Ben Gurion University researchers have developed a 'green' window that saves energy both in winter and summer

In the "Window of the Seasons", there is a special mode for the winter season (heating) and for the summer season (prevention of warming), will save energy both in residential houses and in office buildings

Ben-Gurion University researchers have developed a window based on a glazing system that changes its properties according to the seasons, by rotating the glazing by one hundred and eighty degrees. The "Window of the Seasons", in which there is a special mode for the winter season (heating) and the summer season (prevention of warming), will save energy in both residential homes and office buildings.

The window was developed by Prof. Yair Etzion and Prof. Avitar Arel from the Desert Architecture Unit at the Blaustein Desert Research Institute on the Ben-Gurion University campus in Sde Boker, as part of a multinational development project in which the European Union is a partner, which invested about 600 euros. Later, he teamed up with the university researchers and the industrialists of the 'Alobin' company, which has extensive experience in designing and executing aluminum-based glazing systems, to provide a passive ecological solution that is cheap to manufacture and simple to assemble.

In the special window, which seeks to satisfy the desire for transparency without compromising on energy efficiency, the designers conceived a revolutionary window, literally: it can be turned from winter mode to summer mode by turning. The new window reduces the visual glare created as a result of the combination of large windows - which are needed for solar heating in the winter, stops the fading of the objects in the space as a result of direct sunlight hitting them and reduces the effect of "sunspots" that are created in the space where direct sunlight hits the occupants of the space and gives them a very warm feeling not comfortable

The system consists of two parallel glazing panels, which are installed at a small distance from each other. One panel is normal transparent (or insulating) glazing that enables the sealing of the space - as in any other glazing system. The second panel is a panel of "dark" glass, which transmits only a part of the sun's radiation, and at the same time absorbs another significant part of it and heats up in the process. This panel is usually darker than the normal panel and acts as "sunglasses" on the window. The degree of darkness of this glass is determined according to the planner's considerations, taking into account the conditions of the place where the window is installed. At the bottom of the dark glass and at the top is a narrow gap, which allows air to penetrate into the space between the two glazing panels and move between them. This entire glazing system is contained in a frame that rotates at one hundred and eighty degrees on a vertical axis within the fixed window frame.

As for the winter season, Prof. Etzion explains, the dark glazing is directed to the inside of the space, the transparent glazing is directed to the outside. "Short-wave solar radiation penetrates through the transparent glazing and damages the dark glazing. The latter heats up and emits long-wave radiation in two directions: to the space (similar to an existing electric radiator) which it heats, and to the transparent glazing, which blocks it and does not allow it to be emitted outside. The greenhouse effect - remember? Because of the high temperature of the absorbent glazing, an air flow is created between the glass panels - air from the heated space enters through the lower opening, heats up, rises in the gap between the glasses and is discharged - hotter - into the same space through the upper opening. The result - heating with long-wave radiation (harmless!) and convection, lowering the light intensity and preventing glare and glare. Direct radiation from the sun also cannot harm a person in space... Enjoy all the benefits of heating with the help of solar radiation, get rid of all the 'side effects'."

His development colleague, Prof. Aral, explains how the window works in the summer season: the dark glazing faces outwards, the transparent glazing faces inwards. The short solar radiation hits the dark glazing, from which long-wave radiation is projected out (from which we get rid of...) and towards the transparent glazing, where it is almost completely blocked. Outside air penetrates into the space between the glazing panels, absorbs heat from both panels, and is expelled outside. The dark glazing also allows less light to enter the space. There is no need for a shutter, the opening is exposed, the view is visible through it and the light intensity in the space is at the required level!

The 'Window of the Seasons' is, as mentioned, a perfect solution for the entrances of private houses and public buildings. "Installing the 'window of the seasons' in apartments, villas and projects will improve the natural air conditioning in the building, will make the spaces more pleasant by preventing glare and heat in the summer and heating in the winter, will reduce the costs of artificial heating and cooling and will help us all to protect our planet", say the researchers.