Do you know how many citizens in the United States have air conditioning in their homes? The fact is that nearly 100 million out of 7 billion citizens in the United States have air conditioning in their homes. Air conditioning units initially began to be used in 1902, but were not officially called “air conditioners” until 1906, by Stuart Cramer (Air Conditioning and Refrigeration Timeline). As late as the 20th century, people tried to achieve air conditioning by doing things like draping saturated rugs indoors and installing water-powered fans. Leonardo DeVinci built a mechanical ventilator that was the first of its kind. The cycle that air goes through before entering your home is called the refrigeration cycle. The definition of the refrigeration cycle is; a sequence of thermodynamic processes through which heat is removed from a cold body and expelled towards a hot body. The refrigeration cycle is composed of nine different equally important components which are: two fans, a liquid line, a suction line, a compressor, a condenser, an evaporating coil, a measuring device and a filter for filtration of the air flowing through the air. home.The creation of the air conditioning unit by Willis Haviland Carrier was the launch of the modern idea.But it was thanks to Benjamin Franklin and John Hadley, who originally discovered that the evaporation of alcohol and other evaporated volatile liquids could cool an object enough to freeze water .HVAC stands for Heating, Ventilation and Air Conditioning. HVAC systems can be used for residential, commercial or industrial buildings. The HVAC unit is also responsible for changing and redistributing the outside air. In this way, the system ta...... half of the paper ......s. They must therefore supervise the works of these people. For small buildings, contractors typically size and select HVAC systems and equipment. Many industry-standard design and sizing guides are available from trade associations such as AirConditioning Contractors of America (ACCA). For longer buildings, the law may require mechanical, architectural, or building services engineers to design and specify the HVAC systems. Specialized mechanical contractors will work on design plans to build and commission these systems. In conclusion, HVAC is a special unit that helps heat and cool homes and buildings. Making people's daily lives a lot easier, then it was when my grandparents were growing up, because they went from having to raise the windows to let the air in, to just having to push a button. Which is the easiest way to live in my opinion.