**2. Research and design for an NZEB**

#### **2.1 Integrated design process of an NZEB building**

Note that the characteristic of this type of building involves a project that integrates passive and active systems, in addition to the specification of optimized ventilation and air conditioning systems, connecting natural light and power generation. On the other hand, design practice must shift from a traditional linear process to a collaborative approach between architects, structural engineers, mechanics,

electricians, and other professionals. By definition, the Integrated Design Process (IDP) guides decision-making in various professional specialties, including the use of natural resources, energy consumption, and the achievement of environmental quality [7, 10]. Kwok and Grondzik [16] define the IDP as one that synergistically involves several disciplines, to create more efficient and responsible buildings with a lower life cycle cost. Keeler and Burke [10] conceptualize it as a synonym for sustainable design. The authors emphasize that in the case of integrated design, it is important to understand the design variables as a unified whole, involving decisions about energy consumption, natural resources, and environmental quality.

The main features of the integrated project are:

**Iterative, non-linear process**: In contrast to the conventional (linear) design process, in which team members work in isolation, PPI promotes ever-increasing feedback loops among everyone;

**Collaboration and innovation**: All participants must share the same vision of the project from the beginning, in order to provide input and feedback to the rest of the team. Project contributors may be asked to work on tasks outside their usual objective. PPI encourages everyone to share the learning and improve the process as a whole;

**Multidisciplinary team**: Ideally, the PPI includes all stakeholders in a project, and they must be present from the early stages of the work, providing their expertise to the project process. There may be other consultants, depending on the specific needs of each project [7].

These authors mention strategies and aspects related to the design of the NZEB building, by pointing out the design issue and listing the iterative phases of design in **Conceptual Design**, **Project Development,** and **Technical Design**, as shown in **Figure 1**.

Another aspect mentioned by the same authors is related to technical and research matters, in which they highlight the computational model simulation that is going to be used. The importance of research inputs to be applied during the design process is also emphasized. In order words, the development of an NZEB project requires prior knowledge and research, especially in cases of restricted deadlines. Monteiro et al. [17] state that in this type of project, computer simulation has become a mandatory step in the process, adding complexity, but favoring the improvement of the project.

#### **Figure 1.**

*Iterative phases of the NZEB design process. Source: Adapted from [7].*

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

Mendes and Amorim [18] report an experience of applying the concepts of Integrated Project in a graduate discipline, during which the method proposed by O'Brien et al. [7] was used with two crucial factors: well-defined project objectives shared by the entire team and the presence of a facilitator (coordinator), who sets the tone for collaboration and effective communications during the design process. There was also the creation of teams of specialists in the various themes to be addressed in the project, along with the establishment of periodic meetings with the entire group to share results and align actions. A team specialized in computer simulations acted transversally, receiving and providing inputs to the others. The experience proved to be efficient, noting that the design process reached appropriate fluidity and the project proposed in the discipline achieved appropriate technical results, with an energy consumption lower than its production, reaching the goal of becoming an energy balance building null [18]. This was defined as the basis of the method to be used in the LabZERO|UnB integrated design experience.

NZEB design, monitoring, and benchmarking experiences reported by Garde and Donn [19] present 30 residential and non-residential case studies, grouped into cold, moderate, and hot climates. Three of these buildings can be compared to the conditions of LabZERO|UnB due to the similarities in use and climatic conditions. In these cases, energy demands ranging from 16 to 66 kWh/m2 .year are identified, with energy production ranging from 44 to 115 kWh/m2 .year. In one case, energy production is 7 times greater than the demand. **Table 2** presents energy demand and production data.

#### **2.2 Team definition, initial guidelines, and preliminary design**

The definition of the team is an important part of the project conception, as their profile must be able to provide the full development of the products, within the stipulated time limit. It also established the involvement of administrative bodies linked to the project and construction management of the University, as it is a proposal for the construction of a building on the campus, involving bureaucratic issues and administrative actions. Furthermore, the expertise of technicians linked to the university's construction sector is essential for the development of the project in accordance with internal rules. More than that, the technicians carry out theoretical work, resulting from research in the area, and act at the same time in training regarding the bioclimatic project, energy efficiency, etc. This partnership between research and project/ action is seen as crucial to leverage more effective actions towards greater efficiency in construction on the University campuses as a whole. In conclusion, there is a need for a mixed team that combines a variety of researchers and professionals from different


#### **Table 2.**

*Energy demand and production in 3 NZEBs. Source: [19].*

specialties and modes of activity, able to apply the concepts of previous research and work developed by teams of professors and researchers and implement them in the project proposal in an agile way.

Once defining the team, meetings there will be meetings to take preliminary decisions regarding the nature and size of the project, considering budget and deadline limitations. Other decisions taken preliminarily are related to the type of the building (residential, commercial), function, and location on the University campus. According to the methodology proposed by O'Brien et al. [7], the team facilitator should have the task of delimiting attributions for each of the participants and defining the delivery deadlines, depending on the necessary feedback from each phase of the project. The technical drawings required by the contest announcement were: topographic survey; location and situation plan; architectural project; hydraulic installations design; electrical installations; air conditioning; lighting; and distributed generation project from renewable sources. Besides the Basic Project, there were other mandatory items to be delivered, such as Requirements of Use, Descriptive Memorandum, Budget, Schedule, Energy consumption, and distributed generation evaluation report and Preliminary Visitation Plan. It is noteworthy that the building must be open to visitation and monitored within 24months of its construction, to allow the measurement of its real performance.

The preliminary design of the building was done with a defined area due to budget constraints. Initial decisions and common goals must be developed with the participation of all.

According to the premises established in the methodology, the participants chosen were members of the research groups and laboratories at the University of Brasilia and those working closely with the NZEB theme and disciplines related, such as the postgraduate course Integrated Environmental Project, created in 2017 and taught in the Postgraduate Program in Architecture and Urbanism at the University of Brasília. This core team is coordinated by professors of the Architecture and Urban Planning -(Laboratory of Environmental Control and Energy Efficiency - LACAM), alongside with professors of Mechanical Engineering (Air-Conditioning Laboratory - LaAr) and Electrical (LARA - Automation and Laboratory) Robotics), partners since 2014 in the development of disciplines, undergraduate and graduate final works on the subject [20–22]. Professors of Geology and Environmental Science were also involved to develop themes related to the project's sustainability (water, waste, etc.).

The team was defined with 24 members, as follows: 2 architects specialized in energy efficiency, process coordinators; 2 specialists in a computer simulation, who transit between all other teams; 1 architect specialized in energy efficiency; 3 architects and 1 civil engineer without training in energy efficiency; 1 mechanical engineer specialized in energy efficiency (responsible for HVAC); 2 specialists in electrical engineers (1 responsible for photovoltaic energy generation, the other for controls and automation); 2 engineers specialized in budgeting; 2 engineers specialized in the use of water and waste; and 4 undergraduate students in Architecture. There was also the collaboration of a company residing in the University's Science and Technology Park, a specialist in energy efficiency labeling in buildings, and a junior company active in the field of civil construction, composed of graduate students in Civil Engineering and experts in the preparation of budgets for construction.

It was initially considered to use an NZEB residential building project, the result of an existing master's dissertation [22], but impasses regarding the use and occupation of a residential establishment on a university campus, in particular related to security and monitoring, eliminated this proposal. The second hypothesis dealt with the use of

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

a retrofit project, carried out previously [15], in an existing building on the campus. In this case, the limiting factor was the cost, since it is a large building, the budget would exceed the amount offered by the Public Call. The Birck project [20], previously mentioned, due to its large area would also present a high cost. It was therefore decided to carry out a new building project on the campus.

After the initial discussions, the project's objective was defined as follows: to build an open and collaborative laboratory, which would allow for some flexibility in the plant without specific programmatic needs.

The city of Brasilia, where LabZERO|UnB will be constructed, is located in the central area of Brazil (latitude 15°46'South and longitude 47°55´ West) (**Figure 2**) and it has a climate that is classified as high-altitude tropical climate or Tropical savanna climate (*Aw*, according to the Köppen climate classification), milder due to the elevation (1.100 m). This climate is characterized by a rainy season, from October to April, and a dry season, from May to September. The average temperature is 21.0 C.

Initial design guidelines included local climate recommendations in bioclimatic zone 4 as per ABNT 15220 [23], which indicates shading, controlled natural ventilation, light and insulated roof, limited window-wall ratio, and light colors. Additionally, a floor plan with reduced depth was defined to favor natural lighting and it was installed with the largest façades facing North and South, to reduce the incidence of sunlight and optimize the protection of the façades. The roof houses the photovoltaic panels, as well as the North façade, which receives photovoltaic brises

#### **Figure 2.**

*Koppen-Geiger classification map for South America. Source: Beck, H.E., Zimmermann, N. E., McVicar, T. R., Vergopolan, N., berg, a.; wood, E. F.; present and future Köppen-Geiger climate classification maps at 1-km resolution nature scientific data. DOI:10.1038/sdata.2018.214., CC BY 4.0, https://commons.wikimedia.org/w/ index.php?curid=74674070.*

that also work as solar protection. The first design sketches (**Figure 3**) were developed based on these guidelines, but they gradually evolved as a result of discussions of the various aspects with the entire team. It is worth noting that the design process sought to harmonize esthetics with the local context of the university campus.

#### **2.3 Simulations and preliminary draft**

Computer simulations are carried out after the definition of the preliminary design to validate the first decisions regarding the implementation and orientation, the form of building, glazed area, solar protection systems, solar exposure for solar and photovoltaic panels. Some design variations and sensitive variables that feedback into the design process are tested in an integrated design action, in which team members participate. This process takes several weeks until an ideal energy solution is obtained.

To assess the building's energy performance, the Energyplus software was used through the DesignBuilder graphical interface for a period of a typical year. The results are presented by the energy consumption in kWh/m<sup>2</sup> .year. The same software is used to perform the passive potential performance of the building's coworking area. In this case, the results are checked by the percentage of hours occupied in comfort using the adaptive comfort model of ASHRAE-55 for both 80% acceptability and 90%. As for the evaluation of the luminous performance of the coworking area, the Radiance program is used, through the Rhinoceros 3D program and its visual programming language Grasshopper and the add-on HoneyBee. The Daylight Autonomy (DA) is evaluated at 300 lux, and the Useful Daylight Illuminance (UDI) above 2000 lux.

The Basic Project, which is the level that the NZEB building proposal should be delivered for the PROCEL EDIFICA 2019 call notice [14], was defined after some alternatives were tested by simulation, in particular regarding sun protection, types of glass (light transmission and solar factor) and building materials (roofing and walls). In this phase, automation, and control strategies (HVAC and lighting), location of photovoltaic panels, such as Renewable Energy Technology (RET), lighting design, and other sustainability strategies, such as rational use of water and waste treatment, were also defined by teams of engineers and experts. The team participated in an integrated way. The group responsible for the simulations brought about results, which were evaluated under different aspects (energy, esthetic, functional, cost) before taking the final decision on the project.

**Figure 3.** *Sketches with the first preliminary design risk, later revised (plan, volume, and section). Source: Authors.*

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

Due to the first thermo-energetic simulations and daylighting, the preliminary design of the building was established.

After another round of simulations, the Basic Project was defined, bringing details of the preliminary project, such as envelope materials with thermal transmittance and absorptance suitable for the bioclimatic context (external walls, fiber cement panels, rock wool insulation, and plasterboard, U = 0.89 W/m<sup>2</sup> .K; steel deck slab coverage, metallic tile, and insulation, U = 0.57 W/m<sup>2</sup> .K); artificial lighting system with efficient lamps, luminaires, and task lighting; and automation for HVAC and artificial lighting.

#### **2.4 Simulations and final calculations**

After the definitions of the Basic Project, the feedback from the initial simulations, and the tests of several hypotheses, the final simulations of energy consumption involved the same software mentioned above. In addition to these, the RELUX software was used for simulations of the lighting project, the SAM software of the National Renewable Energy Laboratory (NREL) for dimensioning and calculation of two independent photovoltaic systems: on-grid and off-grid. Finally, energy efficiency labeling calculations, primary energy consumption, and budgets for final solutions, required by the notice, were performed. Regarding the budgets, a junior civil engineering company was counted on, which made the quotations of 21 items, plus the percentage of BDI, according to the model of the Public Call [14].

The simulations and final calculations prove that the building achieves an average annual consumption of electrical energy of 34.29 kWh/m2. year (7099.18 kWh/year), which corresponds to a primary energy consumption value of 54.88 kWh/m2 .year (11,358.68 kWh/year), that is significantly lower compared to the average consumption of electricity in office buildings in Brasília, which is around 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 obtained is 58.29 kWh/m2.year. The results are consistent with international experiences in similar climates, presented above (**Table 2**). With these data, the achievement of the goal of building NZEB, or energy balance close to zero or nil, is proven.

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 proposes strategies for the rational use of water and waste management. Sustainability aspects are also highlighted, such as the steel structure and the sealings in prefabricated panels, allowing for quick and clean construction, with less waste generation and possible replicability of the typology.

The building obtained a level A energy efficiency label (the higher efficiency level, according to Brazilian National standards) as expected due to the inclusion of bioclimatic and energy efficiency strategies since its conception. In isolation, the envelope obtained EqNum = 5, the lighting obtained EqNum DPI = 5, and the air conditioning EqNumVent = 5, related to the Coefficient of Performance (COP) of the machines, with partial level A labels being obtained individually. As a bonus, it was counted the rational use of water (40% savings) and the energy savings from the network (more than 30%). The general prerequisite of dividing electrical circuits was also fulfilled. Therefore, the overall energy efficiency label obtained for the building is level A.
