Lawrence Berkeley National Laboratory

This paper discusses the effect of a new skylight prototype on the energy and environmental performance of an office building. It has been considered as a priority the study of the factors that relate daylighting and energy, as well as, to a certain extent, other aspects such as ventilation and insulation. Many architectural designs are presented as correct if the thermal requirements alone are met, even at the risk of later energy waste in lighting devices and visual or physical discomfort. On the other hand, large glazed areas allow more daylight into a space, but they may also allow excessive heat gains or losses which increase the air-conditioning cooling or heating load. To avoid these problems, we have considered the combined effect of daylight and energy from the beginning of the skylight design-process. The environmental analysis tool Ecotect has been used together with a daylighting software based on configuration factors that we have used in former PLEA conferences to study the problems of direct sun over architectural structures. This question can not be treated adequately with conventional programs for overcast skies. The skylights have already been constructed and on-site measurements in the offices have been taken to complement the computer simulations data. The results show that it is possible to achieve energy saving and high daylight levels in winter without increasing heat loads during the summer.