*3.2.2 Lighting*

Artificial lighting was designed considering daylighting availability. The computer simulations used to verify the condition of artificial lighting in the building were

#### **Figure 9.**

*On the left, the perspective shows the BIPV solar louvers on the north façade and a solar chimney on the west façade; on the right, the perspective of the south façade source: [25].*

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

**Figure 10.** *On the left, modeling in DesignBuilder and on the right modeling in rhinoceros 3D [25].*

carried out by modeling and calculating the data through the/Relux software, version 2019.3. The objective was to optimize the energy efficiency of the system, ensure adequate lighting rates, according to [27], and serve as a basis for an energy assessment. The input data were: the building geometry (height, width, depth, and useful ceiling height); the artificial lighting equipment in each environment; and the height of the work plane (70 cm).

#### *3.2.3 Thermo-energetic performance*

To analyze the building energy performance and to verify the electricity demand, EnergyPlus 8.9 was used, through the graphic interface DesignBuilder 6.0 (**Figure 10**). The model's geometry followed the architectural design, and the climate file was a Swera type for the city of Brasília-DF.

The loads and schedules utilized are based on the ASHRAE Handbook of Fundamentals [28] mostly for generic office area, which is the predominant occupation. The office breakroom in the outside area and bathrooms follow also the same indications [25], however, they are adapted to the Brazilian reality, so no plug load is considered in these areas. Additionally, since the technical area does not have heavy machinery, instead of the 52 W/m2 considered to this kind of area in the ASHRAE Handbook of Fundamentals (2017), it is employed the same value of generic office area, of 11 W/m<sup>2</sup> , which allows a general load closer to the generic offices found in Brasilia by Costa et al. (2018). The attic is considered unoccupied with no internal loads. Furthermore, the artificial lighting energy values are obtained from the lighting design, with an overall 5 W/m<sup>2</sup> for all environments, meanwhile, in the office area, there is an additional 1 W/m2 for task lighting. **Table 3** summarize these data:

Additionally, the building operation varies from 8 h to 22 h on weekdays and all schedules are derived from this operation period. The simulation is carried out for the whole year and the data analyzed is Energy Use Intensity (EUI) in kWh.year/m2 , considering only the occupied area (not including the attic).

The reflectance of materials is based on the general guidelines of [12], which defines absorbance values for light colors as 0.4 and for dark colors as 0.7. The floor and the ceiling were modeled as dark, while other surfaces were defined as light.

The building envelope thermal properties follow the standards of [23], with [29] reference for modeling in EnergyPlus. The external vertical sealing composition comes from [22], external walls of fiber cement and rock wool (0.89 W/m2 K), in addition to a covering composed of metallic tile with insulation (0.80 W/m2 K), ventilated cavity


#### **Table 3.**

*Occupation, equipment, and lighting power per area type.*

(10 ren/h), and steel deck slab (3.16 W/m2 K). The thermal properties of all layers of the opaque envelope are presented in **Table 4**.

The glass employed on the windows is a clear laminate 13 mm glass (6 mm+1 mm PVB+6 mm) (**Table 5**). All windows have external shading elements, as recommended for this climate.

As for electrical equipment, the installed power follows the RTQ-C as a reference [11], except for lighting that respects the project presented in the analysis of the artificial lighting system. The usage routine is from 8 am to 10 pm 5 days a week. With the exception of the coworking area, the other areas have natural ventilation. Bathrooms, technical area, and balcony have the ventilation network model (airflow network). According to the project, the frames opening rate is 88%.

For the attic zone, a constant rate of 10 renewals per hour is used. The office working area will be equipped with a highly efficient direct expansion HVAC system for cooling purposes. No heating will be employed since it is most frequently necessary late at night when there is no occupation in the building. It is employed ideal air loads for the mechanical systems with a Coefficient of Performance (CoP) of 5, which is a theoretical constant value for the equipment employed. There is also a cooling


#### **Table 4.**

*Opaque envelope thermal characterization.*

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


#### **Table 5.**

*Glass thermal properties.*

setpoint of 24 °C operative temperature with no setbacks. Finally, a water condensing unit is used in combination with an evaporator fan, which blows cold air from a plenum under the floor of the working area.

In addition, there is artificial lighting control in this zone, with setpoints of 150 lux for the balcony area and 300 lux for the coworking area.

#### *3.2.4 Potential for photovoltaic energy generation from on-grid and off-grid systems*

To analyze the potential of photovoltaic energy generation, the SAM software from the National Renewable Energy Laboratory (NREL) was used. Two different photovoltaic systems were designed. The first one was a photovoltaic field of a kind that is connected to the public distribution network (on-grid), integrated to the coverage of the technical area of the building, facing North, with an inclination of 15<sup>o</sup> . The other photovoltaic system was conceived as an integrated field to the design of the brise-soleil that shade the North façade – using a battery bank for storage (offgrid), and will not be directly connected to the public grid. This unusual design is intended to address future research regarding demand energy management.

A system with 12 TRINASOLAR TSM-DE15MII-400 W TALLMAX modules of 400 Wp of monocrystalline silicon was considered for the on-grid system and YINGLI YL100P-17B 2/3 panels 36,100 W POLYCRYSTALLINE CELLS with measures 2.5x66x101cm and 100 W of power in the standard STC test conditions for the off-grid system. For the calculation, the methodology of Pinho and Galdino [30] was used.

#### **3.3 Daylighting analysis**

The daylighting simulation reveals the availability of this resource in the coworking area, as shown in the Daylight Autonomy map (**Figure 11**). There is a predominance of natural light autonomy in the environment for over 80% of the hours during the year, with more than 300 lux. Illuminance values above 2000 lux, which can lead to glare and excessive thermal loads, are punctual and appear less than 40% of the time. In addition, they are concentrated exclusively along the building openings, as shown in **Figure 11**.

In general, and in terms of the high daylight availability when the environments are occupied, the results are satisfactory. Values with an autonomy of 300 lux less than 80% of the time are punctual (behind the wall and in rooms such as pantry and hallway, which usually do not have high lighting demand). Likewise, the compensation to reach higher levels, such as 500 lux in the work planes, can be contemplated by the work luminaires foreseen in the lighting project (task lighting). Furthermore, it is noteworthy that it would be highly restrictive to demand that the entire environment be served by 500 lux. In terms of potential glare, the 2000 lux Useful Daylight Illuminance analysis indicates dew occurrences near the windows, which can eventually be avoided

#### **Figure 11.**

*300 lux daylight autonomy (DA) map for the Coworking and balcony area [25].*

by adopting simple solar protection systems, such as blinds. In the external area and balcony, there are naturally higher rates, especially at the end of the building, which would probably benefit from some kind of greater protection (**Figure 12**).
