Suitability of Test Reference Year for performance assessment of buildings with PV-battery system

This study investigated the representativeness of Test Reference Year (TRY) for the estimation of the performance of a system with photovoltaic (PV) modules and a battery energy storage system (BESS) in a high performance building. According to the technical standard EN ISO 15927-4:2005, the TRY is an artificial year made of 12 actual months selected according to the Finkelstein-Schafer statistics. Even if it commonly used as boundary condition in building performance simulation, the procedure adopted for its definition does not explicitly consider the representativeness of short-term dynamics, such as daily and hourly sequential patterns of weather variables. This can introduce limitations to assess specific systems in modern buildings, such PV and BESS, since hourly and daily sequences can affect charge and discharge cycles of the battery.
In order to study this problem, a three-floor semi-detached terraced house equipped with a PV-BESS was used as case study, considering both multi-year and TRY weather data for three locations, i.e., De Bilt in the Netherlands, Trento and Padova in Italy. After comparing monthly heating degree-days and solar irradiance values of multi-year and TRY weather files, their impact on the simulated performance of the PV-BESS was examined at both monthly and annual scale. Results show that, in the studied locations, TRY weather files proved to be sufficiently representative for a long-term annual estimation of the PV-battery sytem performance. However, significant differences can be observed at monthly scale.