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May 2010

Next-Gen Snowmaking

Automating your snowmaking saves time, money and labor.

Written by Robin Smith, SnowConsult, Inc. | 0 comment

Among resorts that make snow, snowmaking is the biggest line item in the energy budget. Typically, 67 percent of all energy consumed by resort operations is used in snowmaking. In many other departments, resorts have already acted to cut costs. Snowmaking now represents the last great frontier for cost-cutting and efficiency gains.

Two scenarios drive a strategic snowmaking plan: opening objectives, and resurfacing objectives. With both of these, it is important that all stakeholders agree on what trails are “priority one” and how fastest to meet the objectives of opening or resurfacing them. This strategic plan allows you to control expenses and maximize capital.

That might seem obvious, but logic doesn’t always apply when it comes to snowmaking. One area with several top-to-bottom, ultra-efficient automated trails always opened a manual trail first—even though that required 30 percent more hours to get open top to bottom. Why make this decision? “We just want to get that manual trail out of the way,” they said. Also, the manual trail went by the cat garage, so the cat crews voted for access on snow. A simple strategic change to an automated trail has allowed the resort to open top to bottom a week earlier than in the past (and a week earlier than its competitors) every year for the past three seasons.

Good data on snowmaking operations is essential. However, even though snowmaking is one of the biggest budget line items—and one of the greatest influencers of visits and guest satisfaction—many areas are managing blind. Even when the data is readily available, they don’t use or learn from it.

Here’s an example. For five years, Aspen had an automated trail that tracked all sorts of data, but no one analyzed it. When it was eventually explored, the data showed Spar Gulch had 5.1 million gallons on it, laid down at a balmy 25.8 degrees wet bulb. When the trail crew and patrolmen were asked if that production was enough, it turned out it was probably more than enough. So the next year’s production goal was reduced.

This past year—using existing data to manage snowmaking by volume, plus adding automation to 10 existing fan guns, and using a snow inducer—yielded impressive results. In a very thin early snow year, Ajax pumped only three percent more water than the previous season, but increased snow volume by 22 percent, as measured by an A/B volumetric test. Aspen used 16 percent less kWh and lowered labor costs by 14 percent. All snowmaking objectives were completed in the shortest snowmaking season ever, even though temperatures were three percent higher than the previous three-year average. Energy and labor costs dropped 23 percent, from $1,077 to $831 per acre foot.

In another test, Aspen had two identical fan guns running several hundred feet apart. One was fully automatic, monitored from the control building out of sight and 1/2 mile away. The other was brand-new but had manual operation. At the end of one season of snowmaking, the automatic gun had flowed 30 percent more water. Other resorts that have monitored similar comparisons report even better results.

The lesson: automatic guns have a commanding performance advantage. For two reasons: they start automatically within minutes as temperatures drop through the 28 degree wet bulb barrier, and always go to the next bank and increase flow as temperatures continue to drop. In contrast, an eight-man crew tending perhaps 80 guns spread out over 900 acres will make those same adjustments “when they get there,” sometimes three hours behind the automated guns.

You can model the ROI all day long, taking into account the additional cost of automation vs. manual on that 30 percent gain, but that is only half the story. On the warming cycle of the curve, the auto gun is quickly turning off excess flow to keep snow quality constant. The unattended manual gun is flowing more, but making poor quality snow. At 28F wet bulb, the auto gun shuts off. The manual gun continues to pump out water—that doesn’t necessarily convert to snow—until manual crews shut it off.

In many cases, though, the crews decide to “run over the hump,” letting the gun run on minimum flow for hours, knowing that it will get cold again when the sun goes down. In a season-long test, we found that manual guns were run “over the hump,” above 26 wet bulb, 28 percent of the time. That is a lot of kWh conserved by automation when the computer determines it’s quitting time. See box below for an early-season analysis.

Here’s another case where automation helped. Wintergreen, Va., is 100 percent automated. In the first year the area doubled its seasonal pumping—not because they needed to, but because they could. Now, snowmaking manager Scott Gunnell uses the data from his snowmaking computer to build opening and recovery scenarios based on system data and the best weather forecasts he can get. He can track how many gallons are going to each gun on each trail. If he thinks the weather pattern is safe, he builds to the “no resistance” scenario, giving him maximum trail count in the shortest possible time and expense. If rain and thaws are coming, he builds to the “good resistance” level. He does this with three guys per shift, including him. As a result, Wintergreen makes only as much snow as it needs, and it makes that snow when the temperatures are favorable. You can see the differences in the chart on page 45.

Lots of people have connected meters to snowguns to see how much water a gun is flowing. It’s also easy to figure out how much energy the gun is using, whether it is an a/w stick or fan.

But if that is all you test, you are not getting the full picture. How many gallons of throughput does a gun need to produce an acre-foot of snow? You need to measure the volume of snow in front of the gun to know whether you have a truly efficient gun. That’s done most commonly with a stake and grid test.

Holiday Valley, N.Y., has been doing these tests and found that today’s multiflow guns, with discrete, sophisticated nucleation systems, whether sticks or fans, are much better converters of water into real snow volume than the guns of 15 years ago.

We have found this to be true not just in cold temperatures, but in marginal temperatures as well. Using the same stake and grid test, Holiday’s crew found that it was using approximately 155,000 gallons of water to make an acre-foot of snow. That’s the best I’ve ever seen, and that number didn’t vary much whether the test temperature was zero or 22F wet bulb. Holiday’s test area included several different makes and models of multiflow, low energy a/w tower guns and use of a snow inducer additive. Deer Valley and Aspen have achieved similar results using late-model fan guns.

By comparison, 30 tests done with 15-year-old equipment resulted in an average of 300,000 gallons to make an acre foot of snow. The newer guns are better nucleators, so there is less evaporation. A lot less. Also, more droplets exit as frozen crystals, increasing volume. This means there is less water leaching through the pack or compromising quality.

In short: the efficiency of the newer equipment has created a staggering improvement that has perhaps gone unnoticed. There are still many poorly-converting snowguns in use out there, squandering water and energy.

The ROI on technology is not simple to measure, but it can be done.

If you are replacing a resort full of first-generation a/w guns, or almost any technology more than 15 years old, with either auto fans or sticks, the ROI can be less than seven years on the energy and labor savings alone. If you can deliver increased market share, improved margin, and fill more beds in periods that can be influenced by trail count and snow surfaces, the return is faster. Wintergreen Resort is the best example of this (see “Put It on Autopilot,” SAM July 2007).

Many resort operators don’t like to consider the topline contribution of Blitzkrieg snowmaking in building an ROI. One western operator told me, “I don’t know what we make by having top-to-bottom skiing for Thanksgiving, but I can pretty much tell you what it will cost us if we don’t.”

If you are going to make the move to automation trail by trail, the return will come fastest from those “must have” priority-one trails, pipes and parks, where run hours are higher. Less temperature-efficient technology should be re-deployed on the priority-three trails, i.e., trails that can wait for sustained colder weather.

Pipes and parks can be a brand builder, but they also use 25 percent to 35 percent of all snowmaking resources.
Here are some common-sense steps that will save energy, water, and time:

• Work with your builders before snowmaking starts. Exactly where do they want their 30 million gallons? Trail groomers and park builders have very different needs for snow placement.

• What water content do they want? For fixed tower guns to remain efficient, intermediate snow harvests will be required. Agree how often, and try to do it when temperatures are down for snowmaking.

• Pre-shaping features with dirt can save huge amounts of time and energy.

Snowmaking represents the biggest opportunity remaining in resort operations to dramatically reduce cost, open terrain faster and recover it quicker. It helps to build the pipes and parks that appeal to our core sliders faster, without compromise, and without breaking the bank. We need to embrace proven technology, gather all the data we can, and use it to manage snowmaking with a new level of professionalism.

Robin Smith, president of SnowConsult LLC, does snowmaking operational analysis and consulting for resorts. Contact him at (303) 842-2495,

We asked suppliers for their latest and greatest developments. Here’s what they told us:

Areco/Snownet: Areco Snowsystem fan guns employ PLC-based automation and software that records operating statistics for up-to-date production information. Remote control or independent full automation with valve and pressure control provide a linear flow curve to maximize water flow for every degree of temperature change while maintaining a preset snow quality. Areco air/water lances using 25 cfm, manual or automatic, suit areas where power or space limit the use of fans.

HKD: HKD snowmakers’ seven air/water models employ a range of internal and external mix nucleation, as well as multi- and non-valve technology and on-board compressor-driven products, to offer a full range of energy efficient technology and price points. The SV10 Impulse is the newest example; its Air Control Technology allows it to operate in high temperatures. In addition, the Impulse can cut its air consumption to 25 CFM or less as water flow is increased in colder temperatures. Finally, the new HKD Automatic Hydrant makes automation more affordable; it debuts at the NSAA convention in Orlando in May 2010.

IDE Technologies: IDE’s All Weather Snowmaker produces up to 56,500 cubic feet of snow per day (just under half an acre-foot of snow) at any temperature. IDE’s Vacuum Ice Maker (VIM) technology churns out corn or spring-like snow. It’s an environmentally sound, energy-efficient system; energy use is roughly .17 kW per cubic foot, as long as the water is 41º F or lower; chilling warmer water doubles the cost. The technology has been used for more than 20 years in other applications, with the first two wintersports installations at Piztal glacier in Austria and Zermatt, Switzerland.

Johnson Controls Snow: For maximum efficiency, the Safyr snow gun has a motorized, variable size nozzle that changes flow based on weather conditions. The new Rubis EVO is a low-e, high-temperature gun that pushes the upper limit of temperatures. The new YB valve includes a separate line for the air hose so that the air line can drain in addition to the water line; supercapacitors in the valve allow for fail-safe operation in case of power loss, and the valve operates on a safer 24 volts (compared to the typical 460 volts for most valves). The latest Liberty automation software can tie it all together.

Larchmont Engineering: The new Z-1 guns have a reconfigured nozzle that makes them 24 percent more efficient—they use the same amount of air as in the past, but convert more water to snow. A new 10-foot Z-1 tower gun, developed in consultation with Okemo, can rotate 360 degrees.

Lenko Snow: The low-e Orion sticks offer production in marginal temps using hill air via an onboard compressor. The new machined-aluminum waterbox is coupled to a heated 2-inch valve to flush particulates and maximize production. All new production machines are equipped with oil-free compressors. Lenko fan guns can be retrofitted with larger orifice nozzles.

Ratnik Industries: It’s a busy year for this venerable snowmaker. Ratnik’s new three-step low-e Sky Giant VI addresses many of the shortcomings of current-generation low-e guns. More broadly, the redesigned Snow Giant air-water guns use less compressed air; older guns can be factory rebuilt with the new design. An automatic on/off gun system for fixed-flow snow guns, and a wireless, battery-operated line of weather stations, are also coming to market. A new line of small-capacity air/water guns—for ski tunnels, laboratories, and play areas, etc.—is also available.

Rogers Hydrants: Rogers’ flow controller allows snowmakers to dial in the flow accurately, which is especially important with stick guns. R&D focuses on constantly improving quality and reliability and to adapting to resorts’ changing needs.

SMI Snowmakers: SMI offers snowmaking master planning services for entire resorts, pods, and specific areas like trails, terrain parks, race courses or halfpipe areas. Understanding an existing system, creating snowmaking data bases, knowing how to analyze and create plans based on this data, and creating a bridge to new solutions requires some unique skill sets that SMI possesses. SMI’s approaches to trail automation—from simple on/off guns to advanced-intelligence, radio-controlled fan snowtowers such as Super Polecats—provide flexibility in crafting resort-specific solutions.

TechnoAlpin: New energy-efficient fan blades allow for increased throw and reduced noise, and heated blades (optional) are useful in high humidity applications. Guns can be controlled remotely from up to 300 feet away via Bluetooth technology. In lances, heat transfer technology in the head prevents freezing in blowback conditions. For versatility, the 12-foot, sled-mounted, manual high-performance MTS lance has four-step flow regulation and low weight. And a new client server version of TechnoAlpin’s automation software enables total snowmaking plant integration.

TopGun Snowmaking Systems: For efficiency, the TopGun nine-stage gun has nine water settings to maximize water flow at all temperatures. At the same time, TopGun has reduced airflow to 30 cfm without sacrificing marginal temperature performance or cold temperature maximum flow. The fixed-flow Pipedream has an efficient airflow of 45 cfm or 65 cfm.

Turbocristal: Turbocristal has achieved cost savings with a mix of SuperCrystal fan and LP air/water tower-type snowguns. Energy efficiency studies based on resort weather data help determine the best mix. With LP guns, resorts can reduce air pressure as ambient wet bulb temperatures drop. Resorts can control pressure to entire trails by a single valve, saving labor and time. Using the newest design of single-flow, low-e snowguns, resorts can maximize production in marginal temperatures and reduce capital investment.

-The Editors