Proposals to energy efficiency cooling processes and hot water preparation in buildings located near surface water sources |
| Author : Adriana Tokar, Marius Adam, Daniel Bisorca, Cristian Pacurar, Alexandru Dorca, Danu? Tokar, Daniel Muntean |
| Abstract | Full Text |
Abstract :The article aims to present in general terms a concept that can be applied to streamline the cooling and hot water preparation processes in buildings located near surface water sources. The proposed solutions use logical principles, available equipment and are economically accessible from the point of view of cost-benefit analysis |
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The choice of electricity storage systems to optimize the load curve. Case studies |
| Author : Danut Tokar, Adriana Tokar, Daniel Muntean, Daniel Bisorca, Alexandru Dorca, Marius Adam |
| Abstract | Full Text |
Abstract :The European Commission s (EC) policy to phase out fossil fuels from the energy system has forced the reconfiguration of electricity systems (ESS) as a result of the large-scale introduction of renewable energy systems (RES). Achieving these objectives while ensuring energy security must lead to a balanced energy mix capable of ensuring an energy price that can be borne by end consumers, a goal that can be achieved by installing energy storage systems |
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Study on the parameters influencing the bending and shear behavior of steel fiber reinforced concrete elements |
| Author : Muheeb Altaleb, Andrei Gîrboveanu, Dan Georgescu, Amine Rahaoui |
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Abstract :Different types of fibers can be used to improve the mechanical behavior of steel fiber reinforced concrete. However, the degree to which this occurs also depends on certain characteristics of the structural element section. This paper studies the effects of adding fibers on the bending moment and shear force resistance depending on the geometry of the transversely unreinforced section, but also on the amount of longitudinal reinforcement. The results show a significant increase of the resisting moments for a high fiber content and reduced longitudinal reinforcement, but also a significant increase of the resisting shear force for a high fiber content, regardless of the amount of longitudinal reinforcement |
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Effects of Bitumen Content on the Quality of Asphalt Used for the Construction of Flexible Pavements |
| Author : Olufikayo Aderinlewo, Israel Olabode, Funso Orogbangba, Sunday Akinte, Matthias Abraham |
| Abstract | Full Text |
Abstract :Road pavements in Nigeria and other developing regions are often faced with premature failures due to suboptimal asphalt mix designs, particularly related to bitumen content (5%, 6%, 7% and 8%) as this affects the mechanical and durability properties of asphalt used for flexible pavement construction. Laboratory tests, including penetration, ductility, viscosity, flash and fire points, Marshall Stability, flow, bulk density, air voids and drying shrinkage tests were conducted. The results indicate that an optimum bitumen content of approximately 6.67% provides the best balance of stability, density and durability. Higher contents lead to excessive deformation and rutting, while lower contents result in inadequate cohesion and strength. These findings highlight the importance of adequate mix design to enhance pavement performance and longevity in similar conditions |
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Latest solutions in optimizing electrical energy consumption in water supply systems Water losses in the water supply system |
| Author : Drago? – Vasile Ille, Coita Flaviu-Glad, George – Lucian Ionescu |
| Abstract | Full Text |
Abstract :The main source of energy loss within water supply systems is found within the loss of water from within said systems.Understanding the reasons for these losses and taking the proper steps in curtailing their occurence while also reinforcing the reliability of the systems will ensure not only the optimal operational regime for the system but also increase the energy economy |
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Engineered Cementitious Composites (ECC): A Review of the Most Common Laboratory Testing Methods |
| Author : Ioan ?tefan Zavaschi, Calin Grigore Radu Mircea, Tudor Panfil Toader |
| Abstract | Full Text |
Abstract :Recent advancements in material research and technological innovations in the processing of raw materials for concrete production, combined with global shifts and the pursuit of sustainability, have prompted increased interest in the development of novel concrete mixtures. Despite several decades of intensive research in concrete technology, the practical implementation of these advancements remains relatively limited. This paper reviews existing testing methods and synthesizes the most relevant findings, while emphasizing the specific contributions and limitations of each study |
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Vegetable origin-natural fibres for reinforcement of geopolymer composite |
| Author : Lucian Paunescu, Enikö Volceanov, Adrian Ioana, Bogdan Valentin Paunescu |
| Abstract | Full Text |
Abstract :The current trend to decrease greenhouse gas emissions through increasing the efficiency of fossil fuel consumption implies the use of lighter materials in building construction, with a lower carbon footprint compared to materials commonly applied in the present. Composites prepared from vegetable fibres constitute a viable solution to reach this objective. The precursors adopted for the production of the geopolymer composite were fly ash, granulated blast furnace slag, and rice husk ash, as aluminasilicate materials with cementitious properties, to which hemp fibres were added with a major role in reinforcing the composite. Results showed increasing the compression and flexure strength |
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Comparative Analysis of a Photovoltaic System’s Performance: Simulation vs. Reality |
| Author : Norbert Gocz |
| Abstract | Full Text |
Abstract :This paper provides a comparative analysis of the estimated versus actual energy production of a residential photovoltaic system installed on a single-family home. The aim is to assess the accuracy of simulations conducted using PV*Syst and PVGIS software, using different climatic data sources. The system under study has a total installed capacity of 6.56 kWp and it is equipped with monocrystalline panels and an ongrid inverter. By comparing the simulated results with real data recorded monthly, the differences between the estimated and observed performance during operation are highlighted. The findings emphasize the importance of validating simulations through practical measurements and the relevance of selecting appropriate meteorological data for accurately sizing a photovoltaic system and estimating the return on investment |
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The concept of an installation for testing, monitoring and efficient management of complex systems equipped with a heat pump for heating / cooling and preparing hot water in buildings |
| Author : Daniel Bisorca, Adriana Tokar, Danut Tokar, Daniel Muntean, Alexandru Dorca |
| Abstract | Full Text |
Abstract :The article presents proposals for energy efficiency of complex heating/cooling and domestic hot water systems by conceptualizing two systems for energy-efficient testing and management applied to a mixed ensemble consisting of two water-to-water and air-to-water heat pumps, respectively |
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Evaluation of algae drying process using a solar air dryer built from recycled materials |
| Author : Rafaela Pontes, Razvan Calota, Charles Berville, Paul Danca |
| Abstract | Full Text |
Abstract :This article presents a preliminary evaluation of a low-cost solar drying system, built entirely from recycled materials and tested for marine biomass applications. The experiment was set up using an air solar collector constructed from a reused window frame and a drying chamber housed inside a repurposed refrigerator. Tests were conducted on commercial wakame (Undaria pinnatifida) under forced convection, using a solar simulator with 2.0 kW halogen lamps. After 3.75 hours of system operation, a 47.2% reduction in mass was observed, from 477.7 g to 252.3 g. The recycled collector raised the drying air temperature by about 14...15°C above ambient, with a peak of 33.9°C and an air velocity of 0.5...0.6 m/s. The results show that the system is promising, but insulation and airflow need improvement to increase even further the drying air temperature |
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Considerations regarding the impact of artificial lighting on health |
| Author : Iasmina-Daiana Holecica, Andreea-Miruna Tokar, Danut Tokar |
| Abstract | Full Text |
Abstract :The article presents quantitative and qualitative aspects of lighting, its influence on activities carried out in educational and health spaces, and the impact of artificial lighting through its effects, especially blue light, on health |
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Study of variable refrigerant flow systems: an alternative to traditional air conditioning |
| Author : Iulian Enaru, Marius-Costel Balan, Andrei Burlacu, Robert Stefan Vizitiu, Stefanica Eliza Tansanu |
| Abstract | Full Text |
Abstract :Variable refrigerant flow systems offer significant advantages over traditional air conditioning systems. They enable individual temperature control for each indoor unit, providing superior comfort compared to the uniform settings of conventional systems. VRF optimizes energy efficiency by adjusting the refrigerant flow according to overall demand, thus preventing excessive energy consumption. Due to their scalability and easier integration into modern buildings, VRF systems represent a highly efficient and adaptable solution for contemporary climate control |
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Prospects for sustainable development of the energy sector in the Republic of Moldova through energy efficiency programs and projects |
| Author : Alexandrina Berzerdeanu, Mihai Lupu, Galina Uzun, Vasile Daud |
| Abstract | Full Text |
Abstract :The paper analyzes the impact of the EcoVoucher Program on the sustainable development of the energy sector in the Republic of Moldova. Launched in November 2023 with the support of UNDP (United Nations Development Programme) Moldova and funded by the European Union, through the former Energy Efficiency Agency-now the National Center for Sustainable Energy (CNED) -the program aimed to support vulnerable households in replacing old household appliances with modern, energy-efficient ones. During the pilot stage, carried out between October 2023 and July 2024, a total of 198,685 vouchers were distributed, of which 39,084 were redeemed, resulting in annual energy savings of approximately 1.6 million kWh or 7 million MDL, and contributing to a reduction of over 830 kg of CO2 emissions annually. Subsequently, the program was fully taken over by CNED, which in 2024 issued 17,305 vouchers, of which 7,223 were used, achieving additional savings of 1.5 million kWh or 6.6 million MDL, and contributing to a reduction of 789.6 kg of CO2 emissions annually |
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Analysis of the computer simulation for optimizing the evacuation of people in an event hall |
| Author : Emanuil-Petru Ovadiuc, Razvan Calota, Ilinca Nastase, Ion Anghel, Manuel Serban |
| Abstract | Full Text |
Abstract :The article presents the development and analysis of an evacuation simulation for the ground floor of a building intended for conferences and events, using geometric modeling in SketchUp and occupant behavior simulation in Pathfinder. A total of 31 rooms and 41 doors (11 used as evacuation exits) were defined, along with a population of 524–526 occupants, assigned with variable profiles regarding speed, behavior, and anthropometric dimensions. Three scenarios were analyzed: normal evacuation, evacuation including persons with disabilities and one blocked exit, and a severe scenario with seven exits unavailable. The results show increases in evacuation time up to 121.8 seconds and the occurrence of congestion zones caused by uneven occupant distribution and reduced evacuation paths. The study highlights the importance of redundancy in evacuation routes, optimal furniture arrangement, and assistance for vulnerable individuals |
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