sibster what you have described is an absorption (or sometimes called sorption) system that is much more complicated. it seems bizzare that the boat or caravan fridges can use calor gas to make a fridge work, but that's what they do.

a heat pipe is a much simpler device. it is just a pipe with a refrigerent encapsulated in it which allows them to conduct away much more heat than just a pipe.

as Ollie MK5 Turbo says, they are being used increasingly in computers to take heat out of the cpu, but their original use was to improve the efficiency of building dehumidifiers.

all that they do is conduct the heat away from a hot place to a colder place, but much more effectively than a simple pipe would do.

in a chargecooler application, i would envisage a heat exchanger filled with many columns of heat pipes, with the boost air passing over them. the tops of the heat pipes would go into a header tank type arrangement with cold water pumped through it, then a radiator to remove the heat from that water, much like a standard separate chargecooler system that are commonly used now.

the theory should be that it should work much more efficiently for a given volume.