A New Edge Micro Data Center and its Passive Thermosyphon Cooling System at TUe: Cooling System Thermal Performance Tests

A new innovative Edge Micro Data Centre and its new passive two-phase cooling system are presented here. EMDC's are hyperconverged heterogenous hardware capacities ranging from 1.8kW up to 500kW. HIRO, providing Powerfull Edge as a Service (PEaaS) is seeking very high cooling energy efficiency (PUE approaching 1.0) and solutions to re-use waste heat from their locally installed EMDC's and edge services that are supporting the big data processing and AI of their customers (smart hospitals, Industry 4.0, 5G/6G MEC, smart cities, smart energy grids). The smallest EMDC with 11 nodes (8 processing and acceleration, 1 ethernet switch, 1 PCIe switch and DC power) is used in the test setup. The gravity-driven loop thermosyphon cooling system is composed of a compact monoblock for insertion and cooling of 11 EDMC nodes, a riser and downcomer and a compact aircoil condenser cooled by several fans (or by natural convection). The heat of the EDMC nodes is removed by 11 thermal bridges in the monoblock evaporator. In demonstration “stress” tests run at TUe in The Netherlands, monitoring all individual node temperatures and energy consumptions, the cooling system achieved very high cooling performance during all the tests. Defining the PUE here to be equal to the total energy consumption including fans divided by that of only the computer itself, at maximum heat load the PUE was only 1.034 while at medium heat loads using lower fan speeds values as low as 1.007 were recorded and at heat loads of 186 W and below, the fans could be turned off for completely passive cooling operation. The IP of this thermosyphon cooling for EMDC's is property of JJ Cooling and HIRO and is subject to further research. HIRO market launch of their first product line of EMDC's is planned for Q3 2024.