**3.4 Analysis of the lighting system**

The adoption of high-efficiency solutions enabled an average illuminance of 411 lux in the coworking environment, as indicated by the simulations in Relux. At the workstations, the use of task luminaires that increase the illuminance to 500 lux on average is foreseen, as required by the NBR ISO/CIE 8995-1:2013 standard [31].

Thus, the project predicts a total of 54 luminaires, considering all areas and environments, with a total power of 801 W and a lighting power density (LPD) of 3.87 W/m2 . The minimum illuminance level required by NBR ISO/CIE 8995-1:2013 [31], entails an increase of 1 W/m<sup>2</sup> , which raises the DPI to 4.87 W/m<sup>2</sup> . Even so, this

#### **Figure 12.**

*Useful daylight Illuminance (UDI) map above 2000 lux for the Coworking and balcony area [25].*

*An Integrated Design Process in Practice: A Nearly Zero Energy Building at the University… DOI: http://dx.doi.org/10.5772/intechopen.102443*

performance is considerably higher than the limit estimated by label A, according to the PBE Edifica PROCEL classification [11]. This demonstrates, in part, the potential for reducing LPD by using high-efficiency equipment.

This low LPD, combined with the control and automation system with sensors and dimming of the integration system between day and artificial lighting, allows a significant reduction in energy consumption. These elements are considered and verified later in the evaluation through simulation of energy performance.

#### **3.5 Energy performance analysis**

The building's energy consumption results assume a conservative scenario, with artificial conditioning of the coworking area throughout its occupation. However, the main objective of the project proposal foresees that conditioning should be applied only in situations when thermal comfort is not provided. Especially due to the great potential of using passive strategies. Nevertheless, it is prudent to take a conservative stance to ensure that the project will reach its goal of a building with a zero-energy balance.

Given the potential of taking advantage of natural light, the low demand for artificial lighting, the high-performance envelope, and efficient air conditioning equipment, it is possible to obtain an energy consumption of 34.30 kWh/m<sup>2</sup> .year, as shown in **Table 6**. As a comparison criterion, the value obtained is considerably lower than the standards for corporate environments in Brasília-DF listed by [27], which demonstrates an average consumption of 131 kWh/m2 .year.

Thus, the division of consumption by final use, as shown in **Figure 13**, is considerably different from the typical consumption for commercial buildings foreseen by [32]. Unlike almost half (47%) of the energy consumption being related to the conditioning system, at LabZERO|UnB the conditioning system corresponds to 39%. It is worth noting that this reduction could be even more significant if a less conservative scenario were used regarding the air conditioning adoption. However, a greater reduction, from 22–12%, is seen in the artificial lighting system.

As for other electrical loads (equipment), demand exceeds the 31% predicted by [32], reaching 49% at LabZERO|UnB. This percentage does not reflect a quantitative increase in this type of load. However, it shows that its participation in the energy matrix of the building is greater. In part, this is justified by the fact that air conditioning and lighting systems are the main focus of these studies, being directly linked to architecture. For the calculation of energy demand of other electrical equipment, the standard was kept as a default. According to the very concept of building efficiency, the equipment adopted will probably follow the high-efficiency standards, which


#### **Table 6.**

*Consumption data by final and total uses per year and per year per square meter for the entire building [25].*

**Figure 13.**

*Energy consumption by end-use [25].*

reduces its demand. However, as the proposal aims to seek a more conservative scenario, this reduction was not considered for these environmental and energy performance analyses in the design stage.
