Super conducting heat pipe for solar collector, each pipe is tested at 250 degree condition The heat pipes used in AUCKLAT solar collectors have a boiling point of only 25°CSo when the heat pipe is heated above 25°C, the water vaporizes.This vapor rapidly rises to the top of the heat pipe transferring heat. As the heat is lost at the condenser (top), the vapor condenses to form a liquid (water) ...