The Department of Energy has funded a program entitled "Energy Smart Data Center" (ESDC).  The program is being executed at the Pacific Northwest National Labs (PNNL).  Phase I of the program started June '04, and was completed in July '05.  The program is currently in its second phase, which is due to be wrapped up July '06.  The primary objectives of the ESDC program have been to demonstrate the ability to implement an advanced liquid cooling technology (spray cooling) that will result in improved system uptime, a high overall facility energy efficiency (via coefficient of performance, i.e., COP), and a low overall total cost of ownership (TCO).  Under Phase I of the program, a full rack of HP rx2600 2U servers was converted from air-cooling to spray cooling.  Prior to the conversion, the air-cooled servers were performance benchmarked at PNNL.  The air-cooled servers were then converted to spray cooling, installed as part of PNNL's main cluster, and performance benchmarked.  An infra-red imaging study was also conducted in order to "quantify" the impact of a spray cooled rack on PNNL's facility.  Since installation, the uptime of the rack of spray cooled servers has been tracked, and the facility COP and TCO determined for a number of different scenarios.  Related results will be presented.  The working coolant is 3M's PF5050 (a perfluorocarbon).  The environmental impacts of perfluorocarbons will be discussed.  Results from the system performance benchmarking using some subset of the NASA NPB-2 Benchmark suite will also be presented.