Evaluating daylighting potential and energy efficiency in a classroom building

In this paper, we analyze the possibility of using daylight as the main source of light for learning and teaching activities in a classroom building of the Universidade Tecnologica Federal do Parana, in Curitiba, Brazil. Beginning with a survey on light bulb and luminaire types used in the building and on the potential of daylighting in such environments, six different classroom types with different solar orientations were selected for analysis. The research methods included the estimation of daylighting potential from obtained daylight coefficients (DCs) for periods of the year and sky conditions, other than those of the onsite measurements; the evaluation of conformity of the lighting system to the Brazilian RTQ Code (Regulamento Tecnico de Qualidade), an energy consumption rating system, aimed at reducing electric energy consumption in office buildings; the estimation of electric energy demand for a combined use of daylighting and lighting system; the proposal of an efficient lighting system; and cost assessment using payback analysis. Results suggest energy savings of up to 94% when integrating daylight with the artificial lighting system, a payback within the range of 22-60 months for a complete substitution of the existing lighting system for a more efficient one. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3670407]