To better control energy consumption in its data centers, Microsoft has deployed 2,000 internally built temperature and humidity sensors in several of its facilities.

The sensors use ZigBee wireless technology to transmit the data to databases that analyze the information. Data-center administrators can look at a graphical image of the data center that is color-coded based on temperature and at a glance see areas that are getting hot.

Ultimately, Microsoft would like to be able to distribute computational load in the data centers based on the temperature of servers, and it is beginning to work on such a system, said Jie Liu, a Microsoft researcher working on the deployment. He showed off the devices and a view of the database at the annual Microsoft Research Faculty Summit in Redmond, Washington, on Tuesday.

For now, Microsoft is in part using the data it collects to test out information that vendors supply. "We can understand the operating conditions and compare them with the vendor specs," Liu said. Server vendors typically advise users to set operating conditions based on scenarios that essentially never happen during normal operation, such as 100 percent CPU use, he said. By testing out the real operating condition requirements for servers, Microsoft can potentially save money if it discovers, for example, that it doesn't need to keep the room quite so cool.

Microsoft is also working on using the temperature data it collects from the sensors to control fan speeds on the servers and to control the air-conditioning systems, he said.

The company has designed its own sensors. They use ZigBee, a short-range standard wireless technology that creates a mesh network to pass the data along. One of the shortcomings of ZigBee in this application is that it can handle only very small amounts of data, he said.

Sensors are placed at the front and the back of servers and at three rack intervals in Microsoft's deployment. Temperature doesn't change very fast in the data centers, so Microsoft experimented with how many sensors to use, keeping in mind the expense of the sensor. Liu could not estimate how much each sensor costs.

Microsoft has demonstrated its system to the Uptime Institute, an organization that offers information about data-center operations, Liu said. "There is lots of interest in this," he said. For now it's just a prototype that the company uses internally, and he couldn't comment on plans to commercialize the technology so that others could use it, he said.

Microsoft is in the process of building additional massive data centers to support what it hopes will be future demand for its online services. Data-center efficiency is a hot topic for companies like Microsoft that strive to operate the centers at the lowest cost possible in order to optimize revenues.