Seven years ago, the idea of submerging mining hardware in liquid was met with skepticism. Gary Testa, President and CEO of Engineered Fluids, recalled the blank stares he received when he first proposed putting miners in fluid. By 2022, he told the room, everyone on the show floor was doing immersion mining, and millions of devices were running in fluid. The conversation has shifted from the benefits of immersion to the practical considerations required to build a system that remains profitable over its lifetime.
Testa took the stage at Mining Disrupt Miami 2022, held July 26–28, 2022, to dissect these practical pitfalls. While the industry has scaled rapidly, the physical constraints of heat dissipation and power efficiency remain constant. Testa highlighted the growth of Engineered Fluids, which manufactures dielectric coolants for the crypto industry. The company has expanded its production capabilities significantly, moving its research and development lab from San Francisco to Saint Petersburg, Florida, and acquiring a new facility in Tyler, Texas.
From Blank Stares to Tanker Trucks
The scale of immersion mining has changed dramatically since its inception. Testa noted that the company’s logistics have transformed from small-scale shipments to industrial transport. He pointed out that Engineered Fluids is now regularly shipping tanker trucks filled with 25,000 liters of BitCool. This shift in volume reflects the industry’s maturation and the increasing demand for reliable dielectric coolants.
Now we are regularly shipping tanker trucks filled of 25 000 liters of bitcool
Gary Testa · 1:48
Engineered Fluids reported that over 1.72 million devices are currently immersed in their fluids globally. Many of these devices have been in operation for more than three years, with some running at full capacity for more than seven years without a failure. Testa attributed this longevity to the work of the company’s chief scientist and chemist, who invented the products. This track record suggests that the fluid itself is no longer the point of failure; rather, the surrounding infrastructure is where the challenges lie.
The Hidden Heat: Power Supply Inefficiency
As mining operations push for higher hashrates through overclocking, the thermal dynamics of the facility change dramatically. Many operators focus on the heat generated by the ASICs themselves, often overlooking the secondary heat generated by the power supply units (PSUs). Testa argued that this oversight is a critical design flaw. When a miner is overclocked, it consumes more electricity, and a portion of that additional electricity is lost as heat within the power supply before it even reaches the chip.
What we don't think about is well what's the impact on the ambient air temp
Gary Testa · 7:23
Engineered Fluids' standard flow rate for BitCool is 2.5 liters a minute per kilowatt. Overclock a miner by 40 percent, Testa asked, and are you only adding heat, or do you also need more flow and a bigger dry cooler? Testa emphasized that power supply inefficiency is a major contributor to total thermal output. If a facility is designed based solely on the nominal power draw of the miners, it will be under-sized for the actual heat rejection required. This misalignment leads to higher ambient temperatures, which in turn reduces the efficiency of the cooling system.
Scaling the Plumbing: The Hard Parts
One of the most persistent challenges in scaling immersion facilities is the physical infrastructure required to move the coolant. Tanks, fluid, and dry coolers are modular; they can be added in stages. Piping and pumps, however, are fixed. Once the facility is built, retrofitting the plumbing to handle increased flow rates is a complex and expensive undertaking. Testa advised operators to plan for their end-state capacity from the beginning, rather than trying to scale up incrementally.
It is easy to scale tanks fluid even dry coolers but it's very difficult to go back tear
Gary Testa · 8:22
Supply chains made this worse. Dry coolers and EC fan motors were quoted at 48 to 60 weeks, so Engineered Fluids began building its own dry coolers in Florida from US-made components, delivered in about 14 to 15 weeks. Large pumps, in the 25 to 50 horsepower range, were now stretching out too. This supply chain bottleneck makes late-stage modifications particularly risky. Testa recommended designing the pump system to accommodate future expansion, either by installing all pumps upfront or by leaving designated spots in the system for future installation.
Geography and Automation: The Final Considerations
The efficiency of an immersion cooling system is heavily influenced by its geographic location and the placement of its dry coolers. Ambient air temperature determines the baseline for heat rejection. For dry coolers, he said, it is location, location and ambient temperature: where the site is sets the air temperature the coolers work against, and where the coolers sit on the site, and how they are spaced, decides how well they reject heat.
Last came automation versus manual control. Everything can be automated, Testa said; the questions are whether you can afford it and whether you need it on day one, or can add it later.
Testa concluded by emphasizing the financial implications of ignoring these engineering details. He warned that underestimating power supply inefficiency and heat generation leads to a system that fails to meet its financial projections. Ignore it, he said, and you build a system “incapable of meeting the financial model that you sold your investors.” When this session was recorded, Bitcoin traded at $21,268; on October 11, 2026 it was $82,952.
that inefficiency creates more heat and if you don't account for that in your system
Gary Testa · 12:23