Energy efficient DC-grids for commercial buildings

Modern power electronics enable the efficient supply of almost all kinds of electric applications in commercial buildings, e. g. lighting, IT- and telecommunication equipment, as well as speed-controlled drives in heating, cooling and ventilation applications. This potential can be used more effectively using a 380 V_DC Grid compared to a traditional AC Grid in commercial buildings. The European ENIAC R&D project consortium DC Components and Grid (DCC+G) is developing suitable, highly efficient components and sub systems for 380 V_DC grid to show the benefits of DC grid concept on test site in an office environment. The newly developed DC Grid components and their integration into a generic system are presented in this paper. The targeted overall efficiency saving compared to AC grid is 5% and the energy conversion from PV is calculated to be 7% higher compared to traditional PV inverter conversion. This paper also shows the layout of the office demonstrator at Fraunhofer Institute in Erlangen, Germany, and describes general benefits of a DC Grid system.