**6. Energy consumption in a solar house**

The electrical energy consumed in buildings is associated with the use of appliances and equipment, and these are generally the focus when it comes to reducing energy consumption. However, the consumption of these equipment depends not only on its efficiency, but also on the interaction with the envelope of the buildings and with the occupants [45]. Among the equipment used in a residence, those that have their demand and, therefore, their consumption more associated with the physical characteristics of the building are those used for the environmental conditioning, that is, artificial lighting systems and air conditioning.

To better understand residential energy consumption, let us take as an example the Brazilian case. Procel [46], on research into equipment checkout and use habits, rates the specific energy consumption of appliances and equipment in the Brazilian residential sector, as shown in **Figure 6**.

Bioclimatic strategies and the use of natural lighting can contribute to building performance, providing environmental comfort to the occupants and reducing the consumption of electricity with artificial lighting and air conditioning systems.

Decoupling of generation and consumption steps in the energy use cycle contributes to energy inefficiency. The ZEBs can reestablish this connection as they promote greater awareness of the occupants of energy generation and consumption. In this sense, residential automation systems are an important tool to integrate and monitor the different systems operating in a solar house, and inform the occupants about the generation and consumption of energy. The storage of the data of operation and performance of a house allows mapping tendencies that can be analyzed to look for solutions to increase the efficiency in the energy consumption for the maintenance of the environmental comfort [47].

Residential automation has been gaining market space as a way to increase not only the efficiency of the operation of the buildings, but also the comfort, convenience and safety of the occupants. The automation system integrates several components structured into a control skeleton that provides refined measurement data from sensors that detect equipment consumption, home appliances, electronics, lighting systems, power generation systems, temperature conditions, humidity, brightness, meteorological data, presence of people, among others. These, in turn, are registered and can be managed, or controlled, by users through interactive interfaces such as computers, mobile phones and the like.

Studies have shown the possibilities of avoiding waste of energy in energy consumption, or other natural resources such as water, through residential automation systems, which can be programmed to turn on or off equipment based on the presence of people, in the definition of temperature and lighting levels, helping to avoid wasted energy [47, 48].

Bartram and Woodbury [48] point out that the challenge of the automation project is to balance the responsibility of requesting actions on the part of the user and also

#### **Figure 6.** *Share of appliances consumption in Brazilian dwellings [46].*

*Developing a Sustainable Solar-Residence Architecture Like a Home Unit without Energy… DOI: http://dx.doi.org/10.5772/intechopen.102778*

to assist in the accomplishment of these actions. The possibility of viewing historical expenditure data in monthly or annual periods tends to exert a great influence and impact on the user, which can also positively influence the seek for greater conservation of energy [44]. These systems and their interfaces present great potential to extend the design possibilities in homes that aim at energy efficiency and can instigate people to use natural resources more rationally.

#### **6.1 Solar house model**

The use of solar energy, directly or indirectly, in urban or rural buildings has great energy potential [38] and makes it possible to contemplate the energy demands to be used in a solar house. Examples of these uses are: allowing internal heating, which results from the generation of direct solar gains and also by the solar water heating system; effective use of natural lighting and use of shading elements to prevent internal overheating.

A solar house prototype is used as an example to show the application of different sun-use strategies in architecture and is the result of a study carried out in Madrid, Spain, located in the Northern Hemisphere, with geographic position 40.4168° N and 3.7038° W, where the implanted solar geometry was considered. The study allowed us to observe that the south orientation was considered the most favorable, as it benefits from the sun throughout the year. As a result, the geometry is more elongated on the east–west axis, while the largest area of openings is located on the south side of the prototype. However, the roof, which is the surface that receives the highest incidence of solar radiation throughout the year, was chosen for the installation of solar systems. The diagram in **Figure 7** illustrates these strategies [24].

The control of the incidence of solar radiation throughout the year is performed by shading devices, aiding in thermal comfort and the availability of natural light. In the southern facade, a system of automated external blinds was installed. The east and west facades are protected by verandas with bamboo frames. In the interior are applied translucent blinds. Components of high levels of thermal insulation are applied to the floor, walls and roof and the openings are sealed and double-glazed with a low-e coating. The application of these passive solutions for the maintenance of internal thermal comfort gave a daylight autonomy of 60%, contributing to the energy saving. The artificial lighting is designed


**Figure 7.** *Solar house prototype [24, 49].*

#### **Figure 8.**

*Solar house annual energy balance considering the prototype located in Madrid [24, 49].*

to complement the use of natural light and uses LED technology, which ensures greater efficiency than other technologies.

The application of a DHW solar system with evacuated pipe technology, with a solar fraction of about 90%, provides hot water, which can be used to feed radiators for space heating. The PV system consists of 48 modules with an efficiency level of 18.5%, accounting for an installed capacity of 11.04 kWp.

The efficiency of the operation is improved through the use of a home automation system integrated with the equipment and the general prototype process. The system provides to the occupant's information about power generation and consumption, allowing more efficient control of the use of appliances such as for lighting and thermal comfort. This equipment can be programmed to be activated or to work only under certain conditions pre-established by the occupants. The combination of solar systems and strategies for sun use guarantees the prototype a positive energy balance throughout the year, as shown in the graph of **Figure 8**.

The estimation of the annual energy balance of the House prototype was carried out considering its implementation in Madrid. According to the rules and regulations of the SDE, an occupancy schedule was defined and energy consumption of household appliances was estimated considering a couple's daily routine and interior comfort conditions for certain temperature and lighting ranges. Energy consumption and generation calculations, conducted using Energy Plus software by Team Brazil members, also took into account the climate data from Madrid. For the calculation of energy generation, was adopted the same PV panel used in the prototype, which is a monocrystalline technology SunPower 230 Solar Panel with a 15.8% efficiency, and the solar collectors were vacuum system SOLTER PU 200/5 [21].

The prototype Solar House adopts as premise the harnessing of sun. It exemplifies a model of the solar house, designed in the light of an adequate study of solar geometry and solar orientation. In addition, it shows that the combined use of strategies and systems can improve the performance and efficiency of the housing unit.

## **7. Systematization of premises and strategies for a solar house**

Distinct is the premises and strategies for using the sun in the architecture of a solar house, be they design solutions or systems that may be incorporated into the building. As described throughout this study, and demonstrated through the Solar

#### *Developing a Sustainable Solar-Residence Architecture Like a Home Unit without Energy… DOI: http://dx.doi.org/10.5772/intechopen.102778*

House prototype, these strategies relate to one another, interfering with each other, as well as with the outcome of the edification as a whole. Therefore, the earlier the architectural use of the sun is taken into account in the design process, as a guideline in the choices of premises and the strategies to adopt, the greater the benefits arising from the use of this resource in the architecture.

In addition, many factors may limit the application of these assumptions and strategies, e.g., economic, cultural, technical, technological, or other. It is important to see in a systemic way the possible strategies to be adopted and the interfaces between them, to obtain greater energy efficiency and environmental quality as a result, within the limitations of each project. The diagram shown in **Figure 9** starts from the use of solar energy as a fundamental premise in the design of a Solar House. Then the energy demands of a solar house are incorporated and, sequentially, the strategies that can be applied to the use of the sun in the architecture are added to the diagram, increasing the use of technologies and the consequent complexity of the project.

In this work, the premises and strategies considered the most relevant within the scope of this research were listed. There is a multitude of other strategies, or even derivations of the demands and strategies presented. In this way, it would be possible to incorporate to this diagram structure new elements, increasing its complexity and refinement regarding the adoption of design solutions for a solar house.

Thus, starting from the use of the sun as a premise, a housing unit can be considered the most elementary version of a solar house when conceived considering an adequate study of geometry and solar orientation. Other strategies and systems can be incorporated, through different arrangements and combinations of these solutions, improving the performance and efficiency of this unit. In addition, preparing the building so that strategies can be incorporated into future steps, for example, leaving waits for SHS and PVS when they cannot be adopted at first, is also essential considering the lifespan of a solar house.

**Figure 9.** *Demands, premises and design strategies for a solar house.*

**Table 1** presents the summaries of the assumptions and strategies of solar geometry, thermal and visual comfort, solar systems and home automation.

## **8. Outcomes analyses and final considerations**

The use of the premises and strategies of the solar house project allowed satisfactory results in the use of architectural techniques and technologies to keep the climate control and the visual lighting system comfortable [23], as well as resulted in the generation of electricity, with gains physical and economic resources applied to the project.

The Solar House project was dimensioned with balconies and designs to control heat exchanges, for thermal comfort and with large openings to amplify the use of natural light, to aid visual comfort. The automation system, with controllers designed to reduce energy consumption as a function of demand [50, 51] allows the interaction between the resources of the solar system, such as thermal heating, lighting and energy generation by photovoltaic cells [52] and equipment for general use, controlling electricity consumption.

In addition to individual and/or collective projects in the implementation of solar systems, with highly satisfactory results, some countries, such as Denmark, China, Germany and Austria, have made extensive investments in the energy market, with technological solutions in large-scale solar thermal systems [53]. Several contributions from solar resources have motivated the implementation of these models of thermal and electrical energy generation, as they are non-polluting and provide a clean form of energy. In **Figure 10**, the diagram systematically presents the results found.

In Section 6, **Figure 8**, the excess energy available for the electricity grid is presented, at the approximate average value of 1030 kWh/month, equivalent to 58.79% of the total and **Table 3** [21] reinforces the positive results in implantation of solar systems, including the simulated average values of energy generation and consumption in one year.

**Figure 10.** *Diagram of solar energy for a solar house.*


*Developing a Sustainable Solar-Residence Architecture Like a Home Unit without Energy… DOI: http://dx.doi.org/10.5772/intechopen.102778*

#### **Table 3.**

*Generated energy capacity (KWh).*

The data allow showing the Pearson correlation, with r = 0.995, demonstrating a strong positive relationship between generated energy and surplus energy (energy produced minus consumed), which returns to the electricity grid. The percentage of energy exceeded, 58.79%, demonstrates the efficiency level of the solar house's energy system.

The experience in the solar house allowed us to verify some advantages and disadvantages in its implementation in relation to the materials, techniques and equipment of the solar system:


The parameters and variables allow achieving thermal, visual, acoustic, air quality, etc. comfort, depending on the architecture, solar geometry, air temperature, radiant temperature, relative humidity, air velocity, physical activity, clothing, thermal exchanges: conduction, convection, irradiation (thermal gain), etc. They are important to the process of analyzing the premises and strategies of a solar house.

The solar intensity, as well as the temperatures and relative humidity of the air, are important variables for the design of the solar house and, in this sense, the averages, maximum and minimum values of the cities of Madrid and Sao Paulo are presented.

Average temperatures (°C) and relative humidity (%):

Madrid—Average temperature range: from 0–33°C (Min −9°C and Max. 40°C), with average annual temperature: 14°C. Relative air humidity: 10 to 80%, with average annual humidity: 55.4% [54].

Sao Paulo—Average temperature range: from 12–28°C (Min 2°C and Max. 40.4°C), with average annual temperature: 26.1°C. Relative air humidity: 12 to 88%, with average annual humidity: 79.56% [55].

**Table 4** supports the proposal of the efficiency of the solar house, given the growth of the solar energy matrix in Brazil. The Brazilian installed power grew approximately 130% from 2018 to 2019, 70% from 2019 to 2020 and in the first four months of 2021, it had more than 15% [56]. These data provide the potential of the Brazilian electrical matrix about the generation of solar energy, which has a large installation capacity in the country, due to the climate, the reduction of implementation costs and, mainly, for the sustainability and improvement of climate comfort, visual and environmental.


#### **Table 4.**

*Solar energy capacity in Brazil [56].*


#### **Table 5.**

*Correlation of statistical data on Brazilian solar and energy capacity.*

*Developing a Sustainable Solar-Residence Architecture Like a Home Unit without Energy… DOI: http://dx.doi.org/10.5772/intechopen.102778*

The installed solar power in Brazil, in 2018, was 1.8 GW and corresponded to 1.1%, in 2019 it increased to 2.47 GW and, in 2020, to 3.29 GW, representing 1.88% of the matrix Brazilian energy, therefore, shows a significant growth of solar energy in the country.

**Table 5** presents the statistical data, demonstrating a strong relationship between the growth of the capacity of the solar system and the Brazilian energy system, as well as the significance and importance of this modal for the Brazilian energy system.

Strategies and premises are important for the solar house process and statistical data prove this, with r = 0.963 and P-value <5% (0.00000161).

## **9. Conclusions**

In this work, several solutions were presented through which the architecture can benefit from the sun to provide environmental comfort to the occupants and efficiency in the consumption of electricity. The single-family housing typology, due to its characteristics, presents an ease to incorporate many of the premises and strategies presented, from those involving only the study of solar geometry and orientation in relation to the sun, to the incorporation of sophisticated systems and technologies.

The theoretical approach and the practical examples of bioclimatic concepts, material properties, design strategies, solar systems, equipment and technologies for energy conservation, allow us to intuitively understand that all these solutions, if well used, contribute to an architecture of quality, for the benefit of the occupants and the environment. The prototype Solar House was used to demonstrate the practical application of these premises and strategies, as well as the interfaces between them.

The results demonstrate the importance of the solar system for the Brazilian energy matrix and how solar houses contribute to this process of energy reduction, through the sustainable solutions presented in this study.

Finally, it is pointed out the contribution of this type of housing unit towards sustainable development, leading to a reduction in greenhouse gas emissions [24, 49].

## **Acknowledgements**

To Daniela Miwa Uemura (Msc) for the translation from Portuguese to English of this work in the first version, with the content and form, and to Prof. André Luiz Lorenção for general review.
