- A new study has found a novel way to turn data center waste heat into new power
- The technique outlined can generate power equivalent to 5% of a facility's total capacity
- The study's authors are hoping to put their modeling into action via a real-world pilot
Researchers from Rice University have found the key to putting data center waste heat to work for new power generation. And their approach to heat recovery couldn’t have come at a better time.
In a freshly published study, Rice’s McMurtry Chair in Mechanical Engineering Laura Schaefer and graduate student Kashif Liaqat modeled how solar collectors can be used to increase the temperature of data center waste heat such that it can, in turn, be used by an organic Rankine cycle (ORC) system to produce electricity. ORCs work by converting a working liquid into a gas to turn a power-generating turbine.
The study’s result? A solution capable of using data center waste heat to generate power equivalent to 5% of a data center’s total capacity. In other words, a 1 gigawatt data center could use this heat recovery technique to generate 50 megawatts of behind-the-meter power.
Given the power constraints facing data centers in many regions across the globe, the approach seems like it could be a much-needed windfall for the industry. But it notably uses well-established and time-tested components like the ORC. So, why hasn’t it been done before?
“Until recently, this hasn’t been feasible for the standard industry five-year payback period,” Schaefer told Fierce. “But as the electricity costs have gone up, all of a sudden this becomes a lot more economically viable. It’s nice when industry is driven by environmental and social concerns, but it’s almost always the economic concerns that drive the bus.”
Turning lemons into lemonade
To be clear, efforts to put the heat data centers generate to work aren’t new.
For instance, waste heat from data centers is already used to warm buildings, pools and even greenhouses in Sweden, Finland and Canada. Microsoft, meanwhile, recently disclosed its efforts to use waste heat to power its direct air capture (DAC) systems which help remove carbon dioxide from the atmosphere.
But using waste heat for data center power generation is still a nascent use case.
Why? Data center waste heat is usually cooler than the threshold required to efficiently run an ORC system. That could, of course, be corrected by electric heat pumps, but doing so would just increase the data center’s power consumption.
Schaefer and Liaqat, though, had the novel idea to use the sun to boost the temperature of data center waste heat. This can be done using solar collectors, which utilize a dark absorbent surface to collect energy from the Sun and transfer that to air or liquid. And data centers have plenty of roof space to accommodate these.
The study modeled what it would look like to apply a solar-boosted ORC heat recovery system to data centers in Ashburn, Virginia and Los Angeles, California. While the system performed better in Los Angeles – because, of course, more sun equals more heat – the pair found a significant potential for waste heat recovery in both locations.
Liaqat told Fierce that adding thermal storage – not to be confused with battery storage – could enable more consistent power generation from the ORC system during the overnight hours when the sun isn’t shining anymore.
Next steps
The study was mostly a modeling exercise, but Schaefer and Liaqat said they’re hopeful an actual pilot will follow. Following the report’s publication, Schaefer noted that data center operators reached out to the university, and Rice is also actively trying to make connections to facilitate a physical installation at an operational facility.
But Schaefer also said that given the commonality of the ORC system and fluid used (R601, for refrigerant nerds) for its modeling, data center operators could also take a stab at deploying this on their own.
“The big message is higher costs are coming and the earlier you get on board with adopting these technologies, the further ahead you’ll be,” Schaefer said.
This story has been updated with a corrected version of Schaefer's title.