A strong consortium of leading European technical universities such as the Technische Universität Darmstadt (Germany), the Delft University of Technology (The Netherlands), the Materials Physics Center (Spain), etc. as well as a number of EU industrial representatives, among which one of the leaders on the Bulgarian construction market – “Glavbolgarstroy” continue their active work on an innovative project, financed by the EU’s largest research program “Horizon 2020” (currently Horizon Europe).

The revolutionary NRG-Storage project seeks to launch a novel breakthrough solution that replaces the currently available insulation materials used in building envelopes, by proposing a multi-functional and eNeRGy saving cementitious Foam (NRG-Foam). The concept targets non-residential buildings and aims to achieve 25% better insulation capacity and at least 10% higher energy storage capacity. The layer of the multi-functional and eNeRGy saving cementitious Foam (NRG-Foam) shall be characterized also with a higher water and air tightness (between 10% and 25% higher than existing solutions) and with at least 15% lower costs than the actual solutions available in Europe. The heat-activated foam will be used for passive/active management of energy transfer and will be applied to new building envelopes. Graphene-based nano-additives and Phase Change Materials will be embedded in order to improve the thermal energy storage capacity, volume stability and mechanical properties of the resulting composites.

To test the developed in the course of the project innovative insulation material, the NRG-Storage project foresees the application of the NRG-Foam on: 27 demonstration walls; 3 or 4 new full-scale demonstration buildings based in Bulgaria; as well as on 2 demo sites of existing non-residential constructions in Spain and Germany.

As part of the intensive work on the project, a German delegation visited Bulgaria in the starting days of October 2021 to follow/inspect the on-going construction of the full-scale demonstration buildings in Sofia. The Bulgarian company Glavbolgarstroy is engaged with the actual realization of the demo buildings in Bulgaria, as well as with their follow-up daily monitoring for a period of two consecutive years.

Among the members of the delegation were Prof. Dr. E.A.B. Koenders – Head of the Institute of Construction and Building Materials (WiB) at the Faculty of Civil and Environmental engineering at the Technical University Darmstadt and Dr. Frank Röser, CEO of RÖSER Ingenieurbeton. The Technical University in Darmstadt is in charge for the actual development, design and optimization of the insulation foam, while the industrial partner from RÖSER Ingenieurbeton is responsible for the application of the façade elements with the NRG-Foam at the demo buildings in Sofia.

In the course of the visit, the project’s teams from the Technical University in Darmstadt, RÖSER Ingenieurbeton and Glavbolgarstroy carried out intensive discussions at the GBS headquarters in Sofia and at the construction site at Krivina (Sofia municipality) regarding the application of the innovative insolation material at the demo buildings and the specificities of its follow-up monitoring and data gathering. During the next project’s stage the buildings’ performance shall be monitored for a period of 2 years with a view to prove the thermal insulation and energy storage capabilities via temperature sensors. The air temperature and temperature of the surfaces in buildings shall be observed on a daily basis, together with the respective weather resistance, thermal bridges and low insulation points, as well as energy efficiency with regards to consumption of energy for heating and cooling.