An engine cooled only by thermosiphon is susceptible to overheating during prolonged periods of idling or very slow travel when airflow through the radiator is limited, unless one or more fans are able to move enough air to provide adequate cooling.
32.
In the temperate scenario this is sufficient to heat 200 litres of water by some 17 �C . In the tropical scenario the equivalent heating would be by some 33 �C . Many thermosiphon systems have comparable energy output to equivalent active systems.
33.
This work lead to the commercialization of flat panel solar water heaters, and solar pool heaters, marketed as Northrup Energy products directly and via dealers, with particular success in Hawaii, where solar thermosiphon systems could be used with antifreeze.
34.
Such a gravity aided heat pipe is known as a thermosyphon . ( See also : Perkins tube, after Jacob Perkins . ) Please note that a heat pipe thermosyphon is different than a thermosiphon, which transfers heat by single phase natural convection heat transfer in a loop.
