Iluminación natural diseñada a través de la arquitecturaAnálisis lumínico y térmico en base climática de estrategias arquitectónicas de iluminación natural.

Abstract

Daylighting design today continues to pose major difficulties due to the high number of variables involved. The solutions adopted are also dependent on architectural design decisions regarding final forms and materials which are in turn affected by numerous other factors. Essentially, the amount of daylight in a building depends on the nature of its spaces and openings, its surrounding environment and its use of elements providing protection against direct sunlight. These same key factors also affect the amount of solar radiation entering the building‘s spaces and the resulting thermal conditions. During the course of the 20th century, architectural practice and the science of daylighting largely evolved in parallel and, with only rare exceptions, progressed quite separately. This led to a schism between Architecture and Daylighting: units of measurement were standardized and metrics, models and calculation methods for daylight were developed but these played hardly any role in the process of architectural creation. Today, at least in Spain, architects are generally unfamiliar with how daylight conditions are calculated for the spaces they design, and do not fully understand the metrics that quantify and express the light levels obtained. Daylight is neglected in architectural planning and buildings are designed without taking into account how the decisions taken affect the interior light environment, partly because architects are simply unaware of their impact. Such a lack of information has made the creation of well-daylit buildings more of an art than a science, with architects relying more on intuition and previous experience than on the study of objective, scientific measurements and metrics of daylight and sunlight in interior spaces. The situation is aggravated by ever-increasing pressure to meet greenhouse gas emission objectives, a consideration that has generated greater demands to reduce energy consumption in buildings – in part by cutting down on the energy needed by the buildings themselves. In the absence of detailed legislation regarding natural light, the need to comply with an ever-growing number of building regulations has pushed daylighting considerations into the background. Because of the importance currently attached to energy efficiency in buildings, architects tend to show more interest in daylight as a means of regulating thermal conditions than as a source of natural illumination. But although exploiting daylight can help reduce electric lighting costs, it can also contribute to overheating, resulting in higher energy consumption in cooling. It should also be pointed out that when the impact of global solar radiation on interior environments is studied in building construction, its heat and light components are invariably considered quite separately: integral analysis of the effects of solar radiation is conspicuous by its absence. Any evaluation of how daylight can impact a building should also take into account its thermal effects. Direct solar radiation entering a space through windows or semi-transparent elements is known as solar heat gain. But in daylighting design, that same radiation is known as insolation. Insolation therefore encompasses both the thermal and lighting-related aspects of the direct solar radiation entering a space.