Cooling Data Center Podcast

What if the biggest barrier to scaling liquid cooling isn't the engineering, but an industry-wide habit of keeping things secret that don't need to be kept secret?
In this episode, Bill Kosik of HED and chair of The Green Grid's AI Impacts working group joins Robert for a genuinely insightful conversation about the long view of data centre design, and why the lessons from IBM's water-cooled mainframes still apply to today's 300kW racks.
From his time at Hewlett Packard's facilities design group working on liquid-cooled supercomputing, to leading mission critical projects at HED today, Bill brings three decades of pragmatism to an industry that often confuses novelty with progress.
Together, they explore:
Why liquid cooling isn't new technology and what the 1980s mainframe era can still teach us
How the manufacturers stepping up with full liquid-cooled product suites unlocked the current scale
The inflexion points reshaping cooling design, from 5kW cabinets a decade ago to 300kW racks today
Why the industry's culture of secrecy is fuelling public misunderstanding around water use, noise and vibration
How global end users, not just regulators, are driving sustainability standards in the United States
The retrofit opportunity hiding in Tier IV enterprise data centres being repurposed for small-scale AI
Why ASHRAE 90.4 becoming part of energy code means you can't design around it anymore
The case for designing data centres that don't look like distribution warehouses
If you've ever wondered whether 300kW racks will one day feel as routine as 30kW racks do now, or wanted someone to put today's AI build-out in proper historical context, Bill delivers the kind of measured engineering wisdom that's increasingly rare in a hype-driven market.
His take? In five years we'll be sitting around laughing at how we didn't know how to cool a 300kW rack. The history of this industry is one of inflexion points, and the people who recognise them early are the ones who shape what comes next.

What if the biggest barrier to liquid cooling efficiency isn't the technology itself, but the legacy thinking that's keeping temperatures unnecessarily low?
In this episode, Jake Roberts of Excool joins Robert for a refreshingly honest conversation about what it really takes to deliver cooling solutions across global markets, and why the data centre industry's conservative approach might be leaving serious efficiency gains on the table.
From retrofitting existing facilities without ripping out infrastructure to challenging assumptions about water use in cooling, Jake brings practical engineering insight to an industry still debating whether to raise chip temperatures above 20 degrees Celsius.
Together, they explore:
·       Why retrofitting for liquid cooling doesn't have to mean reinventing the wheel or running chilled water everywhere
·       The real efficiency cost of running entire chiller plants at 18 degrees just to handle 20-30% of airside load
·       How indirect cooling units can decouple airside and liquid cooling temperatures for better PUE
·       Why NVIDIA's push toward 45 degree facility water loops could eliminate the need for water chillers entirely
·       The nuanced truth about water use: why a little adiabatic cooling on peak days beats moving the problem to power stations
·       How West Midlands manufacturing heritage enables rapid, bespoke delivery to global markets
·       What speed to market really means when customers need solutions in expedited timelines
If you've ever wondered whether your cooling design philosophy is leaving stranded power on the table, or wanted someone to explain retrofit options without assuming you're starting from scratch, Jake delivers straight talk with engineering credibility. His insight? Pushing temperatures up has such a positive effect on the industry, from sustainability through to cost efficiency, and the ROI on reduced peak PUE is immediate.

What if the biggest barrier to liquid cooling adoption isn't the technology - it's just protecting against what happens when things go wrong?
In this episode, Cassandra Zentner of Actnano joins Robert for a refreshingly practical conversation that strips away the idealism and gets to the heart of why protection matters just as much as prevention - and why automotive-grade coating technology is already more relevant than most people realise.
From her decade protecting Tesla and Rivian autonomous driving systems to bringing 15-20 year warranty-grade protection to data centers, Cassandra brings grounded realism to an industry still assuming leaks and condensation can be completely prevented.
Together, they explore:
·       Why protection is the missing piece in the prevent-detect-protect trilogy
·       The reality behind leak assumptions - catastrophic failures AND slow PG25 coolant buildup both damage expensive chips
·       Why coating technology (not just tighter controls) enables operational flexibility
·       How Actnano's collaboration across chip makers, hyperscalers, and ODMs creates supply chain-wide protection
·       Why condensation concerns and narrow HVAC windows mean data centers are over-engineered for prevention
·       The insurance policy mindset - protecting hundred-thousand-pound investments when infrastructure inevitably fails
If you've ever wondered whether direct liquid cooling protection is essential or wanted someone to explain it without assuming perfect conditions, Cassandra delivers the straight talk with automotive credibility. Her insight? "The data center is the easy environment" - because if it protects against salt, frost, and corrosive gases in EVs, your server boards are already covered.

What if the biggest barrier to immersion cooling isn't technical - it's just understanding what it actually is?
In this episode, Allison Boen of Alcatex and the Open Compute Project joins Robert for a warmly authentic conversation that strips away the jargon and gets to the heart of why single-phase immersion cooling matters - and why it's already more deployed than most people realise.
From her 30-year journey as a self-described "CRAC dealer" (computer room air conditioner specialist) to becoming Shell's Brand Ambassador and OCP's immersion community champion, Allison brings infectious enthusiasm to a technology she discovered in 2014 and hasn't stopped evangelising since.
Together, they explore:
Why Intel's recent warranty certification with Shell and Supermicro changes everything
The reality behind deployment numbers - Shell's Houston facility runs half its 7MW workload on just 2MW of immersion
Why hybrid data centres (not rip-and-replace) are the practical path forward
How OCP's collaboration breaks down ego barriers and creates agnostic TCO tools anyone can use
Why protest signs in tiny Irish villages and Mission Impossible films mean data centres have officially gone mainstream
If you've ever wondered whether immersion cooling is still just "proof of concept" or wanted someone to explain it without the sales pitch, Allison delivers the straight talk with genuine passion. Her advice? "Don't spill it" - because if you need floor drains, you've engineered it wrong.

What happens when you've been testing data centres since before "data centre" was even a term?
In this episode, Dave Wolfenden of Heat Load joins Robert to trace an extraordinary journey from COBOL programming at Heathrow Airport to becoming one of the UK's pioneering data centre commissioning specialists. Starting with Argos heaters and 500kW of rack-mounted units delivered in transit vans, Heat Load has evolved to deploy up to 120MW of testing equipment across 10 articulated lorries.
Dave shares candid insights from over three decades in the industry - from the early days of chaotic rack layouts and liquid CO2 cooling experiments to today's hyperscale pressure cooker where data halls are worth £1M per megawatt per day in lost revenue.
Together, they explore:
How testing has evolved from basic USB sensors to real-time 3D modelling with wireless monitoring
The logistics nightmare of juggling equipment across Europe while customers demand instant deployment
Why immersion cooling adoption is slower than expected (and why Heat Load is ready anyway)
The shift from owner-operators to hyperscalers - and what that means for the industry
If you want to understand how data centre commissioning really works - from the sharp end of delivery deadlines to the evolution of an entire industry - this conversation delivers the unvarnished truth from someone who's been there since day one.