Upcoming seminar

Heat-, fire- and engine-driven mechanical ventilation!
November 9, 2016

Heat-, fire- and engine-driven mechanical ventilation!

History of ventilation: heat and fire driven!

Ventilation technology has a long history and has gradually developed alongside the changes brought about by the evolution of industries and buildings as well as changes in our personal needs. Read more about what does the word “ventilation” means “Ventilation, ventilatio, ventus! Vind, loft, luft!” (link here). Before engines were used for mechanical ventilation, heat and fire were used for driving the ventilation.

Heat-driven ventilation

Before steam engines and electricity made it possible to run fans efficiently, airing was often the only available ventilation solution for buildings. However, there was always a certain flow of air through the chimneys thanks to the so-called stack effect. The principle is simple – warm, less-dense air will rise up through a building, creating an under-pressure at the lower levels, thus drawing in fresh outdoor air through any openings, intentional or not. Heating offered free ventilation and this became known as heat-driven ventilation. Until the middle of the 1900s, airing and heat-driven ventilation systems were often sufficient for use in housing. However, in other types of buildings, such as schools, hospitals, industrial plants, prisons etc. they were often inadequate. Consequently, nearly all aspects of modern ventilation technology were originally developed to meet the needs of non-residential buildings. It was only later that advanced solutions were adapted for housing. Read more about the health and Air we breathe in homes! (link here).

Fire-driven ventilation

During the 1800s, technical developments were made in which fire was the main driving force for creating air flows in buildings. In other words, ventilation was still based on the same basic principles as used in medieval mines. However, in comparison to mines, buildings required considerably more sophisticated solutions, not least to introduce air into spaces without causing discomfort. This type of ventilation was known as fire-driven ventilation. Manually-driven wooden fans and bellows had already been used in a few buildings in the middle of the 1700s but these solutions had an obvious disadvantage: they required a great deal of manpower. For example, two men were required to operate the ventilation for Queen Victoria’s box at the opera in London.

Man-powered and engine-drive mechanical ventilation

If water power was available, which was primarily the case in spinning mills, it was also used to its full advantage to power fans. Otherwise, there were few good alternatives to heat- and fire-driven ventilation or to man-powered mechanical ventilation, despite ingenious attempts to use falling weights, tensioned steel springs and other devices as sources of power. By the time steam engine-driven mechanical ventilation made its breakthrough during the second half of the 1800s, the fire-driven technology had been refined to such an extent that both the flow of the air and its temperature could be regulated. There were also solutions in which the air could be purified and humidified before it was drawn into a building. However, as the fire-driven technology was susceptible to imbalances it was used almost exclusively in special buildings or in laboratories.