1. Faculty of Civil Engineering, Department of Building Services, Transilvania University of Brasov, Brasov BV 500152, Romania
2. Faculty of Mechanical Engineering and Mechatronics, Thermotechnics, Engines, Thermaland Refrigeration Equipment Department, University Politehnica of Bucharest, Bucharest B 060042, Romania
3. Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720, USA