Air conditioning systems are those that allow the temperature of objects or isolated spaces to be modified, to improve comfort and conservation. In this sense, air conditioning systems allow us to condition the temperature of spaces to improve the comfort of people; in addition, also preserve food and products for long periods of time.
In this article, we will talk a little about the history and evolution of the air conditioning sector in the world.
Air conditioning systems using mixtures of substances
Since ancient times, the Chinese have known that a mixture of ice (water) and salt (sodium chloride) could lower the temperature of the mixture by several degrees, below 0° Celsius.
In 1715, the Fahrenheit scientist established the “zero” of his temperature scale, using a mixture of ice, water and ammonium chloride. This mixture creates a temperature of approximately -18° C. On the other hand, Von Braun managed to freeze mercury to -40° C, with a similar refrigerant mixture, in the year 1760.
These procedures are nothing like modern industrial air conditioning and refrigeration systems. However, they were the first methods that allowed the temperature to be lowered artificially, but in a very limited way compared to the current ones.
Air conditioning systems through evaporation of volatile substances
It is very important to highlight what William Cullen‘s experiment meant in 1750. This experiment was one of the empirical bases of the laws of thermodynamics, which are the basis of industrial, commercial and domestic refrigeration.
Cullen used in his experiment a vacuum chamber, with its respective vacuum pump. Inside the chamber he placed a container with water, at a temperature of 6 degrees Celsius. In turn, inside the container with water, he placed a container with nitrous ether in liquid state. Then, he applied a vacuum to the chamber so that the nitrous ether boiled at 6° Celsius. Boiling the ether cooled the water, which in a few minutes froze. That is, the vaporized ether absorbed the temperature of the water until it was frozen.
Air conditioning systems of closed cycle of volatile substances
William Cullen’s method did not reach the air conditioning market, and only stayed in the laboratory. However, the American Jacob Perkins patented a machine that did have practical and commercial uses, in 1834.
In the Perkins engine, ether was boiled in an evaporator under conditions of low pressure and temperature. In turn, the evaporator (heat exchanger) absorbed heat from the water and froze it. The ether vapor was then collected, compressed, and condensed, at higher pressure and temperature. Finally, the liquid ether was reintroduced to the evaporator, through an expansion valve; this allowed to lower the pressure and temperature of the ether, again. Everything worked in a continuous cycle.
This old machine was the closest thing to current industrial and commercial air conditioning systems. The air conditioning market in Europe and the USA used the principles of this machine to produce ice in significant quantities. For more than forty years, this industrial air conditioning system was perfected, thanks to the work of great engineers.
It should be noted that the machines of the time were inspired by James Watt’s steam engine, developed in 1769. It worked by taking energy from the combustion of coal, which heated the water in the boilers to produce high-pressure steam. Then, the pressurized steam generated the movement or driving force of the machine. The energy efficiency of the steam engine was very low, but it was the engine of the Industrial Revolution, all over the world.
The ether gave way to air conditioning systems based on ammonia and carbon dioxide (CO2). These refrigerant substances provided better thermodynamic characteristics to the industrial and commercial air conditioning sector.
Industrial air conditioning by ammonia absorption
Joseph Priestley discovered ammonia (NH3) in 1774. In addition, he noted how easily and quickly water absorbed ammonia. This affinity of ammonia for water was key for the French inventor Ferdinand Carré to develop his water cooling machine in 1859.
Carré’s machine was composed of two parts or airtight containers. The first container contained an aqueous solution of concentrated ammonia. This part acted as a heater and then as an ammonia absorber. On the other hand, the second vessel functioned as a heat exchanger, condenser and evaporator.
Carré’s machine worked in two stages. In the first stage, the first container with the aqueous ammonia solution was heated. With the heat, the ammonia separated from the water and was released under pressure into the second container, where it condensed or liquefied. Then, the heating of the first container was stopped and the pressure of the system was lowered. The liquid ammonia in the second container would then start to evaporate due to the lower pressure, and it would get very cold. Finally, the water, placed in the heat exchanger of the second container, froze completely in about 20 minutes.
All the ammonia returned to the first container and quickly mixed with the water. In this way, a cooling cycle was completed. Carré made a machine for intermittent operation and another for continuous work. The continuous operation was much more complex than the intermittent one, but it produced more ice.
With this machine, the technological feat of transporting meat from Argentina to France, on the ship “Paraguay”, was achieved in 1875. Ferdinand Carré was the initiator of practical industrial refrigeration, using ammonia as a refrigerant.
Industrial and commercial refrigeration in the 20th century
A principios del siglo XX, ya el desarrollo de los motores de combustión interna y el motor eléctrico se imponían y desplazaban totalmente a las máquinas de vapor. El sector de la climatización recibió un fuerte impulso, con el empleo de medios más eficaces y de mejor rendimiento. Esto permitió ampliar el mercado de la climatización industrial en todo el mundo.
En 1930, Thomas Midgley, mientras trabajaba para la empresa Dupont, anuncia al mundo el nuevo refrigerante sintético, que revolucionó la refrigeración industrial y comercial en todo el mundo. Este refrigerante es el Freón-12, el cual es una sustancia de la familia de los fluorocarbonos. En muy poco tiempo, el Freón-12 desplazó al amoníaco y al CO2, debido a sus excelentes propiedades termodinámicas y a su baja toxicidad.
Para el año 1920, aparecieron los primeros compresores de refrigeración eléctricos. Este desarrollo permitió la aparición del primer aire acondicionado doméstico, en el año 1958. Los sistemas de climatización con base a Freón-12 y los compresores eléctricos permitieron ampliar el mercado de la climatización a los pequeños comercios y hogares.
Todo iba bien con el Freón-12 hasta que en 1987, en el Protocolo de Montreal, los países de todo el mundo firmaron el acuerdo para sustituir los refrigerantes a base de clorofluorocarbonos. Estaba demostrado que estas sustancias son perjudiciales para la capa de ozono de la atmósfera. Ante esta situación, el mundo ha buscado otras alternativas menos dañinas al medio ambiente.
At the beginning of the 20th century, the development of internal combustion engines and the electric motor were already imposing themselves and completely displacing steam engines. The air conditioning sector received a strong boost, with the use of more efficient and better performing means. This made it possible to expand the market for industrial air conditioning throughout the world.
In 1930, Thomas Midgley, while working for the Dupont company, announced to the world the new synthetic refrigerant, which revolutionized industrial and commercial refrigeration throughout the world. This refrigerant is Freon-12, which is a substance from the fluorocarbon family. In a very short time, Freon-12 displaced ammonia and CO2, due to its excellent thermodynamic properties and low toxicity.
By 1920, the first electric refrigeration compressors appeared. This development allowed the appearance of the first domestic air conditioning, in 1958. Air conditioning systems based on Freon-12 and electric compressors made it possible to expand the air conditioning market to small businesses and homes.
Everything was going well with Freon-12 until in 1987, in the Montreal Protocol, countries around the world signed the agreement to replace chlorofluorocarbon-based refrigerants. It was shown that these substances are harmful to the ozone layer of the atmosphere. Faced with this situation, the world has sought other alternatives that are less harmful to the environment.
Intersam, expert company in industrial and commercial refrigeration
With regard to industrial air conditioning and refrigeration systems, Intersam is a company that is a reference throughout Spain, thanks to its experience and professionalism. In addition, at Intersam we manufacture the heat exchanger you need, tailored to the needs of your business. If you have any questions or need information, contact us and we will be happy to assist you.