Målet med denna undersökning är att teoretiskt undersöka den vatten/litiumbromidbaserade absorptionsprocessens potential ombord fartyg då processen enbart drivs av huvudmaskinens högtemperaturkylvatten. Undersökningen genomförs teoretiskt mot tre olika fartyg samt Sjöfartshögskolan i Kalmars maskinrumssimulator. För vardera fartyg undersöks driftenergikällan och kylbehovet ombord. Med det som underlag dras en slutsats om den vatten/ litiumbromidbaserade absorptionsprocessens potential ombord fartyget. Fartygens resultat ligger till grund för slutsatsen. Undersökningen visade att det finns potential för tekniken ombord undersökta fartyg.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2007. / Submitted by wesley oliveira leite (leite.wesley@yahoo.com.br) on 2009-10-02T19:28:32Z No. of bitstreams: 1 2007_EnioNascimentoCarvalho.pdf: 2105502 bytes, checksum: 65813f4b4858c9fa351308e192c9ae35 (MD5) / Approved for entry into archive by Guimaraes Jacqueline(jacqueline.guimaraes@bce.unb.br) on 2009-10-05T12:57:08Z (GMT) No. of bitstreams: 1 2007_EnioNascimentoCarvalho.pdf: 2105502 bytes, checksum: 65813f4b4858c9fa351308e192c9ae35 (MD5) / Made available in DSpace on 2009-10-05T12:57:08Z (GMT). No. of bitstreams: 1 2007_EnioNascimentoCarvalho.pdf: 2105502 bytes, checksum: 65813f4b4858c9fa351308e192c9ae35 (MD5) Previous issue date: 2007-11 / A finalidade deste trabalho é a modelagem física e simulação numérica de unidades resfriadoras de Líquidos por absorção a H2O-LiBr, nas configurações a simples e duplo efeito, com análise do efeito da utilização de aditivos na solução de H2O-LiBr e da influência do clima local sobre o desempenho e consumo energético da unidade. O modelamento físico de cada um dos componentes do sistema foi adotado baseando-se nos princípios clássicos da conservação de energia, junto com as correlações aplicáveis da transferência de calor e massa e equações que descrevem as propriedades dos fluidos de trabalho. O modelo adota um conceito semi-empírico, ou seja, parâmetros característicos para cada componente do sistema são utilizados. A aplicação do modelamento e simulação é realizada para quatro estudos de caso. No primeiro estudo de caso é simulada a operação de uma unidade resfriadora de líquido, de simples efeito, para as 8760 horas do ano, com aplicação em um edifício comercial. A simulação de uma unidade por absorção de duplo efeito, com estimativa do consumo de gás natural, durante o período de um ano de operação da máquina, é o objeto do estudo de caso dois. No terceiro estudo de caso, o consumo anual de combustível e desempenho de uma unidade de resfriamento de duplo efeito é comparado, para duas localidades climáticas diferentes. Finalmente, a avaliação da influência do uso de aditivos à solução H2O-LiBr, sobre o desempenho da unidade resfriadora é analisado no quarto estudo de caso, onde, se obteve um ganho no coeficiente de performance de até 5,5%, se comparado ao desempenho com uso da solução convencional de H2O-LiBr. Dessa forma, os resultados obtidos nesse trabalho permitem uma avaliação sobre a influência de vários fatores, no desempenho de unidades resfriadoras de líquidos por absorção e por conseqüência em seu consumo energético. _____________________________________________________________ ABSTRACT / The purpose of this work is the physical modeling and simulation of H2O-LiBr absorption chillers, in the single and double effect settings, with analysis of the effect of the use of additives in the solution of H2O-LiBr, and the influence of local climate on the performance and energy consumption of the unit. The physical modeling of each component of the system was adopted based on the classical principles of the energy conservation, along with the correlations for the heat and mass transfer or equations that describe the properties of the fluids of work. The model adopts a semi-empirical approach, where characteristic parameters for each component of the system are used. The application of physical modeling and simulation is carried out for four case studies. In the first case study is simulated the operation of a single effect chiller unit, for 8760 hours of the year, with implementation in a commercial building. The simulation of a double effect absorption machine with estimated consumption of natural gas during the period of one year of operation of the machine is the subject of the second case study. In case study three, the annual consumption of fuel and performance of a double effect absorption machine is compared for two different climatic areas. Finally, the evaluation of the influence of the use of additives to the solution H2O-LiBr, on the performance of the absorption chiller is analyzed in the fourth case study, where, was obtained an improvement in the COP of the system up to 5.5%, when compared with the COP of the conventional solution of H2O-LiBr. Thus, the results obtained in this work provide an assessment on the influence of various factors in the absorption chiller performance and result in their energy consumption.

Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2017-07-12T18:01:48Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Aida Avendano_Dissertacao_Eng Mecanica_UFPE.pdf: 2879829 bytes, checksum: 90b10e461eb8407986cea09be582a591 (MD5) / Made available in DSpace on 2017-07-12T18:01:48Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Aida Avendano_Dissertacao_Eng Mecanica_UFPE.pdf: 2879829 bytes, checksum: 90b10e461eb8407986cea09be582a591 (MD5) Previous issue date: 2016-01-29 / PRH-PB203 EQUIPAMENTOS/PETROBRAS / O processo de transferência de calor e massa dentro de um absorvedor tubular em espiral de Brometo de Lítio-Água (LiBr/H2O), resfriado com água em contracorrente, foi simulado usando um modelo matemático não linear. Para a simulação criou-se um programa em Matlab, usando o método numérico iterativo. Na calibração da malha física foram utilizadas condições de trabalho do absorvedor e o coeficiente de transferência de massa efetivo, Kef, obtidos da literatura. O coeficiente de transferência de calor global, U, foi calculado usando a resistência térmica global dentro do absorvedor. Para o cálculo do coeficiente de transferência de massa e de calor da interface solução-vapor se utilizaram correlações de analogia de transferência de calor e massa. As distribuições da temperatura e concentração da solução de LiBr/H2O, e a temperatura da água de resfriamento ao longo do comprimento do absorvedor foram determinadas utilizando o programa desenvolvido e os resultados obtidos apresentaram uma boa concordância quando comparados com dados reportados na literatura. Finalmente, foi analisada a influência da variação de alguns dos parâmetros, tais como temperatura e vazão de entrada da água de resfriamento, comprimento do absorvedor e material do tubo absorvedor dentro do absorvedor utilizando o programa desenvolvido. Os resultados obtidos mostraram que o programa desenvolvido permite predizer o comportamento do processo de transferência de massa e calor dentro do absorvedor em espiral de LiBr/H2O, além de representar uma ferramenta para o dimensionamento e/ou otimização deste componente. / The mass and heat transfer process in a spiral tubular absorber of the Water/Lithium Bromide (LiBr/H2O), cooled with in counter-current, was simulated using a nonlinear mathematical model. For the simulation was developed a program in Matlab, using the iterative numerical method. For the calibration of physical mesh were used absorber working condition and effective mass transfer coefficient, Kef, obtained from the literature. The global heat transfer coefficient, U, was calculated using the global thermal resistance within the absorber. For the calculation of the mass and heat transfer coefficient of the interface vapor-solution are used analogy correlations of mass and heat transfer. The temperature distribution and concentration of LiBr/H2O, and the cooling water temperature along of the length of the absorber were determined using the program developed, and the result obtained showed good agreement when compared to the data reported in the literature. Finally, the influence of the variation the some parameters were analyzed, such as inlet temperature and mass flow of cooling water, length of the absorber and material absorber tube within the absorber using the developed program. The result obtained showed that this program allowed to predict the behavior of the mass and heat transfer process in the absorber spiral of the LiBr/H2O, also represents a tool for the design and/or optimization of this component.

Les machines à absorption LiBr/H2O, appliquées aux systèmes de rafraîchissement par compression chimique présentent des avantages et des inconvénients à l'heure de leur intégration dans des bâtiments de basse consommation. Grandes tailles et coûts de mise en œuvre élevés les rendent peu attractives. Le développement de modules évapo-absorbeur et desorb-condenseur compacts et multifonctionnels, utilisant des échangeurs à film ruisselants couplés peuvent être une solution pour réduire les coûts de mise en œuvre, et augmenter la compacité et le rendement global du processus d'absorption. L'étude se centre autour de l'absorption de la vapeur d'eau à basse pression au sein d'un film de bromure de lithium qui ruisselle sur des échangeurs à plaques verticales. Les objectifs de la thèse sont le développement d'un modèle théorique simple décrivant le transfert de chaleur et de masse et sa validation à l'aide d'expériences de référence. Le modèle analytique est construit à l'aide des méthodes intégrales mettant en ouvre un écoulement laminaire établit à l'entrée de l'absorbeur et des conditions de saturation à l'interface Nous avons résolu le problème couplé de transfert de masse et de chaleur en prenant en compte couches limites thermiques et diffusives. Une représentation adimensionnelle des transferts à l'aide des nombres de Nusselt et de Sherwood en fonction du nombre de Graetz permet de décrire de manière générale les différentes zones thermiques et diffusives. Les variations de la température et la concentration à l'interface sont prises en compte, en considérant la linéarité des équations de transfert et, en appliquant la théorie des perturbations. Un banc d'essais a été spécifiquement développé pour l'étude de l'absorption de vapeur sur des films ruisselants de bromure de lithium à basse Reynolds (Re < 500). Il permet de fixer l'état de la solution LiBr à l'entrée (température, concentration et débit) ainsi que les conditions aux limites (pression de vapeur, condition adiabatique ou de température imposée à la paroi verticale). Différentes géométries de plaque sont comparées aux résultats du model en vu de quantifier l'impact des effets de bord et des instabilités. / Low pressure absorption machines, used in chemical compression refrigeration systems present several advantages and drawbacks in sustainable buildings integration. Large sizes and high implementation cost makes them unprofitable. Compact absorption machines with multifunctional absorption and desorption units using coupled falling film exchangers can be one solution to reduce implementation costs, increasing compactness and global machine performance. The present study is focused in the absorption process applied to vertical falling film exchangers and its improvement. The thesis objectives are: construction of a simple theoretical model; describing heat and mass transfer over a Lithium bromide falling film and model validation after data processing from a test bench build for this purpose. The analytic model is based on integral methods taking into account established flow conditions at the top of the plate, parabolic velocity profiles and saturation conditions at the interface. We solved the coupled heat and mass transfer problem considering thermal and diffusive boundary layers. Non dimensional representation of Nusselt (Sherwood) number as a function of the modified Graetz number, enables a general description of different transfer zones. Concentration and temperature evolution at the interface are studied considering the linearity of heat and mass transfer equations and applying perturbations theory. The test bench was created to study vapor absorption in a lithium bromide falling film at low Reynolds Numbers (Re < 500). Absorber inlet parameters (temperature, concentration and mass flow rate) and also boundary conditions (vapor pressure, adiabatic or isothermal condition at the vertical wall) can be varied. Different plate geometries were studied and compared with model results, to evaluate boundary conditions and instabilities. This study presents a simplified model for adiabatic and isothermal falling films absorbers with a local description of the absorption process. Influences of flow conditions and initial operation parameters were simulated, studied and compared with equivalent models and experimental data from literature;

No atual período de incertezas na geração e transmissão de energia elétrica no Brasil, a utilização dos sistemas de cogeração com uso de gás natural, tornou-se uma grande oportunidade econômica, estratégica e tecnológica, para as pequenas e médias empresas, considerando a extensão e perspectivas de expansão da rede de distribuição de gás natural. Uma empresa farmacêutica para se manter competitiva e reduzir o impacto dos custos indiretos em seus produtos, necessitava aumentar sua linha de injetáveis, produzindo no Brasil alguns medicamentos que até então eram importados de filiais em outros países e para que isto fosse possível, teria de investir na construção de novos laboratórios, compra de equipamentos, aumento de utilidades para sua fabricação como vapor de água para injetáveis, sistema de HVAC para salas limpas, o que levaria a um aumento de consumo de energia, vapor, água de refrigeração. Este investimento inviabilizaria a produção desta nova linha de produtos, pois tanto o custo do investimento em novas centrais de utilidades, quanto mais o custo desta geração e sua manutenção, decretariam um fim para a esta empreita. Neste trabalho, apresentou-se uma alternativa como solução para viabilizar esta instalação, trocando-se os chillers convencionais por um chiller de absorção, que alem de consumir pouca energia elétrica utilizando a troca térmica entre brometo de lítio e vapor para gerar água de resfriamento para o sistema de ar condicionado, o sistema proposto proporcionou um aumento de fornecimento de vapor não só para alimentar o sistema de HVAC como para a produção da fabrica, anexo a esta caldeira de recuperação é proposto a instalação de uma turbina á gás com condições suficientes de gerar energia elétrica para todo o site e ainda ter condições de negociar o excedente de energia para ser vendido para a concessionária. O resultado deste sistema proposto demonstrou uma excelente eficiência, frente ao sistema convencional, o que tecnicamente se apresentou como muito viável. / In the current period of uncertainty in the generation and transmission of electric energy in Brazil, the use of cogeneration systems using natural gas, has become a great economic opportunity, strategic and technology for small and medium enterprises, considering the extent and prospects for expansion of the distribution of natural gas. A pharmaceutical company to remain competitive and reduce the impact of indirect costs in their products, needed to increase its line of injectables, producing here in Brazil some drugs that were previously imported from subsidiaries in other countries and to make this possible, would invest in building new laboratories, purchase equipment, increase of utilities for its manufacture steam as water for injection, the HVAC system for clean rooms, leading to an increased consumption of energy, steam, cooling water. This investment would make impracticable the production of this new line of products, therefore not only the cost of the investment in new central offices of utilities, the more the cost of this generation of utilities and its maintenance, would decree an end for the this take over on a contract basis. In this work, presented as an alternative solution to enable this facility, exchanging conventional chillers for an absorption chiller, which besides consume little electricity using the heat exchange between lithium bromide to generate steam and cooling water for the air conditioning system, the proposed system provided an increased supply of steam to feed not only the HVAC system for the production of manufactures, attached to this recovery boiler is proposed to install a gas turbine with sufficient conditions generate electricity for the entire site and still be able to trade the surplus energy to be sold to the utility. The result of this proposed system showed an excellent efficiency, compared to the conventional system, which technically is presented as very viable.

Accurate modeling of mixed solvent electrolyte systems is difficult and is not readily available in property modeling software such as Aspen Plus. Support for modeling these systems requires the knowledge and input of parameters specific to the compounds in question. The need for these parameters is particularly relevant in simulating new designs based upon recent developments in a concept known as pass-through distillation (PTD). In support of a specific application of PTD, this work determines and validates with existing experimental data, accurate user-parameters for the eNRTL property model in the ternary system of ethanol, water, and lithium bromide. Furthermore, this work creates the foundation for simulating this new PTD process by modeling the removal of bioethanol from a fermentation broth using low temperature evaporation in conjunction with absorption and stripping units to omit the need of a condenser requiring refrigeration. This will enable future investigations into the applications of PTD as well as provide a foundation for modeling the ternary system of ethanol, water and lithium bromide.

Content: Nowadays, tannery pollution is of great concern worldwide. The unhairing and fiber bundle-opening processes contribute the majority of the pollution by the use of sodium sulfide and calcium hydroxide, which were proposed to be replaced by neutral protease combined with (potassium chloride) KCl, (lithium bromide)LiBr/1-allyl-3-methylimidazolium chloride([AMIm]Cl) in the present work. Proper amount of KCl can speed up the unhairing with the grain not destroyed by the neutral protease. Four methods for unhairing and fiber bundle-opening were used as follows: 1. Two steps in different floats as KCl/neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 2. Two steps in different floats as neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 3. One step in the same float as neutral protease for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. 4. One step in the same float as neutral protease/KCl for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. It was found that using neutral protease/KCl solution for unhairing and LiBr/[AMIm]Cl solution for fiber bundle-opening is the best in fiber bundle-opening at the liming process. Besides, all the methods used here are better than the traditional liming processes (C) from viewpoints of unhairing and fiber bundleopening. Take-Away: 1. The addition of potassium chloride can improve the stability of neutral protease solution. 2. The catalytic efficiency of the enzyme was improved because of adding potassium chloride can enhance the contact rate of neutral protease with substrate. 3. Ionic liquids have less hydrolysis of collagen and larger dissolution of polysaccharides.

This diploma work aims to evaluate the functional connection of the cogeneration unit with an internal combustion engine and an absorption heat pump to increase the heating effect of the cogeneration. The aim of this work is to design a functional system and evaluate it from the technical - economic terms. In the introduction of the theoretical work the applied cogeneration technologies used in combined heat and power production are presented. Then there is described the principle of heat pumps, their basic components and theoretical comparison of compression and absorption heat pumps. In the practical part of this work is for a specific application in the area Technická 2 proposed merger of the cogeneration unit with an internal combustion engine and an absorption heat pump, while detailed design parameters used in absorption heat circulation are set. At the end of this paper there are designed various heat exchangers of applied absorption heat pump. The final part of the work is devoted to technical - economic assessment of applied design. In this assestment three different types of heat pumps are compared: Absorption heat pump with working solution H2O-LiBR, absorption heat pump with working fluids NH3-H2O and compressor heat pump.

Les machines à absorption LiBr/H2O, appliquées aux systèmes de rafraîchissement par compression chimique présentent des avantages et des inconvénients à l'heure de leur intégration dans des bâtiments de basse consommation. Grandes tailles et coûts de mise en œuvre élevés les rendent peu attractives. Le développement de modules évapo-absorbeur et desorb-condenseur compacts et multifonctionnels, utilisant des échangeurs à film ruisselants couplés peuvent être une solution pour réduire les coûts de mise en œuvre, et augmenter la compacité et le rendement global du processus d'absorption. L'étude se centre autour de l'absorption de la vapeur d'eau à basse pression au sein d'un film de bromure de lithium qui ruisselle sur des échangeurs à plaques verticales. Les objectifs de la thèse sont le développement d'un modèle théorique simple décrivant le transfert de chaleur et de masse et sa validation à l'aide d'expériences de référence. Le modèle analytique est construit à l'aide des méthodes intégrales mettant en ouvre un écoulement laminaire établit à l'entrée de l'absorbeur et des conditions de saturation à l'interface Nous avons résolu le problème couplé de transfert de masse et de chaleur en prenant en compte couches limites thermiques et diffusives. Une représentation adimensionnelle des transferts à l'aide des nombres de Nusselt et de Sherwood en fonction du nombre de Graetz permet de décrire de manière générale les différentes zones thermiques et diffusives. Les variations de la température et la concentration à l'interface sont prises en compte, en considérant la linéarité des équations de transfert et, en appliquant la théorie des perturbations. Un banc d'essais a été spécifiquement développé pour l'étude de l'absorption de vapeur sur des films ruisselants de bromure de lithium à basse Reynolds (Re < 500). Il permet de fixer l'état de la solution LiBr à l'entrée (température, concentration et débit) ainsi que les conditions aux limites (pression de vapeur, condition adiabatique ou de température imposée à la paroi verticale). Différentes géométries de plaque sont comparées aux résultats du model en vu de quantifier l'impact des effets de bord et des instabilités.

Goal of this thesis is to introduce technology of absorption heat pumps in various modifications. Technical design draft is created for chosen modification (single stage unit water-LiBr) and based on given parameters calculated in computing software EES (engineering equation solver) and process is explained step-by-step. Following part of thesis contains reference design draft of heat plant and this design is used to demonstrate several different options of applying absorption heat pump including version capable of providing also cooling. Those options are compared with each other from technological and economical stand point.