**3.6 Analysis of the potential for generation of photovoltaic energy**

The graph in **Figure 14** shows the results of potential photovoltaic energy generation for the 2 systems (on-grid and off-grid), while **Table 7** presents the total values. It is observed that the on-grid system placed on the roof has significantly higher generation than the off-grid system, located in the brises, of 7,933 kWh/year and 4,155 kWh/year, respectively, which totals 12,088 kWh/year.

## **3.7 Building energy labeling**

The building obtained a level A of energy efficiency label (the higher efficiency level, according to Brazilian National standard), as expected due to the inclusion of bioclimatic and energy efficiency strategies since its conception. Individually, the building envelope obtained EqNum = 5, the lighting system obtained EqNum DPI = 5, and the air conditioning system obtained EqNumVent = 5, related to the Coefficient of Performance (COP) of the machines. Considering a partial level A labeling

**Figure 14.** *Monthly estimated PV solar energy generation for LabZERO|UnB [25].*

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


**Table 7.**

*Total values of photovoltaic energy generation potential in on-grid and off-grid systems.*

obtained individually by these systems, plus a bonus for the rational use of water (40% savings), the energy savings from the network (more than 30%), and the general prerequisite of dividing electrical circuits fulfilled, the overall energy efficiency label obtained for the building is A, the most efficient.

#### **3.8 Energy balance analysis**

The graph in **Figure 15** shows the energy balance between consumption and generation. Even when considering the most conservative consumption, with the use of the conditioning system during the entire period of occupation, the simulations and final calculations prove that the building achieves an average annual electrical energy consumption of 34,29 kWh/m2 .year (7,099.18 kWh/year), which corresponds to a primary energy consumption value of 54,88 kWh/m2 .year (11,358.68 kWh/year). This is a significantly lower number if compared to the average consumption of electricity in office buildings in Brasília, which is close to 130 kWh/m2 .year [24]. As for the distributed generation of electricity in the photovoltaic system, installed on the roof and side area, the value of 58,29 kWh/m2 .year is obtained. The results are consistent with international experiences in similar climates, presented before (**Table 2**). With these data, the achievement of the building NZEB goals, or energy balance close to zero or nil, is achieved. There is, therefore, full compliance with the condition of the NZEB building (almost zero energy balance). It is also proposed that the energy generated in excess should be used to supply electric bikes and other buildings at the University of Brasília campus.

**Figure 15.** *Graph of the energy balance between building consumption and generation [25].*

The building's reduced energy consumption is achieved through architectural and technological strategies (passive and active). In addition to aspects of energy efficiency and comfort, the building project proposes strategies for the rational use of water and waste management. Sustainability aspects are also highlighted. An example is the steel structure and the sealing in prefabricated panels, which allow for quick and clean construction, reducing waste generation and the replicability of the typology.

## **4. Conclusions and perspectives**

The integrated design process, used as a methodology, proved to be efficient and highlighted the possibility of transposing research experiences into design practice. The barriers and potentialities related to the coordination of a multidisciplinary team and the organization, planning, and achievement of the goals in the integrated project process stand out. It is important to highlight the role of the computer simulation and the team in charge of this item in the design process, which must interact with others and effectively communicate the results. The project also underlines the importance of the facilitators, who coordinate the feedback loops of the computer simulations and architectural, the technological decisions between specialized teams and the group as a whole, in addition to defining deadlines and levels of detail for each specialty. Communication problems in the team can constitute barriers in the process, and the tendency of excessive detailing by experts at the beginning of the design process must be monitored by the facilitators.

The tools for analyzing environmental and energy performances through computer simulations are key parts to verify the zero-energy balance of a building and the fundamental elements in design decision-making. With these tools, the performance results can be accurately estimated.

In addition to being a building with a zero-energy balance, LabZERO|UnB is a project with the capability to achieve a positive energy balance, by offering an annual generation higher than its consumption. It has a demand of 34,29 kWh/m2 . year and a generation of 54, 88 kWh/m2 . year, which represents the potential to become a construction that has a positive energy balance with a 60% margin. This result occurs even considering conservative hypotheses of consumption reduction – such as constant use of artificial conditioning, with passive potential and office equipment with regular efficiency. Thus, the reduction in the energy consumption pattern from 131 kWh/m<sup>2</sup> . year to 34 kWh/m<sup>2</sup> . year is mainly due to solutions linked to the characteristics of the architectural project, such as shape, envelope, quantity, and opening orientation, combined with high-performance, artificial lighting, and mechanical conditioning systems. These indicate the advantage of considering environmental performance demands from the early stages of the project to achieve high-performance buildings.

It is expected that the construction of LabZERO|UnB, as well as the ELETROBRAS/PROCEL competition initiative, will be a milestone in the development of high-energy performance buildings in Brazil and zero-energy balance constructions. However, there is a need to incorporate environmental and energy performances analysis tools in the scope of the architectural project development from the preliminary stages, keeping in mind the operation and monitoring phases.

As a result, the project achieved an energy consumption of almost four times lower than the local average for office buildings, and this is compatible with international experiences. As the energy generation exceeds the demand, the NZEB building has
