Energy Compensation Model between a Net Zero Energy Building and a School Building

In the European Union, the concept of Net Zero Energy Building (NZEB) has been known for many years, defined as a building with a remarkably high energy performance whose yearly needs are totally compensated by renewable energy sources. This definition often leads to a surplus of renewable energy which, especially if obtained from solar photovoltaics (PV), can lead to a large production of unused energy or to an overload of the national electricity grid. In this regard, the aim of the paper is to prove how the efficiency of these buildings increases when coupled with other less efficient ones, creating an energy compensation model. The basis of the model is the different intended use of the two buildings which therefore leads to different energy demands throughout the day. The model is applied to a residential NZEB, and an existing school building located in the South of Italy. Three scenarios are hypothesized based on the PV peak power installed, i.e.: PV system covers the yearly energy needs of the NZEB; PV system covers the monthly energy needs of the NZEB; PV system covers the yearly energy needs of the school building. The study is performed by means of a dynamic energy simulation software. It shows that in the last two scenarios it is possible to cover a high percentage of the school energy needs (around 50%), by using the electric energy produced by the PV system installed on the residential NZEB.