Neste estudo foi observada a eficiência do sistema de pré-resfriamento em imersão em água na redução da contagem de bactérias mesófilas aeróbias, coliformes totais, coliformes a 45°C e Escherichia coli presentes na carcaça de frango. Avaliou-se a contagem destes microrganismos na água do pré-chiller e chiller, e também foram controlados a temperatura da água do sistema de resfriamento, sua vazão de água de renovação, pH e nível de cloro. O trabalho foi realizado em um matadouro-frigorífico sob inspeção federal localizado no Estado do Rio Grande do Sul. Foram coletadas amostras de carcaças em três horários representando o início, meio e final do turno de abate de oito horas sendo 270 amostras de frango antes da entrada no pré-chiller e 270 amostras após a saída do chiller. Os resultados obtidos mostraram que houve uma redução significativa (p<0,05) na contagem de mesófilos aeróbios da carcaça após passagem pela etapa de resfriamento por imersão em todos os horários de coleta. Igual resultado observou-se para a pesquisa de coliformes totais. Na pesquisa de coliformes fecais houve redução significativa (p<0,05) na segunda e terceira hora de coleta; entretanto, para a pesquisa de E. coli houve redução significativa (p<0,05) na primeira e terceira hora. / In this study, the efficacy of pre-chiller and chiller were evaluated, through the analysis of the mesophilic bacteria counting reduction, total coliforms, 45°C coliforms, and Escherichia coli present on the poultry carcass. The counting of microorganisms in the pre-chiller and chiller’s water was also evaluated, and the water temperature, the outflow, pH and the chlorine level. The study was carried out in a poultry processing plant located in the State of Rio Grande do Sul (Southern Brazil), under official inspection. Carcass samples were collected in three different times corresponding to beginning, middle, and ending of an eight hour processing shift. Two hundred and seventy (270) carcass samples were collected before the pre-chiller entry, while other 270 were collected after the chiller exit. The results showed that there was a significant reduction (p<0,05) in the counting of mesophilic bacteria after chiller in all sampling times. The same result was observed regarding the total coliform counting. The analysis of the 45°C coliforms indicated that there was a significant reduction (p<0,05) at second and third sample collecting times; however, a significant reduction (p<0,05) was found in the counting of E. coli at the first and third hour.

Neste estudo foi observada a eficiência do sistema de pré-resfriamento em imersão em água na redução da contagem de bactérias mesófilas aeróbias, coliformes totais, coliformes a 45°C e Escherichia coli presentes na carcaça de frango. Avaliou-se a contagem destes microrganismos na água do pré-chiller e chiller, e também foram controlados a temperatura da água do sistema de resfriamento, sua vazão de água de renovação, pH e nível de cloro. O trabalho foi realizado em um matadouro-frigorífico sob inspeção federal localizado no Estado do Rio Grande do Sul. Foram coletadas amostras de carcaças em três horários representando o início, meio e final do turno de abate de oito horas sendo 270 amostras de frango antes da entrada no pré-chiller e 270 amostras após a saída do chiller. Os resultados obtidos mostraram que houve uma redução significativa (p<0,05) na contagem de mesófilos aeróbios da carcaça após passagem pela etapa de resfriamento por imersão em todos os horários de coleta. Igual resultado observou-se para a pesquisa de coliformes totais. Na pesquisa de coliformes fecais houve redução significativa (p<0,05) na segunda e terceira hora de coleta; entretanto, para a pesquisa de E. coli houve redução significativa (p<0,05) na primeira e terceira hora. / In this study, the efficacy of pre-chiller and chiller were evaluated, through the analysis of the mesophilic bacteria counting reduction, total coliforms, 45°C coliforms, and Escherichia coli present on the poultry carcass. The counting of microorganisms in the pre-chiller and chiller’s water was also evaluated, and the water temperature, the outflow, pH and the chlorine level. The study was carried out in a poultry processing plant located in the State of Rio Grande do Sul (Southern Brazil), under official inspection. Carcass samples were collected in three different times corresponding to beginning, middle, and ending of an eight hour processing shift. Two hundred and seventy (270) carcass samples were collected before the pre-chiller entry, while other 270 were collected after the chiller exit. The results showed that there was a significant reduction (p<0,05) in the counting of mesophilic bacteria after chiller in all sampling times. The same result was observed regarding the total coliform counting. The analysis of the 45°C coliforms indicated that there was a significant reduction (p<0,05) at second and third sample collecting times; however, a significant reduction (p<0,05) was found in the counting of E. coli at the first and third hour.

Neste estudo foi observada a eficiência do sistema de pré-resfriamento em imersão em água na redução da contagem de bactérias mesófilas aeróbias, coliformes totais, coliformes a 45°C e Escherichia coli presentes na carcaça de frango. Avaliou-se a contagem destes microrganismos na água do pré-chiller e chiller, e também foram controlados a temperatura da água do sistema de resfriamento, sua vazão de água de renovação, pH e nível de cloro. O trabalho foi realizado em um matadouro-frigorífico sob inspeção federal localizado no Estado do Rio Grande do Sul. Foram coletadas amostras de carcaças em três horários representando o início, meio e final do turno de abate de oito horas sendo 270 amostras de frango antes da entrada no pré-chiller e 270 amostras após a saída do chiller. Os resultados obtidos mostraram que houve uma redução significativa (p<0,05) na contagem de mesófilos aeróbios da carcaça após passagem pela etapa de resfriamento por imersão em todos os horários de coleta. Igual resultado observou-se para a pesquisa de coliformes totais. Na pesquisa de coliformes fecais houve redução significativa (p<0,05) na segunda e terceira hora de coleta; entretanto, para a pesquisa de E. coli houve redução significativa (p<0,05) na primeira e terceira hora. / In this study, the efficacy of pre-chiller and chiller were evaluated, through the analysis of the mesophilic bacteria counting reduction, total coliforms, 45°C coliforms, and Escherichia coli present on the poultry carcass. The counting of microorganisms in the pre-chiller and chiller’s water was also evaluated, and the water temperature, the outflow, pH and the chlorine level. The study was carried out in a poultry processing plant located in the State of Rio Grande do Sul (Southern Brazil), under official inspection. Carcass samples were collected in three different times corresponding to beginning, middle, and ending of an eight hour processing shift. Two hundred and seventy (270) carcass samples were collected before the pre-chiller entry, while other 270 were collected after the chiller exit. The results showed that there was a significant reduction (p<0,05) in the counting of mesophilic bacteria after chiller in all sampling times. The same result was observed regarding the total coliform counting. The analysis of the 45°C coliforms indicated that there was a significant reduction (p<0,05) at second and third sample collecting times; however, a significant reduction (p<0,05) was found in the counting of E. coli at the first and third hour.

With the objectives of designing a solar cooling system with cold storage unit for the Iraqi climate, solar energy resources were assessed and methods were proposed to enhance harvesting the solar energy in the Iraqi climate. Where the results showed that adopting monthly average optimal tilt angles led to an increase in the amount of useful solar energy gained nearly 9%. A methodology of multi objective optimisation of solar absorption cooling system was then developed and demonstrated by applying it in a domestic application in Baghdad. Maximising the system performance in exergy, economic and environment were the objectives of the project. A decision-making tool was then implemented to select the most suitable design. The optimal proposed system has exergy efficiency of 56%, total cost rate of 4.19US$/hr, annual CO2 emission of 32199kg and payback period of 18.7years. After analysing the optimal configuration of the system, a cold thermal energy storage unit with the solar absorption cooling system was suggested in order to store the cold energy produced by the system at times when the solar energy is available (at daytime) and use (discharge) it at times when there is no solar energy available (at night). Next, a new control strategy was developed and applied in the system to make it more cost effective. Five scenarios were considered to manage the quantity of charging of the cold storage tank according to the splitting rate of the mass of the supplied chilled water by the chiller to the cold storage tank and the building. Finally, the chosen optimal system that uses an efficient controlled cold thermal energy storage, has exergy efficiency of 69.4%, total cost rate of 4.25US$/hr and total avoided annual CO2 emissions of 33.9% less than system without cold storage tank. Additionally, without any government incentive, the payback was recorded 9.3years, which was 50% less than the system without cold storage tank.

The topic of this diploma thesis is to design water chiller for ceiling cooling system. The thesis is divided into four main parts. The first part deals with the theoretical description of emitting cooling systems. The following part focuses on the theory of refrigerating systems and describes especially the thermal cycle and refrigerants which are used in cooling systems. In the third chapter refrigerating equipment are described. Compressor, heat exchangers and expansion valves belong to the main parts of refrigerating systems. The final chapter is devoted to the draft and selection of components of the refrigerating system.

Absorption cooling system driven by district heating network is relized as a smart strategy in Sweden. During summer time when the heating demand is low, the excessive hot water can be directly sold to drive absorption chillers instead of decreasing its production. In addition, this is also one answer to satisfy the cooling demand in more environmentally way since currently only around 26% of cooling demand in Sweden is satisfied by district cooling, the rest is fulfilled by individual air conditioning. Realizing this potential, the purpose of this study is to examine the returning hot water temperature in the district heating network with supply temperature of 70°C and also the effect to the absorption chiller’s COP. Through the simulation result, it is found out that the lowest possible returning water temperature is 55 °C at COP 0,69 with heat rejection (re-cooling) temperature water at 22 °C. This implies that the desired returning hot water temperature of 47 °C cannot be achieved. The lower returning hot water temperature is preferable since it gives the district heating network benefit in term of less distribution pump work, and energy recovery for the condensation process at central heating plant.

In this study a roof-top PVT/absorption chiller system is modeled for a hotel building in Antalya, Turkey to cover the cooling demand of the hotel, to produce electricity and domestic hot water. PVT modules, an absorption chiller, a hot storage tank and a natural gas fired auxiliary heater are the main components of the system. Elecetrical power produced by the system is 94.2 MWh, the cooling power is 185.5 MWh and the amount of domestic hot water produced in the system is 65135 m3 at 45 0C annually.  Even though the systems is capable of meeting the demands of the hotel building, because of the high investment costs of PVT modules and high interest rates in Turkey, it is not economically favorable. Using cheaper solar collectors, integrating a cold storage unit in the system or having an improved conrol strategy are the options to increase the system efficiency and to make the system economically competitive.

No description available.

This study explores the application of micro-CCHP systems that utilize a 30 kW gas microturbine and an absorption chiller. Engineering Equation Solver (EES) is used to model a novel single-effect and double-effect water-lithium bromide absorption chiller that integrates the heat recovery unit and cooling tower of a conventional CCHP system into the chiller’s design, reducing the cost and footprint of the system. The results of the EES model are used to perform heat and material balances for the micro-CCHP systems employing the novel integrated chillers, and energy budgets for these systems are developed. While the thermal performance of existing CCHP systems range from 50-70%, the resulting thermal performance of the new systems in this study can double those previously documented. The size of the new system can be significantly reduced to less than one third the size of the existing system.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-20T14:17:58Z No. of bitstreams: 1 Ronaldo Bueno de Souza.pdf: 1999281 bytes, checksum: 5dd2b3645a9e4750a12f291e30ba6d41 (MD5) / Made available in DSpace on 2015-07-20T14:17:58Z (GMT). No. of bitstreams: 1 Ronaldo Bueno de Souza.pdf: 1999281 bytes, checksum: 5dd2b3645a9e4750a12f291e30ba6d41 (MD5) Previous issue date: 2015-04-07 / CYTED - Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo / Este trabalho apresenta o estudo de um sistema de refrigeração por absorção assistido por energia solar térmica com intuito de ser empregado no arrefecimento de uma pousada de ecoturismo localizada em um local remoto, desprovida de conexão à rede elétrica. Para o estudo do sistema proposto foi utilizado o software de simulações TRNSYS, onde em uma etapa inicial do trabalho foi realizada a comparação dos resultados do software com os resultados dos modelos matemáticos dos componentes do sistema de refrigeração. Foi desenvolvido um modelo computacional, para realização de simulações horárias que permitiu a simulação de três configurações de sistemas de refrigeração por absorção, podendo assim determinar a influência dos componentes e parâmetros utilizados no sistema no uso da energia auxiliar e no atendimento da carga térmica. O primeiro modelo é constituído por um sistema onde a água aquecida pelo coletor solar térmico e é armazenada em um reservatório térmico, sendo a mesma utilizada para a alimentação do chiller de absorção. A água gelada produzida pelo chiller é armazenada em outro reservatório térmico onde fica disponível para o consumo. Neste modelo observa-se que com o uso de 120 m² de coletores de tubo evacuado chega-se a índices de atendimento dos consumos superiores a 87 %. O segundo modelo é similar ao primeiro, com a inclusão de um aquecedor auxiliar para a água de alimentação do chiller de absorção. Neste modelo observou-se que com o uso de 120 m² de coletores de placas planas chega-se a um consumo de energia auxiliar inferior a 195 GJ, e com o uso de 120 m² de coletores de tubo evacuado chega-se a um consumo de energia auxiliar inferior a 150 GJ. O terceiro modelo é similar ao segundo, onde foi acrescentado um sistema para utilização da água de arrefecimento do chiller de absorção, para uso no consumo de água quente para banho, nos chuveiros. Neste modelo observa-se que o aproveitamento da água de arrefecimento não afeta o consumo de energia auxiliar, se comparado com o consumo do segundo modelo. / This paper presents the study of a cooling system for absorption assisted by solar energy with a view to be used in the cooling of an ecotourism lodge located in a remote location, devoid of connection to the grid. To study the proposed system was used TRNSYS simulation software, where in an initial work step of comparing software results with the results of mathematical models of the components of the refrigeration system is performed. A computer model was developed to perform simulations slot which simulated three configurations absorption refrigeration systems and can therefore determine the influence of the components and system parameters used in the auxiliary power usage and meet the thermal load. The first model is made up of a system where the water heated by the solar thermal collector and is stored in a thermal storage tank, being the same used for feeding the absorption chiller. The chilled water produced by the chiller is stored in another thermal reservoir where it is available for consumption. In this model it is observed that with the use of 120 m² evacuated tube collectors comes to fuel consumption attendance rates of over 87 %. The second model is similar to the first, with the inclusion of an auxiliary heater to supply water from the absorption chiller. In this model we found that with the use of 120 m² of flat plate collectors comes to an auxiliary power consumption of less than 195 GJ, and with the use of 120 m² evacuated tube collectors we arrive at a consumption of auxiliary power less than 150 GJ. The third model is similar to the second, which was added to a system using the cooling water from absorption chiller for use in the consumption of hot water for baths, showers on. In this model, it is observed that the use of the cooling water does not affect the auxiliary power consumption compared with the consumption of the second model.