The increasing demand for the domestic refrigeration system urges the development of greener form of refrigeration. The eighty-year-old single pressure absorption refrigeration system invented by Albert Einstein and Leo Szilard is attractive as it has no mechanical moving parts and can be driven by heat alone. However, the literature on either the refrigeration system or its components is scarce. The bubble pump is the crucial component of the refrigeration system, but it is poorly understood as its mass flow rate cannot be readily predicted. Two new time correlations in the mass flow rate prediction are presented to increase the accuracy when heat losses occur in the bubble pump. These time correlations are verified with the experimental results. When either the heat input or submergence ratio increases, the accuracy of the prediction increases. The percentage of error for the high heat input or submergence ratio is within ±10%. Working conditions and system dimension have a direct influence to the bubble pump performance. For instance, the bubble pump experimental results show that the mass flow rate of the bubble pump increases when either the submergence ratio or the concentration of ammonia increases. However, the performance of the bubble pump drops when the tube diameter or the system pressure increases. The Einstein refrigeration system has only been rebuilt once since it invention. In order to redesign and rebuilt a practical Einstein refrigeration system, some challenges are revealed. With the combination of the good features of the designs of Einstein and Delano, a new prototype has been rebuilt and tested. The practical results obtained from the five experimental setups are the first set of experimental result that has ever been presented. The highest cooling capacity and coefficient of performance (COP) obtained are 5 W and 0.04 respectively.

The diffusion absorption refrigeration (DAR) cycle is a promising technology for fully thermally driven cooling. It is well suited to applications in medicine refrigeration and air-conditioning in off-grid settings. However, design and engineering knowhow for the technology is limited; therefore, system development has historically been an iterative and expensive process. Additionally, conventional system designs require high-grade energy input for operation, and are unsuitable for low-temperature solar- or waste-heat activated applications. In the present effort, component- and system-level DAR engineering analyses are performed. Detailed bubble-pump generator (BPG) component models are developed, and are validated experimentally and with direct simulations. Investigations into the BPG focus on the Taylor flow pattern in the intermediate Bond number regime, which has not yet been thoroughly characterized in the literature, and has numerous industry applications, including nuclear fuel processing and well dewatering. A coupling-fluid heated BPG design is also investigated experimentally for low-source-temperature operation. Phase-change simulation methodologies are developed to rigorously study the continuously developing flow pattern in this BPG configuration. Detailed component-level models are also formulated for all of the other DAR heat and mass exchangers, and are integrated to yield a complete system-level model. Results from these modeling studies are applied to develop a novel fully passive low-source-temperature (110 - 130°C) DAR system that delivers refrigeration grade cooling. This design achieves operation at target conditions through the use of alternate working fluids (NH3-NaSCN-He), the coupling-fluid heated BPG, and a novel absorber configuration. The complete DAR system is demonstrated experimentally, and evaluated over a range of operating conditions. Experimental results are applied to assess and refine component- and system- level models.

Efficient heat management in energy intensive applications such as server and data centers has become a national concern due to the magnitude of the energy consumed. In that matter, the absorption refrigeration system is an attractive solution because the abundant waste heat available in the data centers can be recycled to run the heat pump, which will bring about significant cooling cost savings. The use of absorption refrigeration has been limited due to the drawbacks related to the working fluids in commercially available equipment. Recently, ionic liquids (ILs) have been suggested as the absorbent in absorption heat pumps due to their tunable properties, negligible volatility and high thermal stability. The non-random-two-liquid-model was initially used to analyze the feasibility of the new IL based working fluid. Hydrofluorocarbons (HFCs) were paired with IL absorbents due to their good properties as refrigerants. The cooling-to-total-energy (CE) efficiency had a local maximum with respect to desorber temperature due to the solubility limit at lower temperatures and large heating requirements at higher temperatures. The waste heat recycling coefficient of performance (COP) continually increased with respect to desorber temperature and among the HFCs studied in this work, R134 gave the highest COP value, which is up to 40 times higher than that of typical vapor compression systems and 60 times higher than NH3/H2O and H2O/LiBr absorption refrigeration systems. A Redlich-Kwong equation of state (RK-EOS) was employed for accurate computation of mixture properties over a wide range of operating conditions. Analysis using the RK-EOS model showed that the CE trend in refrigerants followed the trend of solubility in the [bmim][PF6] IL. However, the trend in COP was different from that of CE as the operating pressure ranges became an important factor. Required pumping work of the working fluids has also been analyzed using a two phase pressure drop equation and the results show that the impact of viscous IL flow is insignificant compared to the total pumping work. The HFCs studied in this work have very similar structures. However, the extent of solubility and system efficiency in the same IL, [bmim][PF6], made a large difference. Most surprisingly, even when the refrigerant had the same chemical formula, the change in fluorine position in tetrafluoroethane showed significantly different system performance. The symmetrical tetrafluoroethane had superior CE and COP over the asymmetrical tetrafluoroethane most likely due to the higher probability to form hydrogen bonding with the absorbent. The computational results for various HFC/IL pairs show that in selecting the working fluid pairs, the refrigerant should have high overall solubility in the IL and a large gradient of solubility with respect to temperature. Also, refrigerants with small pressure ranges are preferred. In addition to the simulation study, a bench-top absorption refrigeration system was built and operated using IL based working fluids for the first time. The effect of cooling was observed by operating the test system. The experimental results were congruent with the predictions from the modeling work. In conclusion, an absorption refrigeration system based on the IL chemical compressor has been shown to be a promising solution in applications which need efficient cooling and generate abundant waste heat.

The air conditioning systems currently utilized in automobiles are the vapor compression systems. This type of system has many disadvantages: the refrigerant used is not environmentally friendly, the compressor is in competition with the engine coolant system, and the compressor uses a significant portion of the engine power. A waste heat driven absorption refrigeration system is one alternative to the current systems that could address these problems. The absorption refrigeration system uses solutions for the absorbent-refrigerant pair that do not harm the environment. This investigation includes a theoretical analysis of the feasibility of absorption air conditioning system in automotive applications. Also, a comparison of the power requirements of the proposed system and the vapor compression system is performed.

The waste heat recovery technologies have become very relevant since many industrial plants continuously reject large amounts of thermal energy during normal operation which contributes to the increase of the production costs and also impacts the environment. The simulation programs used in industrial engineering enable development and optimization of the operational processes in a cost-effective way. The company Chematur Engineering AB, which supplies chemical plants in many different fields of use on a worldwide basis, was interested in the investigation of the possibilities for effective waste heat recovery from the hydrogenation of dinitrotoluene, which is a sub-process in the toluene diisocyanate manufacture plant. The project objective was to implement waste heat recovery by application of the Organic Rankine Cycle and the Absorption Refrigeration Cycle technologies. Modeling and design of the Organic Rankine Cycle and the Absorption Refrigeration Cycle systems was performed by using Aspen Plus® simulation software where the waste heat carrier was represented by hot water, coming from the internal cooling system in the hydrogenation process. Among the working fluids investigated were ammonia, butane, isobutane, propane, R-123, R-134a, R-227ea, R-245fa, and ammonia-water and LiBr-water working pairs. The simulations have been performed for different plant capacities with different temperatures of the hydrogenation process. The results show that the application of the Organic Rankine Cycle technology is the most feasible solution where the use of ammonia, R-123, R-245fa and butane as the working fluids is beneficial with regards to power production and pay-off time, while R-245fa and butane are the most sustainable choices considering the environment.

Esse trabalho constitui o desenvolvimento da modelagem térmica e simulação por métodos numéricos de dois componentes fundamentais do ciclo de refrigeração por absorção de calor com o par amônia/água: o absorvedor e o gerador. A função do absorvedor é produzir mistura líquida com alta fração mássica de amônia a partir de mistura líquida com baixa fração mássica de amônia e mistura vapor mediante retirada de calor. A função do gerador é produzir mistura líquido/vapor a partir de mistura líquida mediante o fornecimento de calor. É proposto o uso da tecnologia de filmes descendentes sobre placas inclinadas e o método de diferenças finitas para dividir o comprimento da placa em volumes de controle discretos e realizar os balanços de massa, espécie de amônia e energia juntamente com as equações de transferência de calor e massa para o filme descendente. O objetivo desse trabalho é obter um modelo matemático simplificado para ser utilizado em controle e otimização. Esse modelo foi utilizado para calcular as trocas de calor e massa no absorvedor e gerador para diversas condições a partir de dados operacionais, tais como: dimensões desses componentes, ângulo de inclinação da placa, temperatura de superfície e condições de entrada da fase líquida e vapor. Esses resultados foram utilizados para estabelecer relações de causa e efeito entre as variáveis e parâmetros do problema. Os resultados mostraram que o ângulo de inclinação da placa ótimo tanto para o absorvedor como para o gerador é a posição vertical, ou 90°. A posição vertical proporciona o menor comprimento de equilíbrio (0,85 m para o absorvedor e 1,27 m para o gerador com as condições testadas) e se mostrou estável, pois até 75° não foram verificadas variações no funcionamento do absorvedor e gerador. Dentre as condições testadas para uma placa de 0,5 m verificou-se que as maiores efetividades térmicas no absorvedor e gerador foram respectivamente 0,9 e 0,7 e as maiores efetividades mássicas no absorvedor e gerador foram respectivamente 0,6 e 0,5. É esperado que os dados obtidos sejam utilizados em trabalhos futuros para a construção de um protótipo laboratorial e na validação do modelo. / This work presents the development of thermal modeling and simulation by numerical methods of two fundamental components of an ammonia/water heat absorption refrigeration cycle: absorber and generator. The function of the absorber is produce high ammonia mass fraction liquid mixture from low ammonia mass fraction liquid mixture and vapor mixture by heat removal. The function of the generator is produce vapor mixture from liquid mixture by heat addition. It is used the falling film technology over Inclined plates and the finite difference method to slice the plate length in discreet control volumes and do the mass, ammonia specie and energy balances along with the heat and mass transfer equations to the falling film. The aim of this work was obtain a simplified mathematical model to be used in control and optimization. This model was used to calculate the exchanges of heat and mass of both absorber and generator in many conditions from operational data such as: components dimensions, plate angle, surface temperature and inlet condition of liquid and vapor phase. These results were used to establish relations of cause and effect between the problem variables and parameters. The results showed that the optimum plate angle for both absorber and generator is the vertical position, or 90°. The vertical position provides the smallest equilibrium length (0,85 m to the absorber and 1,27 to the generator in tested conditions) and it proves itself to be stable, because until 75° no variations in the function of absorber and generator were detected. Among the tested condition for a 0,5 m plate length the highest thermal effectiveness for absorber and generator were respectively 0,9 and 0,7 and the highest mass effectiveness for absorber and generator were respectively 0,6 and 0,5. The obtained data is expected to be used in future works for the construction of a laboratorial prototype and in the model validation.

A energia é o maior contribuinte para os custos de operação de uma indústria, portanto, estudos para melhoria da eficiência dos sistemas que utilizam alguma fonte de energia são indispensáveis. O presente trabalho tem por objetivo a obtenção de configurações ótimas para satisfazer demandas de eletricidade e cargas térmicas de aquecimento e refrigeração a partir de uma fonte primaria de energia, avaliando o impacto dessas nos custos de produção de eletricidade, vapor e água gelada. Estes tipos de sistemas são conhecidos como sistemas de trigeração. A avaliação de desempenho dos sistemas de trigeração é conduzida através da aplicação da análise exergética e exergoeconômica das alternativas propostas para a determinação do rendimento exergético e custos em base exergética de produção de utilidades desse tipo de sistema. Após apresentar uma breve discussão sobre o uso eficiente e racional de energias primárias e mostrar um panorama da situação para a aplicação de sistemas de trigeração para satisfazer demandas energéticas na indústria e o setor terciário, são descritas diferentes tecnologias envolvidas neste tipo de sistemas e algumas configurações propostas por vários pesquisadores nos anos recentes. O trabalho mostra o impacto das tecnologias de trigeração nos custos em base exergética dos produtos: eletricidade, vapor para processo e água gelada. Sistemas de refrigeração por absorção de efeito simples, duplo efeito e o sistema híbrido de absorção/ejeto compressão são analisados, como parte do estudo dos sistemas de trigeração. Diversos sistemas de trigeração, incluindo o sistema tetra-combinado, são comparados satisfazendo demandas energéticas para três aplicações diferentes: indústria de laticínios, hospital e indústria de bebidas. As configurações em estudo são otimizadas usando o método de algoritmo genético. Os resultados mostram que o sistema de refrigeração híbrido de absorção/ejeto compressão é uma boa alternativa para a produção da água gelada porque o coeficiente de desempenho (COP) e a eficiência exergética são maiores do que no sistema de refrigeração por absorção de efeito simples. Observando o impacto na formação dos custos de conversão de energia para os sistemas de trigeração propostos, os sistemas que utilizam unidade de refrigeração por absorção de duplo efeito são os que apresentam menor impacto. O sistema tetra-combinado apresenta um menor impacto quanto comparado com o ciclo combinado com unidade de refrigeração por absorção de simples efeito. O consumo de combustível e a destruição de exergia dos diferentes sistemas são refletidos nos custos em base exergética dos diferentes produtos. A otimização com algoritmos genéticos mostrou ganhos importantes nos custos em base exergética dos produtos, mediante a maximização da eficiência exergética dos diferentes sistemas de trigeração. O método dos algoritmos genéticos mostra-se como um método robusto para a otimização de sistemas de conversão de energia, mesmo que exija um grande esforço computacional. / Energy is the largest contributor to operating costs of any industry; therefore, studies for improving systems efficiency that use some energy source are essential. This work aims to obtain optimal configurations in order to satisfy required demands for electricity and thermal loads for heating and cooling from a primary source of energy, evaluating the impact of the electricity, steam and chilled water production costs. These types of systems are known as trigeneration systems. The performance evaluation of trigeneration systems is carried out by the application of exergy and exergoeconomic analysis of the proposed alternatives in order to determine exergy efficiency and exergy based costs on production of this type of system utilities. After presenting a brief discussion about efficient and rational use of primary energies and an overview of situation for trigeneration systems application, various technologies involved in this type of systems and some configurations proposed by several authors are described. This research shows the impact of trigeneration technologies in exergy-based costs of products: electricity, steam process and chilled water. Absorption refrigeration systems of simple effect, double effect and the hybrid absorption/ejecto compression are analyzed, as part of the trigeneration systems study. Several trigeneration systems, including the tetra-combined system, are compared with each other, satisfying energetic demands for three different applications: a dairy industry, a hospital and a drinks industry. The configurations in study are optimized using the Genetic Algorithm method. The results show that the hybrid absorption/ejecto compression refrigeration system is a good alternative for chilled water production due to that the coefficient of performance (COP) and the exergetic efficiency are higher than simple effect absorption refrigeration system. Observing the impact in the formation of the energy conversion costs for trigeneration systems proposed, the systems that use a double effect absorption refrigeration system presents the less impact. When tetra-combined system is compared with the system using a simple effect absorption refrigeration system, the results show a reduction in the impact of costs formation. The fuel consumption and exergy destruction of the different systems is reflected in the exergy based costs of the different products. The optimization with genetic algorithms shown important profits in the exergy based costs of products, by means of the exergetic efficiency maximization of the different trigeneration systems. The genetic algorithm method is a robust method for energy conversion systems optimization, even that it demands a great computational effort.

A energia é o maior contribuinte para os custos de operação de uma indústria, portanto, estudos para melhoria da eficiência dos sistemas que utilizam alguma fonte de energia são indispensáveis. O presente trabalho tem por objetivo a obtenção de configurações ótimas para satisfazer demandas de eletricidade e cargas térmicas de aquecimento e refrigeração a partir de uma fonte primaria de energia, avaliando o impacto dessas nos custos de produção de eletricidade, vapor e água gelada. Estes tipos de sistemas são conhecidos como sistemas de trigeração. A avaliação de desempenho dos sistemas de trigeração é conduzida através da aplicação da análise exergética e exergoeconômica das alternativas propostas para a determinação do rendimento exergético e custos em base exergética de produção de utilidades desse tipo de sistema. Após apresentar uma breve discussão sobre o uso eficiente e racional de energias primárias e mostrar um panorama da situação para a aplicação de sistemas de trigeração para satisfazer demandas energéticas na indústria e o setor terciário, são descritas diferentes tecnologias envolvidas neste tipo de sistemas e algumas configurações propostas por vários pesquisadores nos anos recentes. O trabalho mostra o impacto das tecnologias de trigeração nos custos em base exergética dos produtos: eletricidade, vapor para processo e água gelada. Sistemas de refrigeração por absorção de efeito simples, duplo efeito e o sistema híbrido de absorção/ejeto compressão são analisados, como parte do estudo dos sistemas de trigeração. Diversos sistemas de trigeração, incluindo o sistema tetra-combinado, são comparados satisfazendo demandas energéticas para três aplicações diferentes: indústria de laticínios, hospital e indústria de bebidas. As configurações em estudo são otimizadas usando o método de algoritmo genético. Os resultados mostram que o sistema de refrigeração híbrido de absorção/ejeto compressão é uma boa alternativa para a produção da água gelada porque o coeficiente de desempenho (COP) e a eficiência exergética são maiores do que no sistema de refrigeração por absorção de efeito simples. Observando o impacto na formação dos custos de conversão de energia para os sistemas de trigeração propostos, os sistemas que utilizam unidade de refrigeração por absorção de duplo efeito são os que apresentam menor impacto. O sistema tetra-combinado apresenta um menor impacto quanto comparado com o ciclo combinado com unidade de refrigeração por absorção de simples efeito. O consumo de combustível e a destruição de exergia dos diferentes sistemas são refletidos nos custos em base exergética dos diferentes produtos. A otimização com algoritmos genéticos mostrou ganhos importantes nos custos em base exergética dos produtos, mediante a maximização da eficiência exergética dos diferentes sistemas de trigeração. O método dos algoritmos genéticos mostra-se como um método robusto para a otimização de sistemas de conversão de energia, mesmo que exija um grande esforço computacional. / Energy is the largest contributor to operating costs of any industry; therefore, studies for improving systems efficiency that use some energy source are essential. This work aims to obtain optimal configurations in order to satisfy required demands for electricity and thermal loads for heating and cooling from a primary source of energy, evaluating the impact of the electricity, steam and chilled water production costs. These types of systems are known as trigeneration systems. The performance evaluation of trigeneration systems is carried out by the application of exergy and exergoeconomic analysis of the proposed alternatives in order to determine exergy efficiency and exergy based costs on production of this type of system utilities. After presenting a brief discussion about efficient and rational use of primary energies and an overview of situation for trigeneration systems application, various technologies involved in this type of systems and some configurations proposed by several authors are described. This research shows the impact of trigeneration technologies in exergy-based costs of products: electricity, steam process and chilled water. Absorption refrigeration systems of simple effect, double effect and the hybrid absorption/ejecto compression are analyzed, as part of the trigeneration systems study. Several trigeneration systems, including the tetra-combined system, are compared with each other, satisfying energetic demands for three different applications: a dairy industry, a hospital and a drinks industry. The configurations in study are optimized using the Genetic Algorithm method. The results show that the hybrid absorption/ejecto compression refrigeration system is a good alternative for chilled water production due to that the coefficient of performance (COP) and the exergetic efficiency are higher than simple effect absorption refrigeration system. Observing the impact in the formation of the energy conversion costs for trigeneration systems proposed, the systems that use a double effect absorption refrigeration system presents the less impact. When tetra-combined system is compared with the system using a simple effect absorption refrigeration system, the results show a reduction in the impact of costs formation. The fuel consumption and exergy destruction of the different systems is reflected in the exergy based costs of the different products. The optimization with genetic algorithms shown important profits in the exergy based costs of products, by means of the exergetic efficiency maximization of the different trigeneration systems. The genetic algorithm method is a robust method for energy conversion systems optimization, even that it demands a great computational effort.

Orientador: Silvia Azucena Nebra de Perez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-11T16:10:36Z (GMT). No. of bitstreams: 1 PalaciosBereche_Reynaldo_M.pdf: 8960679 bytes, checksum: a6e8e552788d00fa0fb258923ebe13a9 (MD5) Previous issue date: 2008 / Resumo: Neste trabalho e feita uma revisão em relação à participação do gás natural na matriz energética mundial, brasileira e no Estado de São Paulo. Características do setor terciário, assim como da utilização do gás natural neste setor de consumo, são apresentadas também na primeira parte. Foi feita uma revisão das tecnologias de utilização de gás natural no setor terciário, assim como da tecnologia dos sistemas de refrigeração por absorção, das diferentes configurações do ciclo, e dos fluidos de trabalho utilizados neste tipo de sistema. Uma metodologia para o calculo da exergia da solução água brometo de lítio, comumente utilizada como fluido de trabalho em sistemas de refrigeração por absorção para condicionamento de ambientes, foi elaborada. Para a realização das analises exegética e exergoeconomica do sistema foi realizado o calculo da exergia total dos fluidos de trabalho considerando as parcelas de exergia química e física. A analise exegética compreendeu o calculo da irreversibilidade em cada componente do sistema assim como da total. Na ultima parte do trabalho foi realizada a analise termodinâmica, exegética e exergoeconomica do sistema de refrigeração por absorção de simples e duplo efeito H2O/LiBr, considerando como fontes de aquecimento um sistema de queima direta de gás natural e energia de rejeito de um sistema de cogeração. Os resultados são comparados e discutidos / Abstract: A review about the participation of the natural gas in the energetic matrix was done in this work, considering the scope international, Brazilian and the Sao Paulo State. Characteristics of the tertiary sector and the natural gas utilization in this consumption sector are also presented. A review about the technologies of utilization of natural gas in the tertiary sector was also done. In the following part, the technology of absorption refrigeration systems, different configurations of the cycle and working fluids were reviewed. A methodology for the exergy calculation of the lithium bromide ¿ water solution was elaborated. The lithium bromide ¿ water solution is widely utilized as working fluid in absorption refrigeration system for air conditioning. The exergy calculation takes in account the chemical and physical parcel of the exergy, which is important to realize the exergetic and exergoeconomic analysis of the system. In the last part of the work it was done a thermodynamic, exergetic and exergoeconomic analysis of the absorption refrigeration system H2O/LiBr of single and double effect. The exergetic analysis included the irreversibility calculation in each component and the total irreversibility of the system. Two different energy sources were considered: direct heating through natural gas combustion and the utilization of rejected energy in a cogeneration system. The different results were compared. / Mestrado / Mestre em Planejamento de Sistemas Energéticos

Esse trabalho constitui o desenvolvimento da modelagem térmica e simulação por métodos numéricos de dois componentes fundamentais do ciclo de refrigeração por absorção de calor com o par amônia/água: o absorvedor e o gerador. A função do absorvedor é produzir mistura líquida com alta fração mássica de amônia a partir de mistura líquida com baixa fração mássica de amônia e mistura vapor mediante retirada de calor. A função do gerador é produzir mistura líquido/vapor a partir de mistura líquida mediante o fornecimento de calor. É proposto o uso da tecnologia de filmes descendentes sobre placas inclinadas e o método de diferenças finitas para dividir o comprimento da placa em volumes de controle discretos e realizar os balanços de massa, espécie de amônia e energia juntamente com as equações de transferência de calor e massa para o filme descendente. O objetivo desse trabalho é obter um modelo matemático simplificado para ser utilizado em controle e otimização. Esse modelo foi utilizado para calcular as trocas de calor e massa no absorvedor e gerador para diversas condições a partir de dados operacionais, tais como: dimensões desses componentes, ângulo de inclinação da placa, temperatura de superfície e condições de entrada da fase líquida e vapor. Esses resultados foram utilizados para estabelecer relações de causa e efeito entre as variáveis e parâmetros do problema. Os resultados mostraram que o ângulo de inclinação da placa ótimo tanto para o absorvedor como para o gerador é a posição vertical, ou 90°. A posição vertical proporciona o menor comprimento de equilíbrio (0,85 m para o absorvedor e 1,27 m para o gerador com as condições testadas) e se mostrou estável, pois até 75° não foram verificadas variações no funcionamento do absorvedor e gerador. Dentre as condições testadas para uma placa de 0,5 m verificou-se que as maiores efetividades térmicas no absorvedor e gerador foram respectivamente 0,9 e 0,7 e as maiores efetividades mássicas no absorvedor e gerador foram respectivamente 0,6 e 0,5. É esperado que os dados obtidos sejam utilizados em trabalhos futuros para a construção de um protótipo laboratorial e na validação do modelo. / This work presents the development of thermal modeling and simulation by numerical methods of two fundamental components of an ammonia/water heat absorption refrigeration cycle: absorber and generator. The function of the absorber is produce high ammonia mass fraction liquid mixture from low ammonia mass fraction liquid mixture and vapor mixture by heat removal. The function of the generator is produce vapor mixture from liquid mixture by heat addition. It is used the falling film technology over Inclined plates and the finite difference method to slice the plate length in discreet control volumes and do the mass, ammonia specie and energy balances along with the heat and mass transfer equations to the falling film. The aim of this work was obtain a simplified mathematical model to be used in control and optimization. This model was used to calculate the exchanges of heat and mass of both absorber and generator in many conditions from operational data such as: components dimensions, plate angle, surface temperature and inlet condition of liquid and vapor phase. These results were used to establish relations of cause and effect between the problem variables and parameters. The results showed that the optimum plate angle for both absorber and generator is the vertical position, or 90°. The vertical position provides the smallest equilibrium length (0,85 m to the absorber and 1,27 to the generator in tested conditions) and it proves itself to be stable, because until 75° no variations in the function of absorber and generator were detected. Among the tested condition for a 0,5 m plate length the highest thermal effectiveness for absorber and generator were respectively 0,9 and 0,7 and the highest mass effectiveness for absorber and generator were respectively 0,6 and 0,5. The obtained data is expected to be used in future works for the construction of a laboratorial prototype and in the model validation.