BOSTON--Many green-tech start-ups are formed with the hopes of bringing a scientific discovery from a university lab to market. Digital Lumens has taken a different tack: it's applying well-known computer technology to dramatically boost efficiency in lighting.

On Friday, I visited Digital Lumens' office here to get a closer look at its commercial LED light fixture, a rectangular-shaped spot light roughly the size of a desktop computer. On one side are three light bars blasting out light, on the other is the computing "horsepower" that allows it to be controlled like other equipment on a company network.

Three-year-old Digital Lumens, which raised a $10 million series B round in venture funding last week, is one of many companies applying existing technology to the energy field for better efficiency or productivity, such as car-sharing sites or solar monitoring applications. Some see the cross between IT and energy as a ripe field which generally better fits the venture investing model compared to solar, battery, or biofuel technologies.

In Digital Lumens' case, it's going after a very narrow market, at least at first. It has several dozen customers which use its Intelligent Light Engine product for lighting up warehouse aisles and now with additional funding, it's eyeing new industries to move into.

By replacing the typical high-intensity discharge lamp or fluorescent lights used in commercial spaces, it can knock down the power consumption significantly simply because LED lights are more energy efficient. One of its fixtures using 160 watts can replace a 400-watt lamp and give off as much or more light.

But adding an embedded processor and Zigbee wireless mesh networking chip turns lights into a "managed resource" and makes the investment in LED lighting more compelling, according to Digital Lumens chief technology officer Brian Chemel. Schools or municipal organizations may consider a four- or five-year payback for an efficiency investment but that's not the case across the board in industry, he said.

"If the payback is more than two years, don't even bother going in," said Chemel. "This is very driven by payback and after two years, it drops straight to the bottom line."

The on-board processor allows the fixture to collect and process data, giving facility managers fine-tune control over lighting, Chemel said. People can make better use of occupancy sensors, which often don't work well, and set a lighting schedule by aisle or by room, he said. LEDs can be dimmed and their life doesn't degrade by turning them on and off often, as it the case with fluorescents. Using the accompanying Web-based software application, people can adjust settings and track the financial results of switching to LEDs.

The energy savings from some of its early customers have been dramatic, with one customer reporting a 90 percent reduction in lighting load. Although Digital Lumens is targeting a narrow audience, businesses are big electricity consumers. One customer's energy reduction would be the same as the entire town doing a deep energy efficiency retrofit on all residential buildings, Chemel said.

Toehold for smart buildings Digital Lumens' fixtures right now collect and process data about light levels and motion in aisles, but the system could collect a wider array of data. For example, sensors to track temperature or air quality could be added, opening up different uses, such as hospitals, Chemel said. Another possibility is connecting security cameras to track traffic in retail outlets.

There are several companies, including IBM and Cisco, developing technology to improve commercial building's energy efficiency by collecting and analyzing data from building management systems. Chemel sees lighting as a way to bring intelligence into buildings without the complexity and expense of building-wide systems.

"We see the lighting network as the scaffolding that building automation systems will be hung," he said. "The applications are very broad and lighting is so pervasive. The ability to harness those systems is pretty disruptive."

While many green-tech start-ups highlight the environmentally friendly attributes of their products, the primary focus at Digital Lumens is on economics, with environmental benefits a secondary consideration.

Chemel and a few other Digital Lumens employees came from Color Kinetics, an LED company specialized in decorative lighting where they did 15,000 installations that always added more lighting load to the electric grid. Now this new company, which employs both lighting and networking industry veterans, is lightening the environmental footprint of lighting on the grid. "We can push out a very efficient technology where it makes economic sense but we're also doing a good thing," Chemel said.