School and school gym buildings represent a relevant potential for construction of photovoltaic panels, to be integrated into roofs of these buildings. Given that roof structures are passive, ...construction of photovoltaic systems does not interfere with the building functionality, does not it in any way adversely affect the environment. Installation of photovoltaic systems on building roofs brings the production and consumption of electricity closest possible, therefore such systems ensure significant reduction in power losses in transmission and distribution grids. In addition to locally produced electricity, construction of photovoltaic systems on the school buildings’ roofs produces an educational effect as well. By installing a measuring and acquisition system which would include the measuring data on the photovoltaic power plant production parameters and school electricity consumption into school labs, technology would be closer to students, as well as possibilities to meet the demand for electricity from this basic renewable energy source. This paper presents the results of evaluations of the available roof surfaces of school buildings in Serbia for the photovoltaic panels installation. For each category of school building, an estimate of possible annual production per unit of average roof area was made. Summarizing all the results, estimates of possible installed capacity and annual electricity production for different scenarios are given.
One of the biggest problems related to mandatory tanks of oil and oil derivatives are evaporative losses in the tanks. It is well known that the storage, manipulation, and transport of oil and oil ...derivatives results in the evaporation of the liquid. In the case of tanks where commodity reserves are stored for a long period of time, the most pronounced problems are ?breathing? losses and degradation of the quality of petroleum products. Many of these volatile organic compounds also have a strong negative impact that is harmful to human health and the environment. The aim of this research is to improve system in order to reduce evaporative losses in the tanks which are used for mandatory reserves of oil and oil derivative in warehouse in location near Pozega in Serbia as well as to reduce the harmful impact on the environment with the proposed improvement measures.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The roofs of residential buildings represent a relevant potential for the construction of photovoltaic panels. Given that roof structures are passive, the construction of photovoltaic systems on ...residential buildings does not interfere with the functionality of the building, nor do they affect the environment in any other way. By installing photovoltaic systems on the roofs of residential buildings, the production and consumption of electricity are brought closer to the maximum possible extent, so such systems ensure a significant reduction of electricity losses in the distribution and transmission network. This paper presents the results of research aimed at establishing a framework for decentralized and decarbonized production of electricity from photovoltaic systems integrated into the roofs of residential buildings in Serbia, through the support of the prosumer approach. For each defined category of residential building in Serbia, the possible annual production of electricity per unit of average roof area was estimated. Summarizing all the results, assessments of the possible installed capacity of photovoltaic systems and annual electricity production at the national level were made.
For each photovoltaic power plant, it is extremely important to perform an analysis of its efficiency, as well as an analysis of all parameters that may affect efficiency. The electric energy of the ...photovoltaic system, which is delivered to the electric power system on a daily basis, is determined through the average daily insolation, the surface of the panel and the average efficiency value. One of the parameters that affect the conversion efficiency of a photovoltaic power plant is a decrease in the conversion efficiency due to an increase in panel temperature. In this paper an example is a real photovoltaic power plant with a nominal power of 50 kW, which is installed on the rooftop of the building of the Institute "Mihajlo Pupin", located in Zvezdara forest, Belgrade, Serbia. The correlation analysis of the estimated temperature of the photovoltaic panel was performed using two models and the measured temperature of the photovoltaic panel. The temperature of the photovoltaic panel was estimated using models, one of which does not take into account, and the other takes into account the influence of wind speed on the temperature of the panel.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Jedan od mogućih pravaca dekarbonizacije i elektrifikacije teretnog i putničkog transporta je upotreba gorivnih ćelija sa vodonikom kao pogonskim gorivom. S obzirom da je primena biomase za ...proizvodnju električne energije u velikoj meri nekonkurentna u odnosu na vetroelektrane i solarne elektrane, njena primena za dobijanje vodonika predstavlja jedan od mogućih pravaca razvoja ovog obnovljivog izvora energije. U ovom radu su analizirane tehnologije za proizvodnju vodonika iz biodizela. Izvršena je analiza strukture i ukupnih troškova proizvodnje vodonika iz biodizela, kao i energetski bilans ovog procesa. Sagledani su uslovi korišćenja vodonika za pogon gorivnih ćelija u električnim vozilima. Sprovedena je analiza efikasnosti energetskog ciklusa: biodizel – vodonik – električna energija – mehanička energija za pogon električnih vozila. Kao krajnji rezultat izvršena je procena troškova proizvodnje kWh električne energije iz biodizela i uporedna analiza sa vozilom koje je pogonjeno dizel motorom i električnim motorom napajanim iz baterija.
One of the possible directions of decarbonisation and electrification of freight and passenger transport is the use of fuel cells with hydrogen as a fuel. Considering that the use of biomass for ...electricity generation is largely uncompetitive compared to wind and solar power plants, its use for hydrogen production is one of the possible directions of development of this renewable energy source. In this paper, technologies for hydrogen production from biodiesel were analyzed. An analysis of the structure and total costs of hydrogen production from biodiesel was performed, as well as the energy balance of this process. The conditions of using hydrogen to drive fuel cells in electric vehicles were considered. The efficiency of the energy cycle analysis was performed: biodiesel - hydrogen - electricity - mechanical energy to drive electric vehicles. As a final result, an estimation of the costs of production of kWh of electricity from biodiesel and a comparative analysis with a vehicle powered by a diesel engine and an electric motor powered by batteries was performed.
Preschool buildings represent a relevant potential for construction of photovoltaic panels, to be integrated into roofs of these buildings. Given that roof structures are passive, construction of ...photovoltaic systems does not interfere with the building functionality, does not it in any way adversely affect the environment. Installation of photovoltaic systems on building roofs brings the production and consumption of electricity closest possible, therefore such systems ensure significant reduction in power losses in transmission and distribution grids. In addition to locally produced electricity, construction of photovoltaic systems on the preschool buildings' roofs produces an educational effect as well. This paper presents the results of evaluations of the available roof surfaces of preschool buildings in Serbia for the photovoltaic panels installation. For each category of preschool building, an estimate of possible annual production per unit of average roof area was made. Summarizing all the results, estimates of possible installed capacity and annual electricity production for different scenarios are given.
In order to shed light on the intrapersonal mechanisms that underlie the teaching in the blended learning environment, which implies the integration of complementary face-to-face and online ...approaches, we focused on the relationship between teachers’ self-efficacy and motivation for teaching, with reference to the mediating role of teachers’ emotional experiences. The sample included 341 subject teachers from Serbian primary schools, who use the blended learning model in teaching (84% female; average age 43.97 years). The Teachers’ Sense of Efficacy Scale, Emotions in Teaching Inventory – Revised, and Autonomous Motivation for Teaching Scale were used to examine the variables of interest. The overall fit of the mediated model to the data was adequate, confirming the mediating role of teachers’ emotions in the relationship between the studied motivational constructs. The results indicate that the motivation for teaching in a blended learning environment relies on self-efficacy in instructional strategies and self-efficacy in classroom management, which partially act through the emotions concerning the experience of tension.
