There is quite a hobbyist field in Stirling engines in this range. For example, Google "5hp Stirling engine," and you should get some videos and plans.
Waste heat recovery is typically at too low temperature differentials to be very effective; I think concentrated solar collection has better potential.
__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Solar can work OK, waste heat depends on the source temperature, etc.
Problem with getting hot air (Stirling is a specific design) engines to run efficiently is you need to pressurize the working fluid and air isn't a good choice. The rare gasses that work well tend to leak right through metal so you need to move to ceramic.
Philips did a lot of work on hot air engines back in the 70's.
__________________
It was burning when I put it down!
Use Google (usual disclaimer - other internet search engines are available).
__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Do you want to use the Stirling engine for waste heat recovery, or power the engine with waste heat? Attention to waste energy recovery should start with designing your question to allow efficient answers and less bs entropy. (it can get very deep).
Stirling Engines
Re: stirling engines
