How does a snow gun work. Ice sculptures, Ice figures, Ice towns in winter

06.03.2017 08:38

Today, snow guns are an indispensable thing in various fields. This is a snow making device with a powerful fan. Snow cannons are used in auto and aircraft construction, in the national economy. But they are especially popular in the field of sports recreation, in ski resorts. With the help of this miracle device, it is possible not only to create artificial snow, but also to spray it in the right direction at any distance.

Why and in what cases do the organizers of sports competitions and outdoor activities resort to the creation of artificial snow cover? The first reason is that there is not enough snow on the ski slopes or in areas where there are camp sites for active winter recreation. Also it is impossible not to note the quality of the resulting snow. If real snow consists of snowflakes, then artificial snow is completely made of frozen drops of water. This increases the humidity and density of the resulting snow cover, it remains even in all areas. Thus, it becomes possible to create the same conditions for all participants in sports events (which take place in an area with artificial snow cover).

Also, artificial snow does not melt longer than usual. What is it connected with? The answer again comes down to the composition of the snow. The particles of the resulting snow in their appearance are more like small grains, they do not crystallize to real snowflakes. In addition, snow from cannons is cleaner and more uniform, it does not contain foreign impurities, dust and other substances that contribute to rapid melting.

Snow production: myth or reality?

Nowadays, snow production is not a myth, but a reality. You can get snow of the desired quality with the help of a miracle of technology - snow guns. So, the first function of a snow gun is to make snow. How does it work? What determines the quality and physical properties of the produced snow flakes?

Artificial snow can be obtained in different ways - it all depends on the temperature of the water and air, as well as the duration of the flight from the atomizer. Snow flakes are mixed with air and then released into the atmosphere. Snow is softer in consistency if it is in a state of flight longer. If snow fell to the ground very quickly, it would be heavy and wet. We can say that the whole thing is in the device of the gun. Due to the fact that its fan is powerful and can spray water over very long distances, soft snow is obtained.

There are more and more people skiing and snowboarding, and there are fewer and fewer places suitable for skiing.

Global warming has reduced the season at some of the oldest ski resorts from four months to one or two. There are forecasts according to which the center of the European ski industry will soon shift from the Alps to Scandinavia. In search of snow, Americans have already begun to explore Alaska. Everything, there is nowhere else to go. It remains only to use weapons. Special. If you didn’t go beyond the Arctic Circle for snow, then most likely, at your favorite resort you ride on ersatz - artificial, or technical, as professionals call it, snow. Today, not a single resort can do without special snow-making machines, from French Chamonix to Volen near Moscow. Almost every rider has seen snow guns in action and their lighter versions - snow guns. From the outside, the process of snow formation looks simple: giant fans spray water, which turns into snow in the cold. But this is only from the side.

real snow

Natural snow is formed from atmospheric water vapor. When water vapor, which is the gaseous form of water, cools to the point of condensation, it changes from gaseous to liquid or solid form. Clouds familiar to us consist of just such condensed drops, though so small that they are easily kept at the top by rising air flows. When the droplets become too heavy, they fall to the ground as rain. If the temperature is much below the dew point, water vapor bypasses the liquid phase, forming small crystals. In most parts of the globe, the usual rain for us begins, oddly enough, with a snowfall, but the snowflakes have time to melt as they approach the ground. The fact is that at the height of the formation of clouds there is always a negative temperature, comparable to the Yakut frosts. A simple confirmation of this fact is hail in a hot summer.

However, water does not automatically freeze when the temperature falls below freezing. Distilled water can be cooled down to a fairly low temperature of -40°C and still remain a liquid. However, in real life, the vapor in the clouds begins to crystallize already at 0 °C. The fact is that in order for the process of condensation to start, water needs the smallest particles around which its molecules could settle. Such centers of condensation in the atmosphere are the smallest particles of soot, urban smog, bacteria and other materials. For example, this is how clouds are dispersed by spraying special reagents (for example, silver iodide) from airplanes above them, which act as just such centers of condensation.

Crystallizing, the water in the clouds forms bizarre six-beam fractal shapes called snowflakes. The longer the crystallization process takes, the more complex the pattern of the snowflake. In the clouds, this process takes tens of minutes. Artificial snow, on the other hand, forms in seconds, so upon closer inspection, its crystals look like hexagonal ones with ray nuclei, and feel like grains to the touch. However, such snow melts more slowly than natural snow, and skis on it glide differently.

snow guns

The idea used to disperse clouds (condensation of water around artificial condensation centers) is also perfectly suited for the production of artificial snow. One of the most common crystallizers used in snowmaking is Snowmax, a special natural protein that does an excellent job of attracting water molecules.

In the early designs of snow guns, water was mixed with compressed air and expelled through nozzles at high pressure into a stream of air generated by a powerful fan. Compressed air performed three tasks at once: it sprayed water, threw the resulting droplets into the air, and additionally cooled the water. The latter effect is based on the fact that gases cool during adiabatic expansion. Try to open a can of carbon dioxide - it will instantly cool to sub-zero temperatures, risking frostbite on your hands.

The disadvantage of this scheme is the high air consumption. Therefore, more modern guns operate in a two-stage process. First, by mixing compressed air and a small amount of water, tiny ice crystals are formed - the embryos of artificial snow. Then these "embryos" fall into the stream of water sprayed by powerful fans, which, crystallizing on them, quickly forms ready-made snow crystals.

A distinctive feature of all guns is a powerful fan that ejects a water-air mixture over tens of meters. During such a flight, crystals of artificial snow have time to form, in addition, the high “range” allows you to snow large areas. In ski resorts, you can also see another type of snow gun - snow guns. Their difference from guns is in the absence of a fan.

The process of snow formation in them is as follows. The spaced apart air and first water nozzles supply a limited amount of water and air to the mixing zone, located at a distance of 810 cm from the gun, where the snow crystals are nucleated. These mini-crystals are displaced by inertia further, at a distance of approximately 20 cm from the gun, they enter the water stream from the second nozzle, where water sticks to them. Snow crystallization occurs during the free fall of crystals to the ground from a height of at least 4 m.

Snow conditions

The presence of snow artillery does not yet mean the solution of snow problems. Much also depends on the conditions of snow formation, the most important parameters of which are temperature and relative humidity (the ratio of water vapor actually contained in the air to the amount of water vapor corresponding to the state of saturation). The fact is that water is cooled by its own partial evaporation, that is, the transition of part of the liquid into vapor. However, the higher the relative humidity, the slower will be the evaporation process and, consequently, the cooling.

Therefore, at low relative humidity, snow formation is possible at temperatures above 00C. At high humidity and at low temperatures, it is possible to get ordinary rain instead of snow. With a relative humidity of 30%, it is possible to run snow guns at -1°C, which is considered good conditions for snow formation. If the temperature falls below -6.7°C, then it is possible to make snow even at 100% relative humidity. At temperatures below -10°C, humidity can be ignored.

It is not surprising, therefore, that there are people who are willing to pay for what usually falls from the sky "for free". As, accordingly, there are those who produce this artificial snow. Many ski resorts, including those in Russia and Sweden, thanks to the use of special "snow-making" systems, extend the ski season by as much as four months (two in the beginning of winter and two in the spring). In addition, it should be noted that at this time the weather is the most mild and favorable, that is, ideal for a wonderful family vacation ...

HUNDRED NAMES FOR SNOW

It is said that in the languages ​​of Northern Scandinavia there are a hundred words for snow, which is not at all surprising. For there is plenty of this "goodness" here in winter, and the structure of snow itself is very changeable and dependent on temperature and humidity. Ski lovers are well aware that snow can be "hard", "soft", wet, etc. Sometimes the skis run "by themselves", and literally the next day you need to make an effort even to move downhill.

In modern ski competitions, tenths of a second sometimes decide the fate of medals. And in alpine skiing, the score is already in the hundredths and thousandths! And now, after we have been looking forward to international competitions for a year or even two, we buy tickets ahead of time and book a hotel, the organizers suddenly cancel everything at the last moment. Since Heaven didn't "send" the much-needed snow to the right place, which instead fell all over again near your garage...

According to data from the Swedish Regional Climate Modeling Project (SWECLIM), by 2010 the average annual temperature in Sweden will increase by 3.8oC. It is estimated that warming in Northern Europe will be more significant than in other regions, which can bring big disappointments to winter sports fans. The expected increase in the annual precipitation rate is also expected to occur, most likely, due to summer and especially autumn rains. Together with an increase in average winter temperatures, this will lead to a decrease in snow cover and a later opening of the ski season. Moreover, problems with snow are typical not only for Scandinavia. For example, in the ski resorts of Eastern Siberia, the opening of the ski season in 2003 took place only on New Year's Eve, and in the winter of 1998-99 - only on January 3!

Thus, "artificial" snow in skiing represents stability and quality. Snow systems are used when control over the situation is needed: to ensure that the snow lies where it is needed, when it is needed, and the way it is needed. It should be noted that the use of snow systems goes beyond sports. "Artificial" snow can be used to test aircraft anti-icing systems, to test winter tires, and even to protect young forest plantations from frost.

IS IT EASY TO MAKE SNOW?

Most are sure that "making" snow is as easy as shelling pears - there would be water and frost. But this is only apparent simplicity. We offer those who live in cold climates a simple and safe experiment. Take a water spray that is commonly used to dampen houseplants or when ironing clothes. Fill it with cold water from the faucet, go outside on a cold (colder than -10°C) day, and start spraying the water higher into the air. What do you think you will be able to do? Big and fluffy snowflakes? Nothing of the kind - small shiny ... ice floes.

Why do snowflakes fall from the sky in winter? The "secret of their production", hidden high in the clouds, lies in the gradual growth of ice microcrystals on the so-called initial "condensation center" under certain conditions. If the conditions are unsuitable, instead of snowflakes, solid ice balls (summer hail) or what is called "groats" in Russia, that is, relatively dense, granular snow, characteristic of late autumn, will fall.

What is necessary for successful "snowmaking"? Obviously, water of a certain temperature, "splashed" in a certain way, cold air ... Also - some kind of natural "magic" or, at least, sophisticated technical equipment. And only then will we be able to announce with all confidence: let there be Snow! And he will!

LET'S LOOK INTO THE SNOW GUN

And now - for those inquisitive who are not afraid of some technical details. Snow machines in use today can be divided into two main types: fan (commonly called "snow guns") and mast. In Russia, generators of the first type are most common. The main unit of these devices, as the name suggests, is a high power fan that creates a continuous stream of air into which water droplets are then injected.

The mixture ejected by the generator must spend some time in the air before falling to the ground as well-formed snow. Therefore, it is difficult for a "snow gun" to throw snow "right under its feet", since the best snow is obtained at a distance of about 10-20 m from the installation. This is easier to do with special snow masts, which are also cheaper than fan guns.

All modern snow generators are equipped with automation systems of varying complexity (from overload protection systems to full control systems).

MAKING SNOW IS ART!

The modern snowmaking system is not limited to snow generators placed along the ski slope or track. Obviously, it is still necessary to lay pipes for supplying water and an electric cable. At the same time, pipes should not freeze even in the most severe frost, therefore they are usually dug into the ground (in Siberia and Central Sweden - to a depth of at least 50-70 cm). At certain intervals, you need to organize "connection points" of snow guns, including an electrical connector and water supply devices ("hydrant").

Do not forget that even a "simple" ski slope can be more than a kilometer long and have a height difference of 400-500 m. On such a slope, you will need to place about ten "connection points", and at the foot - a high-pressure water pump (up to 40 atmospheres) high performance. To throw a sufficient amount (usually 10-20 cm) of "artificial" snow on a kilometer-long slope, 4-5 "snow guns", each of which consumes up to 500 liters of water per minute (corresponding to about one average bath of water in 15 seconds), should work continuously for 5-7 days. In general, the performance of modern snow guns is amazing - they are capable of producing up to 100 m3 of snow per hour! "Snow guns" with a hydraulic rotary device are capable of covering up to 1000 m2 of surface with snow each.

Snowmaking a cross-country track is by no means easier. Here, of course, there are no such elevation changes as on the ski slopes or ski jumps, but the length of the tracks is already tens of kilometers long. Laying such long pipelines is quite expensive. That is why one of the common solutions is to install "snow guns" and water tanks on a self-propelled chassis, wheeled or tracked. In this case, snowmaking of any area is only a matter of time.

How to check how good freshly made snow is? Arrange a product "quality" check? Experts say that snow for a ski slope should have a density of 400 to 500 kg per m3, that is, be 2-2.5 times lighter than ice or water.

Density measurement is reduced to measuring the weight of a piece of "snow cake" of a certain size, carefully cut from the slope. There is, however, an easier way. Astute skiers may have noticed that snowmen (the main "snowmakers") are usually dressed in black jackets made of a special material. This is not just a uniform, but a kind of "tool" for checking the quality of snow. To do this, the "snowmaker" approaches the working "cannon" and puts his hand under the snow stream at a distance of about 15 m from the exit cut. After 15-20 seconds (the exact figures are a trade secret!) the specialist steps aside and shakes the snow off his sleeve, dangling his hand. Then he checks what is stuck on the fabric. If all the snow has been shaken off, it is too dry. If it's all left, it's too wet. The desired quality lies somewhere in the middle. And just here the art of "snowmaking" begins.

RECIPE FOR GOOD SNOW

Modern snow guns have a sufficient number of "degrees of freedom" to adjust and ensure good snow quality at any sufficiently low air temperature. But what if the external conditions (air temperature, humidity) change rapidly? It is clear that in this case it is necessary to constantly adjust the "tuning" of the generator so that the quality of the snow produced does not decrease. Fortunately, with automation, the operator does not have to run up and down the slope to reset the system. Moreover, automatic adjustment can be carried out both at the level of an individual snow gun, and at the level of the entire snowmaking system as a whole. Complex automation systems, which include microprocessors and stationary computers, as well as "weather stations" can work without much human intervention for weeks and months.

To use a restaurant analogy, the recipe for good "snowmaking" using an automated system is more like an instruction manual for some modern bread machine: "put flour, yeast, pour water, press the button and wait for the call - it's done!" Of course, no self-respecting chef will allow himself anything like this: everything will be done traditionally, in "manual mode", adjusted for "scent and sight". Likewise, a good "snowmaker", who has many years of work behind him, will regulate the system taking into account many factors known only to him: was there a "halo" around the sun today, how did the snow crunch yesterday, what color was the sunset, and God knows what more... However, both a good cook and a skilled "snowmaker" are not easy to find, and they have to pay astronomical sums. Computer automation is cheaper, easier to manage, and does not argue if you have to work overtime.

By the way, at international competitions, where the "cream" of the sports beau monde hang out, the snow is prepared by just not unique specialists. Modern sporting events require, where possible, standard equipment and standard conditions of conduct in order to ensure equality for all participants. Therefore, more and more competition organizers are turning to automated snowmaking systems even with a sufficient amount of natural snow, which is very difficult to standardize.

In northern Europe for the period 1990-2100. Significant climate changes are expected due to an increase in average winter temperatures (A) and annual precipitation (B).

Production of "artificial" snow for more than 50 years. The first experimental installations began to be created in the 1950s and 60s. in countries where skiing was very popular. Patents for artificial snow were filed in 1968.

In fan snow "cannons" a powerful fan (4) creates a continuous flow of air that moves through the main (1) and nucleation (2) rings with nozzles. Water is supplied under pressure to the first rings, and a water-air mixture is supplied to the second.

Through the nozzles of the main rings, tiny water droplets are injected into the air stream. The nozzles of the "nucleation" ring create the condensation centers necessary for the formation and growth of snow.

Between the fan and the rings there are blade-plates (3) attached from the inside to the generator casing. They contribute to better mixing of the components of the water-air mixture.

Many snow guns use multiple main rings, each with a separate water valve. Thanks to this, the performance of the snow gun can be controlled. The main components are enclosed in a metal casing (6) with a protective mesh (5) at the system inlet.

The snow machine also has devices for supplying electricity (7), high pressure water (9) and compressed air (8).

Fan snow guns can also be mounted on a self-propelled tracked chassis
In snow cannons, the snow gun housing (D), automation system (A) and compressor (C) are mounted either on a wheeled chassis or on a solid "leg" (T). Water is supplied through a hose with a special connector for quick connection (W). Control signals (CS) are given from the central computer system via a separate "signal cable" or by radio

At the snow "mast", the snow-generating elements are raised above the ground to a height of up to 10 m. Thanks to this, all the sprayed water has time to completely condense in the form of snow, while the latter falls to the ground under its own weight.

The work of preparing a snow slope or track is not limited to the production of snow. After generation, the snow should "lay down" for several days ("ripen", as young wine ripens). After that, it is the turn of special snow machines (the so-called pistmachines or retraks), which level the snow, compact and soften its surface.

In conclusion, we want to wish the readers good snow - for the current and all future ski seasons! We also want to wish those who have not yet joined the ski "fun" to try at least once. After all, today's opportunities for ski enthusiasts of all ages and any qualifications are simply inexhaustible!

Aside from the obvious health benefits of spending time outdoors while combating the effects of physical inactivity, skiing is a lot of fun! Well, when you find yourself back on your favorite slope, you can competently tell your friends about how much effort and knowledge is hidden behind seemingly so simple and familiar "perfect" snow.

The authors:
KOPTYUG Andrey Valentinovich - Candidate of Physical and Mathematical Sciences, graduate of Novosibirsk State University. Associate Professor at the Faculty of Information Technology at the University of Central Sweden (Östersund)
ANANEV Leonid Grigorievich - director of the Swedish-Russian company SveRuss Konsul (SveRuss Konsul) (Sweden, Östersund)
OSTREM Johan - MSc in Engineering, director of AREKO Snowsystem (ARECO Snowsystem) (Sweden, Östersund)

The article is printed in abbreviated form.

Evgeny Tsiporin / Alexander Kozlov / Alexander Butenko

(Gorimpeks group of companies)

Russia is a country with the largest (in the future) ski equipment market, as well as with the world's largest opportunities for the construction and operation of modern ski centers. Today, the vast majority of Russian skiers do not ski in the best conditions, which means that there is a shortage, which means that the market for the construction of this kind of sports facilities is super promising, ski centers will be in demand for sure. However, this market has a number of features. It is worth noting that most of the Russian ski centers that exist in reality or on paper are located close to large cities, which is like a set of “pluses” (it is convenient to get from the city limits to the ski slope, it is convenient to organize the work of the ski center itself in terms of communications, etc.). etc.), and a set of "minuses" and about one of these "minuses" it is necessary to say in detail.

The fact is that the majority of Russian cities, and especially the “million-plus” cities around which ski centers are gathered, are located in an area with unstable winters, with changeable weather from November to March and with priceless snow cover instantly disappearing in case of a thaw. Everyone remembers the "monstrous" winter of the 2006-2007 season, which beat all indicators in terms of high temperatures - up to +14 ° C in Moscow in January, and such "records" were set throughout the European territory of Russia.

Naturally, such natural disasters “kill” any demand for the services of ski centers, nullify all efforts for construction and improvement: there is no snow - none of the skiers will come to look at the green grass that has melted through the frozen mud. At the same time, even such “minuses” can be turned into “pluses” using modern technologies, namely, by installing mechanical snowmaking systems at ski centers, simply speaking, systems that make artificial snow.

Such technologies have been used in the West for many years, they are carefully developed and allow even in the conditions of the city (for example, the annual stage of the World Cup in cross-country skiing in Dusseldorf) to make a full-fledged ski track.

However, these technologies have a number of features that must be taken into account.

Almost all ski centers in Europe use snow production with snowmaking systems during periods when there is not enough natural snow for full skiing. The process of artificial snow formation requires three components - low ambient temperature, a significant amount of water and, finally, the presence of compressed air. When obtaining snow with the help of snow generators (snow guns), significant volumes of water and electrical power are used. This article includes the following sections:

1. Snowmaking systems

2. Reservoirs

3. Wet/Dry Bulb Temperature

4. Special additives

5. Water pre-cooling systems

6. Management of snowmaking systems

7. Air compressors

8. Pipelines

1. Snowmaking systems

A professional approach to making quality snow is very important and many of the snowmaking system suppliers say "Snow making is an art". Snow quality from snowmaking systems can range from "very dry" to "very wet". Trails for beginners, for mass use, are not the same as trails for professionals, and require a completely different thickness of snow cover and snow quality. The quality of the snow also affects the convenience of the process of distributing it along the ski slopes. For example, to obtain a track of exceptional quality, it is often necessary to lay a layer of dry and light snow on top of the main layer of wet heavy snow.

Snowmaking systems reproduce the natural process of snow formation. In nature, snow forms as a result of the condensation of water vapor into ice microcrystals at low ambient temperatures and low relative humidity. Pure water freezes (theoretically) at temperatures below 0°C when several water molecules join together to form what is called an embryo, seed, or nucleation center. Nearby water molecules continue to attach to the embryo and form ice crystals. This process is called homogeneous nucleation. If impurities are present in the formation of ice crystals in water, then this process is called heterogeneous nucleation. Impurities serve as nucleation centers (seeds) for the formation of ice crystals. Heterogeneous nucleation is possible even at positive ambient temperatures. The temperature at which ice crystals form on impurities is called the heterogeneous nucleation temperature. Snowmaking machines, or snowmakers, use these physical processes to make snow using cooling compressed air, water, and sometimes additives that are used as crystallization catalysts.

There are three types of snow guns (snow guns) - internal mixing snow guns, external mixing snow guns, and finally fan snow guns. Factors that are considered when choosing the type of equipment include:

Wind speed;

Direction of the wind;

Ambient temperature;

relative humidity;

Availability of compressed air;

Availability of electricity;

The location of the slopes to the cardinal points;

The following are brief descriptions of the three types of snowmaking systems:

Internal mixing system - a system using the mixing of water and air in the internal chamber of the snow gun nozzle. When the mixture of water and compressed air leaves the nozzle, this mixture expands and the thermodynamic effect of cooling (below 0 °C) occurs. Tiny water droplets freeze to form microcrystals, which in turn become nucleation centers. On such nucleation centers (seeds) snow flakes are formed from larger droplets.

External Mix System - Another type of water-air system. Such systems provide for the exit of compressed air and pressurized water through separate nozzles of the snow gun. The compressed air expands and greatly cools the microscopic water droplets coming out of the water nozzles. In this case, nucleation centers are formed. In systems with external mixing, the jet velocity is lower than in systems with internal mixing. For this reason, external mixing snow guns are mounted on towers to give water droplets enough time to nucleate and form snow before they reach ground level. Sometimes systems with external mixing are used without the use of compressed air and fans. At the same time, expensive additives, high pressures and chilled water are used to successfully produce high-quality snow.

Fan systems - Fan systems use fan driven air instead of compressed air to suspend water droplets in the air. In this case, the droplets are in the air for a sufficient time to significantly cool and freeze. Fan systems are often also equipped with devices for nucleation. Typically, such a device consists of a small air compressor mounted directly on the snow machine and a circuit of nucleating air nozzles. In this case, the mixing of compressed air with water and subsequent crystallization takes place already in the environment. This type of guns is the most popular and widespread.

Snow guns that are used in both internal and external mixing systems do not require an external power source at the snow gun installation site. But, despite this advantage, such systems require centralized compressor and pumping stations. Fan guns require the supply of power cables directly to the installation site of the snow guns to power the fans and air compressors. Internal mixing and fan gun systems operate over a very wide temperature range and control snow quality through the use of fans and air compressors. These technologies are best suited for wide trails and trails that are scheduled to open at the very beginning of the winter season for initial snow coverage. External mixing systems are more economical in terms of energy consumption, but allow operation in a narrower temperature range. Another disadvantage of external mixing systems is the high sensitivity of snow guns to wind. External mix systems require 30% more snow grooming work compared to internal mix/fan systems. Such systems are recommended for narrow trails and trails that open later. When choosing the type of snow guns, not only the initial cost of buying snow guns is taken into account, but also the cost of the system itself (towers, pumping / compressor stations). The efficiency and the possibility of using this type of snow guns in specific slope conditions are also taken into account. This takes into account the temperature of the snow, the type of terrain, the width of the track, the desired date for the start of the season, the requirements for the noise level.

Table 1. Advantages and disadvantages of certain types of snowmaking systems

2. Artificial reservoirs

Getting snow requires a significant amount of water. To create a snow cover 16 cm thick on an area of ​​60 by 60 m, 277,500 liters of water are required. Such a significant demand for water resources is often a problem for ski centers, since water sources with a significant supply of water are required. Water abstraction from natural sources during the winter season with low flow rates can harm nature. To protect the inhabitants of water bodies and the possibility of using small streams and rivers, artificial reservoirs of snowmaking systems are usually created. The use of artificial reservoirs also makes it possible to minimize the cost of transporting water through pipelines. Such savings due to the forces of gravity are possible provided that the reservoir is located above the installation level of the snowmaking system. At the same time, the costs of building an artificial reservoir are paid off by saving electricity for raising water for several years.

3. Wet/Dry Bulb Temperature

The temperature of the dry bulb is taken as the ambient temperature. Relative humidity is a quantitative indicator of the content of water vapor in the atmosphere. The relative humidity of the ambient air plays a very important role in snow production. An increase in the amount of water vapor in the air leads to a decrease in the rate of cooling of water droplets to nucleation temperatures (crystal formation). When spraying water droplets into the air at low humidity, that is, at a low content of water vapor, part of this water evaporates and thereby cools the surrounding air, because. In order to evaporate water, it must be heated until the latent heat of evaporation is reached. It takes 539 calories to evaporate 1 liter of water, while it only takes 80 calories to freeze it. This means that the evaporation of one liter of water allows you to freeze 6.7 liters of water at a temperature of 0 ° C (it takes only 1 cal. to cool water by 1 ° C and this is the reason that the temperature of the water does not affect the thermal balance too much snow production process).

As a first approximation, the cooling effect of the evaporation process can be taken as follows: a decrease in the actual dry bulb temperature by 0.5 °C for every 10% drop in relative humidity. Examples:

Air at -2°C and 50% RH has the same cooling capacity as saturated air (100% RH) at -4°C.

Air at 0°C and 40% relative humidity has the same cooling capacity as saturated air at -3°C.

Wet bulb temperature (humidity temperature) takes into account two factors at once - ambient temperature and relative humidity, which is why this parameter is used when designing snowmaking systems. The wet bulb temperature is the temperature of the microdroplets coming out of the nozzles of the snow gun, which is reached when all heat exchange processes with the environment are completed. All automatic systems (including water management) installed in western European countries typically start producing snow at -4°C wet bulb. At the same time, it is believed that the production of snow at higher temperatures is unproductive and unreasonably expensive. Only a few resorts located in the warmer parts of Europe, such as Spain and Portugal, start producing snow at -2°C wet bulb, as there is no other choice.

4. Special additives

To form water crystals at high ambient temperatures, special water additives are used. The molecules of such additives play the role of nuclei (seeds), around which the formation of crystalline structures takes place. As mentioned above, this process of crystal formation is called heterogeneous nucleation. As special additives, special proteins (proteins) are used. Such additives save energy and produce good quality snow at marginal temperatures. The decision to use special additives usually depends on the purity of the water used and the presence / absence of natural substances in it that contribute to the crystal formation process. Often, water from natural reservoirs already contains a sufficient amount of the necessary substances, and, therefore, the use of additives is not required.

5. Cooling systems

At water source temperatures above +5°C, special cooling systems are used to cool the water before it is fed to the snowmaking system. A decrease in water temperature has a positive effect on the efficiency of snow formation by reducing energy losses for water evaporation. Cooling systems can have various designs and principles of operation. Both cooling towers (cooling towers) and once-through cooling systems can be used. The use of cooling towers allows the ski season to open earlier and produce snow at higher ambient temperatures.

6. Management of snowmaking systems

One of the important points when choosing equipment for a snowmaking system is the choice of the type of control, since further operating costs will largely depend on this.

Description of work and advantages of automatic systems:

Information about the weather conditions of the environment (humidity, temperature, wind speed and direction) is supplied as a standard analog or digital signal to the control system. The automation system evaluates the weather conditions and automatically (without the participation of the operator) regulates the technological parameters of the snow production process. The operator, if desired, can also use a computer to set the operating parameters of the process. Automatic control allows you to significantly reduce the cost of pumping water and air (no need for unnecessary pumping of excess) and maintenance of the system. The time needed to set up the system is greatly reduced, since the response time of the system components is only a fraction of a second. At the same time, the efficiency of automatic systems with internal mixing and fan systems increases by 30-50% compared to manual systems.

For systems with external mixing, the increase in efficiency is negligible, since such systems do not require constant adjustments. With sudden changes in weather conditions, it may be necessary to move from one area to another with snow. The software allows the operator to easily concentrate on such tasks, while adapting to weather conditions is provided by the system itself. The control system automatically adjusts the water pressure to adapt the snowmaking system to the weather conditions. Moreover, the automatic air compressors regulate the pressure in the air line and, if necessary, distribute the load between the compressors, and turn them on / off depending on the air demand of the system. The software allows continuous monitoring of process parameters (water temperature, water and air flow/pressures).

Manual systems take one to four hours to start up and one to three hours to shut down. At the beginning of the season, the time intervals during which it is possible to produce high-quality snow are from 6 to 8 hours. Starting and shutting down automatic systems takes seven to fifteen minutes. Automatic systems continuously monitor the quality of the snow produced by continuously adjusting the operating parameters of the snow guns. Manual systems, on the other hand, require control and adjustment by qualified personnel directly at the installation site of snow guns in case of changing weather conditions, which negatively affects the quality of snow and increases its cost. The increase in the operational efficiency of snowmaking systems compared to manual systems is 40-60%.

The reliability and safety of the systems are the determining factors when choosing the type of control, since the systems use very high water and air pressures. A properly installed automation system allows you to control these parameters without operator intervention in the operation of potentially dangerous elements of the systems. The system of instant notification of emergency situations and the state of the equipment allows the operator to immediately correct the operation of the system.

Finally, automation systems create archival report files on all aspects of the snow generation process (electricity consumed, water resources consumed, quantity and quality of snow produced, as well as economic analyses).

7. Air compressors

The presence of an air compressor system is often an essential condition for the existence of a snowmaking system. Compressed air, when it leaves the nozzle of the snow generator, serves to obtain a dispersion of microdroplets in the air. These microdrops are the "heart" of future snowflakes. For systems with internal mixing, the use of compressed air is a prerequisite for obtaining an air-to-water mixture. For such systems, the process of formation of snow crystals depends on the duration of the presence of droplets in the air and on the cooling effect during the expansion of the water-air mixture at the outlet of the nozzle. External mixing systems and fan systems are based on these same physical laws.

The main source of energy consumption in snowmaking systems is air compressors. Typically, 40-70% of energy consumption is accounted for by air compressors and their automation. Air compression systems consist of compressors, an air supply system, automation elements and, sometimes, systems for storing compressed air. The initial cost of purchasing air compressors is only part of the underwater capital cost iceberg, as the annual energy bill is comparable to the cost of purchasing the compressors themselves. Therefore, it is very important for snowmaking systems to choose a compressor with high efficiency and efficiency. The tightness of air supply systems also plays an important role, since if it is leaky, losses of up to 20-30% of the produced compressed air are possible.

8. Pipelines

Particular attention in mechanical snowmaking systems is given to pipelines, on which the quality, reliability and durability of the entire system largely depend. European companies, based on many years of operating experience and taking into account the specifics of installation in mountainous conditions, have developed special types of pipes, technologies for laying and connecting them, providing an optimal ratio of speed, quality and costs for the water supply system.

For example:

When using relatively expensive quick-disconnect pipes with external and internal plastic coating and a 30-year service life, high water quality, maximum speed and minimum cost of construction work and further operation are ensured, since there is no need for long-term use of special equipment. technicians, highly qualified assemblers, welders, seam testing, etc.

When using the cheapest welded, long and heavy "black" pipes, not specifically designed for use in rugged terrain (the laying of which requires special equipment capable of working on rocky soils with large slopes, special technologies for high-quality welding, "anchoring", installation, waterproofing, etc.) not only increases the total cost of building a water pipeline by 3-4 times, but because of the low service life (about 5 years) and water quality (rust), the operating costs for all equipment of the mechanical snowmaking system as a whole (pumping stations, hydrants, snow guns) increase sharply.

The best option at a low initial cost and acceptable quality (if the timing of favorable weather conditions for the work) are light socket welded galvanized pipes. But the expediency of their application must necessarily be determined on the basis of the specifics of the local conditions in each specific case.

We hope that the above data will convince potential investors and organizers of modern ski centers that when installing mechanical snowmaking systems, it is necessary to take into account all factors related to both the technique and the place where the system will be mounted. In addition, the mechanical snowmaking system always needs to be installed and maintained ONLY by professionals and "amateur" in this process is unacceptable.

To draw up a feasibility study The organizer of the ski route must submit a topographic survey of the area on a scale of M 1:1000 or M 1:2000 with the following data:

Areas to be covered with snow;

Schemes of ski slopes and infrastructure buildings;

Place and nature of water intake (debit of water cubic meters per hour);

Time for initial snow making with 30cm snow layer thickness (usually taken 50-200 hours);

Data on air temperature and humidity or wet bulb temperature (to start the system at the beginning of the season, to work during the season);

Data on prevailing wind direction and speed;

The degree of automation of the system (manual, semi-automatic, fully automatic centralized).

To plan ANY investment, both in size and timing, in a mechanical snowmaking system, several factors MUST be considered, namely:

1. Any ski complex that claims to be used intensively and efficiently needs mechanical snowmaking systems.

Even in areas with sufficient natural snow cover, the use of mechanical snowmaking systems allows not only to extend the season by at least a month, increasing profitability, but also ensures the stability of planning and holding various events and competitions, guarantees the presence of stable snow cover on tracks with intensive use, allows you to create specialized snow structures (slides, wide start- finish", etc.), which, in turn, dramatically increases the liquidity of the complex as a whole. And in the conditions of "global warming", the use of mechanical snowmaking systems becomes especially important.

2. Snowmaking system is a complex of engineering structures and devices, which necessarily includes:

An artificial reservoir for storing water (if there is no natural one - lakes or rivers);

Water intake (submersible, borehole pumps);

Water filtration system;

Equipment for cooling water (cooling tower or once-through cooling), if necessary;

Main pump/compressor stations (the pump station can be mobile, in some types of snowmaking systems the compressors are mounted directly on the guns)

Water/air supply (pipelines, hydrants, drainage system)

Measuring equipment (weather and wind stations, pressure and water / air flow control devices, etc.)

Snow guns of various types (water-air with internal and external mixing, fan multi-nozzle and with a central nozzle), stationary or mobile

Snowmaking control systems (PLC (programmable logic controller) units, control cables or fiber optic network, PC in centralized control, radio control modules)

Power supply from the transformer substation (connectors for connecting guns, electric power cable).

Snowstar mechanical snowmaking systems. Design, installation, repair, service.

The official representative of Snowstar in Russia is the Gorimpex Group of Companies.

Artificial snow is very popular in our time for shows, various holidays, events, weddings and anniversaries. It is used in performances as scenery, for decorating shop windows, and in the interior of bars and restaurants, snow will also find application. It does not stain clothes, is non-toxic, and looks exactly like the real thing.

How to make artificial snow with your own hands

Most importantly, you will need a liquid concentrate or a special powder. It is mainly produced by foreign manufacturers.

To make artificial snow with your own hands, you need to add ordinary water to this powder or concentrate, and after that it increases in volume by almost a hundred times. Such artificial snow is stored for several days. After the confluence of time, it begins to dry out and decrease in volume. If you collect it all and add water again, it will return to its previous state. Artificial snow is easily washed off and does not stain the surface.

snow cannon

It will be very easy to cover beautiful snowdrifts in just a few seconds. In order to get the effect of a blizzard or falling snow, an air gun and a special snow generator are used. The generator is a special device, the weight of which is from eleven to twenty kg. But there are installations for artificial snow of an even larger size - from forty kg. Such a snow generator works on a concentrate that is previously diluted with water. The concentrate is supplied from America, and it is certified. One liter of water is enough for an hour of operation of such an installation. The size and shape of snowflakes can be programmed in advance. The dispersion of snowflakes is up to fifteen meters.

Video: Comparative test of snow guns.

The price of a snow cannon is 150.000-1.000.000 rubles. The cost depends on its performance. They are mainly used for ski slopes. To begin with, it is better to buy the most inexpensive snow generator. It can also be rented out. The cost of rent per hour of work ranges from two to five thousand rubles.