1. Technical University of Sofia,Dept. of Hydroaerodynamics and Hydraulic Machines,Sofia,Bulgaria
2. Technical University of Sofia,College Energy and Electronics,Dept. Energy and Mechanical Engineering,Sofia,Bulgaria
3. Technical University of Sofia,Centre for Research and Design in Human Comfort, Energy and Environment (CERDECEN),Sofia,Bulgaria
4. Engineering and Heat Engineering Technical University of Sofia,Faculty of Engineering and Pedagogy of Sliven,Dept. Mechanics Mechanical,Sliven,Bulgaria