António Domingues - Academia.edu (original) (raw)
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Papers by António Domingues
Energy, 2013
With increasing oil prices and growing interest in cutting emissions of greenhouse gases, waste h... more With increasing oil prices and growing interest in cutting emissions of greenhouse gases, waste heat recovery techniques based in Rankine cycle systems, appear as a very promising path to enhance the thermal efficiency of internal combustion engines (ICE). This study evaluates the potential use of thermal energy contained in exhaust gases of vehicles equipped with ICEs. It was developed a numerical model for the thermodynamic analysis of a Rankine cycle that uses waste heat contained in the exhaust gases of an ICE. All characteristics related to a tubular heat exchanger have been incorporated in the thermodynamic model. For the simulations, it was used experimental results obtained in a vehicle tested on a chassis dynamometer. The thermodynamic analysis was performed for the following working fluids: water, R123 and R245fa. The results reveal the advantage of using water as the working fluid in applications of thermal recovery from exhaust gases of vehicles equipped with a spark-ignition engine. The simulations reveal increases in thermal efficiency and mechanical efficiency of around 3% and 16%, respectively, when using an ideal heat exchanger. Considering a tubular heat exchanger, the simulations show an increase of 1.2% in the thermal efficiency and an increase of 5.4% in the mechanical efficiency for an evaporating pressure of 2 MPa. The results confirm the advantages of the use of the thermal energy contained in the exhaust gases through a co-generation application of the Rankine cycle in vehicles.
Energy, 2013
With increasing oil prices and growing interest in cutting emissions of greenhouse gases, waste h... more With increasing oil prices and growing interest in cutting emissions of greenhouse gases, waste heat recovery techniques based in Rankine cycle systems, appear as a very promising path to enhance the thermal efficiency of internal combustion engines (ICE). This study evaluates the potential use of thermal energy contained in exhaust gases of vehicles equipped with ICEs. It was developed a numerical model for the thermodynamic analysis of a Rankine cycle that uses waste heat contained in the exhaust gases of an ICE. All characteristics related to a tubular heat exchanger have been incorporated in the thermodynamic model. For the simulations, it was used experimental results obtained in a vehicle tested on a chassis dynamometer. The thermodynamic analysis was performed for the following working fluids: water, R123 and R245fa. The results reveal the advantage of using water as the working fluid in applications of thermal recovery from exhaust gases of vehicles equipped with a spark-ignition engine. The simulations reveal increases in thermal efficiency and mechanical efficiency of around 3% and 16%, respectively, when using an ideal heat exchanger. Considering a tubular heat exchanger, the simulations show an increase of 1.2% in the thermal efficiency and an increase of 5.4% in the mechanical efficiency for an evaporating pressure of 2 MPa. The results confirm the advantages of the use of the thermal energy contained in the exhaust gases through a co-generation application of the Rankine cycle in vehicles.