New concepts for daylighting and heating of buildings

In traditional architecture, opaque elements having thermal insulation properties are used with transparent elements which allow for visual contact, daylighting, and passive solar heat gain. Dividing up the available area into opaque and transparent parts requires a compromise between maximizing the possible daylighting and solar heat gain capabilities and minimizing the loss in thermal comfort through the raeltively high heat loss of conventional glazings. The use of recently developed transprarent insulation material (TIM) may influence future architecture. When comparing new TIM-structures with double glazings, their heat loss coefficient can be reduced by a factor of 3 - 5, while having the same transparency. As a result, transparent elements can now be realized with high daylight and solar heat gain capabilities, but with thermal comfort similar to walls. However, the nature of these structures allow only for diffuse transparency, so that conventional glazings for visual contact w ill still be necessary. As a consequence, these two types of transparent elements can be combined in such a way that the TIM structural area is selected according to the need for daylighting and instantaneous solar heat gain, and the conventional glazings are selected to suit the need for visual contact only. A second application of TIM is for the transparent insulation of walls. This allows the total facade of a building to be turned into a solar collector. The thermal storage capacity of the wall buffers the solar heat gain and provides uniform room temperatures with improved thermal comfort. Since these high efficient elements can produce surplus light and heat, energy flux is controlled with automatic roller blinds. As a result, the facade becomes intelligent, reacting on external weather conditions in such a way that optimum comfort for the inhabitants is obtained.