A1 Digital’s cloud provider Exoscale is trialing a direct liquid cooling system in its Vienna, Austria, data center.

The direct liquid cooling system, developed by Austrian company Diggers, sees server blades sealed in a cold box.

As reported by The Register, the cold box prevents air from getting in or out, while cold plates with microchannels bring the cooling liquid to the GPUs and CPUs. Diggers claims that the system removes the need for a cold aisle, reducing energy consumption by 50 percent and achieving a PUE of 1.05

Exoscale’s COO Antoine Coestsier told The Register that the increasing density demands in data centers, along with growing energy costs, and the desire to improve sustainability has driven the company to trialing the solution.

The cold box is Diggers’ fourth-generation product, with the company previously selling immersion cooling solutions. Diggers CEO Martin Schechtner said to The Register of the cold box solution: “We basically achieve the same technical results as immersion cooling, but have no mineral oil and no maintenance issues. Everything is easy to change. You can swap memory and drives. There’s no oil dripping.”

The cold plates are made from aluminum, to prevent rusting, and one plate can cool two GPUs – one on either side of the plate. Each cold box can contain four server blades mounted vertically.

Exoscale’s deployment at its Vienna data center is currently made up of eight cold boxes, with a total of 80kW of compute capacity. Coestsier said that while currently a proof of concept, the company plans to “ramp it up” as the solution can handle the most powerful GPUs available.

The water coming out of the cold box is around 50°C (122°F) and can be used either on-premise for heat reuse, or sent to a local heating network.

Exoscale is A1 Digital’s European cloud and hosting platform. The company has data centers in Frankfurt, Munich, Vienna, Geneva, Zurich, and Sofia. The company has two data centers in Vienna – one located in the Arsenal, a former military complex, and the other in the A1 Next Generation Data Center, which Exoscale describes as one of its most modern data center facilities.

The A1 data center was launched in 2018 and saw A1 Digital investing €40 million ($41.87m) in the facility. The building spans 8,000 sqm (86,111 sq ft) with 2,550 sqm (27,448 sq ft) of data center white space. It has two 6MW of connected load, and runs on 100 percent renewable energy. At launch, it had a PUE of under 1.4.

Diggers was founded in 2019, starting with a proof of concept immersion cooling before landing on the direct-to-chip system in 2020-2021. The company also has data center-as-a-service and Infrastructure-as-a-Service offerings.