External combusion engine? In 1816, it was state of the art. Cheap, efficient and safe, Robert Stirling's hot air engine was used in various ways (think pumping water and powering small toys), but none was more intriguing than powering hot air fans. The fans run quietly and work just about anywhere, so when first introduced they provided relief for everyone from missionaries in hot climates to those suffering during the 1918 Influenza Epidemic.
If you're not convinced these fans are still cool by today's standards, the following video of a Jost hot air fan powered by a Stirling hot air engine should do the trick.
This Ky-Ko hot air fan is essentially silent, and is powered by lamp oil.
For more on hot air fans and Stirling hot air engines, read Renae Vander Schaaf's feature on Wesley Bosch's hot air fan collection from the January 2012 issue of Farm Collector.