Análise de viabilidade de um edifício comercial atingir o balanço energético nulo, a partir de diferentes níveis de eficiência energética, no extremo sul do Brasil

Abstract

The Brazilian energy matrix, despite being diversified, has hydraulics as its main source. Although this is a renewable energy source (RES), it has great socioenvironmental impacts, high transmission costs and is fragile since it is centralized and far from urban centers. Considering that the country has a large territorial area with climatic diversification, there is potential for exploring other RES of distributed generation. From these, solar energy through photovoltaic technologies (PV) stands out. Because they are easy to integrate with buildings and considering that these are responsible for a high energy consumption, such a combination is a relevant factor for a sustainable future. In this context, the integration of PV technologies in commercial buildings has been shown to be adequate, as the predominance of occupation and the highest energy consumption occur during the day, simultaneously with the energy production by the PV modules. Hence, the objective of this work is to analyze the economic viability of a horizontal office building, in the extreme south of Brazil, to achieve zero energy balance through different levels of energy efficiency. For this purpose, the adopted methodology used computational simulation, through the EnergyPlus software, and the calculation of PV energy generation, with the help of the Radiasol program. In the analysis of economic feasibility, the Net Present Value (NPV) and Internal Rate of Return (IRR) calculation methods were used, thus evaluating the investment required for each proposed photovoltaic system (PVS) deployment and the avoided costs with economy of generated energy. Results indicated that the object of study is classified A in energy efficiency, according to INI-C, thus enabling the identification of reference cases B, C and D. Cases A, B and C reached the zero energy balance, through PV technologies applied to the roof and the opaque parts of façades, and case D was not able to compensate its annual consumption through the PVS, as there was not enough area for the application of PV modules. Results also revealed that the higher the level of efficiency, the faster the zero energy balance and the return on the initial investment of the PVS implementation were achieved, observing a variation of up to 58.94% over the minimum amount to be invested. It was also verified, through the IRR method, that even in less favorable scenarios for investment with PVS, a value of 20.22% was obtained at the end of the 25-year period (useful life of the PV modules), a value considerably higher when compared to the highest rate of attractiveness defined in this study (13.20%/year), percentage of profitability for lowrisk banking investments. As for the PVS method, the payback period for the case of greater energy efficiency was 5 years and 5 months, while the case of lower efficiency took up to 10 years and 8 months, corresponding to an increase of 96.92% between the extremes. This study demonstrated the importance of the relationship between energy efficiency and self-energy generation to obtain buildings with a zero energy balance.