Lumen Labs locks $120M Series C to scale micro data centers across Europe

Tech · 5 min read

Lumen Labs, which builds modular, carbon-optimized micro data centers, announced a $120 million Series C round led by Horizon Capital with participation from Greener Ventures and several strategic cloud partners. The company plans to use the capital to expand manufacturing capacity in Poland and Spain and accelerate deployments in secondary European cities.

The startup sells prefabricated racks and integrated cooling systems designed to host AI inference appliances and edge-optimized accelerators. Lumen Labs says its next-generation racks will support direct liquid cooling and power density suitable for cluster-level LLM inference, enabling lower latency for on-prem AI deployments.

Executives emphasized sustainability: each unit integrates heat-reuse systems for district heating and operates on a modular service model to reduce hardware churn. Customers across telecom, autonomous vehicle testing, and digital media are piloting installations set to go live later this year.