High performance datacenters that are being built and operated to ensure optimized compute density for high performance computing (HPC) workloads are constrained by the requirement to provide adequate cooling for the servers. Traditional methods of cooling dense high power servers using air cooling imposes a large cooling and power burden on datacenters. Airflow optimization of the datacenter is a constraint subject to a high energy penalty when dense power hungry racks each capable of consuming 30 to 40 kW are populated in a dense datacenter environment. The work documented using a simulation model (TileFlow) in this paper demonstrates the challenges associated with a standard air cooled approach in a HPC datacenter. Alternate cooling approaches to traditional air cooling are simulated as a comparison to traditional air cooling. These include models using a heat exchanger assisted rack cooling solution with conventional chilled water and, a direct to node cooling model simulated for the racks.
These three distinct data center models are simulated at varying workloads and the resulting data is presented for typical and maximal inlet temperatures to the racks. For each cooling solution an estimate of the energy spend for the servers is determined based on the estimated PUEs of the cooling solutions chosen.