A study on design optimization of a near net-zero energy house

Net Zero Energy Building design is a very important issue, since to reach the 2020 goal, an effective combination of envelope energy efficiency and integrated renewable systems is required. This paper investigates the case of a house located in northern Italy, in a temperate climate with warm summer. Starting from the actual energyefficient design of the house, parametric analyses are developed with the aim of understanding the effects of alternative / additional strategies that may lead to the "nearly zero energy" performance. The variables considered in the parametrical analysis are related to the building envelope. On the energy demand side, passive solar design techniques such as passive solar heating, insulation and air tightness, solar control windows, shading and interior layout were taken into account to reduce the energy demand of the building. Innovative materials in the design and construction of the vertical and horizontal envelope were considered as well. Energy modeling was performed with the TRNSYS software in order to assess the energy transient behaviour of the house.