abstract: As additive manufacturing grows as a cost-effective method of manufacturing, lighter, stronger and more efficient designs emerge. Heat exchangers are one of the most critical thermal devices in the thermal industry. Additive manufacturing brings us a design freedom no other manufacturing technology offers. Advancements in 3D printing lets us reimagine and optimize the performance of the heat exchangers with an incredible design flexibility previously unexplored due to manufacturing constraints. In this research, the additive manufacturing technology and the heat exchanger design are explored to find a unique solution to improve the efficiency of heat exchangers. This includes creating a Triply Periodic Minimal Surface (TPMS) geometry, Schwarz-D in this case, using Mathematica with a flexibility to control the cell size of the models generated. This model is then encased in a closed cubical surface with manifolds for fluid inlets and outlets before 3D printed using the polymer nylon for thermal evaluation. In the extent of this study, the heat exchanger developed is experimentally evaluated. The data obtained are used to derive a relationship between the heat transfer effectiveness and the Number of Transfer Units (NTU).The pressure loss across a fluid channel of the Schwarz D geometry is also studied. The data presented in this study are part of initial experimental evaluation of 3D printed TPMS heat exchangers.Among heat exchangers with similar performance, the Schwarz D geometry is 32% smaller compared to a shell-and-tube heat exchanger. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2018

Orientador: Elias Basile Tambourgi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T04:26:11Z (GMT). No. of bitstreams: 1 Silva_ThadeuAlfredoFarias_M.pdf: 5396797 bytes, checksum: fb0ca3ed2816b12c4c4ee60aeceb38e7 (MD5) Previous issue date: 2012 / Resumo: Este trabalho apresenta o dimensionamento e cálculos do trocador de calor duplo-tubo de cotato indireto e troca direta, aplicado nas instalações dos geradores elétricos a combustão, com o objetivo de analisar a viabilidade de um projeto para tratamento do ar quente gerado dentro das estruturas metálicas ou canópias. Os dados coletados basearam-se no levantamento de registros de temperatura internas e externas dos geradores, velocidade, pressão e vazão do ar quente nos dutos de saída e por último a utilização de equações da termodinâmica para obtenção dos resultados. Acrescentam-se ainda aos cálculos as propriedades dos fluidos, as dimensões dos tubos e as propriedades térmicas da tubulação do aço, materiais estes utilizados na sua construção. Comparadas as curvas de registros levantadas, obteve-se as temperaturas médias de entrada e saída e interna do motor com média de 27,694°C, 40,814°C e 33,383°C, respectivamente. No caso das curvas de registros da vazão e a diferença de pressão apresentaram pouca oscilação, sendo consideradas como constantes e iguais a 20,496 m3/h e 80,138 Pa, respectivamente. Após os balanços energéticos, o trocador de calor de duplo-tubo ficou determinado como sendo: diâmetro do tubo interno 3 ½ polegada e diâmetro do tubo externo de 6 polegadas, ambos de aço carbono com 13,52 pés de comprimento linear de troca de calor. Usando uma vazão de 1,4 m3/h de água a 23°C, obteve-se uma taxa de troca de calor no sistema de 0,4719 Btu/h. A contribuição deste trabalho é possível com a determinação da taxa de calor trocada no sistema do trocador de calor e assim garantir-se que esta opção de instalação pode ser controlada para obter-se a atenuação térmica interna nos grupos geradores de energia / Abstract: This paper presents the design and calculation of the heat exchanger double-tube indirect and direct exchange, applied on the premises of the combustion electric generators, in order to analyze the feasibility of a project for the treatment of hot air generated within the metal structures or canopies. The data collected were based on survey records of internal and external temperature of generators, speed, pressure and flow of hot air in the ducts output and finally the use of equations of thermodynamics to obtain the results. It is further added to the calculations the fluid properties, the dimensions of the pipes and the thermal properties of the steel pipe, these materials used in its construction. Comparing the curves of records raised, there was obtained the average temperatures of the inlet and outlet and the internal engine ° C mean 27.694, 40.814 ° C to 33.383 ° C, respectively. In the case of records of flow curves and pressure difference showed little change, being considered as constant and equal to 20.496 80.138 m3/he Pa, respectively. After the energy balances the heat exchanger double-tube was determined to be: diameter of the inner tube 3 ½ inch diameter and 6 inch outer tube, both made of carbon steel with 13.52 feet long linear heat exchange . Using a flow rate of 1.4 m3 / h of water at 23 ° C, there was obtained a rate of heat exchange in the system of 0.4719 Btu / hr. The contribution of this work it is possible to determine the rate of heat exchanged in the heat exchanger system and ensure that there is attenuation in internal thermal energy generators / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Crude oil distillation is an energy intensive and environmentally challenging process. To decrease the large energy demand of crude oil distillation, heat integration is implemented. The system (i.e. distillation unit and heat exchanger network, HEN) needs to perform an energy-efficient separation in a broad range of scenarios (e.g. changes in product yields or product specifications), without compromising overall profit. Operational optimisation and revamp projects are frequently implemented to adapt an existing system to such diverse scenarios. The present work provides a new approach for optimising crude oil distillation systems. The scope of this methodology consists of: 1) finding the operating conditions for the distillation system that maximise net profit, while 2) proposing retrofit modifications for the HEN that allow a feasible operation. Artificial neural networks (ANN) are used to represent the distillation process. In the proposed modelling strategy, results of rigorous simulations provide the data used to train the ANN models. The resulting ANN models have the advantages of overcoming convergence problems presented by both rigorous and simplified models, of handling fewer variables and performing calculations in less time. The HEN models used in this work consist of a retrofit model and a simulation model. The HEN retrofit model employed by Chen (2008) is extended to include constraints on heat transfer areas, utility consumption; and to optimise stream split fractions. In addition, the segmented linear data used by Chen (2008) to calculate temperature-dependent heat capacities are replaced by models tailor-made for each stream. This allows a more flexible and accurate representation of these properties, compared to the approach of Chen (2008). The HEN simulation model of de Oliveira Filho et al. (2007) is modified and extended in this work to simulate simple unit operations and to consider heat exchangers specified in terms of heat loads. Distillation, HEN and economic models are implemented in a two-level optimisation framework. The first level consists of a simulated annealing algorithm that optimises the operating conditions of the distillation unit (e.g. flow rates of products and stripping steam, pump-around duties and temperature drops, furnace exit temperature) and HEN topology (i.e. number and location of heat exchangers and stream splitters). The second level solves a non-linear least squares problem that addresses the violation of HEN constraints. Different objective functions can be considered, such as maximising net profit or minimising total annualised costs. The case studies presented in this work show that ANN models are suitable for their implementation in optimisation methodologies for crude oil distillation systems. Results indicate that interactions between the distillation process and HEN are captured, and that significant economic improvements can be achieved with the proposed optimisation approach.

Orientador: Carlos Teofilo Salinas Sedano / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T04:21:17Z (GMT). No. of bitstreams: 1 Armengol_JanMateu_M.pdf: 6999606 bytes, checksum: e35806586b55eb3f8f1b370625009ba8 (MD5) Previous issue date: 2015 / Resumo: Neste trabalho é apresentado um modelo para a formação de gelo poroso entre placas planas paralelas baseado em um novo tratamento bidimensional da taxa de crescimento. O modelo considera as equações de transporte de quantidade de movimento, energia e massa. Para a resolução do modelo, as equações são discretizadas usando o método de volumes finitos em um domínio bidimensional composto por ar e gelo poroso. A interface móvel ar-gelo é tratada utilizando a formulação de malha fixa. O domínio computacional inclui a região frontal das placas planas com a finalidade de estudar o crescimento do gelo poroso nessa região. O código numérico é verificado por partes de acordo com artigos de referência na literatura e o modelo é validado com dados experimentais. Os dados experimentais, reportando temperatura e crescimento de forma locais, coincidem com os resultados numéricos com um erro relativo inferior a 10 \% para o caso intermediário de taxa de umidade / Abstract: In this study, a frost formation model is presented based on a new two-dimensional approach for the growth rate. For modeling the frost formation over parallel cold plates, the basic transport equations of mass, energy and momentum have been discretized using the finite volume method in a two-dimensional domain in which air and frost are considered. A volume tracking method employing a fixed grid formulation is used to deal with the air-frost moving boundary. An extended domain in the inlet boundary has been considered in order to study the frost formation in the leading edge of the plate. The numerical code is gradually verified using benchmarking references. The numerical results have been validated against experimental data in which frost growth and temperature as a function of time are reported as local values. The model predictions of the frost thickness as a function of time agree with the experimental data within 10 \% of deviation for the case of intermediate humidity ratio / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

The aim of this thesis is to design a surface condenser with lateral exhaust. A research in the field of surface condensers with lateral exhaust takes place before the design. Core of the thesis is a thermodynamic design of the heat exchanger, calculation of pressure losses on the side of coolant water, check of the tube bundles from standpoint of oscillation and a design of air removal pipeline. Finally a design of the condenser is supported with a drawing attached in the supplement.

7ABSTRACTAs the energy consumption for thermal comfort and space cooling around the world continues to grow due to a steadily increasing demand and climate change; the use of vapor compression technology, has increased significantly. In this technology, condensation is used to condense out the water vapor from air by maintaining the coils at a cooler temperature than required to meet the sensible load. This results in a high energy consumption for dehumidification and lowers the overall efficiency of the system. They also pose environmental threats due to its significant CO2 emissions.<div><br></div><div>The aim of this research is to address the above problems by using a novel membrane configuration called as a membrane heat exchanger that has integrated cooling coils and simultaneously cools and dehumidifies the air stream with the help of a vacuum pump and a vapor selective membrane.</div><div><br></div><div>In this work, the CFD modeling and design of a membrane heat exchanger is presented. The model is developed for a base case to study the heat and mass transfer performance of the system. The model after validation with existing studies is developed further to obtain several contour plots to understand the effects of concentration polarization, membrane permeance, Reynolds number, pressure drop and other design parameters on the performance of the system.<br><div><br></div></div>

GSHP (Ground source heat pump), uses geothermal energy which is a form of green and sustainable energy.  Geothermal energy is also a continuous source of energy, unlike wind energy. The results from this thesis work will be applicable for both GSHP that are being used for space heating, and the ones which have a bottom organic Rankine cycle. The bottom organic Rankine cycle and continuous energy production of GSHP make it a potential source for electricity generation.  The GSHP is of various types, in regard to the configuration of the pipe and their setup in the ground and also based on their grouting. In this study only vertical GSHP and with a single u-tube and water filled grout will be analyzed. The GSHP performance is based on a number of parameters including, the depth of the heat exchanging unit in the ground, other key dimensions of the unit like diameter and outer wall thickness, the fluid flow, and the type of working fluid. Therefore it becomes necessary to study the effect of all of these parameters individually and their individual effect on the energy output and the performance of the BHE. One of the thesis objectives is to establish a sensitivity analysis of the BHE based on the above mention parameters and then further optimize the design with the heat enhancement devices. The major findings of this thesis work are how shank spacing (spacing between the inlet and the outlet pipe) affects the heat transfer in the BHE. The shank spacing seems to reduce the energy output of the GSHP, this is contrary to the high conductive solid grout, where the shank spacing doesn't affect the BHE so much. The diameter of the BHE in the water-filled grout has a completely opposite effect from the solid grout. Increasing the depth of the BHE after a certain length only increases the entropy of the system which reduces the energy output. The working fluid with a higher Prandtl number helps in higher energy output. The optimization results suggest that having a deeper borehole is not very energy efficient in spite of the greater thermal gradient available at a higher depth.

No description available.

The expansion of the use of geothermal heat pumps makes the study of their performances a keystone in their development. Several parameters are crucial to design properly a geothermal heat pump. Comparing the theoretical characteristics of a system with the actual ones one the field is part of its understanding.  This Master thesis gives a closer look for determining from filed data two central parameters, the borehole thermal  resistance  and  the  ground  thermal  conductivity,  using  a  newly  developed  technique  called Distributed Thermal Response Testing (DTRT). These calculations are applied to a U-pipe heat exchanger installed  in  a  private  household.  From  these  two  parameters,  it  is  possible  to  estimate  the  thermal conductivity of the filling material inside the borehole and thus estimate its influence on the performances of  the  system.  Three  grouting  material  are  studied  here  and  theoretical  values  are  compared  with experimental value in order to try to get a picture of the inside of the borehole.  This  thesis  provides  a  picture  of  the  actual  thermal  parameters  of  the  studied  borehole,  which  clearly reveals the influence of the grouting material in each layer. It is also noticed that the laboratory value of the grout thermal conductivities varies when comparing with theoretical values or manufacturer data. The lack of understanding of the actual drying state of the grouts inside the borehole may by one reason why.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / The recent climate change has forced people to live in extreme conditions, either excessive heat or cold, implying that they must adapt to survive in these situations. However, there are people who, because of their geographical condition and lack of resources, lack the means and tools to combat these climate changes. The context of this study is provided in a rural town located in the Arequipa region (Peru), whose inhabitants have to fight against frosts of up to −20 °C in an area without electricity. A viable solution to this problem is found through the design and implementation of a heating system using geothermal and photovoltaic energy, which are resources found in the area, according to a report of the Ministry of Energy and Mines. This study analyzes and researches the geographical and meteorological conditions of the region, for validating, through theory and simulations, whether the proposed system can supply the thermal energy required to maintain the indoor temperature at a minimum of 15 °C under extreme conditions. The system is designed after analyzing the best technological options and techniques currently available in the context studied for its ultimate financing and establishing guidelines and indicators for monitoring results.