A California newcomer to the data center cooling arena has directly targeted none other than the established cooling systems manufacturer that reportedly dominates 70 percent of the market: Emerson Network Power’s Liebert Corporation.

Core4, a Napa-based start-up, announced that the first data center to deploy its system cut its cooling costs by 72 percent. Dane Jasper, CEO of Sonic.net – owner of the said data center in Santa Rosa, Calif. – stands by the figure.

Core4 says kW Engineering audited the figure and utility PG&E verified it.

Liebert was the incumbent cooling equipment supplier to the data center and its units were replaced with Core4 kit as part of a major overhaul. It is not clear exactly which Liebert CRAC systems were replaced, their age or performance and no details were given of the proposed Liebert solution which lost out on the project.

Liebert declined to coment on the announcement when approached by DatacenterDynamics and a representative of APC – another major player in the market – said their team could not find enough information on the new system to make a statement.

A case study Core4 provided for DatacenterDynamics compares the amount of power its system at Sonic.net requires per 100 tons of cooling to the amount of power a Liebert CRAC installation requires to cool the same. The former uses about 1,318,000 KWH less per 100 tons of cooling than does the latter according the supplied information.

Replacing three Liebert airhandlers with the Core4 installation caused Sonic.net’s monthly energy bill to shrink by $10,000-$12,000 per month, depending on the weather, Jasper said.

As demand for its services grew, Sonic.net decided it needed to increase the data center’s cooling capacity. A vendor bid to install two more Liebert airhandlers was priced at $250,000 said Core4 which itself offered to replace the entire system for more than $600,000.

“We could’ve brought (in) two more Lieberts,” Jasper said. “That would be the more conventional decision to make.”

According to the case study the increased energy efficiency saw utility PG&E issue Sonic.net with a $153,000 rebate for increasing energy efficiency.

The retrofit process took about half a year and Core4 was able to run its system in parallel with existing Liebert air handlers, without any major disruption of the data center’s core functions.

The supplier said the biggest power reduction is driven by Core4’s patent-pending Reduced Compression design methodology which resulted in 44 percent of total savings.

It “allows for the unlimited reduction of the condensing temperature and a limited increase in the evaporating temperature to achieve a reduction in compressor KW’s and an increase in the compressor capacity,” according to a Core4 document. “…as the condensing temperature goes down, the power needed to turn the compressor goes down as well. At the same time, the capacity of the compressor goes up. The net result on the compressor is more work for less energy.”

In addition the system runs with compression levels that are much lower than normal.

Core4 VP of Product Development Jamien McCullum said: “We’re using compression levels within our system that are much much lower than a manufacturer would even consider.”

In the aforementioned case study Core4 wrote that while most compressor manufacturers do not “openly” design for a reduced compression system design of this magnitude, “Our system design and components have been selected for these parameters and the manufacturers have approved of our application of their components within the Core 4 overall design.”

Another major contributor to efficiency is the fan system. The large axial fans are mounted at an angle, blow directly under the raised floor and provide 15,000 CFM per 2.2 KW.


Core4's Sonicnet data center cooling set up is being cited as a direct challenge to established players

After compression and the fans, the system’s refrigerant-side economizing is the third largest factor in its energy efficiency. “We get about 6,000 hours a year of economizing,” McCullum said.

The savings are achieved by using very large and thick flat indoor coils. A coil’s large area allows it to remove heat at a higher outdoor temperature, “which translates into more hours of economizing,” according to the Core4 document.

Warmer fluid temperature in itself also leads to an increase in efficiency.

“Larger fluid temperature difference on the economizing and main portion of the coil allow for a greatly increased portion of heat removal without compressor energy in the form of either water-side economizing or refrigeration-side economizing. Lower pump energy due to reduced flow rates and increased BTU removal. As the temperature difference in the fluid increases the flow rate decreases.”

A patend is pending on Core4’s economizing technology as well.

Sonic.net’s Santa Rosa facility has about 5,000 square feet of data center space and another 5,000 square feet of empty warehouse space for further expansion, Jasper said. Most of the utilized space is used for colocation services.