1. School of Electrical and Computer Engineering, National Technical University of Athens, Zografou, Greece
2. School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
3. Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, U.K.
4. Energy Advisory, WSP, Glasgow, U.K.
5. EES, AIT Austrian Institute of Technology, Austria
6. National Technical University of Athens, Athens, Greece