This thesis investigates the different strategies of operation and optimization criteria that a CCHP system can be operated under. As energy concerns increase, a major issue for the United States will be the efficiency of energy production. Due to this desire for the most efficient supply of energy CCHP will play an increasingly important role in both domestic and commercial applications as waste heat utilization provides an added measure of efficiency. The different strategies of operation under which a CCHP system can be operated under, electric load following and thermal load following, are defined in addition to the different optimization criteria that a CCHP system can be operated under. The different strategies and optimization criteria of CCHP operation are simulated for five various climate regions in the United States and the results for primary energy consumption, CO2 emissions, and cost of operation are compared.

This master's thesis deals with the integration of a mine gas burning cogeneration unit into industrial power system. The aim of the thesis is to design and evaluate different possibilities of integration the cogeneration unit into industrial power system. The first, theoretical part of the thesis discuss about cogeneration (combined heat and power). The technologies used for cogeneration are summed up as well as the possibilities of usage. The next part deals with the mine gas as the fuel for the cogeneration units. The lasts chapters of the theoretical part talks about terms for installation power source into industrial power system and about the possibilities of overflow of the electricity into distribution power system. The practical part deals with the installation of the 600 kW cogeneration unit into particular industrial power system. Four possibilities of operation mode of the cogeneration unit are design. At the end of the thesis the brief economical evaluation is accomplished.

This study examined the performance of a residential micro–cogeneration system based on a Stirling engine and fuelled by diesel and ethanol. An extensive number of engine tests were conducted to ensure highly accurate and reproducible measurement techniques. Appropriate energy efficiencies were determined by performing an energy balance for each fuel. Particulate emissions were measured with an isokinetic particulate sampler, while a flame ionization detector was used to monitor unburned hydrocarbon emissions. Carbon monoxide, nitric oxide, nitrogen dioxide, carbon dioxide, water, formaldehyde, acetaldehyde and methane emissions were measured using a Fourier transform infrared spectrometer. When powered by ethanol, the system had slightly higher thermal efficiency, slightly lower power efficiency and considerable reductions in emission levels during steady state operation. To further study engine behaviour, parametric studies on primary engine set points, including coolant temperature and exhaust temperature, were also conducted.

This study examined the performance of a residential micro–cogeneration system based on a Stirling engine and fuelled by diesel and ethanol. An extensive number of engine tests were conducted to ensure highly accurate and reproducible measurement techniques. Appropriate energy efficiencies were determined by performing an energy balance for each fuel. Particulate emissions were measured with an isokinetic particulate sampler, while a flame ionization detector was used to monitor unburned hydrocarbon emissions. Carbon monoxide, nitric oxide, nitrogen dioxide, carbon dioxide, water, formaldehyde, acetaldehyde and methane emissions were measured using a Fourier transform infrared spectrometer. When powered by ethanol, the system had slightly higher thermal efficiency, slightly lower power efficiency and considerable reductions in emission levels during steady state operation. To further study engine behaviour, parametric studies on primary engine set points, including coolant temperature and exhaust temperature, were also conducted.

Thesis (Ph. D.)--Dept. of Chemical Engineering, University of Sydney, 2004. / Includes bibliographical references. Also available in print form.

Made available in DSpace on 2014-06-11T19:30:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-19Bitstream added on 2014-06-13T20:39:47Z : No. of bitstreams: 1 ferreira_etf_me_guara.pdf: 940503 bytes, checksum: f4252f0750808c6fc7b5f6a45716b23c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O setor de celulose e papel é intensivo no uso de energia e apresenta uma alta participação no contexto industrial, especialmente baseado em fonte renovável gerada no processo de celulose. Embora a gaseificação de licor preto (BLG) ainda não seja dominada completamente, tem o potencial de se tornar uma alternativa importante para o setor de celulose e de papel: a queima de BLG em turbinas de gás deve garantir eficiências térmicas mais elevadas, um melhor uso dos recursos renováveis disponíveis, assim como permitir a recuperação química de insumos do processo, da mesma maneira que atualmente se faz com geradores de vapor de recuperação química Tomlinson. Neste trabalho será desenvolvida uma análise do setor de celulose e de papel que identifica a energia nele consumida e sua participação ambiental no contexto da matriz nacional. Baseado inicialmente no ciclo de Rankine, assumido como o estado atual de conhecimento dentro do setor, uma análise energética e exergética de um sistema de cogeração baseado em sistema de BLG associado com turbina a gás, gerador de vapor para recuperação de calor e turbina a vapor de contrapressão com extrações foi desenvolvida. O esquema proposto será desenvolvido para produzir energia elétrica/mecânica e dois níveis de vapor de pressão por garantir melhores condições operacionais comparativamente ao sistema tradicional. / The pulp and paper sector is intensive in the use of energy, and presents a high participation in industrial context, specially based in renewable source produced as byproduct in the pulp process. Although the black liquor gasification (BLG) is not a completely dominated technology, it has the potential of becoming an important alternative for the pulp and paper sector, once the burning of BLG in gas turbines should guarantee higher efficiencies, better use of the available renewable resources, also allowing the chemical recovery, just as is done nowadays with Tomlinson chemical recovery steam generations. In this dissertation, an analysis of the pulp and paper sector will be developed identifying its energy and environmental participation in the context of the national matrix. Based on the Rankine cycle, considered as the current state of knowledge, an energetic and exergetic analysis of a cogeneration system based on BLG system associated to gas turbine, heat recovery steam generator and backpressure steam turbine with extractions will be developed. The proposed scheme will be developed to produce electric/mechanical power and two pressure steam for guaranteeing better operational conditions comparatively to the traditional system.

The increase in energy costs, restructuring of electricity supply industry, quality of supply standards and environmental responsibility, initiated an investigation to utilize available carbon monoxide for cogeneration at an industrial site. A literature study indicated that most of the elements involved in establishing a cogeneration plant, were investigated individually, but had not been evaluated as a system with an indication of their relationships. The main objective of this study was to create a methodology to evaluate the impact of load scheduling, cogeneration and electrical tariff structures on the energy cost of an industrial operation. A modelling methodology was developed to evaluate the requirements for each of the elements, which were identified as the following processes: Plant and stockpiles Gas and fuel Power generation technology Electricity tariffs Financial evaluation Each of the processes' input requirements were evaluated in terms of being sufficient in providing either useful information or a model from which information could be manipulated. This methodology was then applied to a titanium slag producer with electric arc furnaces and excess carbon monoxide, which was burnt and treated as waste. / Dissertation (M Eng (Electrical Engineering))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted

This research explores whether Environmental Management Accounting can be applied to assist an Australian cogeneration company in improving both its financial performance as well as its environmental performance. Cogeneration or 'combined heat and power', in this particular case, involves the simultaneous production of heat and electricity using a single fuel, that is, natural gas. The heat generated is then used to produce steam to meet the customers' requirements as well as boost the production of electricity. Therefore, cogeneration provides greater efficiencies compared to traditional electricity generation methods because it utilizes heat that would otherwise be wasted. In addition, greenhouse gases emissions can be reduced substantially. The approach taken in this research is to assess whether an improvement in the energy efficiency of the cogeneration plant can lead to a reduction in greenhouse gases emissions. An improvement in energy efficiency means that either: • less gas is consumed, thus leading to cost savings; or • more electricity is generated for the same quantity of gas consumed, which leads to an increase in income and consequently profit. Therefore, an improvement in energy efficiency means an improvement in the financial performance. In addition, a reduction in the quantity of gas consumed or generating as much electricity as possible from a given quantity of gas can lead to a reduction in greenhouse gases emissions which means an improvement in the company's environmental performance. A case study method, which involves an Australian cogeneration company, is adopted because this would provide valuable in-depth practical insight into the operations and mechanisms of a company that is involved in combined heat and power generation. A review of the literature and the evidence collected indicated that a cogeneration plant's efficiency can be improved at least back to near the plant's designed efficiency. And, further improvements may be achieved by utilizing the latest technology although this involves capital investment. It is also established that an improvement in plant efficiency can reduce greenhouse gases emissions. This research then concludes that Environmental Management Accounting can help the case study company improve its financial and environmental performances. An Environmental Management Accounting system can provide the physical information that is not available in the existing management accounting system. Physical information such as the physical quantities of gas consumed, electricity and steam produced, and greenhouse gases emitted, can help the company in decision-making relating to improving plant efficiency as well as reducing greenhouse gases emissions.

<p><strong></strong>The aim of this Project is to study the influence of high return temperatures in district heating on the costs for heat and power production in a CHP plant.When the temperatures of the water coming back to the heating plant are so high, the overall performance of heat and power production is decreased and, consequently, also the production costs. Along the project, the influence of this temperature on the different parts of a CHP plant are analysed as well as the economical impact it has. At the same time, some general impacts on the entire network are mentioned.</p><p> </p><p>A real network is used in this project, and it is the net of district heating in Gävle (Sweden), and the most of the study is focus in its bigger combined heat and power production plant (CHP), called Johannes.</p>

Graduation date: 1995