Optimum Energy Wants Buildings to Use More Software, Waste Less Power

4/6/09

If you work in a commercial building, you’re probably familiar with the vagaries of large-scale heating and cooling systems. Hear that whir click on and cold air suddenly gusting through the vents? That’s the sound of your building hemorrhaging money and energy.

Seattle cleantech software company Optimum Energy wants to stanch the energy drain of the U.S. commercial sector, one building at a time—and soon, hundreds of buildings at a time—by slowing down the motors that power those buildings’ heating and cooling systems.

I traveled down to Optimum’s Georgetown office, which houses 22 of the three-year-old company’s 30 employees, to find out from founder and CEO Nathan Rothman how Optimum plans to save companies hundreds of thousands of dollars every year with a simple software program.

The company’s software products have the potential to halve the heating and cooling bills of about 110,000 large buildings in the U.S., Rothman said. That’s no small potatoes, when you consider that commercial buildings use 18 to 20 percent of the country’s energy, and that in hot climates like California or Texas, air conditioning accounts for more than half of their energy bill.

“If we implemented our technology just in Manhattan, we’d save enough electricity to light the other four boroughs all the time,” Rothman said. “And that doesn’t include the CO2 and greenhouse gases you’re saving.”

Large buildings maintain temperature control (or HVAC, for heating, ventilating, and air conditioning) using a massive network of cold water that courses through the building, absorbing heat and venting it through steam. That cold water is generally kept at a chilly 44 degrees Fahrenheit by a large machine aptly dubbed the “chiller.” High-powered motors and pumps drive the water around the building.

So what happens when a hot building cools down to, say, 70 degrees? The motors shut off, but then power back on the second it bumps up to 71—an incredibly inefficient process, Rothman said, as powering down and up uses a lot of energy.

That process starts to sound even more inefficient when you take into account a certain physical property of hydraulic pumps called an affinity law, where slowing the motors in the HVAC system by a certain amount results in triple that amount of energy saved. So if you reduce how hard the chiller runs from 100 percent to 70 percent of its full capacity—using a special piece of equipment that feeds electricity to the motors and other equipment in short bursts so as to run them at slower speeds—you’d only be using a third of the original energy, Rothman said. But nobody took this property into account in the days when modern HVAC systems were designed and energy was dirt cheap.

I asked Rothman if the current cooling method could be likened to a car trying to drive an average speed of 25 mph by driving 50 mph, then stopping, then going 50, then stopping. It’s even worse than that, he said.

“The way the current system works is, you put the gas pedal to the floor, and run that engine as fast as you can and just apply the brake when you want to slow down, never taking your foot off the gas,” Rothman said. “And we’re saying, wait a minute, forget the brake, and take your foot off the gas a little!”

Their software product, called OptimumLOOP, controls the HVAC systems on site (the systems are all controlled by computers that OptimumLOOP is installed on) to keep them running only at the capacity needed to keep buildings at comfortable temperatures, instead of at their maximum capacity. That maximum capacity is designed to meet the hottest day of the year, Rothman said, but the equipment is normally kept running at full capacity the other 364 days as well. The computers are connected to the Internet, allowing building owners and Optimum Energy to monitor the energy usage remotely.

And the price for these energy savings? Optimum’s services tend to range from $400,000 to $1 million for a large building, Rothman said, which includes the software and upgrades on the cooling equipment. That money is typically made back in one to three years through savings on energy bills and government rebates, he said.

Rothman, whose past positions included chief executive of Valiant Yacht and the manufacturing company Global Equipment & Technology, founded Optimum Energy with Jim Hanna in 2005, funding the startup himself. Optimum then raised capital from private groups.

With 55 buildings under its belt (including the San Jose and San Diego airports) and another 168 in the pipeline, the company has had some profitable months recently, Rothman said. He projects it will be a $75-$100 million company in five years.

But Rothman has bigger goals than the dollar. The company estimates that there are 110,000 buildings in the country that are eligible for its system—and that figure is big enough to have a strong impact on energy savings and the environment. “If our stuff was implemented across the United States, you wouldn’t have to build another power plant for ten years,” he said.

Rachel Tompa is a freelance journalist based in Seattle. She can be reached at rmtompa@yahoo.com. Follow @

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  • http://www.keepcomfy.com/ Utah heating

    a certain physical property of hydraulic pumps called an affinity law, where slowing the motors in the HVAC system by a certain amount results in triple that amount of energy saved. So if you reduce how hard the chiller runs from 100 percent to 70 percent of its full capacity—using a special piece of equipment that feeds electricity to the motors and other equipment in short bursts so as to run them at slower speeds—you’d only be using a third of the original energy, Rothman said. But nobody took this property into account in the days when modern HVAC systems were designed and energy was dirt cheap.