Institute of Energy Systems and Environment, Riga Technical University, 1, Kronvalda, LV-1010, Riga, Latvia
C. Rochas
Institute of Environment and Energy Systems, Faculty of Energy and Electrical Engineering, Riga Technical University, Kronvalda blvd. 1, Riga, LV 1010, Latvia
D. Blumberga
Institute of Environment and Energy Systems, Faculty of Energy and Electrical Engineering, Riga Technical University, Kronvalda blvd. 1, Riga, LV 1010, Latvia