Air conditioning
In 1902, the first modern electrical air conditioning unit was invented by Willis Carrier in Buffalo, New York. After graduating from Cornell University, Carrier found a job at the Buffalo Forge Company. There, he began experimenting with air conditioning as a way to solve an application problem for the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn, New York. The first air conditioner, designed and built in Buffalo by Carrier, began working on 17 July 1902.
Rider-Ericsson Engine Company
In his patent of 1759, Henry Wood was the first to document the powering an engine by the changing volume of air as it changed temperature. George Cayley was the first to build a working model in 1807. The Reverend Robert Stirling is generally credited with the "invention" of the hot air engine in 1816 for his development of a "regenerator" which conserves heat energy as the air moves between the hot and cold sides of the engine. Technically, not all hot air engines utilize regenerators, but the term hot air engine and Stirling engine are sometimes used interchangeably.