5 results on '"Michael, Frătița"'
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2. Assessment of Engine Performance and Emissions with Eucalyptus Oil and Diesel Blends
- Author
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Robert Mădălin Chivu, Jorge Martins, Florin Popescu, Margarida Gonçalves, Krisztina Uzuneanu, Michael Frătița, and Francisco P. Brito
- Subjects
biofuel ,eucalyptus oil ,sustainable diesel fuel alternatives ,engine performance and emissions ,Technology - Abstract
This research evaluates the feasibility of using eucalyptus oil blended with conventional diesel fuel in diesel engines. Eucalyptus globulus is one of the main tree species cultivated for paper pulp in western European countries such as Portugal, and eucalyptus oil is one of the byproducts that so far has not been sufficiently evaluated as a biofuel. This study assesses the impact of using this additive on engine performance parameters and emissions as a means to contribute to reducing fossil fuel consumption and pollutant and greenhouse gas (GHG) emissions. The analysis revealed that the addition of eucalyptus oil had a positive effect on torque, a critical performance parameter, with biofuel blends showing consistent torque increases at lower engine speeds. However, torque tended to decrease towards the higher range of engine speed for eucalyptus oil–diesel blends. Several blends showed lower brake specific fuel consumption compared to regular diesel at high engine loads and low engine speeds. Brake thermal efficiency did not vary substantially at lower engine speeds and loads but decreased at higher speeds and loads. Pollutant emissions, particularly unburned hydrocarbons and nitrogen oxides, were influenced by fuel composition, with biofuel blends showing both increases and decreases compared to diesel. It is noteworthy that eucalyptus oil blends exhibited up to a 60% reduction in smoke opacity under specific operating conditions at low speed and high load for 10% incorporation (10EU90D), suggesting that in addition to the already positive effects of cutting down fossil CO2 emissions in proportion to the substitution of fossil diesel with nearly carbon-neutral eucalyptus oil, more environmental benefits may be expected from the incorporation of this product. Although the present economic viability of using eucalyptus oil as a biofuel is still not guaranteed, the present study seems to reinforce its technical viability. Future prospects for the improvement of oil yield through biotechnology, the economic interest of this product for several countries, and the updating and upscaling industrial processes may allow the viability of this biofuel to remain a possibility in the future
- Published
- 2024
- Full Text
- View/download PDF
3. Energy Analysis of Waste Heat Recovery Using Supercritical CO2 Brayton Cycle for Series Hybrid Electric Vehicles
- Author
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Gabriel Mocanu, Cristian Iosifescu, Ion V. Ion, Florin Popescu, Michael Frătița, and Robert Mădălin Chivu
- Subjects
internal combustion engine ,waste heat ,supercritical CO2 recompression Brayton cycle ,heat recovery ,Technology - Abstract
Waste heat recovery from exhaust gas is one of the most convenient methods to save energy in internal combustion engine-driven vehicles. This paper aims to investigate a reduction in waste heat from the exhaust gas of an internal combustion engine of a serial Diesel–electric hybrid bus by recovering part of the heat and converting it into useful power with the help of a split-flow supercritical CO2 (sCO2) recompression Brayton cycle. It can recover 17.01 kW of the total 33.47 kW of waste heat contained in exhaust gas from a 151 kW internal combustion engine. The thermal efficiency of the cycle is 38.51%, and the net power of the cycle is 6.55 kW. The variation in the sCO2 temperature at the shutdown of the internal combustion engine is analyzed, and a slow drop followed by a sudden and then a slow drop is observed. After 80 s from stopping the engine, the temperature drops by (23–33)% depending on the tube thickness of the recovery heat exchanger. The performances (net power, thermal efficiency, and waste heat recovery efficiency) of the split-flow sCO2 recompression Brayton cycle are clearly superior to those of the steam Rankine cycle and the organic Rankine cycle (ORC) with cyclopentane as a working fluid.
- Published
- 2024
- Full Text
- View/download PDF
4. Heat requirement in an indoor recirculating aquaculture system
- Author
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Ion V. Ion, Florin Popescu, Gelu Coman, and Michael Frătița
- Subjects
Biomass boiler ,Heat pump ,Heating ,Indoor recirculating aquaculture ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Due to the benefits of the recirculating aquaculture system (RAS), many fish farmers are choosing this system. Some farmers chose indoor RAS, where fish tanks are kept inside buildings or greenhouses. Heating the buildings and the makeup water requires a substantial amount of energy since optimum growth temperatures exceed the normal temperature of supply water. In this paper three different heating systems are analyzed: ground source heat pump, natural gas boiler and wood pellet boiler. The annual running cost of the water heating system in both cases (with heat recovery and no heat recovery) is the lowest for the ground source heat pump, followed by the wood pellet boiler and the natural gas boiler.
- Published
- 2022
- Full Text
- View/download PDF
5. RENEWABLE ENERGY - FLOATING SOLAR FARMS IN ROMANIA.
- Author
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Michael, Frătița, Eugen, Rusu, Florin, Popescu, Ion, Ion, and Razvan, Mahu
- Subjects
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SOLAR power plants , *RENEWABLE energy sources , *GEOGRAPHICAL positions , *DATABASES , *SURFACE area - Abstract
The paper presents the possibility of floating photovoltaic farms on the reservoirs of the Olt river in Romania. For the analysis, a database with the solar irradiance evolution for one year in the four possible locations was created, using the PVGIS-SARAH2 database. The locations were chosen according to the surface area of the reservoir, geographical position, and possibility of connection to the national energy system. After the analysis, it was observed that during the cold season, the solar irradiance is higher in locations 1 and 2, while locations 3 and 4 show higher irradiance during the warm season. Simulations of electricity production were carried out for the location of solar farms, with an installed capacity of 1 MWh, with a southern positioning of the panels having different tilt angles of: 0, 15, 30 and 45 degrees. The paper continues with a statistical analysis of the monthly and annual electricity production when installing solar farms in the analysed locations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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