The envelope (façade) of a building is the first barrier between the exterior and the interior of the building and withstands the highest variation of temperature and solar radiation. Trombe walls are used to take advantage of that and contribute to the heating of interior air, helping the heating system. In this study, a new Trombe wall design is presented with the aim to contribute significantly to the ventilation of residential buildings. For this an exterior wall equipped with a proposed Trombe system was studied in a numerical simulation analysis. The proposed systems consist of two parts, the air cavities on the exterior of the wall, covered with silica glass, and another layer used for heat transfer, on the interior, comprised of a MPCLBs wall of 115mm. Two cities in Romania were considered to represent the coldest and hottest climate in Romania. Brașov representing the cold climate and Constanța representing the hot climate. In the investigation, both the presence and absence of solar radiation were taken into account. In total 4 cases were established. For all four cases monthly research was made using monthly means temperature, direct and diffuse solar radiation. The results are promising and illustrate that the system works the best during the transitional seasons of spring and autumn. The lower the outdoor temperature the higher the temperature can be increased. Overall, solar radiation accounted for an average of 2 °C increase. The temperature increase varied between 3.4 °C to 15.99 °C for Brașov and between 6.42 °C to 12.07 °C in Constanța.

Earth’s climate cannot be ignored any longer. Policies are vital in order to mitigate the negative effects of climate change. The energy crisis created by the Russo-Ukrainian war and pandemic affected the EU and its member states. The focus is more than ever on its energy policies and independence. The EU revised the energy strategy in response to Russia’s blackmail, and it sped up all the processes for energetic independence from Russia. This benefited the climate change policies the most, as all the measures involved reducing energy consumption and increasing renewables, thus contributing to reducing greenhouse gas emissions. As a member state of the EU, Romania is committed to complying with EU regulations. With a high degree of energy independence compared with the other EU members, Romania plans to become a regional energy provider and modernize the energy infrastructure internally as a response to Russia’s unprovoked aggression. The measures that the EU and Romania implemented after the war started in 2022 have come to fruition, and the effects are becoming visible a year later. This study aims to study the energy strategy of Romania in correlation with the EU strategy in the turbulent period of pandemics and war between 2019 and 2023, with the latest available data.