The analysis of acoustic emissions generated by the interaction between the wind and a building’s facade of approximately 90 m high, located in the city of Montevideo, is presented. There is a helipad on the roof of ...The analysis of acoustic emissions generated by the interaction between the wind and a building’s facade of approximately 90 m high, located in the city of Montevideo, is presented. There is a helipad on the roof of the building. It is surrounded by a perforated plate (4.87 m high). Once the building was finished, complaints about the noise annoyance were expressed by some neighbors and working population in the building. Measurements of sound pressure levels on the site have been done. Also the possible acoustic sources were physically characterized. The noise source was identified: the acoustical emissions were associated with a phenomenon caused by wind speeds above 20 m/s from different directions, generating high sounds pressure levels in octave band of 4000 Hz, after its passage through the perforated plate on the contour of the roof. These studies were complemented by measurements in wind tunnel using a physical model built with the same plate installed in the building, which allowed verifying the results.展开更多
This paper attempts to present some registers of sound pressure levels during the operation of large diesel engines (10 MW). During these registers we have found the preparation, occurrence and ending of events of the...This paper attempts to present some registers of sound pressure levels during the operation of large diesel engines (10 MW). During these registers we have found the preparation, occurrence and ending of events of thermoacoustic instability. They appear after a loosing of chaos period or a reduction in fluctuations in some frequencies. The most interesting phenomena were registered at low frequencies. However, they were accompanied by variations in sound emissions at medium and high frequencies. As there has been very little published data concerning these phenomena at real scale, it is imperative to point out that every quasi-stationary state we have measured during these episodes has lasted some minutes, significantly much more time than that of lab scale results.展开更多
Estimating CO2 emission factor of the electricity system is a key aspect in the calculation of the baseline emissions for projects certified as CDM （Clean Development Mechanism）, which replace energy from the grid. ...Estimating CO2 emission factor of the electricity system is a key aspect in the calculation of the baseline emissions for projects certified as CDM （Clean Development Mechanism）, which replace energy from the grid. Currently, Uruguay is driving the expansion of the electricity system based on domestic renewable energies, in addition to replacing oil-based fuels for others with lower emission factors. This implies a substantial change of the generation park in the next decade and of the associated CO2 emissions. In this paper, a calculation methodology of the baseline emissions is adapted for its incorporation in the software SimSEE （Electric Energy Systems Simulator）, which is used for modeling the Uruguayan electric system, and therefore, allows modeling the current energy generator park and the future one. Using this tool, the CO2 emission factor＇s evolution is evaluated in the 2012-2020 period. The 2020 scenario is based on an optimal expansion of the electric system. The results indicate a strong reduction of the emission factor between 2012 and 2020, going from average values （for 100 simulations） around 0.60 tCO2/MWh to 0.15 tCO2/MWh. In this possible future scenario, CDM certification will probably not act as a strong incentive in Uruguay for the development of projects based on non-traditional renewable energies.展开更多
文摘The analysis of acoustic emissions generated by the interaction between the wind and a building’s facade of approximately 90 m high, located in the city of Montevideo, is presented. There is a helipad on the roof of the building. It is surrounded by a perforated plate (4.87 m high). Once the building was finished, complaints about the noise annoyance were expressed by some neighbors and working population in the building. Measurements of sound pressure levels on the site have been done. Also the possible acoustic sources were physically characterized. The noise source was identified: the acoustical emissions were associated with a phenomenon caused by wind speeds above 20 m/s from different directions, generating high sounds pressure levels in octave band of 4000 Hz, after its passage through the perforated plate on the contour of the roof. These studies were complemented by measurements in wind tunnel using a physical model built with the same plate installed in the building, which allowed verifying the results.
文摘This paper attempts to present some registers of sound pressure levels during the operation of large diesel engines (10 MW). During these registers we have found the preparation, occurrence and ending of events of thermoacoustic instability. They appear after a loosing of chaos period or a reduction in fluctuations in some frequencies. The most interesting phenomena were registered at low frequencies. However, they were accompanied by variations in sound emissions at medium and high frequencies. As there has been very little published data concerning these phenomena at real scale, it is imperative to point out that every quasi-stationary state we have measured during these episodes has lasted some minutes, significantly much more time than that of lab scale results.
文摘Estimating CO2 emission factor of the electricity system is a key aspect in the calculation of the baseline emissions for projects certified as CDM （Clean Development Mechanism）, which replace energy from the grid. Currently, Uruguay is driving the expansion of the electricity system based on domestic renewable energies, in addition to replacing oil-based fuels for others with lower emission factors. This implies a substantial change of the generation park in the next decade and of the associated CO2 emissions. In this paper, a calculation methodology of the baseline emissions is adapted for its incorporation in the software SimSEE （Electric Energy Systems Simulator）, which is used for modeling the Uruguayan electric system, and therefore, allows modeling the current energy generator park and the future one. Using this tool, the CO2 emission factor＇s evolution is evaluated in the 2012-2020 period. The 2020 scenario is based on an optimal expansion of the electric system. The results indicate a strong reduction of the emission factor between 2012 and 2020, going from average values （for 100 simulations） around 0.60 tCO2/MWh to 0.15 tCO2/MWh. In this possible future scenario, CDM certification will probably not act as a strong incentive in Uruguay for the development of projects based on non-traditional renewable energies.
