- Nostromo Energy uses "ice batteries" to shift cooling power demand to off-peak times
- The technology, which uses frozen water for coolant, helps data center operators save energy, reduce costs and connect more quickly to power grids
- Nostromo previously provided its IceBricks to commercial buildings, including the Beverly Hilton and adjacent Waldorf Astoria hotels in Los Angeles
"Ice batteries" isn't just a fantastic phrase — it's emerging technology for cooling commercial buildings, such as offices, hospitals and hotels. And now, one startup is pitching ice batteries as a solution to cool data centers.
The principle is simple: Use electricity during off-peak hours to cool water into ice. During peak hours, use the resulting ice to cool water that is circulated through buildings, such as data centers.
"We store cold energy, create it when there is a surplus of power and discharge it when there is a shortage of power," Yoram Ashery, CEO of Nostromo Energy, told Fierce Network. Nostromo is one of several companies pioneering this innovative cooling technology.
In late November, Nostromo launched the IceBrick 360, "a patented cold-thermal energy storage (CTES) system engineered specifically for high demand data centers," the company said in a statement.
Its ice batteries are charged using a chiller, which is a compressor used to cool water below freezing temperature. The subfreezing but still liquid water is used to chill blocks of ice in well-insulated storage cells. That ice can sit for hours or days until needed, at which point the ice is used to lower the temperature of water that's circulated throughout the building.
"The ice is your battery, you charge it by freezing, discharge it by melting," Ashery said.
Watch this video for a visual explanation:
Bringing data centers online faster
A 10 megawatt data center would need about 13,000 ton hours to cool. A ton-hour is a unit used to measure the output of cooling systems. That scale of cooling using IceBricks requires 10,000-15,000 square feet of space, which can be positioned next to the building or laid flat on the roof, similar to solar panels. The new IceBrick 360 has a capacity of 360 ton hours, meaning 36 units would be needed for a 10 MW facility.
For data centers, 20-40% of energy is used just for cooling. Because energy is expensive, reducing energy requirements can result in significant cost savings. Moreover, reducing energy requirements can help bring data centers online faster, as data center construction is driving up demand for energy beyond current electrical utilities' capacity. This is leading utilities and grid operators to prioritize connections to "flexible large load" facilities "that can reliably commit to curtailment at times of peak demand," the company said.
Saving energy and shaving time to connection can be a significant advantage for data center operators as commercial electricity rates have risen nearly 30% since 2020, and the average wait time for a grid connection across the U.S. is now four years, according to JLL, a commercial real estate and investment management company.
And ice batteries improve resilience, as they can keep data centers cool for several hours, Ashrey said.
Nostromo received a conditional commitment for a loan guarantee of up to $305.5 million from the U.S. Department of Energy to deploy IceBricks at up to 193 commercial buildings and facilities across California, including a significant number of data centers, Ashery said. That commitment came in December 2024, under the prior Presidential administration, which had a drastically different energy policy compared with the current White House. But Ashery expressed optimism that the loan would come through, due to distributed storage's contribution to grid resilience and affordability.
Customers in the pipeline
Nostromo has already signed one data center customer, with several more in discussion, Ashery said.
Nostromo isn't the only company making ice batteries. Ice Energy deploys these types of thermal energy storage systems for homes, while Trane Technologies features universities as marquee customers.
Technology such as Nostromo's IceBricks could find high demand as the cost of energy to run data centers spikes and sustainability requirements become more of a priority, said analyst Sid Nag, Tekonyx president and chief research officer.
Data center operators are turning to a variety of established and emerging technologies to generate electricity and store power to shift demand to off-peak hours. These include solar; small modular nuclear reactors (SMRs); lithium-ion batteries; sensible heat, in which energy is stored in the form of heat in materials such as water, rock and sand; phase change, which stores energy in the change from solid to liquid or liquid to gas; and even molten salt — though many of these technologies are still unproven, Nag said.
"We never heard of the cost of cooling with traditional data centers. With the deployment of GPUs, which are massive heat-generating beasts, there is a massive focus in this area," Nag said.
He added, "With these GPU clusters, it gets so hot it feels like a sauna inside."
However, as the industry develops alternatives to GPU architectures, we will see cooling addressed inherently in the silicon itself, which might make ice batteries and other cooling technologies irrelevant, Nag said.
About the company name
We asked Ashery about the company name, Nostromo. He said most people think it comes from the movie "Alien," but it actually comes from the novel of that title by Joseph Conrad, which Yaron Ben Nun, company founder, president and CTO, is a fan of.
Nostromo is the nickname of an important character in that novel; the word comes from the Italian "nostro uomo," meaning "our man," signifying that Nostromo is extremely trustworthy.