Improving the energy efficiency of buildings is a major priority within the context of the European objectives to reduce greenhouse gas emissions by 55% by 2030 and to achieve climate neutrality by 2050. Nearly Zero-Energy Buildings (nZEBs) offer a promising solution to significantly reduce energy consumption and promote the use of renewable energy sources. There is a significant gap in the scholarly literature regarding systematic reviews focused on the advancements in European legislation related to energy efficiency. Consequently, this paper aims to provide a comprehensive synthesis of the key legislative norms targeting the energy efficiency of buildings and the necessity of utilizing renewable energy sources for electricity generation, with a particular focus on the forecasts for the year 2030. The objective is to offer valuable reference resources and to support the global expansion of nZEB implementation in a sustainable and resilient manner. This research thoroughly evaluates the development of nZEBs, emphasizing design concepts, technological innovations, and their impact on energy efficiency. An analysis of the main barriers to implementation highlights high costs, limited technological feasibility, regulatory constraints, and insufficient stakeholder engagement. The purpose of this paper is to review the literature on building energy efficiency and the European trajectory from passive to zero-energy buildings.

Off-grid hybrid renewable energy systems represent the most modern and flexible solutions that can cover a wide range of energy efficiency needs for household consumers. In the current context, these systems must be taken into account by most household consumers, given the fact that the price of energy has increased. This paper proposes an experimental analysis of the behavior of such a system, in real operating conditions, considering two renewable energy sources, wind and photovoltaic sources, using an experimental stand. It can be considered a testing platform for hybrid energy production systems, in that the power installed in the two sources can be scaled up. The platform has the advantage of allowing the implementation of different load and wind curves through a programmable logic controller; in this way, it is possible to evaluate the degree of coverage of the energy consumption produced from renewable sources, in the north-east of Romania, in the Suceava County region. The experimental study also involves an analysis of the storage capacity in relation to the consumption and the electricity produced by the two renewable sources. In this regard, three scenarios differentiated by the state of charge (30%, 50% and 70%) have been established. The results indicate that, for each of the imposed scenarios, the energy required to cover consumption is produced by renewable energy sources (42%, 47% and 53%), to which the energy stored in batteries (39%, 28% and 18%) is added.

In the current context of the transition toward climate neutrality and the pressing need to reduce energy consumption in the construction sector, nZEBs have become a central benchmark in European sustainability policies. These buildings offer multiple benefits, such as reduced operational costs, enhanced thermal comfort, and improved indoor air quality. Achieving such performance requires the integration of advanced technological solutions, including passive façades with ventilated cavities. The primary objective of this study is to investigate the influence of cavity geometry on the thermal behavior of a passive façade, through numerical simulations conducted in ANSYS Fluent 17. The study focuses on comparing five distinct configurations with varying cavity widths, aiming to identify the optimal solution in terms of heat transfer efficiency. The main contribution lies in the analysis and correlation of air temperature and velocity distributions with the cavity’s geometric parameters, highlighting the impact of channel width on thermal performance. The configuration with a 12 cm wide air channel recorded the highest heat flux at the outlet, approximately 44 times greater than the façade with a 4 cm wide channel, making it the most efficient solution. The results indicate significantly higher thermal efficiency for the configuration with a larger cavity width, contrary to initial intuitive assumptions. These insights provide a valuable framework for the optimal design of passive façades in nZEB applications and highlight the need for further research, combining numerical and experimental approaches, to develop sustainable and energy-efficient building envelope solutions.

The double-skin façade (DSF), referred to hereinafter as a passive façade, represents an alternative technology aimed at improving the energy performance of buildings with glass envelopes. A passive façade consists of a traditional façade supplemented on the interior by a secondary layer, which is separated by a ventilated cavity with a variable width. Numerous studies have been conducted to optimize the control of passive façades with the aim of improving building energy performance. This study focuses on comparing experimental data for the passive façade with numerical simulations conducted in ANSYS Fluent 17, proposing optimization options based on the analysis of temperature and velocity fields within the façade. The results reveal the dynamics of natural free convection within the passive façade, the presence of recirculation zones in the experimental model, and the manifestation of the “chimney effect” observed in the temperature analysis of the façade’s interior in both experimental and numerical models. ANSYS Fluent 17 is a numerical simulation software used extensively in engineering and research to provide precise and comprehensive solutions for complex fluid dynamics problems. Although there is a body of existing research, the need for further investigation into façade design, control, and optimization continues.

This paper presents a low speed drive system with a simple and reliable construction, which can be used in an area where there is no power supply (isolated areas, forests, agricultural fields, etc.) and which operates on the basis of two heat sources, one from solar radiation and one provided by water. Alternatively, this system can be used to recover energy from wastewater from industry. The operation and role of the parameters that can influence the value of the rotation speed of the drive system are analyzed through a simulation, maintaining a constant speed in the case of the prototype is achieved through the control system because in real situations the temperature of heat sources can vary within certain limits. The models and tests performed highlight the parameters of the analyzed drive system and the limits of the range in which its speed can vary.

Intelligent materials, especially materials with shape memory, are an important discovery, with technical applications in the medical and aerospace field, among others, which led to the development of systems and applications with multiple advantages and disadvantages due to ignorance about their functionality. This paper presents an application developed in the research laboratory for determining and monitoring the behavior of a material element with Ni-Ti shape memory, and its lifespan. The application allows the stress level of the Ni-Ti element subjected to numerous repeated cycles of deformation to be determined by supplying it to a constant electric current. Thus, the results show the variation of the Ni-Ti element force, in the form of a spring, at the ambient temperature variations as well as force variations at different numbers of attempts. The Ni-Ti alloy has both shape retention and superelasticity properties, being the most common in the fields of applicability. Due to its unique properties, it can be used in the most demanding applications in the medical field, usually involving difficult conditions of resistance to fatigue.