The efficiency of two-phase closed thermosyphon (TPCT) with nanofluid as working fluid under magnetic field effect was investigated experimentally. In this study, silver/water nanofluid with different concentration (20 to 80ppm) is tested. Also, magnetic field with various strength (0.12, 0.35 and 1.2 T) exerted to TPCT by permanent magnet. It was seen that the TPCT heat transfer performance an...