3URVSHFWVIRUK\GURJHQSURGXFWLRQLQRLOVKDOHSURFHVVLQJLQGXVWU\ LQ(VWRQLDLQLWLDODVSHFWVRIOLIHF\FOHDQDO\VLV 0HHOLV(OGHUPDQQ$QGUHV6LLUGH-XOLMD*XVFD Department of Thermal Engineering, Tallinn University of Technologies, Ehitajate tee 5, 12616, Tallinn, Estonia