Housing module with 3D printed walls: nZEB performance, energy autonomy and exported level

In this paper a building-plant system consisting in a housing module with 3D printed walls and a wooden roof is simulated with the dynamic simulation software TRNSYS 18 in coupling with an electric heat pump mainly driven by the electricity of a photovoltaic plant. Energy flows characterizing the system are dynamically assessed and on an annual basis it is evaluated if the condition of nearly Zero Energy Building (nZEB) is reached. Two further indexes - called Building Level of Energy Autonomy (BLEA) and Building Level of Energy Exported (BLEE) - are also calculated to estimate the energy autonomy and the level of energy exported in the proposed configurations. A parametric analysis considering two peak powers for the photovoltaic system (6.12 kWp and 12.24 kWp) and different sizes for the battery (from 2.16 kWh to 25.92 kWh) are investigated. Results highlights that with both photovoltaic (PV) plant layouts a positive yearly energy balance is obtained. The energy dependence decreases progressively till a certain electric storage capacity (15.12 kWh and 17.28 kWh). Over these values the BLEA stabilizes around 94% and 97% with the smallest and largest dimension of the solar field, respectively. In these conditions 44% and 68% of the produced electricity is fed into the distribution grid.