|Open Cycle||Closed cycle||Description|
|Direct heating||These are air engines have an open furnace that heats the working fluid externally. This means that the working fluid is heated indirectly and not directly.
The engine works on an closed cycle. The same air is used again and again, heated up to do work, and then cooled down before starting the cycle again; the air is never rejected into the atmosphere.
Examples of closed cycle hot air engines:
- The Stirling engine,
- The Rider hot air engine,
- The Lehmann air expansion engine.
|Indirect heating||Closed cycle engine|
|1827||Parkinson & Crosley||England||Parkinson & Crosley Motive Engine|
|1833||Ericsson||Sweden / England||Ericsson caloric engine|
|1838||Franchot||France||Le moteur à air chaud de Franchot|
|1855||Franchot||France||Le moteur sériaire à air chaud de Franchot|
|1875||Rider||America||Rider's hot air engine|
|1881||Robinson||England||Robinson's hot air engine|