12,646 research outputs found

    Study of methane fuel for subsonic transport aircraft

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    The cost and performance were defined for commercial transport using liquid methane including its fuel system and the ground facility complex required for the processing and storage of methane. A cost and performance comparison was made with Jet A and hydrogen powered aircraft of the same payload and range capability. Extensive design work was done on cryogenic fuel tanks, insulation systems as well as the fuel system itself. Three candidate fuel tank locations were evaluated, i.e., fuselage tanks, wing tanks or external pylon tanks

    Exploitation of Liquefied Natural Gas Cold Energy in Floating Storage Regasification Units

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    [Abstract] This paper aims to review regasification technology installed in Floating Storage Regasification Units (FSRUs) and the potential offered by the exploitation of cold energy from liquefied natural gas (LNG) in these vessels. The assessment describes the main characteristics of regasification systems along with their respective advantages and limitations. Regasification systems in direct exchange (seawater and steam) and systems with intermediate fluids that use propane or water-glycol in the heat transfer process are studied. In recent years, water-glycol systems have cornered the market. The mixture, besides reducing the risk of freezing, is non-flammable, economical and highly available. Thermodynamic analysis of the regasification process shows that LNG cold energy is the main source of residual energy in these vessels; the specific energy and exergy content is more than double that of engine exhaust gases. Exploitation of this cold energy in power cycles could significantly reduce FSRUs harmful emissions and electrical energy could even be exported to shore. The organic Rankine cycle technology is the most well-known and widely studied, although scientific literature is scarce and there is a need to propose new regasification systems with cold energy exploitation that can be adopted on these vessels

    The development of cryogenic storage systems for space flight

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    Development of cryogenic storage systems for manned space fligh

    Technology evaluation of heating, ventilation, and air conditioning for MIUS application

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    Potential ways of providing heating, ventilation, and air conditioning for a building complex serviced by a modular integrated utility system (MIUS) are examined. Literature surveys were conducted to investigate both conventional and unusual systems to serve this purpose. The advantages and disadvantages of the systems most compatible with MIUS are discussed

    Methodology of Supervision by Analysis of Thermal Flux for Thermal Conduction of a Batch Chemical Reactor Equipped with a Monofluid Heating/Cooling System

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    We present the thermal behavior of a batch reactor to jacket equipped with a monofluid heating/cooling system. Heating and cooling are provided respectively by an electrical resistance and two plate heat exchangers. The control of the temperature of the reaction is based on the supervision system. This strategy of management of the thermal devices is based on the usage of the thermal flux as manipulated variable. The modulation of the monofluid temperature by acting on the heating power or on the opening degrees of an air-to-open valve that delivers the monofluid to heat exchanger. The study shows that the application of this method for the conduct of the pilot reactor gives good results in simulation and that taking into account the dynamics of the various apparatuses greatly improves ride quality of conduct. In addition thermal control of an exothermic reaction (mononitration) shows that the consideration of heat generated in the model representation improve the results by elimination any overshooting of the set-point temperature

    Review of the advances in solar-assisted air source heat pumps for the domestic sector

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    Solar assisted air source heat pump shows great potential as a promising energy-saving heating technology, which integrates solar collector and air source heat pump. It is widely considered for supplying hot water, space heating and/or space cooling in the domestic sector. The performance of solar assisted air source heat pumps can be evaluated in system level by parameters such as coefficient of performance, seasonal performance factor, energy consumption, solar fraction as well as initial and operating costs, and in component level by parameters such as efficiencies of solar collection and thermal energy storage. Their performances are affected by many factors such as system configuration, components size, working fluid, working conditions and weather conditions. This paper presents a comprehensive review on the recent advances in solar assisted air source heat pump for the domestic sector in terms of system configuration, solar collectors, thermal energy storage, defrosting method and the perspective areas of further investigations. The results of this review confirm that research is still required to improve the performance of such a combined system and reduce initial cost compared with existing heating systems based on hydrocarbon combustion. The information presented in this paper is beneficial to the researchers, small and medium-sized enterprises supplying renewable energy system technologies, heating engineers and service workers, energy policy and decision makers, environmental activists and communities

    The Design and Implementation of Bloqqi - A Feature-Based Diagram Programming Language

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    This dissertation presents the design and implementation of a new block diagram programming language, Bloqqi, for building control systems with focus on variability. The language has been developed in collaboration with industry with the goal of reducing engineering time and improving reuse of functionality.When building a control system for a plant, there are typically different variants of the same base functionality. A plant may have several variants of a tank, for example, one variant with heating and another one without. This dissertation presents novel language mechanisms for describing this kind of variability, based on diagram inheritance. For instance, Bloqqi supports specifying what features, like heating, the base functionality can have. These specifications are then used to automatically derive smart-editing support in the form of a feature-based wizard. In this wizard, the user can select what features the base functionality should have, and code is generated corresponding to these features. The new language mechanisms allow feature-based libraries to be created and extended in a modular way.This dissertation presents techniques for implementing rich graphical editors with smart editing support based on semantic analysis. A prototype compiler and graphical editor have been implemented for the language, using the semantic formalism reference attribute grammars (RAGs). RAGs allow tools to share the semantic specifications, which makes it possible to modularly extend the compiler with support for advanced semantic feedback to the user of the graphical editor

    Centrifugal pumps for rocket engines

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    The use of centrifugal pumps for rocket engines is described in terms of general requirements of operational and planned systems. Hydrodynamic and mechanical design considerations and techniques and test procedures are summarized. Some of the pump development experiences, in terms of both problems and solutions, are highlighted

    Implementation of conductivity sensors in the Murdoch University pilot plant

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    The strength of the Instrumentation and Control Major at Murdoch University relies heavily on the operation and capability of the Pilot Plant. This facility exposes students to real-world systems and provides an opportunity to apply theoretical knowledge to common industrial equipment. As such, it is continuously desired to increase the capabilities, and optimise the performance of the pilot plant to provide students and staff with a facility that can be used to deliver the best possible introduction to the process control industry. This project builds on knowledge acquired from the Industrial Computer Systems and Instrumentation and Control majors at Murdoch University and uses skills and knowledge developed from both disciplines to deliver a final operational product. Modbus TCP conductivity sensors were installed on each tank of the continuously stirred tank reactor (CSTR) system, and a previously unused tank was used to introduce an electrolyte solution to the system. This increases complexity by providing additional process variables that can be measured in each tank, and controlled by making using of the dye tank pump and recycle stream. This document is created with future students in mind, and as such it is recommended to use this document as a first point before considering conductivity experiments. Instrumentation and software used is introduced and followed by an explanation of the Modbus protocol and how this communicates with the Experion system. The report then explores the implementation of these sensors and the thorough testing that preceded to ensure successful operation. Many issues were found, and limitations of the system will be discussed. As well as this, the development of conductivity control strategies utilising the dye tank pump and recycle stream were created to analyse the performance of the new equipment, and its viability for use in future coursework
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