In this paper, the authors propose a case study on the energy efficiency of a house built in accordance with sustainable development directions. Thus, the envelope is made of ecological materials, namely the resistance structure and finishes are made of wood, and the thermal insulation of sheep's wool. It is a modular, prefabricated house, designed so that energy consumption is reduced both in the construction and exploitation phase. Having a built area of 31.5 m2, it can be used as a residential house or a holiday home. For this, the thermotechnical properties of the envelope elements were studied.

Keywords: ecological construction, energy efficiency, envelope structure, thermal resistance, heat transfer coefficient, thermal stability, water vapor permeability

Vitroceramica celulara a fost produsa prin sinterizare la 850-860 ºC utilizand, ca materie prima principala, cenușa zburatoare de carbune (74-79 %), un produs secundar industrial, borax (20-25 %), ca agent de fluidizare si carbonat de calciu (1 %), ca agent de spumare clasic. Originalitatea lucrarii a fost aplicarea tehnicii neconventionale, rapida si economica, a incalzirii directe cu microunde. Această tehnica nu este utilizata in procese similare industriale. Rezultatele au aratat rezistenta foarte mare la compresiune (11,7-18,3 MPa), proprietati termoizolante bune, adecvate pentru aplicatii in constructie si consum specific de energie foarte redus (0,50-0,60 kWh/kg).

Cuvinte cheie: vitroceramica celulara, incălzire directa cu microunde, cenusa zburatoare de carbune, borax, rezistenta la compresiune

Cellular glass-ceramic was produced by sintering at 850-860 ºC using, as the main raw material, coal fly ash (74-79 %), an industrial by-product, borax (20-25 %,) as a fluxing agent and calcium carbonate (1 %), as a classic expanding agent. The originality of the work was the application of the unconventional, fast and economical technique of direct microwave heating. This technique is not used in similar industrial processes. The results showed very high compressive strength (11.7-18.3 MPa), good thermal insulation properties, suitable for building applications and very low specific energy consumption (0.50-0.60 kWh/kg).

Keywords: cellular glass ceramics, direct microwave heating, coal fly ash, borax, compressive strength.

Cresterea consumului de energie si al emisiilor de gaze cu efect de sera (GES) are consecinte din ce in ce mai grave asupra mediului, societatii si economiei, atat la nivel global, european, cat si national. In acest context lupta pentru masuri de combatere a efectelor schimbarilor climatice impune stabilirea de strategii energetice si ecologice. La nivel european s-a stabilit neutralizarea emisiilor de gaze cu efect de sera pana in 2050, imbunatatirea eficientei energetice si promovarea surselor regenerabile de energie. Utilizarea resurselor eoliene, in special a turbinelor eoliene cu generatoare sincrone cu magneti permanenti si a diverselor actuatoare electrice avansate - convertoare de mare putere, se accentueaza tot mai mult. Aceasta lucrare este un studiu bibliografic elaborat al compozitiei, tehnologiilor si configuratiilor de ultima generatie a lantului de energie eoliana a unui parc eolian. Sunt abordate si studiate tendințele actuale ale diferitelor topologii din lantul de conversie a energiei eoliene disponibile in literatura.

Cuvinte cheie: actuatoare electrice avansate, conversie de energie, configuratie electrica

The increase in energy consumption and emissions of greenhouse gases (GHG) has increasingly serious consequences on the environment, society and the economy, both at the global, European and national level. In this context, the fight for measures to combat the effects of climate change require the establishment of energy and ecological strategies. At the European level, the neutralization of greenhouse gas emissions by 2050, the improvement of energy efficiency and promotion of renewable energy sources have been established. The use of wind resources, especially wind turbines with permanent magnets synchronous generators and various advanced electrical actuators - high power converters, is increasingly emphasized. This paper is an elaborate bibliographic study of the state-of-the-art wind power chain composition, technologies and configurations of a wind farm. The current trends of the different topologies in the wind power conversion chain available in the literature are addressed and studied.

Keywords: advanced electric actuators, energy conversion, electrical configuration.

Providing the required indoor comfort at minimal operating costs is the main objective of every HVAC system. However, despite the fact that in theory, each design effort promises to deliver the design flow at each heating or cooling unit, in reality this is not happening too often. The role of balancing is to obtain the design flow at each terminal unit, by installing some specialized valves and applying a coherent procedure of setting and adjustment. This paper presents a simple hydronic balancing simulator, implemented in a Microsoft Excel spreadsheet. The model uses static STAD balancing valves, provided by the Swedish manufacturer Tour Andersson. The main purpose of the simulator is to obtain a learning tool for students or young engineers, allowing them to observe and understand the circuits interactions when running balancing procedures

Keywords: hydronic balancing, simulator, Excel, balancing valves, Tour Andersson

FDS is the software researchers use to simulate the evolution of a fire inside the buildings or to simulate exterior fires. FDS was used in research on modelling of the fire inside a room with dimensions of 3(m) x 6(m) x 2.7(m). The research included an experimental study and a computer modelling component to expand the probable scenarios. The research concludes that the FDS software can allow proper modelling of fire evolution, but an important stage is a phase of determining the model and calibrating it. Entering the input data correctly is an extremely important step

Keywords: FDS, CFD, fire, temperature, construction

Consumul mondial in continua crestere de gaze naturale si rapiditatea epuizarii rezervelor de combustibili fosili au tras un semnal de alarma specialistilor preocupati de cautarea unor solutii energetice care sa raspunda nevoilor actuale, pentru o crestere economica sustenabila. Lucrarea de fata prezinta accesul biometanului in sistemele existente de distributie a gazelor naturale, cu scopul diminuarii consumului de combustibili fosili. Acest articol investigheaza indicatori specifici pietei de gaze naturale din Romania, avand drept tinta identificarea unei solutii eficiente privind suplimentarea de combustibili mai putini nocivi decat combustibilii fosili, biometanul fiind o alternativa regenerabila la combustibilii fosili. In acest caz, gazul „verde ” - biometanul ajunge la utilizatorii finali prin intermediul conductelor de distributie existente.

Cuvinte cheie: gaze naturale, energie regenerabila, biometan, sistem distribuție, sustenabilitate

The ever-increasing global consumption of natural gas and the rapid depletion of fossil fuel reserves have sounded the alarm to those concerned with finding energy solutions that meet current needs for sustainable economic growth. This paper presents the access of biomethane in existing natural gas distribution systems, in order to reduce the consumption of fossil fuels. This article investigates specific indicators of the Romanian natural gas market, aiming to identify an efficient solution for supplementing less harmful fuels than fossil fuels, biomethane being a renewable alternative to fossil fuels. In this case, the „green” gas - biomethane reaches the end users through the existing distribution pipes.

Keywords: natural gas, renewable energy, biomethane, distribution system, sustainability

This paper focus on biomechanical models analysis of human body from one to five degree of freedom. As result of this analysis the medium frequencies of different human body elements are found.

Keywords: vibrations, human body, biomechanical models