Advanced multi-function windows for the 21st century

“Fortochka”. A name, a Russian word for a ventilation-window, chosen to emphasize the synthesis of old and new, and the importance of air supply as an original purpose for windows.

Advanced windows are being developed in several avant-garde institutions and companies around the world. These windows are often described as “multi-function” windows because they include features that allow the user to adjust many properties that are often not available, or limited, in ordinary windows. Sometimes the term double-facade window is used, and other terminology is common, so there is confusion, and therefore it is necessary with a definition here. But first a little history.

Glass was used very sparingly in buildings before the 16th century, but was common by the 19th century. The advantage of double windows for warmth is obvious, and such double windows were used in The North when resources were available. The invention of sealed double glazing units in the middle of the 19th century permitted single windows with double glazing, allowing some of the thermal advantages of double windows at a cheaper price. Such windows became standard during the second half of the 20th century, and recent developments with thin, invisible, metallic coatings and insulating gas fillings have made the product even better, technically.

However, problems with durability (lifetimes of average 20 years) and insufficient fresh air (high incidences of asthma and allergy in such homes) stimulated product development, and at the start of the 21st century, a new type of double window is appearing, combining the advantages of the old type of windows with the technology of the newer types.

The specific physical feature of such windows is an outer frame with single glass, to provide basic weather protection, and an inner frame with high performance double-glazing to provide climatic protection. In both the inside and outside window frames are several smaller windows that can be opened, some near the top and some near the bottom of the window. The design can be of many types.

The air space between the two frames provides a climatic buffer zone, a space which is climatically somewhere between the outside and inside temperature, a space which eliminates wind gusts and limits particles of soot or pollen etc. from entering the indoor climate. Additional features such as solar shading, energy absorbers, moisture removers and noise absorbent panels can be added in this air space.

The result of having several layers of climatic protection, all of which can be adjusted by the user, is that the user is provided with many combinations of features, and this window can therefore respond to all forms of weather. This can be compared with people selecting their clothing according to the weather.

Such windows can be adjusted to give people the light quality they require, fresh air without drafts and with passive heat recovery, sound reduction (even while providing air), protection from the sun, condensation removal, and excellent durability and economic value.

The main point to remember is that none of these features of the “Fortochka” window are pre-set or fixed, but can be adjusted to suit the weather, the situation, and the mood: dark, tight and muffled protection when people have the humour of a “Dostoyevsky” character, light, breezy and open when one might feel the need for a “Lermontov” escape, or anything in between, as you like it. The choice is with the user, not with the producer or designer.

A variant of the multi-function window is the “intelligent” type, where the window is fitted with small hidden motors, sensors and communication devices, so that it can respond to telephone requests or to pre-set requirements to automatically limit over-heating or to avoid high indoor moisture levels.

An obvious but neglected feature is electric lighting, which can be built into the window so that daylight and electric light come from the same, natural, direction.

An item of general interest, but of specific importance to a building like the Hermitage, is that security and comfort can also become synthesized with the design of double windows, because the offset openings permit air movement but are impossible for entry.

Additionally, of course, it is natural to include movement sensors in such advanced windows, both for security alarms on movement from the outside, or for activating communication devices, such as security cameras or loudspeakers.

Once the window is fitted with sensors, a detection device for smoke or heat, or other fire alarm system, would be appropriate, and windows with loudspeakers could inform the public of exit routes.

From the above it is clear that we are on a futuristic journey, but a journey against the tide, for modern buildings include many of the above functions all cluttered and clumsily installed by a whole host of different trades and specialists, whereas a window with all the above functions is easy to install, requiring just an electrical connection.

A futuristic journey already indicated, perhaps best, if we can avoid the political implications, in Evgeny Zemyatin’s “We” from 1922, where glass was everywhere, and “big brother” too. The opposite end of the futuristic spectrum, regarding climatic control of buildings, was sketched by E.M. Forster in 1910, with his short story “The Machine Stops”. So are we now on a futuristic journey, which would take civilization forwards? A journey based on a synthesis of the best knowledge from the past, and the best of modern science and technology?

It is unfortunately disturbing to note that the futuristic journey we are currently on regarding “modern” windows is a journey backwards for civilization. Many “modern” windows, including many of those sold in St. Petersburg in 2004, are actually colder, unhealthier, and darker than the old windows they replace. They are also too tight and inflexible, without possibility for fine adjustment of the air supply, so that there are usually just two possibilities—too little air, or too much air.

Therefore the risk of moisture problems in houses that change their windows is high, a common problem of North European development from the 1970s onward, receiving much research attention now. But unfortunately this knowledge is not being presented in Russia together with the marketing material for “modern” (old) European window technology. So, please, Russia, do not import the mistakes of the West in this field!

And the paradox: better windows, based on the best of the old and the best of the new are available. Also, often, it is possible; warmer, prettier and healthier, to upgrade existing windows with advanced attachments, at a considerably cheaper price than the “modern” windows that dominate the market.

But there is a strange barrier to such advanced windows: International product standards. Because these standards have not considered product development, and therefore, for example, there are no methods for calculating the thermal balance of “Fortochka” double windows that allow air movement between the glass layers. It is clear, and measurable, that air is warmed on its way into the room by the heat coming through the inner window. But there is no factor in the standards to describe this scientific feature. Strange, but true.

More food for thought: the futuristic Fortochka multi-function window is a product based on scientific principles developed centuries ago. It was a surprise, for me, in 1998, to identify the basic scientific principles of such “advanced” windows in The State Hermitage Museum and other places in St. Petersburg.

But perhaps this should not be a surprise, because it was here in Russia, in St. Petersburg, in 1726–1732 that the mathematician Daniel Bernoulli discovered and described the principles of the 2nd law of thermodynamics, where the forces that describe the natural air movement in such a window were first scientifically developed.

Did Bernoulli talk to his contemporary, the Winter Palace architect, Bartolomeo Francesco Rastrelli, who became one of Peter the Great’s court architects in 1722? Perhaps we will never know, but Bernoulli and Rastrelli were the same age (both born in 1700) and it is possible that they exchanged ideas in that age of enlightenment. Rastrelli certainly utilized these basic forces of nature, of air movement, for the first time, to my knowledge, in a building.

This is therefore the explanation for the choice of name to describe these types of advanced windows, using the Russian word for a ventilation window, Fortochka. A symbol for using the past, which, together with selective application of quality modern technology, shows a way for moving forward, a possibility for a 21st century renaissance.

Sergio Fox