Assessment of technical-financial analysis of a zero energy building for Brazilian hot and temperate tropical climate

Abstract

The growing concern about the consumption of electric energy and environmental resources has led to research on sustainable approaches in construction. Efficient buildings have been built not only to attract new investments but also to take environmental considerations into account. Energy-efficient buildings, known as Zero Energy Buildings (ZEB), use a variety of passive strategies for energy efficiency, as well as for reduction in demand for air conditioning, heating and lighting. However, in order to design a ZEB it is necessary to search for energy efficiency strategies related to the climate where the building is located. These techniques impact directly on cost benefit and energy performance. The objective of this research is to identify efficient approaches for housing, taking into account the influence of climate, of solar irradiation for energy generation, for two Brazilian capitals, Salvador and Curitiba. The cities have the climates classified as Af (tropical climate) and Cfb (hot and temperate), respectively. The methodological procedures were divided into three stages: quantification of the consumption of each passive strategy adopted in order to determine the energy saving; analysis of electricity, quantifying the balance between electric demand and generation; and assessment of the life cycle cost of the net present value considering minimum attractive rate of return and payback. The Internal Rate of Return (IRR) was also calculated. The results show that for the city of Salvador the payback is 6.75 years and IRR of 15.06% and for Curitiba payback is 10.25 years and IRR of 8.49%. These outcomes demonstrate that in hot climate payback happens in less time, due to the high incidence of solar radiation in the year. The application of ZEB becomes advantageous due to the fact of climatic diversity, high solar radiation and mild winter and results in higher returns in less time.