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We’re all familiar with modern HVAC, but when did it start? How did it develop? Who ‘invented’ HVAC? We decided to look into the history of HVAC, so this month we begin a series of articles to try and answer these questions.

HVAC in Pre-History

Some form of HVAC has been around since man first walked the earth. Pre-historic man can be credited for the first heating systems by lighting fires in their caves. During the last ice-age, they also discovered that by digging down into the permafrost layer, they could keep foods chilled and preserved for the harsh winters. We can look at that as the first attempts at geo-cooling. They also developed methods to force draft fires so that they would burn bone to heat their dwellings. Around 3000 BCE (Before Common Era) the furnace was developed for metal working.

Classical Times

The Egyptians are known for inventing many ‘modern’ conveniences and air-conditioning is one such invention. They discovered that hanging wet reeds in windows cooled the air that blew naturally into rooms. This was the first water-cooled air-conditioning.

The first recorded use of underfloor heating was around 1400 years ago when it was used in the palace of King Arzawa in Beycesutan, in Anatolia in modern dayTurkey. Fires were lit under floors to heat the rooms above.

The Greeks developed the idea of aqueducts which provided water to entire cities and were the basis for cooling/heating water pipe systems. The Romans took this a step further and built homes and bath houses with vents or ducts under the floors to pipe in hot or cool air. This was known as the hypercaust. The Chinese learnt that moving air over the skin gave a temporary cooling effect and are credited with inventing the fan. The forerunner of modern air conditioning fans.

In the Middle East with its scorching temperatures, it was learned that as hot air rises, towers would draw in cool air and expel hot air. So, cooling towers were born.  This concept has changed over the years but the idea of cooling towers with air ducts is still in use.

The Middle Ages

In the 8th to 15th Centuries, in colder northern European countries, the idea of a central hearth or fireplace came into common use. This led to a lot of smoke in the dwelling which had to be removed thereby losing heat. This led to the development of the chimney. The earliest written account of the use of a chimney is found in 1347 from Italy.

Louis Savot is credited with the introduction of the fireplace grate, which allowed more air to reach the fuel and more heat to be generated. He also developed rules for proportioning the size of a fireplace and designed a jacketed fireplace that allowed air to circulate around the fireplace, heating it in the process. Cold room air entered at the bottom of the fireplace where it was warmed and entered the room through openings above the mantle. In England, a duct from the outside was added to provide air for combustion.

HVAC in the Early Modern ERA

In 1550 Blas Villafranca, a Spanish doctor based in Rome developed a method of cooling wine by mixing salts with water. The first example of cooling by chemical process. Around the same time, in 1556 Georgius Agricola published a book called De Re Metallica, describing ventilation of mines in Saxony and Brittany by manually operated circular fans and fires at the base.

Up to this point, humans found various methods to heat and cool, but had no means of measuring temperatures. In 1624 The word thermometer first appears in literature in a book by J. Leurechon, La Recreation Mathematique. A few years later in 1631 Rey proposed a liquid thermometer using water.

The invention of the thermometer is attributed to Galileo Galilei (1564-1642), however, the first attempt at quantifying temperature appears to be that of Heron of Alexandria in the second century AD, who invented a glass instrument containing a column of water that was displaced in proportion to the heat applied. By the mid-17th century alcohol thermometers were known in Florence.

Historically, heating and cooling appear to have been developed for human comfort but around 1653 to 1660 Sir Hugh Platt proposed the use of hot water for the drying process in gunpowder manufacture. Heating in industry was born

By this stage, scientific research in various fields, including heating and cooling was really taking off.  In 1657 The Accademia del Cimento, in Florence, used refrigerant mixtures in scientific research, as did Robert Boyle in 1662.  Robert Boyle also established the laws linking pressure and volume of a gas at a constant temperature which was verified experimentally by Mariotte in 1676 giving us the physical laws that govern HVAC today.

In 1715 Gabriel Daniel Fahrenheit developed the mercury thermometer, followed by the development of the Centigrade Temperature Scale, later renamed the Celsius Temperature Scale in honour of Anders Celsius who invented it in 1743. In 1736, Dr John Desaguliers introduced a hand operated fanning system to ventilate the House of Commons. Obviously even in those days, politicians were full of hot air!

Benjamin Franklin invented the cast iron Franklin stove in 1742. The Franklin stove is a metal-lined fireplace with a hollow baffle near the rear and relied on an “inverted siphon” to draw the fire’s hot fumes around the baffle thereby transferring more heat from the fire to a room’s air. It was intended to produce more heat and less smoke than an ordinary open fireplace, but it only achieved success with improvements to the smoke extraction by David Rittenhouse.

Cooling was enjoying major attention and in 1755 William Cullen of Glasgow, Scotland produced cold from fluids evaporated by a vacuum pump. In the same year Hoell noted that compressing air and allowing it to expand in a cylinder caused cooling. Three years later in 1758 Rev. Stephen Hales published A Treatise on Ventilators.  His main concern was with ventilation on ships by using inject/exhaust pumps like blacksmith bellows.

In 1760 Von Braun, in Petersburg, froze mercury, using a refrigerant mixture and in 1766 John Blakey introduced the first water tube boiler. A great step forward in HVAC was in 1774, when Joseph Priestley isolated ammonia and noticed its great affinity for water. In 1777 another industrial use for hot water was found when M. Bonneman first used hot water to thermostatically heat an incubator for hatching chickens.

Moving on

As you can see from the above, as time passed, discoveries and innovations were increasing rapidly. In this article we have covered from the dawn of time to around the end of the 18th century. Next month we’ll find out about more of the evolution of HVAC into modern times.