Future buildings will require significant performance improvements to adhere to greenhouse gas mitigation strategies. One method is to consider building components as multifunctional elements. These elements can perform several functions simultaneously, such as energy and structural aspects. As opposed to traditional sequential design in which each building element performs its own dedicated function. The former requires an integrated approach to prioritise the use of renewable energy sources and the reduction of materials. In this paper, we present three multifunctional elements: a lightweight shell roof, a funicular floor and an adaptive solar facade. We focus on the numerical simulation used to integrate thermally active building systems (TABS) and building integrated photovoltaics (BIPV) with lightweight structures. We outline a framework for the integration of the multifunctional element analysis with a dynamic building model and the performance factors of a district energy network. We exemplify the framework through the design of a real experimental building in Zurich, Switzerland. This delivered a net plus energy building (NPEB) with an annual weighted energy demand of 37.8 kW h/m² a and a weighted energy surplus of 45%. The results demonstrate the enhanced performance in terms of operational and embodied emissions.