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 VDC 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 VDC 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.