Dissertations / Theses on the topic 'Heat application'
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1
Oishi, Tomomi. "Layered heat flux gauges for aeroentry application." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/289901.
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A layered heat flux gauge, which can withstand a high temperature environment for applications such as for use on thermal protection shields on aeroentry vehicles, is analyzed, designed, fabricated, and tested. The heat flux gauge consists of two resistance temperature detectors on the top and bottom faces of a thin ceramic substrate. The heat flux is calculated from temperature measurements of the two temperature detectors. An analytical model is used to simulate the gauge response. Several numerical methods to calculate the heat flux are investigated to improve the time response of the gauge. The error due to gauge intrusiveness and the validity of one-dimensional heat transfer within the gauge is studied by solving a steady state two-dimensional composite problem using a semi-analytical approach. Gauge fabrication techniques and measurement devices are discussed. Testing apparatus, including a "close-to-entry" condition apparatus using an arcjet at low pressure and a conduction calibration furnace, are explained. Experimental data showing qualitative gauge response is presented.
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Canhoto, Paulo. "Optimization of Heat Transfer Systems and Use of the Environmental Exergy Potential - Application to Compact Heat Exchangers and Heat Pumps." Doctoral thesis, IIFA - Instituto de Investigação e Formação Avançada, Universidade de Évora, 2012. http://hdl.handle.net/10174/7775.
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In this thesis, the optimization of forced convection heat sinks and groundwater-source heat pumps is addressed with the purpose of improving energy efficiency. Parallel ducts heat sinks are considered under constrained (fixed) pressure drop, pumping power and heat transfer rate. The intersection-of-asymptotes method is employed together with numerical simulations and relationships for determining optimum hydraulic diameter are put forward. An optimal design emerges under fixed heat transfer rate, which matches that found through the joint minimization of pressure drop and pumping power. With regard to heat pumps optimization, the relation between coefficient-of-performance and air-to-ground exergy potential is established, showing that energy saving as compared to air-to-air systems depends on the square root of that potential. The exergy potential in the Evora region is estimated, and exergy analysis of groundwater-source systems helps identifying distinct conditions of operation: maximum/null net exergy output and best trade-off between environmental exergy utilization and power input.
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Canhoto, Paulo Manuel Ferrão. "Optimization of heat transfer systems and use of the environmental energy potential: application to compact heat exchangers and heat pumps." Doctoral thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/14559.
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In this thesis, the optimization of forced convection heat sinks and groundwater-
-source heat pumps is addressed with the purpose of improving energy efficiency.
Parallel ducts heat sinks are considered under constrained (fixed) pressure drop,
pumping power and heat transfer rate. The intersection-of-asymptotes method is
employed together with numerical simulations and relationships for determining
optimum hydraulic diameter are put forward. An optimal design emerges under
fixed heat transfer rate, which matches that found through the joint minimization
of pressure drop and pumping power. With regard to heat pumps optimization,
the relation between coefficient-of-performance and air-to-ground exergy potential
is established, showing that energy saving as compared to air-to-air systems depends
on the square root of that potential. The exergy potential in the ´Evora region
is estimated, and exergy analysis of groundwater-source systems helps identifying
distinct conditions of operation: maximum/null net exergy output and best trade-off
between environmental exergy utilization and power input; RESUMO:Esta tese apresenta a optimiza¸c˜ao de dissipadores de calor e de bombas de calor
geot´ermicas para melhoramento da eficiˆencia energ´etica. S˜ao estudados dissipadores
de passagens paralelas sujeitos a constrangimentos de queda de press˜ao, potˆencia de
bombeamento e taxa de transferˆencia de calor. Utiliza-se o m´etodo da intersec¸c˜ao-
-das-assimptotas juntamente com simula¸c˜oes num´ericas, e apresentam-se express˜oes
do diˆametro hidr´aulico ´optimo. Um design ideal emerge no caso de transferˆencia
de calor fixa, o qual se aproxima da minimiza¸c˜ao conjunta de queda de press˜ao e
potˆencia de bombeamento. Relativamente `as bombas de calor, estabelece-se uma
rela¸c˜ao entre coeficiente-de-performance e potencial de exergia ar-solo, e mostra-se
que a redu¸c˜ao de consumo energ´etico comparado com sistemas ar-ar depende da raiz
quadrada desse potencial. O potencial de exergia em ´Evora ´e avaliado, e identificamse
v´arias condi¸c˜oes de funcionamento usando an´alise exerg´etica: m´axima/nula sa´ıda
l´ıquida de exergia e compromisso ´optimo entre utiliza¸c˜ao de exergia ambiental e
potˆencia fornecida.
4
MacKay, Robert Malcolm. "The Oregon Graduate Institute one dimensional time-dependent radiative convective model : theory and application /." Full text open access at:, 1990. http://content.ohsu.edu/u?/etd,202.
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McGurn, Sean J. T. "Application of heat transfer models to boiler fouling monitoring." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282256.
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Toal, B. R. H. "The application of heat pumps to low temperature drying." Thesis, University of Ulster, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378669.
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Oakes, Brian K. "Reduction of convective heat transfer from reacting flows by application of electric fields." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-08042009-040424/.
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Gupta, Jatin. "Application Of Conjugate Heat Transfer (Cht) Methodology For Computation Of Heat Transfer On A Turbine Blade." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1230064860.
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Okorafor, Agbai Azubuike. "A study of heat and mass transfer in a double-diffusive system /." Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: no access until May 13, 2009, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26048.
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MacIver, Alasdair. "The application of enhanced surfaces to boiling over tube bundles." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1472.
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Demir, Vedat. "Development and application of vacuum heat-treated silicon nitride ceramics." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310039.
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Nakamura, Chikara. "Asymptotic behaviors of random walks; application of heat kernel estimates." Kyoto University, 2018. http://hdl.handle.net/2433/232222.
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Payne, Russell. "The application of artificial neural networks to combustion and heat exchanger systems." Thesis, University of South Wales, 2005. https://pure.southwales.ac.uk/en/studentthesis/the-application-of-artificial-neural-networks-to-combustion-and-heat-exchanger-systems(684a7758-1b1c-4560-8df1-e482b42ef8a2).html.
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The operation of large industrial scale combustion systems, such as furnaces and boilers is increasingly dictated by emission legislation and requirements for improved efficiency. However, it can be exceedingly difficult and time consuming to gather the information required to improve original designs. Mathematical modelling techniques have led to the development of sophisticated furnace representations that are capable of representing combustion parameters. Whilst such data is ideal for design purposes, the current power of computing systems tends to generate simulation times that are too great to embed the models into online control strategies. The work presented in this thesis offers the possibility of replacing such mathematical models with suitably trained Artificial Neural Networks (ANNs) since they can compute the same outputs at a fraction of the model's speed, suggesting they could provide an ideal alternative in online control strategies. Furthermore, artificial neural networks have the ability to approximate and extrapolate making them extremely robust when encountering conditions not met previously. In addition to improving operational procedures, another approach to increasing furnace system efficiency is to minimise the waste heat energy produced during the combustion process. One very successful method involves the implementation of a heat exchanger system in the exiting gas flue stream, since this is predominantly the main source of heat loss. It can be exceptionally difficult to determine which heat exchanger is best suited for a particular application and it can prove an even more arduous task to control it effectively. Furthermore, there are many factors that alter the performance characteristics of a heat exchanger throughout the duration of its operational life, such as fouling or unexpected systematic faults. This thesis investigates the modelling of an experimental heat exchanger system via artificial neural networks with a view to aiding the design and selection process. Moreover, the work presented offers a means to control heat exchangers subject to varying operating conditions more effectively, thus promoting savings in both waste energy and time.
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Hu, Xiaowei. "A study of nozzle jet application to winter maintenance vehicles." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447630.
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Lee, Jung Chul. "Fabrication, characterization, and application of multifunctional." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22697.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2007.Committee Chair: King, William; Committee Member: Allen, Mark; Committee Member: Brand, Oliver; Committee Member: Glezer, Ari; Committee Member: Joshi, Yogendra.
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Lippa, Edoardo. "Application of Phase Change Materials for heat storage in water tanks." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20183/.
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I PCM (Phase Change Materials) mostrano un'elevata entalpia di fusione con la capacità, in un volume relativamente piccolo, di immagazzinare o rilasciare grandi quantità di energia come calore latente durante la fusione e la solidificazione. Inoltre, i PCM in pratica richiedono che le loro temperature di transizione di fase superiore e inferiore siano all'interno dell'intervallo di temperatura operativa per una data applicazione e posseggano un'elevata conducibilità termica per un efficiente trasferimento di calore con un comportamento di scambio di fase congruente per evitare la separazione irreversibile dei loro costituenti.
Durante lo sviluppo dei PCM, sono stati studiati molti gruppi diversi di materiali, tra cui composti inorganici (sale e idrati salini), composti organici come paraffine, acidi grassi e persino materiali polimerici come il PEG.
La relazione tra la struttura fondamentale e le proprietà di immagazzinamento dell'energia di questi PCM è stata esaminata negli anni per determinare i meccanismi di accumulazione/emissione di calore con riferimento alle loro caratteristiche finali di immagazzinamento dell'energia.
La tesi mira a studiare l'applicazione dei Phase Change Materials in un serbatoio d'acqua per aumentare la capacità di accumulo termico negli impianti di riscaldamento degli edifici. La possibilità di utilizzare l'acqua come acqua calda sanitaria è stata esclusa dallo studio, per cui si è ipotizzato di utilizzarla solo per il riscaldamento o il raffreddamento a pavimento.
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Vivas, David. "Heat Pump System using Waste Energy for a District Heating Application." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-630.
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Nowadays, reducing energy usage as well as reducing environmental impacts due to energy efficiency measurements is very common in the industrial sector. The objective of these measurements is to achieve better sustainable energy systems.
Sandvik Materials Technology (SMT) AB, one of the business areas of the enterprise Sandvik AB, is not an exception in that field.
The aim of this thesis project is to analyze how to use waste energy from the cooling of a steel plant for an internal district heating (DH) system within the industrial area of SMT AB located in Sandviken, Sweden. In order to reduce the energy use, the economic cost and the environmental impacts within the industrial area.
In order to achieve the aim has been studied the heat pump devices as the system to transfer the waste heat from the cooling of the steel plant to the DH system. Therefore, after the introduction to the project (part 1: Introduction) and the explanation of the aim
(part 2: Aim, methodology and delimitations), the basics of the heat pumps are studied and explained (part 3: Heat pumps theoretical study). After that, the knowledge acquired in part 3 is applied to define and calculate the heat pump system which fulfill the required
objectives achieving the greatest energy, economical and environmental impacts reductions (part 4: Heat pump practical study).
The achieved results show that there is a great opportunity to reduce the energy use within the industrial area (until 45300 MWh per year), the economical cost (until 2 millions euros per year) and the 2 CO emissions (until 2.3 millions of 2 CO kg per year1).
Therefore, the conclusion is that it must be taken into account to build the heat pump system and also that the effort of finding possible energy efficiency measurements within the industrial sector must be one priority for all the industrial companies, not only because the possible potential economical reductions, but also because of the potential environmental impacts reductions.
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Freeman, Grant Andrew. "Indirect solar-assisted heat pumps for application in the Canadian environment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22305.pdf.
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Smith, Andrew. "A preliminary investigation into the geothermal application of long heat pipes." Thesis, University of Canterbury. Chemical and Process Engineering, 1990. http://hdl.handle.net/10092/8791.
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It is thought that a two phase thermosyphon may be used to remove geothermal energy from a geothermal aquifer to supply energy at a rate of the order of 10 kW to a small scale user, such as a domestic dwelling.
In this project a two phase thermosyphon, approximately 8m long, was constructed and tested in order to examine design procedures and to find optimum operating conditions.
The thermosyphon consisted of a 0.6m long evaporator section of 35mm pipe, a 6.20m long, vacuum jacketed, adiabatic section of 35mm pipe and a 1.06m long condenser section. Heat was supplied to the evaporator through a steam jacket using saturated steam at 140°C and cooling water was supplied to the condenser. Two working fluids, water and hexane, were tested and a 60 mesh stainless steel wick was also used in the evaporator.
When using water the maximum performance of 8740 ± 700 W was obtained at a cooling water flowrate of 34.0 ml/s, without using a wick. This heated the cooling water to a temperature of 81°C. When using hexane the maximum performance obtained was 2150 ± 300 W at a cooling water flowrate of 7 ml/s, without using a wick. These results compare well with the predicted values found using a calculation procedure presented by Engineering Services Data Unit, Item No. 81038. The use of accurate operating conditions when predicting the thermosyphon performance was found to be essential. The use of a simple wick in the evaporator was found to hinder heat transfer.
The limiting factor is thought to be the occurrence of film boiling in the evaporator. This was not predicted by ESDU 81038. The prediction of limits to heat transfer was not accurate and more work is needed in this area.
The overall results are encouraging and show that it is possible to transfer heat at a rate of the order of 10 kW, using a temperature drop of around 50°C as is required in a domestic geothermal application.
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White, Peter. "On the application of artificial intelligence techniques to heat exchanger design." Thesis, University of Ulster, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281354.
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Namasivayam, Sothy. "The application of machine intelligence to the design of heat exchangers." Thesis, University of Ulster, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359663.
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Azevedo, Juliana Antunes. "Urban heat and energy demand : application of an urban meteorological network." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6961/.
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The urban heat island (UHI) effect is an inadvertent modification of climate which leads to increased temperatures in urban areas. This in turn increases localised demand for air conditioning and refrigeration which can be a significant drain on energy resources. At a time of increasing economic, political and environmental concerns with respect to energy policy, security, efficiency and climate change, there is a need to focus efforts to understand energy usage in cities for current and future climates. Using data from an Urban Meteorological Network (UMN) along with a critiqued degree days methodology, this thesis analyses the UHI and estimate current and future cooling demand in Birmingham-UK. From the results it was possible to identify that currently the main factor in energy consumption is income, however when isolating income influence through normalization process it is possible to identify the impact of the UHI. A significant finding was that the distribution of the surface UHI appears to be clearly linked to landuse, whereas for canopy UHI, advective processes appear to play an important role. Analysing Tair data available from the UMN the cooling demand for summer 2013 and future climate scenarios were calculated and demonstrated the importance of high resolution air temperature measurements in estimating electricity demand within urban areas.
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Hardy, M. J. "Integrated surface plasmon generator for application in heat assisted magnetic recording." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676510.
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Presented here is a novel design for a vertical cavity surface emitting laser for supplying heat to a recording medium in a magnetic recording drive, in an attempt to overcome the superparamagnetic limit. Included in the thesis is a discussion of the requirement for a system to focus energy beyond the diffraction limit and onto a recording platter. Plasmonics is introduced as a method to achieve this focusing and the structure to be used in this work is presented. Initial modelling of the structure for a theoretical efficiency and hence feasibility of the design is then conducted. Fabrication of the device is discussed in detail and preliminary characterisation of the device is undertaken.
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Tiari, Saeed. "EXPERIMENTAL AND NUMERICAL STUDY OF LATENT HEAT THERMAL ENERGY STORAGE SYSTEMS ASSISTED BY HEAT PIPES FOR CONCENTRATED SOLAR POWER APPLICATION." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/403481.
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Mechanical EngineeringPh.D.
A desirable feature of concentrated solar power (CSP) with integrated thermal energy storage (TES) unit is to provide electricity in a dispatchable manner during cloud transient and non-daylight hours. Latent heat thermal energy storage (LHTES) offers many advantages such as higher energy storage density, wider range of operating temperature and nearly isothermal heat transfer relative to sensible heat thermal energy storage (SHTES), which is the current standard for trough and tower CSP systems. Despite the advantages mentioned above, LHTES systems performance is often limited by low thermal conductivity of commonly used, low cost phase change materials (PCMs). Research and development of passive heat transfer devices, such as heat pipes (HPs) to enhance the heat transfer in the PCM has received considerable attention. Due to its high effective thermal conductivity, heat pipe can transport large amounts of heat with relatively small temperature difference. The objective of this research is to study the charging and discharging processes of heat pipe-assisted LHTES systems using computational fluid dynamics (CFD) and experimental testing to develop a method for more efficient energy storage system design. The results revealed that the heat pipe network configurations and the quantities of heat pipes integrated in a thermal energy storage system have a profound effect on the thermal response of the system. The optimal placement of heat pipes in the system can significantly enhance the thermal performance. It was also found that the inclusion of natural convection heat transfer in the CFD simulation of the system is necessary to have a realistic prediction of a latent heat thermal storage system performance. In addition, the effects of geometrical features and quantity of fins attached to the HPs have been studied.
Temple University--Theses
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Oster, Kamil. "Ionic liquid-based nanofluids for thermal application." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/ionic-liquid--based-nanofluids-for-thermal-application(1039c799-bc2b-49b3-ba1d-dab27f607a2e).html.
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Heat transfer fluids are materials responsible for heat distribution, transfer and storage. Their significance is undeniable - many technological processes cannot be carried out without using heat transfer materials (for example due to overheating). These are usually mixtures of many compounds, for example glycols, silicones or water. Today's technologies constantly require more efficient, environmentally- and economically-friendly solutions for heat transfer applications. It is necessary to know the full physicochemical characteristics to design a new heat transfer fluid (mainly density, heat capacity, viscosity and thermal conductivity). Nanofluids (mixture of a basefluid and nanoparticles) were proposed as a solution for many industrial issues due to their enhanced thermophysical properties (i.e. thermal conductivity) than pure liquids. Moreover, these enhancements exhibit unusual features which make this group of materials interesting from molecular and industrial point of view. Ionic liquids, task specific materials with tuneable properties were repeatedly recommended as heat transfer fluids due to their specific properties (mainly low vapour pressure, wide liquidus range, or non-flammability) caused by the ionic structure. A very interesting material can be obtained by mixing ionic liquids and nanoparticles where specific properties of ionic liquids are preserved, and thermophysical properties are enhanced due to nanoparticles dispersion. In this work, we investigated ionic liquid - based nanofluids from the experimental and theoretical point of view, including imidazolium-, pyrrolidinium- and phosphonium-based ionic liquids with several different anions, and multiwalled carbon nanotubes, graphite, boron nitride and mesoporous carbon as nanoparticles, and also in mixtures with water. As a final result, we assessed the molecular recognition of the thermophysical properties enhancements in ionanofluids, developed the predictive models for physical properties, compared all investigated systems to commercial heat transfer fluids. The project was supported by King Faisal University (Saudi Arabia) through a research fund from the International Cooperation and Knowledge Exchange Administration department at KFU. Cytec are thanked for the generous donation of the trihexyl(tetradecyl)phosphonium chloride sample.
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Elalem, Kaled. "Application of heat pipe technology in permanent mold casting of nonferrous alloys." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85067.
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The issue of mold cooling is one, which presents a foundry with a dilemma. On the one hand; the use of air for cooling is safe and practical, however, it is not very effective and high cost. On the other hand, water-cooling can be very effective but it raises serious concerns about safety, especially with a metal such as magnesium. An alternative option that is being developed at McGill University uses heat pipe technology to carry out the cooling.The experimental program consisted of designing a permanent mold to produce AZ91E magnesium alloy and A356 aluminum alloy castings with shrinkage defects. Heat pipes were then used to reduce these defects. The heat pipes used in this work are novel and are patent pending. They are referred to as McGill Heat Pipes.
Computer modeling was used extensively in designing the mold and the heat pipes. Final designs for the mold and the heat pipes were chosen based on the modeling results.
Laboratory tests of the heat pipe were performed before conducting the actual experimental plan. The laboratory testing results verified the excellent performance of the heat pipes as anticipated by the model.
An industrial mold made of H13 tool steel was constructed to cast nonferrous alloys. The heat pipes were installed and initial testing and actual industrial trials were conducted. This is the first time where a McGill heat pipe was used in an industrial permanent mold casting process for nonferrous alloys.
The effects of cooling using heat pipes on AZ91E and A356 were evaluated using computer modeling and experimental trials. Microstructural analyses were conducted to measure the secondary dendrite arm spacing, SDAS, and the grain size to evaluate the cooling effects on the castings. The modeling and the experimental results agreed quite well. The metallurgical differences between AZ91E and A356 were investigated using modeling and experimental results. Selected results from modeling, laboratory and industrial trials are presented. The results show a promising future for heat pipe technology in cooling permanent molds for the casting of nonferrous alloys.
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Wright, G. A. "Mathematical modelling of heat transfer processes with particular application to lighting fittings." Thesis, London South Bank University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373441.
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Ramadan, Mohamed Elamin Awad. "A novel high capacity space efficient heat storage system for domestic application." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53239/.
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Solar energy assisted heat pump (SAHP) and Direct Expansion Solar Assisted Heat Pump (DX-SAHP) systems are among the promising means of reducing the consumption of fossil fuels for heat production in residential building applications. The research in this thesis introduces a novel system that integrates solar energy, THS storage, and DX-SAHP. The objective is to develop an efficient heating system for existing homes in the cold climatic region which is sustainable and acts as an alternative to the conventional high energy loss domestic water and space heating systems. One of the prospective techniques of producing and storing of thermal energy is the application of thermochemical materials. Storage of heat in salt hydrates provides an efficient and compact way of storing energy. Hence, the properties of salt hydrates that determine the storage capacity are being investigated. An experimental test has undertaken to assess the effect of integrating the new design of thermochemical storage materials with a solar-assisted multifunctional heat pump system. This research presents a novel design that involves the integration of DX-SAMHP and a hot water tank with a thermochemical sorption jacket. Investigations have been carried out to determine a suitable temperature range for household heating systems. Expanded Vermiculite (host matrix) and CaCl2 (hygroscopic salt) have been used as composite material in an adsorbent reaction jacket for a domestic water tank. The new design has a total volume of 20 kg of V/CaCl2, which can store the thermal energy with a complete reaction. The results show the high capability of the tested materials to enhance the domestic heating system performance when applied in cold regions. The feasibility of the designed system for residential space and water heating is also demonstrated. The maximum energy density obtained through the discharging process is 565 kJ/kg. It is also revealed that the coupling of thermochemical heat storage and heat pump increases the thermal production capacity by 1.166 kWh during the discharging process.
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Hamze, Samah. "Graphene based nanofluids : development, characterization and application for heat and energy systems." Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S010.
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Dans notre vie quotidienne, le transfert de la chaleur et de l’énergie constitue la base de nombreux processus industriels. L’épuisement progressif des énergies fossiles conduit à améliorer et optimiser les rendements de ces échanges par de nouveaux procédés. Pour cela, une idée d’améliorer la performance thermique des fluides dans les échangeurs de chaleur a été proposée pour réduire l’énergie consommée pour l’échange de chaleur. Cette idée est basée sur l’introduction des nanoparticules solides qui présentent des propriétés thermiques beaucoup plus importantes que les liquides caloporteurs dans ces derniers, en obtenant un nanofluide. Cette introduction a pour effet d’augmenter la conductivité thermique du fluide mais d’autre part provoque une augmentation défavorable de sa viscosité qui résulte en une augmentation de la puissance de pompage. Alors il faut faire un compromis entre la stabilité, la conductivité thermique et la viscosité des nanofluides. Dans cette étude, des nanofluides à base de graphène à quelques couches et un fluide commercial, Tyfocor® LS, ont été préparés dans la gamme de concentration massique 0,05-0,5% en utilisant trois surfactants différents. Une étude complète sur ces nanofluides est présentée, y compris la synthèse des feuillets de graphène, la préparation des nanofluides et l’étude de leur stabilité, ainsi que l’évaluation expérimentale de leurs propriétés thermophysiques en fonction de la concentration en graphène, du type de surfactant utilisé et de la température dans la gamme 283,15-323,15 K. Finalement, sur la base de ces résultats et par une approche qualitative, le potentiel applicatif des nanofluides dans des systèmes énergétiques est déterminé pour sélectionner le meilleur candidat. Les résultats ont montré une bonne amélioration de la performance thermique par rapport aux fluides de base dans la gamme de température testée et surtout le nanofluide de la série du surfactant Pluronic® P-123 de concentration massique 0,25%In our daily lives, the heat and energy transfer forms the basis of many industrial processes. The gradual depletion of fossil fuels leads to improving and optimizing the efficiency of these exchanges through new processes. To this end, the idea of improving the thermal performance of fluids in heat exchangers has been proposed forward to reduce the energy consumed for heat exchange. This idea is based on the introduction of solid nanoparticles, which have much greater thermal properties than heat-transfer fluids in the latter, obtaining a nanofluid. This introduction has the effect of increasing the thermal conductivity of the fluid but on the other hand causes an unfavorable increase in its viscosity, which results in an increase in pumping power. So a compromise has to be made between the stability, thermal conductivity and viscosity of nanofluids. In this study, few layer graphene based nanofluids and a commercial fluid, Tyfocor® LS, were prepared in the weight concentration range 0.05-0.5% using three different surfactants. A complete study on these nanofluids is presented, including the synthesis of the graphene sheets, the preparation of the nanofluids and the study of their stability, as well as the experimental evaluation of their thermo-physical properties as a function of the graphene concentration, the type of surfactant used and the temperature in the range 283.15-323.15 K. Finally, on the basis of these results and through a qualitative approach, the potential application of nanofluids in energy systems is determined in order to select the best candidate. The results showed a good improvement of the thermal performance compared to the base fluids in the tested temperature range and especially the nanofluid of the Pluronic® P-123 surfactant series with a mass concentration of 0.25%
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Moore, Travis J. "Application of Variation of Parameters to Solve Nonlinear Multimode Heat Transfer Problems." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4254.
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The objective of this work is to apply the method of variation of parameters to various direct and inverse nonlinear, multimode heat transfer problems. An overview of the general method of variation of parameters is presented and applied to a simple example problem. The method is then used to obtain solutions to three specific extended surface heat transfer problems: 1. a radiating annular fin, 2. convective and radiative exchange between the surface of a continuously moving strip and its surroundings, and 3. convection from a fin with temperature-dependent thermal conductivity and variable cross-sectional area. The results for each of these examples are compared to those obtained using other analytical and numerical methods. The method of variation of parameters is also applied to the more complex problem of combined conduction-radiation in a one-dimensional, planar, absorbing, emitting, non-gray medium with non-gray opaque boundaries. Unlike previous solutions to this problem, the solution presented here is exact. The model is verified by comparing the temperature profiles calculated from this work to those found using numerical methods for both gray and non-gray cases. The combined conduction-radiation model is then applied to determine the temperature profile in a ceramic thermal barrier coating designed to protect super alloy turbine blades from large and extended heat loads. Inverse methods are implemented in the development of a non-contact method of measuring the properties and temperatures within the thermal barrier coating. Numerical experiments are performed to assess the effectiveness of this measurement technique. The combined conduction-radiation model is also applied to determine the temperature profile along the fiber of an optical fiber thermometer. An optical fiber thermometer consists of an optical fiber whose sensing tip is coated with an opaque material which emits radiative energy along the fiber to a detector. Inverse methods are used to infer the tip temperature from spectral measurements made by the detector. Numerical experiments are conducted to assess the effectiveness of these methods. Experimental processes are presented in which a coating is applied to the end of an optical fiber and connected to an FTIR spectrometer. The system is calibrated and the inverse analysis is used to infer the tip temperature in various heat sources.
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Hilpert, Benjamin. "Application of Industrial Ecology Concepts in Solar Energy Heat Systems in Mexico." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-256554.
Full textAbstract:
The increased understanding of the growing environmental harm linked to today's throughput industry reaches politics and the general public more and more. This study objects to increase resource use of materials and reduce the associated environmental impact. It is being conducted in the solar energy sector of the middle-income country, Mexico, on the basis of an underlying sample company. The chosen concept to achieve this goal is with Industrial Ecology, which combines several other approaches like an umbrella, far-reaching and represents an alternative to counteract the problems today´s and future generations are facing. Application-based approaches like Circular Economy, Waste Management, Loop Closing, and Industrial Symbiosis are taken into consideration to reduce the use of virgin materials and lessen the environmental impact of industrial activities in the middle-income country Mexico. Existing definitions and provided possibilities of Industrial Ecology and its included approaches were studied to set the base of the investigations together with a literature review of the manufacturing and the importance of small and medium-sized companies in Mexico. Primary data collection regarding company-specific information and their procedures were carried out as follows; after the preparation of the plans and schemes for the different areas of the company's value chain, the internal processes, the material flow, as well as the transportation were examined in more detail. Together with interviews of the company's managers, plans were verified and potentials for improvement towards sustainable development were identified. Using the previously acquired information of the considered approaches of IE, development opportunities in all areas of the value chain as well as the external collaboration possibilities could now be developed. The results show that the emissions of the example company mainly arise in the production of hot water storage tanks and solar collector frames, The implementation of the measures could also lead to more efficient use of materials, improved use of infrastructure, and reveals great potential of improvements in particular in industrial symbiosis. There are various opportunities to achieve environmental goals through new collaboration and networking. Improvements in the use of available materials, the recycling policy, as well as the transport of products and residues to and from the installation site could be achieved for the sample company. By demonstrating external cooperation opportunities such as transport or service sharing and their benefits to the participating companies, it has been shown that it would be possible to create an innovative and sustainable competitive advantage and to positively influence the financing pattern even for middle-income countries. The outcomes of the study show that with IE and the associated application-based approaches it is also practically possible to achieve further development of companies towards sustainable production and development. The implementation of the concepts of IE known from literature is generally more complicated in practice than it is described in theory. Also, because literature just give a rough picture of how such systems should look like but they do not provide any specific details. Nevertheless, it has been shown that it is also feasible in the case of middle-income countries to establish and organize themselves sustainably as a company for the future. In addition to the internal optimization measures of the business, also the exploration of the external possibilities of Industrial Symbiosis and collaboration are recommended.Det största problemet på jorden idag är att naturresurserna är ändliga och att det bara finns en atmosfär att bo i. Vi måste hantera produktionen och utsläppen varsamt för att få en hållbar värld. Industriell ekologi (IE) är ett holistiskt koncept för att designa om industriella aktiviteter. Det är baserat på antagandet att miljöpåverkan från mänskliga aktiviteter måste minskas. Konceptet beskriver en möjlig lösning för dagens industriella och sociala dödläge genom att använda naturliga ekosystem som förebild. Den växande förståelsen för den stegrande miljöpåverkan som är associerad med moderna materialflöden från industrin har nått politiken och den allmänna massan med ökad hastighet. Dessutom har Cirkulär Ekonomi uppmärksammats mer under senaste tiden för att minska industriella miljöproblem. Även om litteraturen är i ett tidigt stadium verkar IE erbjuda värdefulla insikter som förenar användbara miljöaspekter. Det finns begränsat med studier om IE i industrin, speciellt när det kommer till ett medelinkomstland som Mexiko. Detta arbete fokuserar på tillämpningen av IE-koncept med tillhörande aspekter för att minimera miljöpåverkan från industriella aktiviteter och minska användningen av jungfruliga material. Det resulterar i hållbar utveckling för ett exempelföretag som undersöks, skapande av samarbeten för industriell symbios (IS) och ett hänsynstagande för hållbart företagande (BM). The valda aspekterna är först introducerade för att visa dess generella potential. Sedan för att skapa en grund, introduceras signifikansen av små och medelstora företag (‘pequeña y mediana empresa’ - PyMEs) i Mexiko, fördelar i konkurrenskraft genom IE och miljöpåverkan från sådana fabriker. Dessa steg är utförda i en litteraturstudie. I nästa del inhämtas företagets specifika data för deras processer och miljö genom semi-strukturerade intervjuer och rundturer i driften. Genom att använda information av utvecklingspotential i alla steg av värdekedjan kan nu externa samarbetsmöjligheter. Dessutom är genomförbarheten för åtgärder hos liknande företag granskade. Till sist föreslår studien framtida lösningar för exempelföretaget för att skapa fler hållbara industriella aktiviteter och för att stödja ytterligare IE-användning inom industrin.
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Awino, Hellen Rose Anyango. "Design-integrated Urban Heat Island analysis tool and workflow : development and application." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123577.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Architecture, 2019"June 2019." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 106-108).
The Urban Heat Island (UHI) effect is a well-studied phenomenon broadly attributed to human activities that transform open terrain into cityscapes. Among global 21st-century concerns, projected trends in population growth, urbanization, and regional climate change could exacerbate the warming in cities and intensify the UHI effect. Yet, microclimate analysis essential to assessing UHI intensity is often neglected, resulting in poor planning practices with adverse effects on health, comfort and energy use within cities. With buildings responsible for substantial quantities of global energy consumption and carbon emissions, this context demands climate-responsive design to achieve better-performing cities. The UHI effect presents an urban design challenge, but only recently has there been a platform for design workflow integration.
Despite existing engines that accurately evaluate UHI intensity in urban environments, architects, designers, and urban planners have often not incorporated such simulation into microclimate studies due to prohibitively expensive computational costs, disconnected workflows within unintuitive or unfamiliar platforms, and uncertainty about difficult-to-obtain urban climatology parameters. These hindrances cause impactful delay within the design feedback loop and often generate a lack of confidence in the simulation process and output. This thesis proposes a Computer-Aided-Design integrated graphical user interface for the Urban Weather Generator (UWG), an urban-scale climate prediction tool developed by Bruno Bueno to simulate microclimatic conditions of urban sites using operational weather station data.
The goal is to make the powerful and computationally cheap engine accessible to design workflows by incorporating it as a plugin within the conventional design software Rhinoceros-3D, and by coupling it with the Local Climate Zone classification scheme developed by urban climate experts lain Stewart and Timothy Oke to standardize quantitative physical descriptions of cities. The proposed update automates geometric parameter extraction and implements a reliable means of urban morphological parameter estimation. As a case study, an iterative urban-scale design exploration is analyzed for selected climates.
by Hellen Rose Anyango Awino.
S.M.
S.M. Massachusetts Institute of Technology, Department of Architecture
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Sun, Wei-Chih, and 孫偉智. "Application of the Chaotic Convection Heat Transfer in the Heat Exchangers." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/20418635235547487484.
Full textAbstract:
碩士國立屏東科技大學
機械工程系
93
The phenomenon of secondary flow can be created by the curved pipe and it can obtain a better heat transfer than in a straight tube. Therefore a suitable curved tube can mix the flow better chaotically. The purpose of this study was to analyze the property of a carevd tube, which creates chaotic, mixing and the properties of a regular helical tubes. The two types of tube (shell and tube, and tube-in-tube) were used in the heat exchanger system to analyze properties of heat transfer. The results were found the chaotic mixing created the so-called chaotic tube which can increase heat transfer rate and well mixed temperature on flow. The shell and tube heat exchanger system had a higher total heat transfer rate, but the flow pressure were also increased relatively. The selection of the way for the working fluid was very important. The counter flow could achieve higher heat transfer efficiency in shell and tube helical tube than that of in chaotic tube. The temperature was more stable and well mixed in counter flow, and the thermal stress concentration was hardly found in the heat exchanger system. Thus, counter flow can reduce the probability that the tube is broken by thermal stress concentration.
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Guo, Mei-zuo, and 郭美佐. "EHD technology in the centralized heat source of heat dissipation application." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/94541146552738061407.
Full textAbstract:
碩士國立雲林科技大學
機械工程系碩士班
100
LED (Light Emitting Diode, LED) is made of semiconductor material for the light emitting devices. It has the advantage of saves the electricity、environmental protection、small size、quick to response. However, the LED luminous input power only has about 20 to 30 % becomes light, the other energy (70 to 80%) turn into heat loss to environment, leading to increase junction temperature ,loss of life and reduce luminous intensity. The traditional cooling technology use heat sink to increase the contact area for improving heat dissipation, but it can not apply to the small installing space for LED cooling.This study utilized an embedded EHD structure upon ceramic package to augment the heat transfer performance of the whole heat sink module. The proposed EHD electrode can generate ionic wind to turn the major heat transfer mechanism from natural convection into force convection, leading to a significant rise of heat dissipation. In addition, the much lower weight of the present EHD device can substantially reduce the weight of the LED thermal module, and becomes more flexible in practical thermal design. The experimental results show that the size of the electrode angle, different shape of the ground, the distance between the electrode altitude and the electrode and the grounding of the ion wind has considerable influence. Electrode altitude of influence is more obvious when the electrode altitude and ground distance in a limited range of ion wind to achieve better results.
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Huang, Wen-Wei, and 黃文維. "Benefit Discussion of Heat Energy and Energy-Conservation Application of Heat Pump." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/58230179371655375057.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
103
The living surroundings of human being are threatened unprecedentedly due to the poor climate and environment in the recent years gradually. As a result, the awareness of environment protection makes the consciousness of energy efficiency and carbon reduction concerned. However, energy-saving is still the profitable method in the mainstream before the alternative energy technology will be universalized in our daily life. Gradually speaking, water heater can be divided into five systems, including fuel heater, gas water heater, solar water heater, electric water heater, and heat pump. There are some reasons explain why high electricity conversion efficiency of the heat pump becomes the mainly substitute program. First is thermal converting efficiency of fuel heater and gas water heater is low but fuel fee is high. Second is electric water heater can divert electricity into heat directly but the efficiency is limited. Final is solar energy water heater is depended on the sunshine hours and it might be an unstable system as well. From those weaknesses of the different systems, we can understand high electricity conversion efficiency of the heat pump is an important substitute program. Consequently, heat pump heater system inspires our motivation to study and analyses more detail about it. We want to compare its merit and shortcoming with others, analyses energy efficiency and carbon reduction, improve the efficiency of actual business work and reach the cost recovery. The author has cooperated with energy service. Based on the efficiency of heat pump system, this thesis will focus on the measurement of energy conservation benefit of heater pumper system to investigate the source of energy that existing heaters system used and its efficiency. He also made an effort on how to spread the energy-saving to business work and common household widespread. Furthermore, he even used air-conditioner to make the heat pump water system implied in more space. With the policy of energy-saving in Taiwan, we hope businessmen and citizens can take good use of government’s help and source to establish the concept about energy-saving and do it spontaneously.
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Lu, Chun-Hsien, and 呂俊賢. "Application of Plant Heat Shock Protein, HSP101." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/u4wu29.
Full textAbstract:
碩士國立成功大學
生物科技研究所碩博士班
92
Among heat-shock proteins, hsp101 appears to play a major and specific role in acquired thermotolerance of plant. The function of HSP101 is to promote the resolubilization of protein aggregates, and reactivate protein activity in cooperation with other molecular chaperones as a refolding machine under heat stress. Therefore, HSP101 is essential for plant survival under severe heat stress. We had transformed tobacco with rice hsp101 gene through Agrobacterium-mediated transformation. Stable integration and expression of the transgene into tobacco genome was demonstrated by PCR, Southern and western blot analyses. We found that transgenic plants with overexpressing rice HSP101 confer thermotolerant ability. The selection markers currently used for plant transformation have raised some concerns such as environmental safety, antibiotic resistance and food allergenicity. To take advantage of the function of HSP101, we are trying to develop hsp101 gene as a selection marker, with high temperature as the selection pressure during the process of plant transformation. We demonstrated that transformants could be obtained by this novel selection method after Agrobacterium-mediated transformation. Our preliminary results show that transformants selected with high temperature expressing higher GUS level than traditional kanamycin selection method. We expect that transgenic plants selected through this method will confer thermotolerant ability.
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Cheng, Chao-Chi, and 鄭兆岐. "Heat Dissipation Performance of Heat Pipe for The Application of Light Emitting Diode." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/98903227399612587705.
Full textAbstract:
碩士國立中興大學
精密工程學系所
96
The purpose of this study was to discuss the heat dissipation methods for light emitting diode. There are two major parts in the study: (1) Improving LED packaging materials. The behavior of having low thermal resistance and high thermal diffusion efficiency are evaluated by coating a copper material on LED base layer. We calculate the heat transfer simulation using 3-D finite element method. The simulation results of various packaging area parameters were presented. (2) To design heat pipe structures as heat sink for a interior LED illuminator set. The experiments were conducted to investigate the cooling characteristics of heat pipes by changing working fluid mass and working angle. Additionally, both discrete hotspot of LED and central heating of heat pipe were studied. From the first simulation result, it was found that the addition of 9cm2 copper-packaged area improves the thermal dissipation of LED, resulting in a reduction of chip temperature lower 5℃ than non-packaging pattern. Secondly, the results of heat pipe experiments show that when the experimental sets of LED illuminator of LED was used in horizontal angles, resulting in the heat pipe which fill 2.52g water volume have the best thermal properties than others. Resulting in the heat source temperature maintain in 50℃. Whereas other have higher temperature results due to the steam inside pipe choked. Next, when the LED illuminator sets was used in inclined angles, the heat pipe which fill 7.56g water volume have the best thermal properties than others. The heat source temperature can reach 60℃. All of the experiments were performed and the results were presented. The experiments results show in this study can therefore be used for the application of heat dissipation for LED.
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Liao, Wan-Rong, and 廖婉蓉. "Application of Vortex Generators to Heat Transfer Enhancement of Pin-Fin Heat Sinks." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/21215317109709939448.
Full textAbstract:
碩士華梵大學
機電工程學系
102
In this thesis, the thermal-fluid characteristics of a pin-fin heat sink with vortex generators that modify the flow field and enhance the heat transfer in a cross flow are investigated. The effects of the Reynolds number of the flow, the attack angle of the vortex generators, the shortest distance between the vortex generators, the distance between each vortex generator and the heat sink, the height of the vortex generators, and the configuration of the vortex generators on the heat transfer enhancement of the pin-fin heat sink are investigated by infrared thermography. The results show that the thermal resistance decreases as the Reynolds number increases, but that decrease tends to diminish with increasing Reynolds number. By considering the thermal resistance and the pressure difference, the attack angle of 30o is a better arrangement of the vortex generators. The thermal performance is favorable when the shortest distance between the vortex generators equals the length of the heat sink. The thermal resistance increases as the shortest distance between the vortex generators is smaller than the length of the heat sink, while the pressure difference increases as the shortest distance between the vortex generators is larger than the length of the heat sink. The heat transfer of the heat sink is higher when the vortex generators are installed at the middle of the heat sink. Although increasing the vortex generator height can enhance the heat transfer, the pressure difference also increases. A lower thermal resistance and pressure difference are achieved using the common-flow-up configuration of the vortex generators than are achieved using the common-flow-down configuration.
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YI, Wen-Yuan, and 易文元. "Application and Analysis of DLC Film Heat Transfer." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/95335542167098287799.
Full textAbstract:
碩士聖約翰科技大學
自動化及機電整合研究所
97
The purpose of this research is to demonstrate the widespread application of Diamond-Like Carbon (DLC) membrane as an outstanding protective coating in cooling electronic devices, from design and testing perspectives. By applying DLC membrane on the surface of video cards cooling fins, the study has further to realize the cooling effects of DLC. The aim of this experimental work is to plate the aluminum heat sinks with various thickness range of DLC membrane (before sealing) to analyze its cooling effect at different stage. Having the nature of high heat conduction, DLC could significantly raising the heat transfer from GPU and video memory chips to the cooling fins than expected, providing unbeatable cooling effect which further sustain the efficiency & performance of graphic cards and extent service life of the graphic cards in general. Diamond-Like Carbon (DLC) membrane, from thickness, is categorized from 0.9μm, 1.6μm, 2.3μm, 3μm to 3.7μm respectively. Each specified measurements are taken into cross-analysis in comparing with those DLC membrane which is not plated on aluminum. The result of this experiment shows that the temperature is reduced by 5℃on the cooling radiator with aluminum-plated DLC membrane when comparing with non-plated DLC membrane. Furthermore, the value of thermal resistance also reduces about 26% on aluminum-plated DLC membrane. The thinner the DLC membrane is, the possible the thickness configuration is uneven which causes the value of thermal resistance in comparatively inconstant at the low heating watt. With tests, when the higher watt is induced, the DLC membrane will thus performs in reducing thermal resistance. By comparing the temperature of cooling fins in matching with differential thickness of DLC membrane, research shows that 3.7μm reveals the lower temperature than others. Nevertheless, the test data also demonstrates that the heat source temperature in various thickness of DLC membrane may not have very much disparity, roughly 0.9℃.
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Chen, Bo-Ren, and 陳柏任. "Application of Heat Pipe in Energy Storage System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/06187418235464646939.
Full textAbstract:
博士國立臺灣大學
機械工程學研究所
95
This dissertation experimentally and theoretically investigates the thermal performances of three innovative energy storage system designs which are subcooled ice storage air-conditioning system, two-phase thermosyphon solar water heater and phase change material (PCM) cooling module. Theoretical models are developed to simulate the thermal characteristics of the systems with various design modifications by employing thermal resistance-capacitor model (RC model) in this research. The subcooled ice storage air-conditioning system adopts an ice storage tank as a subcooler which utilizes the superior heat transfer characteristics of two-phase closed thermosyphon (with R-22 as working fluid) and eliminates the drawbacks found in conventional systems. The subcooler is effective to enhance 28 % more cooling capacity and 8% higher coefficient of performance (COP) by the subcooling process. The theoretical analysis result shows that the ice storage tank reduces 25 % of charging time by both increasing film condensation area in the fin tubes and heat transfer area between the fin tubes and energy storage material (water). The proposed two-phase thermosyphon solar water heater absorbs and transfers thermal energy by conducting boiling and condensation mechanisms with working fluid of ethyl alcohol inside. The system thermal efficiencies are experimentally verified from the hourly, daily, and long-term test. The two-phase thermosyphon can effectively reduce heat loss and provide 18 % higher system characteristic efficiency than that of the conventional systems. The simulation results show that the system achieves 3 % and 4 % greater charge efficiency as fin tubes number becomes twice and thermal conductivity of working fluid is 50 % higher, respectively. Six percent enhancement is obtained when wick structure are installed in the thermosyphon within lower working fluid fill ratio. The PCM cooling module applies energy storage concept in the system design. The device can shift peak heating power of the electronic component by storing or releasing the thermal energy. The performance testing results demonstrates that the cooling module lessens 46 % of the fan power consumption with PCM (tricosane) rather than water as energy storage material in the storage tank. The RC model analysis is performed to simulate the heater temperature variation for the case of oscillating heating power. The thermal performance can be enhanced with a larger fin area, higher PCM thermal conductivity, or increase of the area between the PCM and heat pipe. The maximum heater temperature decreases from 67.7 oC to 52.7 oC as the PCM thermal conductivity is treble.
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Chiu, Chao-Jen, and 邱昭仁. "Application of Observer in Inverse Heat Conduction Problem." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/82395499183229778520.
Full textAbstract:
碩士華梵大學
機電工程研究所
87
In many engineering problems, such as space shuttles、boilers、combustion chambers、rapid thermal processing for the wafer…etc., the heat flux and temperature can not be measured by sensors installed at high temperature locations usually, while these informations are very important in the analysis and design of the systems. Therefore, the sensors must be located at lower temperature location. The physical quantities such as heat flux, temperature, thermal conductivity, and thermal diffusivity at the high temperature locations are estimated by the inverse analysis from the measured temperature data. Then, the purpose of real time control can be fullfilled. In order to achieve the requirement of real time control, the theory of the observer is adopted as a basis. It is expected that the heat flux and temperature of the heated surface can be estimated simultaneously right after the measured temperature data have been taken. The advantages of the method are its ability of real time analysis, filtering measurement noise, and simpilicit. In this thesis, the application of the observer in the inverse heat conduction problem is testified. The optimal correction factors are found out.
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Yue, Hao-Rong, and 岳昊嶸. "Application of waste heat recovery of thermal energy." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/86086193916411087187.
Full textAbstract:
碩士元智大學
機械工程學系
99
In this thesis, the heat and the temperature difference between chip development, and create new energy-saving low-noise generation system. Use of two different metals within the chip temperature synthesis routes, if the temperature difference between the two contacts to potential difference, the release into the electronic transfer of electricity, business practices provide general liquidity and camping survival lighting charge to use. The hot water temperature control part of the generation used for clean, dirty beam target Tat to zero. This system is common life of the system and the industrial production of liquid inside the heat source, power generation, no noise, strong motor, no maintenance, easy to obtain heat, the system is light weight, as long as there is a fire place can be used. In this study, a practical way will be measured by the current size of the chip temperature series calculated the number needed to facilitate the future use to apply different design, such as Gua furnace, fuel cell heat pipe ... and so on.
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Liang, Nai-Wen, and 梁乃文. "Theoretical analysis and Application of Borehole Heat Exchangers." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/58388821904525503859.
Full textAbstract:
博士國立臺灣大學
機械工程學研究所
99
The aim of this study is to explore the theoretical analysis and application of Borehole Heat Exchangers (BHE). The U-shaped Borehole Heat Exchangers (UBHE) is usually used for the main subject of research of BHE. There, this study also uses the UBHE as its main research subject. The four major parts of the theoretical analysis are: determination of UBHE heat transfer analysis model, calculation of temperature distribution and outlet temperature of UBHE, using the mapping method and the shape factor method to calculate thermal resistance of UBHE, dimensionless UBHE heat transfer analysis. In this study, the applications of UBHE include installation of adiabatic plate and design of eight-branch-pipes UBHE. In addition, this research paper also compares the results with practical experimental data for verification, and further discusses the influences from related variables on outlet temperature of UBHE, so that can understand the general design criteria of UBHE. Moreover, this study investigated the influence variables of heat backflow for the optimal heat transfer performance of UBHE. In this study, the heat transfer analysis includes measurements of both outside and inside of the borehole. Outside the borehole, the finite line-source theory is applied to calculate wall temperature of the borehole in the steady and unsteady state. Inside the borehole, the quasi-three-dimensional theory is applied to evaluate temperature distribution of the working fluid. The research results show that mapping method were more accurate than Hellstorm G. method in the case of heat dissipation. Furthermore, compare calculated results with four cases of experimental data, and the accuracy range is within 3.1% for single UBHE. The study proposes a new thermal resistances calculation method to solve the heat transfer of UBHE. In this study, the effect of adiabatic plate in the middle of borehole was also considered. The major purpose of adiabatic plate was to prevent heat backflow which would cause raised of outlet temperature of UBHE and decrease the heat dissipation rate. The heat backflow would occur when the distance between two branch pipes (2D) was shorter and the depth of well (H) was deeper, and when the flow rate (Q) of working fluid was lower. For the condition of serious heat backflow, adiabatic plate can be added in the middle of borehole to increase the heat transfer rate. However, if the heat backflow is not so much, the adiabatic plate will block the heat transfer from one to the other side of borehole and result in temperature raise in outlet of UBHE. Hence, the increasing of D value is more efficient to raise the heat transfer of UBHE than using the adiabatic plate. This study takes one step further to investigate heat transfer of 8-branch-pipes BHE. Our theoretical analysis showed that, the energy efficiency of 8-branch-pipes BHE raised from 23.5% (low total flow rate) to 44.7 % (high total flow rate) when comparing with the single U-tube in the same total flow rate; and the total heat transfer rate of 8-branch-pipes BHE raised from 23.63 % (low total flow rate) to 42.18% (high total flow rate). Hence the 8-branch-pipes BHE proved to be a good design for increasing heat transfer rate of UBHE. Similarly, for the design of 8-branch-pipes BHE, it should try to avoid the occurrence of heat backflow. When the depth of well is deeper, the distance of downward branch pipe and central upward branch pipe is smaller, and the flow rate is lower, the effect of heat backflow will become more obvious. In this condition, the use of central upward branch pipe coated with adiabatic material will increase the heat transfer rate.
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HSU, CHIA-PIN, and 許家賓. "Application of Taguchi Method to Heat Pipe Performance." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4nk633.
Full textAbstract:
碩士中原大學
機械工程研究所
107
As technology continues to advance, product production process improvement, computing speed and efficiency of the wafer increases, product cooling issues are also more important, how to quickly transfer the waste heat of the wafer to other places for heat dissipation is a very important research topic. Heat pipes are used in the heat dissipation of electronic products for many years, especially the heat dissipation of notebook computers, how to use the heat dissipation performance in a limited space, rapidly transfer the heat generated by electronic components in a short period of time, reduce the operating temperature of electronic components, improve component stability. A thermocouple is used to measure the temperature of each component and calculate the thermal resistance during the experiment, determine the merits of heat dissipation performance based on the thermal resistance. The experimental wattage is controlled by 15W, 30W and 45W respectively, study heat dissipation performance under different heat conditions. This paper uses the Taguchi method to discuss the heat pipe module, by changing the type of heat pipe, number of bends, bending angle and other parameters, analyze and compare via thermal resistance data, analyze the effect on the thermal efficiency of heat pipe, find out the best combination of parameters. In this paper, ANOVA is used to investigate the control factors of the type of heat pipe, the number of bends and the bending angle on the quality.
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Lee, Ming-Yen, and 李明彥. "The application of field synergy theory on heat exchanger." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/ckua92.
Full textAbstract:
碩士國立高雄應用科技大學
機械與精密工程研究所
103
This purpose of this research is study the application of field synergy theory of heat transfer performance on heat exchanger (concentric tubes form). CFD analysis is applied to determine the distribution of the overall convective heat transfer coefficient 、entrance temperature、flow field、flow inlet velocity and different angle of impact on the field of synergy. The results of the analysis is showed that under the same boundary conditions, the reverse flow heat exchanger of the field synergy angle is less than the forward flow of heat, so heat the heat transfer efficiency is more excellent than the reverse flow of heat to flow along the exchanger. Finally, a Taguchi method is applied to optimize the field synergy angle with respect to the heat exchanger for a typical set of operating conditions. The results provide good guidance for the design of practical heat exchangers.
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Chiang, Jaw-Yeong, and 江照勇. "Application of Grey Prediction to Inverse Heat Transfer Problems." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/66221404697119960269.
Full textAbstract:
博士國立成功大學
機械工程學系碩博士班
96
This article applies Grey Prediction Method of Grey System Theory to improve the problem of errors in inverse operation due to the error of temperature measurement when analyze Inverse Heat Transfer Problems (IHTP) with Reversed Matrix Method. For IHTP, this research adopted Revered Matrix Method with Linear Least-squares Error Method to construct a linear inverse model. With finite difference method, we discretized governing equation that is designed to solve IHTP to construct a linear matrix equation. Through the re-arrangement of matrix equation, the unknown conditions (such as initial conditions, boundary conditions, thermal property or geometrical shape) could be demonstrated clearly and independently. Then substitute a small amount of successive measuring points temperature into the linear inverse model and solve the problems by Linear Least-squares Error Method. The process of inverse operation only need to measure a small amount points temperature to estimate the solution of IHTP, but in practical measurement of temperature, the errors of measurement of temperature are inevitable. Such errors will affect the accuracy of estimation value of inverse operation or even lead to an erroneous results. One of improvement method is to increase the number of temperature measurement points. Certainly, more accurate results of inverse operation we want to obtain, the number of measurement points we should increase. Therefore, this research uses the Grey Prediction Method to improve the defect with a hope that significant reduction of the number of practical temperature measurement points could also obtain the same accurate results of inverse operation. The small amount of direct temperature measurement points can increase to more amount of temperature points by Grey Prediction Method, and the temperatures of those increased points could still keep the correlations with previous temperatures from direct measurement. The increased number of temperature points could replace the number of temperature points that is necessary to increase for inverse operation. In other words, Grey Prediction Method could significantly reduce the number of practical temperature measurement points while keep the same accuracy as the results of inverse operation using a great number of direct temperature measurement points.
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Shih, Chao-Feng, and 施詔峰. "Meshless Weighted Least Square Method Application in Heat Transfer." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/85878794810970333400.
Full textAbstract:
碩士國立臺灣海洋大學
輪機工程系
96
Different from the traditional meshes or the elements, the approximate function is built on a series of dispersed nodes, and does not need to dependence on the limited meshes. MWLSM is based on least-squares method （LSM） and move least-squares （MLS） approximate foundation; it is a kind of high-efficient mesh-less method. The existing node leads into some auxiliary nodes, and eliminates the residuals with LSM between all nodes and some auxiliary places. The shape function fits and solves truly by MLS; therefore have higher accuracy than finite element method （FEM）. This method does not need gauss integrations; therefore it is rapid to calculate. MWLSM is extended to solve multi-dimensional convection-diffusion problems; We revise modified weighting function structural form in order to raise their efficiency. Numerical examples indicate that the elliptically structural form of shape function has better than the round in convergence and accuracy.
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Jang, Horng-Yung, and 張鴻源. "Application and Analysis of the Inverse Heat Transfer Estimation." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/72291931312991759377.
Full textAbstract:
博士中正理工學院
國防科學研究所
86
In traditional weapon system, primer is designed as igniter. The adequacy of primers as detonation of pyrotechnic ignition trains is very important to the performance of interior ballistics. Therefore, a better knowledge and understanding the dynamic behavior of primer combustion efficiency is essential in application and design. In the past, the estimation of heat flux was based on the reaction of composition of the primer combustion and used the experience modification formulation. In this study, two sets of experimental apparatus are facilitated to measured temperature history and four different inverse analysis algorithms which base on conjugate gradient and Kalman filter are used to obtain the unknown parameters simultaneously. At first, experimental temperature profiles of M42 primer have been analysed with Conjugate gradient methodology to obtain estimated heat flux. To enhance the estimation accuracy, a recursive input estimation algorithm is incorporated to estimation the unknown parameter with those experimental data. Then, the accuracy is examined by a one-dimension heat conduction problem with heat source. Comparisons are also made with results of the conjugate gradient method and exact calculations. Besides, this thesis is also to verify the suitability of the Kalman filter technique for inverse heat conduction problems by using experimental data. A series of experiments was conducted and comparisons were made between measurement information and estimations using Kalman filter algorithm. The conventional Kalman filter may induce unsatisfactory tracing error while applied to the time-varying heat flux tracking problem and how to compensate the time lag in the response of the filter in the key to improve estimation method. In order to reach this object, a combined adaptive Q Kalman and Kalman smoothing technique is used. By applying Beck and Scapa''s analysis modeling, some comparisons with other techniques are also made. The numerical results show the superior performance of this proposed technique.
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Hung, Chao-Kun, and 洪照坤. "Application of Heat Insulation Painting to Building Energy Saving." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/17061777626803325645.
Full textAbstract:
碩士國立彰化師範大學
電機工程學系
100
Insulation coating, composed of high polymer, can effectively reflect sunlight, decrease heat absorption and release the heat by radiation to insulate heat and decrease temperature for buildings. In order to compare reflection and insulation efficiency under the same temperature, the study adds mica powder and ceramic powder into insulation coating as stuffing materials. These two materials have the characteristics of heat resistance, low coefficient of thermal expansion and anti-heat conduction. The low-temperature experiment shows that room temperature decreases from 43.7℃ to 35.2℃ and heat insulation efficiency improves 19.45% after adding stuffing materials on the surface of iron-covered building comparing to the one without coating. The high temperature experiment shows that room temperature of building by insulation coating with stuffing material decreases from 64.1℃ to 59.6℃with 4.5℃ difference and 6.6% to 27% energy saving. The study confirmed that the insulation coating with stuffing materials could effectively improve heat insulation and indoor temperature, and therefore reach the purpose of energy saving.
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Peng, Zheng-Zi, and 彭政子. "Development and Application of Heat-resistant Banana Tart Filling." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/78y8a7.
Full textAbstract:
碩士國立屏東科技大學
食品科學系所
106
Abstract Student ID: M10536006 Title of Thesis: Development and Application of Heat-resistant Banana Tart Filling Total Page: 78 Name of Institute: National Pingtung University of Science and Technology Department of Food Science Graduate Date: July, 2018 Degree Conferred: Master Name of Student: ZHENG-ZI PENG Advisers: Dr. Chi-Ching Yang The Contents of Abstract in This Thesis: Bananas are an important agricultural product in Taiwan. Bananas often cause major losses to farmers during the prolific period. One of the main reasons is that bananas are susceptible to browning and it is not easy to manufacture food-processed agricultural products. Baked stuffing is a fairly marketable food product. There are two main problems with banana stuffing. The first problem is browning, and the second is heat resistance. The main purpose of this study is to solve the problem. A major problem, the research results include the development of heat-resistant and non-brown banana fillings that can be applied to egg tarts, bread stuffing, and cake fruit creams. The results of the study show that the use of a combination of citric acid 0.5%, ascorbic acid 0.5%, and trehalose 10%, together with the killing of clove, can successfully solve the browning problem of bananas and prevent browning during storage or within 10 days of refrigeration. The results before the killing of the pods showed that the 1% addition of Xanthan gum had a polyphenol oxidase (PPO) activity of 1228 (U/mg protein) and a browning degree (0.029), which was lower than that of the control group 5056 (U/ (mg protein), browning degree (0.031); PPO activity of the two groups were all close to 0, and the browning degree was 0.011 in the Xanthan gum group and 0.018 in the control group. In the heat resistance test, heat-resistant banana fruit fillings were prepared using edible gums (Xanthan gum, Cardland gum, Pectin, Carrageenan, and Gellan), and the percentage was increased by 0.5%, 0.75%, and 1.0%. The heat resistance increased, and the browning problem did not occur when the banana fruit filling with 1% Xanthan gum was baked at 200°C/180°C for 12 minutes, and the water roasted loss rate was 18.23%, which was lower than the control. The group had 25.76% with significant differences. After 6 weeks of storage, the total number of bacteria in the banana fruit filling approached 0 CFU/g. The result of a 7-point system of sensory evaluation (50 persons) showed that the average degree of banana egg tower overall acceptance was 4.94 (control group 4.04). There are currently no banana egg tart products on the market. The success of this research can create banana egg tart products that may be very popular among consumers, and it is believed that the problem of overproduction of some bananas can be solved. Keywords: Banana, Banana browning, Heat-resistant fruit filling, Enzymatic browning