Who hasn't sung the praises of air conditioning on a sweltering summer day? But who do you have to thank for this refreshing convenience? The short answer to that question is Willis Carrier, an American engineer credited with inventing the first modern air conditioner. However, the idea of using evaporated water — or other liquids — to cool off a muggy space far precedes Carrier's 1902 invention. The first known systems that used water to cool indoor spaces were created by the ancient Egyptians, who lowered the temperature in their homes by hanging wet mats over their doorways. The evaporated water from the wet mats reduced indoor air temperatures and added refreshing moisture to the dry desert air. Not long after the Egyptians beat the heat with their doorway mats, the Romans developed a primitive air conditioning system by utilizing their famous aqueducts to circulate fresh water through indoor pipes, a method that significantly reduced the air temperature inside stuffy villas.

Of course, it wasn't until long after the Romans had their time in the sun that the principles of modern air conditioning were developed. In 1758, American statesman and inventor Benjamin Franklin, along with John Hadley, a professor at Cambridge University, began experimenting with the refrigerating effects of certain liquids. In previous studies, Franklin had determined that the refrigerating effects of a liquid are related to how quickly it evaporates. He and Hadley expanded on this finding by using ether and a bellows to cool down a mercury thermometer to 25 degrees below freezing. This experiment prompted Franklin to remark in his journal about the possibility of freezing to death, even on a warm summer's day. This observation by Franklin was a foreshadowing of things to come. In 1820, British inventor Michael Faraday was also experimenting with the refrigeration properties of gases when he discovered that, by compressing and liquidizing ammonia and then allowing it to evaporate, he could cool the air inside his laboratory.

Several decades after Faraday made his discovery with ammonia, a Florida physician named John Gorrie developed a machine to keep yellow fever patients cool. Gorrie's machine used compressed air and water to create an open cooling system. Patented in 1851, Gorrie's "cold air machine" was the first patented invention that facilitated mechanical refrigeration, as well as the first to resemble a modern air conditioner.ac unit capacity calculator But it wasn't until 1902 that the history of air conditioning really began to heat up. central ac unit not coldIn that year, a young engineer named Willis Carrier was tasked with the chore of creating a system for treating the air at the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn, N.Y. Printing company executives found that excessive humidity at its printing plant wreaked havoc on the color register used for fine, multi-color printing.mobile air conditioning units for hire

By 1903, Carrier had designed a system of chilled coils that maintained a constant, and comfortable, humidity of 55 percent inside the Sackett-Wilhelms printing plant — the equivalent of using 108,000 pounds of ice daily to cool the plant. The modern air conditioner was born. [See also: Science of Summer: How Does Air Conditioning Work?] Not long after Carrier invented his game-changing air conditioning machine, a mill engineer named Stuart Cramer created a similar ventilating device to add water vapor to the stifling air inside of textile plants. While Cramer was the second person to develop such a device, he was the first to coin the term "air conditioning" to describe the purpose of his invention. Air conditioning continued to be used in plants and mills throughout the early 1900s, but it wasn't until 1914 that this modern convenience was installed for the first time in a private home. In that year, a Minneapolis millionaire named Charles Gates hired Carrier to install an air conditioner in his mansion.

By the 1920s, scores of commercial businesses jumped on the air conditioning bandwagon, installing huge (by modern standards) and toxic (they used ammonia as a coolant) air conditioning devices in their stores. The expansion of air conditioning into American homes was stalled during the Great Depression and World War II, but by the 1950s, those who could afford it began adopting this modern convenience by the thousands. Follow Elizabeth Palermo on Twitter @techEpalermo, Facebook or Google+. We're also on Facebook & Google+. Born November 26, 1876, in Angola, New York Earned engineering degree from Cornell University in 1901 Started working at Buffalo Forge Company in 1901 Designed the world’s first modern air conditioning system in 1902 Developed Rational Psychrometric Formulae in 1911 Founded Carrier Engineering Corporation in 1915 Awarded honorary doctorates from Lehigh University (1935) and Alfred University (1942) Died October 7, 1950, in New York City

Inducted into the National Inventors Hall of Fame in 1985 Named one of TIME magazine’s “100 Most Influential People of the 20th Century” in 1998 Willis Carrier would grow up to solve one of mankind’s most elusive challenges – controlling the indoor environment. As a child, though, he had difficulty grasping the concept of fractions. Realizing his struggles, his mother taught him by cutting whole apples into various-sized fractional pieces. He later said this lesson was the most important one that he ever learned because it taught him the value of intelligent problem-solving. Willis Carrier: The Inventor of Modern Air Conditioning Genius can strike anywhere. For Willis Carrier, it was a foggy Pittsburgh train platform in 1902. Carrier stared through the mist and realized that he could dry air by passing it through water to create fog. Doing so would make it possible to manufacture air with specific amounts of moisture in it. Within a year, he completed his invention to control humidity – the fundamental building block for modern air conditioning.

Carrier Enables Industries to Flourish The “Father of Air Conditioning,” Willis Carrier’s invention gave rise to numerous industries that power our economy today. Manufacturing of everything from baked goods to wartime supplies was made possible by air conditioning. Air conditioning led directly to summer movie blockbusters as people came to cooled theaters to escape the heat. The precise control of temperature and humidity made possible by his invention even enabled shopping malls, transatlantic flight, and the computers and servers that power the Internet. Bringing Comfort to the World Willis Carrier recognized early on that climate, comfort and production requirements would determine the value of air conditioning. From the beginning, he began to develop a network of international dealers, distributors and customers. Success with early installations in Europe and Asia were indicators of air conditioning’s universal application across international borders.