Achieving the Net Zero Energy target in Northern Italy: lessons learned from an existing Passivhaus with Earth-to-Air Heat Exchanger

The recast of the European Directive on Energy Performance of Buildings introduces the concept of nearly Zero Energy Buildings (ZEB). To obtain a practical interpretation of this building concept, it is necessary to clarify two main issues: (i) how it is possible to select a reliable and agreed upon concept of a nearly ZEB; (ii) which technological features might be used to reach that target. In order to test a design of a ZEB in the South of Europe, we present as case study an Italian Passivhaus located in the Po Valley that has been monitored for 18 months and analyzed through dynamic simulations of calibrated models. In this paper we report, in particular, a selection of the result of the monitoring and simulation phases regarding the contribution (in terms of reduction of the indoor operative temperatures) of Earth-to-Air Heat Exchangers and natural ventilation strategies to meet different summer thermal comfort targets and consequently to avoid the installation of an active cooling system or minimize its use and energy demand.