Performance study of a Vanadium Redox Flow Battery (VRB) for use in green data centers

This paper analyses the parameter dependence during the charging process of a Vanadium Redox Flow Battery (VRB) for a system-aware green data center which has distributed sources of energy production and amenable to flexible load scheduling. One of the key features of a flow battery is the ability to control the flow rate and current during the charging process. The flexibility however has a direct effect on charging time and efficiency which calls for a detailed performance study with various modes of charging. An electrical model of a kW scale VRB having an operating SOC range of 15-85% is presented. The presented model considers a 15 cell battery with current range of 80-160 mA/cm-2, overall membrane area of 780 cm2 and a flow rate range of 2-6 L/min. The results obtained show that there is a trade-off between the charging time and the energy capacity depending on the charging current and the flow rate. This work would aid the process of charging optimization by selecting various modes of operation of VRB, depending on the weightage given by the system for charging time or the energy efficiency.