EP3587966A1 - Artificial snow production system and snow production method - Google Patents

Abstract

A snow-making system (10) has a snow-making assembly (12) and a refrigerator (14). The snow-making assembly (12) is designed to receive snow-making water (B, K) and has one or more nozzles (20.x) for expelling the snow-making water (B, K) and / or a mixture of air and the snow-making water (B, K) on. The refrigeration machine (14) has at least one cooling circuit (22) which contains a refrigerant (M) separate from the snow-making water (B, K), the refrigeration machine (14) being set up to remove the snow-making water (B, K) before cooling the snow making assembly (12). A snowmaking process has corresponding features.

Description

The present invention relates to the field of technical snow production, for example for winter sports both outdoors (e.g. ski slopes, cross-country ski trails, ski jumps) and indoors (e.g. ski halls).

In the course of climate change, technical snow production is becoming increasingly important. Most of the systems used for large-scale snowmaking can be classified into the main groups of fan guns (so-called "snow cannons") or lance snow guns. These systems require a wet bulb temperature (cooling limit) of the ambient air of theoretically a maximum of 0 ° C and in practice below 0 ° C. In these known systems, water is sprayed into the ambient air by means of at least one water or water / air nozzle. For example, the water can come from a storage lake or storage basin for supplying many propeller machines or lance snow producers and can be cooled by means of at least one evaporative cooling tower which is constructed in the vicinity of the storage lake or basin.

In the systems just mentioned, the water used to produce snow ("snow-making water"), when it is fed to the at least one nozzle, typically has a temperature of a few degrees above 0 ° C. After exiting the nozzle, the finely sprayed water in the ambient air quickly cools down to freezing point (approx. 0 ° C) and freezes. The heat released in the process is at least partly dissipated by evaporative cooling, a part of the water emerging from the nozzle evaporating. The formation of snow crystals starts with nucleation nuclei, which are usually formed by rapid subcooling of water with the help of expanding air at the above-mentioned water / air nozzles or special nucleator nozzles operated with compressed air.

In the systems described above, however, the snow formation in the border area, that is to say at air temperatures close to the possible maximum value, in particular in combination with a relatively high snow-making water temperature, is problematic.

Systems are also known in which technically cooled air is used. For example, shows EP 1 600 711 A2 an indoor snow system with nozzles, to which dry compressed air with a temperature of well below 0 ° C and water with a temperature of around 0 ° C are supplied. Furthermore, the interior (indoor ski area) is cooled to a temperature in the range of 0 ° C by air conditioning. In other known systems, small ice crystals are formed inside a machine, for example in the system according to CN 107024049 A , However, these systems are complex and consume a lot of energy, so that they are not practical for large-scale applications, for example for the snowmaking of entire ski slopes or outdoor ski areas.

There is therefore a need for a technique which is relatively inexpensive on the one hand and on the other hand has good snow-forming properties at temperatures in the border area.

According to the invention, this object is achieved by the features of the independent claims. The dependent claims define optional features of some embodiments of the invention.

The invention is based on the knowledge that in snow-making systems with at least one water or water / air nozzle, the snow-forming properties are particularly good if the water expelled from the at least one nozzle soon changes to the freezing temperature (approx. 0 ° C, depending on the prevailing air pressure) or in some configurations this temperature is already present when it emerges from the nozzle. The colder the water ejected from the nozzle, the less heat needs to be dissipated, and the easier it is for the nucleation seeds to form the basis for the snow crystals.

The invention therefore proposes a snow-making system that has a snow-making assembly and a refrigerator. The snow production module can be a snow generator known per se (for example in the form of a propeller machine or as a lance snow generator) be or at least be derived from such a known snow gun within the scope of the usual professional skill. The chiller as such is either known per se or derived from a known chiller within the scope of the skilled person. The invention is primarily seen in the combination of the snow making assembly and the chiller.

In the snow-making method according to the invention, there is also the combination of the steps that snow-making water is cooled by means of a refrigeration machine, and that the snow-making water cooled by the refrigeration machine and / or a mixture of air and the snow-making water cooled by the refrigeration machine through one or more nozzles of a snow-making machine. Assembly is / are ejected.

The combination according to the invention leads to considerable and surprising advantages. In particular, snow can be efficiently produced in good quality even at limit temperatures - i.e. at wet bulb temperatures in the range of at most 0 ° C to just below 0 ° C. However, the invention is not restricted to this temperature range. If the snow-making water is subcooled in some configurations, it is even possible to produce snow at wet bulb temperatures of slightly above 0 ° C.

The system according to the invention also has advantages at temperatures below the absolute limit range. It has been shown in practice that known installations with cooling towers do not always work satisfactorily even at temperatures below the absolute limit range. Even in cold weather conditions, it is not possible to feed strongly supercooled water into the lines that run from the storage lake or pool to the snow guns, since otherwise the lines could ice up. However, if the water fed in has a temperature of around 0 ° C, it heats up to a few degrees above 0 ° C due to geothermal energy until it arrives at the snow guns. This is particularly true in early winter because of the warmer soil, when technical snow production is particularly important to create a good snow base. There is also an open cooling circuit in the case of evaporative cooling, which must necessarily be arranged in front of the feed pumps to the snow guns. The power loss of the pumps then leads to a further heating of the snow-making water.

In the known systems, the effects just mentioned can lead to the fact that the snow-making water arriving at the snow-making equipment is warmer than it would be desirable for good snow production even in cold weather conditions. At ambient temperatures in the border area, this is practically always the case, because the evaporative cooling towers require a few degrees of temperature difference between the wet bulb temperature and the temperature of the snow-making water that can actually be achieved by evaporative cooling, and then the above-mentioned heating on the way to the snow-making equipment and through the pumps and pipes come in addition.

The solution according to the invention enables efficient water cooling to a desired temperature range - which is generally lower than would be achievable with known systems at limit temperatures. For example, embodiments of the invention can be designed such that, in all weather conditions that are suitable for snow production at all, the snow-making water exits the one or more nozzles and has a temperature of at most 4.0 ° C. and preferably at most 2.0 ° C. and more preferably at most 1.0 ° C. These temperature ranges already represent a considerable advantage over the prior art.

In some embodiments, it is even provided that the snow-making water is subcooled by the refrigeration machine, so that it has a temperature of less than 0.0 ° C. when it emerges from the one or more nozzles. In the latter case, nucleation nuclei form immediately upon exiting the nozzle or nozzles, which are then immediately in thermal equilibrium with the droplets of the snow-making water which is expelled. In contrast to systems that work with higher water temperatures and form nucleation nuclei, for example through expansion of compressed air, there is no danger in the exemplary embodiments just described that the nucleation nuclei formed dissolve again in the warmer other snow-making water and thus the snow production is restricted.

When the claims speak of the snow making assembly "having one or more nozzles for ejecting the snow making water and / or a mixture of air and the snow making water", it does not necessarily mean that all the nozzles of the snow making assembly are provided for expelling the cooled snowmaking water and / or a mixture of air and the cooled snowmaking water. Rather, the snow-making assembly can also contain further nozzles, which are provided in addition to the “one or more nozzles” mentioned. In some configurations, however, all the nozzles of the snow-making assembly have the claimed properties.

In some configurations, the refrigerator and the snow making assembly are integrated into a single device or assembly. For example, the refrigerator and the snow-making assembly can rest on a common foundation and / or be attached to a common frame and / or be built into a common housing. In other configurations, however, the refrigerator and the snow-making assembly are two separate assemblies. In this case, it can be advantageous if the refrigeration machine and the snow-making assembly are at a relatively small spatial distance from one another, which is, for example, at most 10.0 m and preferably at most 3.0 m. Such a small spatial distance helps to avoid undesired heating of the water cooled by the refrigerator in a line leading to the snow-making assembly. However, embodiments of the invention are also provided in which this distance is greater.

In some configurations, the chiller and the snow making assembly are connected by an (insulated or non-insulated) conduit for the cooled snow water that is in the ambient air and / or within a housing and / or in the ground, but less deep than that Frost depth runs.

In many conventional snow-making systems, a line network is provided which has at least one main water line fed by a storage lake or basin and a plurality of branch lines branching off from it. In some embodiments of the invention a similar pipeline network exists and the chiller is on the same branch line as the snow making assembly.

In some configurations, the snow-making system has a plurality of snow-producing assemblies and a plurality of refrigeration machines, each of which is individually associated with one another (ie in a 1: 1 relationship). In other words, in these systems there are several pairs of exactly one chiller and exactly one snow-making module, so that the chiller only supplies its assigned snow-making module with cooled snow-making water, and the snow-making module is exclusively supplied by this chiller. This does not rule out the fact that in such systems there are further snow-making assemblies and / or further chillers that do not have the aforementioned 1: 1 relationship.

In some embodiments, the snow-making water is already under pressure in the refrigerator, for example under at least half the operating pressure. In particular, these can be embodiments in which the snow-making system does not have its own feed pumps for the snow-making water, so that the inlet pressure of the snow-making water in the refrigerator is approximately as high or (due to the pressure loss in a heat exchanger of the refrigerator through which the snow-making water flows) somewhat higher than the operating pressure is. In some configurations, the operating pressure can be more than 2 bar or preferably more than 5 bar or even more preferably more than 10 bar.

As already mentioned, the refrigeration machine and / or the snow-making assembly can be designed as such in various ways which are known per se or obvious. For example, the refrigerator can have an economizer and / or an intermediate cooling circuit. The snow making assembly may further include at least one water jet pump, as shown in FIG EP 1 456 588 B1 is described. In general, in many configurations, the snow-making assembly is set up to work in uncooled and / or uncompressed ambient air.

In some configurations, the snow-making system is set up to only expel snow-making water, which has been cooled by the refrigerator, at least in some temperature conditions. In other embodiments, however, additional water that is not cooled by the refrigerator is expelled. This make-up water can, for example, come directly from a storage lake or pool, whereby evaporative cooling can take place, but does not necessarily have to take place. Such embodiments can have a high maximum output with particularly good efficiency.

Further features, objects and advantages of the invention will become apparent from the following detailed description of exemplary embodiments of the invention, in conjunction with the accompanying schematic drawings, in which the drawing figures 1-6 each show an embodiment of a snow-making system according to the invention. It goes without saying that the following description of exemplary embodiments serves to explain aspects and refinements of the invention and should not be interpreted as a restriction of the scope of protection.

In 1-6 A snow-making system 10 is shown in each case with a snow-producing assembly 12 and a refrigeration machine 14, which are connected to one another by a line 16 for cooled snow-making water K. The refrigeration machine 14 is in turn fed by snow-making water B from a storage lake or a storage basin (not shown) which, in the exemplary embodiments described here, is not cooled or at most is cooled by central evaporative cooling. It goes without saying that the invention is not restricted to snow-making systems 10 with a single snow-producing assembly 12 and a single refrigeration machine 14, even if such systems are primarily described below for better understanding. Rather, snow-making systems 10 according to the invention can have a plurality of snow-producing assemblies 12 and / or a plurality of refrigeration machines 14 and / or further components, such as, for example, a line network (not shown in the figures) with a main line and a plurality of branch lines.

The snow-generating assembly 12 has at least one nozzle assembly 18, which according to the exemplary embodiments described here 1-6 in each case a plurality of nozzles 20.1, 20.2, 20.3, ... - hereinafter referred to collectively as "20.x" - contains. In general, each of the nozzles 20.x can be designed as a water nozzle or water / air nozzle or in special other designs (for example as a nucleator nozzle). The water or water / air mixture expelled from the nozzles 20.x or at least some of the nozzles 20.x is cooled snow-making water K or has at least a portion of cooled snow-making water K. In the embodiments described here, the nozzles 20.x are in uncompressed ambient air or, in the case of propeller machines, in the air jet generated by the propeller, which is also to be understood as “uncompressed ambient air” in the wording used here. If the snow-making system is installed outdoors, the ambient air is also uncooled. If the snow-making system is installed indoors (e.g. in a ski hall), the entire ambient air in the ski hall may have been cooled, but there is no additional cooling in connection with the snow-making system. This should also be understood in the choice of words used here as "uncooled ambient air".

The snow generation module 12 can be configured in various known designs, for example as a propeller machine (“snow cannon”) or as a lance snow generator.

Fig. 1 shows a particularly simple embodiment of the snow production module 12, in which only water nozzles 20.x are provided which only eject cooled snow-making water K into uncompressed and uncooled ambient air. More complex embodiments are the subject of Fig. 2-6 and are described below.

The refrigeration machine 14 has, in a manner known per se, a cooling circuit 22 which contains a refrigerant M which is separate from the snow-making water B, K. In 1-4 the basic form of a refrigeration machine 14 is shown schematically, in which a first heat exchanger 24, a throttle element 26, a second heat exchanger 28 and a compressor 30 are provided. The first heat exchanger 24, which can be designed, for example, as a condenser, dissipates heat from the refrigerant M to the environment. Depending on the type of refrigerant M, the refrigerant M can condense in some configurations, while in other embodiments there is no phase transition. The throttle body 26 reduces the pressure of the refrigerant M. The refrigerant M is therefore able to extract heat from the snow-making water B supplied in the second heat exchanger 28, which can be configured, for example, as an evaporator. This results in the cooled snow-making water K. The heated and possibly now vaporous refrigerant M is fed back to the first heat exchanger 24 via the compressor 30, whereby the cycle is closed.

In general, the various configurations of the snow making assembly 12 as shown in 1-6 are shown and described here, arbitrarily with the various configurations of the refrigeration machine 14, as also shown in FIG 1-6 shown and described here can be combined. The invention thus includes, for example, at least all snow-making systems in which any snow-making assembly 12 according to one of the drawing figures 1-6 with any chiller 14 according to another of the drawings figures 1-6 is used.

In Fig. 2 A modified snow-making system 10 is shown, in which the nozzle assembly 18 is supplied with a mixture of air and the cooled snow-making water K by a water jet pump 32. The nozzles 20.x are designed as water / air nozzles. The cooled snow-making water K serves as a driving medium for the water jet pump, which in turn sucks in uncompressed ambient air at an inlet 34 and mixes this air with the cooled snow-making water K. The snow / air mixture thus produced is expelled through the nozzles 20.x. This principle of operation is off as such EP 1 456 588 B1 known. It goes without saying that, in further modifications, a plurality of nozzle assemblies 18, each having a plurality of nozzles 20.x, can be provided.

This in Fig. 3 snowmaking system 10 shown is similar to the system of FIG Fig. 1 , however one or more of the nozzles 20.x - in Fig. 3 the nozzle 20.3, for example, is designed as a nucleator nozzle for generating freeze nuclei. The nucleator nozzle 20.3 is supplied with the cooled snow-making water K and with compressed air, which in turn is obtained from ambient air by means of a compressor 36.

Fig. 4 shows an example of a snow-making system 10 with a plurality of nozzle assemblies 18, which are supplied partly by the cooled snow-making water K and partly by make-up water Z. The make-up water Z comes from the same main and branch line as the cooled snow-making water K, but the make-up water Z is not cooled by the refrigeration machine 14. In the in Fig. 4 In the example shown, a hydraulic connection 40, for example a controllable or permanently set throttle element or a controllable or permanently set valve, is also provided for mixing the cooled snow-making water K and the make-up water Z, while in other configurations there is no such connection.

When the hydraulic connection 40 is closed, or when there is no hydraulic connection at all, the nozzles 20.1-20.9 are supplied exclusively with cooled snow-making water K, and the nozzles 20.10-20.15 are supplied exclusively with make-up water Z. This is particularly advantageous if the snow-making system 10 has a relatively long throw for the additional water Z expelled from the second-mentioned nozzles 20.10-20.15, because this water can then cool in the ambient air before it is completely or partially frozen Snow-making water K of the nozzles 20.1 - 20.9. When the hydraulic connection 40 is completely or partially open, the nozzles 20.x, on the other hand, are supplied with a mixture of the cooled snow-making water K and the additional water Z — optionally in variable mixing ratios. It is understood that in further configurations, several hydraulic connections 40 - e.g. controllable valves or permanently set mixers - can be provided in order to produce different mixtures of the cooled snow-making water K and the make-up water Z, which are directed to different nozzle assemblies 18.

The nozzle assemblies 18 in Fig. 4 are shown partly with and partly without water jet pumps 32. It goes without saying that this is only an exemplary arrangement, and that many further configurations in which make-up water Z is used are possible and provided. Furthermore, in Fig. 4 Each nozzle assembly 18 is assigned a valve 38 with which the water supply to this nozzle assembly 18 depends on the operating conditions can be adjusted. This enables a good adaptation to a wide variety of operating situations and weather conditions.

In the Fig. 4 Concepts illustrated by way of example, namely the use of make-up water Z and / or the use of at least one hydraulic connection 40 and / or the use of several individually controllable nozzle assemblies 18, can of course also be combined with the other configurations of the snow-generating assembly 12 described here, for example with the use of nucleator nozzles Fig. 3 ,

5 and 6 show modifications of the refrigeration machine 14, which can be combined with all the configurations of the snow-making assembly 12 described here. This is the case with the refrigeration machine 14 according to FIG Fig. 5 an economizer 42 is provided in the cooling circuit 22, that is, a further heat exchanger which increases the efficiency of the refrigeration machine 14 because it heats up refrigerant M, which comes from the second heat exchanger 28, before the compressor 30. In the refrigerator 14 according to Fig. 6 an intermediate circuit 44 with a further heat exchanger 46 and a pump 48 is provided. The intermediate circuit 44 has a cooling medium MM which differs from the refrigerant M in the cooling circuit 22. For example, the cooling medium MM can be a water / glycol mixture. The use of an intermediate circuit 44 has in particular the advantage of increased design freedom in the design of the refrigeration machine 14.

In a first operating example, a snow-making system 10 of the type described above receives snow-making water B with a temperature of approximately 4 ° C.-8 ° C. The refrigeration machine 14 produces cooled snow-making water K with a temperature of 0.0 ° C. Taking into account a slight heating of the snow-making water K in the line 16 and the nozzle assemblies 18, the snow-making water K, when it flows through the nozzles 20.x (as water or as a water / air mixture), has a temperature of approximately 0.5 ° C. At a temperature of the ambient air of slightly below 0 ° C, nucleation nuclei form immediately, to which the remaining snow-making water K quickly accumulates in the form of a snowflake.

In a second operating example, the refrigerator K produces supercooled snow-making water K with a temperature of -1.5 ° C. This snowmaking water K, when it passes through the nozzles 20.x and exits them, has a temperature of approximately -1.0 ° C. Snow formation occurs almost immediately at ambient temperatures below 0 ° C. Snow can still be produced even when the ambient air temperature is slightly above 0 ° C.

It goes without saying that these operating examples are only intended to serve as examples for a better understanding of the invention, and that other operating parameters may be expedient depending on the ambient conditions.

The details contained in the above description of exemplary embodiments and operating examples are not to be understood as restricting the scope of the invention, but rather as an exemplary illustration of some embodiments. Many variants are possible and immediately apparent to the person skilled in the art. In particular, this relates to modifications that have a combination of features of the individual exemplary embodiments. Therefore, the scope of the invention should not be determined by the illustrated embodiments, but by the appended claims and their equivalents.

Claims (15)

Snow-making system (10), comprising: a snow-making assembly (12) adapted to receive snow-making water (B, K) and one or more nozzles (20.x) for expelling the snow-making water (B, K) and / or a mixture of air and the snow-making water (B, K), and a refrigeration machine (14) with at least one cooling circuit (22) which contains a refrigerant (M) separated from the snow-making water (B, K), the cooling machine (14) being set up to remove the snow-making water (B, K) before it the snow making assembly (12) is fed to cool. Snow-making system (10) according to claim 1, characterized in that the refrigeration machine (14) and the snow-making assembly (12) are at a spatial distance of at most 10.0 m and preferably at most 3.0 m from one another. Snow-making system (10) according to claim 1, characterized in that the refrigerator (14) and the snow-making assembly (12) are integrated into a single assembly. Snowmaking system (10) according to any one of claims 1-3, characterized in that the snowmaking system (10) further comprises a line network with at least one main water line, from which several branch lines branch off, and further characterized in that the refrigerator (14) and the Snow making assembly (12) in the same branch line. Snow-making system (10) according to one of Claims 1-3, characterized in that the snow-making system (10) has a plurality of snow-making assemblies (12) and a plurality of cooling machines (14), one of the snow-making assemblies (12) in each case one of the plurality of chillers (14) is individually assigned. Snowmaking system (10) according to any one of claims 1-5, characterized in that the refrigerator (14) is set up to cool the snowmaking water (B, K) to a temperature which is lower than the respective wet bulb temperature in the vicinity of the refrigerator ( 14) is. Snowmaking system (10) according to any one of claims 1-6, characterized in that the refrigeration machine (14) is set up to cool the snowmaking water (B, K) to such an extent that the snowmaking water (B, K), if there is one or passes through the plurality of nozzles (20.x), has a temperature of at most 4.0 ° C and preferably at most 2.0 ° C and even more preferably at most 1.0 ° C. Snowmaking system (10) according to any one of claims 1-6, characterized in that the refrigeration machine (14) is set up to cool the snowmaking water (B, K) to such an extent that the snowmaking water (B, K), if there is one or which passes through a plurality of nozzles (20.x), has a temperature of less than 0.0 ° C. Snow-making system (10) according to one of claims 1-8, characterized in that the snow-making assembly (12) is set up to receive the snow-making water (B, K) at an operating pressure, and in that the refrigeration machine (14) is set-up to do so to obtain the snow-making water (B, K) with an inlet pressure which is at least half as high as the operating pressure and preferably at least as high as the operating pressure. Snowmaking system (10) according to any one of claims 1-9, characterized in that the refrigerator (14) has an economizer (42) and / or an intermediate circuit (44). Snow-making system (10) according to any one of claims 1-10, characterized in that the snow-making assembly (12) is set up to provide the snow-making water (B, K) and / or the snow-making water / air mixture in ambient air, preferably in to expel uncooled and / or uncompressed ambient air. Snow-making system (10) according to one of claims 1-11, characterized in that the snow-making assembly (12) further comprises at least one water jet pump (32) which is set up to cool the snow-making water (B, K ) as a propellant and to draw in uncompressed ambient air and mix it with the snow-making water (B, K), and which is also set up to produce the snow-making water / air mixture produced by the one nozzle (20.x) or, if the snow-making assembly (12) has a plurality of nozzles (20.x) to feed at least one of these several nozzles (20.x). Snowmaking system (10) according to any one of claims 1-12, characterized in that the snow-making assembly (12) is further configured to make additional water (Z), which also through the one or more nozzles (20.1 - 20.9) or at least Another nozzle (20.10-20.15) is to be ejected, the make-up water (Z) not being cooled by the refrigeration machine (14). Snow-making system (10) according to claim 13, characterized in that the snow-making assembly (12) has a hydraulic connection (40) for mixing the additional water (Z) with the cooled snow-making water (K). Snowmaking process, with the steps: Cooling snow-making water (B, K) by means of a cooling machine (14), the cooling machine (14) having at least one cooling circuit (22) which contains a refrigerant (M) separated from the snow-making water (B, K), and Ejecting the snowmaking water (B, K) cooled by the refrigerator (14) and / or a mixture of air and the snowmaking water (B, K) cooled by the cooling machine through one or more nozzles (20.x) of a snow-making assembly (12 ).

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