Servers Powered by a 10kw In-rack Proton Exchange Membrane Fuel Cell System

To improve the reliability and the energy efficiency of datacenters, as well as to reduce infrastructure costs and environmental impacts, we demonstrated and evaluated the use of a 10 kW Proton Exchange Membrane Fuel Cell (PEMFC) stack and system for powering the servers in a data center. In this study, we designed, tested and demonstrated a PEMFC system as a Distributed Generation (DG) prime mover that has high reliability and efficiency for both steady state and dynamic operations. The 10kW PEMFC stack and system was designed to power a server rack and eliminate the power distribution system in the datacenter. The steady state electrical properties such as efficiency and polarization curves were evaluated. The ramp rate and dynamic response of the PEMFC system to server and system dynamics was also characterized and can be used to determine energy storage requirements and develop optimal control strategies to enable the dynamic load following capability. INTRODUCTION Fuel cell technology is an attractive electrical power generation technology receiving a great deal of recent attention. Fuel cells directly convert fuel to electricity. The direct electrochemical conversion of fuel allows for high fuel-toelectric conversion efficiencies without pollutant emissions. As reliable and environmentally friendly power sources, fuel cells can potentially play a very important role in data centers. A simple way of utilizing fuel cells as data center power sources is to connect them in grid parallel or backup generators. For example, eBay equipped its Utah data center with fuel cells from Bloom Energy [1] in a grid parallel configuration. The data center industry has experimented with centralized fuel cells through simulation and pilot installations. Such studies and demonstrations are mainly focused on: 1) installing high temperature fuel cells (several MW capacity) to power an entire data center [2-4], 2) advancing combined heat and power technology in the data center for better efficiency [5, 6], and 3) performing economic and energy efficiency assessments [6, 7]. Manno [5] simulated a cogeneration system based on a natural gas membrane steam reformer producing a pure hydrogen flow for electric power generation in a PEMFC. The study demonstrated that heat is recovered from both the reforming unit and the fuel cell in order to supply the needs of the data center. The possibility of further improving data centers’ energy efficiency adopting DC-powered data center equipment is also discussed. Qu [6] reported a comprehensive performance assessment for a combined cooling, heating and power (CCHP) system with fuel cell in a data center. Data analysis and simulation results demonstrated great advantages of CCHP systems over conventional systems in the data center with regard to energy, environment and economic performance. Hagstotz [7] described the use of a molten carbonate fuel cell for data centers and telecommunication installations supplying cooling and electricity. Few of these published studies pertain to utilizing a midsize PEMFC system within the server rack that directly generates power, as is accomplished in this effort. A key concern of using fuel cells to power servers directly is the load following capability of the fuel cells. Fuel cells themselves can usually respond sufficiently fast to changes in