ZEMCH 2019 International Conference Proceedings April.2020 | Page 35
1. Introduction
Currently, there are several processes that can be assumed for architectural design, ranging from
reference schemes to design procedures through parametric computational programs. However, a
point cannot be overlooked by architects, such as the buildingʹs necessary relationship with the local
climate [1].
With the use of mechanical ventilation and air conditioning equipment that modulates weather
conditions inside a building, more and more architects erroneously rely on these machines to ensure
the thermal comfort of their buildings. Thus, there is a reproduction of projects in the mold of what is
abroad: glazed works with a wide view of the landscape. However, not only would an air conditioning
system be sufficient to guarantee this comfort: other issues may affect users, such as direct solar
radiation, lighting, noise, air quality, among other factors. These questions justify the current concerns
regarding this type of building style, being not only about the health and comfort of the people but also
related to the environmental issues and excessive electricity expenses of this type of building.
According to NBR 15220‐3: 2005 [2] (technical standard created by the Brazilian Association of
Technical Standards), the city of Rio de Janeiro is in the Bioclimatic Zone 8 and has, among its
guidelines, the recommendation of large openings for ventilation and shading to prevent glare and
overheating. Some mitigation can still be achieved through adequate means of temperature control
systems and artificial lighting. According to the National Electricity Conservation Program (PROCEL),
about 23% of national electricity production is used in commercial and public buildings. According to
Geller [3], 44% of the electricity used in commercial buildings in São Paulo comes from the use of
artificial lighting and 20% comes from the use of air conditioners, which is why it can be demonstrated
the responsibility of professionals to reduce the final electric consumption.
Therefore, the present research seeks in part to find solutions to these questions and deals with the
problems related to natural lighting due to the characteristics of the building façade orientation,
fenestrations, and indoor conditions. Concerning energy savings, other important points are the
characteristics of the luminaires and lamps and their locations, as an artificial light control system, when
there is a reduction of natural lighting throughout the day in the room.
2. Materials and Methods
This work evaluates the natural lighting conditions in a classroom of the Federal University of Rio
de Janeiro, using NatLite and RadLite [4] software. This analysis is performed under three steps: (i)
Indoor and outdoor luminance calculations to obtain the Daylight Factor values at selected points in
the room, already predetermined by a mesh; (ii) Evaluate indoor glare conditions; and (iii) Proposal
and performance analysis for employing light‐shelves on the building façades to improve indoor
lighting conditions.
2.1. Evaluation of the quality of natural daylight indoors
With the concern of taking advantage of natural light indoors and the need to evaluate the lighting
conditions, a merit figure is the Daylight Factor (DF). This relates the indoor illuminance (Ei) with that
one incident on exterior building façade (Eo), see Equation 1:
DF = (Ei / Eo) . 100 (%)
Were:
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DF < 1% = Insufficient | 1% < DF < 2% = Neutral | 2% < DF < 4% = Good | DF ≥ 4% = Great
The daylight factor is an indicator widely used in the 1970s by many researchers [5] for natural lighting
purposes under conditions of uniform overcast CIE sky, by CIE (CIE (International Commission on
Illumination). A predefined mash of grid points for the classroom is considered, under each column as
the basis for analysis. The computer program applied for such analysis is the RadLite [4], which brings
the possibility to obtain the exterior façade and indoor values of illuminance. This software was used
Evaluation of Energy Efficiency and Natural Lighting: Case Study of the Classroom Environment
of the School of Architecture and Urbanism of the Federal University of Rio De Janeiro - FAU-UFRJ 24