Accelsius Names John Hewitt Chief Executive Officer; Founding CEO Josh Claman Becomes Executive Chairman
Former Vertiv executive will lead Accelsius in planned leadership transition to add data center scaling expertise as Accelsius moves from proving two-phase cooling to scaling it.
Founding CEO Josh Claman to focus on strategic partnerships and capital strategy.
Accelsius, the leader in two-phase, direct-to-chip liquid cooling for AI and high-performance computing, today announced that John Hewitt, a founding Accelsius board member and seasoned data center infrastructure executive, will be appointed Chief Executive Officer. Founding CEO Josh Claman, who has led the company since its inception, will assume the role of Executive Chairman, where he will focus on strategic partnerships, customer relationships and the company's capital strategy.
The appointment marks a planned evolution of leadership designed to support the company's rapid scaling. Accelsius has emerged as a leading force in commercializing two-phase liquid cooling for the AI era, with recent milestones including a $65 million Series B funding round led by Johnson Controls with strategic participation from Legrand, the general availability of its NeuCool® MR250 row-based Coolant Distribution Unit, the launch of the NeuCool IR150 integrated rack at NVIDIA GTC 2026, and customer deployments spanning hundreds of megawatts of new capacity.
Hewitt will join Accelsius from Robertshaw Controls, where he currently serves as Chief Executive Officer. He previously led Vertiv's $3.5 billion Americas business as President, where he sat at the center of the AI-driven data center build out, integrating acquisitions, rebuilding the go-to-market organization, and delivering profitable organic growth that significantly outpaced the market. His career also includes senior leadership roles at TE Connectivity, Motorola and Baker Hughes. He holds several board positions and has served on the Accelsius board since its founding, giving him a deep working knowledge of the company, its technology and its customers.
"Accelsius has built something rare: a category-defining technology platform with the team, the customers and the partnerships to scale it," said John Hewitt, incoming CEO of Accelsius. "Having a front row seat to the accomplishments in Austin, I know first-hand what Josh and the team have created. Two-phase, direct-to-chip cooling is expected to become the standard for the most demanding AI and HPC workloads, and Accelsius is exceptionally well positioned to lead that transition. My focus will be on operational scaling, accelerating our manufacturing capability, and deepening our relationships with the hyperscalers, OEMs and infrastructure partners who are building the AI factories of the future."
Under Claman's leadership, Accelsius built the scientific foundation, the team and the partnerships that established two-phase, direct-to-chip cooling as what is expected to become a de facto standard for cooling AI and HPC chips. In the four years since founding, Accelsius has developed an entire product line of two-phase DTC CDUs addressing a range of use cases in the data center market. He recruited a world-class bench of PhDs, thermal scientists and engineers, oversaw the advancement of the underlying thermal science behind the NeuCool platform, and led Accelsius into the U.S. Department of Energy ARPA-E COOLERCHIPS program, forging the government and national-lab partnerships that helped validate the technology at the frontier of high-density compute. He also secured the company's strategic investors and OEM relationships, including Johnson Controls and Legrand, and built the operating footprint that today produces NeuCool systems at the company's expanded Austin facility.
"Founding Accelsius and helping establish two-phase liquid cooling as a foundation for AI infrastructure has been the most rewarding chapter of my career," said Josh Claman, Executive Chairman of Accelsius. "We have assembled a remarkable team, the technology is proven, the customer momentum is real, and the platform is ready to scale. John has been a trusted partner on our board, and his operating record in this exact industry is the right fit for what comes next. As Executive Chairman, I will remain fully devoted to Accelsius, working alongside John on the strategic partnerships, customer relationships and capital strategy that will define our next chapter."
The leadership transition will be effective July 6. Accelsius remains headquartered in Austin, Texas, with manufacturing operations recently expanded to support the rapid global rollout of its NeuCool product family.
About Accelsius
Founded by Innventure, Inc. (NASDAQ:INV), Accelsius empowers data center operators and AI neoclouds to achieve their business, financial and sustainability goals through advanced cooling solutions. The proprietary NeuCool® platform provides best-in-class thermal efficiencies through a safe, two-phase, direct-to-chip liquid cooling system that scales from single racks to entire data centers. For more information, visit accelsius.com or follow us on LinkedIn.
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