Data centers might only account for 1.5 percent of the electricity consumed in the U.S., but they remain one of the more active areas for venture investors and startups.

Case in point: SynapSense, which provides equipment and services for curbing data center power consumption, announced it has pulled in $7 million more in funds. The round included earlier investors like Nth Power and American River Ventures as well as a new face: Robert Bosch Venture Capital, the venture arm of the decades-old German engineering firm.

SynapSense essentially measures the pressure, temperature, humidity and other environmental factors inside a data center and then makes recommendations on how to redesign it to curb power. Close to half of the energy consumed by data centers goes into the air conditioners, which effectively are trying to get rid of waste heat that itself is really just energy that's delivered (but not consumed) by servers, storage devices and other computers. Hence, up to 80 percent of the power consumed by data centers is not used in a productive manner, according to Donnie Foster, CEO of Power Assure, which makes software for controlling data center power consumption.

The potential for energy conservation, along with the growing demand for data centers, are two of the primary factors driving the cool data center market, but there's more. Technology companies are some of the most aggressive when it comes to latching onto new trends. When power prices began to climb, Intel, Sun Microsystems, IBM, startups like SynapSense and others all quickly found ways to show how curbing energy meant saving money.

Many of these data center-centric companies also want to ultimately take these skills into building and facilities management: Cisco has stated that it will go after buildings with its EnergyWise platform after it conquers telecom equipment.

Some of the ideas growing in popularity for data centers: use cool ambient air instead of air conditioning. The fans, filters and other systems required to pull in outside air consume far less power than air conditioners. Microsoft plans to use outside air in its mega-data center in Ireland. Others are promoting using DC, rather than AC, power to run data centers so less energy gets lost in the conversion.

Other companies in the efficient data center field include Sentilla, which raised $7.5 million earlier this year, and Power Assure, which has landed Facebook as a client (see Sentilla Raises $7.5M to Compete in Data Center Power Fray).

The Bosch participation also likely reflects another growing trend. Expect to see more strategic investors participate in the market as greentech moves from theory to implementation, said Peter Nieh at Lightspeed Venture Partners in a recent interview.