Design transformation from standard conformity to Net Surplus Energy

Abstract

The energy performance of buildings directive requires all new buildings to be near zero by 2020. With that target year approaching, the lacking definition of what "near zero" actually means becomes increasingly prominent. While a weak definition threatens to undermine credibility of near zero claims, it is both environmentally profound, technically feasible and beneficial with regards to user qualities and indoor comfort aspects to plan and build net surplus energy and carbon neutral houses. One goal of the project was to demonstrate that established building developers can shift their building practice to deliver surplus energy homes - without leaving their range of experience. After analysing the base-line-design, incremental improvements focused on optimising the building envelope, including thermal bridges, air-tightness, fault-free insulation. The remaining energy demand is covered entirely from locally available renewable sources. Key elements are building integrated PV and power storage, geothermal heat pump for heating and warm water, ventilation system with heat recovery and LED lighting. The PV installation is designed to generate more than twice the energy needed by the building and the users, providing that surplus to electric mobility applications. Displacing electricity purchased from the grid and displacing fuel combusted in vehicles is key to life cycle carbon and cost optimisation. Energy efficiency is not in conflict with user comfort, especially not with daylight aspects or with architectural design. The successful merger of a wide range of sustainability aspects was highlighted by this building being category winner of the international activehouse awards 2018.