for the country, and some rotoprint publications, as well as draft lectures on the diagram, could be lost, although the rest of his scientific developments, even handwritten ones, were well preserved.

None of the former students of Professor Ramzin, except for M. Yu. Lurie, also left no information about the diagram. Only engineer Lurie, as the head of the drying laboratory of the All-Union Thermal Engineering Institute, supported and supplemented his boss, Professor Ramzin, in an article published in the same VTI magazine for 1927.

When calculating the parameters of humid air, both authors, L. K. Ramzin and Richard Mollier, believed with a sufficient degree of accuracy that the laws of ideal gases can be applied to humid air. Then, according to Dalton's law, the barometric pressure of moist air can be represented as the sum of the partial pressures of dry air and water vapor. And the solution of the Klaiperon system of equations for dry air and water vapor allows us to establish that the moisture content of air at a given barometric pressure depends only on the partial pressure of water vapor.

The diagram of both Mollier and Ramzin is built in an oblique coordinate system with an angle of 135° between the axes of enthalpy and moisture content and is based on the equation for the enthalpy of moist air related to 1 kg of dry air: i = i c + i P d, Where i c and i n is the enthalpy of dry air and water vapor, respectively, kJ/kg; d— air moisture content, kg/kg.

According to Mollier and Ramzin, relative humidity is the ratio of the mass of water vapor in 1 m³ of moist air to the maximum possible mass of water vapor in the same volume of this air at the same temperature. Or, roughly, relative humidity can be represented as the ratio of the partial pressure of vapor in air in an unsaturated state to the partial pressure of vapor in the same air in a saturated state.

Based on the above theoretical assumptions in the system of oblique coordinates, an i-d-diagram was compiled for a certain barometric pressure.

Enthalpy values ​​are plotted along the ordinate axis, values ​​of moisture content of dry air are plotted along the abscissa axis, directed at an angle of 135 ° to the ordinate, and lines of temperature, moisture content, enthalpy, relative humidity are plotted, and a scale of partial pressure of water vapor is given.

As stated above, i-d- the diagram was drawn up for a certain barometric pressure of humid air. If the barometric pressure changes, then the moisture content and isotherm lines on the diagram remain in their places, but the values ​​of the relative humidity lines change in proportion to the barometric pressure. So, for example, if the barometric air pressure is halved, then on the i-d-diagram on the line of relative humidity of 100%, humidity 50% should be written.

The biography of Richard Mollier confirms that i-d-diagram was not the first calculation diagram he compiled. He was born on November 30, 1863 in the Italian city of Trieste, which was part of the multinational Austrian Empire, ruled by the Habsburg Monarchy. His father, Edouard Mollier, was first a ship engineer, then became the director and co-owner of a local machine-building factory. Mother, nee von Dyck, came from an aristocratic family from the city of Munich.

After graduating from the gymnasium in Trieste with honors in 1882, Richard Mollier began to study first at the university in the city of Graz, and then transferred to the Munich Technical University where he paid much attention to mathematics and physics. His favorite teachers were professors Maurice Schroeter and Carl von Linde. After successfully completing his studies at the university and a short engineering practice at his father's enterprise, Richard Mollier in 1890 at the University of Munich was enrolled as an assistant to Maurice Schroeter. His first scientific work in 1892 under the direction of Maurice Schroeter was related to the construction of thermal diagrams for a course in machine theory. Three years later, Mollier defended his doctoral dissertation on the entropy of steam.

From the very beginning, Richard Mollier's interests were focused on the properties of thermodynamic systems and the ability to reliably represent theoretical developments in the form of graphs and diagrams. Many colleagues considered him a pure theorist, since instead of conducting his own experiments, he relied in his research on the empirical data of others. But in fact, he was a kind of "link" between theorists (Rudolf Clausius, J. W. Gibbs, etc.) and practical engineers. In 1873, Gibbs, as an alternative to analytical calculations, proposed t-s- a diagram in which the Carnot cycle turned into a simple rectangle, which made it possible to easily assess the degree of approximation of real thermodynamic processes in relation to ideal ones. For the same diagram in 1902, Mollier suggested using the concept of "enthalpy" - a certain state function, which at that time was still little known. The term "enthalpy" was previously at the suggestion of the Dutch physicist and chemist Heike Kamerling-Onnes (Laureate Nobel Prize in Physics in 1913) was first introduced into the practice of thermal calculations by Gibbs. Like "entropy" (a term coined in 1865 by Clausius), enthalpy is an abstract property that cannot be directly measured.

The great advantage of this concept is that it allows one to describe the change in the energy of a thermodynamic medium without taking into account the difference between heat and work. Using this state function, Mollier proposed in 1904 a diagram reflecting the relationship between enthalpy and entropy. In our country it is known as i-s- diagram. This diagram, while retaining most of the virtues t-s-diagrams, gives some additional features, allows you to surprisingly simply illustrate the essence of both the first and second laws of thermodynamics. Investing efforts in a large-scale reorganization of thermodynamic practice, Richard Mollier developed a whole system of thermodynamic calculations based on the use of the concept of enthalpy. As a basis for these calculations, he used various graphs and diagrams of the properties of steam and a number of refrigerants.

In 1905, the German researcher Müller, for a visual study of the processing of moist air, built a diagram in a rectangular coordinate system from temperature and enthalpy. Richard Mollier in 1923 improved this diagram by making it oblique with the axes of enthalpy and moisture content. In this form, the diagram has practically survived to this day. During his life, Mollier published the results of a number of important studies on thermodynamics, brought up a whole galaxy of outstanding scientists. His students, such as Wilhelm Nusselt, Rudolf Planck and others, made a number of fundamental discoveries in the field of thermodynamics. Richard Mollier died in 1935.

L. K. Ramzin was 24 years younger than Mollier. His biography is interesting and tragic. It is closely associated with political and economic history our country. He was born on October 14, 1887 in the village of Sosnovka Tambov region. His parents, Praskovya Ivanovna and Konstantin Filippovich, were teachers at the Zemstvo school. After graduating from the Tambov gymnasium with a gold medal, Ramzin entered the Higher Imperial Technical School (later MVTU, now MSTU). While still a student, he takes part in scientific papers under the guidance of Professor V. I. Grinevetsky. In 1914, having completed his studies with honors and received a diploma in mechanical engineering, he was left at the school for scientific and teaching work. Less than five years later, the name of L. K. Ramzin began to be mentioned on a par with such well-known Russian thermal scientists as V. I. Grinevetsky and K. V. Kirsh.

In 1920, Ramzin was elected a professor at the Moscow Higher Technical School, where he headed the departments "Fuel, furnaces and boiler plants" and "Heat stations". In 1921, he became a member of the State Planning Committee of the country and was involved in work on the GOERLO plan, where his contribution was exceptionally significant. At the same time, Ramzin is an active organizer of the creation of the Thermal Engineering Institute (VTI), of which he was director from 1921 to 1930, as well as his supervisor from 1944 to 1948. In 1927, he was appointed a member of the All-Union Council of the National Economy (VSNKh), extensively dealt with issues of heat supply and electrification of the entire country, and went on important foreign business trips: to England, Belgium, Germany, Czechoslovakia, and the USA.

But the situation in the late 1920s in the country is heating up. After the death of Lenin, the struggle for power between Stalin and Trotsky sharply escalates. The warring parties deepen into the jungle of antagonistic disputes, conjuring each other with the name of Lenin. Trotsky, as People's Commissar of Defense, has an army on his side, he is supported by the trade unions, headed by their leader MP Tomsky, who opposes Stalin's plan to subordinate the trade unions to the party, defending the autonomy of the trade union movement. On the side of Trotsky, almost the entire Russian intelligentsia, which is dissatisfied with the economic failures and devastation in the country of victorious Bolshevism.

The situation favors the plans of Leon Trotsky: disagreements between Stalin, Zinoviev and Kamenev have emerged in the country's leadership, Trotsky's main enemy, Dzerzhinsky, is dying. But Trotsky at this time does not use his advantages. Opponents, taking advantage of his indecisiveness, in 1925 removed him from the post of People's Commissar of Defense, depriving him of control over the Red Army. After some time, Tomsky is released from the leadership of the trade unions.

Trotsky's attempt on November 7, 1927, on the day of the celebration of the tenth anniversary of the October Revolution, to bring his supporters to the streets of Moscow failed.

And the situation in the country continues to deteriorate. The failures and failures of the socio-economic policy in the country are forcing the party leadership of the USSR to shift the blame for the disruption in the pace of industrialization and collectivization to the "saboteurs" from among the "class enemies".

By the end of the 1920s, industrial equipment that had remained in the country since tsarist times, survived the revolution, civil war and economic ruin, was in a deplorable state. The result of this was an increasing number of accidents and disasters in the country: in the coal industry, in transport, in the municipal economy and in other areas. And since there are catastrophes, there must be culprits. A way out was found: all the troubles occurring in the country are to blame for the technical intelligentsia - wreckers-engineers. The very ones who tried their best to avoid these troubles. Engineers began to judge.

The first was the high-profile "Shakhty affair" of 1928, followed by the trials of the People's Commissariat of Railways and the gold mining industry.

It was the turn of the "case of the Industrial Party" - a major trial based on fabricated materials in the case of wrecking in industry and transport in 1925-1930, allegedly conceived and executed by an anti-Soviet underground organization known as the "Union of Engineering Organizations", "Council of the Union of Engineering Organizations ”,“ Industrial Party ”.

According to the investigation, the central committee of the "Industrial Party" included engineers: P. I. Palchinsky, who was shot by the verdict of the OGPU board in the case of sabotage in the gold-platinum industry, L. G. Rabinovich, who was convicted in the "Shakhtinsky case", and S. A. Khrennikov, who died during the investigation. After them, Professor L. K. Ramzin was declared the head of the "Industrial Party".

And in November 1930 in Moscow, in the Hall of Columns of the House of Unions, a special judicial presence of the Supreme Soviet of the USSR, chaired by the prosecutor A. Ya. Vyshinsky, begins an open hearing on the case of the counter-revolutionary organization "Union of Engineering Organizations" ("Industrial Party") and whose funding was allegedly located in Paris and consisted of former Russian capitalists: Nobel, Mantashev, Tretyakov, Ryabushinsky and others. The main prosecutor at the trial is N. V. Krylenko.

There are eight people in the dock: heads of departments of the State Planning Commission, major enterprises and educational institutions, professors of academies and institutes, including Ramzin. The prosecution claims that the Industrial Party planned a coup d'etat, that the accused even distributed positions in the future government - for example, the millionaire Pavel Ryabushinsky was planned for the post of Minister of Industry and Trade, with whom Ramzin, while on a business trip abroad in Paris, allegedly conducted secret negotiations. After the publication of the indictment, foreign newspapers reported that Ryabushinsky died back in 1924, long before possible contact with Ramzin, but such reports did not bother the investigation.

This trial differed from many others in that the public prosecutor Krylenko did not play the best role here. leading role, he could not provide any documentary evidence, since they did not exist in nature. In fact, Ramzin himself became the main accuser, who confessed to all the charges against him, and also confirmed the participation of all the accused in counter-revolutionary actions. In fact, Ramzin was the author of the accusations of his comrades.

As open archives show, Stalin closely followed the course of the trial. Here is what he writes in mid-October 1930 to the head of the OGPU V. R. Menzhinsky: “ My proposals: to make one of the most important key points in the testimony of the top of the Industrial Party and especially Ramzin the question of intervention and the timing of intervention ... it is necessary to involve other members of the Central Committee of the "Industrial Party" in the case and interrogate them rigorously about the same, allowing them to read Ramzin's testimony …».

All of Ramzin's confessions formed the basis of the indictment. At the trial, all the accused confessed to all the crimes that were brought against them, up to the connection with the French Prime Minister Poincaré. The head of the French government issued a refutation, which was even published in the Pravda newspaper and announced at the trial, but the investigation added this statement to the case as a statement by a well-known opponent of communism, proving the existence of a conspiracy. Five of the accused, including Ramzin, were sentenced to death, then commuted to ten years in the camps, the other three to eight years in the camps. All of them were sent to serve their sentences, and all of them, except for Ramzin, died in the camps. Ramzin, on the other hand, was given the opportunity to return to Moscow and, in conclusion, continue his work on the calculation and design of a high-power once-through boiler.

To implement this project in Moscow, on the basis of the Butyrskaya prison in the area of ​​\u200b\u200bthe current Avtozavodskaya Street, a “Special Design Bureau for once-through boiler building” was created (one of the first “sharashki”), where, under the leadership of Ramzin, with the involvement of free specialists from the city, design work was carried out. By the way, one of the free engineers involved in this work was the future professor of the V. V. Kuibyshev Moscow Institute of Strategic Studies M. M. Shchegolev.

And on December 22, 1933, the Ramzin direct-flow boiler, manufactured at the Nevsky Machine-Building Plant. Lenin, with a capacity of 200 tons of steam per hour, having an operating pressure of 130 atm and a temperature of 500 ° C, was put into operation in Moscow at the CHPP-VTI (now "CHP-9"). Several similar boiler houses designed by Ramzin were built in other areas. In 1936, Ramzin was completely released. He became the head of the newly created department of boiler engineering at the Moscow Power Engineering Institute, and was also appointed scientific director of VTI. The authorities awarded Ramzin the Stalin Prize of the first degree, the Orders of Lenin and the Red Banner of Labor. At that time, such awards were highly valued.

VAK USSR awarded L. K. Ramzin degree doctor of technical sciences without defending a dissertation.

However, the public did not forgive Ramzin for his behavior in court. An ice wall appeared around him, many colleagues did not shake hands with him. In 1944, on the recommendation of the Department of Science of the Central Committee of the All-Union Communist Party of Bolsheviks, he was nominated as a corresponding member of the USSR Academy of Sciences. In a secret ballot at the Academy, he received 24 votes "against" and only one "for". Ramzin was completely broken, morally destroyed, his life was over. He died in 1948.

Comparing the scientific developments and biographies of these two scientists, who worked almost at the same time, we can assume that i-d- diagram for calculating the parameters of humid air, most likely, was born on German soil. It is surprising that Professor Ramzin began to claim authorship i-d- diagrams only four years after the appearance of the article by Richard Mollier, although he always closely followed the new technical literature, including foreign ones. In May 1923, at a meeting of the Thermal Engineering Section of the Polytechnic Society at the All-Union Association of Engineers, he even made a scientific report on his trip to Germany. Being aware of the work of German scientists, Ramzin probably wanted to use them in his homeland. It is possible that he had attempts in parallel to conduct similar scientific and practical work at Moscow Higher Technical School in this area. But not a single application article on i-d-diagram has not yet been found in the archives. Drafts of his lectures on thermal power stations, on testing various fuel materials, on the economics of condensing units, etc., have been preserved. And not a single, even a rough entry on i-d-diagram, written by him before 1927, has not yet been found. So we have, despite patriotic feelings, to conclude that the author i-d-chart is precisely Richard Mollier.

1. Nesterenko AV, Fundamentals of thermodynamic calculations of ventilation and air conditioning. - M.: Higher school, 1962.
2. Mikhailovsky G.A. Thermodynamic calculations of the processes of steam-gas mixtures. - M.-L.: Mashgiz, 1962.
3. Voronin G.I., Verbe M.I. Air conditioning in aircraft. - M.: Mashgiz, 1965.
4. Prokhorov V.I. Air conditioning systems with air chillers. - M.: Stroyizdat, 1980.
5. Mollier R. Einneues. Diagramm für Dampf-Luftgemische. Zeitschrift des Vereins Deutscher Ingenieure. 1923. No. 36.
6. Ramzin L.K. Calculation of dryers in the i-d-diagram. - M.: Proceedings of the Thermal Engineering Institute, No. 1 (24). 1927.
7. Gusev A.Yu., Elkhovsky A.E., Kuzmin M.S., Pavlov N.N. The riddle of the i-d-diagram // ABOK, 2012. No. 6.
8. Lurie M.Yu. A method for constructing an i-d-diagram by Professor L. K. Ramzin and auxiliary tables for humid air. - M .: News of the Thermal Engineering Institute, 1927. No. 1 (24).
9. A blow to the counter-revolution. The indictment in the case of the counter-revolutionary organization of the Union of Engineering Organizations ("Industrial Party"). - M.-L., 1930.
10. Process of the "Industrial Party" (from 11/25/1930 to 12/07/1930). Transcript of the trial and materials attached to the case. - M., 1931.

For many mushroom pickers, the expressions “dew point” and “catch condensate on primordia” are familiar.

Let's look at the nature of this phenomenon and how to avoid it.

From school course everyone knows from physics and from their own experience that when it gets quite cold outside, fog and dew may form. And when it comes to condensate, most imagine this phenomenon as follows: once the dew point has been reached, then water from the condensate will flow from the primordia in streams or drops will be visible on the growing mushrooms (the word “dew” is associated with drops). However, in most cases, the condensate forms in the form of a thin, almost invisible water film, which evaporates very quickly and is not even felt to the touch. Therefore, many are perplexed: what is the danger of this phenomenon, if it is not even visible?

There are two such dangers:

1. since it occurs almost imperceptibly to the eye, it is impossible to estimate how many times a day the growing primordia were covered with such a film, and what damage it caused them.

It is precisely because of this "invisibility" that many mushroom pickers do not attach importance to the very phenomenon of condensate precipitation, they do not understand the importance of its consequences for the formation of the quality of mushrooms and their yield.

1. The water film, which completely covers the surface of primordia and young mushrooms, does not allow moisture to evaporate, which accumulates in the cells of the surface layer of the mushroom cap. Condensation occurs due to temperature fluctuations in the growth chamber (details below). When the temperature equalizes, a thin layer of condensate evaporates from the surface of the cap, and only then does moisture begin to evaporate from the body of the oyster mushroom itself. If the water in the cells of the mushroom cap stagnates long enough, then the cells begin to die. Long-term (or short-term, but periodic) exposure to a water film inhibits the evaporation of the fungal bodies' own moisture to such an extent that primordia and young mushrooms up to 1 cm in diameter die.

When primordia turn yellow, soft like cotton wool, flow from them when pressed, mushroom pickers usually attribute everything to “bacteriosis” or “bad mycelium”. But, as a rule, such death is associated with the development of secondary infections (bacterial or fungal), which develop on primordia and fungi that died from the effects of condensate exposure.

Where does condensation come from, and what should be the temperature fluctuations in order for the dew point to occur?

For an answer, let's turn to the Mollier diagram. It was invented to solve problems in a graphical way, instead of cumbersome formulas.

We will consider the simplest situation.

Imagine that the humidity in the chamber remains unchanged, but for some reason the temperature begins to drop (for example, water enters the heat exchanger at a temperature below normal).

Suppose the air temperature in the chamber is 15 degrees and the humidity is 89%. On the Mollier diagram, this is the blue point A, to which the orange straight line led from the number 15. If we continue this straight line upwards, we will see that the moisture content in this case will be 9.5 grams of water vapor per 1 m³ of air.

Because we assumed that the humidity does not change, i.e. the amount of water in the air has not changed, then when the temperature drops by only 1 degree, the humidity will be already 95%, at 13.5 - 98%.

If we lower the straight line (red) from point A down, then at the intersection with the 100% humidity curve (this is the dew point), we will get point B. Drawing a horizontal straight line to the temperature axis, we will see that the condensate will begin to fall at a temperature of 13.2.

What does this example give us?

We see that a decrease in temperature in the zone of formation of young drusen by only 1.8 degrees can cause the phenomenon of moisture condensation. Dew will fall exactly on the primordia, as they always have a temperature 1 degree lower than in the chamber - due to the constant evaporation of their own moisture from the surface of the hat.

Of course, in a real situation, if air comes out of the duct two degrees lower, then it mixes with warmer air in the chamber and the humidity rises not to 100%, but in the range from 95 to 98%.

But, it should be noted that in addition to temperature fluctuations in a real growing chamber, we also have humidification nozzles that supply moisture in excess, and therefore the moisture content also changes.

As a result, cold air can be supersaturated with water vapor, and when mixed at the outlet of the duct, it will end up in the area of ​​fogging. Since there is no ideal distribution of air flows, any displacement of the flow can lead to the fact that it is near the growing primordium that the dew zone is formed that will destroy it. At the same time, primordia growing nearby may not fall under the influence of this zone, and condensation will not fall on it.

The saddest thing in this situation is that, as a rule, the sensors hang only in the chamber itself, and not in the air ducts. Therefore, most mushroom growers do not even suspect that such fluctuations in microclimatic parameters exist in their chamber. Cold air leaving the air duct mixes with a large volume of air in the room, and air with “averaged values” for the chamber comes to the sensor, and a comfortable microclimate is important for mushrooms in the zone of their growth!

The situation with condensation becomes even more unpredictable when the humidification nozzles are not located in the air ducts themselves, but are hung around the chamber. Then the incoming air can dry the mushrooms, and the nozzles that suddenly turn on can form a continuous water film on the hat.

From all this, important conclusions follow:

1. Even slight temperature fluctuations of 1.5-2 degrees can cause condensation and the death of fungi.

2. If you cannot avoid fluctuations in the microclimate, then you will have to lower the humidity to the lowest of possible values(at a temperature of +15 degrees, the humidity should be at least 80-83%), then it is less likely that the air will be completely saturated with moisture when the temperature drops.

3. If most of the primordia in the chamber have already passed the phlox* stage and are larger than 1-1.5 cm, then the risk of death of fungi from condensate decreases due to the growth of the cap and, accordingly, the evaporation surface area.
Then the humidity can be raised to the optimum (87-89%), so that the mushroom is denser and heavier.

But do it gradually, no more than 2% per day - as a result of a sharp increase in humidity, you can again get the phenomenon of moisture condensation on mushrooms.

* The phlox stage (see photo) is the stage of development of primoriums, when there is a division into individual mushrooms, but the primordia itself still resembles a ball. Outwardly, it looks like a flower with the same name.

4. It is obligatory to have humidity and temperature sensors not only in the room of the oyster mushroom growing chamber, but also in the growth zone of primordia and in the air ducts themselves, to record temperature and humidity fluctuations.

5. Any air humidification (as well as its heating and cooling) in the chamber itself unacceptable!

6. The presence of automation helps to avoid fluctuations in temperature and humidity, as well as the death of mushrooms for this reason. A program that controls and coordinates the influence of microclimate parameters must be written specifically for oyster mushroom growth chambers.

After reading this article, I recommend reading the article about enthalpy, latent cooling capacity and determination of the amount of condensate formed in air conditioning and dehumidification systems:

Good day, dear beginner colleagues!

At the very beginning of my professional journey, I came across this diagram. At first glance, it may seem scary, but if you understand the main principles by which it works, then you can fall in love with it: D. In everyday life, it is called i-d diagram.

In this article, I will try to simply (on my fingers) explain the main points, so that later, starting from the received foundation, you will independently delve into this web of air characteristics.

This is what it looks like in textbooks. It gets kind of creepy.

I will remove all that is superfluous that I will not need for my explanation and present the i-d diagram in this form:

(to enlarge the image, click and then click again)

It's still not entirely clear what it is. Let's break it down into 4 elements:

The first element is moisture content (D or d). But before I start talking about air humidity in general, I would like to agree on something with you.

Let's agree "on the shore" at once about one concept. Let's get rid of one firmly entrenched in us (at least in me) stereotype about what steam is. From the very childhood, they pointed me at a boiling pot or teapot and said, poking a finger at the “smoke” coming out of the vessel: “Look! That's steam." But like many people who are friends with physics, we must understand that “Water vapor is a gaseous state water. Doesn't have colors, taste and smell. It's just H2O molecules in the gaseous state, which are not visible. And what we see, pouring out of the kettle, is a mixture of water in a gaseous state (steam) and “water droplets in the boundary state between liquid and gas”, or rather, we see the latter (with reservations, we can also call what we see - mist). As a result, we get that in this moment, around each of us is dry air (a mixture of oxygen, nitrogen ...) and steam (H2O).

So, the moisture content tells us how much of this vapor is present in the air. On most i-d diagrams, this value is measured in [g / kg], i.e. how many grams of steam (H2O in gaseous state) is in one kilogram of air (1 cubic meter of air in your apartment weighs about 1.2 kilograms). In your apartment for comfortable conditions in 1 kilogram of air there should be 7-8 grams of steam.

On i-d chart the moisture content is shown as vertical lines, and the gradation information is located at the bottom of the diagram:

(to enlarge the image, click and then click again)

The second important element to understand is air temperature (T or t). I don't think there is any need to explain here. On most i-d diagrams, this value is measured in degrees Celsius [°C]. On the i-d diagram, the temperature is depicted by slanted lines, and the gradation information is located on the left side of the diagram:

(to enlarge the image, click and then click again)

The third element of the ID diagram is relative humidity (φ). Relative humidity is exactly the kind of humidity we hear about on TVs and radios when we listen to the weather forecast. It is measured as a percentage [%].

A reasonable question arises: “What is the difference between relative humidity and moisture content?” I will answer this question step by step:

First stage:

Air can hold a certain amount of vapor. Air has a certain “steam load capacity”. For example, in your room, a kilogram of air can “take on board” no more than 15 grams of steam.

Suppose your room is comfortable, and in every kilogram of air in your room there is 8 grams of steam, and each kilogram of air can contain 15 grams of steam. As a result, we get that 53.3% of the maximum possible steam is in the air, i.e. relative humidity - 53.3%.

Second phase:

The air capacity is different at different temperatures. The higher the air temperature, the more steam it can contain, the lower the temperature, the lower the capacity.

Suppose that we have heated the air in your room with a conventional heater from +20 degrees to +30 degrees, but the amount of steam in each kilogram of air remains the same - 8 grams. At +30 degrees, the air can “take on board” up to 27 grams of steam, as a result, in our heated air - 29.6% of the maximum possible steam, i.e. relative humidity - 29.6%.

The same goes for cooling. If we cool the air to +11 degrees, then we get a “carrying capacity” equal to 8.2 grams of steam per kilogram of air and a relative humidity of 97.6%.

Note that there was the same amount of moisture in the air - 8 grams, and the relative humidity jumped from 29.6% to 97.6%. This happened due to temperature fluctuations.

When you hear about the weather on the radio in winter, where they say that it is minus 20 degrees outside and the humidity is 80%, this means that there are about 0.3 grams of vapor in the air. When you get into your apartment, this air heats up to +20 and the relative humidity of such air becomes 2%, and this is very dry air (in fact, in the apartment in winter, the humidity is kept at 10-30% due to the release of moisture from the bathrooms, from kitchens and from people, but which is also below the comfort parameters).

Third stage:

What happens if we lower the temperature to such a level that the “carrying capacity” of the air is lower than the amount of vapor in the air? For example, up to +5 degrees, where the air capacity is 5.5 grams / kilogram. That part of the gaseous H2O that does not fit into the “body” (in our case it is 2.5 grams) will begin to turn into a liquid, i.e. in water. In everyday life, this process is especially clearly visible when the windows fog up due to the fact that the temperature of the glasses is lower than the average temperature in the room, so much so that there is little room for moisture in the air and the vapor, turning into a liquid, settles on the glasses.

On the i-d diagram, relative humidity is shown as curved lines, and the gradation information is located on the lines themselves:

(to enlarge the image, click and then click again)

The fourth element of the ID diagram is the enthalpy (I or i). Enthalpy contains the energy component of the heat and moisture state of air. Upon further study (outside of this article, for example in my article on enthalpy ) it is worth paying special attention to it when it comes to dehumidification and humidification of the air. But for now, we will not focus on this element. Enthalpy is measured in [kJ/kg]. On the i-d diagram, the enthalpy is depicted by slanted lines, and the information about the gradation is located on the graph itself (or on the left and in the upper part of the diagram).

I-d humid air diagram - a diagram widely used in the calculations of ventilation, air conditioning, drying and other processes associated with a change in the state of humid air. It was first compiled in 1918 by the Soviet heating engineer Leonid Konstantinovich Ramzin.

Various I-d diagrams

I-d diagram of moist air (Ramzin diagram):

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Diagram Description

I-d-diagram of moist air graphically connects all the parameters that determine the heat and moisture state of air: enthalpy, moisture content, temperature, relative humidity, partial pressure of water vapor. The diagram is built in an oblique coordinate system, which allows expanding the area of ​​unsaturated moist air and makes the diagram convenient for graphic constructions. The ordinate axis of the diagram shows the values ​​of enthalpy I, kJ/kg of the dry part of the air; the abscissa axis, directed at an angle of 135° to the I axis, shows the values ​​of the moisture content d, g/kg of the dry part of the air.

The diagram field is divided by lines of constant values ​​of enthalpy I = const and moisture content d = const. It also has lines of constant temperature values ​​t = const, which are not parallel to each other - the higher the temperature of moist air, the more its isotherms deviate upward. In addition to lines of constant values ​​of I, d, t, lines of constant values ​​of relative air humidity φ = const are plotted on the diagram field. In the lower part of the I-d-diagram there is a curve with an independent y-axis. It links moisture content d, g/kg, with water vapor pressure pp, kPa. The y-axis of this graph is the scale of the partial pressure of water vapor pp.