NZEB schools in italy: definition and optimization of system using photovoltaic technology - american congress rehabend 2020

The realization of a Nearly Zero Energy Building (nZEB) school cannot ignore the proper design of the building distinguishing features (shape, orientation and distribution of functional bands and units, window-to-wall ratio – WWR, structure, technological solution for the external envelope, solar shadings etc.) already during the preliminary phase of the design process in order to minimize the energy needs according to the climate zone of construction. At the same time it is necessary to identify the appropriate relationship between building and plant and consequently the share of energy ensures by renewables. In Italy, since 1st January 2017, for new buildings the 50% of energy needs for service hot water, heating and cooling must be guarantee by renewable energy. This is strictly related to the demands of “2050 low-carbon economy” (2018) that requires a decrease in greenhouse gas emissions equal to 80% by 2050. The paper concerns with the three new typological models for kindergartens, defined in a previous stage of the research, to design Nzeb schools in the Mediterranean area: one with compact shape with internal courtyard and two with a predominant linear shape respectively with three and six classrooms. In this case an electric heat pump (air-water) for heating, ventilation and air conditioning (HVAC) and service hot water powered by an integrated photovoltaic system in the building and lighting systems, plackloads and auxiliary system related to HVAC with high energy efficiency were used. The study aims at investiganting the influence on energy produced by photovoltaic panels of the shape and the geometry of the roof and the orientation of the building, considering three cities belonging to different Italian climate zones. The modeling of the system and the energy simulation in dynamic regime with hourly time step were carried out with Design Builder. To estimate the energy production of photovoltaic panels PVGIS software was used considering the system extendend to the available area of the roof. The goal is to define and to optimize the system in term of electricity production, in order to obtain a positive electricity balance and make the system able to share energy with other users.