1.      Slesian Technical University, Poland-Energy conservation (2 joint paper published in journals)

2.      Laughborough University of Technology, United Kingdom - Building modeling (2 joint papers published in international journals).

3.      Czech technical university, - LP research of energy systems (3 joint papers published in international journals)

4.      Timisoara Technical University -Energy conservation (2 joint papers published in journals)

5.      Agricultural university of Athens, Greece-air to earth heat exchangers (2 joint papers published in international journals)

6.      Nagoya University, Japan- Simulation research of HVAC systems by using solar collectors and Heat Pumps.

7.      Lincoping university of technology, Sweden- MILP research of energy systems ((2 joint papers published in international journals)

8.      Higher Technical Institute, Nicosia, Cyprus- Application of artificial neural networks to predict thermal behavior of buildings (2 joint papers published in an international journal).