Problems of energy efficient glazing

Abstract

Problemsof heat-shielding windowapertures are discussed.The new heat-saving requirements and the ways ofsolving the problemusing heat-saving glazingare specified.State-of-the-art types of glass and glazing units are decribed.Since the moment when the area of glazing in some buildings began to compete with the area of the walls and in other buildings entire walls were made of glass, the requirements imposed on the properties of glass were modified and expanded. Indeed, most of the functions now fulfilled by glazing (the formation of the microclimate and hygienic environment of the interior) were previously executed by the walls. The significance of creating the interior microclimate can be defined in the following way: "The microclimate in public and residential buildings is the most important parameter ofcomfort and one ofthe crucial factors in increasing human life expectancy" [1].There are no doubts that the problems of providing a comfortable environment for the interiors of buildings are going to receive much attention. The most important problems concerning this are: the prevention of temperature fluctuations on the internal surface ofthe glass in winter (prevention of negative radiation directed to the glass), improvement of lighting conditions, improvement of the sound-insulating properties of the glass, and reduction of heat losses occurring through the glass.It is logical that along with the introduction of engineering methods for microclimate control in buildings, new types of glass with special properties will find wide application. The variety of these types ofglass increases and their share in the total volume ofglass production will keep growing.Each type ofglass possesses its own set of properties and has its own area of application. The knowledge of the properties of different types of glass used in construction ought to be the key to understanding its function in glazing. This is one of the main factors in selecting a type of glass for the windows of a particular building. The other factor is to for-1 "GIS" joint stock company. Moscow. Russia. 3 mulate correctly the requirements for glass structures and materials.The most important functions fulfilled by windows are as follows: provide for penetration of light, reduce heat losses in cold seasons, protect the rooms from outside heat in the summer under intense insulation; protect the interior from penetration of noise, dust, and outside air. In designing windows one should integrally solve all these problems, and the solutions in tum depend on the selection ofthe glass structure and the type ofthe glass used.It ought to be noted that the architectural and construction requirements imposed on windows as an element of the building are traditional and in many cases outdated. The structure and outward appearance of contemporary buildings (rectangular spaces, lighting implemented mostly via vertical apertures, extremely rare use of upper lighting etc.) were formed at the border of the XIX and XX centuries. At present, energy problems have altered the v...

Análisis del desempeño térmico de los sistemas constructivos de un edificio de oficinas mediante simulaciones dinámicas

“…Actualmente existe gran variedad de tipos de cristales, con propiedades ópticas muy diferentes, que permiten seleccionar los más adecuados al tipo de aplicación requerida. El conocimiento de las propiedades térmicas y ópticas será clave para el entendimiento y selección del tipo de cristal adecuado para cierta edificación (Orlov et al, 1998). Baetens et al (2010) concluyen de una revisión de literatura que las ventanas electrocrómicas son las más prometedoras comercialmente, ya que pueden reducir hasta 26% el consumo de energía requerida para iluminación, y hasta 20% el consumo energético por refrigeración cuando se utilizan en climas cálidos.…”