When ski areas look to reduce energy costs, the first natural place to look is snowmaking, the great consumer of operation budgets. And in snowmaking, the places to look are pumps and air compression—the latter can gobble up a whopping 50 percent of snowmaking costs. It ain’t cheap to turn air into a useful force, but it is getting more efficient.

Thanks to new trends and technologies in the pump and air compression category, resorts across the country are covering more acres with less energy and doing so with the help and blessing of their local utilities.

One key technology: variable frequency drives (VFD, also called variable speed drives), which have become popular as an affordable power-saving solution for fans, pumps, chillers and HVAC systems in large facilities. VFDs have been adopted into snowmaking systems for the same reasons and are encouraged with incentives by most utility companies (although this varies state to state).

Variable frequency drives are controllers that vary the speed of induction motors. They help facilities save energy because they adjust to the load required, instead of running at peak capacity all of the time. “VFDs save substantial energy when applied to variable-torque loads, thus reducing electricity bills for most facilities,” the U.S. Department of Energy says in its guide to energy-efficient retrofits. “These energy savings are possible with variable-torque loads, such as fans and pumps, because torque varies as the square of speed, and horse-power varies as the cube of speed. For example, if fan speed is reduced by 20 percent, motor horsepower (and energy consumption) is reduced by 50 percent.”

In snowmaking applications specifically, VFDs are especially valuable because they allow pumps to maintain a constant pressure despite the varying load and demands on the system. If you set the system pressure to 500 pounds, the pump will speed up or slow down to maintain that constant pressure. The result is more consistent snow quality and less energy used to create it.

In the unpredictable and changeable conditions of the East, where snowmaking can make or break a season, Bristol Mountain, N.Y., has become well known for its stand-out snowmaking system. Head snowmaker Ken Keenan, a 30-year veteran of the industry (“I still run the 18-year-olds into the ground,” he laughs), has worked with the resort to invest over $1.2 million into Bristol’s snowmaking system in the last five years to create a system that’s innovative and effective for the resort’s bottom line.

In addition to larger air- and water-pipe sizing to accommodate for friction losses and more efficient performance, Keenan has also installed VFDs on his trim pumps. Although he says it’s tough to separate the impact of the VFDs from all the other improvements Bristol has made in its system, it has definitely made an impact on efficiency.

“There’s definitely savings there,” he says. “Generally, when we make snow we’ll pretty much go full out. Our variable frequency pumps are our trim pumps, so they’re capable of about 1,000 gallons a minute with 500 horsepower, and [with the VFDs] we might only be using 500 or 600 gallons on that pump. So it can save anywhere from 10 or 20 percent to 60 or 70 percent. It’s significant.”

Keenan says the resort worked with its local utility to take advantage of the incentives associated with the installation of the VFDs. They are definitely a “good energy saver,” Keenan says, and with all of the other upgrades to the system, including an automated control system he helped design, the resort is able to cover much more ground with an equal amount of manpower—a move that makes everyone happy.


OTHER TRENDS

There are other major trends in pump and compressor technology that are helping to cut costs, says Ron Ratnik, president of snowmaking equipment manufacturer Ratnik Industries. The first is boosting the system’s operating water pressure, which increases snowgun efficiency and capacity.

Another major trend in pumps, he notes, is to increase pumping capacity by replacing smaller-capacity pumps with higher-volume pumps. This is a popular move because it can be done without expensive on-site construction. For example, he says, if you replace a 150-horsepower pump with a 300-horsepower pump that is roughly the same size, you can effectively double the capacity of the system without incurring the costs of reconstruction.

The trend in air compressor technology simply is to be more efficient. The number-one way this is being achieved, says Ratnik, is to replace rotary screw air compressors with three-stage centrifugal compressors. The energy savings from such a move are usually between 20 and 30 percent, he says, and it’s the kind of investment energy utilities are often willing to offer incentives toward.

This upgrade has become feasible for more resorts because of the relatively recent availability of smaller centrifugal compressors. Previously, this technology was limited to larger resorts with a need for a 400-horsepower compressor. “Now smaller areas can have centrifugal compressors just like big areas,” he explains. “There’s a fair amount of energy to be saved there.”

Other compressor trends include the replacement of cooling and inter-cooling systems with closed-loop water glycol systems or air-cooled systems, an upgrade that not only saves water, but also reduces the amount of hot water being discharged back into reservoirs. Similarly, more efficient moisture and oil separation is available, so whether a resort has rotary or screw compression, says Ratnik, it can reduce the amount of contaminants going into the environment.


GO GREEN FOR THE GLORY (OR THE ROI)

The move toward more energy efficient pump and compressor systems, in addition to more environmentally-friendly technologies, is a welcome one in a world that is increasingly green-crazy. This creates marketing opportunities as well as cost savings. Prestigious awards for environmental stewardship, like the NSAA’s Golden and Silver Eagle Awards, and boast-worthy standards, such as ISO 14001, help resorts differentiate themselves in the marketplace and perhaps even attract ecologically-minded visitors.

Cost, however, remains a primary motivation for upgrading a snowmaking system, and the investment must deliver a reasonable rate of return. Ratnik says an ROI of five to 10 years is “realistic” for investments such as the ones listed above, especially when you factor in other upgrades that allow resorts to make more snow in less time (or in off-peak hours, which utilities will often give incentives toward), saving on labor and equipment run times. Finally, the length of ROI is rendered less important by the fact that pumps and compressors tend to last for a long time. They need to be maintained, of course, but they are less often replaced.

While guns tend to steal most of the glory in the world of snowmaking advances, it pays to pay attention to pumps and compressors. They, too, can generate significant savings with respectable return on investment—and that is what smart energy efficiency retrofits are all about.