History of an air conditioner

The people who created Cooler mechanism (History of an air conditioner)

The commercial use of the air conditioner, the predecessor of coolers, began about 10 years after the sales of electric fans began. One of the basic principles is an experiment done by Benjamin Franklin (1706-1790), who is known as an American inventor, scientist, and politician, and John Hadley (1731-1762) at the University of Cambridge, England.  Franklin is also famous for conducting electrical studies, proving that lightning is an electrical phenomenon, and devising a lightning rod in 1749. In 1758 he has done two experiments to rapidly cool an object using the principle of evaporation (heat of evaporation). He then tried to evaporate a highly volatile liquid, such as alcohol, and discovered that ether could cool an object to below freezing. Franklin concludes that humans could be frozen to death on warm summer days.

Then in 1820, British chemist and physicist Michael Faraday (1791-1867) discovered that vaporizing liquefied ammonia by compression could cool the surrounding air. In addition to this, Faraday had considered one of the most influential scientists in the history of science, contributing to the fields of electromagnetics and electrochemistry, including "Faraday's Law of Electromagnetic Induction".

Thirty years after the discovery of Faraday, John Gory (1802-1855), a Florida (USA) doctor uses a compression-type ice machine to make ice and chill the patient's room in his hospital for the patient. He did this because the general theory is that bad air causes illness. He had the idea of controlling the temperature of the whole building, the whole city, and controlling the air conditioning centrally, but it didn't work. However, in 1851, Gory got a patent for the ice machine.

It was an American engineer and inventor Willis Havilland Career (1876-1950) who invented the modern cooler. After graduating from the Department of Electrical Engineering at Kernel University, he joined Buffalo Forge, one of the three largest fan makers in the United States, in 1901.

In 1902, the job of humidity control at the Sackett Wilhelms printing plant in New York was brought to him. The printing factory at that time started multicolor printing, and the change in humidity in the room caused the paper to expand and contract, which made printing unsuccessful. The carrier's "electric air conditioner," which is required to keep the relative temperature inside the room constant, can control not only temperature but also humidity. By keeping the temperature and humidity low, the condition of the paper was kept constant and the ink adhered well. His invention has since contributed greatly to the development of air conditioning technology. 

After further improvement and field tests, in 1906, Carrier obtained a patent for its invention and introduced the world's first spray-type air conditioner (which can humidify and dehumidify by heating and cooling water) to the world.

In 1906, when the carrier was granted a patent, Stuart W. Crammer of America sought a way to add moisture to his textile factory. A combination of humidification and ventilation is used to control the humidity in the factory to achieve the optimum value. When he applied for a patent, he used the term "air conditioning" for the first time. This is the origin of the word "air conditioner" as mentioned above.

Air conditioners and refrigerators in the early days used toxic or flammable gases such as ammonia, chloromethane, and propane. If they leaked out, there was a risk of death. Against this backdrop, in 1928, American industrial chemist Thomas Midilly (1889–1944) was asked to research substances that would replace toxic and flammable refrigerants. Freon was developed. This refrigerant was safe for humans but later found to be harmful to the ozone layer.

Currently, specific CFCs and alternative CFCs are used, but it cannot be denied that they are the cause of ozone layer depletion and global warming. Although it is a necessary refrigerant for coolers and refrigerators, technological development in air conditioning technology continues to protect the global environment of the future.

  

Mechanism of cooler born from various researches and inventions

The cooler was born from the experiments, research, and inventions of these ancestors. It is a device called "heat exchanger", which is used for various industrial products such as boilers, steam generators, condensers, air conditioners, and vehicles. This is an equipment that transfers heat from a fluid with a high temperature to a fluid with low temperature by utilizing the property that heat flows from a location with a high temperature to a location with a low temperature. It is heated and cooled by moving and replacing.

The basis of how heat exchangers work is the nature of liquids and gases. When a liquid turns into a gas (evaporates), it absorbs heat from surrounding objects. The lower the evaporation temperature and the lower the pressure, the greater the heat absorption. On the contrary, heat is released when the gas turns into a liquid (condensation), but it is known that if cooled at high pressure, it is easy to condense and the heat radiation increases.

For example, after sweating in the summer, when you hit the air it feels very cool, and when you wipe your hands with alcohol, it is cool because water or liquid alcohol evaporates and takes a lot of heat from the surroundings when it becomes a gas.

Coolers use these properties of fluids to control room temperature which is called as air conditioner afterword.  An air conditioner consists of an indoor unit and an outdoor unit, and a fluid (refrigerant gas) circulates in the refrigerant pipe that connects them. When the fluid that became a low-temperature liquid in the decompressor of the outdoor unit enters the indoor unit, it becomes gas due to the heat inside the room. At this time, the heat of vaporization is generated. Cooled air is sent out from the indoor unit by removing the heat of the indoor air drawn by the fan. The vaporized fluid returns to the outdoor unit and becomes hot gas in the compressor. After that, when it passes through the heat exchanger of the outdoor unit, it is cooled by the fan and releases heat to the outside to return to liquid. The mechanism of the air conditioner (cooler) is that the liquid is sent to the indoor unit again.

Heating is the opposite of this, in which the heat of the outside air is absorbed and the refrigerant that has become a high-temperature gas in the compressor of the outdoor unit is sent to the indoor unit. The heat exchanger heated by the gas emits heat into the room with a fan. This creates a warm breeze from the indoor unit. Air heat in the room is sent to the outdoor unit by refrigerant gas and released to the outside. This circulation controls the temperature of the room.