The Effect of Fill Ratio on Performance and Heat Transfer Coefficient of Thermosyphons Evaporator and Condenser

Thermosyphons has a special position in field of energy recovery and saving regarding to their unique performance. In the present research، the effect of the fill ratio on the heat transfer rate in the evaporator and condenser sections as well as the overall performance of the thermosyphon was studied. For this purpose، a one meter copper thermosyphon tube with an inside and outside diameters of 17. 5 and 19 mm was fabricated. The length of the evaporator، adiabatic and condenser sections were 40، 20 and 40 cm respectively. The deionizer water with the fill ratio of 0. 3، 0. 5 and 0. 8 were used as working fluid in experiments. The temperature was recorded at various points on the thermosyphon as well as at the inlet and outlet streams of the condenser. The maximum performance among three cases was observed at the 0. 5 fill ratio. In addition، the maximum heat transfer rate in the condenser and evaporator was happened in this ratio.