Technical and Economic Feasibility of Multi-Family Social Housing and Nearly Zero-Energy Buildings in Southern Brazil

Abstract

Several studies have shown that social housing in Brazil usually fails to provide thermal comfort to its occupants. This study aimed to define energy efficiency measures for a representative social housing model to, together with local production of renewable energy, achieve the nearly zero-energy target. The thermal performance and energy efficiency of the representative model were evaluated using computer simulation, considering the southern Brazilian climatic context. An analysis of the economic feasibility of energy efficiency measures was also carried out. The results showed that the nearly zero-energy model with energy efficiency measures on the envelope (EPS and gypsum board in the external walls and rock wall in the roof) and a solar water heating system reduced 13.1% of the annual primary energy consumption in comparison with the representative model. Considering the renewable energy generation in the nearly zero-energy building, the electricity consumption was 38,777.6 kWh/year lower than that in the representative model (57.0% reduction). The economic analysis of the energy efficiency measures indicated a positive net present value and a payback of nearly six years. It was concluded that using energy efficiency measures and an on-site renewable made it possible to reach the nearly zero-energy target in a representative social housing model.