Of the many sources of emissions to tackle, waste heat recovery has a certain appeal. Every industrial plant produces more heat than it needs, and capturing that excess to cut costs and improve efficiency seems intuitive.
But Addison Stark, CEO of industrial heat pump manufacturer AtmosZero, thinks the pursuit of heat recovery is a distraction from more solvable challenges in industrial decarbonization.
“Waste heat is a waste of time, because people are chasing after a small increase in [coefficient of performance] to justify and minimize OpEx,” he said, speaking on the Catalyst podcast with Shayle Kann. “But what they’ve inadvertently done is essentially driven a massive increase in CapEx by trying to capture waste heat.”
A range of companies, like Siemens, Ormat, and Kawasaki Heavy Industries, offer waste heat recovery systems. And major industrial players like ArcelorMittal and Cemex have deployed projects into their facilities. Data centers are doing it too.
But Stark argues that waste heat recovery has struggled to scale for decades — and it won’t clear its hurdles any time soon. Stark and co-author Gregory Thiel, director of technology at Energy Impact Partners, detailed the sector’s challenges in a paper in the journal Joule.
Listen to Addison Stark’s whole interview on Catalyst:
One barrier is that every industrial facility is unique, and so every recovery project requires its own unique engineering. “Waste heat is not always located in the exact same place at the exact same temperature in every given facility,” Stark said. “So you’re building bespoke one-off heat exchangers with very expensive engineering hours.”
That makes it difficult for a company to replicate success across multiple sites, limiting cost reductions and deployment speed.
Another issue comes down to physics: waste heat is often expensive to capture efficiently.
“The lower the temperature it is, you need to have larger heat exchangers to be able to capture that and put it into the other working fluid that increases CapEx,” Stark said. “Essentially the total usable energy in there is much lower … so you have to do more work just to actually get something out of it — and there’s less to get out of it.”
Instead, Stark sees a better opportunity for decarbonization via industrial steam, which accounts for roughly 30% of industrial heat in the U.S.
AtmosZero, where Stark is CEO, manufactures modular industrial heat pumps to compete with the fossil fuel and resistive boilers that dominate steam production. Industrial heat pumps have been around for decades, but mostly remained niche, Stark explained, in part because of the focus on waste heat.
“You’ve got to get up to above 100 [degrees] Celsius to be able to deliver steam,” he said. “So how people have traditionally tried to do that is they’ve captured waste heat in the facility. They’ll go after and find some sort of a source from a unit operation on the manufacturing floor, capture that and then upgrade it.”
The work to capture and upgrade the heat has been a key challenge that stymied both waste heat recovery, and the technology of the heat pumps involved. AtmosZero’s approach skips waste heat entirely, marketing its modular boiler as a cheaper, drop-in solution that largely avoids the custom engineering.
“It has been tantalizing for 30 years,” he said. “It’s kept industrial heat pumps to be a very limited and one-off bespoke industry, and no one has really been able to scale.”
