The aim of this study was to investigate the effect inserting a new internal tube packing (TP) on thermal performance thermosyphon heat pipe (THP). THP made from copper with an inner diameter 17.4 mm and length 600 mm. had central disc two tubes soldered onto both sides transport vapor condensate. upper or riser 8.3 300 long; it connected hole in side steam condenser section. lower downcomer 5 ...