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In this study, the performance of conventional aircraft using fossil-fuels and batterypowered aircraft was analyzed and compared within the framework of transitioning to all-electric aircraft. Electric aircraft are propelled by electric motors that drive the propellers using electricity as their power source. These aircraft produce zero direct emissions during flight, reduce noise pollution, and exhibit higher energy efficiency compared to combustion engines. However, before electric aircraft can be fully developed, several challenges related to battery technology must be addressed. Battery-powered aircraft currently cannot match the endurance, altitude, and range capabilities of jet fuel-powered aircraft due to the limited battery capacity imposed by today's technology. Current battery technologies have lower energy density compared to aviation fuels, resulting in shorter flight ranges and limited energy storage capacity. Presently, jet fuel exhibits a specific energy of approximately 12000 Wh/kg with an engine efficiency of 25-35%. In contrast, batteries possess an energy density of about 250-400 Wh/kg with an electric motor efficiency of 90- 96%. This indicates that jet fuel is roughly 30-50 times more energy-dense than batteries. To achieve parity in energy density, a significantly greater number of batteries would need to be added to the aircraft, resulting in a substantial increase in weight. However, due to the lower efficiency of fossil fuel engines, battery energy density does not have to reach the level of jet fuel (12000 Wh/kg) to match the flight range. Calculations indicate that, in order to fully utilize all-electric aircraft in the future, batteries should reach at least 40-50% of fuel energy density to match the performance of current turbofan aircraft. [ABSTRACT FROM AUTHOR]

In this study, the effect of inlet air cooling on greenhouse gas (GHG) emissions and engine performance for a land-based gas turbine engine was investigated under varying ambient temperatures (15–55 °C). The study aimed to reduce GHG emissions while improving output power and fuel efficiency during hot weather operating conditions. For illustrative purposes, a representative gas turbine engine model, approximating the 250 MW class General Electric (GE) engine, was analyzed in a simple cycle. A refrigeration process was integrated with a turboshaft gas turbine engine to chill the incoming air, and the power required for cooling was extracted from the gas turbine's output power. This mechanical chiller was assumed to provide a 15 °C inlet air temperature. Without inlet air cooling, at 55 °C ambient temperature, the engine's power output was calculated to decrease by 15.06%, while power-specific fuel consumption and GHG emissions increased by 6.09% and 5.84%, respectively. However, activating the refrigeration or cooling system in the inlet made it possible to mitigate most of the adverse effects of hot weather on the engine's performance and GHG emissions. Therefore, with inlet air cooling, the power output loss reduces to 3.28%, indicating an 11.78% recovery compared to the 15.06% loss without cooling. Similarly, the rise in power-specific fuel consumption caused by high ambient temperature decreases from 6.09% to 3.43%, reflecting a 2.66% improvement. An important finding of the study is that with inlet air cooling, the increase in GHG emissions reduces from 5.84% to 3.41%, signifying a 2.43% improvement on a hot day with a temperature of 55 °C. [ABSTRACT FROM AUTHOR]