The objective of this thesis is to maintain the stable operation of an industrial cogeneration system after transient disturbance caused by external utility system. Both dynamic stability and the transient stability of the power system are investigated. The dynamic stability analysis is to derive the stable frequency of the power system without causing the system frequency oscillation with the small amount of load change. On the other hand, the transient stability analysis will simulate the system response during system fault contingency to determine the system capability to restore the stable operation. Based on the transient stability analysis, the protection relay setting for both tie line tripping and load shedding are derived. In order to confer the influence of the system stability with the industrial cogeneration system, we use the practical cogeneration system of China Steel Corporation (CSC) to analyze the transient stability of the whole system and dynamic stability of 700B/800B subsystem. Executing the load flow analysis of the CSC cogeneration system is solved by CYMSTAB software to derive the system prefault operating data. The system transient parameters are used to construct the system model. The system transient stability analysis is executed to solve the strategies of tie line tripping and the amount of load shedding to restore the system stability after fault contingency. Finally, the external fault at Fong-Nong substation in Tai-power is used to simulate and analyze the transient stability of CSC cogeneration system. Besides, the dynamic model of 700B/800B subsystem of the CSC cogeneration and selected adaptive control parameters are applied to simulate the dynamic response of system islanding operation.

A micro-cogeneration system based on an ArtesJet KJ-66 hobby microturbine may be able to provide a single family dwelling with required heat and power, increasing total efficiency due to utilization of waste heat. The feasibility of such a system was investigated. An engine model based on the similar JG-100 engine was developed, written in Microsoft Excel™ and Visual Basic™. The predicted running characteristics of the KJ-66 were simulated, and a prediction of how these characteristics would be shifted if a diffuser was attached to the engine was made. An experimental test program was carried out on the KJ-66 engine to determine if this prediction was correct, and to more accurately characterize the performance of the engine. Two diffusers were constructed to use with the testing, along with the nozzle that was supplied with the engine. Having the diffusers on the engine reduced the fuel air ratio by approximately 20% as predicted. A hypothetical micro-cogeneration system was simulated building on the earlier engine model, with modified turbomachinery maps and combustor performance based on the experimental data. An 85% effective recuperator was included in the model, as well as a recovery heat exchanger. The simulation showed an electrical output of 8.9 kW, a heat output of 30.9 kW, an electrical efficiency of 15.5%, and a total efficiency of 69.0%. While these efficiencies are low, improvements could be made by modifying the turbomachinery and by using a condensing recovery heat exchanger to give a better overall efficiency for the micro-cogeneration system. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-09-26 22:03:57.11

No description available.

M.Ing. / Currently, electrical resistance heaters are used to produce most of the hot water in South Africa. Increasing electricity tariffs make these devices very expensive. This study investigates the economic savings potential of using a cogeneration system made of microturbines, heat pumps and heat exchangers. Specifically the heating of water for large residential units is investigated. Different economic parameters are used to compare microturbine heat pump systems with electrical resistance heaters, natural gas boilers and heat pumps. For 27 main centres in South Africa, the amount of hot water is determined where a cogeneration system is economically more viable than other types of water heaters. It has been concluded that the most important influence factor is the electricity tariff. The higher the electricity tariff in a city, the smaller the number of domestic consumers where a cogeneration system becomes viable.

Throughout the process industry, the conservation and allocation of mass and energy resources plays a pivotal role in the site wide optimization of a plant. Typically, raw materials are transformed into products, byproducts and wastes through pathways involving heating/cooling, pressure changes, mixing, reactions and separations. These pathways often require the addition or removal of energy from the system. The optimal management of such a system therefore requires conserving resources through the appropriate allocation of materials and energy. In a typical plant, there are both mass and energy objectives that require optimization. This dissertation will focus on optimizing the mass and energy resources present in a utility system. This will entail developing a novel framework of techniques to: target and design steam cogeneration networks while minimizing fuel requirements, identifying and utilizing sources of waste heat and incorporating heat pipes to enhance heat exchange networks. Additionally, a specific case of waste recovery will be examined when properties are the primary concern.

Throughout the process industry, the conservation and allocation of mass and energy resources plays a pivotal role in the site wide optimization of a plant. Typically, raw materials are transformed into products, byproducts and wastes through pathways involving heating/cooling, pressure changes, mixing, reactions and separations. These pathways often require the addition or removal of energy from the system. The optimal management of such a system therefore requires conserving resources through the appropriate allocation of materials and energy. In a typical plant, there are both mass and energy objectives that require optimization. This dissertation will focus on optimizing the mass and energy resources present in a utility system. This will entail developing a novel framework of techniques to: target and design steam cogeneration networks while minimizing fuel requirements, identifying and utilizing sources of waste heat and incorporating heat pipes to enhance heat exchange networks. Additionally, a specific case of waste recovery will be examined when properties are the primary concern.

A Thermal loss occurs when energy is consumed and work is done by a system. The use of ElectricalAppliances in households consumes energy and causes Thermal loss which gets dissipated to itssurrounding surfaces. Harnessing these losses by using principles like Cogeneration or CombinedHeat and Power (CHP) would result in the development of new energy techniques and provide asecure and decentralized supply of Energy to the Built Environment. This study aimed at assessing theaverage Thermal losses occurring from the use of Electrical appliances in Indian households. For thepurposes of this study, a middle-class neighborhood in the capital city of Hyderabad, in the southernstate of Andhra Pradesh, India was chosen where there is an increased demand and usage ofElectricity. The method for this study was centered on a systems based approach and made use of theFourier’s Law of Conduction. As a primary step towards this study, a survey was conducted among100 dwellings with the objective of determining the, average number of people living in thehousehold, their age, total area of the household, common materials used in construction, type ofappliances which consume electricity and the average monthly consumption of electricity. As asecondary step, the data obtained from the survey was used to construct a computer based simulationmodel using PowerSim and the Fourier’s Law of Heat conduction. This computer model emulated thesystems based approach by considering the surrounding Wall & Ceiling surfaces, Floors, Window &Door surfaces as detached systems. The study revealed that of the 175kW of electricity consumed per month, 32% was dissipated tosurrounding surfaces as Thermal energy which could be harnessed for other forms of RenewableEnergy like Electricity. This would contribute to India’s efforts towards Sustainable Development andmake the households of the country a part of an energy-inclusive society by mitigating CO2 emissions.

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The intent of this study was to investigate the efficient use of energy by developing an energy efficient grocery store combined with cogeneration. This study demonstrated the potential to reduce the energy use in buildings, by implementing a decentralized source of energy generation that allowed for the use of a portion of the energy generated to be shared across building boundaries. This study considered a high energy use building such as a grocery store to be a part of a residential community, which could potentially participate in the sharing of energy across building boundaries. To better utilize energy resources the study proposed the implementation of a cogeneration facility to supply energy primarily to the store. Surplus energy generated by this cogeneration system was then shared with the requirements of the surrounding residential community. Finally, in order to better account for energy consumption of these buildings both site and source energy was considered. The study focused on hot and humid climates. This study was presented in two parts: Analyzing conventional grocery store systems to determine the maximum savings possible; and examining the option of co-generation systems to provide power to grocery stores and a portion of the community in order to reduce source energy use for the grocery store and a portion of the surrounding community. Source energy savings were in the range of 47% to 54% depending on the energy efficiency measures selected and the cogeneration configuration determined in the grocery store. Economic payback periods in the range of 4 to 7 years (time until zero net present value) were observed. The selection of appropriate options was narrowed down to two options that utilized more thermal energy within the boundaries of the store and generated more amount of surplus energy to be absorbed by the neighboring residential buildings.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 345-352).