Snow, artificial

DNAP United States artificial snow / agriculture... 

If snow/ice is stored indoor it is done in a more or less insulated building. In a cavern no insulation except the ground is needed. When the snow/ice is stored on ground or in ponds it is necessary with thermal insulation, henceforth denoted insulation. Both natural and artificial snow and ice may be used and there is no size limitation for snow cooling systems. This snow cooling plant in Sundsvall is an open pond with larger pieces of wood chips as thermal insulation. 

Snow is normally defined as precipitation formed of ice crystals and ice as solid water with hexagonal structure and density about 920 kg m-3. In snow storage the main issue is to have enough amounts of frozen water at low cost why the only relevant distinction is the density. If natural snow or ice is too expensive or not available in enough quantity, it is possible to produce frozen water. Artificial snow and ice made with different types of water sprayers, including snow blowers (snow guns). The production rate depends on equipment, relative air humidity, and temperatures of the air and water. 

Naslund (2000) investigated a district cooling system in Sundsvall, mid Sweden, with sea water and stored snow. The cooling load was 7,900 kW and 7,450-8,560 MWh. Natural snow from streets and squares were complemented with artificial snow made by snow guns or water spraying. The estimated snow proportion was 43.6-66.8% and 122,500m3 of snow was needed. Two layers ofO.Ol mplastic sheets with thermal conductivity 0.04 W m-1 K-1 was recommended as insulation. The plant has not yet been realized (2005). 

Andre et al. (2001) investigated a snow cooling plant in northern Sweden for operation all year round with winter base load 2 MW and summer peak load 6 MW. The idea was to use the local snow deposit and combine with artificial snow. The system consisted of two main ponds and one smaller pond. 

Snow. Both natural snow from streets and squares and artificial snow, made with snow guns, was used. The artificial proportion was 38-59%. The stored snow volumes, measured with a geodetic total station, were 18,800—40,700 m3. The snow density varied from 578-735 kg m-3, with mean density about 650 kg m-3. The first year snow and wood chips were spread with a tractor and an excavator. The other years a snow groomer was used which made spreading much more efficient. 

The amount of artificial snow was calculated as the ratio of water for snow making over estimated snow amount, i.e., snow making loss was not included. 

Electricity depends largely on the amount of artificial snow. The cost of water has decreased due to their private well being used since 2002, on the other hand the electricity usage increased. The municipal water cost was 5 SEK m-3. 

The water availability is important if artificial snow is used. It is however possible to save water in the pond during a period and use it for snow making when the temperature is low enough. It is also be possible to reuse water if pollution problems can be handled. 

In 2006 around 35% of aU ski slopes in the Alps - or roughly 35,000 hectares -were covered with artificial snow. But a comparison with other European countries shows major differences (Fig. 6). If one assumes that 2,000 m of water per hectare need to be used for artificial snowmaking [8], this results in an annual water requirement of 70 million cubic meters for the alpine region as a whole. The estimated volume for Switzerland is around 8.4 million cubic meters. 

In addition to the wide range of effects which artificial snow has on the enviromnent (e.g. [46 9]), the loss of evaporation and sublimation resulting from snow cover or snowmaking is of particular relevance for the water balance of alpine catchment areas. The extent of this loss is still unclear. The data range from 10% to 30% of the volume of water used for snowmaking [7, 8]. 

Ratio of slopes with artificial snow cover [%] 70... 

Another whipped foam is ureum formaldehyde foam. A watery solution of ureum, formaldehyde and additives, is whipped to a very light foam. When this is dried at an elevated temperature, the resin is cured into a hard foam of a few kg/m3, to be applied in packaging and as artificial snow in shop-windows etc. 

LABORATORY STUDIES OF PHOTOCHEMICAL REACTIONS IN ARTIFICIAL SNOW... 

Table 1 Experimental photolysis rates in artificial snow for several investigated compounds. Rates were obtained for -20...

The reaction rate for the photolysis rate of H2O2 (R8) was calculated using data from previously published laboratory experiments of photolysis reactions of NOs and H2O2 in artificial snow for comparable experimental conditions (Table 1). Therefore, the obtained experimental rate constant of 0.48 h for the H2O2 photolysis was divided by a factor of 400 similar to the procedure for the photolysis rate of NOs as described in Jacobi et al. The HCHO photolysis reaction in snow is probably negligible under natural conditions and is not included in the reaction mechanism. 

The study of crystallization and alteration processes of natural and artificial snow crystals has been a subject of interest for several decades. Nakaya was the first who investigated the relations between growth forms and experimental conditions (temperature and water vapour saturation relative to ice). Although many laboratory" " and theoretical studies on ice crystals have been carried out since his seminal work, snow crystal growth is still not completely understood. Experimental studies are challenged by the complexity of the physical processes influencing the crystal growth, which are further complicated by effects of chemical impurities. ... 

Morioka, K. Nakahigashi, S. Construction plan of Tsudanuma skiing arenas with artificial snow and technology of making artificial snow. Refrigeration 1992, 67, 28 (written in Japanese). 

How come skiers say that artificial snow feels different from r ular snow ... 

Because artificial snow is different. It isn t really snow. Snowmaking machines actually manufacture tiny beads of ice, each about one-ten-thousandth of an inch in diameter. 

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