Snowmaking with a snowfactory

Wednesday, 18 October 2017 - Written by admin

Snowmaking is the production of snow by forcing water and pressurized air through a “snow gun,” also known as a “snow cannon”, on ski slopes. Snowmaking is mainly used at ski resorts to supplement natural snow. This allows ski resorts to improve the reliability of their snow cover and to extend their ski seasons from late autumn to early spring. Indoor ski slopes often use snowmaking. They can generally do so year-round as they have a climate-controlled environment.

The production of snow requires low temperatures. The threshold temperature for snowmaking increases as humidity decreases. Wet bulb temperature is used as a metric since it takes air temperature and relative humidity into account. Snowmaking is a relatively expensive process in its energy use, thereby limiting its use.

The key considerations in snow production are increasing water and energy efficiency and increasing the environmental window in which snow can be made.

Snowmaking plants require water pumps and sometimes air compressors when using lances, that are both very large and expensive. The energy required to make artificial snow is about 0.6 – 0.7 kWh/m³ for lances and 1 – 2 kWh/m³ for fan guns. The density of artificial snow is between 400 and 500 kg/m³ and the water consumption for producing snow is roughly equal to that number.

Snowmaking begins with a water supply such as a river or reservoir. Water is pushed up a pipeline on the mountain using very large electric pumps in a pump house. This water is distributed through an intricate series of valves and pipes to any trails that require snowmaking. Many resorts also add a nucleating agent to ensure that as much water as possible freezes and turns into snow. These products are organic or inorganic materials that facilitate the water molecules to form the proper shape to freeze into ice crystals. The products are non-toxic and biodegradable.

Pump House & Air Plant Combo
The next step in the snowmaking process is to add air using an air plant. This plant is often a building which contains electric or diesel industrial air compressors the size of a van or truck. However, in some instances air compression is provided using diesel-powered, portable trailer-mounted compressors which can be added to the system. Many fan-type snow guns have on-board electric air compressors, which allows for cheaper, and more compact operation. A ski area may have the required high-output water pumps, but not an air pump. Onboard compressors are cheaper and easier than having a dedicated pumping house. The air is generally cooled and excess moisture is removed before it is sent out of the plant. Some systems even cool the water before it enters the system. This improves the snowmaking process as the less heat in the air and water, the less heat must be dissipated to the atmosphere to freeze the water. From this plant the air travels up a separate pipeline following the same path as the water pipeline.

Ice nucleation-active proteins (Snomax)
The water is sometimes mixed with ina (ice nucleation-active) proteins from the bacterium Pseudomonas syringae. These proteins serve as effective nuclei to initiate the formation of ice crystals at relatively high temperatures, so that the droplets will turn into ice before falling to the ground. The bacterium itself uses these ina proteins in order to injure plants.

The pipes following the trails are equipped with shelters containing hydrants, electrical power and, optionally, communication lines mounted. Whereas shelters for fan guns require only water, power and maybe communication, lance-shelters usually need air hydrants as well. Hybrid shelters allow maximum flexibility to connect each snow machine type as they have all supplies available. The typical distance for lance shelters is 100–150 feet (30–46 m), for fan guns 250–300 feet (76–91 m). From these hydrants  1 1⁄2″–2″ pressure resistant hoses are connected similar to fire hoses with camlocks to the snow machine.

Home snowmaking
Smaller versions of the snow machines found at ski resorts exist, scaled down to run off household size air and water supplies. Home snowmakers receive their water supply either from a garden hose or from a pressure washer, which makes more snow per hour. Plans also exist for do-it-yourself snowmaking machines made out of plumbing fittings and special nozzles.

Volumes of snow output by home snowmakers depend on the air/water mixture, temperature, wind variations, pumping capacity, water supply, air supply, and other factors. Using a household spray bottle will not work unless temperatures are well below the freezing point of water.

Source: Wikipedia