1. Ph.D. Student and Mechanical Engineer, Laboratory of Steam Boilers and Thermal Plants, National Technical Univ. of Athens, Heroon Polytehniou 9, Zografou, 15773 Athens, Greece (corresponding author).
2. Electrical Engineer, Laboratory of Steam Boilers and Thermal Plants, National Technical Univ. of Athens, Heroon Polytehniou 9, Zografou, 15773 Athens, Greece.
3. Associate Professor, Laboratory of Steam Boilers and Thermal Plants, National Technical Univ. of Athens, Heroon Polytehniou 9, Zografou, 15773 Athens, Greece.