The glass buildings They are increasingly widespread in the big cities of the world, from New York to Dubai and Shanghai. This, although it does not have properly structural functions, participates as a protagonist in the global energy balance of a building. Therefore it arises spontaneously to ask, regardless of the design, if this type of buildings may be able to combine aesthetic and energy efficiency at the same time. In this article we discuss the problems e Project strategies to be put in place to obtain buildings with energy -effective and competitive glass surfaces with traditional wrapping systems.
The efficiency of glass buildings from an energy point of view
The glass buildings fascinate: they reflect the sky and give natural light to the rooms. But without proper design they can become significantly energetic. In fact, in an era in which environmental awareness is crucial, sustainable construction It is nowadays the fundamental paradigm for the reduction of the negative impact of our activities on the environment. The glass, by its nature, is a material transparent in sunlight:
- Allows you to reduce the need for artificial lighting during the day;
- Favors the natural heating of the internal environmentstaking advantage of the so -called passive solar gain.
Seen from this perspective, it would therefore seem an optimal solution. However, internal thermal comfort must be analyzed by understanding what happens when temperatures they begin to climb or lower.
Summer and winter: the double problem
By hitting a glass surface, sun radiation crosses and warms the internal environments; Once stored, the radiation is absorbed by surfaces and people and re -read in the form of heat. The glass, however, retains part of this heat, preventing its dispersion. Result:
- In summer the glass surfaces increase the overheating of the building and, consequently Consumption for air conditioning. It is the same mechanism that makes the agricultural greenhouses work, or that maintains the foods exposed in the boys of the bars;
- In winter, however, the problem overturns. Even if the windows allow the entry of the sun’s rays and therefore a certain Free thermal gainOverall, the energy balance often remains negative. The reason is simple: the glass has one thermal transmittance Much higher than other building materials, such as isolated walls. In other words, The internal heat tends to disperse much more easily through the glass surfacesespecially at night or cloudy days, when there is no sun to compensate.
This means that to maintain a comfortable temperature inside a glazed building during the winter, it is necessary to consume much more energy for heatingwith a consequent Increase in the environmental impact. The larger glass surfaces, the greater the amount of energy necessary to compensate for these dispersions.
The possible solutions to the heating problem in glass buildings
To create buildings with large window surfaces that are truly efficient and low environmental impact, it is essential to join intelligent bioclimatic design And Advanced construction technologies. There Bioclimatic design consists in designing the building in harmony with the local climatetaking advantage of natural resources as much as possible (sun, wind, shadow … Even the vegetation present or create other ad-hocif it were not enough) to ensure thermal comfort and reduce energy consumption. Here are therefore the main innovative solutions and materials used today:
- High performance glass: Like triple low emissives, glass with insulating gases (Argon, Krypton) or chromogenic technologies, capable of reducing thermal dispersions in winter and solar gain in the summer;
- Natural ventilation systems: designed to take advantage of air currents and natural convective motions, reducing the need for air conditioning;
- Intelligent platforms that automatically manage temperature, light, shields and ventilation to optimize consumption;
- Integrated facades with photovoltaic panels: which transform transparent surfaces into energy generators;
- “Intelligent” dynamic glass: capable of varying transparency and opacity in real time to control light and heat, without manual intervention.
An application of these technologies is the Unicredit Tower in Milandesigned with curved and reflective glass facades, with highly thermal high performance glass, integration of solar panels on the roof e Photovoltaic films on external windowsall assisted by automated systems that regulate temperature and humidity.
Research is revolutionizing the role of glass: no longer just a passive element, but A material that produces energy, regulates light and actively participates in the sustainability of the building.
