Sentilla has released an update to its data-center energy management tool, which lets IT and facilities staff track the energy usage of servers and other equipment. The latest version is a software-only product that adds a chargeback capability, allowing companies to bill individual business units for the energy they use.

Energy use in data centers has come under the spotlight for several reasons. More powerful and dense server equipment is pushing some facilities to the limits of their capacity, and higher energy costs and the threat of carbon legislation are making senior executives pay more attention to data center efficiency.

Sentilla released the first version of its Energy Manager for Data Centers early last year. The product helps IT and facilities staff to identify servers that are standing idle or using more energy than they should be, and can also issue alerts when capacity thresholds approach to reduce the risk of outages.

Energy Manager Version 3.0, released Tuesday, adds a reporting tool that can break down energy use by application or some other user-defined property, so that companies can charge business units for the energy they use, much as some are already doing for storage and server resources.

The idea is to make business units that never see their data-center energy bill accountable for the power they use. "Accountability makes people more conscious of savings," said Sentilla CEO Bob Davis.

The company had to rethink how it delivers the product. The first Energy Manager used small hardware devices that plugged into each piece of equipment and sent energy-use data back to a central console. Sometime last year, Sentilla decided that system was too complex and time-consuming to deploy in large data centers, and the new product is entirely software-based.

Once installed, the software maps out the hierarchy of an entire data-center electrical infrastructure, using protocols like SNMP and Modbus and tapping into building management systems. It then reads usage data supplied by the metered equipment, such as Universal Power Supplies and chillers, and calculates energy use for the remaining, unmetered equipment through a process of elimination, "a bit like doing a Sudoku puzzle," Davis said.

The technology, which Sentilla calls its Inference Engine, can be accurate to within 2 percent, according to Davis.

Another change is that Sentilla Energy Manager is now being marketed for wider use. It was originally pitched as a way to track energy use by servers and storage gear, but Sentilla now says it can be used to monitor power distribution and cooling equipment, which account for around half the energy consumed in many data centers.

Pricing for Sentilla Energy Manager 3.0 is based on the number of devices in a data center, "ultimately averaging $100 per device per year," the company said. Sentilla has three enterprise customers for the product, as well as 10 paid pilot tests under way, according to Davis.