Current industry trends demonstrate aircraft electrification will be part of future platforms in order to achieve higher levels of efficiency in various vehicle level subsystems. However electrification requires a substantial change in aircraft design that is not suitable for re-winged or re-engined applications as some aircraft manufacturers are opting for today. Thermal limits arise as engine cores progressively get smaller and hotter to improve overall engine efficiency [8] , while legacy systems still demand a substantial amount of pneumatic, hydraulic and electric power extraction. The environmental control system (ECS) provides pressurization, ventilation and air conditioning in commercial aircraft [7] , making it the main heat sink for all aircraft loads with exception of the engine. To mitigate the architecture thermal limits in an efficient manner, the form in which the ECS interacts with the engine will have to be enhanced as to reduce the overall energy consumed and achieve an energy optimized solution.This study examines a tradeoff analysis of an electric ECS by use of a fully integrated Numerical Propulsion Simulation System (NPSS) model that is capable of studying the interaction between the ECS and the engine cycle deck. It was found that a peak solution lays in a hybrid ECS where it utilizes the correct balance between a traditional pneumatic and a fully electric system. This intermediate architecture offers a substantial improvement in aircraft fuel consumptions due to a reduced amount of waste heat and customer bleed in exchange for partial electrification of the air-conditions pack which is a viable option for re-winged applications. iii iv Para Dayana, Isaac y Ofelia v vi Acknowledgements I would first like to thank my wife, Dayana, for all her encouragement, support and patience, without her this paper would have not been possible. Her love was ever present, driving me to successfully completing my dissertation, at much sacrifice, because failure was not an option. Gracias! Furthermore, this dissertation could not have been completed without the help of numerous people. I would like to thank my advisor, Dr. Awatef Hamed, for having trusted in my capabilities and facilitated the opportunity for me to join the Vehicle Energy Systems and Integrations group at GE Aviation, which made this work possible.

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The use of vegetable oils as an energetic supply for transportation and heating purposes is becoming a possible and technically feasible option to reduce the energetic dependence on oil of developed countries. A mathematical model is developed in order to study the combustion of the most common rapeseed oil in heating devices. The study is about the simple model of droplet evaporation and burning, trying to highlight the most relevant physical processes occurring in the environment of the droplet during vaporization and subsequent combustion of rapeseed oil. A comparison with results obtained from the same model but applied to diesel fuel is provided, which allows to establish the most critical aspects affecting rapeseed oil use as a fuel in relation to that of conventional diesel.

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Abstract.International markets for wood biomass are currently emerging. Due to the corresponding environmental benefits, the domestic wood combustibles are an important energy resource, although certain measures must be taken to make the supply chain more cost-effective and efficient.One of the major contributors to the costs of wood products is transportation, which is determined by the geographical location of forests and energy crops. Within this paper techno-economic parameters of all substantial process steps along the biomass value chain are estimated. The potential for logs and chips, which includes justifiable transportation distances for these kinds of biomass, will be analyzed. To reach these objectives a simulation model has been developed. The results may be used for socioeconomical resource allocation and planning of future energy plants.