That's the kind of story that would probably well past the U.S. manufacturer Hewlett-Packard.
The marketing brochure of its Chromebox spoke indeed about a fanless design, to ensure quiet operation and prevent infiltration of dust inside the housing.
Except that a hardware tester raging on the platform YouTube, a Lyon Siedman, found a suspicious buzzing noise when he looked at the case of the device.
Seeking documentation of removal on the website of Hewlett Packard, he discovered pictures where you can see a fan.
Not sure that the accusations of false advertising that come with the discovery are highly valued by HP and the person responsible for the blunder is still in the ranks. You're all defendants in cases, if you are planning to buy HP Chromebox. It is not fanless.