EP3425311B1 - Method and device for producing artificial snow - Google Patents

Description

The present invention relates to a method for producing artificial snow according to claim 1.

In order to produce artificial snow, it is generally known to provide a snow gun which produces artificial snow using compressed air and water or using ventilated air and water. Typically, an air-water mixture is released into the atmosphere, with the water droplets in the air-water mixture cooling and falling to the ground as snow. Such a device is, for example, with the EP 2 232 171 known. The EP 2 232 171 aims at a snow lance. However, conventional snow cannons can also be used to produce snow.

In order to produce artificial snow, the snow generators, that is to say typically snow lances or snow cannons, in particular devices for producing drops or a water mist, are subjected to water. The water is typically taken from a reservoir, such as a reservoir. The removal of water from a flowing body of water is also conceivable. Video document XP054977845 ("SlopeEdge: Behind the Scenes - How Snowmaking at Ski Resorts Works", URL:https://www.youtube.com/watch?v=EQjidiRpVeY) reveals a ski slope with a reservoir, with meltwater from the through snow produced by the snow guns is returned to the reservoir.

The generation of artificial snow, such as in the EP 2 232 171 described, depending on the temperature in the atmosphere but also depending on the water temperature of the water that is needed to produce the artificial snow. Attempts have therefore been made in the prior art to cool the water from the reservoirs in question, for example with cooling towers, so that the water is fed to the snow lances at a lower temperature than in the reservoir. With this The snow guns are charged with cooled water. This makes it possible to start up the snow guns and produce artificial snow even when the outside temperature is relatively high.

Such systems are expensive to produce and expensive to maintain.

It is therefore the object of the invention to eliminate these and other disadvantages of the prior art. In particular, a method and a device for producing artificial snow are to be provided which can also be operated at relatively high temperatures, are individually adaptable, easy to handle and inexpensive to manufacture. In addition, the maintenance and operating costs are preferably reduced.

This object is achieved by the method defined in claim 1. Further advantageous embodiments emerge from the dependent patent claims.

In a method according to the invention for producing artificial snow, water is taken from a reservoir and fed to a first circuit. The first circuit includes at least one snow gun and in particular at least one snow lance. The first circuit is intended for snowmaking at a winter sports location, in particular a ski slope.

• Zuführen von Wasser zu einem zweiten Kreis, umfassend zumindest einen oder mehrere zweite Schneeerzeuger, insbesondere Schneilanzen,
• Erzeugen von Schnee mit dem zweiten Kreis,
• Zuführen des mit dem zweiten Kreis erzeugten Schnees zum Speichersee.

The water in the reservoir is cooled in the following steps:

• Supplying water to a second circuit, comprising at least one or more second snow guns, in particular snow lances,
• creating snow with the second circle,
• Feeding the snow produced with the second circuit to the reservoir.

Here and in the following, a circle is understood to mean a section of the system that typically has a connection from a reservoir, such as a reservoir, to the snow lance. The reservoir can also be a flowing body of water, for example, from which water is taken. The circle can be open or closed. An open circle means that, for example, the snow that is deposited on a ski slope then seeps away into nature, at the latest in spring. A closed circuit is characterized by the fact that essentially the largest part is led back to the reservoir, in particular to the reservoir.

Here and in the following, the term snowing is also understood to mean impinging on a locality with water droplets that were produced with a snow gun. At high ambient temperatures, typically only part of the water droplets produced is converted into snow, or it is not possible for the water droplets to freeze through.

In the present method, snow is produced with the second snow guns. This means that the second snow guns produce water droplets that are exposed to the atmosphere. The atmosphere extracts heat from the water droplets, so the water droplets are cooled. With desired conditions (e.g. for the snow lance from the EP 2 232 171 at a wet-bulb temperature of approx. -3° C), the water droplets acquire so much energy that they carry out a phase change and freeze in the process. The phase change releases additional energy into the atmosphere.

This snow is fed into the reservoir. In the case not claimed, when only cooled water droplets are supplied to the reservoir, these are heated up by the energy present in the reservoir and the reservoir is cooled at the same time. An equilibrium is established between the water droplets and the reservoir in terms of temperature. In the event that at least some or all of the water drops are frozen, additional energy is withdrawn from the reservoir to melt the snow crystals, so that an equilibrium is also established. This means that the melting enthalpy for melting the snow or ice crystals is also withdrawn from the reservoir. The reservoir is additionally cooled.

In a preferred embodiment, the second snow guns are arranged in such a way that a surface of the reservoir is snowed directly in order to supply the snow produced with the second circuit.

This makes it easy and efficient to bring the snow into the reservoir. A simple cooling is thus made possible.

However, the second snow guns can also be arranged in such a way that the snow produced by the second circuit is temporarily stored in a depot before it is fed to the reservoir.

This enables the reservoir to be filled and thus cooled only when cooling in the reservoir is required. For example, it is possible that the conditions for snowing the reservoir are favorable, the cooling of the reservoir but is not desired because, for example, the lake already has a low temperature or the winter sports location is already in good condition and snowmaking is not necessary for the winter sports location.

This means that the medium required to cool the lake is temporarily stored. Provision can be made to store the medium required for cooling the lake over a longer period of time, for example from spring to autumn.

Provision is advantageously made for the contents of the reservoir to be circulated, and preferably circulated continuously, so that the individual layers of water in the reservoir mix with one another.

This makes it possible to lower the overall temperature in the reservoir and to achieve an even temperature level.

It is also conceivable that the content of the reservoir is in particular continuously circulated in such a way that the water in the reservoir is fed to an area of the reservoir that has been snow-covered by the second snow gun. This ensures that the entire contents of the reservoir will be covered with snow over time, i.e. the snow gun will be applied. The water of the second circuit is preferably taken from the reservoir.

This creates a closed circle. The water in the reservoir is continuously circulated and further cooled.

Provision can be made for the water to be removed from the reservoir close to the surface using a removal device. This is the first thing to be cooled when making snow. The water near the surface typically has a temperature of around 0°. As explained above, the temperature of the water has a major impact on the efficiency of snow production.

It can be provided that the position of the withdrawal device of the first and/or the second circuit in the reservoir can be variably arranged such that its position in relation to a surface of the reservoir can be adjusted. For this purpose, it can be arranged, for example, in a floating manner or on a floating body.

It is also conceivable to circulate the content of the reservoir depending on the snow production progress. In order to accelerate the cooling, the reservoir cannot be circulated at the beginning of the process to cool only a top layer of the reservoir with supercooled water droplets or ice (snow).

By sucking in this cooler water in the upper area of the reservoir, more ice can be reached faster when snowing and thus faster and more efficient cooling.

Depending on the progress of the cooling, the circulation can start with a time delay from the beginning of the reservoir cooling.

It is also conceivable that the water supplied to the second circuit is taken from another reservoir, for example a flowing body of water. This makes it possible to keep filling the reservoir. Alternatively or in addition Such an arrangement also allows replacing the water taken with the first circuit, which is applied to the winter sports locality as snow, so that a substantially constant level of water is maintained in the reservoir.

A further aspect which is not claimed relates to a device for producing artificial snow, in particular a device for carrying out the method described here. The device comprises a first circuit with at least one snow gun, in particular a snow lance, for making snow on a winter sports location, in particular a ski slope. The first circle can be connected to a reservoir and can be charged with water from it. The device also has at least one second circuit with at least one second snow gun, in particular a snow lance.

The second circuit can be connected to a water source and preferably to the reservoir and can be supplied with water by the latter. The second circle is arranged or can be arranged in such a way that snow can be made on the reservoir.

The device for producing artificial snow preferably comprises a reservoir. The first circuit is also preferably connected to the reservoir. Alternatively or additionally, the second circuit is also connected to the reservoir.

Such a device makes it possible to cool a reservoir without having to provide complex cooling towers.

Preferably, the snow guns of the second circle can be arranged or are arranged on an edge of the reservoir in such a way that the snow produced with the snow gun of the second circle is fed directly to the reservoir. This arrangement is less sensitive to wind influences. Undesirable transport of the snow produced or the water droplets produced can be avoided.

This enables simple and reliable cooling of the reservoir. Transmission losses are minimized.

In a preferred embodiment, the snow guns of the second circuit can be arranged inside and preferably centrally of the reservoir or can be arranged in such a way that the snow produced is fed directly to the reservoir.

It is conceivable that the snow gun is arranged, for example, rotatably on a platform or on a rotatable platform within the reservoir, so that the surface of the reservoir is evenly or continuously covered with snow.

By arranging the snow guns within the reservoir and by appropriate cooling, advantageous temperature distributions can be achieved within the reservoir, which promote circulation of the reservoir.

The device described here preferably has at least one pressure generator for compressed air for operating the snow gun. Also preferably, one or more pumps can be arranged in the first and/or in the second circuit for pumping water to operate the snow gun.

This makes it possible to deliver a complete device that allows the complete snowmaking of a winter sports location. Coordinating the individual components with one another is simplified.

The device can have at least one circulating device for circulating the water in the reservoir. For example, pumps, turbines, propellers or air currents that are introduced into the reservoir can be provided as the circulation device. The individual layers of water in the reservoir can be mixed with one another. This makes it possible to lower the overall temperature in the reservoir and to achieve an even temperature level.

The device can have a line for the second circuit and a line for the first circuit. The line for the second circuit is shorter than the line for the first circuit and preferably shorter than 500 m, in particular shorter than 100 m. For pumping the water in the second circuit and for the operation of the second circuit, less energy is required due to shorter lines with an unchanged cross-sectional geometry of the lines.

Figur 1:

Eine Wintersportlokalität mit einer Vorrichtung zum Erzeugen von Kunstschnee.

Figur 2:

Ein Speichersee im Querschnitt

A device is described by way of example in the following figures. It shows:

Figure 1:

A winter sports location with a device for making artificial snow.

Figure 2:

A reservoir in cross section

figure 1 shows a device for producing artificial snow. The device has a first circuit 100 and a second circuit 200 . These two circles are located in a winter sports locality 1, which has a 2 ski slope. A reservoir 30 is located near the winter sports location 1 . The reservoir has a surface 31 . First snow guns 10 are arranged on one side of the ski slope 2 and are connected to a line 11 for water and compressed air. The line 11 is acted upon by a pump arrangement 12 with water and with compressed air. The pump assembly 12 may include one or more water pumps and one or more air pumps. The water pumps draw the water from reservoir 30.

The second circuit of the device comprises a snow lance 20 and a duct 21 . The line 21 is also charged with water and/or air by means of a pump arrangement 23 . The pump arrangement 23 is designed like the pump arrangement 12 and can have several water and/or air pumps. A water pump of the pump arrangement 23 supplies water from the reservoir 30 to the snow lance 20 . A compressed air pump of the pump arrangement 23 supplies compressed air to the snow lance 20 . Of course, all pumps can be designed separately.

Another second circle 200' is shown. This also includes a pump arrangement 23 and a snow lance 20. In contrast to the second circuit 200, the second circuit 200' is arranged in such a way that the snow produced with the snow lance 20 is fed to a depot 22.

The snow of the second circuit 200 produced with the snow lance 20 is fed directly to the surface of the reservoir.

The snow produced by the snow lance 20 in the second circuit 200 ′ is only removed from the depot 22 at the desired point in time and fed to the reservoir 30 .

Feeding the snow produced with the snow lances 20 to the reservoir 30 cools the reservoir. This makes it possible to produce snow with the first circuit 100 even at higher outside temperatures, since the water in the reservoir 30, in contrast to an uncooled reservoir, has a lower temperature and, after leaving through the nozzles of the snow lances 10, freezes more quickly because the temperature difference is lower . Especially when using the snow lances, as in the EP 2 232 171 described, the lower temperature of the water enables it to be cooled below 0°C more quickly after leaving the nozzles and, when it encounters nuclei, it can freeze rather than melt these nuclei away.

In the case of the second circuits 200 and 200′, however, it can also be provided that the water is not taken from the reservoir 30 but, for example, from a separate reservoir or also from a flowing body of water.

Of course, several first circles 100 and several second circles 200 and 200' are conceivable, which can also be combined in different ways.

Theoretical tests were carried out. These were based on the following material data: substance data density of water r _w 1000 kg/ ^m3 Specific heat capacity of water C _pW 4.2 kJ/kg×K Enthalpy of solidification of water h _WE -334 kJ/kg Specific enthalpies: reference temperature T _Ref 0 °C Water at temperature T _W1 h _W1 42 kJ/kg = c _pW × (T _W1 -T _Ref ) Water in the snow at 0°C h _Sch _ _W 0 kJ/kg = c _pW × (0°CT _Ref ) Ice in the snow at 0°C h _{Sch_E} -334 kJ/kg = c _pW × (0°CT _Ref ) +h _WE Water at temperature T _FK h _{W_TFK} -16.8 kJ/kg = c _pW × (T _FK - T _Ref )

Two cases were considered, on the one hand when the second snow lance snows snow into the reservoir (case a) on the other hand when only cooled water is snowed into the reservoir. reservoir volume of water in the lake V _W1 100'000 m ³ Mean water temperature in the lake T _W1 10 °C mass of water in the lake m _W1 100'000'000 kg Cooling of the reservoir with snow lances Number of snow lances n _L 20 Volume flow per snow lance V ° _L 90 l/min Resulting mass flow of all lances m° _{L_tot} 30 kg/s = _nL ×V° _L × _rW Mass losses (shipping, evaporation) x _v 20% : - cutter t _L 120 H Feeding from the same lake? SP Yes Remaining water mass in the lake at T _W1 m _W2 87'040'000 kg = m _W1 -m _Schn (for SP= Yes) ; = m _W1 (for SP = No) a) Snow lances snow into the lake Mean ice mass fraction in . snow (snow quality) x _E 50% - Estimate over the entire cutting time Resulting snow mass m _Sch 12,960,000 kg = m° _{L_ tot ×} t _L of which water mass at 0°C m _{Sch_W} 5'184'000 kg of which ice mass at 0°C m _{Sch_E} 5'184'000 kg of which losses (shipping, evaporation) m _{Sch_V} 2,592,000 kg Water mass in the lake after snowmaking m _W3 97,408,000 kg =m _W2 + m _{Sch_W} +m _{Sch_E} Total resulting enthalpy in the lake H _{W3_a} 1'924'224'000 kJ =m _W2 ×h _W1 +m _{Sch_W ×} h _{Sch_W} +m _{Sch_E ×} h _{Sch_E} Resulting mean water temperature T _{W3_a} 4.7 °C = H _{W3_a} /(m _W3 *c _pW ) +T _Ref Resulting mean cooling of the lake DT _a 5.3 °C = T _W1 - T _{W3_a} Water volume in the lake after snowmaking V _W3 97'408 m ³ =m _W3 / r _W3 b) Snow lances rain into the lake Mean wet-bulb temperature of ambient air T _FK -3 °C Estimate over total cutting time Resulting water mass with T _FK m _{W_TFK} 10,368,000 kg Total resulting enthalpy in the lake H _{W3_b} 3,525,043,200 kJ = m _W2 × _W1 + m _{W_TFK ×} h _{W_TFK} Resulting mean water temperature T _{W3_b} 8.6 °C = H _{W3_b} /(m _W3 *c _pW ) +T _Ref Resulting mean cooling of the lake DT _b 1.4 °C =T _W1 - T _{W3_b} Water volume in the lake after sprinkling V _W3 97'408 m ³ =m _W3 / r _W3

If the water is not taken from the same reservoir, the resulting temperatures are slightly higher, but the water mass in the lake is also higher.

This calculation does not take into account the withdrawal of water from the operation of the first circuit. The (continuous) removal results in a somewhat deeper cooling, since less and less water has to be cooled over time.

The available data show that an additional cooling of the lake can be generated when it is charged with water droplets from snow lances that have cooled in the atmosphere (with the above data about 1.4°). Additional cooling is achieved when the lake is covered with snow from snow lances (approx. 5.3° with the above data).

The figure 2 shows a reservoir 30 in cross section. A platform 32 is arranged centrally in the reservoir 30 . On this platform 32 is a snow lance 20 of a second circle 200 (see figure 1 ) arranged. In contrast to figure 1 is the snow lance 20 within the reservoir 30. The following statements also apply to the arrangements of the second circles 200 and 200 'from the figure 1 .

The second circuit of the device according to figure 2 has a snow lance 20 and a line 21 . How to figure 1 explained, the line 21 is acted upon by a pump arrangement 23, not shown here, with water and/or air. The line 21 is relatively short, mostly shorter than 100 m. This means that significantly less energy is required to pump water than in the first circuit, where the lines can typically be several kilometers long.

This means that elements of the second circle are regularly dimensioned smaller than elements of the first circle.

The snow lance 20 of figure 2 the platform 32 is designed to be rotatable, which means that during operation it can rotate 360° around its own axis, so that the entire surface 31 of the reservoir 30 can be covered with snow. Additionally or alternatively, a circulating device 40 is provided in the reservoir 30, which circulates the water preferably in the opposite direction to the direction of rotation of the snow lance 20.

However, the circulation device can also be arranged in such a way that water layers which are already cooled or are being cooled on the surface of the lake, with lower layers in the reservoir be mixed. A combination is also possible.

Claims (4)

1. Method for producing artificial snow, wherein

   water is taken from a reservoir (30) for water and fed to a first circuit (100) comprising at least one snow producer (10), in particular a snow lance, for making snow at a winter sports location (1), in particular a ski slope (2), the water in the reservoir (30) being cooled, comprising the steps of

   - Supplying water to a second circuit (200) comprising at least one or more second snow producers (20), in particular snow lances,

   - generating snow with the second circuit (200), characterized by the step of

   - supplying the snow generated with the second circuit (200) to the reservoir (30),

   said second snow producers (20) being arranged in such a way that, for feeding said snow produced with said second circuit (200), a surface (31) of said reservoir (30) is directly snowed, or

   wherein the second snow producers (20) are arranged in such a way that the snow produced with the second circuit (200) is temporarily stored in a depot (22) before being fed to the reservoir (30).
2. Method according to claim 1, characterized in that the contents of the reservoir (30) are circulated, in particular continuously, such that the individual water layers of the reservoir (30) mix with each other.
3. Method according to one of claims 1 or 2, characterized in that the content of the reservoir (30) is circulated, in particular continuously, so that the water located in the reservoir (30) is supplied to an area of the reservoir (30) covered with snow by the second snow producers (20).
4. Method according to one of the claims 1 to 3, characterized in that the water of the second circuit is taken from the reservoir.

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