In this paper, the effect of ammonia, chloroform and pure distilled water as different working fluids, its thermal performance is investigated in thermosyphon heat pipe with or without fins at closed room condition. One thermosyphon heat pipe without fins and anther thermosyphon heat pipe with internal circumferential fins on evaporator section and condenser section with internal and external circumferential fins. Model describes the detail thermal behavior and heat transfer of thermosyphon heat pipe with or without fins, initially by theoretical model and then by experimental model. These parameters included important tube size design parameters and thermal parameters (flow rate, heat loss, the effect of the finned heat pipe parameters after incorporating evaporation and condensation of the heat pipe working fluid. etc).

Keywords : Thermosyphon Heat Pipe, Working Fluid, Fins.