Timeline for its historyhttp://www.popularmechanics.com/home/how-to/a7951/a-brief-history-of-air-conditioning-10720229/

Without air conditioning, we wouldn’t have certain medications today some medications could only be studied and developed in a cool environment.

The first air conditioner was invented by Willis Carrier in 1902. He worked at a publishing company and needed a way to keep his paper from expanding and ink from running.

Also, air conditioners can provide a way of ventilating or exhausting air as well as heating it. Link Title

If you tried to buy an in-window air-conditioning unit in the 1940s, you'd spend about about $350 in 1940s money, which in today's dollars is almost $3,500. Link Title

How does AC work?
http://energyquest.ca.gov/how_it_works/air_conditioner.html

What is AC? https://www.trane.com/residential/en/resources/hvac-basics/how-does-an-air-conditioner-work.html

Photo 1(https://i.stack.imgur.com/iXrvX.png)

Photo 3 [Link Title] (http://alldayaircooling.com/wp-content/uploads/2015/07/how_ac_works.jpg)

Photo 4 (http://www.conservationphysics.org/aircon/simpl_ac.jpg)