Cost Optimization of a Nearly Net Zero Energy Building A case Study

Abstract — The Net Zero Energy Building concept has received increasing attention in recent years, until becoming part of the EU policy on energy efficiency in buildings. Recently, a very important focus on cost-effectiveness has also been introduced. In particular, an EU regulation of 16 January 2012 establishes a comparative methodology framework for calculating cost-optimal levels of minimum energy performance requirements for buildings and building elements. The big challenge is to understand how much designers should rely on energy efficiency measures and when instead they should start to apply renewable energy technologies. The study presented in the paper is focused on the synergy between energy–efficiency in terms of envelope and renewable energy utilization to achieve a balanced energy budget over an annual cycle, minimizing at the same time the investment costs. An analysis adopting the cost optimality methodology on a residential case study has been carried out. Coupling TRNSYS 16, a transient system simulation tool, and GenOpt®, an optimization program, an optimization analysis has been performed in order to find a cost-optimal energy performance and to detect the best balance in terms of investment costs in envelope and in energy generation. Keywords- Zero energy building; Net zero energy buildings; Cost optimality analysis. I