Browsing by Author "Doulgeris, Georgios"
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Item Open Access Techno-economic analysis of compressed air energy storage systems(Cranfield University, 2010-11) Bozzolani, Emanuele; Singh, R.; Doulgeris, GeorgiosThe continuous escalation of intermittent energy added to the grid and forecasts of peaking power demand increments are rising the effort spent for evaluating the economic feasibility of energy storages. The aim of this research is the techno-economic analysis of Compressed Air Energy Storage (CAES) systems, capable of storing large quantities of off-peak electric energy in the form of high-pressure air, as an ―energy stock‖ which allows the production of high-profit on-peak electricity when required by the grid. Several studies of both conventional and innovative adiabatic concepts are carried out in order to identify and improve the parameters that mostly affect the plant performances. Technical models, that consider the effect of time, are developed to evaluate the parameters that reduce the electric energy spent for compressing the air and that maximize the electric energy produced. In the conventional plant, particular attention is put on the understanding of the effects of air storage pressure range, recuperator, reheating and Turbine Inlet Temperature. For the adiabatic instead, a thorough analysis of the challenging Thermal Energy Storage (TES) is performed for understanding the advantages and drawbacks of this novel efficient concept of CAES. In a further step the economic analyses are aimed at evaluating the different configurations proposed in the technical investigation and the effects that variations of generation train and storage characteristics have on the profitability. After an analysis of the TES impact on the profits, a final comparison is carried out against two existing technologies: Pumped Hydro Energy Storage and gas turbine. The results of these studies confirm, from a technical and economic point of view, the reasons of the growing interest toward CAES as a feasible solution to manage the intermittent energy production. In particular they underline the conventional CAES as promising technology to undertake.Item Open Access Techno-environmental assessment of marine gas turbines for the propulsion of merchant ships(Cranfield University, 2011-07) Bonet, Mathias Usman; Pilidis, Pericles; Doulgeris, GeorgiosThis research study seeks to evaluate the techno-economic and environmental implications of a variety of aero-derivative marine gas turbine cycles that have been modelled for the propulsion of different types of merchant ships. It involves the installation and operation of gas turbine propulsion systems in different marine environmental conditions and aims to evaluate the effect of the aerodynamic and hydrodynamic variations expected to be encountered by these ships when they navigate across different climates and oceans along selected fixed trade routes. A combination of simulation tools developed in Cranfield University at the Department of Power and Propulsion including the validated gas turbine modelling and simulation code called “Turbomatch” and the “APPEM” simulation code for the analysis and Prediction of exhaust pollutants have been used along with the ongoing development of an integrated marine gas turbine propulsion system simulation platform known as “Poseidon”. It is the main objective of this research to upgrade the competence level of “Poseidon” so as to facilitate the conduct of a variety of longer and more complex oceangoing voyage scenarios through the introduction of an ambient temperature variation numerical module. Expanding the existing code has facilitated the prediction of the effect of varying aerodynamic and hydrodynamic conditions that may be encountered by gas turbine propulsion systems when such ships navigate through unstable ocean environments along their fixed trade routes at sea. The consequences of operating the marine gas turbines under ideal weather conditions has been investigated and compared with a wide range of severe operating scenarios under unstable weather and sea conditions in combination with hull fouling has been assessed. The techno-economic and environmental benefits of intercooling/exhaust waste heat recuperation of the ICR model have been predicted through the evaluation of different ship propulsion performance parameters in a variety of voyage analysis leading to the prediction of fuel consumption quantities, emission of NOx, CO2, CO and UHCs and the estimation of the HPT blade life as well. The different gas turbine cycle configurations of the research were found to respond differently when operated under various environmental profiles of the ship’s trade route and the number of units for each model required to meet the power plant capacity in each scenario and for each ship was assessed. The study therefore adds to the understanding of the operating costs and asset management of marine gas turbine propulsion systems of any ocean carrier and in addition it reveals the economic potentials of using BOG as the main fuel for firing gas turbine propulsion plants of LNG Carriers.Item Open Access Turboelectric Distributed Propulsion System Modelling(Cranfield University, 2013-12) Liu, Chengyuan; Singh, R.; Laskaridis, Panagiotis; Doulgeris, GeorgiosThe Blended-Wing-Body is a conceptual aircraft design with rear-mounted, over wing engines. Turboelectric distributed propulsion system with boundary layer ingestion has been considered for this aircraft. It uses electricity to transmit power from the core turbine to the fans, therefore dramatically increases bypass ratio to reduce fuel consumption and noise. This dissertation presents methods on designing the TeDP system, evaluating effects of boundary layer ingestion, modelling engine performances, and estimating weights of the electric components. The method is first applied to model a turboshaft-driven TeDP system, which produces thrust only by the propulsors array. Results show that by distributing an array of propulsors that ingest a relatively large mass flow directly produces an 8% fuel burn saving relative to the commercial N+2 aircraft (such as the SAX-40 airplane). Ingesting boundary layer achieves a 7-8% fuel saving with a well-designed intake duct and the improved inlet flow control technologies. However, the value is sensitive to the duct losses and fan inlet distortion. Poor inlet performance can offset or even overwhelm this potential advantage. The total weight of the electric system would be around 5,000-7,000 kg. The large mass penalties further diminish benefits of the superconducting distributed propulsion system. The method is then applied to model a turbofan-driven TeDP system, which produces thrust by both the propulsors array and the core-engines. Results show that splitting the thrust between propulsors and core-engines could have a beneficial effect in fuel savings, when installation effects are neglected. The optimised thrust splitting ratio is between 60-90%, the final value depends on the propulsor intake pressure losses and the TeDP system bypass ratio. Moreover, splitting the thrust can reduce the weight of the electric system with the penalty of the increased core-engine weight. In short, if the power density of the superconducting system were high enough, turboshaft-driven TeDP would be preferable to power the N3-X aircraftItem Open Access Voyage analysis of a marine gas turbine engine installed to power and propel an ocean-going cruise ship(World Academy of Science, Engineering and Technology, 2019-02-02) Bonet, Mathias; Pilidis, Pericles; Doulgeris, GeorgiosA gas turbine-powered cruise Liner is scheduled to transport pilgrim passengers from Lagos-Nigeria to the Islamic port city of Jeddah in Saudi Arabia. Since the gas turbine is an airbreathing machine, changes in the density and/or mass flow at the compressor inlet due to an encounter with variations in weather conditions induce negative effects on the performance of the power plant during the voyage. In practice, all deviations from the reference atmospheric conditions of 15 oC and 1.103 bar tend to affect the power output and other thermodynamic parameters of the gas turbine cycle. Therefore, this paper seeks to evaluate how a simple cycle marine gas turbine power plant would react under a variety of scenarios that may be encountered during a voyage as the ship sails across the Atlantic Ocean and the Mediterranean Sea before arriving at its designated port of discharge. It is also an assessment that focuses on the effect of varying aerodynamic and hydrodynamic conditions which deteriorate the efficient operation of the propulsion system due to an increase in resistance that results from some projected levels of the ship hull fouling. The investigated passenger ship is designed to run at a service speed of 22 knots and cover a distance of 5787 nautical miles. The performance evaluation consists of three separate voyages that cover a variety of weather conditions in winter, spring and summer seasons. Real-time daily temperatures and the sea states for the selected transit route were obtained and used to simulate the voyage under the aforementioned operating conditions. Changes in engine firing temperature, power output as well as the total fuel consumed per voyage including other performance variables were separately predicted under both calm and adverse weather conditions. The collated data were obtained online from the UK Meteorological Office as well as the UK Hydrographic Office websites, while adopting the Beaufort scale for determining the magnitude of sea waves resulting from rough weather situations. The simulation of the gas turbine performance and voyage analysis was effected through the use of an integrated Cranfield-University-developed computer code known as ‘Turbomatch’ and ‘Poseidon’. It is a project that is aimed at developing a method for predicting the off design behavior of the marine gas turbine when installed and operated as the main prime mover for both propulsion and powering of all other auxiliary services on board a passenger cruise liner. Furthermore, it is a techno-economic and environmental assessment that seeks to enable the forecast of the marine gas turbine part and full load performance as it relates to the fuel requirement for a complete voyage.