While experimenting with my highly effective water suck'n'steam plasma engine I noticed how most of the time the water was being "Sucked" in. The reason was that a low pressure zone was appearing in the oven the reason? I think the rising water vapour was sucking out the air creating a low pressure zone.

If this i what was happened with the introduction of heat transfering walls (stopping highpressure ovens interfering) I can see a new range of highly acurate and effective (the current fans are anything but effective) fan systems.