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1
Henry, M. P. "Design methodology : Regenerative heat exchangers." Thesis, University of York, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379493.
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Goodman, Christopher L. "Modeling, validation and design of integrated carbon dioxide heat pumps and water heaters." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22560.
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Abushammala, Omran. "Optimal Helical Tube Design for Intensified Heat / Mass Exchangers." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0091.
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La recherche de solutions technologiques visant à minimiser la taille d’un dispositif, qualifiée d’intensification, est un objectif classique du génie des procédés. Dans ce mémoire, les possibilités d’intensification offertes par des tubes hélicoïdaux sont étudiées, à la fois pour des échangeurs de chaleur et de matière. L’utilisation de tubes hélicoïdaux en lieu et place de tubes droits présente en effet un intérêt à la fois en termes d’augmentation de la surface d’échange par unité de volume entre les deux fluides circulant dans l’échangeur et par la possibilité d’augmentation des transferts par génération de vortex de Dean dans les tubes. Un ensemble de simulations de mécanique des fluides numérique a été réalisé et confronté à des résultats expérimentaux. Au final, sur la base d’une démarche systématique faisant appel à des corrélations, une réduction volumique d’un facteur 8 est obtenue, tant pour les échangeurs de chaleur que pour les contacteurs à membranesThe search for technological solutions aimed at minimizing the size of a device, known as intensification, is a classic objective of process engineering. In this thesis, the intensification possibilities offered by helical tubes are studied, both for heat and mass exchangers. The use of helical tubes instead of straight tubes is indeed of interest both in terms of increasing the exchange surface per unit volume between the two fluids circulating in the exchanger and by the possibility of increasing the transfers by generating Dean vortices in the tubes. A set of CFD (Computational Fluid Dynamics) type simulations was carried out and compared with experimental results. In the end, on the basis of a systematic approach using correlations, a volume reduction of a factor of 8 was obtained, both for heat exchangers and for membrane contactors
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Leung, C. W. "The optimisation of the design of extended surface heat exchangers." Thesis, University of Sunderland, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234917.
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Tapia, Carlos F. "Second law and thermoeconomic aspects of heat exchanger design /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267546984182.
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Ozden, Ender. "Detailed Design Of Shell-and-tube Heat Exchangers Using Cfd." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608752/index.pdf.
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Traditionally Shell-and-tube heat exchangers are designed using correlation based approaches like Kern method and Bell-Delaware method. With the advances in Computational Fluid Dynamics (CFD) software, it is now possible to design small heat exchangers using CFD. In this thesis, shell-and-tube heat exchangers are modeled and numerically analyzed using a commercial finite volume package. The modeled heat exchangers are relatively small, have single shell and tube passes. The leakage effects are not taken into account in the design process. Therefore, there is no leakage from baffle orifices and no gap between baffles and the shell. This study is focused on shell side flow phenomena. First, only shell side is modeled and shell side heat transfer and flow characteristics are analyzed with a series of CFD simulations. Various turbulence models are tried for the first and second order discretization schemes using different mesh densities. CFD predictions of the shell side pressure drop and the heat transfer coefficient are obtained and compared with correlation based method results. After selecting the best modeling approach, the sensitivity of the results to the flow rate, the baffle spacing and baffle cut height are investigated. Then, a simple double pipe heat exchanger is modeled. For the double pipe heat exchanger, both the shell (annulus) side and the tube side are modeled. Last, analyses are performed for a full shell-and-tube heat exchanger model. For that last model, a small laminar educational heat exchanger setup is used. The results are compared with the available experimental results obtained from the setup. Overall, it is observed that the flow and temperature fields obtained from CFD simulations can provide valuable information about the parts of the heat exchanger design that need improvement. The correlation based approaches may indicate the existence of a weakness in design, but CFD simulations can also pin point the source and the location of the weakness.
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Brooks, Paul David Edwards. "The design of moving packed bed high temperature heat exchangers." Thesis, University of the West of England, Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321834.
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Madhavan, Srivatsan. "Review, Design and Computational Study of Some Compact Heat Exchangers." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511885027497222.
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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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Tomski, Thomas. "The design of shell-and-tube heat exchangers using expert systems." Thesis, University of Brighton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314803.
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Gezelius, Knut 1978. "Design of compact intermediate heat exchangers for gas cooled fast reactors." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/26911.
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Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004.Includes bibliographical references (p. 171-174).
Two aspects of an intermediate heat exchanger (IHX) for GFR service have been investigated: (1) the intrinsic characteristics of the proposed compact printed circuit heat exchanger (PCHE); and (2) a specific design optimizing economic and technical efficiency while coupling a supercritical CO2 Brayton power cycle to a helium cooled fast reactor core. In particular, the wavy channel friction factor and the effective conduction thickness between channels were evaluated by simulations using state of the art software (FluentTm). To support the competitiveness of the PCHE, it was directly compared to other potential IHX candidates with respect to performance and size for identical operating conditions. All PCHE modeling conservatively assumed straight channels and was carried out using an MIT in-house code. The PCHEs designed specifically for the He/S-CO2 cycle were designed to be deployed in a prestressed cast iron reactor vessel (PCIV) pod and to permit a net cycle efficiency of at least 40%. Optimization theory, sensitivity studies, and thermal-hydraulic constraints contributed to shaping the final design. The friction factor analysis showed that the correlations cited in the literature overestimate the value by approximately a factor of two. As regards the effective conduction thickness ratio, it was found to be around 0.6 for a 2.0 mm channel diameter. Since the value of the ratio employed in the MIT in-house code is 1.0, the results generated by the code should be conservative.
Comparing the competing IHX types clearly illustrated the advantages of using a compact design, thus favoring PCHEs and plate-fin designs. A maximum net cycle efficiency of 40.9% was achieved for the proposed cycle utilizing a low-pressure-drop reference core. The cost and core volume of this 600 MWt PCHE design were estimated to be $2.4M and 16.4 inm3, respectively. The largest uncertainty associated with the computations is whether the PCIV pod provides sufficient space for deployment of the PCHE, a blower, and other ancillary equipment. However, studies of PCHEs based on zig-zag channels indicate that the compactness can be further enhanced by a factor of 2 to 3 thanks to the increased heat transfer capability of the saw-tooth channel geometry. More research is needed to verify this projection.
by Knut Gezelius.
S.M.and S.B.
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Naik, S. "Thermal-hydraulic designs of finned heat-exchangers experiencing free or forced convection." Thesis, Cranfield University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379521.
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Soleimanikutanaei, Soheil. "Modelling, Design, and Optimization of Membrane based Heat Exchangers for Low-grade Heat and Water Recovery." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3921.
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Transport Membrane Condenser (TMC) is an innovative technology based on the property of a nano-scale porous material which can extract both waste heat and water from exhaust gases. This technology tremendously improves the efficiency of boilers and gas/coal combustors by lowering waste heat and increasing water recovery. Contaminants in the flue gases, such as CO2, O2, NOx, and SO2 are inhibited from passing through the membrane by the membrane’s high selectivity. The condensed water through these tubes is highly pure and can be used as the makeup water for many industrial applications. The goal of this research is to investigate the heat transfer, condensation rate, pressure drop and overall performance of crossflow heat exchangers. In this research, a numerical model has been developed to predict condensation of water vapor over and inside of nano-porous layers. Both capillary condensation inside the nanoscale porous structure of the TMC and the surface condensation were considered in the proposed method using a semi-empirical model. The transport of the water vapor and the latent heat of condensation were applied in the numerical model using the pertinent mass, momentum, turbulence and energy equations.
By using the proposed model and simulation procedure, the effect of various inlet parameters such as inlet mass flow rate, inlet temperature, and water vapor content of the inlet flow on the performance of the cross-flow TMC heat exchanger was studied to obtain the optimum performance of the heat exchangers at different working conditions. The performance of the TMC heat exchangers for inlet flue gas rate 40 to 120 kg/h, inlet water rate 60 to 140 kg/h, inlet flue gas relative humidity 20 to 90%, and tube pitch ratio 0.25 to 2.25 has been studied. The obtained results show that the water condensation flux continuously increases with the increase of the inlet flue-gas flow rate, water flow rate, and the flue-gas humidity. The total heat flux also follows the same trend due to the pronounced effect of the latent heat transfer from the condensation process. The water condensation flux and the overall heat transfer increase at the beginning for small values of the tube pitches and then decreases as the tube pitch increases furthermore. In addition to the cross-flow TMC heat exchangers, the performance of a shell and tube TMC heat exchanger for high pressure and temperature oxy-combustion applications has been investigated. The performance analysis for a 6-heat exchanger TMC unit shows that heat transfer of the 2-stage TMC unit is higher than the 2-stage with the same number of the heat exchanger in each unit.
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Al-Sahaf, Jamal A. "The influence of frosting on the optimum design of finned-tube evaporators." Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/917.
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Kamarad, Anthony. "Design and construction of a mobile equipment for thermal response test in borehole heat exchangers." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99558.
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In 2010, the Ground Source Heat Pumps (GSHPs) market in the European Union went up over one million (1 014 436 units at the end of 2010 according to EUROBSERV’ER 2011). In 2011, it was estimated around 1.25 million according to Bayer et al. (2012). With more than 378 000 units installed in 2010, according to the Swedish heat pump association (SVEP), the Swedish GSHPs market was the first in the EU. As for the French GSHPs market, it was estimated to 151 938 units in service in 2010, which propelled France at the third rank in the EU. However, despite a relatively important number of GSHPs installed in the whole EU, since 2008 GSHP sales have shrank. Even Sweden which has been the most competitive country sees its GSHP sales decline in the first quarter of 2012 (EUROBSERV’ER 2011). This report is the achievement of my Master of Science Thesis project. It also represents the end of my studies at INSA Lyon in France and concludes my degree in Energetic and Environment Engineering. This report deals with the improvement of a heat injection apparatus which is available at KTH (Royal Institute of Technology). This equipment is better known as Thermal Response Test (TRT) apparatus. This kind of equipment improves Borehole Heat Exchangers (BHE) design in terms of size and cost benefits. This technology is generally used to design GSHP installations in both domestic and industrial purposes. It allows to determine really important thermal BHE parameters: the thermal conductivity of the ground and the borehole thermal resistance. The report covers a theoretical description of TRT experiments, the reasons and objectives of such a project, the apparatus design and its construction. The last part is dedicated to a first experimental laboratory results and some problems met during the project course.
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Kroger, Detlev G. "Air-cooled heat exchangers and cooling towers : thermal-flow performance evaluation and design." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49822.
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Thesis (PhD)--Stellenbosch University, 2004.ENGLISH ABSTRACT: During the last 30 years I have been involved in the theory and practice of thermal engineering and in particular, in the areas of air-cooled heat exchangers and cooling towers for the power, refrigeration, process and petrochemical industries in South Africa and internationally. During this period, I have authored and co-authored more than 120 papers that were published in technical journals or presented at conferences nationally or internationally. Most of these papers are included in a manuscript entitled "Air-cooled Heat Exchangers and Cooling Towers", in which Ipresent a systematic approach to the thermal performance evaluation and design of industrial air-cooled heat exchangers and cooling towers. This original publication also includes the relevant practice applicable to the design of cooling systems, based on my experience as a consultant to industry. Design offices throughout the world presently follow our design methods, or at least employ many of our research results. Our work has furthermore contributed to the development of improved cooling system designs (e.g. new dephlegmator header designs), components (e.g. single-row flattened finned tubes) and product improvement and quality control (e.g. performance testing and measurement of thermal contact resistance between fin and tube during production). Many of our research findings have found application in the modification of existing cooling systems. The manuscript has also been used as reference work during the presentation of short courses to practising engineers and consultants in industry and to engineering graduates at the University of Stellenbosch. A two-volume edition of this manuscript was published by PennWell Corp., Tulsa, Oklahoma, USA in 2004.
AFRIKAANSE OPSOMMING: Gedurende die laaste 30 jaar was ek betrokke by die teorie en praktyk van lugverkoelde warmteoordraers en koeltorings vir die kragopwekkings-, verkoelings-, proses- en petro-chemiesenywerhede in Suid-Afrika sowel as in die buiteland. Gedurende hierdie periode was ek outeur en mede-outeur van meer as 120 publikasies wat in tegniese tydskrifte, of by plaaslike of oorsese konferensies aangebied is. Die meeste van hierdie publikasies vorm deel van 'n manuskrip getiteld "Air-cooled Heat Exchangers and Cooling Towers" waarin ek 'n sistematiese benadering tot die bepaling van die termiese vermoë en ontwerp van industriële lugverkoelde warmteoordraers en koeltorings aanbied. Hierdie oorspronklike publikasie bevat ook die relevante praktyk wat van toepassing is op verkoelingsaanlegte. Ontwerpkantore wêreldwyd volg tans hierdie ontwerpsmetodes, of gebruik ten minste baie van ons navorsingsresultate. Ons werk het verder bygedra tot die ontwikkeling van verbeterde verkoelingsaanlegte (bv. nuwe deflegmatore), komponente (bv. enkelbuisry platvinbuise ) en verbeterde produkte en kwaliteitskontrole (bv. toetsing van verkoelingsvermoë oftermiese kontakweerstand tussen vin en buis gedurende produksie). Baie van ons bevindinge het toepassing gevind in die modifikasie van verkoelingsaanlegte. Die manuskrip is ook as verwysing gebruik gedurende die aanbieding van kort kursusse aan ingenieurs in die praktyk en aan nagraadse studente aan die Universiteit van Stellenbosch. 'n Twee-volume uitgawe van die manuskrip is deur PennWell Corp., Tulsa, Oklahome, VSA in 2004 gepubliseer.
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Brusén, Niklas, and Jon Kristoffersson. "Automated Production of Air to Air Heat Exchangers : Robot Cell Design and Simulation." Thesis, Uppsala universitet, Industriell teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-326182.
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The aim of this thesis was to describe how a manual assembly process of polycarbonate sheets for heat exchangers can be automated with an industrial robot. The objectives were to design suitable robot cell concepts and simulate them to describe how the automated process could be done and to present which machines and equipment that could be used. Additionally, productivity rates and investment costs was to be calculated.The project started with a situation assessment and a literature review. Experts and suppliers of robotic equipment were consulted, and the results served as a basis for the concept generation process. Several concept ideas were evaluated, and three ideas using adhesive for the assembly were chosen for further studies and simulation. Existing products and machines were used in the designs when possible. By modeling and simulating the cells in simulation software, feasible cell designs was created, and cycle times were measured.The three proposed solutions all utilize an industrial robot, a vacuum gripper and adhesive as the assembly method. Two of the concepts has the robot attending different adhesive dispensing machines; one gantry and one conveyor. In the third concept, the robot applies the adhesive. The cell design that achieved the lowest cycle time in the simulations was the conveyor concept, with a cycle time of 21 seconds per sheet. The conclusion of the study is that investing in a robot cell would increase productivity.Syftet med detta arbete var att designa en robotcell anpassad för tillverkning av värmeväxlarpaket i moduler. Målet var att besvara hur tillverkningen av värmeväxlare kan automatiseras samt vilken robot och övriga verktyg och maskiner som kan användas. Vidare skulle den möjliga produktionstakten och investeringskostnaden för designförslagen beräknas. Arbetet inleddes med en nulägesanalys och en litteraturstudie. Ett flertal experter och leverantörer inom automationsområdet konsulterades. Resultaten från detta låg till grund för en konceptgenereringsprocess i vilken ett flertal designidéer togs fram. Tre av dessa designförslag valdes ut för vidare studier och simulering. Genom att modellera och simulera robotcellerna kunde de utformas realistiskt och möjliga cykeltider beräknas. De tre designförslagen använder alla en robotarm, ett vakuumgripdon samt lim som metod för monteringen. Två av koncepten består av en medelstor robotarm som betjänar en limappliceringsmaskin. I ena konceptet är det en kartesisk robot med limbord som används för limappliceringen, i det andra är det ett transportband som för plastskivan under ett antal limpistoler. Det tredje designförslaget låter en större robot, utrustad med verktygsväxlare, utföra alla moment i processen genom att den byter verktyg mellan vakuumgripdon och limpistol. Det koncept som uppnådde den lägsta cykeltiden i simuleringarna var lösningen med rullbandet, med en cykeltid på 21 sekunder per skiva. Studiens slutsats är att en investering i en robotcell skulle leda till ökad produktivitet jämfört med manuell produktion.
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Begum, Latifa. "Natural and mixed convection in a horizontal cylindrical annulus with and without fins on inner cylinder." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112556.
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Determination of the heat transfer coefficients for natural and mixed convection in horizontal annuli is important for designing double pipe heat exchangers and for energy storage systems. In part one and two of this study, the 2D numerical solution of the laminar natural convection of water in six internally finned horizontal annuli has been obtained. The fins are attached to the external surface of the inner cylinder. Only the symmetrical half of the horizontal annulus with three equally spaced longitudinal divergent solid and porous fins are considered. The parameters of the problem are Rayleigh number, fin height, permeability and porosity of the porous fin, etc. The above parameters are suitably varied to ascertain their effects on fluid flow and heat transfer. The results show that traditional solid fins provide much higher heat transfer rates compared to the porous fins. Part three of this work deals with mixed convective heat transfer (laminar natural and forced convections) of water in a vented annulus. The forced flow conditions are imposed by providing an inlet at the top and an outlet at the bottom. For various parameters of the problem, the average and local Nusselt numbers along the inner cylinder are calculated for water for both aiding and opposing flows. The fourth part of this study deals with numerical modeling of natural convection of nanofluids in a horizontal cylindrical annulus. Simulations are carried out for Cu-water nanofluids. The results, in general, show that nanoparticles systematically decrease the natural convective heat transfer coefficient on the inner cylinder. Practical and useful correlations are provided for calculating average heat transfer rates from the inner cylinder in the form of average equivalent thermal conductivity and average Nusselt number for all of the four cases discussed above. These correlations are new and will be helpful in designing heat exchangers.
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Villafañe, Roca Laura. "Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/34774.
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The path to future aero-engines with more efficient engine architectures requires advanced
thermal management technologies to handle the demand of refrigeration and lubrication. Oil
systems, holding a double function as lubricant and coolant circuits, require supplemental
cooling sources to the conventional fuel based cooling systems as the current oil thermal
capacity becomes saturated with future engine developments. The present research focuses on
air/oil coolers, which geometrical characteristics and location are designed to minimize
aerodynamic effects while maximizing the thermal exchange. The heat exchangers composed
of parallel fins are integrated at the inner wall of the secondary duct of a turbofan. The
analysis of the interaction between the three-dimensional high velocity bypass flow and the
heat exchangers is essential to evaluate and optimize the aero-thermodynamic performances,
and to provide data for engine modeling. The objectives of this research are the development
of engine testing methods alternative to flight testing, and the characterization of the
aerothermal behavior of different finned heat exchanger configurations.
A new blow-down wind tunnel test facility was specifically designed to replicate the engine
bypass flow in the region of the splitter. The annular sector type test section consists on a
complex 3D geometry, as a result of three dimensional numerical flow simulations. The flow
evolves over the splitter duplicated at real scale, guided by helicoidally shaped lateral walls.
The development of measurement techniques for the present application involved the design
of instrumentation, testing procedures and data reduction methods. Detailed studies were
focused on multi-hole and fine wire thermocouple probes.
Two types of test campaigns were performed dedicated to: flow measurements along the test
section for different test configurations, i.e. in the absence of heat exchangers and in the
presence of different heat exchanger geometries, and heat transfer measurements on the heat
exchanger. As a result contours of flow velocity, angular distributions, total and static
pressures, temperatures and turbulence intensities, at different bypass duct axial positions, as
well as wall pressures along the test section, were obtained. The analysis of the flow
development along the test section allowed the understanding of the different flow behaviors
for each test configuration. Comparison of flow variables at each measurement plane
permitted quantifying and contrasting the different flow disturbances. Detailed analyses of the
flow downstream of the heat exchangers were assessed to characterize the flow in the fins¿
wake region. The aerodynamic performance of each heat exchanger configuration was
evaluated in terms of non dimensional pressure losses. Fins convective heat transfer
characteristics were derived from the infrared fin surface temperature measurements through a
new methodology based on inverse heat transfer methods coupled with conductive heat flux
models. The experimental characterization permitted to evaluate the cooling capacity of the
investigated type of heat exchangers for the design operational conditions. Finally, the
thermal efficiency of the heat exchanger at different points of the flight envelope during a
typical commercial mission was estimated by extrapolating the convective properties of the
flow to flight conditions.Villafañe Roca, L. (2013). Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34774
TESIS
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Lindstrom, Joel David. "Design and evaluation of compact heat exchangers for hybrid fuel cell and gas turbine systems." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/lindstrom/LindstromJ0505.pdf.
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Akan, Akaninyene. "Theoretical design of printed circuit heat exchangers applied to a conceptual liquid fluoride reactor." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406029933.
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Stewart, Susan White. "Enhanced Finned-Tube Condenser Design and Optimization." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5289.
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Enhanced Finned-Tube Condenser Design and Optimization
Susan W. Stewart
173 pages
Directed by Dr. Sam V. Shelton
Finned-tube heat exchangers are widely used in space conditioning systems, as well as any other application requiring heat exchange between liquids and gases. Their most widespread use is in residential air conditioning systems. Residential systems dictate peak demand on the U.S. national grid, which occurs on the hot summer afternoons, and thereby sets the expensive infrastructure requirement of the nations power plant and electrical distribution system. In addition to peak demand, residential air conditioners are major energy users that dominate residential electrical costs and environmental impact.
The only significant opportunity for electrical power use reduction of residential air conditioners is in technology improvement of the finned-tube heat exchangers, i.e., condenser and evaporator coils. With the oncoming redesign of these systems in the next five years to comply with the regulatory elimination of R-22 used in residential air conditioners today, improvement in the design technology of these systems is timely.
An air conditioner condenser finned-tube coil design optimization methodology is derived and shown to lead to improved residential air conditioner efficiency at fixed equipment cost. This nonlinear optimization of the 14 required design parameters is impractical by systematic experimental testing and iteration of tens of thousands condenser coils in an air conditioning system. The developed methodology and results can be used in the redesign of residential systems for the new mandated environmentally friendly refrigerants and to meet increasing regulatory minimum system efficiencies.
Additionally, plain fins and augmented fins, (louvered), are compared using the developed model and optimization scheme to show the effect of the augmentation on system performance. Furthermore, an isolated condenser model was developed using condenser entropy generation minimization as the figure of merit to minimize the model complexity and computation time. Isolated model optimizations are compared with the system model optimum designs.
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Taylor, Creed. "Measurement of Finned-Tube Heat Exchanger Performance." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4890.
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Finned-tube heat exchangers are predominantly used in space conditioning systems, as well as other applications requiring heat exchange between two fluids. One important widespread use is in residential air conditioning systems. These residential cooling systems influence the peak demand on the U.S. national electrical system, which occurs on the hot summer afternoons, and thereby sets the requirement for the expensive infrastructure requirement of the nations power plant and electrical distribution system. In addition to this peak demand, these residential air conditioners are major energy users that dominate residential electrical costs and environmental impact.
The design of finned-tube heat exchangers requires the selection of over a dozen design parameters by the designer. The refrigerant side flow and heat transfer characteristics inside the tubes have been thoroughly studied. However, the air side flow around the tube bundle and through the fin gaps is much more complex and depends on over a dozen design parameters. Therefore, experimental measurement of the air side performance is needed.
First this study built an experimental system and developed methodology for measuring the air side heat transfer and pressure drop characteristics of fin tube heat exchangers. This capability was then used to continue the goal of expanding and clarifying the present knowledge and understanding of air side performance to enable the air conditioner system designer in verifying an optimum fin tube condenser design.
In this study eight fin tube heat exchangers were tested over an air flow face velocity range of 5 ?? ft/s (675-1600cfm). The raw data were reduced to the desired heat transfer and friction data, j and f factors. This reduced heat transfer and friction data was plotted versus Reynolds number and compared. The effect of fin spacing, the number of rows and fin enhancement were all investigated. The heat transfer and friction data were also plotted and compared with various correlations available from open literature. The overall accuracy of each correlation to predict experimental data was calculated. Correlations by C.C. Wang (1998b, 1999) showed the best agreement with the data. Wangs correlations (1998b, 1999) were modified to fit the current studys data.
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Cheng, Tao 1975. "Nonlinear observer design using contraction theory with application to heat exchangers having varying phase transition." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36177.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.Includes bibliographical references (leaves 90-91).
Thermo-fluid systems such as air conditioning and refrigeration systems are widely used in residential, commercial, and industrial applications. By the end of the 20th century, nearly 70 percent of U.S. households had air conditioning, and 99.5 percent had at least one refrigerator. Advanced control and monitoring of the thermo-fluid systems has become an inevitable but challenging issue in this century as the energy efficiency has become increasingly important. Air conditioning and refrigeration systems transport heat by means of refrigerant, repeating phase transition, which is a highly nonlinear process. Mixture of vapor and liquid refrigerant distributed in heat exchangers makes the process dynamics highly complex, including many state variables that are important for stringent control but are not directly measurable. In this thesis, nonlinear observers for estimating those inaccessible state variables are designed and are applied to the control and monitoring of an air conditioning system. First heat exchanger dynamics including complex phase transition phenomena are analyzed. It is shown that the order of the system varies dynamically depending on the distribution of vapor and liquid, which makes the system a varying-order switched system.
(cont.) Second, a switched observer for the varying order switched system is designed by augmentation using real system dynamics. The convergence conditions of the switched observer are derived using contraction theory. This observer design is applied to heat exchangers of an air conditioning system. The nonlinear observer design of the heat exchanger with invariant phase transition is validated by extensive experimental tests using a residential air conditioner. For the switched observer of the heat exchanger with varying phase transition, simulation validation is conducted by using the parameters from the real air conditioning system. Finally, this heat exchanger observer is applied to lubrication oil monitoring and nonlinear control for the air conditioning systems. A lubrication oil circulation observer for estimating oil concentration and oil amount in refrigerant compressors is developed based on state observers of heat exchangers. It is validated by experimental tests and can be applied directly to residential and commercial air conditioning and refrigeration systems to improve reliability of the systems.
by Tao Cheng.
Ph.D.
25
Peronski, Lukasz. "Application of computational fluid dynamics in the design of heat exchangers for domestic central heating boilers." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612612.
Full textAbstract:
The aim of this study is to investigate the possible use of commercial Computational Fluid Dynamics (CFD) software in the design process of a heat exchanger for a domestic gas boiler. Fluid flow and heat transfer CFD simulations have been performed and validated. In general, a good agreement between the CFD simulations and the experimental results was observed. The porous media approach was used for approximating the water flow resistance characteristics in the sections of the heat exchanger in the flow distribution problems. This was in cases in which the direct CFD simulations of the water flow through these sections of the heat exchanger would require very large numerical meshes and computational resources. Also a method for designing a water flow distributor for the sectional parallel now heat exchanger is proposed. The method is based on Bernoulli's equation with the flow resistance characteristics of a single section of the heat exchanger gained from the CFD simulation of the water now through a single section of this heat exchanger. The performed CFD analyses provide very useful information with regards to the operational parameters and conditions in the heat exchanger under investigation, which would otherwise be very difficult. if not impossible, to obtain. Despite the great potential usefulness of the CFD simulation In the design process of heat exchangers, it is still not always considered a clear choice for use in the boiler industry, in order to aid the design process of heat exchangers for domestic central heating boilers. This is due to the relatively high cost of the CFD analyses and the fact that the boiler industry traditionally relies on design procedures based primarily on experimental techniques
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Carman, Bradley Gene. "Design of a high effectiveness ceramic micro-channel heat recuperator for micro-turbine application." Honors in the Major Thesis, University of Central Florida, 2002. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/262.
Full textAbstract:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Engineering
Mechanical Engineering
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Chen, Minghui. "DESIGN, FABRICATION, TESTING, AND MODELING OF A HIGH-TEMPERATURE PRINTED CIRCUIT HEAT EXCHANGER." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431072434.
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Yekoladio, Peni Junior. "Thermodynamic optimization of sustainable energy system : application to the optimal design of heat exchangers for geothermal power systems." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/31615.
Full textAbstract:
The present work addresses the thermodynamic optimization of small binary-cycle geothermal power plants. The optimization process and entropy generation minimization analysis were performed to minimize the overall exergy loss of the power plant, and the irreversibilities associated with heat transfer and fluid friction caused by the system components. The effect of the geothermal resource temperature to impact on the cycle power output was studied, and it was found that the maximum cycle power output increases exponentially with the geothermal resource temperature. In addition, an optimal turbine inlet temperature was determined, and observed to increase almost linearly with the increase in the geothermal heat source. Furthermore, a coaxial geothermal heat exchanger was modeled and sized for minimum pumping power and maximum extracted heat energy. The geofluid circulation flow rate was also optimized, subject to a nearly linear increase in geothermal gradient. In both limits of the fully turbulent and laminar fully-developed flows, a nearly identical diameter ratio of the coaxial pipes was determined irrespective of the flow regime, whereas the optimal geofluid mass flow rate increased exponentially with the Reynolds number. SeveORCs were observed to yield maximum cycle power output. The addition of an IHE and/or an Oral organic Rankine Cycles were also considered as part of the study. The basic types of the FOH improved significantly the effectiveness of the conversion of the available geothermal energy into useful work, and increased the thermal efficiency of the geothermal power plant. Therefore, the regenerative ORCs were preferred for high-grade geothermal heat. In addition, a performance analysis of several organic fluids was conducted under saturation temperature and subcritical pressure operating conditions of the turbine. Organic fluids with higher boiling point temperature, such as n-pentane, were recommended for the basic type of ORCs, whereas those with lower vapour specific heat capacity, such as butane, were more suitable for the regenerative ORCs.Dissertation (MEng)--University of Pretoria, 2013.
Mechanical and Aeronautical Engineering
unrestricted
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Sizani, Xolile L. "Evaluate the use of elliptical finned tubes in heat exchanger design and performance : 'the structural characteristics of finned tubes'." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51748.
Full textAbstract:
Thesis (MEng)--University of Stellenbosch, 2000.ENGLISH ABSTRACT: This report describes the Experimental and Numerical Investigations conducted, during the determination of the structural mechanics of elliptical tubes, viz. the F- and the Atubes. This report is requested in an endeavour to assist Sasol, who is currently busy developing and updating specifications on Air Cooled Heat Exchangers. The objectives of this report therefore are to : (1) determine the strength and the effectiveness of the tube-to-tube-sheet joints. (2) determine the allowable pressure limits on the tubes and (3) investigate the effects of thermal load and vibration on the tube bundle. A series of experiments were conducted to meet these objectives. From a Shear Load experiment it was found that the maximum allowable axial load on the Fand the A-tube is 14.55 kN and 20. 86 kN respectively. Fin Plates were found to have little effect on the bending strength of the tube, w~ilst they have significant effect on the resistance to volumetric expansion of the tube. In fact the more fins per unit length the greater the resistance to volumetric expansion of the tube. These conclusions were drawn from Bending and Pressure Load experiments respectively and supported by FEM analysis of the tube using NASTRAN. When the design pressure limit given by the manufacturer (GEA Air Cooled Systems), were tested using FEM analysis, it was found that they cause no significant deformation and failure of the tubes. Thermal stresses on the tube bundle greatly affect the first tube in the first row (row closest to the flanges) of the tube bundle and it is recommended that provision for thermal expansion be made to reduce these stresses. To reduce vibrations induced by the fan, it is recommended that the natural frequency of the tube bundle must not equal the number of blades (N) times the angular frequency (co) of the fan, or multiples thereof, of each mode of vibration.
AFRIKAANSE OPSOMMING: Hierdie tesis beskrywe die Numeriese en Eksperimentele ondersoeke na die sterkte van elliptiese verkoelingsbuise, naamlik die F- en A- tipes. Hierdie werk sal Sasol, wat huidiglik besig is met die opgradering, van spesifikasies vir lugverkoelde hitteuitruilers van nut wees. Die doelwitte van hierdie tesis is om: (1) die sterkte en effektiwiteit van die buis laste was die buis and die buisplaat verdind, te ondersoek, (2) die toelaatbare druklimiete, sowel as (3) die effek wat hitte en vibrasie op 'n buisbundel het, te ondersoek. 'n Reeks eksperimente is uitgevoer om hierdie doelwitte te bevredig. 'n Skuifbelastingseksperiment het aangedui dat die toelaatbare krag wat op 'n F- en A-buis respektiewelik aangewend kan word 14.55 kN en 20.86 kN is. Die ondersoek het aangetoon dat vinne geen noemenswaardige effek op die buigsterkte van die buise gehad het nie, maar dat dit 'n aansienlike verstywingseffek teen volumetriese verandering as gevolg van interne druk, gehad het. Hierdie gevolgtrekkings is bereik deur die Druk- en Buigtoetse wat numeries bevestig is met die NASTRAN eindige element analise (EEA) pakket. EEA het aangetoon dat die druklimiete voorgeskryf deur die buisvervaardiger (GEA Air Cooled Systems) nie noemenswaardige vervorming van die buise tot gevolg gehad het nie. Termiese belastings het 'n groot invloed op die eerste buise (die rye naaste aan die flense) van 'n buisbundel. Die invoeging van uitsettingslaste word aanbeveel om die spannings hier te verminder. Om vibrasie van die buisbundel te verhoed word aanbeveel dat die resonansfrekwensie van die buisbundel nie gelyk is aan die aantal lemme (N) vermenigvuldig met die rotasie frekwensie (co)van die waaier vir elke vibrasiemode.
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Mylavarapu, Sai Kiran. "Design, Fabrication, Performance Testing, and Modeling of Diffusion Bonded Compact Heat Exchangers in a High-Temperature Helium Test Facility." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1321996306.
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Bottau, Francesco. "Design and optimization af a race car cooling system." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Find full textAbstract:
The aim of this thesis is the design and the optimization of water radiator for the Tatuus F3 race car.
Tatuus is a racing car manufacturer which designs, produces and sells cars for different racing categories.
In a race car is essential that weight and occupied volume are kept as low as possible. This requirement is achieved by optimizing the vehicle’s components. For this reason, Tatuus commissioned a project focused on the optimization of heat exchangers. It is very important that the flow inside every radiator is as uniform as possible, to make it works in the most efficient way. With this respect, if in some channels the flow-rate is low or nil, they do not contribute to
the cooling process, hence represent a waste of space and weight.
To avoid this, it is crucial that inlet and outlet collectors have a shape such that the flow is distributed
almost uniformly inside each channel. This optimization can be obtained simulating different radiator configuration with CFD software and analyzing the internal flow distribution.
Using simulation solutions, it was possible to design radiators that guarantee a sufficiently uniform
flow.
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Subramaniam, Vishwanath. "Design of Air-cooled Microchannel Condensers for Mal-distributed Air Flow Conditions." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5088.
Full textAbstract:
Air-cooled condensers are routinely designed for a variety of applications, including residential air-conditioning systems. Recent attempts at improving the performance of these heat exchangers have included the consideration of microchannel tube, multilouver fin heat exchangers instead of the more conventional round tube-plate fin designs. In most packaged air-conditioning systems, however, the condenser surrounds the compressor and other auxiliary parts in an outdoor unit, with an induced draft fan at the top of this enclosure. Such a configuration results in significant mal-distribution of the air flow arriving at the condenser, and leads to a decrease in performance. This work addresses the issue of mal-distribution by adapting the air-side geometry to the expected air flow distribution. A microchannel tube, multilouver fin condenser is first designed to transfer the desired heat rejection load for an air-conditioning system under uniform air flow conditions. Tube-side pass arrangements, tube dimensions, and fin and louver geometry are varied to arrive at a minimum mass, 2.54 kg condenser that delivers the desired heat load of 14.5 kW. The design model is then used to predict the performance of the condenser for a variety of air flow distributions across the heat exchanger. It is found that for a 50% air flow mal-distribution, the required condenser mass increases to 2.73 kg. The air-side geometry (fin density and height) of the condenser is then systematically changed to optimally distribute the air-side surface area across the condenser to best address the mal-distributed air flow. It is found that linear fin density and height variations from the mean value of 40% and 20%, respectively, keeping the mean fin density and height the same, reduce the required condenser mass to 2.65 kg even for this mal-distributed air-flow case. The influence of geometry variations on heat transfer coefficients, fan power and other performance measures is discussed in detail to guide the judicious choice of surface area and tube-side flow area allocations for any potential air flow mal-distribution. The results from this study can be used for the design of air-cooled condensers under realistic flow conditions.
33
Pietersen, Richard Gordon. "Thermoelectric cooling for microwave transmitters located at remote sites." Thesis, Cape Technikon, 1992. http://hdl.handle.net/20.500.11838/2158.
Full textAbstract:
Thesis (MDiploma (Mechanical Engineering))--Cape Technikon, 1992.An investigation into the use of thermoelectric cooling energised by photovoltaic (PV) panels for removing sensible heat from electronic telecommunications equipment. The thermoelectric cooler consists of a solid-state heat pump which operates on the principle of the Peltier effect. The thermoelectric device transfers heat through a cold sink to ambient outside air via a hot sink. A major prerequisite was that the system should be selfsufficient in terms of power because the sites for the microwave transmitters are often remote. Solar power was the only alternative source of energy and the cooler was designed to accept direct current from PV panels which are usually used to power transmitters on distant locations. The cooling device had to be reliable, virtually maintenance-free and simple to repair.
34
Bradley, Stuart Edward. "Fouling resistant heat exchanger design." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239799.
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Lazzara, David S. (David Sergio) 1980. "Synergistic diffuser/heat-exchanger design." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/16660.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.Includes bibliographical references (p. 85).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
The theoretical and numerical evaluation of synergistic diffusing heat-exchanger design is presented. Motivation for this development is based on current diffuser and heat-exchange technologies in cogeneration plants, which require a large geometric footprint to generate steam using gas-turbine exhaust. A compact design is hypothesized to replace these technologies using synergistic design concepts. An investigation into the feasibility of such design concepts are conducted, providing pressure-recovery, viscous losses and thermal energy extraction sensitivities to cooling and annular blade geometry variations. Results show promising diffusion and heat-transfer capabilities that match or surpass current design performance. Proposed configurations are outlined based on these results that compare favorably to a baseline industrial cogeneration application.
by David S. Lazzara.
S.M.
36
Brum, Ruth da Silva. "Teoria Construtal e desempenho térmico de Trocadores de Calor Solo-Ar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/153247.
Full textAbstract:
Trocadores de Calor Solo-Ar (TCSA) são dispositivos usados para melhorar o condicionamento térmico de ambientes construídos. Eles funcionam através da ventilação do ar por um ou mais dutos enterrados, utilizando o solo como fonte ou sumidouro de calor. Em virtude da defasagem entre as temperaturas do ar e das camadas superficiais da Terra, é possível resfriar o ar no verão e aquecê-lo no inverno. Seus princípios de operação baseiam-se na mecânica dos fluidos e transferência de calor, áreas onde a teoria Construtal tem sido usada para melhorar o desempenho, ou reduzir imperfeições, de vários sistemas térmicos, após uma estratégica análise de suas geometrias (ou de seu design), também chamada de método Design Construtal que se fundamenta na lei construtal. Dessa lei, projetos em engenharia devem começar, por exemplo, descobrindo as arquiteturas que facilitam o escoamento entre uma fonte pontual e um volume, ou vice-versa. Explorando esses conceitos para TCSA, onde a corrente é o calor que flui entre os dutos e o solo, esta tese objetiva centralmente avaliar o desempenho térmico desses dispositivos em função de possíveis desenhos de suas estruturas. Particularmente, isso foi feito: (1) usando um duto e variando seu diâmetro e vazão de ar; (2) inserindo novos dutos, até um total de cinco, mantendo a vazão de ar constante, e estudando diversas disposições geométricas. Numericamente, foram empregados dois modelos testados e validados a partir de dados experimentais, que foram simulados no código comercial de dinâmica dos fluidos computacional, FLUENT, o qual baseia-se em métodos de volumes finitos. As geometrias e malhas foram geradas no software GAMBIT. Dos resultados numéricos, esta tese também avançou desenvolvendo novos modelos para o conceito de potencial térmico instantâneo, que é uma medida das diferenças de temperatura entre a saída e a entrada dos dutos de TCSA. Descobriu-se que estes modelos podiam ser simplificados em termos de funções senoidais, facilitando análises e definições analíticas subsequentes, criando um quadro resumo para grandes volumes de dados simulados. Das avaliações dos resultados nos estudos com um duto, foram encontradas faixas para a obtenção de rendimentos térmicos anuais estimados em pelo menos 80%, com mudanças no diâmetro e/ou vazão do ar. Analisando múltiplos dutos, foram reveladas melhorias significativas de rendimento com: (1) o aumento no número de dutos; (2) a redução, até certos limites, da razão entre os espaçamentos verticais e horizontais entre eles; (3) a ampliação da razão entre o volume da instalação e o volume do domínio computacional. Destaca-se, ainda, que em todos os casos foram calculados balanços energéticos, com a estimativa das taxas (e quantidade) de calor trocado, bem como da energia elétrica consumida pelos ventiladores, mostrando sua viabilidade no condicionamento de ar com redução do consumo de energia elétrica.The Earth-Air Heat Exchangers (EAHE) are devices used to improve the thermal conditions of built environments. They work by blowing the air inside buried ducts to use the soil as heat source or sink. Due to a phase difference between the air and ground temperatures, it is possible to cool the air in the summer and heat it in the winter. These operating principles are based on the areas of fluid mechanics and heat transfer, where the Constructal theory has been used to improve the performance, or reduce imperfections, of several thermal systems, after a strategic evaluation of their geometries (or their design), also called Constructal Design method, which is anchored by the constructal law. From this law, engineering projects should begin, for example, finding the architectures which ease the flow between a source point and a volume, or vice versa. Bringing these concepts to EAHE, where the current is the heat which flows between the ducts and the soil, this thesis mainly aims to assess the thermal performance of EAHE due to possible designs of their layouts. Particularly, this was done by: (1) adopting one duct and varying its diameter and/or the air flow; (2) using up to five ducts, keeping the air flow constant, and studying various geometric shapes. Numerically, two models were used, which have been tested and validated from experimental data, and the simulations were done in the CFD software FLUENT, which is based in the finite volume methods. The geometries and meshes were generated by the software GAMBIT. From the numerical results, this thesis also pursued developing new models for the concept of the instantaneous thermal potential, which is a measure of the temperatures differences between the ducts outlet and inlet. It was found that these models can be simplified in terms of sinusoidal functions, helping analysis, definitions, and creating a framework to summarize large volumes of simulated data. From the evaluation of the data in the studies with one duct, ranges for changes in their diameter and/or air flow were found to obtain at least 80% of estimated annual efficiency. Analyzing multiple ducts, significant improvements in efficiency were also obtained by: (1) increasing the number of ducts; (2) reducing, to some extent, the ratio between their vertical and horizontal spacings; (3) increasing the ratio between the installation volume and the computational domain. It should also be highlighted that in all cases the energy balances were computed, to find the rates (and amounts) of exchanged heat, as well as the electric energy consumed by the fans, showing the economic viability of using EAHE as devices for air conditioning.
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Kotjabasakis, E. "Design of flexible heat exchanger networks." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235140.
Full textAbstract:
Design for process flexibility is an industrially important topic so it is not surprising that it is attracting much research work. Given the size of the problem it is also not surprising that workers have concentrated on heat exchanger networks, which can be considered to be a self-contained sub-problem. Unfortunately, recent research has suffered from a number of major drawbacks. Problem formulation has often been unrealistic. Proposed procedures tend to be 'clinical' rather than practical. Academic research has often been conducted without proper consideration of the industrial environment. Very few research results have been tested on full scale industrial problems. In this thesis a new problem formulation and new solution techniques are presented. They have been designed to fulfil the needs of industry. In problem formulation it is recognised that the specification of flexibility is primarily an economic problem. The amount of flexibility industry will demand is a function of how much it costs. The methodology developed here allows both, the flexibility cost and the existing trade-off between flexibility needs, capital costs and energy costs to be fully evaluated. Flexibility problem formulation is mainly based on Multiple Base Cases. Different plant operating scenarios are set and a design found that is able to satisfy each case. This is a formulation that has found a wide acceptance in industry. To be industrially practical, process design techniques must be intelligible to the non-specialist. The techniques developed here are simple and straightforward and give insight. Two new design techniques have been developed. The first of these is 'Downstream Paths'. These are used to identify and evolve the network structures that permit cost effective flexibility. The second technique is 'Sensitivity Tables'. These can be used to analyse the performance of a given structure. In addition they determine the cost effective modification to elements of the structure which provide the specified flexibility needs. The technique is rapid, simple to apply and easy to repeat. Consequently, many scenarios can be screened without much effort and a cost profile developed in order to evaluate the cost trade-off described above. The approach proposed in this thesis, involving the new problem formulation and solution techniques, has been applied to a number of case studies of industrial scale. These case studies have covered problems as diverse as catalyst deactivation, fouling, and plant debottlenecking. One major spin-off from the work is a new approach to the design of heat exchanger networks subjected to fouling. Large potential savings have been identified.
38
Astrouski, Ilya. "Polymeric Hollow Fiber Heat Exchanger Design." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-240499.
Full textAbstract:
This Ph.D. thesis is focused on theory and experimental investigations developing of new knowledge about polymeric hollow fiber heat exchanger (PHFHE). The state-of-the-art study of plastic heat exchangers shows that their usage is limited by several niches where their advantages significantly dominates, or where the use of non-plastic competitors is not impossible. On the other hand, plastic heat exchangers (and PHFHEs in particular) are devices of increasing interest. It is shown that use of small tubes (fibers) allows PHFHEs to be more competitive than conventional plastic heat exchangers. Small hydraulic diameter of a fiber causes high heat transfer coefficients, reduces thermal resistance of plastic wall and allows it to create light and compact design. Detailed study of fluid flow and heat transfer inside the hollow fiber showed that conventional approaches for single-phase laminar flow can be utilized. Poiseuille number equal to 64 and Nussel number about 4 are recommended to be used to predict pressure drops and heat transfer coefficient, respectively. Additional attention should be paid to careful determination of fiber diameter and liquid properties (viscosity). Scaling effects, such as axial heat conduction, thermal entrance region and viscous dissipation can be neglected. The study of outside heat transfer showed that heat transfer on fiber bunches are intense and are competitive to contemporary compact finned-tube heat exchangers. The Grimson approach showed clear correlation with experimental results and, thus is recommended to predict heat transfer coefficients on fiber bunches. Two types of fouling (particulate- and biofouling) of outer fiber surface were experimentally studied. It was found that particulate fouling by titanium oxide particles is not intense and deposits can be removed relatively easy. However, fouling is much more intense when it is associated with biofouling caused by wastewater. In this case, smooth and low-adhesive surface of plastic is not sufficient precaution to prevent deposit formation.
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Magdanz, Alex, and Michael Schiefer. "Heat Exchanger Design in Mobile Machines." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199878.
Full textAbstract:
This paper examines the model-based design of thermal systems in mobile machines with a focus on heat exchanger design. An industry project is described in which the vapor compression cycle for the air-conditioning system was modeled using the software SimulationX. By modeling heat exchanger sections separately, multiple flow arrangements could be tested without the need for physical prototypes. The paper presents this work in the context of the full model-based design process including extensions for hardware in the loop (HiL) testing of control units and operator training using virtual machines.
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O'Young, D. Lionel. "Constrained heat exchanger network : targeting and design." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386405.
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Beautyman, Alan Clive. "The design of flexible heat exchanger networks." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/7586.
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Guo, Kunpeng. "Optimisation of plate/plate-fin heat exchanger design." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/optimisation-of-plateplatefin-heat-exchanger-design(e019a7a5-4be1-4350-b219-3387fd12f7d1).html.
Full textAbstract:
With increasing global energy consumption, stringent environmental protection legislation and safety regulations in industrialised nations, energy saving has been put under high priority. One of the most efficient ways of energy reduction is through heat transfer enhancement for additional heat recovery. Applying compact heat exchanger is one of the main strategies of heat transfer enhancement. However, the application of compact heat exchangers is prohibited by the lack of design methodology. Therefore, the aim of this research is to tackle the problem of developing optimisation methodologies of plate/plate-fin heat exchanger design. A mathematical model of plate-fin heat exchanger design is proposed to consider fin type selection with detailed geometry and imposed constraints simultaneously. The concept of mix-and-match fin type combinations is put forward to include all possible fin type combinations in a heat exchanger. The mixed integer nonlinear programming (MINLP) model can be converted to a nonlinear programming (NLP) model by employing continuous heat transfer and pressure drop correlations and considering the basic fin geometric parameters as continuous variables. The whole optimisation is based on volumetric minimisation or capital cost minimisation and completed by CONOPT solver in GAMS. Case studies are carried out to demonstrate the effectiveness and benefits of the new proposed methodology. For plate heat exchangers, the design methodology is developed on the basis of plate-fin heat exchanger methodology, and takes phase change, plate pattern selection, flow arrangement and pressure drop constraints simultaneously. The phase change problem is tackled by dividing the whole process into several subsections and considering constant physical properties in each subsection. The performances of various flow arrangements are evaluated by correction factors of logarithmic mean temperature difference. For two-phase conditions, the heat transfer and pressure drop performance are predicted by continuous two-phase Nusselt number and Fanning friction factor correlations to avoid the MINLP problem. The optimisation is solved by CONOPT solver as well. The feasibility and accuracy of the new proposed methodology is examined by case studies.
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Cetin, Murat. "Design And Experimental Investigation Of Microchannel Heat Exchanger." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611856/index.pdf.
Full textAbstract:
Due to the high performance of electronic components, the heat generation
is increasing dramatically. Heat dissipation becomes a significant issue in
efficiency promotion and stable operation. Microchannels are of current interest
for use in heat exchangers where very high heat transfer performance is desired.
Microchannels provide high heat transfer coefficients because of their small
hydraulic diameters. In this study, the design and experimental investigation of
fluid flow and heat transfer in a microchannel heat exchanger is conducted. Water
and air are used as the working fluids and flowed through microchannels. The heat
exchanger has been designed with 6 rows of microchannels for water flow and 7
rows of microchannels for forced flow of air. The heights of the microchannels are
4 mm and 10 mm respectively for water and air flows. Microchannels are brazed
to form the heat exchanger. For forced convection cooling with air, a military fan
is used. A constant heat source has been specifically designed for experiments.
Water flow and heat transfer experiments are conducted on the aluminum
microchannel heat exchanger. An experimental method of imposing a constant
heat flux to water prior to the entrance to the microchannel heat exchanger, to
adjust the inlet temperatures is used.
v
From the data obtained, the rate of heat transfer, effectiveness and various
other parameters have been computed and the results have been compared with
those from an available commercial heat exchanger. The results indicate that the
heat exchanger performs well and provides 681 W of cooling in a volume 677.6
cm3 while the commercial heat exchanger provides 702.5 W of cooling in a
volume 2507.5 cm3. In addition, air-side Colburn modulus has been obtained with
respect to Reynolds number.
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Zhu, Xin X. "Strategies for optimization in heat exchanger network design /." Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phz638.pdf.
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Mote, R. T. "Heat exchanger design in a hot-water store." Thesis, Cranfield University, 1991. http://dspace.lib.cranfield.ac.uk/handle/1826/10999.
Full textAbstract:
The behaviour of natural convective buoyancy-driven flows within
a hot-water store due to the forced passage of colder water
through the heat-exchanger's pipe are reviewed in the light of
recent advances in experimental
throughout the literature. The
exchanger designs, for natural
unworkable for the engineer
complication arises because the
heat exchanger are sensitive to
and numerical studies, reported
empirical development of heat
convection problems, are often
with a specification. The
heat transfer performance of the
the initial boundary conditions
of the problem, ranging from the initial charged temperature of
the water in the insulated tank of a fixed
dimensíon, to the
physical properties of the heat-exchanger's pipe. It was
concluded that an improvement in the heat transfer performance
can be derived by determining the optium length and the
orientation of the
heat-exchanger's arrangement. Further benefits
are derived by correlating the thermal convective behaviour,
within the hot-water store, with the forced passage of colder
water through the heat exchanger's pipe. A convective flow model,
based upon the experimental results, is described to advance the
heat
exchanger design principles in the situation of transient
natural convection. Assumptions employed in the experimental work
confirm that realistic and reasonable results can be obtained
from the thermal analysis of the vertical cylindrícal store in
two-dimensions.
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Lang, Hua 1963. "Advanced technologies for heat exchanger design and manufacturing." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10152.
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Salihu, Adamu Girei. "Optimal design and operation of heat exchanger network." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/9850.
Full textAbstract:
Heat exchanger networks (HENs) are the backbone of heat integration due to their ability in energy and environmental managements. This thesis deals with two issues on HENs. The first concerns with designing of economically optimal Heat exchanger network (HEN) whereas the second focus on optimal operation of HEN in the presence of uncertainties and disturbances within the network. In the first issue, a pinch technology based optimal HEN design is firstly implemented on a 3–streams heat recovery case study to design a simple HEN and then, a more complex HEN is designed for a coal-fired power plant retrofitted with CO2 capture unit to achieve the objectives of minimising energy penalty on the power plant due to its integration with the CO2 capture plant. The benchmark in this case study is a stream data from (Khalilpour and Abbas, 2011). Improvement to their work includes: (1) the use of economic data to evaluate achievable trade-offs between energy, capital and utility cost for determination of minimum temperature difference; (2) redesigning of the HEN based on the new minimum temperature difference and (3) its comparison with the base case design. The results shows that the energy burden imposed on the power plant with CO2 capture is significantly reduced through HEN leading to utility cost saving maximisation. The cost of addition of HEN is recoverable within a short payback period of about 2.8 years. In the second issue, optimal HEN operation considering range of uncertainties and disturbances in flowrates and inlet stream temperatures while minimizing utility consumption at constant target temperatures based on self-optimizing control (SOC) strategy. The new SOC method developed in this thesis is a data-driven SOC method which uses process data collected overtime during plant operation to select control variables (CVs). This is in contrast to the existing SOC strategies in which the CV selection requires process model to be linearized for nonlinear processes which leads to unaccounted losses due to linearization errors. The new approach selects CVs in which the necessary condition of optimality (NCO) is directly approximated by the CV through a single regression step. This work was inspired by Ye et al., (2013) regression based globally optimal CV selection with no model linearization and Ye et al., (2012) two steps regression based data-driven CV selection but with poor optimal results due to regression errors in the two steps procedures. The advantage of this work is that it doesn’t require evaluation of derivatives hence CVs can be evaluated even with commercial simulators such as HYSYS and UNISIM from among others. The effectiveness of the proposed method is again applied to the 3-streams HEN case study and also the HEN for coal-fired power plant with CO2 capture unit. The case studies show that the proposed methodology provides better optimal operation under uncertainties when compared to the existing model-based SOC techniques.
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Grady, Colin James. "Improved heat exchanger designs using vortex generators." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401336.
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Albrecht, Daniel David. "DESIGN AND CONSTRUCTION OF HEAT EXCHANGER TEST STAND WITH INITIAL TEST RESULTS." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/109.
Full textAbstract:
Continual development of internal combustion engines requires greater performance from liquid coolants and heat exchangers to maintain optimal temperature. For the purpose of experimental testing of traditional, compact, and microchannel heat exchangers, a test facility has been designed, constructed, and utilized. The facility includes equipment and instrumentation necessary to create operating conditions and record data primarily for testing plate-fin brazed aluminum heat exchanger where heat is being transferred from liquid to air. Other arrangements of heat exchangers could be tested as well with some modifications. Initial tests were performed at several specified operating conditions for three liquids: water, a traditional glycol based Extended Life Coolant (ELC), and a new Glycol Free Coolant (GFC) in an attempt to characterize their heat transfer ability. Results of the tests found that the product of overall heat transfer coefficient and heat exchanger area (UA) was very similar for GFC and water, and it was less for ELC by a narrow margin of 1.3% difference on average. Uncertainty due to instrumentation accuracy was calculated to be 1.8% on average making the results overall UA unverifiable. Measured pressure drop across the heat exchanger which is proportional to required pumping power was found to be 13.5% higher for GFC than ELC at nominal conditions. The GFC offers similar heat transfer performance and marginally increased pumping power requirements compared to the traditional ELC. Due to similar heat transfer performance and the small effect of pressure drop, GFC would be good alternative to ELC due to its less toxic composition.
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Perry, Jeffrey L. "Fouling in silicon microchannel designs used for IC chip cooling and its mitigation /." Online version of thesis, 2008. http://hdl.handle.net/1850/6211.
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