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Sample records for optimal heat exchanger

  1. Optimization of Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ivan Catton

    2010-10-01

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  2. Optimal design of the separate type heat pipe heat exchanger

    Institute of Scientific and Technical Information of China (English)

    YU Zi-tao; HU Ya-cai; CEN Ke-fa

    2005-01-01

    Separate type heat pipe heat exchangers are often used for large-scale heat exchanging. The arrangement of such a heat exchanger conveniently allows heat input to and output from the heat exchanger at remote locations. The traditional method of designing an ordinary HPHE (heat pipe heat exchanger) is commonly applied in the separate type exchanger design, but the calculations have to be carried out separately, which makes it very complicated. In this work, the ε-NTU (effectiveness-Number of Transfer Units) method was applied for optimization analysis of single- or multi-level separate type heat pipe heat exchangers. An optimizing formula for single-level separate type heat pipe heat exchangers was obtained. The optimizing principles of effectiveness-NTU and heat transfer rate by the equal distribution method for multi-level separate type heat pipe heat exchanger are presented. The design of separate type heat pipe heat exchangers by the optimizing method is more convenient and faster than by the traditional method.

  3. Optimization of Borehole Heat Exchanger Arrays

    Science.gov (United States)

    Schulte, Daniel; Rühaak, Wolfram; Welsch, Bastian; Oladyshkin, Sergey; Sass, Ingo

    2016-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storages for seasonally fluctuating heat sources like solar thermal energy or district heating grids. However, the uncertainty of geological parameters and the nonlinear behavior of the complex system make it difficult to simulate and predict the required design of borehole heat exchanger arrays. As a result, the arrays easily turn out to be over or undersized, which compromises the economic feasibility of these systems. Here, we present a novel optimization strategy for the design of borehole thermal energy storages. The arbitrary polynomial chaos expansion method is used to build a proxy model from a set of numerical training simulations, which allows for the consideration of parameter uncertainties. Thus, the resulting proxy model bypasses the problem of excessive computation time for the numerous function calls required for a mathematical optimization. Additionally, we iteratively refine the proxy model during the optimization procedure using additional numerical simulation runs. With the presented solution, many aspects of borehole heat exchanger arrays can be optimized under geological uncertainty.

  4. Heat exchanger design based on economic optimization

    Energy Technology Data Exchange (ETDEWEB)

    Caputo, Antonio C.; Pelagagge, Marcello P.; Salini, Paolo [University of l' Aquila (Italy). Faculty of Engineering], e-mail: caputo@ing.inivaq.it, e-mail: pelmar@ing.inivaq.it, e-mail: salini@ing.inivaq.it

    2006-07-01

    Owing to the wide utilization of heat exchangers in industrial processes their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which assume a configuration and gradually change design parameters until a satisfying solution is reached which meets the design specifications. However, such methods, besides being time consuming, do not guarantee the reach of an optimal solution. In this paper a procedure for optimal design for shell and tube heat exchangers is proposed which utilizes a genetic algorithm to minimize the total discounted cost of the equipment including the capital investment and pumping related annual energy expenditures. In order to verify the performances of the proposed method four case studies are also presented showing that total cost reductions greater than 15% are feasible respect traditionally designed exchangers. (author)

  5. Optimization of the Single Staggered Wire and Tube Heat Exchanger

    OpenAIRE

    Arsana I Made; Susianto; Budhikarjono Kusno; Altway Ali

    2016-01-01

    Wire and tube heat exchanger consists of a coiled tube, and wire is welded on the two sides of it in normal direction of the tube. Generally,wire and tube heat exchanger uses inline wire arrangement between the two sides, whereas in this study, it used staggered wire arrangement that reduces the restriction of convection heat transfer. This study performed the optimization of single staggered wire and tube heat exchanger to increase the capacity and reduce the mass of the heat exchanger. Opti...

  6. Optimization for entransy dissipation minimization in heat exchanger

    Institute of Scientific and Technical Information of China (English)

    XIA ShaoJun; CHEN LinGen; SUN FengRui

    2009-01-01

    A common of two-fluid flow heat exchanger, in which the heat transfer between high-and low-temperature sides obeys Newton's law [q∝△(T)], is studied in this paper. By taking entransy dissipation minimization as optimization objective, the optimum parameter distributions in the heat ex-changer are derived by using optimal control theory under the condition of fixed heat load. The condition corresponding to the minimum entransy dissipation is that corresponding to a constant heat flux density. Three kinds of heat exchangers, including parallel flow, condensing flow and counter-flow, are considered, and the results show that only the counter-flow heat exchanger can realize the entransy dissipation minimization in the heat transfer process. The obtained results for entransy dissipation minimization are also compared with those obtained for entropy generation minimization by numerical examples.

  7. Optimization of the Single Staggered Wire and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Arsana I Made

    2016-01-01

    Full Text Available Wire and tube heat exchanger consists of a coiled tube, and wire is welded on the two sides of it in normal direction of the tube. Generally,wire and tube heat exchanger uses inline wire arrangement between the two sides, whereas in this study, it used staggered wire arrangement that reduces the restriction of convection heat transfer. This study performed the optimization of single staggered wire and tube heat exchanger to increase the capacity and reduce the mass of the heat exchanger. Optimization was conducted with the Hooke-Jeeves method, which aims to optimize the geometry of the heat exchanger, especially on the diameter (dw and the distance between wires (pw. The model developed to present heat transfer correlations on single staggered wire and tube heat exchanger was valid. The maximum optimization factor obtained when the diameter wire was 0.9 mm and the distance between wires (pw was 11 mm with the fref value = 1.5837. It means that the optimized design only using mass of 59,10 % and could transfer heat about 98,5 % from the basis design.

  8. Optimization of Transient Heat Exchanger Performance for Improved Energy Efficiency

    Science.gov (United States)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Wirz, Richard

    2014-11-01

    Heat exchangers are used in a multitude of applications within systems for energy generation, energy conversion, or energy storage. Many of these systems (e.g. solar power plants) function under transient conditions, but the design of the heat exchangers is typically optimized assuming steady state conditions. There is a potential for significant energy savings if the transient behavior of the heat exchanger is taken into account in designing the heat exchanger by optimizing its operating conditions in relation to the transient behavior of the overall system. The physics of the transient behavior of a heat exchanger needs to be understood to provide design parameters for transient heat exchangers to deliver energy savings. A numerical model was used to determine the optimized mass flow rates thermal properties for a thermal energy storage system. The transient behavior is strongly linked to the dimensionless parameters relating fluid properties, the mass flow rates, and the temperature of the fluids at the inlet of each stream. Smart metals, or advanced heat exchanger surface geometries and methods of construction will be used to meet the three goals mentioned before: 1) energy and cost reduction, 2) size reduction, and 3) optimal performance for all modes of operation.

  9. An Alternative Algorithm for Optimal Design of Plate Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Seyyed Morteza Javid

    2015-02-01

    Full Text Available Due to the complex geometry of plate heat exchangers and thus a large number of variables affecting the performance of the exchangers, the design of these types of exchangers is quiet difficult. However, unlike the shell and tube heat exchangers which contain available data of design procedures, the design of plate heat exchanger is a monopoly of some certain manufacturing companies that make the problem even worse. In this paper, the objective is to minimize the number of plates in plate heat exchanger; in order to achieve that, a simple and yet efficient mathematical model is introduced for determination of the pressure drop and heat capacity of a plate heat exchanger in single- and multipass state and also a program was defined for determination of optimal solution based on this simple mathematical model for given operational constraints and plate type. In the end, the optimal solution will be compared to the answer of CAS200 commercial software and also it is shown that the effect of the start and end plates and transverse distribution in optimal solution is considerable.

  10. Optimization of Heat Exchangers for Intercooled Recuperated Aero Engines

    Directory of Open Access Journals (Sweden)

    Dimitrios Misirlis

    2017-03-01

    Full Text Available In the framework of the European research project LEMCOTEC, a section was devoted to the further optimization of the recuperation system of the Intercooled Recuperated Aero engine (IRA engine concept, of MTU Aero Engines AG. This concept is based on an advanced thermodynamic cycle combining both intercooling and recuperation. The present work is focused only on the recuperation process. This is carried out through a system of heat exchangers mounted inside the hot-gas exhaust nozzle, providing fuel economy and reduced pollutant emissions. The optimization of the recuperation system was performed using computational fluid dynamics (CFD computations, experimental measurements and thermodynamic cycle analysis for a wide range of engine operating conditions. A customized numerical tool was developed based on an advanced porosity model approach. The heat exchangers were modeled as porous media of predefined heat transfer and pressure loss behaviour and could also incorporate major and critical heat exchanger design decisions in the CFD computations. The optimization resulted in two completely new innovative heat exchanger concepts, named as CORN (COnical Recuperative Nozzle and STARTREC (STraight AnnulaR Thermal RECuperator, which provided significant benefits in terms of fuel consumption, pollutants emission and weight reduction compared to more conventional heat exchanger designs, thus proving that further optimization potential for this technology exists.

  11. Exergy optimization in a steady moving bed heat exchanger.

    Science.gov (United States)

    Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

    2009-04-01

    This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small.

  12. The computational optimization of heat exchange efficiency in stack chimneys

    Energy Technology Data Exchange (ETDEWEB)

    Van Goch, T.A.J.

    2012-02-15

    For many industrial processes, the chimney is the final step before hot fumes, with high thermal energy content, are discharged into the atmosphere. Tapping into this energy and utilizing it for heating or cooling applications, could improve sustainability, efficiency and/or reduce operational costs. Alternatively, an unused chimney, like the monumental chimney at the Eindhoven University of Technology, could serve as an 'energy channeler' once more; it can enhance free cooling by exploiting the stack effect. This study aims to identify design parameters that influence annual heat exchange in such stack chimney applications and optimize these parameters for specific scenarios to maximize the performance. Performance is defined by annual heat exchange, system efficiency and costs. The energy required for the water pump as compared to the energy exchanged, defines the system efficiency, which is expressed in an efficiency coefficient (EC). This study is an example of applying building performance simulation (BPS) tools for decision support in the early phase of the design process. In this study, BPS tools are used to provide design guidance, performance evaluation and optimization. A general method for optimization of simulation models will be studied, and applied in two case studies with different applications (heating/cooling), namely; (1) CERES case: 'Eindhoven University of Technology monumental stack chimney equipped with a heat exchanger, rejects heat to load the cold source of the aquifer system on the campus of the university and/or provides free cooling to the CERES building'; and (2) Industrial case: 'Heat exchanger in an industrial stack chimney, which recoups heat for use in e.g. absorption cooling'. The main research question, addressing the concerns of both cases, is expressed as follows: 'what is the optimal set of design parameters so heat exchange in stack chimneys is optimized annually for the cases in which a

  13. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    Science.gov (United States)

    Schulte, Daniel O.; Bastian, Welsch; Wolfram, Rühaak; Kristian, Bär; Ingo, Sass

    2017-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storage (BTES) systems for seasonally fluctuating heat sources like solar thermal energy or district heating grids. The high temperature level of these heat sources prohibits the use of the shallow subsurface for environmental reasons. Therefore, deeper reservoirs have to be accessed instead. The increased depth of the systems results in high investment costs and has hindered the implementation of this technology until now. Therefore, research of medium deep BTES systems relies on numerical simulation models. Current simulation tools cannot - or only to some extent - describe key features like partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We give an update on the development of BASIMO: a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport in a dual-continuum approach. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. Thereby, partly insulated boreholes can be considered in the model. Furthermore, BASIMO can be used to improve the design of BTES systems: the tool allows for automated parameter variations and is readily coupled to other code like mathematical optimization algorithms. Optimization can be used to determine the required minimum system size or to increase the system performance.

  14. Optimization of the Heat Exchangers of a Thermoelectric Generation System

    Science.gov (United States)

    Martínez, A.; Vián, J. G.; Astrain, D.; Rodríguez, A.; Berrio, I.

    2010-09-01

    The thermal resistances of the heat exchangers have a strong influence on the electric power produced by a thermoelectric generator. In this work, the heat exchangers of a thermoelectric generator have been optimized in order to maximize the electric power generated. This thermoelectric generator harnesses heat from the exhaust gas of a domestic gas boiler. Statistical design of experiments was used to assess the influence of five factors on both the electric power generated and the pressure drop in the chimney: height of the generator, number of modules per meter of generator height, length of the fins of the hot-side heat exchanger (HSHE), length of the gap between fins of the HSHE, and base thickness of the HSHE. The electric power has been calculated using a computational model, whereas Fluent computational fluid dynamics (CFD) has been used to obtain the thermal resistances of the heat exchangers and the pressure drop. Finally, the thermoelectric generator has been optimized, taking into account the restrictions on the pressure drop.

  15. Entropy generation extremum and entransy dissipation extremum for heat exchanger optimization

    Institute of Scientific and Technical Information of China (English)

    LIU XiongBin; MENG JiAn; GUO ZengYuan

    2009-01-01

    The applicability of the extremum principles of entropy generation and entransy dissipation is studied for heat exchanger optimization. The extremum principle of entransy dissipation gives better optimization results when heat exchanger is only for the purpose of heating and cooling, while the extremum principle of entropy generation is better for the heat exchanger optimization when it works in the Brayton cycle. The two optimization principles are approximately equivalent when the temperature drops of the streams in a heat exchanger are small.

  16. Development of optimization method for plate heat exchanger with undulation

    Directory of Open Access Journals (Sweden)

    Dvořák Václav

    2016-01-01

    Full Text Available The article deals with optimization of undulated heat transfer surface of plate heat exchanger. The goal of optimization is not only to increase effectiveness of heat transfer but also to reduce the pressure drop. A combined pattern of undulation which combines herringbone pattern and wavy pattern was optimized and best values of four parameters were found; angle of herringbone pattern, number, phase and amplitude of longitudinal waves of wavy pattern. The optimization procedure looked for maximum of objective function which was a linear combination of effectiveness and pressure drop. We used simple Monte Carlo method and the optimum was searched for four values of reference pressure drop. Four different optimization were run and we investigated the effect of various definition of objective function and parameters of undulation. It was found that during optimization of combined pattern, the herringbone pattern is more favoured than wavy pattern. It is caused by the fact that herringbone pattern was described by the only one free parameter, which was the angle of undulation, and therefore it is more likely to be found by a stochastic method. This assumption was confirmed when simple wavy pattern was optimized and higher values of objective function and effectiveness were found.

  17. Investigation and optimization of the depth of flue gas heat recovery in surface heat exchangers

    Science.gov (United States)

    Bespalov, V. V.; Bespalov, V. I.; Melnikov, D. V.

    2017-09-01

    Economic issues associated with designing deep flue gas heat recovery units for natural gas-fired boilers are examined. The governing parameter affecting the performance and cost of surface-type condensing heat recovery heat exchangers is the heat transfer surface area. When firing natural gas, the heat recovery depth depends on the flue gas temperature at the condenser outlet and determines the amount of condensed water vapor. The effect of the outlet flue gas temperature in a heat recovery heat exchanger on the additionally recovered heat power is studied. A correlation has been derived enabling one to determine the best heat recovery depth (or the final cooling temperature) maximizing the anticipated reduced annual profit of a power enterprise from implementation of energy-saving measures. Results of optimization are presented for a surface-type condensing gas-air plate heat recovery heat exchanger for the climatic conditions and the economic situation in Tomsk. The predictions demonstrate that it is economically feasible to design similar heat recovery heat exchangers for a flue gas outlet temperature of 10°C. In this case, the payback period for the investment in the heat recovery heat exchanger will be 1.5 years. The effect of various factors on the optimal outlet flue gas temperature was analyzed. Most climatic, economical, or technological factors have a minor effect on the best outlet temperature, which remains between 5 and 20°C when varying the affecting factors. The derived correlation enables us to preliminary estimate the outlet (final) flue gas temperature that should be used in designing the heat transfer surface of a heat recovery heat exchanger for a gas-fired boiler as applied to the specific climatic conditions.

  18. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    Science.gov (United States)

    Schulte, Daniel; Rühaak, Wolfram; Welsch, Bastian; Bär, Kristian; Sass, Ingo

    2016-04-01

    Borehole heat exchangers represent a well-established technology, which pushes for new fields of applications and novel modifications. Current simulation tools cannot - or only to some extent - describe features like inclined or partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We present a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. The presented tool benefits from the fast analytical solution of the thermal interactions within the boreholes while still allowing for a detailed consideration of the borehole heat exchanger properties.

  19. Handbook on heat exchangers

    Science.gov (United States)

    Bazhan, Pavel I.; Kanevets, Georgii E.; Seliverstov, Vladimir M.

    Essential data on heat exchange equipment used in ship, locomotive, automotive, and aircraft powerplants are presented in a systematic manner. The data cover the principal types and technical and performance characteristics of heat exchangers, fundamentals of the theory of heat exchange, calculation of heat transfer coefficients for different types of heat exchange apparatus, optimization of heat exchangers, computer-aided design of heat exchange equipment, testing techniques, and test result processing.

  20. Optimasi Desain Heat Exchanger dengan Menggunakan Metode Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Rifnaldi Veriyawan

    2014-09-01

    Full Text Available Industri proses terutama perminyakan adalah salah satu industri membutuhkan energi panas dengan jumlah kapasitas besar. Dengan berjalan perkembangan teknologi dibutuhkannya proses perpindahan panas dalam jumlah besar. Tetapi dengan besarnya penukaran panas yang diberikan maka besar pula luas permukaan. Dibutuhkannya optimasi pada desain heat exchanger terutama shell-and-tube¬. Dalam tugas akhir ini, Algoritma particle swarm optimization (PSO digunakan untuk mengoptimasikan nilai koefesien perpindahan panas keseluruhan dengan mendapatkan nilai terbaik. Perumusan fungsi tujuan nilai perpindahan panas keseluruhan (U, dan luas permukaan (A yang digunakan untuk mencari nilai fungsi objektif pada PSO. Partikel dalam PSO menyatakan sebagai posisi atau solusi dari hasil optimasi didapatnya nilai perpindahan panas maksimal dengan luas permukaan dan pressure drop dibawah data desain atau datasheet. Partikel tersebut dalam pemodelan berupa rentang nilai minimal dan maksimal dari diameter luar diantara (do dan jumlah baffle (Nb. Dari hasil optimasi pada tiga HE didapatkan nilai U dan A secara berturut-turut; HE E-1111 472 W/m2C dan 289 m2 ;pada HE E-1107 174 W/m2C dan 265 m2 ; dan HE E-1102 618 W/m2C dan 574 m2. Nilai perpindahan panas keseluruhan yang telah dioptimasi sesuai dengan fungsi objektif dapat dikatakan HE shell-and-tube mencapai titik optimal.

  1. Design and economic optimization of shell and tube heat exchangers using Artificial Bee Colony (ABC) algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Sencan Sahin, Arzu, E-mail: sencan@tef.sdu.edu.tr [Department of Mechanical Education, Technical Education Faculty, Sueleyman Demirel University, 32260 Isparta (Turkey); Kilic, Bayram, E-mail: bayramkilic@hotmail.com [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey); Kilic, Ulas, E-mail: ulaskilic@mehmetakif.edu.tr [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey)

    2011-10-15

    Highlights: {yields} Artificial Bee Colony for shell and tube heat exchanger optimization is used. {yields} The total cost is minimized by varying design variables. {yields} This new approach can be applied for optimization of heat exchangers. - Abstract: In this study, a new shell and tube heat exchanger optimization design approach is developed. Artificial Bee Colony (ABC) has been applied to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping of shell and tube heat exchanger by varying various design variables such as tube length, tube outer diameter, pitch size, baffle spacing, etc. Finally, the results are compared to those obtained by literature approaches. The obtained results indicate that Artificial Bee Colony (ABC) algorithm can be successfully applied for optimal design of shell and tube heat exchangers.

  2. Heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Craig, L.B.; Farma, A.J.

    1987-01-06

    This invention concerns a heat exchanger as used in a space heater, of the type in which hot exhaust gases transfer heat to water or the like flowing through a helical heat exchange coil. A significant improvement to the efficiency of the heat exchange occurring between the air and water is achieved by using a conduit for the water having external helical fluting such that the hot gases circulate along two paths, rather than only one. A preferred embodiment of such a heat exchanger includes a porous combustion element for producing radiant heat from a combustible gas, surrounded by a helical coil for effectively transferring the heat in the exhaust gas, flowing radially from the combustion element, to the water flowing through the coil. 4 figs.

  3. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    2004-01-01

    Proton Exchange Membrane (PEM) based combined heat and power production systems are highly integrated energy systems. They may include a hydrogen production system and fuel cell stacks along with post combustion units optionally coupled with gas turbines. The considered system is based on a natural...... steam reforming reaction and steam must be generated. The dependence of the temperature profiles on conversion in shift reactors for gas purification is also significant. The optimum heat integration in the system is thus imperative in order to minimize the need for hot and cold utilities. A rigorous 1D...... gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...

  4. HECDOR: a heat exchanger cost and design optimization routine

    Energy Technology Data Exchange (ETDEWEB)

    Turner, S.E.; Madsen, W.W.

    1977-04-01

    An update is presented on a series of four computer codes developed by the Bureau of Mines. The programs were developed to evaluate design parameters and cost of heat exchangers. The major differences in three of the programs were concerned with pumping costs; the first (N = 1) used both fluids, the second (N = 2) used tube side fluid, and the third (N = 3) used shell side fluid as a base for prime parameters. All three assumed no change in phase. The fourth program (N = 4) assumed a change of phase on the shell side.

  5. Use of Algorithm of Changes for Optimal Design of Heat Exchanger

    Science.gov (United States)

    Tam, S. C.; Tam, H. K.; Chio, C. H.; Tam, L. M.

    2010-05-01

    For economic reasons, the optimal design of heat exchanger is required. Design of heat exchanger is usually based on the iterative process. The design conditions, equipment geometries, the heat transfer and friction factor correlations are totally involved in the process. Using the traditional iterative method, many trials are needed for satisfying the compromise between the heat exchange performance and the cost consideration. The process is cumbersome and the optimal design is often depending on the design engineer's experience. Therefore, in the recent studies, many researchers, reviewed in [1], applied the genetic algorithm (GA) [2] for designing the heat exchanger. The results outperformed the traditional method. In this study, the alternative approach, algorithm of changes, is proposed for optimal design of shell-tube heat exchanger [3]. This new method, algorithm of changes based on I Ching (???), is developed originality by the author. In the algorithms, the hexagram operations in I Ching has been generalized to binary string case and the iterative procedure which imitates the I Ching inference is also defined. On the basis of [3], the shell inside diameter, tube outside diameter, and baffles spacing were treated as the design (or optimized) variables. The cost of the heat exchanger was arranged as the objective function. Through the case study, the results show that the algorithm of changes is comparable to the GA method. Both of method can find the optimal solution in a short time. However, without interchanging information between binary strings, the algorithm of changes has advantage on parallel computation over GA.

  6. Simulation and Optimization of the Heat Exchanger for Automotive Exhaust-Based Thermoelectric Generators

    Science.gov (United States)

    Su, C. Q.; Huang, C.; Deng, Y. D.; Wang, Y. P.; Chu, P. Q.; Zheng, S. J.

    2016-03-01

    In order to enhance the exhaust waste heat recovery efficiency of the automotive exhaust-based thermoelectric generator (TEG) system, a three-segment heat exchanger with folded-shaped internal structure for the TEG system is investigated in this study. As the major effect factors of the performance for the TEG system, surface temperature, and thermal uniformity of the heat exchanger are analyzed in this research, pressure drop along the heat exchanger is also considered. Based on computational fluid dynamics simulations and temperature distribution, the pressure drop along the heat exchanger is obtained. By considering variable length and thickness of folded plates in each segment of the heat exchanger, response surface methodology and optimization by a multi-objective genetic algorithm is applied for surface temperature, thermal uniformity, and pressure drop for the folded-shaped heat exchanger. An optimum design based on the optimization is proposed to improve the overall performance of the TEG system. The performance of the optimized heat exchanger in different engine conditions is discussed.

  7. Estimation and optimization of heat transfer and overall presure drop for a shell and tube heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Bala Bhaskara [Dept. of Mechanical Engineering, SISTAM College, JNTU, Kakinada (India); Raju, V. Ramachandra [Dept. of Mechanical Engineering, JNTU, Kakinada (India); Deepak, B. B V. L. [Dept. of Industrial Design, National Institute of Technology, Rourkela (India)

    2017-01-15

    Most thermal/chemical industries are equipped with heat exchangers to enhance thermal efficiency. The performance of heat exchangers highly depends on design modifications in the tube side, such as the cross-sectional area, orientation, and baffle cut of the tube. However, these parameters do not exhibit a specific relation to determining the optimum design condition for shell and tube heat exchangers with a maximum heat transfer rate and reduced pressure drops. Accordingly, experimental and numerical simulations are performed for a heat exchanger with varying tube geometries. The heat exchanger considered in this investigation is a single-shell, multiple-pass device. A Generalized regression neural network (GRNN) is applied to generate a relation among the input and output process parameters for the experimental data sets. Then, an Artificial immune system (AIS) is used with GRNN to obtain optimized input parameters. Lastly, results are presented for the developed hybrid GRNN-AIS approach.

  8. Thermoelectric generator sandwiched in a crossflow heat exchanger with optimal connectivity between modules

    Energy Technology Data Exchange (ETDEWEB)

    Belanger, Simon [Departement de genie mecanique, Universite Laval, 1065, avenue de la Medecine, Quebec City, QC, G1V 0A6 (Canada); Gosselin, Louis, E-mail: Louis.Gosselin@gmc.ulaval.ca [Departement de genie mecanique, Universite Laval, 1065, avenue de la Medecine, Quebec City, QC, G1V 0A6 (Canada)

    2011-08-15

    Highlights: {yields} In this paper, we propose a numerical model for a crossflow heat exchanger with a thermoelectric generator sandwiched in its wall. {yields} The number of thermoelectric modules and the electrical connections between them is optimized with a genetic algorithm. {yields} Complex electric current topologies are achieved in order to maximize the total power output. - Abstract: The design of a thermoelectric generator sandwiched in the wall of a crossflow heat exchanger was optimized. A numerical model has been developed and validated. The objective function was the total power output. The design variables were the number of modules and the current in each control volume of the mesh. We also optimize directly the electrical topology of the system. A genetic algorithm was used to perform the optimizations. Complex optimal electrical topologies were achieved due to the non-uniform temperatures distributions in the heat exchanger.

  9. Co-optimized design of microchannel heat exchangers and thermoelectric generators

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Yazawa, K.; Rosendahl, Lasse;

    2013-01-01

    Designs of heat exchangers have mostly been disconnected to the performance of thermoelectric generator (TEG) systems. The development work, mostly focused on thermoelectric materials, required a significant amount of engineering parametric analysis. In this work, a micro plate-fin heat exchanger...... applied to a TEG is investigated and optimized to maximize the output power and the cost performance of generic TEG systems. The cost per performance is counted by a measure of price per power output ($/W). The channel width, channel height, fin thickness of heat exchanger, and fill factor of TEG...... are theoretically optimized for a wide range of pumping power. In conjunction with effective numeric tests, the model discusses the optimum size of the system components’ dimensions at two area sizes of the substrate plate of heat exchanger. Results show that at every pumping power, there are particular values...

  10. A Fully Developed Flow Thermofluid Model for Topology Optimization of 3D-Printed Air-Cooled Heat Exchangers

    DEFF Research Database (Denmark)

    Haertel, Jan Hendrik Klaas; Nellis, Gregory F.

    2017-01-01

    . The conductance of the heat exchanger is maximized for a prescribed pressure drop and prescribed air-side temperature change across the heat exchanger. Polymer with infilled thermally conducting metal filaments is considered as the heat exchanger material which allows cost effective additive manufacturing...... optimized slot channel model in order to demonstrate the superior performance of the topology optimized designs. Thus, this work demonstrates the usefulness of topology optimization to fully exploit the design freedom afforded by additive manufacturing technologies....

  11. Modeling and Optimization for Heat Exchanger Networks Synthesis Based on Expert System and Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    LIZhihong

    2002-01-01

    A new superstructure from of heat exchanger networks(HEN) is proposed based on expert system (ES). The new superstructure from is combined with the practical engineering.The different investment cost formula for different heat exchanger is also presented based on ES.The mathematical model for the simultaneous optimization of network configuration is established and solved by a genetic algorithm.This method can deal with larger scale HEN synthesis and the optimal HEN configuration is obtained automatically.Finally,a case study is presented to demonstrate the effectiveness of the method.

  12. Optimization principle of operating parameters of heat exchanger by using CFD simulation

    Science.gov (United States)

    Mičieta, Jozef; Jiří, Vondál; Jandačka, Jozef; Lenhard, Richard

    2016-03-01

    Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation.

  13. Optimization principle of operating parameters of heat exchanger by using CFD simulation

    Directory of Open Access Journals (Sweden)

    Mičieta Jozef

    2016-01-01

    Full Text Available Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation.

  14. Multi-objective optimization of a plain fin-and-tube heat exchanger using genetic algorithm

    Science.gov (United States)

    Juan, Du; Qin, Qian Zuo

    2014-04-01

    In the present paper, a plate fin-and-tube heat exchanger (PFTHE) is considered for optimization with air and water as working fluid, four geometric variables are taken as parameters for optimization, a Genetic Algorithm (GA) was used to search for the optimal structure sizes of the PFTHE, the maximum total heat transfer rate and the minimum total pressure drop are taken as objective functions in GA, respectively. Performance of the optimized result was evaluated and correspondingly the total heat transfer rate, the total pressure drop, the heat transfer coefficient and the local Nusselt number, j-factor and friction factor ξ are calculated respectively. Results show that the total heat transfer rate of the optimized heat exchanger increased by about 2.1-9.2% comparing with the original one, the heat transfer coefficient increased by about 8.2-14.7% and the total pressure drop decreased by about 4.4-8% in the range of Re = 1200-14000.

  15. Optimal Design of Multistage Two-Dimensional Cellular-Cored Sandwich Panel Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Yongcun Zhang

    2014-08-01

    Full Text Available For a two-dimensional (2D cellular-cored sandwich panel heat exchanger, there exists an optimum cell size to achieve the maximum heat transfer with the prescribed pressure drop when the length is fixed and the two plates are isothermal. However, in engineering design, it is difficult to find 2D cellular materials with the ideal cell size because the cell size selected must be from those commercially available, which are discrete, not continuous. In order to obtain the maximum heat dissipation, an innovative design scheme is proposed for the sandwich panel heat exchanger which is divided into multiple stages in the direction of fluid flow where the 2D cellular material in each stage has a specific cell size. An analytical model is presented to evaluate the thermal performance of the multistage sandwich panel heat exchanger when all 2D cellular materials have the same porosity. Also, a new parameter named equivalent cell size (ECS is defined, which is dependent on the cell size and length of cellular material in all stages. Results show that the maximum heat dissipation design of the multistage sandwich panel heat exchanger can be converted to make the ECS equal to the optimal cell size of the single-stage exchanger.

  16. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    2004-01-01

    gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...... steam reforming reaction and steam must be generated. The dependence of the temperature profiles on conversion in shift reactors for gas purification is also significant. The optimum heat integration in the system is thus imperative in order to minimize the need for hot and cold utilities. A rigorous 1D...

  17. A screening method for the optimal selection of plate heat exchanger configurations

    Directory of Open Access Journals (Sweden)

    Pinto J.M.

    2002-01-01

    Full Text Available An optimization method for determining the best configuration(s of gasketed plate heat exchangers is presented. The objective is to select the configuration(s with the minimum heat transfer area that still satisfies constraints on the number of channels, the pressure drop of both fluids, the channel flow velocities and the exchanger thermal effectiveness. The configuration of the exchanger is defined by six parameters, which are as follows: the number of channels, the numbers of passes on each side, the fluid locations, the feed positions and the type of flow in the channels. The resulting configuration optimization problem is formulated as the minimization of the exchanger heat transfer area and a screening procedure is proposed for its solution. In this procedure, subsets of constraints are successively applied to eliminate infeasible and nonoptimal solutions. Examples show that the optimization method is able to successfully determine a set of optimal configurations with a minimum number of exchanger evaluations. Approximately 5 % of the pressure drop and channel velocity calculations and 1 % of the thermal simulations are required for the solution.

  18. Performing multiobjective optimization on perforated plate matrix heat exchanger surfaces using genetic algorithm

    Directory of Open Access Journals (Sweden)

    John Anish K.

    2017-01-01

    Full Text Available Matrix Heat Exchanger is having wide spread applications in cryogenics and aerospace, where high effectiveness and compactness is essential. This can be achieved by providing high thermal conductive plates and low thermal conductive spacers alternately. These perforated plate matrix heat exchangers have near to 100% efficiency due to low longitudinal heat transfer. The heat transfer and flow friction characteristics of a perforated plate matrix heat exchanger can be represented using Colburn factor and friction factor. In this paper, dimensionless parameters like Reynolds number (Re, porosity (p, perforation perimeter factor (P f, plate thickness to pore diameter ratio (l/d and spacer thickness to plate thickness ratio (s/l have been optimized for maximum Colburn factor and minimum friction factor using genetic algorithm. Two algorithms, one for single objective and the other for multi-objective problems, which are believed to be more efficient, are described. The algorithms coded with MATLAB, is used to perform multi-objective optimization on perforated plate matrix heat exchanger surfaces. The results show promising results.

  19. Application of optimization for improvement of the efficiency of louvered-fin compact heat exchangers

    Directory of Open Access Journals (Sweden)

    Diego Amorim Caetano Souza

    Full Text Available Abstract A few decades ago, the product development process was just based on a trial and error procedure, and the designer's experience. The need for a new way to design and manufacture more economical and sustainable products corroborates increasingly to a new vision of how to create new products for the benefit of society. Modern numerical tools allow greater knowledge about the physical phenomena involved in engineering problems and enable cost reduction with trials and time of manufacture and projection. Among the equipment that can be mentioned where numerical simulation is used, can be found heat exchangers, which are capable of accomplishing the heat transfer between two fluid medias with different temperatures. Within the range of existing exchangers, this work will address a compact model with louvered fins, widely used in the automotive and aerospace industries, mainly due to their high thermal exchange surface vs occupied volume ratio. The heat exchanger surface is analised using computational fluid dynamics tecniques disposable in the commercial code ANSYS CFX14® to reproduce the flow at service condition. Genetic optimization routines are used to increase the performance of heat exchanger. As a result, a heat transfer surface is obtained with about a 25% better performance according to the selected objective function. The dimensionless factor of the convective heat transfer coefficient (Colburn factor, j and the friction factor (Fanning factor, f used in (Wang et al.,1998, are employed for simulation. Experimental data are also used for validation.

  20. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  1. Thermal-economic multi-objective optimization of shell and tube heat exchanger using particle swarm optimization (PSO)

    Science.gov (United States)

    Ghanei, A.; Assareh, E.; Biglari, M.; Ghanbarzadeh, A.; Noghrehabadi, A. R.

    2014-10-01

    Many studies are performed by researchers about shell and tube heat exchanger (STHE) but the multi-objective particle swarm optimization (PSO) technique has never been used in such studies. This paper presents application of thermal-economic multi-objective optimization of STHE using PSO. For optimal design of a STHE, it was first thermally modeled using e-number of transfer units method while Bell-Delaware procedure was applied to estimate its shell side heat transfer coefficient and pressure drop. Multi objective PSO (MOPSO) method was applied to obtain the maximum effectiveness (heat recovery) and the minimum total cost as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called `Pareto optimal solutions'. In order to show the accuracy of the algorithm, a comparison is made with the non-dominated sorting genetic algorithm (NSGA-II) and MOPSO which are developed for the same problem.

  2. Thermal-economic multi-objective optimization of plate fin heat exchanger using genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Hajabdollahi, Hassan [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST) (Iran)

    2010-06-15

    Thermal modeling and optimal design of compact heat exchangers are presented in this paper. {epsilon}NTU method was applied to estimate the heat exchanger pressure drop and effectiveness. Fin pitch, fin height, fin offset length, cold stream flow length, no-flow length and hot stream flow length were considered as six design parameters. Fast and elitist non-dominated sorting genetic-algorithm (NSGA-II) was applied to obtain the maximum effectiveness and the minimum total annual cost (sum of investment and operation costs) as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called 'Pareto optimal solutions'. The sensitivity analysis of change in optimum effectiveness and total annual cost with change in design parameters of the plate fin heat exchanger was also performed and the results are reported. As a short cut for choosing the system optimal design parameters the correlations between two objectives and six decision variables with acceptable precision were presented using artificial neural network analysis. (author)

  3. Thermodynamic optimization of geometric structure in the counterflow heat exchanger for an environmental control system

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, T. [Osaka Prefecture Univ., Dept. of Energy Systems Engineering, Sakai, Osaka (Japan); Bejan, A. [Duke Univ., Dept. of Mechanical Engineering and Materials Science, Durham, NC (United States)

    2001-05-01

    This paper shows that the internal geometric configuration of a component can be deduced by optimising the global performance of the installation that uses the component. The example chosen is the counterflow heat exchanger that serves as condenser in a vapor-compression-cycle refrigeration system for environmental control of aircraft. The optimisation of global performance is achieved by minimising the total power requirement or the total entropy generation rate. There are three degrees of freedom in the heat exchanger configuration, which is subjected to two global constraints: total volume, and total volume (or weight) of wall-material. Numerical results show how the optimal configuration responds to changes in specified external parameters such as refrigeration load, fan efficiency, and volume and weight. In accordance with constructal theory and design, it is shown that the optimal configuration is robust: major features such as the ratio of diameters and the flow length are relatively insensitive to changes in the external parameters. (Author)

  4. Multi-objective optimization of a plate and frame heat exchanger via genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Najafi, Hamidreza; Najafi, Behzad [K. N. Toosi University of Technology, Department of Mechanical Engineering, Tehran (Iran)

    2010-06-15

    In the present paper, a plate and frame heat exchanger is considered. Multi-objective optimization using genetic algorithm is developed in order to obtain a set of geometric design parameters, which lead to minimum pressure drop and the maximum overall heat transfer coefficient. Vividly, considered objective functions are conflicting and no single solution can satisfy both objectives simultaneously. Multi-objective optimization procedure yields a set of optimal solutions, called Pareto front, each of which is a trade-off between objectives and can be selected by the user, regarding the application and the project's limits. The presented work takes care of numerous geometric parameters in the presence of logical constraints. A sensitivity analysis is also carried out to study the effects of different geometric parameters on the considered objective functions. Modeling the system and implementing the multi-objective optimization via genetic algorithm has been performed by MATLAB. (orig.)

  5. Robust multi-objective optimization of state feedback controllers for heat exchanger system with probabilistic uncertainty

    Science.gov (United States)

    Lotfi, Babak; Wang, Qiuwang

    2013-07-01

    The performance of thermal control systems has, in recent years, improved in numerous ways due to developments in control theory and information technology. The shell-and-tube heat exchanger (STHX) is a medium where heat transfer process occurred. The accuracy of the heat exchanger depends on the performance of both elements. Therefore, both components need to be controlled in order to achieve a substantial result in the process. For this purpose, the actual dynamics of both shell and tube of the heat exchanger is crucial. In this paper, optimal reliability-based multi-objective Pareto design of robust state feedback controllers for a STHX having parameters with probabilistic uncertainties. Accordingly, the probabilities of failure of those objective functions are also considered in the reliability-based design optimization (RBDO) approach. A new multi-objective uniform-diversity genetic algorithm (MUGA) is presented and used for Pareto optimum design of linear state feedback controllers for STHX problem. In this way, Pareto front of optimum controllers is first obtained for the nominal deterministic STHX using the conflicting objective functions in time domain. Such Pareto front is then obtained for STHX having probabilistic uncertainties in its parameters using the statistical moments of those objective functions through a Hammersley Sequence Sampling (HSS) approach. It is shown that multi-objective reliability-based Pareto optimization of the robust state feedback controllers using MUGA includes those that may be obtained by various crisp threshold values of probability of failures and, thus, remove the difficulty of selecting suitable crisp values. Besides, the multi-objective Pareto optimization of such robust feedback controllers using MUGA unveils some very important and informative trade-offs among those objective functions. Consequently, some optimum robust state feedback controllers can be compromisingly chosen from the Pareto frontiers.

  6. 3D numerical simulation and structural optimization of the rod baffle heat exchanger

    Institute of Scientific and Technical Information of China (English)

    YAN Liang-wen; PAN Lei; KAN Shu-lin

    2009-01-01

    Because of the complexities of fluid dynamics equations and the structure of heat exchangers, few theoretical solutions have been acquired to specify the shell side characteristics of the rod baffle heat exchanger (RBHE). Based on the platform of PHEONICS version 3.5.1, a three-dimensionai numerical method for predicting the turbulent fluid flow behavior in the shell side of the rod baffle heat exchangers is developed in this paper. With this method, modeling of the tube bundle is carried out based on the porous media concept using volumetric porosities and applicable flow resistance correlations. Turbulence effects are modeled using a standard κ-ε model. It is shown that the simulation results and experimental results are in good agreement in the shell side. The maximum absolute deviation value of pressure drops is less than 5%, and that of the heat transfer coefficients is less than 8%. Furthermore, the numerical model is used to optimize the structure of the RBHE and improves its performance.

  7. Numerical optimization of louvered fin heat exchanger with variable louver angles

    Science.gov (United States)

    Ameel, B.; Degroote, J.; Huisseune, H.; De Jaeger, P.; Vierendeels, J.; De Paepe, M.

    2012-11-01

    Several studies of the louvered fin heat exchanger have already been done. Both experimental and numerical studies are available. Investigations to the optimal louver angle have been performed, many times in combination with other fin parameters such as louver pitch and fin thickness. Most studies assume a single louver angle for all the louvers in the heat exchanger. Hsieh and Jang [1] on the other hand studied the effect of a variable louver angle for 5 different cases with successively increasing or decreasing louver angles. Tube-fin interactions were not taken into account. In this study, a round tube and fin geometry with individually varying louver angles is analyzed. The thickness of the fin was neglected. Any interactions between the optimal louver angles and the fin thickness are hence not captured. A laminar and steady calculation was performed, with symmetric boundary conditions. For the Reynolds number on the hydraulic diameter (ReDh) of 535 that was studied, a Von Karman vortex street is present behind the last tube row of heat exchanger. The steady calculation is hence only an approximation of the reality, but is shown to give reasonable results. An ordinary kriging response surface model was used to explore the entire parameter space. Updates to the model were made on the basis of improving the Pareto front, visualizing the tradeoff between heat transfer and pressure drop. It is shown that the use of individually varying louver angles allows increasing the Colburn j factor by 1.3% for the same friction factor, with respect to the optimal uniform louvered fin configuration.

  8. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Heidar Sadeghzadeh

    2015-08-01

    Full Text Available Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The “Delaware modified” technique is used to determine heat transfer coefficients and the shell-side pressure drop. In this technique, the baffle cut is 20 percent and the baffle ratio limits range from 0.2 to 0.4. The optimization of the objective functions (maximum heat transfer rate and minimum total cost is performed using a non-dominated sorting genetic algorithm (NSGA-II, and compared against a one-objective algorithm, to find the best solutions. The results are depicted as a set of solutions on a Pareto front, and show that the heat transfer rate ranges from 3517 to 7075 kW. Also, the minimum and maximum objective functions are specified, allowing the designer to select the best points among these solutions based on requirements. Additionally, variations of shell-side pressure drop with total cost are depicted, and indicate that the pressure drop ranges from 3.8 to 46.7 kPa.

  9. Thermal-economic multiobjective optimization of heat pipe heat exchanger for energy recovery in HVAC applications using genetic algorithm

    Directory of Open Access Journals (Sweden)

    Sanaye Sepehr

    2014-01-01

    Full Text Available Cost and effectiveness are two important factors of heat pipe heat exchanger (HPHE design. The total cost includes the investment cost for buying equipment (heat exchanger surface area and operating cost for energy expenditures (related to fan power. The HPHE was thermally modeled using e-NTU method to estimate the overall heat transfer coefficient for the bank of finned tubes as well as estimating pressure drop. Fast and elitist non-dominated sorting genetic algorithm (NSGA-II with continuous and discrete variables was applied to obtain the maximum effectiveness and the minimum total cost as two objective functions. Pipe diameter, pipe length, numbers of pipes per row, number of rows, fin pitch and fin length ratio were considered as six design parameters. The results of optimal designs were a set of multiple optimum solutions, called ‘Pareto optimal solutions’. The comparison of the optimum values of total cost and effectiveness, variation of optimum values of design parameters as well as estimating the payback period were also reported for various inlet fresh air volume flow rates.

  10. Performance evaluation and parametric optimization of a proton exchange membrane fuel cell/heat-driven heat pump hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Chen, J. [Department of Physics, Xiamen University, Xiamen 361005 (China)

    2012-06-15

    With the help of the current models of proton exchange membrane (PEM) fuel cells and three-heat-source heat pumps, a generic model of a PEM fuel cell/heat-driven heat pump hybrid system is established, so that the waste heat produced in the PEM fuel cell may be availably utilized. Based on the theory of electrochemistry and non-equilibrium thermodynamics, expressions for the efficiency and power output of the PEM fuel cell, the coefficient of performance and rate of pumping heat of the heat-driven heat pump, and the equivalent efficiency and power output of the hybrid system are derived. The curves of the equivalent efficiency and power output of the hybrid system varying with the electric current density and the equivalent power output versus efficiency curves are represented through numerical calculation. The general performance characteristics of the hybrid system are analyzed. The optimally operating regions of some important parameters of the hybrid system are determined. The influence of some main irreversible losses on the performance of the hybrid system is discussed in detail. The advantages of the hybrid system are revealed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Optimization of counterflow heat exchanger geometry through minimization of entropy generation

    NARCIS (Netherlands)

    Lerou, P.P.P.M.; Veenstra, T.T.; Burger, J.F.; Brake, ter H.J.M.; Rogalla, H.

    2005-01-01

    A counterflow heat exchanger (CFHX) is an essential element for recuperative cooling cycles. The performance of the CFHX strongly influences the overall performance of the cryocooler. In the design of a heat exchanger, different loss mechanisms like pressure drop and parasitic heat flows are often t

  12. A new optimization approach for shell and tube heat exchangers by using electromagnetism-like algorithm (EM)

    Science.gov (United States)

    Abed, Azher M.; Abed, Issa Ahmed; Majdi, Hasan Sh.; Al-Shamani, Ali Najah; Sopian, K.

    2016-12-01

    This study proposes a new procedure for optimal design of shell and tube heat exchangers. The electromagnetism-like algorithm is applied to save on heat exchanger capital cost and designing a compact, high performance heat exchanger with effective use of the allowable pressure drop (cost of the pump). An optimization algorithm is then utilized to determine the optimal values of both geometric design parameters and maximum allowable pressure drop by pursuing the minimization of a total cost function. A computer code is developed for the optimal shell and tube heat exchangers. Different test cases are solved to demonstrate the effectiveness and ability of the proposed algorithm. Results are also compared with those obtained by other approaches available in the literature. The comparisons indicate that a proposed design procedure can be successfully applied in the optimal design of shell and tube heat exchangers. In particular, in the examined cases a reduction of total costs up to 30, 29, and 56.15 % compared with the original design and up to 18, 5.5 and 7.4 % compared with other approaches for case study 1, 2 and 3 respectively, are observed. In this work, economic optimization resulting from the proposed design procedure are relevant especially when the size/volume is critical for high performance and compact unit, moderate volume and cost are needed.

  13. OPTIMIZATION OF INTERNAL HEAT EXCHANGERS FOR HYDROGEN STORAGE TANKS UTILIZING METAL HYDRIDES

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, S.; Tamburello, D.; Hardy, B.; Anton, D.; Gorbounov, M.; Cognale, C.; van Hassel, B.; Mosher, D.

    2011-07-14

    Two detailed, unit-cell models, a transverse fin design and a longitudinal fin design, of a combined hydride bed and heat exchanger are developed in COMSOL{reg_sign} Multiphysics incorporating and accounting for heat transfer and reaction kinetic limitations. MatLab{reg_sign} scripts for autonomous model generation are developed and incorporated into (1) a grid-based and (2) a systematic optimization routine based on the Nelder-Mead downhill simplex method to determine the geometrical parameters that lead to the optimal structure for each fin design that maximizes the hydrogen stored within the hydride. The optimal designs for both the transverse and longitudinal fin designs point toward closely-spaced, small cooling fluid tubes. Under the hydrogen feed conditions studied (50 bar), a 25 times improvement or better in the hydrogen storage kinetics will be required to simultaneously meet the Department of Energy technical targets for gravimetric capacity and fill time. These models and methodology can be rapidly applied to other hydrogen storage materials, such as other metal hydrides or to cryoadsorbents, in future work.

  14. Optimization of an industrial retrofitted heat exchanger network, using a stage-wise model

    Energy Technology Data Exchange (ETDEWEB)

    Kovac Kralj, Anita [Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, Maribor 2000 (Slovenia)

    2010-12-15

    The heat exchanger network (HEN) can be optimized using the stage-wise model of superstructure representation, as proposed by Yee and Grossmann. This model can be easily solved regarding both trivial problems, and serious and complex new industrial design plants. In this paper, a stage-wise model for new designs is extended for retrofits by using a stage-wise model for a retrofitted HEN. This method using a stage-wise model is very general; it can be used in new designs as well as during existing process integration. The methodology of the stage-wise model for retrofitted HEN can be used to solve HENs easily and well enough, over a short time, and simultaneously. A mathematical model of stage-wise for retrofit HEN can include additional equations and limitations for retrofits. This model was tested by using a retrofitted methanol process generating an additional profit of 189,200 EUR/a. (author)

  15. Temperature Approach Optimization in the Double Pipe Heat Exchanger with Groove

    Directory of Open Access Journals (Sweden)

    Sunu Putu Wijaya

    2016-01-01

    Full Text Available Heat transfer in double pipe heat exchanger with circumference-rectangular grooves has been investigated experimentally. The volume flowrate of cold and hot water were varied to determine its influence on the approach temperature of the outlet terminals. In this experimental design, the grooves were incised in annular room that is placed on the outside surface of the inner pipe. The shell diameter is 38.1 mm and tube diameter 19.4 mm with 1 m length, which is made of aluminum. The flow pattern of the two fluids in the heat exchanger is a parallel flow. The working fluid is water with volume flow rate of 27.1, 23.8 and 19.8 l/minute. The temperature of water on the inlet terminals are 50±1°C for hot stream and 30±1°C for cold stream. Temperature measurements conducted on each terminal of the inlet and outlet heat exchanger. The results showed that the grooves induced the approach temperature. The change of the approach temperature from the grooves compared to that of without grooves decreased by 37.9%. This phenomenon indicates an increase in heat transfer process and performance of the heat exchanger. Groove improves the heat surface area of the inner pipe, increasing the momentum transfer and in the other hand, reducing the weight of heat exchangers itself.

  16. Optimized heat exchange in a CO2 de-sublimation process

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Larry; Terrien, Paul; Tessier, Pascal; Hoeger, Christopher

    2017-09-19

    The present invention is a process for removing carbon dioxide from a compressed gas stream including cooling the compressed gas in a first heat exchanger, introducing the cooled gas into a de-sublimating heat exchanger, thereby producing a first solid carbon dioxide stream and a first carbon dioxide poor gas stream, expanding the carbon dioxide poor gas stream, thereby producing a second solid carbon dioxide stream and a second carbon dioxide poor gas stream, combining the first solid carbon dioxide stream and the second solid carbon dioxide stream, thereby producing a combined solid carbon dioxide stream, and indirectly exchanging heat between the combined solid carbon dioxide stream and the compressed gas in the first heat exchanger.

  17. Optimization of Heat Exchangers with Dimpled Surfaces to Improve the Performance in Thermoelectric Generators Using a Kriging Model

    Science.gov (United States)

    Li, Shuai; Wang, Yiping; Wang, Tao; Yang, Xue; Deng, Yadong; Su, Chuqi

    2016-11-01

    Thermoelectric generators (TEGs) have become a topic of interest for vehicle exhaust energy recovery. Electrical power generation is deeply influenced by temperature differences, temperature uniformity and topological structures of TEGs. When the dimpled surfaces are adopted in heat exchangers, the heat transfer rates can be augmented with a minimal pressure drop. However, the temperature distribution shows a large gradient along the flow direction which has adverse effects on the power generation. In the current study, the heat exchanger performance was studied in a computational fluid dynamics (CFD) model. The dimple depth, dimple print diameter, and channel height were chosen as design variables. The objective function was defined as a combination of average temperature, temperature uniformity and pressure loss. The optimal Latin hypercube method was used to determine the experiment points as a method of design of the experiment in order to analyze the sensitivity of the design variables. A Kriging surrogate model was built and verified according to the database resulting from the CFD simulation. A multi-island genetic algorithm was used to optimize the structure in the heat exchanger based on the surrogate model. The results showed that the average temperature of the heat exchanger was most sensitive to the dimple depth. The pressure loss and temperature uniformity were most sensitive to the parameter of channel rear height, h 2. With an optimal design of channel structure, the temperature uniformity can be greatly improved compared with the initial exchanger, and the additional pressure loss also increased.

  18. Geometric optimization of cross-flow heat exchanger based on dynamic controllability

    Directory of Open Access Journals (Sweden)

    Alotaibi Sorour

    2008-01-01

    Full Text Available The operation of heat exchangers and other thermal equipments in the face of variable loads is usually controlled by manipulating inlet fluid temperatures or mass flow rates, where the controlled variable is usually one of the output temperatures. The aim of this work is to optimize the geometry of a tube with internal flow of water and an external cross-flow of air, based on its controllability characteristics. Controllability is a useful concept both from theoretical and practical perspective since it tells us if a particular output can be controlled by a particular input. This concept can also provide us with information about the easiest operating condition to control a particular output. A transient model of a tube in cross-flow is developed, where an implicit formulation is used for transient numerical solutions. The aspect ratio of the tube is optimized, subject to volume constraints, based on the optimum operation in terms of controllability. The reported optimized aspect ratio, water mass flow rate and controllability are studied for deferent external properties of the tube.

  19. Optimization research of sextant fan baffle curvature radius in shell and tube heat exchanger

    Science.gov (United States)

    Jin, M.; Liu, H. J.; Wang, X. Y.

    2017-09-01

    For a high shell side pressure drop of the conventional segmental baffles in shell and tube heat exchanger, a novel sextant fan baffle was put forward. To research the influence of baffle curvature radius of the sextant fan baffled shell and tube heat exchanger (SFTHX) on the shell side pressure drop, the heat transfer coefficient and the comprehensive heat transfer performance, six different curvature radius baffles were numerically simulated and experimental studied in this paper. Based on the numerically simulation results, under the same inlet flow conditions, a better comprehensive heat transfer performance can be found in SFTHX with the baffle curvature radius of 1 D, which is higher by 0.84-6.85% more than that of the others. Moreover, the experimental investigation data of SFTHX with baffle curvature radius of 1 D indicates that the numerically simulation can well predict the flow and heat transfer characteristics with the experiment.

  20. Thermal Optimization of the Heat Exchanger in an Automotive Exhaust-Based Thermoelectric Generator

    Science.gov (United States)

    Deng, Y. D.; Liu, X.; Chen, S.; Tong, N. Q.

    2013-07-01

    Recent advances in thermoelectric technologies have made exhaust-based thermoelectric generators (TEGs) promising to recover waste heat. The thermal performance of the heat exchanger in exhaust-based TEGs is studied in this work. In terms of interface temperature and thermal uniformity, the thermal characteristics of heat exchangers with different internal structures, lengths, and materials are discussed. Following computational fluid dynamics simulations, infrared experiments are carried out on a high-performance production engine with a dynamometer. Simulation and experimental results show that a plate-shaped heat exchanger made of brass with fishbone-shaped internal structure and length of 600 mm achieves a relatively ideal thermal performance, which is practically helpful to enhance the thermal performance of the TEG.

  1. Reduction of fine particle emissions from wood combustion with optimized condensing heat exchangers.

    Science.gov (United States)

    Gröhn, Arto; Suonmaa, Valtteri; Auvinen, Ari; Lehtinen, Kari E J; Jokiniemi, Jorma

    2009-08-15

    In this study, we designed and built a condensing heat exchanger capable of simultaneous fine particle emission reduction and waste heat recovery. The deposition mechanisms inside the heat exchanger prototype were maximized using a computer model which was later compared to actual measurements. The main deposition mechanisms were diffusio- and thermophoresis which have previously been examined in similar conditions only separately. The obtained removal efficiency in the experiments was measured in the total number concentration and ranged between 26 and 40% for the given pellet stove and the heat exchanger. Size distributions and number concentrations were measured with a TSI Fast mobility particle sizer (FMPS). The computer model predicts that there exists a specific upper limit for thermo- and diffusiophoretic deposition for each temperature and water vapor concentration in the flue gas.

  2. Optimum distribution of heat exchanger inventory for power density optimization of an endoreversible closed Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lingen Chen; Junlin Zheng; Fengrui Sun [Naval Univ. of Engineering, Faculty 306, Wuhan (China); Chih Wu [U.S. Naval Academy, Mechanical Engineering Dept., Annapolis, MD (United States)

    2001-02-07

    In this paper, the power density (defined as the ratio of the power output to the maximum specific volume in the cycle) is taken as the objective for performance optimisations of an endoreversible closed Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite-time thermodynamics (FTT) or entropy generation minimisation (EGM). The optimum heat conductance distribution corresponding to the optimum power density of the hot- and cold-side heat exchangers for the fixed heat exchanger inventory is analysed using numerical examples. The influence of some design parameters on the optimum heat conductance distribution and the maximum power density and the optimum pressure ratio corresponding to the maximum power density are provided. The power plant design with optimisation leads to higher efficiency and smaller size. (Author)

  3. Assessment and numerical optimization of heat exchangers based on an energy devaluation number; Die Bewertung und numerische Optimierung von Waermeuebertragern anhand einer Energieentwertungszahl

    Energy Technology Data Exchange (ETDEWEB)

    Wenterodt, Tammo

    2013-08-14

    The entropic potential concept as well as the energy devaluation number is developed. Their advantage over common evaluation criteria for heat exchangers is demonstrated. For that purpose, a new method for the automated geometry optimization of heat exchangers based on CFD calculations is presented. It is based on the description of surfaces by Fourier coefficients and their optimization by an evolutionary algorithm.

  4. Laser Processed Heat Exchangers

    Science.gov (United States)

    Hansen, Scott

    2017-01-01

    The Laser Processed Heat Exchanger project will investigate the use of laser processed surfaces to reduce mass and volume in liquid/liquid heat exchangers as well as the replacement of the harmful and problematic coatings of the Condensing Heat Exchangers (CHX). For this project, two scale unit test articles will be designed, manufactured, and tested. These two units are a high efficiency liquid/liquid HX and a high reliability CHX.

  5. A thermoelectric power generating heat exchanger: Part II – Numerical modeling and optimization

    DEFF Research Database (Denmark)

    Sarhadi, Ali; Bjørk, Rasmus; Lindeburg, N.

    2016-01-01

    of the interface surfaces as well as the air gap thermal resistance at the interface. The combined CMY and parallel plate gap model is then further developed to simulate the thermal contact resistance for the case of an interface material. The numerical results show good agreement with the experimental data...... TEG-heat exchanger, the thermal contact resistance between the TEG and the heat exchanger is modeled assuming either an ideal thermal contact or using a combined Cooper–Mikic–Yovanovich (CMY) and parallel plate gap formulation, which takes into account the contact pressure, roughness and hardness...

  6. The optimization of fin-tube heat exchanger with longitudinal vortex generators using response surface approximation and genetic algorithm

    Science.gov (United States)

    Wu, Xuehong; Liu, DanDan; Zhao, Min; Lu, YanLi; Song, Xiaoyong

    2016-09-01

    Delta winglet works better than other vortex generators in improving the performance of fin-tube heat exchangers. In this paper, Response Surface Approximation is used to study the effects of the fin pitch, the ratio of the longitudinal tube pitch to transverse tube pitch, the ratio of both sides V 1 , V h of delta winglets and the attack angle of delta winglets on the performance of fin-tube heat exchanger. Firstly, Twenty-nine numerical group experiments including five times repeated experiments at the central point are conducted. Then, the analyses of variable (ANOVA) and regression are performed to verify the accuracy of the polynomial coefficients. Finally, the optimization of the fin-tube heat exchanger using the Genetic Algorithm is conducted and the best performance of j/f (1/3) is found to be 0.07945, which is consistent with the numerical result.

  7. Stacked Micro Heat Exchange System for Optimized Thermal Coupling of MicroTEGs

    Science.gov (United States)

    Wojtas, N.; Grab, M.; Glatz, W.; Hierold, C.

    2013-07-01

    This study presents modeling and experimental results of micro thermoelectric generators (μTEGs) integrated into a multilayer micro heat exchange system. The multilayer configuration benefits from low heat transfer resistances at small fluid flow rates and at the same time from low required pumping powers. The compact stacked power device allows for high net output power per volume, and therefore a reduction in size, weight, and cost compared with conventional large-scale heat exchangers. The influence of the boundary conditions and the system design parameters on the net output power of the micro heat exchange system was investigated by simulation. The theoretical results showed a major impact of the microchannel dimensions and the μTEG thickness on the overall output performance of the system. By adapting the applied fluid flow rate, the system's net power output can be maximized for varying operating temperatures. Experimental measurements of the cross-flow micro heat exchange system were in good agreement with the performed simulations. A net μTEG output power of 62.9 mW/cm2 was measured for a double-layer system at an applied water inlet temperature difference of 60 K with a Bi2Te3 μTEG ( ZT of 0.12), resulting in a net volumetric efficiency factor of 37.2 W/m3/K2.

  8. Compact, super heat exchanger

    Science.gov (United States)

    Fortini, A.; Kazaroff, J. M.

    1980-01-01

    Heat exchanger uses porous media to enhance heat transfer through walls of cooling channels, thereby lowering wall temperature. Porous media within cooling channel increases internal surface area from which heat can be transferred to coolant. Comparison data shows wall has lower temperature and coolant has higher temperature when porous medium is used within heat exchanger. Media can be sintered powedered metal, metal fibers, woven wire layers, or any porous metal having desired permeability and porosity.

  9. Nature's Heat Exchangers.

    Science.gov (United States)

    Barnes, George

    1991-01-01

    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  10. Active microchannel heat exchanger

    Science.gov (United States)

    Tonkovich, Anna Lee Y [Pasco, WA; Roberts, Gary L [West Richland, WA; Call, Charles J [Pasco, WA; Wegeng, Robert S [Richland, WA; Wang, Yong [Richland, WA

    2001-01-01

    The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.

  11. Single and Multiresponse Adaptive Design of Experiments with Application to Design Optimization of Novel Heat Exchangers

    Science.gov (United States)

    2009-01-01

    annealing ( Serafini , 1992; Nam and Park, 2000) and Timmel’s population based method (Timmel, 1980; Shukla et al., 2005) to name a few. Several variations...Exchangers, British Columbia, Canada. 93. Serafini , P., 1992, “Simulated Annealing for Multiple Objective Optimization Problems,” Proceedings of the

  12. Heat Calculation of Borehole Heat Exchangers

    Directory of Open Access Journals (Sweden)

    S. Filatov

    2013-01-01

    Full Text Available The paper considers a heat calculation method of borehole heat exchangers (BHE which can be used for designing and optimization of their design values and included in a comprehensive mathematical model of heat supply system with a heat pump based on utilization of low-grade heat from the ground.The developed method of calculation is based on the reduction of the problem general solution pertaining to heat transfer in BHE with due account of heat transfer between top-down and bottom-up flows of heat carrier to the solution for a boundary condition of one kind on the borehole wall. Used the a method of electrothermal analogy has been used for a calculation of the thermal resistance and  the required shape factors for calculation of  a borehole filler thermal resistance have been obtained numerically. The paper presents results of heat calculation of various BHE designs in accordance with the proposed method.

  13. Thermoelectric heat exchange element

    Science.gov (United States)

    Callas, James J.; Taher, Mahmoud A.

    2007-08-14

    A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

  14. Thermoelectric heat exchange element

    Energy Technology Data Exchange (ETDEWEB)

    Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

    2007-08-14

    A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

  15. Application of Kriging-based optimization and smoothed particle hydrodynamics in development of a microchannel heat exchanger model

    Energy Technology Data Exchange (ETDEWEB)

    McLellan, J.; Kaya, T.; Goldak, J., E-mail: joshuamclellan@cmail.carleton.ca, E-mail: Tarik.Kaya@carleton.ca, E-mail: jgoldak@mrco2.carleton.ca [Carleton Univ., Ottawa, Ontario (Canada)

    2014-07-01

    A microchannel heat exchanger (MCHX) is a technology that provides increased thermal efficiency in a small volume relative to other types of heat exchangers via an extremely high surface area-to-volume ratio. This characteristic is specifically valued when considering use in small modular reactors. With relatively little design information for commercial MCHXs available in open literature, development of a robust model and optimization thereof for use in nuclear reactors takes on significant importance. Some applications of this technology involve phase change, which is a challenging modelling problem given large volumetric changes of the liquid and gas phases, as well as moving boundaries at the phase interface. This problem is mitigated by use of a Lagrangian formulation such as smoothed particle hydrodynamics (SPH), whose use in the development of the MCHX model is discussed. Additionally, the Kriging optimization algorithm is introduced, including its use to generate a suitable MCHX design. (author)

  16. Design optimization of heat exchangers in topside systems for offshore oil and gas processing

    OpenAIRE

    Bandopadhyay, Mayukh

    2014-01-01

    On a typical oil and gas platform, mechanical equipment units are integral parts of the topside processing system. Heat exchangers, separators, scrubbers, compressors and other equipment units are critical for the proper operation of the processing plant. The hydrocarbon stream received at the first production separator is a mixed stream comprising oil, water and gas phase. This mixed stream is processed in order to separate the oil dominated, water dominated and gas phase. The processing sys...

  17. Design and optimization of a non-TEMA type tubular recuperative heat exchanger used in a regenerative gas turbine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sayyaadi, Hoseyn; Aminian, Hamid Reza [Faculty of Mechanical Engineering-Energy Division, K.N. Toosi University of Technology, P.O. Box: 19395-1999, No. 15-19, Pardis Str., Mollasadra Ave., Vanak Sq., Tehran 1999 143344 (Iran)

    2010-04-15

    A special non-TEMA type tubular recuperative heat exchanger used as a regenerator of a gas turbine cycle is considered for multi-criteria optimization. It is assumed that the recuperator is designed for an existing gas turbine cycle to be retrofitted. Three scenarios for optimization of the proposed system have been considered. In one scenario, the objective is minimizing the cost of recuperator; while in another scenario maximizing the cycle exergetic efficiency is considered. In third scenario, both objectives are optimized simultaneously in a multi-objective optimization approach. Geometric specification of the recuperator including tubes length, tubes outside/inside diameters, tube pitch in the tube bundle, inside shell diameter, outer and inner tube limits of the tube bundle and the total number of disc and doughnut baffles are considered as decision variables. Combination of these objectives and decision variables with suitable engineering and physical constraints (including NO{sub x} and CO emission limitations) makes a set of MINLP optimization problem. Optimization programming in MATLAB is performed using one of the most powerful and robust multi-objective optimization algorithms namely NSGA-II. This approach which is based on the Genetic Algorithm is applied to find a set of Pareto optimal solutions. Pareto optimal frontier is obtained and a final optimal solution is selected in a decision-making process. It is shown that the multi-objective optimization scenario can be considered as a generalized optimization approach in which balances between economical viewpoints of both heat exchanger manufacturer and end user of recuperator. (author)

  18. Optimization of the Dynamic Behavior of a Heat Exchanger Subject to Fouling Comparison of Three Optimization Models

    Directory of Open Access Journals (Sweden)

    Michel Feidt

    1999-06-01

    Full Text Available

    This paper proposes a dynamic analysis of fouling of a heat exchanger. The used criteria is mean thermal power exchanged over time. The proposed results are relative to cocurrent configuration and tubular geometry of the heat exchanger, but other cases have been explored (countercurrent, plane geometry. An optimum time is determined, sensitivity analysis of the corresponding value to three cases of flow regimes (constant mass flow rate, constant flow velocity and constant pumping power and various kinetics of fouling has been performed. The time of stop of the installation for cleaning is the main parameter. All the results are proposed in nondimensional form.

    •  This paper was presented at the ECOS’98 Conference in Nancy, June 8-10, 1998

  19. Heat exchanger design handbook

    CERN Document Server

    Thulukkanam, Kuppan

    2013-01-01

    Completely revised and updated to reflect current advances in heat exchanger technology, Heat Exchanger Design Handbook, Second Edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topics--all while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians, designers, and manufacturers involved in heat exchange between two or more fluids.See What's New in the Second Edition: Updated information on pressure vessel codes, manufacturer's association standards A new c

  20. Optimization of Fin Distribution to Improve the Temperature Uniformity of a Heat Exchanger in a Thermoelectric Generator

    Science.gov (United States)

    Wang, Yiping; Wu, Cheng; Tang, Zebo; Yang, Xue; Deng, Yadong; Su, Chuqi

    2015-06-01

    Thermoelectric generators (TEGs) are currently a topic of interest for energy recovery in vehicles. By applying TEGs to the outside surface of the exhaust tailpipe, a small amount of electrical power can be generated because of the temperature difference between the hot exhaust gases and the automobile coolant. The amount of power is anticipated to be a few hundred watts based on the expected temperature difference and the properties of the thermoelectric materials used in TEGs. It is well know that, for thermoelectric exhaust energy recovery, the temperature uniformity of the heat exchangers has a strong influence on the electric power generation. In the current research, the temperature uniformity of a heat exchanger was improved by optimizing the fin distribution to maximize the electric power generated for a given vehicle TEG. A computational fluid dynamics (CFD) model of the heat exchanger was constructed to assess the influence of different fin distributions on the temperature uniformity and the pressure drop in the exhaust system. For the fin distributions, four factors were considered: the length of, spacing between, angle of, and thickness of the fins. Based on these four factors, a design of experiments study using the orthogonal experimental method was conducted to analyze the sensitivity to the design variables and build a database to set up a surrogate model using the Kriging response surface method. A multi-island genetic algorithm was used to optimize the fin distribution based on this surrogate model. To validate the accuracy of the CFD model, a generic heat exchanger module was manufactured and a related testbed constructed, then the temperature distribution on the surface of the exchanger was measured to compare with the results obtained by CFD.

  1. Microplate Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple cooling...

  2. Counterflow Regolith Heat Exchanger

    Science.gov (United States)

    Zubrin, Robert; Jonscher, Peter

    2013-01-01

    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  3. New models for conventional and heat exchangers enhanced with tube inserts for heat exchanger network retrofit

    OpenAIRE

    Jiang, N; Shelley, J D; Smith, Robin

    2014-01-01

    The retrofit of heat exchanger networks requires detailed models of the heat exchangers for the detailed assessment of network performance. Network retrofit options include heat transfer enhancement. There is thus a requirement for detailed models of heat exchanger performance, including heat transfer enhancement, suitable for inclusion in network retrofit optimization algorithms. Such models must be robust, computationally efficient and accurate enough to reflect the heat transfer and pressu...

  4. Heat exchanger restart evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

    1992-02-28

    On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4kA was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized herein.

  5. Scraped surface heat exchangers.

    Science.gov (United States)

    Rao, Chetan S; Hartel, Richard W

    2006-01-01

    Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.

  6. Microgravity condensing heat exchanger

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

    2011-01-01

    A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

  7. Heat exchange apparatus

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2003-08-12

    A heat exchange apparatus comprising a coolant conduit or heat sink having attached to its surface a first radial array of spaced-apart parallel plate fins or needles and a second radial array of spaced-apart parallel plate fins or needles thermally coupled to a body to be cooled and meshed with, but not contacting the first radial array of spaced-apart parallel plate fins or needles.

  8. Small particle heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A.J.

    1978-06-01

    A dispersion of small absorbing particles forms an ideal system to collect radiant energy, transform it to heat, and efficiently transfer the heat to a surrounding fluid. If the heated fluid is a pressurized gas, it can be passed through an expansion turbine to create useful mechanical energy. The most obvious application of this technique is its use in a solar collection system. In this case, the incoming sunlight is used to heat a compressed gas in an engine utilizing a Brayton cycle. The solar collection system may utilize high concentration as provided by a central receiver or parabolic dish, medium concentration from a linear collector, or possibly no concentration using a flat plate collector, if precautions were taken to reduce the heat losses. The same concept may be applied generally to non-solar heat exchangers. These may be of the type used to heat a gas from a combustion source, or in general as a gas to gas heat exchanger. The latter application may be limited to rather high temperature. Each of the above applications is discussed. First, a description of the concept is applied to a solar central-tower system. The general principles are described, including the optical and physical characteristics of the particles, the confinement of the gas-particle mixture, and the system considerations; the latter include the amount and type of particles, the receiver efficiency and the generation of the particles. The same considerations are reviewed for applications to linear trough and flat plate receivers. Finally, the use of small particles in non-solar heat exchangers is considered.

  9. Microtube strip heat exchanger

    Science.gov (United States)

    Doty, F. D.

    1991-04-01

    During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchangers. The team has begun a heat exchanger stress analysis; however, they have been concentrating the bulk of their analytical energies on a computational fluid dynmaics (CFD) model to determine the location and magnitude of shell-side flow maldistribution which decreases heat exchanger effectiveness. DSI received 120 fineblanked tubestrips from Southern Fineblanking (SFB) for manufacturing process development. Both SFB and NIST provided inspection reports of the tubestrips. DSI completed the tooling required to encapsulate a tube array and press tubestrips on the array. Pressing the tubestrips on tube arrays showed design deficiencies both in the tubestrip design and the tooling design. DSI has a number of revisions in process to correct these deficiencies. The research effort has identified a more economical fusible alloy for encapsulating the tube array, and determined the parameters required to successfully encapsulate the tube array with the new alloy. A more compact MTS heat exchanger bank was designed.

  10. NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2008-09-01

    heat exchanger with Na as the heat exchanger coolant. In order to design a very efficient and effective heat exchanger one must optimize the design such that we have a high heat transfer and a lower pressure drop, but there is always a trade-off between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change will be presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost.

  11. METHODOLOGY FOR DETERMINING THE OPTIMAL CLEANING PERIOD OF HEAT EXCHANGERS BY USING THE CRITERIA OF MINIMUM COST

    Directory of Open Access Journals (Sweden)

    Yanileisy Rodríguez Calderón

    2015-04-01

    Full Text Available One of the most serious problems of the Process Industry is that when planning the maintenance of the heat exchangers is not applied the methodologies based on economic criteria to optimize periods of cleaning surfaces resulting in additional costs for the company and for the country. This work develops and proposes a methodical based on the criterion of Minimum Cost for determining the optimal cleaning period. It is given an example of application of this method to the case of intercoolers of a centrifugal compressor with a high fouling level.It occurs this because is used sea water with many microorganisms as cooling agent which severely embeds transfer surfaces of side water. The methodology employed can be generalized to other applications.

  12. Simulation and experimental study on thermal optimization of the heat exchanger for automotive exhaust-based thermoelectric generators

    Directory of Open Access Journals (Sweden)

    C.Q. Su

    2014-11-01

    Full Text Available Thermoelectric technology has revealed the potential for automotive exhaust-based thermoelectric generator (TEG, which contributes to the improvement of the fuel economy of the engine-powered vehicle. As a major factor, thermal capacity and heat transfer of the heat exchanger affect the performance of TEG effectively. With the thermal energy of exhaust gas harvested by thermoelectric modules, a temperature gradient appears on the heat exchanger surface, so as the interior flow distribution of the heat exchanger. In order to achieve uniform temperature distribution and higher interface temperature, the thermal characteristics of heat exchangers with various heat transfer enhancement features are studied, such as internal structure, material and surface area. Combining the computational fluid dynamics simulations and infrared test on a high-performance engine with a dynamometer, the thermal performance of the heat exchanger is evaluated. Simulation and experiment results show that a plate-shaped heat exchanger made of brass with accordion-shaped internal structure achieves a relatively ideal performance, which can practically improve overall thermal performance of the TEG.

  13. An Environmental and Economic Assessment for Selecting the Optimal Ground Heat Exchanger by Considering the Entering Water Temperature

    Directory of Open Access Journals (Sweden)

    Jimin Kim

    2015-07-01

    Full Text Available In order to solve environmental problems such as global warming and resource depletion in the construction industry, interest in new renewable energy (NRE systems has increased. The ground source heat pump (GSHP system is the most efficient system among NRE systems. However, since the initial investment cost of the GSHP is quite expensive, a feasibility study needs to be conducted from the life-cycle perspective. Meanwhile, the efficiency of GSHP depends most significantly on the entering water temperature (EWT of the ground heat exchanger (GHE. Therefore, this study aims to assess the environmental and economic effects of the use of GHE for selecting the optimal GHE. This study was conducted in three steps: (i establishing the basic information and selecting key factors affecting GHE performances; (ii making possible alternatives of the GHE installation by considering EWT; and (iii using life-cycle assessment and life-cycle cost, as well as comprehensive evaluation of the environmental and economic effects on the GHE. These techniques allow for easy and accurate determination of the optimal design of the GHE from the environmental and economic effects in the early design phase. In future research, a multi-objective decision support model for the GSHP will be developed.

  14. Liquid/liquid heat exchanger

    Science.gov (United States)

    Miller, C. G.

    1980-01-01

    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  15. Fault-Tolerant Heat Exchanger

    Science.gov (United States)

    Izenson, Michael G.; Crowley, Christopher J.

    2005-01-01

    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  16. Counterflow Regolith Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat...

  17. "Bottle-Brush" Heat Exchanger

    Science.gov (United States)

    Tward, E.; Gatewood, J. R.

    1982-01-01

    Heat exchanger consists of a metal tube with wires extending inward from wall. Conduction of heat along wires improves heat transfer to gas or other filling. Fluid is heated throughout the cross section of tube. Suggested applications are refrigerators, heat engines, thermal instrumentation, and heat switches.

  18. Cryogenic regenerative heat exchangers

    CERN Document Server

    Ackermann, Robert A

    1997-01-01

    An in-depth survey of regenerative heat exchangers, this book chronicles the development and recent commercialization of regenerative devices for cryogenic applications. Chapters cover historical background, concepts, practical applications, design data, and numerical solutions, providing the latest information for engineers to develop advanced cryogenic machines. The discussions include insights into the operation of a regenerator; descriptions of the cyclic and fluid temperature distributions in a regenerator; data for various matrix geometries and materials, including coarse and fine bronze, stainless steel-woven wire mesh screens, and lead spheres; and unique operating features of cryocoolers that produce deviations from ideal regenerator theory.

  19. Hybrid Heat Exchangers

    Science.gov (United States)

    Tu, Jianping Gene; Shih, Wei

    2010-01-01

    A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

  20. Synthesis of Heat Exchanger Network Considering Multipass Exchangers

    Institute of Scientific and Technical Information of China (English)

    李绍军; 姚平经

    2001-01-01

    Many methods have been proposed for synthesis of heat exchanger networks in recent years, most of which consider single pass exchangers. In this study some evolutionary rules have been proposed for synthesis of multipass exchanger networks. The method is based on the heuristic that optimal networks should feature maximum energy recovery and have the minimum number of shells. The effectiveness of the developed evolutionary rules is demonstrated through some literature examples.

  1. Heat exchangers for waste heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rabghi, O.M.; Akyurt, M.; Najjar, Y.S.H.; Alp, T. (King Abdulaziz Univ., Jeddah (Saudi Arabia). College of Engineering)

    1993-01-01

    A survey is made of the equipment used for heat recovery and utilization. Types and merits of commonly employed heat exchangers are presented, and criteria for selecting heat exchangers are summarized. Applications for waste heat recovery are emphasized. It is concluded that careful selection and operation of such equipment would be expected to result in energy savings as well as problem-free operation. (author)

  2. Optimizing Design for Shell and Tube Heat Exchanger Based on MATLAB%基于MATLAB的管壳式换热器优化设计

    Institute of Scientific and Technical Information of China (English)

    王雷; 蒋宁

    2012-01-01

    基于MATLAB 7.6开发了管壳式换热器,充分利用压降优化设计软件.通过改变换热器结构,充分利用管壳程压降,提高传热系数,减少换热面积.通过案例分析表明,充分利用压降后,换热器的传热系数提高了21%,换热面积减小了20%,大大减少了换热器的投资费用.%Making best use of pressure drop, the paper developed an optimizing design software for shell and tube heat exchanger based on MATLAB 7. 6. By varying the structures of heat exchanger, fully using of pressure drop between shell and tube gap can improve heat transfer coefficient and reduce heat exchange area. By analysis of the designed case, the results prove that the heat transfer coefficient increases by 21% and the heat exchange area reduces by 20% , thus the cost of heat-exchanger can be decreased greatly. [Ch,4 fig. 2 tab. 10 ref.

  3. Numerical Analysis on Longitudinal Location Optimization of Vortex Generator in Compact Heat Exchangers

    DEFF Research Database (Denmark)

    Gorji, M.; Mirgolbababei, H.; Barari, Amin

    2011-01-01

    In this paper, numerical, curvilinear and turbulent model has been used to investigate the effect of vortex generator's longitudinal displacement on heat transfer and fluid flow in different Reynolds numbers ranging from 500 to 3000. The numerical model has been validated with experimental result...

  4. Next Generation Microchannel Heat Exchangers

    CERN Document Server

    Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

    2013-01-01

    In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

  5. Numerical Analysis on Optimization of a Fin and Tube Type Adsorber/Desorber Heat Exchanger using ACF/C2H5OH Pair

    Science.gov (United States)

    Kariya, Keishi; Kuwahara, Ken; Koyama, Shigeru

    This study deals with a two dimensional numerical analysis of the fin and tube type adsorber/desorber heat exchanger design such as fin height, fin pitch, fin thickness and tube diameter effect on the performance of closed adsorption cooling system with activated carbon fiber (ACF) of type A-20, which has relatively higher surface area, and ethanol pair. The simulation results show that the fin tube diameter is effective on the performance of the heat exchanger. It is also found that the cycle COP can be optimized in the condition of fin pitch 4.5mm and fin height 20mm, respectively when other parameters are fixed.

  6. Interfacing heat exchanger network synthesis and detailed heat exchanger design

    Energy Technology Data Exchange (ETDEWEB)

    Polley, G.T.; Panjeh Shahi, M.H. (Manchester Univ. (United Kingdom). Inst. of Science and Technology)

    1991-11-01

    Current heat exchanger network synthesis targeting and design procedures involve the use of assumed stream heat transfer coefficients. However, during detailed heat exchanger design, allowable pressure drops are often the most critical factors. The result can be big differences between the exchanger sizes and costs anticipated by the network designer and those realised by the exchanger designer. This in turn prejudices any optimisation attempted at the network design stage. In this paper it is shown how allowable pressure drop can be used as a basis of network design and consistency between expectation and realisation achieved. (author).

  7. Heat exchanger leakage problem location

    Directory of Open Access Journals (Sweden)

    Jícha Miroslav

    2012-04-01

    Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  8. Heat exchanger leakage problem location

    Science.gov (United States)

    Hejčík, Jiří; Jícha, Miroslav

    2012-04-01

    Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  9. Analysis and optimization of the heat transfer coefficient of a finned heat exchanger submitted to natural convection; Analise e otimizacao do coeficiente de transferencia de calor de um trocador aletado submetido a conveccao natural

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Alan Carlos Bueno da

    1997-07-01

    A heat transfer (condenser) of a domestic freezer was tested in a vertical channel in order to study the influence of the chimney effect in the optimization of the heat transfer coefficient. The variation of the opening of the channel, position and the heating power of the heat exchanger in the heat transfer coefficient was considered. The influence of the surface emissivity on the heat transfer by thermal radiation was studied with the heat exchanger testes without paint and with black paint. The air velocity entering the channel was measured with a hot wire anemometer. In order to evaluate the chimney effect, the heat exchanger was testes in a open ambient. This situation simulates its operational conditions when installed on the freezer system. The variables collected in the experimental procedures was gathered in the form of dimensionless parameters as Nusselt, Rayleigh, Grashof and Prandtl numbers, and dimensional parameters of the convection. The results showed that the highest heat transfer value occurred when both a specific position and a specific channel opening were used. The experiments pointed out that the radiation contribution must be considered in heat transfer calculations. The conclusions showed that different channel openings can improve the heat transfer coefficient in this heat transfer exchanger. (author)

  10. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  11. Selection of Rational Heat Transfer Intensifiers in the Heat Exchanger

    Directory of Open Access Journals (Sweden)

    S. A. Burtsev

    2016-01-01

    Full Text Available The paper considers the applicability of different types of heat transfer intensifiers in the heat exchange equipment. A review of the experimental and numerical works devoted to the intensification of the dimpled surface, surfaces with pins and internally ribbed surface were presented and data on the thermal-hydraulic characteristics of these surfaces were given. We obtained variation of thermal-hydraulic efficiency criteria for 4 different objective functions and 15 options for the intensification of heat transfer. This makes it possible to evaluate the advantages of the various heat transfer intensifiers. These equations show influence of thermal and hydraulic characteristics of the heat transfer intensifiers (the values of the relative heat transfer and drag coefficients on the basic parameters of the shell-and-tube heat exchanger: the number and length of the tubes, the volume of the heat exchanger matrix, the coolant velocity in the heat exchanger matrix, coolant flow rate, power to pump coolant (or pressure drop, the amount of heat transferred, as well as the average logarithmic temperature difference. The paper gives an example to compare two promising heat transfer intensifiers in the tubes and shows that choosing the required efficiency criterion to search for optimal heat exchanger geometry is of importance. Analysis is performed to show that a dimpled surface will improve the effectiveness of the heat exchanger despite the relatively small value of the heat transfer intensification, while a significant increase in drag of other heat transfer enhancers negatively affects their thermalhydraulic efficiency. For example, when comparing the target functions of reducing the heat exchanger volume, the data suggest that application of dimpled surfaces in various fields of technology is possible. But there are also certain surfaces that can reduce the parameters of a heat exchanger. It is shown that further work development should be aimed at

  12. Milk fouling in heat exchangers.

    NARCIS (Netherlands)

    Jeurnink, Th.J.M.

    1996-01-01

    The mechanisms of fouling of heat exchangers by milk were studied. Two major fouling mechanisms were indentified during the heat treatment of milk: (i) the formation and the subsequent deposition of activated serum protein molecules as a result of the heat denaturation; (ii) the precipitation of cal

  13. Mathematical Modeling of Spiral Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Probal Guha , Vaishnavi Unde

    2014-04-01

    Full Text Available Compact Heat Exchangers (CHEs are increasingly being used on small and medium scale industries. Due to their compact size and efficient design, they facilitate more efficient heat transfer. Better heat transfer would imply lesser fuel consumption for the operations of the plant, giving improvement to overall efficiency. This reduction in consumption of fuel is a step towards sustainable development. This report exclusively deals with the study the spiral heat exchanger.The design considerations for spiral heat exchanger is that the flow within the spiral has been assumed as flow through a duct and by using Shah London empirical equation for Nusselt number design parameters are further optimized.This is accompanied by a detailed energy balance to generate a concise mathematical model

  14. Heat exchanger using graphite foam

    Science.gov (United States)

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  15. Optimization of Heat Gain by Air Exchange through the Window of Cold Storage Using S/N Ratio and ANOVA Analysis”

    Directory of Open Access Journals (Sweden)

    Dr. Nimai Mukhopadhyay

    2017-04-01

    Full Text Available Energy is at scarcity, crisis of energy is leading towards a world where growth might come to an absolute hold and optimizing the processes might give a way out to save energy for future generations and give some positive way out. In this situation if the maximum heat energy (Q is absorbed by the evaporator inside the cold room through convective heat transfer process in terms of –heat transfer due to convection and heat transfer due to condensation and also heat enter in the cold store due to air exchange through the windows more energy has to be wasted to maintain the evaporator space at the desired temperature range of 2-6 degree centigrade. In this paper we have tried to optimize the heat gain by the air exchange through the windows of cold storage in the evaporator space using regression analysis. Temperature difference (dT, Height of cold store Window (H and Relative Humidity (RH are the basic variable and three ranges are taken each of them in the model development. Graphical interpretations from the model justify the reality through S/N ratio calculation and ANOVA analysis

  16. Heat exchanger design based on economic optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Caputo, Antonio C.; Pelagagge, Pacifico M.; Salini, Paolo [University of L' Aquila, Engineering Faculty, Monteluco di Roio 67100, L' Aquila (Italy)

    2008-07-15

    Owing to the wide utilization of heat exchangers in industrial processes, their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which gradually change design parameters until a satisfying solution, which meets the design specifications, is reached. However, such methods, besides being time consuming, do not guarantee the reach of an economically optimal solution. In this paper a procedure for optimal design of shell and tube heat exchangers is proposed, which utilizes a genetic algorithm to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping. In order to verify the capability of the proposed method, three case studies are also presented showing that significant cost reductions are feasible with respect to traditionally designed exchangers. In particular, in the examined cases a reduction of total costs up to more than 50% was observed. (author)

  17. Modeling and optimization of a heat-pump-assisted high temperature proton exchange membrane fuel cell micro-combined-heat-and-power system for residential applications

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Kær, Søren Knudsen; Nielsen, Mads Pagh

    2015-01-01

    In this study a micro-combined-heat-and-power (micro-CHP) system is coupled to a vapor-compression heat pump to fulfill the residential needs for heating (space heating and water heating) and electricity in detached single-family households in Denmark. Such a combination is assumed to be attractive...... for application, since both fuel cell technology and electric heat pumps are found to be two of the most efficient technologies for generation/conversion of useful energy. The micro-CHP system is fueled with natural gas and includes a fuel cell stack, a fuel processor and other auxiliary components. The micro....... The variational loads are considered from full to quarter load, and the micro-CHP system is optimized in terms of operating thermophysical parameters for every different load. The results clearly indicate the capability of the proposed system to perform efficiently throughout all necessary load changes to fulfill...

  18. Development and benefits of air/air-heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, H.W.; Cremer, P.

    1986-02-01

    After the first experiments using glass tube heat exchangers, many air/air heat exchangers have made within ten years the breakthrough as ''interior climate improvers'' in stables. Especially inexpensive synthetic panels, foils and self-construction, ribbed heat exchangers are very popular among farmers. Based on thorough installation planning and satisfactory operating results, thousands of heat exchangers were installed, through which heating oil and fuel gas are being replaced as energy sources, and through an improved interior climate, the productivity can be optimized in fattening and rearing houses. (orig.).

  19. Bistability in radiative heat exchange

    Science.gov (United States)

    Rudakov, V. I.; Ovcharov, V. V.; Prigara, V. P.

    2008-08-01

    The possibility of a bistable regime in systems with radiative heat exchange is theoretically demonstrated for the first time. The transfer characteristics of a radiation-closed stationary system have been calculated, in which the radiator is a blackbody and the absorber is made of a material with the absorptivity sharply increasing in a certain temperature interval. The radiator and absorber are separated by a vacuum gap. The heat exchange between the system and the environment is controlled by varying the flow rate of a heat-transfer agent cooling the absorber. The output parameter of a bistable system is the absorber temperature, while the input parameter can be either the radiator temperature or the heat-transfer agent flow rate. Depending on the choice of the input parameter, the transfer characteristic of the system is either represented by a usual S-like curve or has an inverted shape.

  20. [Biofouling of heat exchange tubes].

    Science.gov (United States)

    Montero, F; Pintado, J L

    1994-01-01

    We compared the biofouling behavior of different materials (admiralty brass, stainless steel, and titanium) commonly used to construct heat exchangers in thermoelectric plants. The incidence of film formation on the loss of heat during transference was assessed, and analyzed in terms of plant efficiency and corrosion, both general and localized development. Our results showed that the resistance of titanium and stainless steel to corrosion was similar, and much better than that of admiralty brass. Biofouling, however, was higher in the first two materials.

  1. Exergo-ecological evaluation of heat exchanger

    Directory of Open Access Journals (Sweden)

    Stanek Wojciech

    2014-01-01

    Full Text Available Thermodynamic optimization of thermal devices requires information about the influence of operational and structural parameters on its behaviour. The interconnections among parameters can be estimated by tools such as CFD, experimental statistic of the deviceetc. Despite precise and comprehensive results obtained by CFD, the time of computations is relatively long. This disadvantage often cannot be accepted in case of optimization as well as online control of thermal devices. As opposed to CFD the neural network or regression is characterized by short computational time, but does not take into account any physical phenomena occurring in the considered process. The CFD model of heat exchanger was built using commercial package Fluent/Ansys. The empirical model of heat exchanger has been assessed by regression and neural networks based on the set of pseudo-measurements generated by the exact CFD model. In the paper, the usage of the developed empirical model of heat exchanger for the minimisation of TEC is presented. The optimisationconcerns operational parameters of heat exchanger. The TEC expresses the cumulative exergy consumption of non-renewable resources. The minimization of the TEC is based on the objective function formulated by Szargut. However, the authors extended the classical TEC by the introduction of the exergy bonus theory proposed by Valero. The TEC objective function fulfils the rules of life cycle analysis because it contains the investment expenditures (measured by the cumulative exergy consumption of non-renewable natural resources, the operation of devices and the final effects of decommissioning the installation.

  2. High temperature heat exchanger studies for applications to gas turbines

    Science.gov (United States)

    Min, June Kee; Jeong, Ji Hwan; Ha, Man Yeong; Kim, Kui Soon

    2009-12-01

    Growing demand for environmentally friendly aero gas-turbine engines with lower emissions and improved specific fuel consumption can be met by incorporating heat exchangers into gas turbines. Relevant researches in such areas as the design of a heat exchanger matrix, materials selection, manufacturing technology, and optimization by a variety of researchers have been reviewed in this paper. Based on results reported in previous studies, potential heat exchanger designs for an aero gas turbine recuperator, intercooler, and cooling-air cooler are suggested.

  3. Compact Ceramic Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, Charles [Ceramatec, Inc., Salt Lake City, UT (United States)

    2016-10-31

    The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.

  4. Modelling of Split Condenser Heat Pump with Limited Set of Plate Heat Exchanger Dimensions

    DEFF Research Database (Denmark)

    Christensen, Stefan Wuust; Elmegaard, Brian; Markussen, Wiebke Brix

    2017-01-01

    This paper presents a numerical study of optimal plate dimensions in a split condenser heat pump (SCHP), using ammonia as refrigerant. The SCHP setup differs from a traditional heat pump (THP) setup in the way that two separate water streams on the secondary side of the condenser are heated...... in parallel to different temperature levels, whereas only one stream is heated in a THP. The length/width ratio of the plate heat exchangers on the high pressure side of a SCHP was investigated to find the optimal plate dimensions with respect to minimum area of the heat exchangers. The total heat exchanger...... area was found to decrease with an increasing length/width ratio of the plates. The marginal change in heat exchanger area was shown to be less significant for heat exchangers with high length/width ratios. In practice only a limited number of plate dimensions are available and feasible...

  5. Experimental study on heat exchange of several types of exchangers

    Institute of Scientific and Technical Information of China (English)

    周志华; 赵振华; 于洋

    2009-01-01

    Aiming at the ground-coupled source heat pump that possesses the shortcomings of occupying larger land,this article studies the heat exchanged of heat exchanger in piling,and compares it with common heat exchangers buried directly. The result indicates that the heat exchanger makes the best use of structure of building,saves land,reduces the construction cost,and the heat exchanged is obviously more than exchangers buried directly. In winter condition,when W-shape pipe heat exchanger in pile foundation is 50 m deep and diameter is 800 mm,it transfers 1.2-1.3 times as large as the one of single U-shape buried directly at the flow rate of 0.6 m/s,whose borehole diameter is 300 mm. And in summer condition it does about 2.0-2.3 times as that of U-shape one.

  6. Application of explosive welding to heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, G.

    1983-10-01

    The subject is discussed under the headings: advantages of explosive welding; principle of explosive welding; explosive welding of tubes; metallurgy of explosive welds (micrographs; microhardness); tubular heat exchangers; plugging; sleeving; retubing; construction of new heat exchangers; thermal sleeves.

  7. Pressurized bellows flat contact heat exchanger interface

    Science.gov (United States)

    Voss, Fred E. (Inventor); Howell, Harold R. (Inventor); Winkler, Roger V. (Inventor)

    1990-01-01

    Disclosed is an interdigitated plate-type heat exchanger interface. The interface includes a modular interconnect to thermally connect a pair or pairs of plate-type heat exchangers to a second single or multiple plate-type heat exchanger. The modular interconnect comprises a series of parallel, plate-type heat exchangers arranged in pairs to form a slot therebetween. The plate-type heat exchangers of the second heat exchanger insert into the slots of the modular interconnect. Bellows are provided between the pairs of fins of the modular interconnect so that when the bellows are pressurized, they drive the plate-type heat exchangers of the modular interconnect toward one another, thus closing upon the second heat exchanger plates. Each end of the bellows has a part thereof a thin, membrane diaphragm which readily conforms to the contours of the heat exchanger plates of the modular interconnect when the bellows is pressurized. This ensures an even distribution of pressure on the heat exchangers of the modular interconnect thus creating substantially planar contact between the two heat exchangers. The effect of the interface of the present invention is to provide a dry connection between two heat exchangers whereby the rate of heat transfer can be varied by varying the pressure within the bellows.

  8. Improved Ceramic for Heat Exchangers

    Science.gov (United States)

    Herbell, T. P.; Rauch, H. W.; Mccreeght, L. R.

    1982-01-01

    Most promising composition developed in investigation consisted of mixed oxides described generically as ZrMAS. Has been commercially designated as GE-7808. Material was obtained from low-cost clay/talc mixture. Overall assessment of ZrMAS indicates it is a viable candidate for heat-exchanger application in automotive gas-turbine engines and possibly other areas that require dielectric materials of moderate refractoriness, good corrosion resistance, and excellent thermal-shock resistance.

  9. Acoustic streaming with heat exchange

    Science.gov (United States)

    Gubaidullin, A. A.; Pyatkova, A. V.

    2016-10-01

    Acoustic streaming in a cylindrical cavity with heat exchange is numerically investigated. The cavity is filled with air. The boundaries of the cavity are maintained at constant temperature. The features of acoustic streaming manifesting with the decrease in the frequency of vibration in comparison with the resonant frequency are determined. The influence of the nonlinearity of process on acoustic streaming is shown. The nonlinearity is caused by the increase of the vibration amplitude.

  10. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  11. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  12. evaluation of total annual costs of heat exchanger networks using ...

    African Journals Online (AJOL)

    This study presents pinch analysis of some heat exchanger networks (HENs) problems using Hint integration (HINT) software. ... and the general optimization of the networks for minimum TAC for the three problems solved. ... Article Metrics.

  13. Automatic evolution of heat exchanger networks with simultaneous heat exchanger design

    Energy Technology Data Exchange (ETDEWEB)

    Liporace, F.S.; Pessoa, F.L.P.; Queiroz, E.M. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Engenharia Quimica]. E-mail: lipo@h2o.eq.ufrj.br; lipo@hexanet.com.br

    1999-03-01

    Recently, a new software (AtHENS) that automatically synthesizes a heat exchanger network with minima consumption of utilities was developed. This work deals with the next step, which represents the evolution of the initial network. Hence, new procedures to identify and break loops are incorporated, for which a new algorithm is proposed. Also, a heat exchanger design procedure which uses the available pressure drop to determine the film coefficient on the tube side and shell side is added, providing the utilization of more realistic heat exchangers in the network during its optimization. Results obtained from a case study point to the possibility of equipment design having a strong influence on the network synthesis. (author)

  14. AUTOMATIC EVOLUTION OF HEAT EXCHANGER NETWORKS WITH SIMULTANEOUS HEAT EXCHANGER DESIGN

    Directory of Open Access Journals (Sweden)

    F.S. LIPORACE

    1999-03-01

    Full Text Available Recently, a new software (AtHENS that automatically synthesizes a heat exchanger network with minima consumption of utilities was developed. This work deals with the next step, which represents the evolution of the initial network. Hence, new procedures to identify and break loops are incorporated, for which a new algorithm is proposed. Also, a heat exchanger design procedure which uses the available pressure drop to determine the film coefficient on the tube side and shell side is added, providing the utilization of more realistic heat exchangers in the network during its optimization. Results obtained from a case study point to the possibility of equipment design having a strong influence on the network synthesis.

  15. SAFE gas turbine cycle primary heat exchangers

    Science.gov (United States)

    Reid, Robert S.; Kapernick, Richard J.

    2002-01-01

    Los Alamos National Laboratory and Marshall Space Flight Center are jointly developing two modular heat pipe heat exchangers, collectively named FIGMENT (Fission Inert Gas Metal Exchanger for Non-nuclear Testing). The FIGMENT heat exchangers are designed to transfer power from the SAFE nuclear reactor cores to gas turbine energy converters. A stainless steel prototype heat exchanger will be built during 2002 in preparation for the construction of a larger refractory metal version. Two promising FIGMENT stainless steel heat exchanger concepts are reviewed here. .

  16. Finned Small Diameter Tube Heat Exchanger

    Science.gov (United States)

    Dang, Chaobin; Daiguji, Hirofumi; Hihara, Eiji; Tokunaga, Masahide

    The performance of fined small tube heat exchangers was investigated both experimentally and theoretically. The Inner diameters of tubes were 1.0mm, 2.1mm and 4.0mm. Exchanged heat and pressure drop obtained from numerical simulation agreed well with the experimental ones. Calculation results show that the volume of a 2.0mm tube heat exchanger can be reduced to 33% of that of a 4mm tube heat exchanger with the same capacity. In addition the distribution of two-phase flow in a branching unit was investigated by measuring downstream temperature distribution. The flow distribution in a branching unit strongly affects the exchanged heat.

  17. GMDH-type neural network modeling and genetic algorithm-based multi-objective optimization of thermal and friction characteristics in heat exchanger tubes with wire-rod bundles

    Science.gov (United States)

    Rahimi, Masoud; Beigzadeh, Reza; Parvizi, Mehdi; Eiamsa-ard, Smith

    2016-08-01

    The group method of data handling (GMDH) technique was used to predict heat transfer and friction characteristics in heat exchanger tubes equipped with wire-rod bundles. Nusselt number and friction factor were determined as functions of wire-rod bundle geometric parameters and Reynolds number. The performance of the developed GMDH-type neural networks was found to be superior in comparison with the proposed empirical correlations. For optimization, the genetic algorithm-based multi-objective optimization was applied.

  18. Comparison of a Conventional Heat Exchangers with a New Designed Heat Exchanger Experimentally

    Directory of Open Access Journals (Sweden)

    Tansel Koyun

    2014-04-01

    Full Text Available In this study, the air-water heat exchanger designed have been experimentally compared to conventional heat exchangers with and without fin. The same parameters for the three heat exchangers (pump flow, heating power, etc... have been used. In the experiments, speed-flow adjustment has been made to supply heat transfer at an optimum. As a result, during the circulation of water in pipe of the air-water heat exchanger, the corrosion fouling factor has not been formed. In addition, the efficiency of the new designed heat exchanger has been found between fin and finless heat exchanger efficiencies. The results have been shown in the diagrams.

  19. A core alternative[Heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, R.H. [Chart Heat Exchangers, Wisconsin (United States)

    2001-09-01

    The development of the efficient Core-in-kettle heat exchangers by Chart Heat Exchangers as an alternative to shell and tube exchangers is reported, and its use as condensers and reboilers in ethylene plants and refrigerant condensers and chillers in natural gas processing and liquid natural gas (LNG) plants are discussed. The novel technology is described with details given of the replacement of the tube bundle with a Chart brazed aluminium plate-fin heat exchanger core, the operation of the exchanger, the savings achieved by installing these heat exchangers in new or existing plants, and Core-in-Kettle retrofits of existing shell and tube heat exchangers. The limitations of the use of Core-in-Kettle heat exchangers to clean fluids typical of hydrocarbon processing, and temperature and pressure limitations are noted.

  20. A Modified Entropy Generation Number for Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    This paper demonstrates the difference between the entropy generation number method proposed by Bejian and the method of entropy generation per unit amount of heat transferred in analyzing the ther-modynamic performance of heat exchangers,points out the reason for leading to the above difference.A modified entropy generation number for evaluating the irreversibility of heat exchangers is proposed which is in consistent with the entropy generation per unit amount of heat transferred in entropy generation analysis.The entropy generated by friction is also investigated.Results show that when the entropy generated by friction in heat exchangers in taken into account,there is a minimum total entropy generation number while the NTU and the ratio of heat capacity rates vary.The existence of this minimum is the prerequisite of heat exchanger optimization.

  1. Discontinuous Operation of Geothermal Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    方肇洪; 刁乃仁; 崔萍

    2002-01-01

    Ground-source heat pump (GSHP) systems for HVAC have aroused more and more interest in China in recent years because of their higher energy efficiency compared with conventional systems. The design and performance simulation of the geothermal heat exchangers is vital to the success of this technology. In GSHP systems, the load of the geothermal heat exchanger varies greatly and is usually discontinuous even during a heating or cooling season. This paper outlines a heat transfer model for geothermal heat exchangers. The model was used to study the influence of the discontinuous operation of the heat pumps on the performance of the geothermal heat exchangers. A simple and practical approach is presented for sizing the geothermal heat exchangers.

  2. A heat transfer model of a horizontal ground heat exchanger

    Science.gov (United States)

    Mironov, R. E.; Shtern, Yu. I.; Shtern, M. Yu.; Rogachev, M. S.

    2016-04-01

    Ground-source heat pumps are gaining popularity in Eastern Europe, especially those which are using the horizontal ground heat exchanger (GHX). Due to the difficulty of accessing GHX after the installation, materials and the quality of the installation must satisfy the very high requirements. An inaccurate calculation of GHX can be the reason of a scarcity of heat power in a crucial moment. So far, there isn't any appropriate mathematical description of the horizontal GHX which takes into account the mutual influence of GHX pipes on each other. To solve this problem we used the temperature wave approach. As a result, a mathematical model which describes the dependence of the heat transfer rate per unit length of the horizontal GHX pipe on the thermal properties of soil, operating time of GHX and the distance between pipes was obtained. Using this model, heat transfer rates per unit length of a horizontal GHX were plotted as functions of the distance between pipes and operating time. The modeling shows that heat transfer rates decreases rapidly with the distance between pipes lower then 2 meters. After the launch of heat pump, heat power of GHX is reduced during the first 20 - 30 days and get steady after that. The obtained results correlate with experimental data. Therefore the proposed mathematical model can be used to design a horizontal GHX with the optimal characteristics, and predict its capability during operation.

  3. Mathematical simulation of heat exchanger working conditions

    Science.gov (United States)

    Gavlas, Stanislav; Ďurčanský, Peter; Lenhard, Richard; Jandačka, Jozef

    2015-05-01

    One of the When designing a new heat exchanger it is necessary to consider all the conditions imposed on the exchanger and its desired properties. Most often the investigation of heat transfer is to find heat surface. When applying exchanger for proposed hot air engine, it will be a counter-flow heat exchanger of gas - gas type. Gas, which transfers the heat will be exhaust gas from the combustion of biomass. An important step in the design and verification is to analyze exchanger designed using numerical methods, the verification of the correctness of design and verification of boundary conditions which include temperatures, flow rates and pressure drops. Due to the fact that the heat transfer in the heat exchanger is a three-dimensional plot and timeindependent, the system is described by partial differential equations that need to be solved by numerical methods.

  4. Multiphysics Numerical Modeling of a Fin and Tube Heat Exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2015-01-01

    ). For the purposes here, only gas flowing over the fin side is simulated assuming constant inner tube wall temperature. The study couples conjugate heat transfer mechanism with turbulent flow in order to describe the temperature and velocity profile. In addition, performance characteristics of the heat exchanger...... design in terms of heat transfer and pressure loss are determined by parameters such as overall heat transfer coefficient, Colburn j-factor, flow resistance factor, and efficiency index. The model provides useful insights necessary for optimization of heat exchanger design....

  5. Direct contact heat exchangers for space

    Science.gov (United States)

    Taussig, R. T.; Thayer, W. J.; Lo, V. C. H.; Sakins, K. M.; Bruckner, A. P.

    1985-06-01

    Direct contact heat exchanger concepts have been investigated for use in space, including droplet vortex heat exchangers, coflowing droplet heat exchangers, electrostatically driven heat exchangers, and belt and disk heat exchangers. These concepts are characterized by a low heat exchanger mass per unit of heat transferred, low pressure losses, high reliability, and compactness in design. Operation in zero-G poses unique problems for those direct contact heat exchangers which require separation of two fluid media after heat transfer is completed. Other problems include maintenance of good heat transfer coefficients in the absence of buoyant forces, exposure of heat transfer media to vacuum conditions for certain applications, and materials compatibility. A preliminary systems analysis indicates the potential for substantial weight reductions in turbine Brayton cycle space power systems for output powers above several MW(e). Based on the status of current technology and the results of this analysis, recommendations are made for the most attractive applications and the R&D required to ready a direct contact heat exchanger for use in space.

  6. Principle of equipartition of entransy dissipation for heat exchanger design

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present work,a principle of equipartition of entransy dissipation(EoED) for heat exchanger design is established,which says that for a heat exchanger design with given heat duty and heat transfer area,the total entransy dissipation rate reaches the minimum when the local entransy dissipation rate is uniformly distributed along the heat exchanger.When the heat transfer coefficient is unfixed,the total entransy dissipation obtained by the EoED principle is less than that obtained by the principle of equipartition of temperature difference(EoTD).Furthermore,the exchanger effectiveness obtained by the EoED principle is larger than that obtained by the EoTD principle.When the heat transfer coefficient is fixed,the EoED principle is equivalent to the EoTD principle.We show that the equipartition of entropy production(EoEP) and EoED principles give rise to difference in entropy generation and entransy dissipation for a heat exchanger optimization design.The discrepancies are caused by distinct features of entropy production minimization and entransy dissipation minimization principles,the former is to optimize the design of heat exchanger by making the lost available work minimum,while the latter is not involved with heat-work conversion.It is found that the entropy generation number is not suitable for evaluating heat exchanger performance,since it directly depends on the inlet and outlet temperatures of working fluids.On the contrary,the entransy dissipation number is not directly related to the inlet and outlet temperatures of working fluids.Therefore,the entransy dissipation number is more suitable for serving as a criterion to evaluate heat exchanger performance.

  7. Analysis of Heat Transfer Properties of Plate-Stick Heat Exchanger(Ⅱ)——The Optimal Structure Design of Heat Exchangers%板棒式换热器传热性能分析(Ⅱ)——换热器结构的优化设计

    Institute of Scientific and Technical Information of China (English)

    邓先和; 徐国想; 张亚君

    2001-01-01

    以单位质量材耗的换热能力最大为目标函数,分析研究了不同雷诺数Re的操作条件下肋棒长度、直径及板厚之间的关系.结果表明:当雷诺数较小时肋棒才可有效地起到强化传热的作用,且随着肋棒直径的减小强化传热作用增强;当板厚为3mm、雷诺数在103~5×103之间时,最佳肋棒长径比为2~3.以上结果可作为板棒式换热器结构优化设计的参考依据.%This paper analyzes the relationships between the constructionparameters of the plate-stick heat exchanger in terms of the diameter and the length of sticks, the thickness of the board and the operation conditions of Re number based on the function of the greatest heat transfer ability per unit weight of heat exchangers. The results indicate that the sticks can be used to strengthen heat transfer at the low Re number and it is enhanced with the stick's diameter decreased. When the thickness of the board is defined as 3 mm and the value of Re number is between 103 and 5 × 103, the optimal ratio of the stick's length and diameter is between 2 and 3. The results can be used for reference as the optimal structure design of the plate-stick exchanger.

  8. Micro tube heat exchangers for Space Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mezzo fabricates micro tube heat exchangers for a variety of applications, including aerospace, automotive racing, Department of Defense ground vehicles, economizers...

  9. Research on Shell-and-Tube Heat Exchanger Optimize Design%管壳式换热器优化设计研究

    Institute of Scientific and Technical Information of China (English)

    吴健

    2015-01-01

    设计一台换热性能优良的管壳式换热器,涉及内容较多,包括初始条件确立、换热管尺寸、壳体类型等信息确定等。本文通过实际应用研究,总结出了换热管尺寸对换热器大小和性能的影响的规律,在借鉴前人研究成果和企业实际应用的基础上,对管壳式换热器的优化设计进行了总结,并提出了一些建议,为换热器设计提供参考。%A better performance of the shell-tube heat exchanger was designed, involving main contents of initial conditions set, heat tube selection, etc. . Through the research of practical application, effect of heat exchange tube size and the size of heat exchanger performance rule was summarized. Based on the results of previous studies, the shell-tube heat exchanger design contents were summarized, and some suggestions were putforward, which can provide reference for the design of heat exchanger.

  10. Bed geometries, fueling strategies and optimization of heat exchanger designs in metal hydride storage systems for automotive applications: A review

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Dornheim, Martin; Sloth, Michael

    2014-01-01

    given to metal hydride storage tanks for light duty vehicles, since this application is the most promising one for such storage materials and has been widely studied in the literature. Enhancing cooling/heating during hydrogen uptake and discharge has found to be essential to improve storage systems......This review presents recent developments for effective heat management systems to be integrated in metal hydride storage tanks, and investigates the performance improvements and limitations of each particular solution. High pressures and high temperatures metal hydrides can lead to different design...

  11. Conjugate heat and mass transfer in heat mass exchanger ducts

    CERN Document Server

    Zhang, Li-Zhi

    2013-01-01

    Conjugate Heat and Mass Transfer in Heat Mass Exchanger Ducts bridges the gap between fundamentals and recent discoveries, making it a valuable tool for anyone looking to expand their knowledge of heat exchangers. The first book on the market to cover conjugate heat and mass transfer in heat exchangers, author Li-Zhi Zhang goes beyond the basics to cover recent advancements in equipment for energy use and environmental control (such as heat and moisture recovery ventilators, hollow fiber membrane modules for humidification/dehumidification, membrane modules for air purification, desi

  12. Probe Measures Fouling As In Heat Exchangers

    Science.gov (United States)

    Marner, Wilbur J.; Macdavid, Kenton S.

    1990-01-01

    Combustion deposits reduce transfer of heat. Instrument measures fouling like that on gas side of heat exchanger in direct-fired boiler or heat-recovery system. Heat-flux probe includes tube with embedded meter in outer shell. Combustion gases flow over probe, and fouling accumulates on it, just as fouling would on heat exchanger. Embedded heat-flow meter is sandwich structure in which thin Chromel layers and middle alloy form thermopile. Users determine when fouling approaches unacceptable levels so they schedule cleaning and avoid decreased transfer of heat and increased drop in pressure fouling causes. Avoids cost of premature, unnecessary maintenance.

  13. Numerical Analysis of Heat Transfer and Fluid Flow in Heat Exchangers with Emphasis on Pin Fin Technology

    OpenAIRE

    2012-01-01

    One of the most important industrial processes is heat transfer, carried out by heat exchangers in single and multiphase flow applications. Despite the existence of well-developed theoretical models for different heat transfer mechanisms, the expanding need for industrial applications requiring the design and optimization of heat exchangers, has created a solid demand for experimental work and effort. This thesis concerns the use of numerical approaches to analyze and optimize heat transfer a...

  14. Development of high effectiveness droplet heat exchangers

    Science.gov (United States)

    Thayer, W. J., III; Sekins, K. M.; Bruckner, A. P.

    1985-04-01

    An experimental and analytical investigation has been carried out to assess the feasibility of developing high effectiveness, high temperature droplet heat exchangers and to identify practical applications for this type of direct contact heat exchanger. The droplet heat exchanger (DHX) concept studies uses a counterflowing gas and droplet configuration, uniformly sized droplets or particles, and a uniform dispersion of droplets in gas to achieve high heat exchanger effectiveness. Direct contact between the heat transfer media eliminates the solid heat transfer surfaces that are used in conventional heat exchangers and is expected to make very high temperature heat transfer practical. Low temperature simulation tests and analysis have been used to demonstrate that uniformly sized droplets can be generated over a wide range of fluid properties and operating conditions appropriate for high temperature droplet heat exchanger applications. One- and two-dimensional, two-phase flow and heat transfer computer models have been developed and used to characterize both individual component configurations and overall DHX heat transfer rates and effectiveness. The computer model and test data began to diverge as the operating pressure was increased, indicating a need for more general transport rate correlations and a better understanding of the two-phase flows that govern DHX operation.

  15. Heat Exchanger Lab for Chemical Engineering Undergraduates

    Science.gov (United States)

    Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.

    2015-01-01

    Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…

  16. Heat Exchanger Lab for Chemical Engineering Undergraduates

    Science.gov (United States)

    Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.

    2015-01-01

    Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…

  17. Entropy resistance analyses of a two-stream parallel flow heat exchanger with viscous heating

    Institute of Scientific and Technical Information of China (English)

    Cheng Xue-Tao; Liang Xin-Gang

    2013-01-01

    Heat exchangers are widely used in industry,and analyses and optimizations of the performance of heat exchangers are important topics.In this paper,we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process.With this concept,a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed.It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger,while the minimizations of entropy generation rate,entropy generation numbers,and revised entropy generation number do not always.

  18. Heat exchanger device and method for heat removal or transfer

    Science.gov (United States)

    Koplow, Jeffrey P [San Ramon, CA

    2012-07-24

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  19. Heat exchanger device and method for heat removal or transfer

    Science.gov (United States)

    Koplow, Jeffrey P

    2013-12-10

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  20. Testing and plugging power plant heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sutor, F. [Expando Seal Tools, Inc., Montgomeryville, PA (United States)

    1994-12-31

    Heat Exchanger tubes fail for any number of reasons including but certainly not limited to the cumulative effects of corrosion, erosion, thermal stress and fatigue. This presentation will attempt to identify the most common techniques for determining which tubes are leaking and then introduce the products in use to plug the leaking tubes. For the sake of time I will limit the scope of this presentation to include feedwater heaters and secondary system heat exchangers such as Hydrogen Coolers, Lube Oil Coolers, and nuclear Component Cooling Water, Emergency Cooling Water, Regenerative Heat Recovery heat exchangers.

  1. Improved ceramic heat exchanger materials

    Science.gov (United States)

    Rauch, H. W.

    1980-01-01

    The development and evaluation of materials for potential application as heat exchanger structures in automotive gas turbine engines is discussed. Test specimens in the form of small monolithic bars were evaluated for thermal expansion and dimensional stability before and after exposure to sea salt and sulfuric acid, followed by short and long term cycling at temperatures up to 1200 C. The material finally selected, GE-7808, consists of the oxides, ZrO2-MgO-Al2O3-S1O2, and is described generically as ZrMAS. The original version was based on a commercially available cordierite (MAS) frit. However, a clay/talc mixture was demonstrated to be a satisfactory very low cost source of the cordierite (MAS) phase. Several full size honeycomb regenerator cores, about 10.2 cm thick and 55 cm diameter were fabricated from both the frit and mineral versions of GE-7808. The honeycomb cells in these cores had rectangular dimensions of about 0.5 mm x 2.5 mm and a wall thickness of approximately 0.2 mm. The test data show that GE-7808 is significantly more stable at 1100 C in the presence of sodium than the aluminosilicate reference materials. In addition, thermal exposure up to 1100 C, with and without sodium present, results in essentially no change in thermal expansion of GE-7808.

  2. 40 CFR 63.1409 - Heat exchange system provisions.

    Science.gov (United States)

    2010-07-01

    ... locations where the cooling water enters and exits each heat exchanger or any combination of heat exchangers.... (iii) For samples taken at the entrance and exit of each heat exchanger or any combination of heat exchangers, the entrance is the point at which the cooling water enters the individual heat exchanger...

  3. 基于改进型粒子群算法的板式换热器优化设计%Plate Heat Exchanger Optimization Design Based on Improved Particle Swarm Algorithm

    Institute of Scientific and Technical Information of China (English)

    余静飞; 姜波; 胡申华

    2013-01-01

    In the optimization process of plate heat exchanger(PHE), many variables were involved, there were boundary constraints for some of these variables, such as flow rate. In this article,starting from the effect of the flow rate on heat transfer and pressure, thermodynamic model was built. Improvements have been made on the basis of elementary particle swarm optimization. The improved particle swarm algorithm was used in the plate heat exchanger optimization design, successful resolved the problem of plate heat exchanger cost optimization design with a constrained flow rate.%在板式换热器优化设计过程中,涉及到的变量较多,对有些变量的取值范围有界限约束,比如流速。本文从流速对换热效果和压力的影响出发,建立热力学模型,在基本粒子群算法上做了改进,利用此改进的粒子群算法对板式换热器流速受限的情况进行优化设计,解决了板式换热器中流速受到约束时的成本优化问题。

  4. Optimization design of shell-and-tube heat exchangers based on genetic algorithm%应用遗传算法优化设计壳管式换热器

    Institute of Scientific and Technical Information of China (English)

    李夔宁; 张继广; 李进; 郭军峰

    2011-01-01

    针对壳管式换热器传统设计方法繁杂且结果又不能满足最佳经济费用的缺点,引入遗传算法对壳管式换热器进行设计。建立了相应的数学模型并以设备总费用为目标函数,对换热器进行优化设计。利用遗传算法智能及多点搜索等特性,不断地迭代优化变量,在优化变量值和约束条件范围内,得到最小目标函数的设计结果。采用了2个实际算例进行测试,结果显示在满足换热性能的前提下,优化后总费用都有降低,降幅分别为18.2%,7.98%。%Genetic algorithm(GA) is used for the optimal design of shell-and-tube heat exchangers due to the fact that traditional designs for shell-and-tube heat exchangers are complicated and uneconomical.To optimize the design of heat exchangers,mathematical models are established and the total costs are used as the objective function.Taking advantage of GA's intelligent and multi-searching characteristics,researchers continuously iterate optimization variables and then obtain the minimum objective function of the design results within the optimal variable values and constraints.Two practical heat exchangers are used to test the research results.The Optimization results show that the optimized total costs have decreased by 18.2% and 7.98% respectively,which can also satisfy the heat transfer performance.Moreover,the results show that the design based on GA for shell-and-tube heat exchangers can significantly improve the economic efficiency of heat exchangers and thus can be applied to engineering practice.

  5. Structure Parameter Optimization of Air-water Dual-source Compound Heat-exchanger%空气-水双热源复合换热器结构参数优化

    Institute of Scientific and Technical Information of China (English)

    张超; 董家昀; 赵晓丹; 周光辉

    2012-01-01

    空气-水双热源复合换热器是太阳能-空气双热源复合热泵系统的核心部件,空气-水双热源复台换热器的结构参数对空气-水双热源复合换热器的换热性能以及太阳能-空气双热源复合热泵的系统性能具有重要影响.建立了太阳能-空气双热源复合热泵系统的数学模型,利用数学模拟的方法研究了空气-水双热源复合换热器结构参数对热泵系统能效比的影响,并确定了模拟工况下换热器结构参数的优化方案.%The air-water dual-source compound heat-exchanger is the key component of the solar-air dual-source compound heat pump system. The heat-exchanging performance of the air-water dual-source compound heat-exchanger and the system performance of the solar-air dual-source compound heat pump system are largely depended on the structure parameter of the air-water dual-source compound heat-exchanger. The mathematic model of the solar-air dual-source compound heat pump system has been established. The mathematic simulation method has been used to study the effect of the structure parameters of air-water dual-source compound heat-exchanger on the energy-efficiency ratio of the solar-air dual-source compound heat pump system, and the optimization scheme of the structure parameters under the simulating condition have been determined.

  6. Analysis of a Flooded Heat Exchanger

    Science.gov (United States)

    Fink, Aaron H.; Luyben, William L.

    2015-01-01

    Flooded heat exchangers are often used in industry to reduce the required heat-transfer area and the size of utility control valves. These units involve a condensing vapor on the hot side that accumulates as a liquid phase in the lower part of the vessel. The heat transfer occurs mostly in the vapor space, but the condensate becomes somewhat…

  7. A Review on Heat Transfer Improvent of Plate Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Abhishek Nandan

    2015-03-01

    Full Text Available Plate heat exchanger has found a wide range of application in various industries like food industries, chemical industries, power plants etc. It reduces the wastage of energy and improves the overall efficiency of the system. Hence, it must be designed to obtain the maximum heat transfer possible. This paper is presented in order to study the various theories and results given over the improvement of heat transfer performance in a plate heat exchanger. However, there is still a lack in data and generalized equations for the calculation of different parameters in the heat exchanger. It requires more attention to find out various possible correlations and generalized solutions for the performance improvement of plate heat exchanger.

  8. Investigation of Heat Exchange Efficiency in the Heat Exchanger Waste Heat Recovery with Granular Nozzle

    Directory of Open Access Journals (Sweden)

    Boshkova I.L.

    2016-12-01

    Full Text Available The article analyzes the characteristics of the heat transfer process between the dispersed and gaseous medium for the moving and fixed layer of particulate material. The methods of calculus of thermal and hydraulic regimes of heat exchangers with a dense layer of particles were elaborated. The results of experimental studies of the process of heating of different kinds of granular material, intended for use as a nozzle in the recuperative heat exchanger. The influence of the height of heating chamber, the particle diameter on the output temperature of the granular material has been determined. The dependence of the temperature of the gas and solid components of the height of the nozzle has been presented.

  9. 一种回转窑余热回收用集热器的实验研究及其结构优化%Experimental measurement and structure optimization of heat recovery exchangers on rotary kilns

    Institute of Scientific and Technical Information of China (English)

    殷谦; 杜文静; 纪兴林; 程林

    2016-01-01

    A novel heat recovery exchanger installed on the rotary kiln shell surface is proposed in this paper. The heat recovery exchanger contains water tubes and coiled pipes, which function as the radiative and the convective heat transfer surfaces, respectively. Numerical studies and experimental measurements are carried out to investigate the heat transfer characteristics of the heat exchanger. Several optimization models are proposed with the heat transfer area, the pressure drop and the modified entropy generation numbers set as the objective functions. The models describe the relation between the heat transfer rates and structural parameters of the heat recovery exchanger, i.e. the tube length, the tube numbers and the tube diameter. The optimized design parameters are obtained by applying the genetic algorithm toolbox in Matlab. The results indicate that the optimized heat transfer areas of water tubes and coiled pipes are decreased by 15% and 20%, respectively. The corresponding pressure drop is significantly decreased after optimization. In the optimization process, the modified entropy generation numbers are decreased due to fluid friction, while the modified entropy generation numbers remain unchanged due to heat transfer.%减少回转窑表面的散热损失对冶金、化工等高耗能行业的节能减排具有重要意义。针对现有窑表面集热器回收效率较低的现状,提出了一种新型集热器,并通过实验测量与数值计算分析了其换热性能。建立了集热器换热量与管长、管径及管子数等结构参数的数学关系,分别以换热面积、进出口压降以及改进的熵产数为优化目标,利用遗传算法分别对其进行了结构设计,结果表明,优化后集热器的辐射换热所需的换热面积减小15%,对流换热所需的换热面积减少20%左右。优化后两种形式的换热面所消耗的泵功明显减少。优化后集热器的传热熵产数与

  10. Comparison of heat transfer efficiency between heat pipe and tube bundles heat exchanger

    Directory of Open Access Journals (Sweden)

    Wu Zhao-Chun

    2015-01-01

    Full Text Available A comparison of heat transfer efficiency between the heat pipe and tube bundles heat exchanger is made based on heat transfer principle and the analysis of thermal characteristics. This paper argues that although heat pipe has the feature of high axial thermal conductivity, to those cases where this special function of heat transfer is unnecessary, heat pipe exchanger is not a high efficient heat exchanger when it is just used as a conventional heat exchanger in the industrial fields. In turn, there are some deficiencies for heat pipe exchanger, such as complicated manufacturing process, critical requirements for manufacturing materials, etc. which leads to a higher cost in comparison to a tubular heat exchanger. Nonetheless, due to its diverse structural features and extraordinary properties, heat pipe exchanger still has wide applications on special occasions.

  11. Research of Spined Heat-Exchanging Pipes

    Directory of Open Access Journals (Sweden)

    Akulov Kirill

    2016-01-01

    Full Text Available Work is devoted to a research of spined heat-exchanging pipes that are assumed to use in air-cooler exchangers (ACE. The proposed new geometry of finning allows intensifying heat exchange and improving the efficiency of air coolers. It is caused by the increased area of finned surface with a value of finning ratio (the ratio of the area of the smooth pipe to a finned one to 42.7, while in the commercially available ACE, the figure is 22. Besides, the geometrical arrangement of the pin fins turbulizes the airflow. It should be mentioned that an easier method of manufacturing of heat exchanging pipes is proposed to use, which will reduce their costs. The proposed heat exchange pipes are made by winding cut aluminum strip to the supporting pipe or stretching stamped blanks on it. To increase the efficiency of the heat exchange surface pin fins should be as thin and long as possible; however, their strength should be sufficient for deformation-free operation. Fins should be staggered to maximize the distance between them. Spined heat-exchange pipes are designed to operate in a commercially produced ACE and their service is carried out similarly to commercially produced transversely finned pipes.

  12. Mathematical Modeling of Spiral Heat Exchanger

    OpenAIRE

    Probal Guha , Vaishnavi Unde

    2014-01-01

    Compact Heat Exchangers (CHEs) are increasingly being used on small and medium scale industries. Due to their compact size and efficient design, they facilitate more efficient heat transfer. Better heat transfer would imply lesser fuel consumption for the operations of the plant, giving improvement to overall efficiency. This reduction in consumption of fuel is a step towards sustainable development. This report exclusively deals with the study the spiral heat ...

  13. Enhancement of Heat Exchanger Control Using Improved PID Controller

    Directory of Open Access Journals (Sweden)

    Gopalakrishna G.

    2009-08-01

    Full Text Available The Proportional, Integral and Derivative (PID controllers are widely used in industrial applications. Their popularity comes from their robust performance and also from their functional simplicity. Temperature control of double tube heat exchanger system is presented and ant colony algorithm for optimizing PID parameters of temperature controller is presented in this paper on the basis of conventional PID controller. Temperature controller based on ant colony optimization for double tube heat exchanger is designed. Simulation results show that, for the case of heat exchanger system, ACO-PID is good model and generalize well. The closed loop unit step response obtained with the proposed PID compares favorably with the one achieved using a conventional PID controller with dynamic closed-loop simulation. More important, the proposed approach takes a fraction of the time spent by the standard technique, without the need of perturbing the closed-loop system.

  14. Lightweight Thermal Storage Heat Exchangers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR proposal aims to develop thermal energy storage heat exchangers that are significantly lighter and higher conductance than the present art which involves...

  15. Optimization of existing heat-integrated refinery distillation systems

    Energy Technology Data Exchange (ETDEWEB)

    Gadalla, M.; Jobson, M.; Smith, R.

    2003-01-01

    Existing refinery distillation systems are highly energy-intensive, and have complex column configurations that interact strongly with the associated heat exchanger network. An optimization approach is developed for existing refinery distillation processes. The optimization framework includes shortcut models developed for the simulation of the existing distillation column, and a retrofit shortcut model for the heat exchanger network. The existing distillation process is optimized by changing key operating parameters, while simultaneously accounting for hydraulic limitations and the design and the performance of the existing heat exchanger network. A case study shows that a reduction in energy consumption and operating costs of over 25% can be achieved. (Author)

  16. Performance Prediction of Cross-finned Tube Heat Exchangers

    Science.gov (United States)

    Kondou, Chieko; Senshu, Takao; Matsumura, Kenji; Oguni, Kensaku

    An important issue in heat pumps is increasing their efficiency, in order to achieve a significant optimization for heat exchangers. Techniques to simulate the flow length averaged heat transfer coefficient and static pressure drop through the flow passage are presented in this paper. In addition, an analytical evaluation of the cost reduction for a cross-fined tube heat exchanger of outdoor heat pump units is instantiated. The dimensionless factors, Colburn's factor j and Fanning's friction factor f, express the heat transfer performance and frictional characteristics, as a function of Reynolds number. These depend on slit possession, an original parameter used in this study. Further, this paper describes an approximate expression of the fin efficiency, which can be used for to survey the fin parameters. The above three concepts were necessary to forecast the performance on the airside. In the results, the cost minimum point was obtained with a comparable performance.

  17. Structural optimization of converging-diverging tube based on heat transfer enhancement for self-support rectangle heat exchanger%矩形自支撑缩放管换热器强化传热的结构优化

    Institute of Scientific and Technical Information of China (English)

    焦凤; 邓先和

    2013-01-01

    For the new heat exchanger,self-support rectangle converging-diverging tube bundle heat exchanger,3-D numerical simulations were performed with FLUENT software for turbulent heat transfer and fluid flow characteristics in the heat exchanger.To obtain the optimal structure of converging-diverging tube,the rib length (l) and height (h) were examined while retaining converging length ratio.The effects on heat transfer performance of tube side,shell side and whole heat exchanger were studied.With constant rib length,the effect of rib height was examined.The numerical results indicate that smaller rib length and larger rib height lead to better performance of heat transfer and larger flow resistance on both shell side and tube side.Performance evaluation criteria (η) is adopted to evaluate the overall heat transfer performance.When l=16.5 mm,ηis the largest on the shell side,while when l=9 mm it is the largest on the tube side.For rib length of 15 mm,the overall heat transfer performance is the best when h =0.5 mm on the shell side,while it is the best when h=1.25 mm on the tube side.The reason is that the recirculation region increases with the increase of rib length and height on both shell side and tube side.With the increase of recirculation region,the friction in the channel increases.However,the recirculation region reduces the average intersection angle between the velocity vector and the temperature gradient,which is one of the essential factors influencing heat transfer performance.For rib length of 15 mm and rib height of 0.75 mm,the performance evaluation criteria η of the whole heat exchanger is 1.136-1.155against the Reynolds number of shell side in the range of 27900-41900 as compared with the smooth tube bundle heat exchanger.%在新型换热器——矩形自支撑缩放管换热器的基础上,通过FLUENT软件利用三维数值模拟的方法分别研究在缩放段长度比例保持不变的情况下,缩放节距及缩放肋高对换

  18. Stirling Engine With Radial Flow Heat Exchangers

    Science.gov (United States)

    Vitale, N.; Yarr, George

    1993-01-01

    Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

  19. Brayton-cycle heat exchanger technology program

    Science.gov (United States)

    Killackey, J. J.; Coombs, M. G.; Graves, R. F.; Morse, C. J.

    1976-01-01

    The following five tasks designed to advance this development of heat exchanger systems for close loop Brayton cycle power systems are presented: (1) heat transfer and pressure drop data for a finned tubular heat transfer matrix. The tubes are arranged in a triangular array with copper stainless steel laminate strips helically wound on the tubes to form a disk fin geometry; (2) the development of a modularized waste heat exchanger. Means to provide verified double containment are described; (3) the design, fabrication, and test of compact plate fin heat exchangers representative of full scale Brayton cycle recuperators; (4) the analysis and design of bellows suitable for operation at 1600 F and 200 psia for 1,000 cycles and 50,000 hours creep life; and (5) screening tests used to select a low cost braze alloy with the desirable attributes of a gold base alloy. A total of 22 different alloys were investigated; the final selection was Nicrobraz 30.

  20. Numerical Simulation of Different Models of Heat Pipe Heat Exchanger Using AcuSolve

    Directory of Open Access Journals (Sweden)

    Zainal Nurul Amira

    2017-01-01

    Full Text Available In this paper, a numerical simulation of heat pipe heat exchanger (HPHE is computed by using CFD solver program i.e. AcuSolve. Two idealized model of HPHE are created with different variant of entry’s dimension set to be case 1 and case 2. The geometry of HPHE is designed in SolidWorks and imported to AcuSolve to simulate the fluid flow numerically. The design of HPHE is the key to provide a heat exchanger system to work proficient as expected. Finally, the result is used to optimize and improving heat recovery systems of the increasing demand for energy efficiency in industry.

  1. Simulation and optimization of shell-tube heat exchanger for CO2 removal%脱碳工艺中管壳式换热器的模拟及优化

    Institute of Scientific and Technical Information of China (English)

    张庆印; 徐晓辉; 陈健; 王晓光

    2015-01-01

    运用Aspen Plus对脱碳工艺中管壳式换热器进行模拟和优化,设计出符合国家标准的管壳式换热器.设计和模拟过程中,充分考虑各股物流的相态变化,利用Property Analysis模块生成物料相图,分析换热过程中的相变情况.结合手工计算,采用HEATER和HEATX模块简捷计算所需换热面积,初选出符合国家标准的管壳式换热器.在换热面积裕量及压力降许可范围内,调整参数变量,优化换热器.模拟优化结果表明:经过调整优化后,相同热负荷条件下,换热器实际换热面积节省21.4%.模拟和优化过程降低了实验费用,提高了工作效率.%Shell-tube heat exchanger for carbon dioxide removal is simulated and optimized by Aspen Plus. The shell-tube heat exchanger that accord with national standards is designed. During the design and simulation process, the phase transition of the material is fully considered. Phase diagram is calculated by Property Analysis module and the phase transition process is analyzed. Coupled with the manual calculation, HEATER and HEATX shortcut module of Aspen Plus are carried out to calculate the acquired exchanger area. The shell-tube heat exchanger that accord with the national standard is first selected. Within the limitations of the percent over design of exchanger area and the pressure drop, the variables are adjusted to optimize the shell-tube heat exchanger. The actual exchanger area decrease 21.4%!on the same heat duty after optimization. The simulation and optimization will greatly reduce the cost of the experiment and improve the working efficiency.

  2. Research of heat exchange rate of the pulsating heat pipe

    Directory of Open Access Journals (Sweden)

    Kravets V. Yu.

    2010-02-01

    Full Text Available Given article presents experimental research of heat transfer characteristics of the pulsating heat pipe (PHP which consists of seven coils with 1 mm inner diameter. Water was used as the heat carrier. PHP construction, measuring circuit and research technique are presented. It is shown that under PHP functioning there are two characteristic modes of operation, which can be distinguished by values of thermal resistance. PHP heat exchange features are disclosed.

  3. The Temperature Control Optimization and Application for Tube-shell Heat Exchanger%管壳式换热器温度控制方式的优化与应用

    Institute of Scientific and Technical Information of China (English)

    高秀娟

    2013-01-01

    管壳式换热器是化工行业中应用最广泛的换热设备结构形式。论文对比了管壳式换热器一般温度控制方案的优缺点,并结合实际情况对温度控制方式进行优化和应用。结果表明,优化后的温度控制方案能克服大波动对系统稳定性的影响,非常适用于大型精馏塔蒸汽换热器的温度控制,对其他工业过程的温度控制具有借鉴意义。%The tube-shell heat exchanger is the most widely used structure of heat transfer equipment in chemical industry. This paper compares the advantages and disadvantages of two general temperature control schemes in the tube-shell heat exchanger, and makes the tempera-ture control optimization and application according to the actual situation. The results show that the optimized temperature control solution can overcome the big fluctuation on system stability, which is ideal for temperature control of steam heat exchanger in huge distillation column, this paper also can be used for reference in the temperature control in other industrial processes.

  4. Numerical Modeling of Fin and Tube Heat Exchanger for Waste Heat Recovery

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    associates conjugate heat transfer phenomenon with the turbulent flow to describe the variable temperature and velocity profile. The performance of heat exchanger design is investigated in terms of overall heat transfer coefficient, Nusselt number, Colburn j-factor, flow resistance factor, and efficiency......In the present work, multiphysics numerical modeling is carried out to predict the performance of a liquid-gas fin and tube heat exchanger design. Three-dimensional (3D) steady-state numerical model using commercial software COMSOL based on finite element method (FEM) is developed. The study...... between fin and tube. The present numerical model predicts the performance of the heat exchanger design, therefore, can be applied to existing waste heat recovery systems to improve the overall performance with optimized design and process-dependent parameters....

  5. Observer-based monitoring of heat exchangers.

    Science.gov (United States)

    Astorga-Zaragoza, Carlos-Manuel; Alvarado-Martínez, Víctor-Manuel; Zavala-Río, Arturo; Méndez-Ocaña, Rafael-Maxim; Guerrero-Ramírez, Gerardo-Vicente

    2008-01-01

    The goal of this work is to provide a method for monitoring performance degradation in counter-flow double-pipe heat exchangers. The overall heat transfer coefficient is estimated by an adaptive observer and monitored in order to infer when the heat exchanger needs preventive or corrective maintenance. A simplified mathematical model is used to synthesize the adaptive observer and a more complex model is used for simulation. The reliability of the proposed method was demonstrated via numerical simulations and laboratory experiments with a bench-scale pilot plant.

  6. Phase Change Material Heat Exchanger Life Test

    Science.gov (United States)

    Lillibridge, Sean; Stephan, Ryan

    2009-01-01

    Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The IR environment of the space craft varies drastically from the light side to the dark side of the moon. The result is a situation where a radiator sized for the maximal heat load in the most adverse situation is subject to freezing on the dark side of the orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor," storing thermal energy when there is too much being produced by the space craft to reject to space, and then feeding that energy back into the thermal loop when conditions are more favorable. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration LLO missions. In order to validate the performance of PCM Heat Exchangers, a life test is being conducted on four n-Pentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 melt-freeze cycles will be performed.

  7. Near Field Investigation of Borehole Heat Exchangers

    OpenAIRE

    2015-01-01

    As an alternative and renewable energy source, the shallow geothermal energy evolving as one of the most popular energy source due to its easy accessibility and availability worldwide, and the ground source heat pump (GSHP) systems are the most frequent applications for extracting the energy from the shallow subsurface. As the heat extraction capacity of the GSHP system applications arises, the design of the borehole heat exchangers (BHE), which is the connected part of the system in the grou...

  8. A fundamentally new approach to air-cooled heat exchangers.

    Energy Technology Data Exchange (ETDEWEB)

    Koplow, Jeffrey P.

    2010-01-01

    We describe breakthrough results obtained in a feasibility study of a fundamentally new architecture for air-cooled heat exchangers. A longstanding but largely unrealized opportunity in energy efficiency concerns the performance of air-cooled heat exchangers used in air conditioners, heat pumps, and refrigeration equipment. In the case of residential air conditioners, for example, the typical performance of the air cooled heat exchangers used for condensers and evaporators is at best marginal from the standpoint the of achieving maximum the possible coefficient of performance (COP). If by some means it were possible to reduce the thermal resistance of these heat exchangers to a negligible level, a typical energy savings of order 30% could be immediately realized. It has long been known that a several-fold increase in heat exchanger size, in conjunction with the use of much higher volumetric flow rates, provides a straight-forward path to this goal but is not practical from the standpoint of real world applications. The tension in the market place between the need for energy efficiency and logistical considerations such as equipment size, cost and operating noise has resulted in a compromise that is far from ideal. This is the reason that a typical residential air conditioner exhibits significant sensitivity to reductions in fan speed and/or fouling of the heat exchanger surface. The prevailing wisdom is that little can be done to improve this situation; the 'fan-plus-finned-heat-sink' heat exchanger architecture used throughout the energy sector represents an extremely mature technology for which there is little opportunity for further optimization. But the fact remains that conventional fan-plus-finned-heat-sink technology simply doesn't work that well. Their primary physical limitation to performance (i.e. low thermal resistance) is the boundary layer of motionless air that adheres to and envelops all surfaces of the heat exchanger. Within this

  9. Thermal design of spiral heat exchangers and heat pipes through global best algorithm

    Science.gov (United States)

    Turgut, Oğuz Emrah; Çoban, Mustafa Turhan

    2017-03-01

    This study deals with global best algorithm based thermal design of spiral heat exchangers and heat pipes. Spiral heat exchangers are devices which are highly efficient in extremely dirty and fouling process duties. Spirals inherent in design maintain high heat transfer coefficients while avoiding hazardous effects of fouling and uneven fluid distribution in the channels. Heat pipes have wide usage in industry. Thanks to the two phase cycle which takes part in operation, they can transfer high amount of heat with a negligible temperature gradient. In this work, a new stochastic based optimization method global best algorithm is applied for multi objective optimization of spiral heat exchangers as well as single objective optimization for heat pipes. Global best algorithm is easy-to-implement, free of derivatives and it can be reliably applied to any optimization problem. Case studies taken from the literature approaches are solved by the proposed algorithm and results obtained from the literature approaches are compared with thosed acquired by GBA. Comparisons reveal that GBA attains better results than literature studies in terms of solution accuracy and efficiency.

  10. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood...

  11. 40 CFR 63.104 - Heat exchange system requirements.

    Science.gov (United States)

    2010-07-01

    ... heat exchange system or at locations where the cooling water enters and exits each heat exchanger or any combination of heat exchangers. (i) For samples taken at the entrance and exit of recirculating... manufacturing process units. (iii) For samples taken at the entrance and exit of each heat exchanger or...

  12. Numerical study of heat transfer characteristics in BOG heat exchanger

    Science.gov (United States)

    Yan, Yan; Pfotenhauer, John M.; Miller, Franklin; Ni, Zhonghua; Zhi, Xiaoqin

    2016-12-01

    In this study, a numerical study of turbulent flow and the heat transfer process in a boil-off liquefied natural gas (BOG) heat exchanger was performed. Finite volume computational fluid dynamics and the k - ω based shear stress transport model were applied to simulate thermal flow of BOG and ethylene glycol in a full-sized 3D tubular heat exchanger. The simulation model has been validated and compared with the engineering specification data from its supplier. In order to investigate thermal characteristics of the heat exchanger, velocity, temperature, heat flux and thermal response were studied under different mass flowrates in the shell-side. The shell-side flow pattern is mostly determined by viscous forces, which lead to a small velocity and low temperature buffer area in the bottom-right corner of the heat exchanger. Changing the shell-side mass flowrate could result in different distributions of the shell-side flow. However, the distribution in the BOG will remain in a relatively stable pattern. Heat flux increases along with the shell-side mass flowrate, but the increase is not linear. The ratio of increased heat flux to the mass flow interval is superior at lower mass flow conditions, and the threshold mass flow for stable working conditions is defined as greater than 0.41 kg/s.

  13. Research of the heat exchanging processes running in the heating and hot water supply loops of the coil heat exchangers

    Directory of Open Access Journals (Sweden)

    Ірина Геннадіївна Шитікова

    2016-11-01

    Full Text Available The fuel-energy complex research has made it possible to disclose a huge power-saving potential in the municipal heat-and-power engineering. Power-and-resource-saving units and systems are becoming extremely urgent because of the power engineering crisis expansion. The self-adjusting heat supply system from the individual heating points with the heat-accumulating units and coil heat exchangers for independent heating and water supply systems has been examined. Coil heat exchangers are used in municipal heating for heat transfer (e.g. geothermal waters for the independent mains of the heating and hot water supply systems. The heat engineering calculation of the heating and accumulating unit with the coil heat exchanger for independent heat supply systems from individual heater was performed and experimental data were received at the experimental industrial unit under the laboratory conditions. The peculiarities of the flows in the intertubular space, their influence on the heat exchange and temperatures of the first and intermediate mains have been shown. It is important to know the processes running inside the apparatus to be able to improve the technical characteristics of the three-loop coil heat exchanger. The task solution will make it possible to save the materials consumption for the three-loop coil heat exchangers in the future

  14. RECITAL SCRUTINY ON TUBE-INTUBE COMPACT HEAT EXCHANGERS

    OpenAIRE

    V.NATARAJAN,; Dr. P. Senthil Kumar

    2011-01-01

    This paper focused on the investigational cram of the recital characteristics of tube-in-tube compact heat exchangers. Experiments are conducted in the compact heat exchangers with R-134a and liquefiedpetroleum gas. The effectiveness of the heat exchangers was calculated using the experiment data and it was found that the effectiveness of heat exchanger-1 is above 75 and heat exchanger-2 is above 84% for R-134a.The effectiveness of heat exchanger-1 is about 60% and heat exchanger-2 is about 8...

  15. Optimisation of Double Pipe Helical Tube Heat Exchanger and its Comparison with Straight Double Tube Heat Exchanger

    Science.gov (United States)

    Kareem, Rashid

    2017-10-01

    Optimization of double pipe helical coil heat exchanger with various optimizing parameters and its comparison with double pipe straight tube are the prime objectives of this paper. Numerical studies were performed with the aid of a commercial computational fluid dynamics package ANSYS FLUENT 14. In this paper the double pipe helical coil is analysed under turbulent flow conditions for optimum heat exchanger properties. The parameters used for optimization are cross-sectional shape and taper angles. Optimization analysis is being carried out for finding best cross sectional shape of heat exchanger coils by using rectangular, square, triangular and circular cross-sections. The tapered double pipe helical coil is then analysed for best heat transfer and pressure drop characteristics by varying the angle of taper. Finally, an optimum coil on the basis of all the analysis is selected. This optimized double pipe helical coil is compared with double pipe straight tube of equivalent cross-sectional area and length as that of unwounded length of double pipe helical coil.

  16. Ecological optimization for general heat engines

    Science.gov (United States)

    Long, Rui; Liu, Wei

    2015-09-01

    We conducted an analysis of efficiency and its bounds for general heat engines under the maximum ecological criterion. For generality, both nonisothermal heat-exchanging processes and internal dissipation were taken into consideration. When the product of the internal dissipation and the heat capacity ratio is one, the efficiency under the maximum ecological criterion is the same as that of the irreversible Carnot model. However, the efficiencies have different physical meanings and optimization spaces. Furthermore, the efficiency is independent of the time it takes to complete each process and the heat conductance. For other situations, numerical calculations were conducted to investigate the parameters' effects on optimal efficiency. When the dimensionless contact times approach zero, the irreversible Carnot model is recovered. The general upper and lower bounds of optimal efficiency are obtained by applying the asymmetric heat capacity ratio limits when the dimensionless contact times approach infinity. In addition, the efficiency of general endoreversible heat engines was investigated. The efficiency bounds of different real-life heat engines under the maximum ecological criterion are proposed.

  17. Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19

    The objective of this project is to produce the necessary data to evaluate the performance of the supercritical carbon dioxide cycle. The activities include a study of materials compatibility of various alloys at high temperatures, the heat transfer and pressure drop in compact heat exchanger units, and turbomachinery issues, primarily leakage rates through dynamic seals. This experimental work will serve as a test bed for model development and design calculations, and will help define further tests necessary to develop high-efficiency power conversion cycles for use on a variety of reactor designs, including the sodium fast reactor (SFR) and very high-temperature gas reactor (VHTR). The research will be broken into three separate tasks. The first task deals with the analysis of materials related to the high-temperature S-CO{sub 2} Brayton cycle. The most taxing materials issues with regard to the cycle are associated with the high temperatures in the reactor side heat exchanger and in the high-temperature turbine. The system could experience pressures as high as 20MPa and temperatures as high as 650°C. The second task deals with optimization of the heat exchangers required by the S-CO{sub 2} cycle; the S-CO{sub 2} flow passages in these heat exchangers are required whether the cycle is coupled with a VHTR or an SFR. At least three heat exchangers will be required: the pre-cooler before compression, the recuperator, and the heat exchanger that interfaces with the reactor coolant. Each of these heat exchangers is unique and must be optimized separately. The most challenging heat exchanger is likely the pre-cooler, as there is only about a 40°C temperature change but it operates close to the CO{sub 2} critical point, therefore inducing substantial changes in properties. The proposed research will focus on this most challenging component. The third task examines seal leakage through various dynamic seal designs under the conditions expected in the S-CO{sub 2} cycle

  18. Effects of winglets to augment tube wall heat transfer in louvered fin heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Paul A.; Thole, Karen A. [Virginia Tech, Blacksburg, VA (United States). Mechanical Engineering Department

    2006-10-15

    The louvered fin heat exchanger, a type of compact heat exchanger, has been used heavily in the automotive and air conditioning industries for the last several decades. The majority of past research, aimed towards improving louvered fin exchanger efficiency, has focused on optimizing various parameters of the louvered fin. The experimental study presented in this paper concentrates instead on augmenting the heat transfer along the tube wall of the compact heat exchanger through the use of winglets placed on the louvers. The experiments were completed on a 20 times scaled model of an idealized louvered fin exchanger with a fin pitch to louver pitch ratio of 0.76 and a louver angle of 27{sup o}. The Reynolds numbers tested, based on louver pitch, were between 230 and 1016. A number of geometrical winglet parameters, including angle of attack, aspect ratio, direction, and shape, were all evaluated based on heat transfer augmentation, friction factor augmentation, and efficiency index (combination of both augmentations). In an attempt to optimize these winglet parameters, tube wall heat transfer augmentations as high as 39% were achieved with associated friction factor augmentations as high as 23%. (author)

  19. A simple and accurate numerical network flow model for bionic micro heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, M.; Klein, P. [Fraunhofer Institute (ITWM), Kaiserslautern (Germany)

    2011-05-15

    Heat exchangers are often associated with drawbacks like a large pressure drop or a non-uniform flow distribution. Recent research shows that bionic structures can provide possible improvements. We considered a set of such structures that were designed with M. Hermann's FracTherm {sup registered} algorithm. In order to optimize and compare them with conventional heat exchangers, we developed a numerical method to determine their performance. We simulated the flow in the heat exchanger applying a network model and coupled these results with a finite volume method to determine the heat distribution in the heat exchanger. (orig.)

  20. 基于曲线拟合优化设计肋片管换热器%Using Curve Fitting to Optimize of Fin and Tube Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    杨恒; 朱梅; 远高

    2013-01-01

      主要对等厚环肋传热过程进行数值分析,利用曲线拟合的方法计算不同肋片尺寸下的散热量和肋效率的精确解,并在金属消耗一定和散热量一定情况下,优化等厚环肋的结构。%  This thesis discusses numerical analysis the process of heat transfer by uniform annular fin, using the curve fitting method to calculate the exact solution of heat transfer and fin sufficiency under the different fin sizes, and optimize of the structure of the uniform annular fin based on the same metal consumption and the same heat transfer of a single fin.

  1. Modelling Heat Exchangers for Domestic Boilers

    Directory of Open Access Journals (Sweden)

    S. F. C. F. Teixeira

    2000-01-01

    Full Text Available In the present paper the thermal behaviour of fin-tube heat exchangers is modeled. Particular attention has been given to the plate fins. The heat fluxes in the fins are described using a finite volume technique to discretize the energy equation. The thermal interactions with the water in the tubes and the surrounding air are treated as external boundaries, using appropriate relationships for forced convection in pipes and flat plates. The numerical results are presented in terms of dimensionless numbers (Fourier, Biot and geometric ratios which are found to be representative for this particular geometry. Furthermore, the effect of thermal gradients along the fin surface upon the fin efficiency is investigated. Based on a differential model for the heat balances, design charts have been developed for the thermal analysis of heat exchangers.

  2. Carbon nanotube heat-exchange systems

    Science.gov (United States)

    Hendricks, Terry Joseph; Heben, Michael J.

    2008-11-11

    A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).

  3. Multidimensional numerical modeling of heat exchangers

    Science.gov (United States)

    Sha, W. T.; Yang, C. I.; Kao, T. T.; Cho, S. M.

    A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG).

  4. VENTILATION SYSTEM WITH GROUND HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Vyacheslav Pisarev

    2016-11-01

    Full Text Available Ventilation systems consume more and more energy because of the often complex treatment of the air supplied to closed spaces. Looking for sources of energy allow for significant savings costs, which often translate into renewable energy sources. One of the more popular solutions is to use energy from the ground by various methods. Known and relatively common solutions are based on ground heat exchanger and ground collector cooperating with a heat pump. The paper presents the possibility of cooperation ventilation system with ground air heat exchanger and heat pump both in summer and winter period. A number solutions of this type of system, supported by calculation examples and moist air transformation in the Moliere chart have been presented. Support ventilation system with renewable energy sources allows significant savings in operating as shown in the article.

  5. Optimal counter-current exchange networks

    CERN Document Server

    Farr, Robert S

    2016-01-01

    We construct a general analysis for exchange devices linking their efficiency to the (potentially fractal) geometry of the exchange surface and supply network. For certain parameter ranges, we show that the optimal exchanger consists of densely packed pipes which span a thin sheet of large area, which may be crumpled into a fractal surface and supplied with a fractal network of pipes. We present the efficiencies of such fractal exchangers, showing factor gains compared to regular exchangers, using parameters relevant for systems such as pigeon lungs and salmon gills.

  6. The optimum fin spacing of circular tube bank fin heat exchanger with vortex generators

    Science.gov (United States)

    Hu, Wanling; Su, Mei; Wang, Liangcheng; Zhang, Qiang; Chang, Limin; Liu, Song; Wang, Liangbi

    2013-09-01

    In real application, once the pattern of fin is determined, fin spacing of tube bank fin heat exchanger can be adjusted in a small region, and air flow velocity in the front of the heat exchanger is not all the same. Therefore, the effects of fin spacing on heat transfer performance of such heat exchanger are needed. This paper numerically studied the optimal fin spacing regarding the different front flow velocities of a circular tube bank fin heat exchanger with vortex generators. To screen the optimal fin spacing, an appropriate evaluation criterion JF was used. The results show that when front velocity is 1.75 m/s, the optimal fin spacing is 2.25 mm, when front velocity is 2.5 m/s, the optimal fin spacing is 2 mm, and when front velocity is higher than 2.5 m/s, the optimal fin spacing is 1.75 mm.

  7. The impact of heat exchanger fouling on the optimum operation and maintenance of the Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Kuosa, M.; Kaikko, J.; Koskelainen, L. [Lappeenranta University of Technology, Department of Energy and Environmental Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland)

    2007-07-15

    This paper focuses on the effect of heat exchanger fouling on the performance of the Stirling engine in combined heat and power (CHP) application. Fouling results from using biomass fuels and affects the heat exchanger that transfers heat into the engine. This heat exchanger is referred to as the heater. The heat exchanger that recovers heat from the flue gases is also affected by fouling. To determine the performance of the Stirling engine, a commercial Stirling analysis tool is applied together with models that have been developed for the heat transfer in the heater, regenerator and cooler of the engine. The Stirling engine model uses constant temperatures for the heat addition and rejection, with the theory of displacement engine as a basis. The fouling in the heat exchanger is taken into account by using a fouling factor that corresponds with the degradation in the total heat transfer coefficient. The Stirling engine model together with the model for heat exchanger fouling makes it possible to estimate the effect of fouling on the performance of the Stirling engine. A cost model is developed for the engine to translate changes in performance into economy in CHP operation. In the studied application, the Stirling engine is operated by the heat demand. Together with the selected control method, performance and cost models compose a tool for the simulation and optimization of the system. The use of the models to determine the optimal cleaning interval of the heat exchanger surfaces is considered. (author)

  8. Liquid Salt Heat Exchanger Technology for VHTR Based Applications

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark; Sridhara, Kumar; Allen, Todd; Peterson, Per

    2012-10-11

    The objective of this research is to evaluate performance of liquid salt fluids for use as a heat carrier for transferring high-temperature process heat from the very high-temperature reactor (VHTR) to chemical process plants. Currently, helium is being considered as the heat transfer fluid; however, the tube size requirements and the power associated with pumping helium may not be economical. Recent work on liquid salts has shown tremendous potential to transport high-temperature heat efficiently at low pressures over long distances. This project has two broad objectives: To investigate the compatibility of Incoloy 617 and coated and uncoated SiC ceramic composite with MgCl2-KCl molten salt to determine component lifetimes and aid in the design of heat exchangers and piping; and, To conduct the necessary research on the development of metallic and ceramic heat exchangers, which are needed for both the helium-to-salt side and salt-to-process side, with the goal of making these heat exchangers technologically viable. The research will consist of three separate tasks. The first task deals with material compatibility issues with liquid salt and the development of techniques for on-line measurement of corrosion products, which can be used to measure material loss in heat exchangers. Researchers will examine static corrosion of candidate materials in specific high-temperature heat transfer salt systems and develop an in situ electrochemical probe to measure metallic species concentrations dissolved in the liquid salt. The second task deals with the design of both the intermediate and process side heat exchanger systems. Researchers will optimize heat exchanger design and study issues related to corrosion, fabrication, and thermal stresses using commercial and in-house codes. The third task focuses integral testing of flowing liquid salts in a heat transfer/materials loop to determine potential issues of using the salts and to capture realistic behavior of the salts in a

  9. 14 CFR 29.1125 - Exhaust heat exchangers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust heat exchangers. 29.1125 Section 29... exchangers. For reciprocating engine powered rotorcraft the following apply: (a) Each exhaust heat exchanger... is subject to contact with exhaust gases; and (4) No exhaust heat exchanger or muff may have...

  10. 14 CFR 25.1125 - Exhaust heat exchangers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust heat exchangers. 25.1125 Section 25... exchangers. For reciprocating engine powered airplanes, the following apply: (a) Each exhaust heat exchanger... provisions wherever it is subject to contact with exhaust gases; and (4) No exhaust heat exchanger or...

  11. Exergy-Economic Criteria for Evaluating Heat Exchanger Performance

    Institute of Scientific and Technical Information of China (English)

    Wu Shuangying; Li Yourong

    2001-01-01

    Based on the exergy-economic analysis of heat exchanger heat transfer and flow process, two new exergyeconomic criteria which are defined as the total costs per unit heat transfer rate ηt t for heat transfer exchanger and the net profit per unit heat recovery rate ηr for heat recovery exchanger respectively are put forward.Furthermore, the application of criteria is illustrated by the evaluation of down-flow, counter-flow and cross-flow heat exchangers performance. The methods employed and results presented in this paper can serve as a guide for the performance evaluation of heat exchangers.

  12. Feedback linearisation of a heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, M.H.R.F.; Devanathan, R. Sr. [Nanyang Technological Univ. (Singapore)

    1994-12-31

    The main contribution of the paper is to provide an explicit necessary and sufficient conditions for the system to be locally linearisable in terms of parameters of the heat exchanger model. Examples illustrate how the controllability issues which are standard in linear system theory can be naturally extended to the nonlinear system model via the linearising transformation.

  13. Solidification studies of automotive heat exchanger materials

    Science.gov (United States)

    Carlberg, T.; Jaradeh, M.; Kamgou Kamaga, H.

    2006-11-01

    Modifications of the aluminum alloy AA 3003 have been studied to improve and tailorits properties for applications in automotive heat exchangers. Laboratory techniques have been applied to simulate industrial direct-chill casting, and some basic solidification studies have been conducted. The results are coupled to structures observed in industrial-size ingots and discussed in terms of structure-property relations.

  14. Weld manufacturing of big heat-exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Braeutigam, M.; Huppertz, P.H.

    1986-06-24

    The topic of this article are big heat exchangers, which are developed and constructed to minimize energy losses in plants of process engineering. Some welding specifications are discussed in detail. Some constructive details, as e.g. materials selection and vibration safety complete this contribution.

  15. Measurement of heat and moisture exchanger efficiency.

    Science.gov (United States)

    Chandler, M

    2013-09-01

    Deciding between a passive heat and moisture exchanger or active humidification depends upon the level of humidification that either will deliver. Published international standards dictate that active humidifiers should deliver a minimum humidity of 33 mg.l(-1); however, no such requirement exists, for heat and moisture exchangers. Anaesthetists instead have to rely on information provided by manufacturers, which may not allow comparison of different devices and their clinical effectiveness. I suggest that measurement of humidification efficiency, being the percentage moisture returned and determined by measuring the temperature of the respired gases, should be mandated, and report a modification of the standard method that will allow this to be easily measured. In this study, different types of heat and moisture exchangers for adults, children and patients with a tracheostomy were tested. Adult and paediatric models lost between 6.5 mg.l(-1) and 8.5 mg.l(-1) moisture (corresponding to an efficiency of around 80%); however, the models designed for patients with a tracheostomy lost between 16 mg.l(-1) and 18 mg.l(-1) (60% efficiency). I propose that all heat and moisture exchangers should be tested in this manner and percentage efficiency reported to allow an informed choice between different types and models.

  16. A STUDY ON THE FINS OF HEAT EXCHANGERS FROM OPTIMIZATION OF ENTROPY GENERATION%换热器肋片的最小熵产优化研究

    Institute of Scientific and Technical Information of China (English)

    苏亚欣; 骆仲泱; 岑可法

    1999-01-01

    The purpose of this paper is to find a new way of fin design to minimize the irreversibilities due to heat transfer and fluid friction and maximize the available work of the working fluid. The general entropy generation formulas for fins are derived at first according to the first and second law of thermodynamics, then a theoretical analysis on cylindrical pin fins and rectangular straight fins is made by using the above formulas. The minimum entropy generation formulas for these two types of fins are obtained and a principle for fin optimization is proposed, where the minimum entropy generation is chosen to be the objective function to be studied. The effect of different parameters on fin entropy generation is discussed in detail in forced convection heat transfer.

  17. Optimizing Sustainable Geothermal Heat Extraction

    Science.gov (United States)

    Patel, Iti; Bielicki, Jeffrey; Buscheck, Thomas

    2016-04-01

    Geothermal heat, though renewable, can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal. As such, the sustainability of a geothermal resource is typically viewed as preserving the energy of the reservoir by weighing heat extraction against renewability. But heat that is extracted from a geothermal reservoir is used to provide a service to society and an economic gain to the provider of that service. For heat extraction used for market commodities, sustainability entails balancing the rate at which the reservoir temperature renews with the rate at which heat is extracted and converted into economic profit. We present a model for managing geothermal resources that combines simulations of geothermal reservoir performance with natural resource economics in order to develop optimal heat mining strategies. Similar optimal control approaches have been developed for managing other renewable resources, like fisheries and forests. We used the Non-isothermal Unsaturated-saturated Flow and Transport (NUFT) model to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are integrated into the optimization model to determine the extraction path over time that maximizes the net present profit given the performance of the geothermal resource. Results suggest that the discount rate that is used to calculate the net present value of economic gain is a major determinant of the optimal extraction path, particularly for shallower and cooler reservoirs, where the regeneration of energy due to the natural geothermal heat flux is a smaller percentage of the amount of energy that is extracted from the reservoir.

  18. A novel method to improve the performance of heat exchanger--Temperature fields coordination of fluids

    Institute of Scientific and Technical Information of China (English)

    GUO Zengyuan; WEI Shu; CHENG Xinguang

    2004-01-01

    The methods to enhance the heat transfer in heat exchanger may be classified into two levels: one is to improve the heat transfer coefficient; the other is to upgrade the whole arrangement of the heat exchangers. For the second level, the performance of heat exchanger can be upgraded by increasing the coordination degree between the temperature fields of cold and hot fluids. When the temperature distributions are similar to each other, the temperature difference field (TDF) is more uniform, which means that the temperature fields are more coordinated with each other. For the cross-flow heat exchanger, rearrangement of the heat exchange surface area should improve the heat transfer effectiveness, which is even equal to that of the counter-flow heat exchanger when the surface area is reassigned optimally. For the multi-stream heat exchanger, the thermal performance is also dependent on the uniformity of the TDF, and the parallel-flow arrangement may achieve higher heat exchange effectiveness than the counter-flow arrangement, which indicates that the performance of heat exchanger depends on the coordination degree of temperature fields instead of the flow arrangement.

  19. Selection and costing of heat exchangers

    Science.gov (United States)

    1992-12-01

    ESDU 92013 gives guidance on the selection of heat exchanger types for a given duty against various criteria; they include the general characteristics, together with such detailed aspects as the ranges of pressure and temperature appropriate, compatibility with the fluids involved, space and weight requirements, and cleaning accessibility and maintenance. That allows an initial choice to be made from 18 principal types of exchangers. The various types are all illustrated. A final choice can then be made between the feasible types on the basis of costs. Detailed costing data provided by manufacturers are tabulated as a function of heat load, operating pressure and the types of cold- and hot-side fluids for the following types of exchangers: shell-and-tube, double-pipe, printed-circuit, plate-fin, air-cooled and welded plate. Costing data are also tabulated as a function of heat load and the types of cold- and hot-side fluids for gasketed-plate exchangers. Seven worked examples of selection based on technical suitability and using the tabulated cost data illustrate fully the use of the information.

  20. Investigation of effect of oblique ridges on heat transfer in plate heat exchangers

    Science.gov (United States)

    Novosád, Jan; Dvořák, Václav

    2014-03-01

    This article deals with numerical investigation of flow in plate heat exchangers. These are counterflow heat exchangers formed by plates. These plates are shaped by the ridges to intensify heat transfer. The objective of the work is the investigation of effect of straight oblique triangular ridges for increasing of heat transfer and pressure losses. The ridges on adjacent plates intersect and thus form a channel of complex shape. The research includes various types of ridges with different fillets and ridges spacing.The work also investigates the number of ridges that is necessary for optimization calculations. Obtained data are analysed and the heat transfer coefficient and pressure loss are evaluated. Conclusion describes the effect of fillets, ridges pitch and number of ridges.

  1. PENGARUH PENGGUNAAN BAFFLE PADA SHELL-AND-TUBE HEAT EXCHANGER

    OpenAIRE

    Ekadewi Anggraini Handoyo

    2001-01-01

    Shell-and-tube heat exchanger is a device commonly used to transfer heat. To enhance the heat transfer occurred and to support the tubes inside the shell, baffles are installed. Better heat transfer is obviously expected in a heat exchanger. A research is done to find out the effect of baffle used toward the effectiveness and pressure drop in heat exchanger. The result is that the effectiveness increases when the baffles are installed. Effectiveness increases as the spacing between the baffle...

  2. Heat Transfer of Nanofluid in a Double Pipe Heat Exchanger.

    Science.gov (United States)

    Aghayari, Reza; Maddah, Heydar; Zarei, Malihe; Dehghani, Mehdi; Kaskari Mahalle, Sahar Ghanbari

    2014-01-01

    This paper investigates the enhancement of heat transfer coefficient and Nusselt number of a nanofluid containing nanoparticles (γ-AL2O3) with a particle size of 20 nm and volume fraction of 0.1%-0.3% (V/V). Effects of temperature and concentration of nanoparticles on Nusselt number changes and heat transfer coefficient in a double pipe heat exchanger with counter turbulent flow are investigated. Comparison of experimental results with valid theoretical data based on semiempirical equations shows an acceptable agreement. Experimental results show a considerable increase in heat transfer coefficient and Nusselt number up to 19%-24%, respectively. Also, it has been observed that the heat transfer coefficient increases with the operating temperature and concentration of nanoparticles.

  3. RECITAL SCRUTINY ON TUBE-INTUBE COMPACT HEAT EXCHANGERS

    Directory of Open Access Journals (Sweden)

    V.NATARAJAN,

    2011-04-01

    Full Text Available This paper focused on the investigational cram of the recital characteristics of tube-in-tube compact heat exchangers. Experiments are conducted in the compact heat exchangers with R-134a and liquefiedpetroleum gas. The effectiveness of the heat exchangers was calculated using the experiment data and it was found that the effectiveness of heat exchanger-1 is above 75 and heat exchanger-2 is above 84% for R-134a.The effectiveness of heat exchanger-1 is about 60% and heat exchanger-2 is about 81% for liquefied petroleum gas. In this paper, details about the new tube-in-tube type compact heat exchanger, experimental setup, results and conclusions are discussed.

  4. evaluation of total annual costs of heat exchanger networks using ...

    African Journals Online (AJOL)

    user

    This study presents pinch analysis of some heat exchanger networks (HENs) problems using Hint integration .... of chemical process design for the conversion of raw materials to ... task is to synthesis a heat exchanger network that will.

  5. Heat Sink Design and Optimization

    Science.gov (United States)

    2015-12-01

    Natural convection Radiation Design Modeling Optimization 16. SECURITY CLASSIFICATION OF: 17...Hs = 3.94 in.  Width Ws = 5.42 in.  Fins  Height Hf = 0.98 in.  Length...different fin thicknesses (tf) The next parameter considered was fin height, Hf . Smaller height has a negative influence on overall heat sink

  6. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  7. Novel Power Electronics Three-Dimensional Heat Exchanger: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, K.; Cousineau, J.; Lustbader, J.; Narumanchi, S.

    2014-08-01

    Electric drive systems for vehicle propulsion enable technologies critical to meeting challenges for energy, environmental, and economic security. Enabling cost-effective electric drive systems requires reductions in inverter power semiconductor area. As critical components of the electric drive system are made smaller, heat removal becomes an increasing challenge. In this paper, we demonstrate an integrated approach to the design of thermal management systems for power semiconductors that matches the passive thermal resistance of the packaging with the active convective cooling performance of the heat exchanger. The heat exchanger concept builds on existing semiconductor thermal management improvements described in literature and patents, which include improved bonded interface materials, direct cooling of the semiconductor packages, and double-sided cooling. The key difference in the described concept is the achievement of high heat transfer performance with less aggressive cooling techniques by optimizing the passive and active heat transfer paths. An extruded aluminum design was selected because of its lower tooling cost, higher performance, and scalability in comparison to cast aluminum. Results demonstrated a heat flux improvement of a factor of two, and a package heat density improvement over 30%, which achieved the thermal performance targets.

  8. Laser Processed Condensing Heat Exchanger Technology Development

    Science.gov (United States)

    Hansen, Scott; Wright, Sarah; Wallace, Sarah; Hamilton, Tanner; Dennis, Alexander; Zuhlke, Craig; Roth, Nick; Sanders, John

    2017-01-01

    The reliance on non-permanent coatings in Condensing Heat Exchanger (CHX) designs is a significant technical issue to be solved before long-duration spaceflight can occur. Therefore, high reliability CHXs have been identified by the Evolvable Mars Campaign (EMC) as critical technologies needed to move beyond low earth orbit. The Laser Processed Condensing Heat Exchanger project aims to solve these problems through the use of femtosecond laser processed surfaces, which have unique wetting properties and potentially exhibit anti-microbial growth properties. These surfaces were investigated to identify if they would be suitable candidates for a replacement CHX surface. Among the areas researched in this project include microbial growth testing, siloxane flow testing in which laser processed surfaces were exposed to siloxanes in an air stream, and manufacturability.

  9. Performance Investigation of Plate Type Heat Exchanger (A Case Study

    Directory of Open Access Journals (Sweden)

    Simarpreet Singh

    2014-04-01

    Full Text Available Heat exchanger is a thermodynamic system which is most commonly used in the process industry for exchanging heat energy between the fluids. flowing in the same or opposite direction. It is desired that effectiveness of heat exchanger should remain as large as possible. Heat exchanger's performance may be improved by the addition of fins or corrugations. These investigations include design of plate type heat exchanger, heat transfer enhancement, flow phenomenon and cleanliness factor. In process plants, this type of heat exchange is generally used for recovering heat content of exhaust steam. However, with the flow of fluid for a long period, fouling occurs on the plate surface. Therefore, it is required to investigate the effect of fouling, wherever the heat exchanger is installed. An extensive experimental investigation has been carried out under clean and dirty condition of the said plate type heat exchanger. Heat transfer and flow data were collected in experiment. From collected data heat transfer rate, overall heat transfer coefficient, fouling factor and cleanliness factor were evaluated. Based upon the cleanliness factor data, next date of cleanliness for plate type heat exchanger was predicted. It is felt that the outcome of the present research work may be quite useful for efficient operation of plate type heat exchanger installed in Process plants.

  10. Analysis of the heat transfer in double and triple concentric tube heat exchangers

    Science.gov (United States)

    Rădulescu, S.; Negoiţă, L. I.; Onuţu, I.

    2016-08-01

    The tubular heat exchangers (shell and tube heat exchangers and concentric tube heat exchangers) represent an important category of equipment in the petroleum refineries and are used for heating, pre-heating, cooling, condensation and evaporation purposes. The paper presents results of analysis of the heat transfer to cool a petroleum product in two types of concentric tube heat exchangers: double and triple concentric tube heat exchangers. The cooling agent is water. The triple concentric tube heat exchanger is a modified constructive version of double concentric tube heat exchanger by adding an intermediate tube. This intermediate tube improves the heat transfer by increasing the heat area per unit length. The analysis of the heat transfer is made using experimental data obtained during the tests in a double and triple concentric tube heat exchanger. The flow rates of fluids, inlet and outlet temperatures of water and petroleum product are used in determining the performance of both heat exchangers. Principally, for both apparatus are calculated the overall heat transfer coefficients and the heat exchange surfaces. The presented results shows that triple concentric tube heat exchangers provide better heat transfer efficiencies compared to the double concentric tube heat exchangers.

  11. 14 CFR 23.1125 - Exhaust heat exchangers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust heat exchangers. 23.1125 Section 23... § 23.1125 Exhaust heat exchangers. For reciprocating engine powered airplanes the following apply: (a) Each exhaust heat exchanger must be constructed and installed to withstand the vibration, inertia,...

  12. 40 CFR 63.1435 - Heat exchanger provisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Heat exchanger provisions. 63.1435... Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63.1435 Heat exchanger... for heat exchange systems, with the exceptions noted in paragraphs (b) through (e) of this section....

  13. Selecting the form of plate corrugations of heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pavlenko, V.F.; Nagornyi, V.E.; Dolinskii, V.M.; Kolokolova, T.G.; Chekhov, O.S.

    1987-03-01

    The authors, in the interest of enhancing the thermal efficiency of plate-type heat exchangers, seek to optimize the pattern and size of the corrugations and surface area of these plates as well as their thickness by assessing the corrosion and scale protection afforded by thermoplastic coatings applied to the carbon steels used in the plates. They test the coatings for the effects of pressure, temperature, and various corrosive media, and demonstrate a parametric technique for optimizing pressure and temperature distribution over the corrugated area, for reducing the potential for deformation, and for prolonging plate durability.

  14. The Conduction of Heat through Cryogenic Regenerative Heat Exchangers

    Science.gov (United States)

    Superczynski, W. F.; Green, G. F.

    2006-04-01

    The need for improved regenerative cryocooler efficiency may require the replacement of conventional matrices with ducts. The ducts can not be continuous in the direction of temperature gradient when using conventional materials to prevent unacceptable conduction losses. However, this discontinuity creates a complex geometry to model and determine conduction losses. Chesapeake Cryogenics, Inc. has designed, fabricated and tested an apparatus for measuring the heat conduction through regenerative heat exchangers implementing different matrices. Data is presented for stainless steel photo etched disk, phophorus-bronze embossed ribbon coils and screens made of both stainless steel and phosphorus-bronze. The heat conduction was measured with the regenerators evacuated and pressurized with helium gas. In this test apparatus, helium gas presence increased the heat leak significantly. A description of the test apparatus, instrumentation, experimental methods and data analysis are presented.

  15. Optimal control of induction heating processes

    CERN Document Server

    Rapoport, Edgar

    2006-01-01

    This book introduces new approaches to solving optimal control problems in induction heating process applications. Optimal Control of Induction Heating Processes demonstrates how to apply and use new optimization techniques for different types of induction heating installations. Focusing on practical methods for solving real engineering optimization problems, the text features a variety of specific optimization examples for induction heater modes and designs, particularly those used in industrial applications. The book describes basic physical phenomena in induction heating and induction

  16. 紧凑式热交换器设计选型的多级模糊优选决策分析%Optimum Lectotype of Compact Heat Exchangers Based on Multi-level Fuzzy Optimization

    Institute of Scientific and Technical Information of China (English)

    吴恩; 周帼彦; 涂善东; 司海飞

    2013-01-01

    热交换器是过程机械的典型产品,是工艺过程中的关键设备之一,在现代工程中占有重要的地位.随着能源问题的日渐突显,节能降耗成为工业生产的重要目标,研制适用于不同工况要求的高效能换热设备已成为当前发展节能技术的关键,相应的设计方法和软件亟待开发.基于技术性能与经济性能综合考虑的思想,采用模糊优选理论中的模糊综合评价法和模糊物元分析法,针对紧凑式热交换器半结构性的特点,利用优选关系对比法进行了量化并建立了三级模糊优化选型,得到了较为理想的结果.%Heat exchangers are the typical products of the process equipment, which have been playing an important role in process engineering. With the increase of awareness of energy shortage, saving energy and reducing waste have become the major principle of industrial production. The key to develop the energy saving technology has been the design of the highly efficient heat exchangers adapted to the different working conditions. It is thus of urgent need to develop the related design methodology and software. Because of the difficulties met in conception design of compact heat exchangers, a multi-level, multi-factor and non-structural fuzzy optimum decision model is used in the optimal selection of compact heat exchangers. A three-level fuzzy optimum decision is introduced with success to cover most of the effective factors and determine the optimal design projects, which includes six design projects and eight influencing factors.

  17. Bypass Selection for Control of Heat Exchanger Network

    Institute of Scientific and Technical Information of China (English)

    SUN Lin; LUO Xionglin; HOU Benquan; BAI Yujie

    2013-01-01

    Considering the flexibility and controllability of heat exchanger networks (HENs),bypasses are widely used for effective control of process stream target temperatures.However,the optimal location for the bypass is generally difficult to design with the trade-off between controllability and capital investments.In this paper,based on the steady-state model of heat exchanger networks the optimal bypass location was firstly selected by iteratively calculating the non-square Relative Gain Array (ns-RGA).To simplify the calculation process,rules of bypass selection were also proposed.In order to evaluate this method,then,the structural controllability of heat exchanger networks was analyzed.With both the consideration of the controllability and capital investments,the bypasses locations were finally selected.A case study on the HEN in Crude Distillation Unit was presented in which the ns-RGA and structural controllability were used to select bypasses and also to evaluate the results.

  18. Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

    Science.gov (United States)

    Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

    2016-06-01

    Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

  19. Heat exchanger life extension via in-situ reconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David E.; Muralidharan, Govindarajan

    2016-06-28

    A method of in-situ reconditioning a heat exchanger includes the steps of: providing an in-service heat exchanger comprising a precipitate-strengthened alloy wherein at least one mechanical property of the heat exchanger is degraded by coarsening of the precipitate, the in-service heat exchanger containing a molten salt working heat exchange fluid; deactivating the heat exchanger from service in-situ; in a solution-annealing step, in-situ heating the heat exchanger and molten salt working heat exchange fluid contained therein to a temperature and for a time period sufficient to dissolve the coarsened precipitate; in a quenching step, flowing the molten salt working heat-exchange fluid through the heat exchanger in-situ to cool the alloy and retain a supersaturated solid solution while preventing formation of large precipitates; and in an aging step, further varying the temperature of the flowing molten salt working heat-exchange fluid to re-precipitate the dissolved precipitate.

  20. High pressure ratio cryocooler with integral expander and heat exchanger

    Science.gov (United States)

    Crunkleton, J. A.; Smith, J. L., Jr.; Iwasa, Y.

    A new 1 W, 4.2 K cryocooler is under development that is intended to miniaturize helium temperature refrigeration systems using a high-pressure-ratio Collins-type cycle. The configuration resulted from optimization studies of a saturated vapor compression (SCV) cycle that employs miniature parallel-plate heat exchangers. The basic configuration is a long displacer in a close-fitting, thin-walled cylinder. The displacer-to-cylinder gap is the high-pressure passage of the heat exchanger, and the low-pressure passage is formed by a thin tube over the OD of the cylinder. A solenoid-operated inlet valve admits 40 atm helium to the displacer-to-cylinder gap at room temperature, while the solenoid-operated exhaust valve operates at 4 atm. The single-stage cryocooler produces 1 W of refrigeration at 40 K without precooling and at 20 K with liquid nitrogen precooling.

  1. A Simple Tubesheet Layout Program for Heat Exchangers

    Directory of Open Access Journals (Sweden)

    S. Murali

    2008-01-01

    Full Text Available The development of tubesheet layout program for shell and tube heat exchangers is presented in this study. Program is written in AutoLISP language, which provides standard tubesheet layout drawing as per standard codes and non standard tubsheet in AutoCAD Environment. The program computes the optimal number of tube count and lays out drawing with respecting constraints, including the shell ID, number of passes, center to center distance of tubes and tube outer diameter. Tubesheet layout drawing can be used as template for actual tubesheet. Furthermore the program is validated with open literature and shown good agreement with it. Besides the tubesheet for Heat exchangers this method can be extended to the tube counts of sheave plates and perforated plates of distillation column and Cooling Towers.

  2. Characteristics of heat flow in recuperative heat exchangers

    Directory of Open Access Journals (Sweden)

    Lalović Milisav

    2005-01-01

    Full Text Available A simplified model of heat flow in cross-flow tube recuperative heat exchangers (recuperators was presented in this paper. One of the purposes of this investigation was to analyze changes in the values of some parameters of heat transfer in recuperators during combustion air preheating. The logarithmic mean temperature (Atm and overall heat transfer coefficient (U, are two basic parameters of heat flow, while the total heated area surface (A is assumed to be constant. The results, presented as graphs and in the form of mathematical expressions, were obtained by analytical methods and using experimental data. The conditions of gaseous fuel combustions were defined by the heat value of gaseous fuel Qd = 9263.894 J.m-3, excess air ratio λ= 1.10, content of oxygen in combustion air ν(O2 = 26%Vol, the preheating temperature of combustion air (cold fluid outlet temperature tco = 100-500°C, the inlet temperature of combustion products (hot fluid inlet temperature thi = 600-1100°C.

  3. 基于C++和智能图表合成最优换热网络的程序设计%Programming of intelligent graphs to synthesis optimized heat exchanger networks based on C++

    Institute of Scientific and Technical Information of China (English)

    李飞; 高维平; 杨莹; 何井松

    2012-01-01

    在合成最优换热网络时,存在着调优迭代计算时间长、过程复杂等问题,本文围绕这一课题,以智能图表法为理论基础,结合C++的编程思想,以Microsoft Visual Studio 2008为开发平台,利用换热网络优化节能技术编写了换热网络合成软件.该软件具有以下功能:根据冷、热物流相关数据,计算换热网络夹点、生成温—焓组合曲线图并标出夹点温度,计算出最大热回收量和最小能量体用量,根据物流匹配换热规则和智能图表对相关冷热物流进行匹配,计算出冷热物流热交换的热负荷、换热面积、操作费用等,自动合成最优换热网络并将计算结果存于文本文件result.txt中.经实例核算后与其它文献数据对比结果可靠合理,表明该程序应用方便,计算速度快,可大大简化合成换热网络的计算过程.%In heat exchanger networks long time computation and complex calculation were inevitable. In this paper, the intelligent graphs as the theoretical basis, and combined with the C++ programming ideas, software of synthesis of optimal heat exchanger networks was designed. Takes Microsoft Visual Studio 2008 as development platform. According to cold and hot streams related data, calculate the maximum thermal energy recovery and the minimum utility usage. And the software can draw composite curves and pinch point. At the same time, heat transfer areas and operating costs can be calculated, optimal heat exchanger networks is also synthesized basing on the rule of machine between cold and hot stream and intelligent graphs. The computed results are saved in text document result.txt. Indicated after the example calculation that this procedure application convenience, the computation speed is fast, the result is reliable. Simplifies the computational process of synthesis heat transfer network obviously.

  4. Microchannel Heat Exchangers with Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.; Ohadi, M.M.; Radermacher, R.

    2001-09-15

    The objective of the present study was to determine the performance of CO{sub 2} microchannel evaporators and gas coolers in operational conditions representing those of residential heat pumps. A set of breadboard prototype microchannel evaporators and gas coolers was developed and tested. The refrigerant in the heat exchangers followed a counter cross-flow path with respect to the airflow direction. The test conditions corresponded to the typical operating conditions of residential heat pumps. In addition, a second set of commercial microchannel evaporators and gas coolers was tested for a less comprehensive range of operating conditions. The test results were reduced and a comprehensive data analysis, including comparison with the previous studies in this field, was performed. Capacity and pressure drop of the evaporator and gas cooler for the range of parameters studied were analyzed and are documented in this report. A gas cooler performance prediction model based on non-dimensional parameters was also developed and results are discussed as well. In addition, in the present study, experiments were conducted to evaluate capacities and pressure drops for sub-critical CO{sub 2} flow boiling and transcritical CO{sub 2} gas cooling in microchannel heat exchangers. An extensive review of the literature failed to indicate any previous systematic study in this area, suggesting a lack of fundamental understanding of the phenomena and a lack of comprehensive data that would quantify the performance potential of CO{sub 2} microchannel heat exchangers for the application at hand. All experimental tests were successfully conducted with an energy balance within {+-}3%. The only exceptions to this were experiments at very low saturation temperatures (-23 C), where energy balances were as high as 10%. In the case of evaporators, it was found that a lower saturation temperature (especially when moisture condensation occurs) improves the overall heat transfer coefficient

  5. Technology Solutions Case Study: Foundation Heat Exchanger, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-03-01

    The foundation heat exchanger, developed by Oak Ridge National Laboratory, is a new concept for a cost-effective horizontal ground heat exchanger that can be connected to water-to-water or water-to-air heat pump systems for space conditioning as well as domestic water heating.

  6. Investigation Status of Heat Exchange while Boiling Hydrocarbon Fuel

    Directory of Open Access Journals (Sweden)

    D. S. Obukhov

    2006-01-01

    Full Text Available The paper contains analysis of heat exchange investigations while boiling hydrocarbon fuel. The obtained data are within the limits of the S.S. Kutateladze dependence proposed in 1939. Heat exchange at non-stationary heat release has not been investigated. The data for hydrocarbon fuel with respect to critical density of heat flow are not available even for stationary conditions.

  7. Analytical and experimental analysis of tube coil heat exchanger

    Science.gov (United States)

    Smusz, R.

    2016-09-01

    The paper presents the analytical and experimental analysis of heat transfer for the finned tube coil heat exchanger immersed in thermal storage tank. The tank is equipped with three helical-shaped heating coils and cylindrical- shaped stratification device. Two coils, upper and lower, use the water as a heating medium. The third, double wall heat exchanger coil, located at the bottom head on the tank is filled by the refrigerant (freon). Calculations of thermal power of water coil were made. Correlations of heat transfer coefficients in curved tubes were applied. In order to verify the analytical calculations the experimental studies of heat transfer characteristic for coil heat exchanger were performed.

  8. Development of Submersible Corrugated Pipe Sewage Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    BAI Li; SHI Yan; TAN Yu-fei

    2009-01-01

    Based on the characteristics of heat transfer for corrugated pipe,a method of calculating and de-sign on the submersible corrugated pipe sewage heat exchanger was put forward theoretically and experimental-ly.The actual movement parameters of air-conditioning system used in this heat exchanger were measured.The experimental result shows that the quantity of heat transfer of the corrugated pipe sewage heat exchanger can satisfy the building's load with the average coefficient of performance 4.55.At the same time.the quantity ot heat transfer of the corrugated pipe sewage heat exchanger was compared with that of the other nonmetallic sewage heat exchangers(i.e.,the plastic-Al pipe sewage heat exchanger and PP-R pipe sewage heat exchanger)experimentally.It is found out that the effect of heat transfer for submersible corrugated pipe sewage heat ex-changer is superior to those of the plastic-Al pipe and the PP-R pipe.The quantity of heat transfer per mile of corrugated pipe sewage heat exchanger is 5.2 times as much as that of the plastic-Al pipe,and it is 8.1 times as much as that of PP-R pipe.

  9. Topology Optimization of Thermal Heat Sinks

    DEFF Research Database (Denmark)

    Klaas Haertel, Jan Hendrik; Engelbrecht, Kurt; Lazarov, Boyan Stefanov

    2015-01-01

    In this paper, topology optimization is applied to optimize the cooling performance of thermal heat sinks. The coupled two-dimensional thermofluid model of a heat sink cooled with forced convection and a density-based topology optimization including density filtering and projection are implemented...... in COMSOL Multiphysics. The optimization objective is to minimize the heat sink’s temperature for a prescribed pressure drop and fixed heat generation. To conduct the optimization, COMSOL’s Optimization Module with GCMMA as the optimization method is used. The implementation of this topology optimization...

  10. Reliability analysis on a shell and tube heat exchanger

    Science.gov (United States)

    Lingeswara, S.; Omar, R.; Mohd Ghazi, T. I.

    2016-06-01

    A shell and tube heat exchanger reliability was done in this study using past history data from a carbon black manufacturing plant. The heat exchanger reliability study is vital in all related industries as inappropriate maintenance and operation of the heat exchanger will lead to major Process Safety Events (PSE) and loss of production. The overall heat exchanger coefficient/effectiveness (Uo) and Mean Time between Failures (MTBF) were analyzed and calculated. The Aspen and down time data was taken from a typical carbon black shell and tube heat exchanger manufacturing plant. As a result of the Uo calculated and analyzed, it was observed that the Uo declined over a period caused by severe fouling and heat exchanger limitation. This limitation also requires further burn out period which leads to loss of production. The MTBF calculated is 649.35 hours which is very low compared to the standard 6000 hours for the good operation of shell and tube heat exchanger. The guidelines on heat exchanger repair, preventive and predictive maintenance was identified and highlighted for better heat exchanger inspection and repair in the future. The fouling of heat exchanger and the production loss will be continuous if proper heat exchanger operation and repair using standard operating procedure is not followed.

  11. Expanded microchannel heat exchanger: design, fabrication and preliminary experimental test

    CERN Document Server

    Denkenberger, David C; Pearce, Joshua M; Zhai, John; 10.1177/0957650912442781

    2012-01-01

    This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The paper discusses one possible joining method - a new type of laser welding named "forward conduction welding," used to fabricate the prototype. The expanded heat exchanger has the potential to have counter-flow, cross-flow, or parallel-flow configurations, be used for all types of fluids, and be made of polymers, metals, or polymer-ceramic precursors. The cost and ineffectiveness reduction may be an order of magnitude or more, saving a large fraction of primary energy. The measured effectiveness of the prototype with 28 micro...

  12. Testing and analysis of load-side immersed heat exchangers for solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Farrington, R.B.; Bingham, C.E.

    1987-10-01

    This report describes work to determine the performance of load-side heat exchangers for use in residential solar domestic hot water systems. We measured the performance of four heat exchangers: a smooth coil and a finned coil having heat transfer areas of 2.5 m/sup 2/ (26 ft/sup 2/) and those having areas of 1.7 m/sup 2/ (19 ft/sup 2/). A numerical model using the thermal network program MITAS was constructed, and results were compared to the experimental results. Research showed a smooth coil with only 70% of the surface area of a finned coil performed better than the finned coil. Also, load-side heat exchangers can maintain and enhance stratification in storage tanks, permitting the use of control strategies that take advantage of stratified storage tanks to increase system performance. The analytical model, which agreed reasonably well with the experimental results, was used to vary heat exchanger flow rate and area and initial tank temperature for both a smooth- and a finned-coil heat exchanger. Increasing the heat exchanger flow rate and area results in higher heat transfer rates but not necessarily optimal performance. Lower initial tank temperatures resulted in reduced tank stratification. The smooth heat exchanger outperformed the finned heat exchanger with the same outside surface area. 15 refs., 37 figs., 9 tabs.

  13. Competition between stock exchanges and optimal trading

    NARCIS (Netherlands)

    van Kervel, V.L.

    2013-01-01

    This doctoral thesis focuses on two topics on trading in financial markets: competition between stock exchanges and optimal trading strategies. Chapter one analyzes the effect on the liquidity of a stock when it is traded on multiple trading venues, and distinguishes between competition from transpa

  14. Oxidizer heat exchangers for rocket engine operation in idle modes

    Science.gov (United States)

    Kanic, P. G.; Kmiec, T. D.

    1987-01-01

    The heat exchanger concept is discussed together with its role in rocket engine operation in idle modes. Two heat exchanger designs (low and high heat transfer) utilizing different approaches to achieve stable oxygen vaporization are presented as well as their performance test results. It is concluded that compact and lightweight heat exchangers can be used in a stable manner under the 'idle' operating conditions expected with the RL10 rocket engine.

  15. Complex Heat Exchangers for Improved Performance

    Science.gov (United States)

    Bran, Gabriela Alejandra

    After a detailed literature review, it was determined that there was a need for a more comprehensive study on the transient behavior of heat exchangers. Computational power was not readily available when most of the work on transient heat exchangers was done (1956 - 1986), so most of these solutions have restrictions, or very specific assumptions. More recently, authors have obtained numerical solutions for more general problems (2003 - 2013), but they have investigated very specific conditions, and cases. For a more complex heat exchanger (i.e. with heat generation), the transient solutions from literature are no longer valid. There was a need to develop a numerical model that relaxes the restrictions of current solutions to explore conditions that have not been explored. A one dimensional transient heat exchanger model was developed. There are no restrictions on the fluids and wall conditions. The model is able to obtain a numerical solution for a wide range of fluid properties and mass flow rates. Another innovative characteristic of the numerical model is that the boundary and initial conditions are not limited to constant values. The boundary conditions can be a function of time (i.e. sinusoidal signal), and the initial conditions can be a function of position. Four different cases were explored in this work. In the first case, the start-up of a system was investigated where the whole system is assumed to be at the same temperature. In the second case, the new steady state in case one gets disrupted by a smaller inlet temperature step change. In the third case, the new steady state in case one gets disrupted by a step change in one of the mass flow rates. The response of these three cases show that there are different transient behaviors, and they depend on the conditions imposed on the system. The fourth case is a system that has a sinusoidal time varying inlet temperature for one of the flows. The results show that the sinusoidal behavior at the inlet

  16. Numerical Simulation of Heat Transfer Characteristics of Horizontal Ground Heat Exchanger in Frozen Soil Layer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numerical results show that the frozen depth mainly depends on the soil's moisture content and ambient temperature. The heat transfer loss of horizontal GHE tends to grow with the increase of the soil's moisture content and the decrease of ambient temperature. Backfilled materials with optimal thermal conductivity can reduce the thermal loss effectively in the frozen soil. The applicability of the Chinese national standard "Technical Code for Ground Source Heat Pump (GB 50366-2005)" is verified. For a ground source heat pump project, the feasible layout of horizontal GHE should be determined based on the integration of the soil's structure, backfilled materials,weather data, and economic analysis.

  17. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    M. Thirumarimurugan

    2008-01-01

    Full Text Available Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in smaller plot areas and, in many cases, less initial investment. One such type ofcompact heat exchanger is the Plate-fin heat exchanger. The complexity of compact heat exchangerdesign equations results from the exchangers unique ability to transfer heat between multiple processstreams and a wide array of possible flow configurations. This paper presents the performanceevaluation of cross flow plate fin heat exchanger with several different Gas-Liquid systems.Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculatedfor the flow systems of Cross flow Heat Exchangers. A steady state model for the outlet temperature ofboth the cold and hot fluid and overall heat transfer coefficient of a plate-fin cross flow heat exchangerwas developed and simulated using MATLAB, which was verified with the experiments conducted.

  18. NUMERICAL STUDY ON FLOW DISTRIBUTION IN PLATE-FIN HEAT EXCHANGERS

    Institute of Scientific and Technical Information of China (English)

    张哲; 厉彦忠

    2003-01-01

    Objective To investigate the flow distribution in plate-fin heat exchangers and optimize the design of header configuration for plate-fin heat exchangers. Methods A mathematical model of header was proposed. The effects of the header configuration on the flow distribution in plate-fin heat exchangers were investigated by CFD. The second header configuration with a two-stage-distributing structure was brought forward to improve the performance of flow distribution. Results It is found that the flow maldistribution is very serious in the direction of header length for the conventional header used in industry. The numerical predictions indicate that the improved header configurations can effectively improve the performance of flow distribution in plate-fin heat exchangers. Conclusion The numerical simulation confirms that CFD should be a suitable tool for predicting the flow distribution. The method has a wide variety of applications in the design of plate-fin heat exchangers.

  19. Shell-and-double concentric-tube heat exchangers

    Science.gov (United States)

    Bougriou, Chérif; Baadache, Khireddine

    2010-03-01

    This study concerns a new type of heat exchangers, which is that of shell-and-double concentric-tube heat exchangers. These heat exchangers can be used in many specific applications such as air conditioning, waste heat recovery, chemical processing, pharmaceutical industries, power production, transport, distillation, food processing, cryogenics, etc. The case studies include both design calculations and performance calculations. It is demonstrated that the relative diameter sizes of the two tubes with respect to each other are the most important parameters that influence the heat exchanger size.

  20. Research on ground heat exchanger of Ground Source Heat Pump technique

    Institute of Scientific and Technical Information of China (English)

    LIU Dong-sheng; SUN You-hong; GAO Ke; WU Xiao-hang

    2004-01-01

    Ground Source Heat Pump technique and its operating principle are described in this paper. Ground heat exchanger is the key technique of ground source heat pump and its pattems are discussed. Software is helpful to design ground heat exchanger. A project of Chinese Ground Source Heat Pump is introduced and its market is more and more extensive.

  1. Experimental investigation of heat transfer and effectiveness in corrugated plate heat exchangers having different chevron angles

    Science.gov (United States)

    Kılıç, Bayram; İpek, Osman

    2017-02-01

    In this study, heat transfer rate and effectiveness of corrugated plate heat exchangers having different chevron angles were investigated experimentally. Chevron angles of plate heat exchangers are β = 30° and β = 60°. For this purpose, experimentally heating system used plate heat exchanger was designed and constructed. Thermodynamic analysis of corrugated plate heat exchangers having different chevron angles were carried out. The heat transfer rate and effectiveness values are calculated. The experimental results are shown that heat transfer rate and effectiveness values for β = 60° is higher than that of the other. Obtained experimental results were graphically presented.

  2. A Project to Design and Build Compact Heat Exchangers

    Science.gov (United States)

    Davis, Richard A.

    2005-01-01

    Students designed and manufactured compact, shell-and-tube heat exchangers in a project-based learning exercise integrated with our heat transfer course. The heat exchangers were constructed from common building materials available at home improvement centers. The cost of materials for a device was less than $20. The project gave students…

  3. Design and Numerical Parametric Study of Fractal Heat Exchanger

    OpenAIRE

    Huang, Zhiwei; Ling, Jiazhen; Hwang, Yunho; Aute, Vikrant; Radermacher, Reinhard

    2016-01-01

    Air-to-refrigerant heat exchangers are a main component in air-conditioning and heat pump systems and are therefore a topic of major research focus. Such heat exchangers, mainly made of fin-and-tube and microchannels, use fins to augment the heat transfer area of the air-side. Recently it has been shown that finless designs using ≤ 1 mm hydraulic diameter bare tubes can deliver better air-side heat transfer performance than conventional heat exchangers. In current study, a novel air-to-refr...

  4. Magnetic Heat Transfer Enhancements on Fin-Tube Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    Yan SU; C.T. HSU

    2007-01-01

    通过DNS方法解耦合的三维非稳态流动和固流体能量方程组,本文研究了两平行磁质平板和圆管所组成的肋片式圆管换热器单元与震荡流体间的传热过程.对不同的磁场频率和振幅的三维动态流热场的模拟结果表明增强磁场频率和振幅能很有效地增加周期平均传热强度达到强化传热的目的.%Two narrowly-gapped magnetic parallel plates embedding a circular disk was considered as a unit-cell to represent the fin-tube heat exchanger where heat from a circular tube was dissipated by a series of parallel equally-spaced thin plates in normal to the tube. The unsteady 3-D continuity,Navier-Stokes and energy equations for fluids and solids describing the convective heat transfer for the unit-cell geometry were solved numerically with DNS method. The present study aims on using oscillating flows and magnetic fields to enhance the heat transfer for various amplitudes and frequencies of the magnetic field. Results from cycle-averaged heat fluxes from the cylinder wall show that the increase in magnetic amplitude and frequency will greatly enhance the heat transfer. The effects of the oscillating magnetic field were discussed and the three dimensional flow and temperature fields were also presented.

  5. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    Energy Technology Data Exchange (ETDEWEB)

    Koplow, Jeffrey P.

    2016-02-16

    Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

  6. Performance of multiple mini-tube heat exchangers as an internal heat exchanger of a vapor-injection cycle heat pump

    Science.gov (United States)

    Jang, Jin Yong; Jeong, Ji Hwan

    2016-04-01

    A multiple mini-tube (MMT) heat exchanger was considered as an internal heat exchanger of vapor-injection cycle heat pump. Heat transfer and pressure drop in multiple mini-tube heat exchangers were numerically and experimentally investigated. Results show that the best performance of the MMT heat exchanger can be obtained when the intermediate-pressure two-phase refrigerant is supplied to the shell-side and this refrigerant reaches a saturated vapor state at the exit of the heat exchanger.

  7. Two-phase Flow Distribution in Heat Exchanger Manifolds

    OpenAIRE

    Vist, Sivert

    2004-01-01

    The current study has investigated two-phase refrigerant flow distribution in heat exchange manifolds. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass flow rate and gas and liquid distribution in the manifolds of compact heat exchangers. Twelve different manifold designs were used in the experiments, and CO2 and HFC-134a were used as refrigerants.

  8. Direct contact droplet heat exchangers for thermal management in space

    Science.gov (United States)

    Bruckner, A. P.; Hertzberg, A.

    1982-01-01

    A liquid droplet heat exchanger for space applications is described which transfers heat between a gas and a liquid metal dispersed into droplets. The ability of the droplet heat exchanger to transfer heat between two media in direct contact over a wide temperature range circumvents many of the material limitations of conventional tube-type heat exchangers and does away with complicated plumbing systems and their tendency toward single point failure. Droplet heat exchangers offer large surface to volume ratios in a compact geometry, very low gas pressure drop, and high effectiveness. The application of the droplet heat exchanger in a high temperature Brayton cycle is discussed to illustrate its performance and operational characteristics.

  9. OTEC heat exchanger design and producibility study. Part C. Appendixes G thru J. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-10-28

    Study results of a preliminary design and manufacturing study of 25-MW/sub e/ aluminium-tubed and titanium-tubed heat exchangers and 5-MW/sub e/ subscale heat exchangers for ocean thermal energy conversion are reported. Subcontractor engineering efforts are described including computer printout sheets from the optimization program; structural analysis of the pressure vessels, heat exchanger tubing, shell to tubesheet transition ring, vapor ports, and concrete pressure vessels; magnaforming of tube-to-tubesheets in aluminium; and explosion bonding and propellant swagging of tubes to tubesheets. (WHK)

  10. Optimized ground coupled heat pump design: Phase 1, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W.; Catan, M.; Le Doux, P.; Metz, P.D.; Saunders, J.H.

    1985-10-01

    This report describes the first phase of a project to design a water-to-air heat pump optimized for ground coupling applications. The project is being conducted jointly by Brookhaven National Laboratory (BNL), Oak Ridge National Laboratory (ORNL), and an industrial partner to be selected via a competitive procurement. In the completion of Phase I, three major tasks were completed. First, based on experimental work performed at BNL, water-refrigerant heat exchanger models were developed for incorporation into the ORNL heat pump optimization program. Next, a procedure was developed to generate correlations between heat pump entering fluid temperature and load. The correlations, called ''Source Temperature/Load Maps'', will tell the optimization program how many hours/season the heat pump will operate with any pair of values for these quantities. This report discusses these first two tasks within Phase I.

  11. Liquid-Liquid Heat Exchanger With Zero Interpath Leakage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future manned spacecraft will require thermal management systems that effectively and safely control the temperature in inhabited modules. Interface heat exchangers...

  12. The optimization model of the heat conduction structure

    Institute of Scientific and Technical Information of China (English)

    Yongcun Zhang; Shutian Liu

    2008-01-01

    An optimization model considering a novel thermal performance index to be the objective function is proposed for minimizing the highest temperature in this paper. Firstly, the performance of the conventional heat conduction optimization model, with the dissipation of heat transport potential capacity as the objective function, is evaluated by a one-dimensional heat conduction problem in a planar plate exchanger. Then, a new thermal performance index, named the geometric average temperature, is introduced. The new heat conduction optimization model, with the geometric average temperature as the objective function, is developed and the corresponding finite element formula is presented. The results show that the geometric average temperature is an ideal thermal performance index and the solution of the new model is close to the theoretical optimal solution.

  13. Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

    2014-01-01

    A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

  14. Sensitivity Analysis for DHRS Heat Exchanger Performance Tests of PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jonggan; Eoh, Jaehyuk; Kim, Dehee; Lee, Taeho; Jeong, Jiyoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The STELLA-1 facility has been constructed and separate effect tests of heat exchangers for DHRS are going to be conducted. Two kinds of heat exchangers including DHX (shell-and-tube sodium-to-sodium heat exchanger) and AHX (helical-tube sodium-to-air heat exchanger) will be tested for design codes V and V. Main test points are a design point and a plant normal operation point of each heat exchanger. Additionally, some plant transient conditions are taken into account for establishing a test condition set. To choose the plant transient test conditions, a sensitivity analysis has been conducted using the design codes for each heat exchanger. The sensitivity of the PGSFR DHRS heat exchanger tests (the DHX and AHX in the STELLA-1 facility) has been analyzed through a parametric study using the design codes SHXSA and AHXSA at the design point and the plant normal operation point. The DHX heat transfer performance was sensitive to the change in the inlet temperature of the shell-side and the AHX heat transfer performance was sensitive to the change in the inlet temperature of the tube side. The results of this work will contribute to an improvement of the test matrix for the separate effect test of each heat exchanger.

  15. Thermal Propulsion Capture System Heat Exchanger Design

    Science.gov (United States)

    Richard, Evan M.

    2016-01-01

    One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.

  16. A SIMPLIFIED PREDICTIVE CONTROL FOR A SHELL AND TUBE HEAT EXCHANGER

    OpenAIRE

    S.RAJASEKARAN,; Dr.T.KANNADASAN

    2010-01-01

    In this paper a simplified predictive control design is applied for the controlling a temperature of a fluid stream using the shell and tube heat exchanger. The predictive control design based on Dynamic Matrix Control (DMC) involves the complicated inversion computation for higher dimensional matrix. Using DMC for controlling a temperature of the shell and tube heat exchanger, there is still a need for optimization of conversation of energy. The simplified predictive control is based on DMC,...

  17. Online performance assessment of heat exchanger using artificial neural networks

    Directory of Open Access Journals (Sweden)

    C. Ahilan, S. Kumanan, N. Sivakumaran

    2011-09-01

    Full Text Available Heat exchanger is a device in which heat is transferred from one medium to another across a solid surface. The performance of heat exchanger deteriorates with time due to fouling on the heat transfer surface. It is necessary to assess periodically the heat exchanger performance, in order to maintain at high efficiency level. Industries follow adopted practices to monitor but it is limited to some degree. Online monitoring has an advantage to understand and improve the heat exchanger performance. In this paper, online performance monitoring system for shell and tube heat exchanger is developed using artificial neural networks (ANNs. Experiments are conducted based on full factorial design of experiments to develop a model using the parameters such as temperatures and flow rates. ANN model for overall heat transfer coefficient of a design/ clean heat exchanger system is developed using a feed forward back propagation neural network and trained. The developed model is validated and tested by comparing the results with the experimental results. This model is used to assess the performance of heat exchanger with the real/fouled system. The performance degradation is expressed using fouling factor (FF, which is derived from the overall heat transfer coefficient of design system and real system. It supports the system to improve the performance by asset utilization, energy efficient and cost reduction interms of production loss.

  18. Finite time exergoeconomic performance optimization for an irreversible universal steady flow variable-temperature heat reservoir heat pump cycle model

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2010-11-01

    Full Text Available An irreversible universal steady flow heat pump cycle model with variable-temperature heat reservoirs and the losses of heat-resistance and internal irreversibility is established by using the theory of finite time thermodynamics. The universal heat pump cycle model consists of two heat-absorbing branches, two heat-releasing branches and two adiabatic branches. Expressions of heating load, coefficient of performance (COP and profit rate of the universal heat pump cycle model are derived, respectively. By means of numerical calculations, heat conductance distributions between hot- and cold-side heat exchangers are optimized by taking the maximum profit rate as objective. There exist an optimal heat conductance distribution and an optimal thermal capacity rate matching between the working fluid and heat reservoirs which lead to a double maximum profit rate. The effects of internal irreversibility, total heat exchanger inventory, thermal capacity rate of the working fluid and heat capacity ratio of the heat reservoirs on the optimal finite time exergoeconomic performance of the cycle are discussed in detail. The results obtained herein include the optimal finite time exergoeconomic performances of endoreversible and irreversible, constant- and variable-temperature heat reservoir Brayton, Otto, Diesel, Atkinson, Dual, Miller and Carnot heat pump cycles.

  19. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    OpenAIRE

    Thirumarimurugan, M.; Kannadasan, T.; E. Ramasamy

    2008-01-01

    Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in...

  20. 基于全周期节能的有旁路换热网络裕量优化设计%Margin optimal design of heat exchanger network with bypasses based on life cycle energy saving

    Institute of Scientific and Technical Information of China (English)

    夏车奎; 罗雄麟; 孙琳

    2012-01-01

    换热网络全周期运行期间,由于设备老化等因素,换热性能逐步下降,能耗逐步提高.而当前工业换热网络的裕量设计并没有有效地解决此问题.因此提出了一种基于有旁路换热网络全周期节能优化的裕量优化设计方法,通过旁路调节,逐步释放有效面积裕量,达到全周期节能的目的.该优化方法以换热网络运行全周期内总累积费用为目标函数,同时考虑结垢热阻对换热器换热效果的影响以及旁路对换热网络的调节作用,在满足工艺条件的基础上求解换热网络的最优裕量,最终实现换热网络的持续节能.最后,以某炼油厂的常减压脱盐前换热网络为具体的研究对象,说明所提方法的有效性和使用前景.%For the life cycle of the heat exchanger network (HEN), the heat exchanger performance steps down and energy consumption steps up because of network equipment aging and other factors. And this problem is not resolved effectively by the present margin design for the HEN. A margin optimal design method of the HEN with bypasses based on life cycle energy saving was presented. Through bypass adjustment, effective margin area was released gradually, achieving the purpose of saving energy in the life cycle. The HEN life cycle operation accumulative total cost was considered as the objective function, and at the same time the effect of fouling of heat exchangers and bypass adjustment was included to solve the best margin while satisfying the operation conditions. Lastly sustaining energy conservation was realized. The HEN of a given crude distillation unit in a refinery was treated as the specific research object, illustrating the effectiveness and application prospect of the presented method.

  1. Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

    Science.gov (United States)

    Huang, Shouyuan; Xu, Xianfan

    2016-10-01

    This paper presents a methodology for design optimization of thermoelectric-based waste heat recovery systems called thermoelectric generators (TEGs). The aim is to maximize the power output from thermoelectrics which are used as add-on modules to an existing gas-phase heat exchanger, without negative impacts, e.g., maintaining a minimum heat dissipation rate from the hot side. A numerical model is proposed for TEG coupled heat transfer and electrical power output. This finite-volume-based model simulates different types of heat exchangers, i.e., counter-flow and cross-flow, for TEGs. Multiple-filled skutterudites and bismuth-telluride-based thermoelectric modules (TEMs) are applied, respectively, in higher and lower temperature regions. The response surface methodology is implemented to determine the optimized TEG size along and across the flow direction and the height of thermoelectric couple legs, and to analyze their covariance and relative sensitivity. A genetic algorithm is employed to verify the globality of the optimum. The presented method will be generally useful for optimizing heat-exchanger-based TEG performance.

  2. Fouling corrosion in aluminum heat exchangers

    Directory of Open Access Journals (Sweden)

    Su Jingxin

    2015-06-01

    Full Text Available Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS, and scanning electron microscope (SEM observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday’s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

  3. Evaluation of a Passive Heat Exchanger Based Cooling System for Fuel Cell Applications

    Science.gov (United States)

    Colozza, Anthony J.; Burke, Kenneth A.

    2011-01-01

    Fuel cell cooling is conventionally performed with an actively controlled, dedicated coolant loop that exchanges heat with a separate external cooling loop. To simplify this system the concept of directly cooling a fuel cell utilizing a coolant loop with a regenerative heat exchanger to preheat the coolant entering the fuel cell with the coolant exiting the fuel cell was analyzed. The preheating is necessary to minimize the temperature difference across the fuel cell stack. This type of coolant system would minimize the controls needed on the coolant loop and provide a mostly passive means of cooling the fuel cell. The results indicate that an operating temperature of near or greater than 70 C is achievable with a heat exchanger effectiveness of around 90 percent. Of the heat exchanger types evaluated with the same type of fluid on the hot and cold side, a counter flow type heat exchanger would be required which has the possibility of achieving the required effectiveness. The number of heat transfer units required by the heat exchanger would be around 9 or greater. Although the analysis indicates the concept is feasible, the heat exchanger design would need to be developed and optimized for a specific fuel cell operation in order to achieve the high effectiveness value required.

  4. A new method for analyzing heat exchangers-matching of temperature field

    Science.gov (United States)

    Wang, HuanGuang; Huai, XiuLan

    2012-10-01

    In heat exchangers, the magnitude of Nu of each duct is influenced by the temperature field, since the ratio of heat capacity rate will influence the matching status of the temperature field between contacting ducts, the total heat transfer coefficient is related with the ratio of heat capacity rate. Considering this relationship, a new method for analyzing heat exchanger is proposed — matching of temperature field. First, for a single duct with the temperature field varying exponentially along the flow direction, its Nu is calculated. Then under the hypothesis that the thermal resistance of the wall is negligible, the matching condition was set like this: both the temperature and heat flux are equal for the hot and cold fluids at the wall, so the matching relationship of parameter that describes the temperature field of the hot and cold fluids, was obtained. Finally the relationship between the total Nu and the ratio of heat capacity rate along with the ratio of inherent thermal resistance is obtained. Compared with traditional analyzing methods, the temperature matching method can be used to get the total heat transfer coefficient directly, and also be used for optimization of heat exchanger design. For a parallel flow, the optimal ratio of heat capacity rate is reciprocal to the ratio of inherent thermal resistance, and for a counter flow, the optimal ratio of heat capacity rate is zero or infinity.

  5. Experimental study on the effects of the number of heat exchanger modules on thermal characteristics in a premixed combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Byeonghun; Lee, Chang-Eon [Inha University, Incheon (Korea, Republic of); Kum, Sung Min [Halla University, Wonju (Korea, Republic of); Lee, Seungro [Chonbuk National University, Jeonju (Korea, Republic of)

    2016-01-15

    The effects of the number of heat exchanger modules on thermal characteristics were experimentally studied in a premixed combustion system with a cross-flow staggered-tube heat exchanger. The various heat exchanger modules, from 4 to 8, combined with a premixed burner were tested to investigate the performance of the heat exchanger through the surface area of the heat exchanger at various equivalence ratios. Additionally, the performance of the heat exchanger was analyzed by applying entropy generation theory to the heat exchanger system. As a result, although the heat transfer rate increases with the increase of the equivalence ratio, the NOx and CO concentrations also increase due to the increasing flame temperature. In addition, the entropy generation increases with an increase of the equivalence ratio. Furthermore, the heat transfer rate and the effectiveness are increased with the increase of the number of the heat exchanger modules. Also, the effectiveness is sharply increased when the number of the heat exchanger modules is increased from 4 to 5. Consequently, the optimal operating conditions regarding pollutant emission, effectiveness and entropy generation in this experimental range are 0.85 for the equivalence ratio and 8 for the number of heat exchanger modules.

  6. Continued Water-Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Hansen, Scott W.; Sheth, Rubik B.; Poynot, Joe; Giglio, Tony; Ungar, Gene K.

    2015-01-01

    In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to meet the full heat rejection demands. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HX's do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full-scale, Orion sized water-based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research on freeze front propagation to a full-scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Two units, Units A and B, were constructed and differed only in their midplate design. Both units failed multiple times during testing. This report highlights learning outcomes from these tests and are applied to a final sub-scale PCM HX which is slated to be tested on the ISS in early 2017.

  7. Combined Steady-State and Dynamic Heat Exchanger Experiment

    Science.gov (United States)

    Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

    2009-01-01

    This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

  8. A Liquid-Liquid Thermoelectric Heat Exchanger as a Heat Pump for Testing Phase Change Material Heat Exchangers

    Science.gov (United States)

    Sheth, Rubik B.; Makinen, Janice; Le, Hung V.

    2016-01-01

    The primary objective of the Phase Change HX payload on the International Space Station (ISS) is to test and demonstrate the viability and performance of Phase Change Material Heat Exchangers (PCM HX). The system was required to pump a working fluid through a PCM HX to promote the phase change material to freeze and thaw as expected on Orion's Multipurpose Crew Vehicle. Due to limitations on ISS's Internal Thermal Control System, a heat pump was needed on the Phase Change HX payload to help with reducing the working fluid's temperature to below 0degC (32degF). This paper will review the design and development of a TEC based liquid-liquid heat exchanger as a way to vary to fluid temperature for the freeze and thaw phase of the PCM HX. Specifically, the paper will review the design of custom coldplates and sizing for the required heat removal of the HX.

  9. Synthesis of Flexible Heat Exchanger Networks with Stream Splits Based on Rangers of Stream Supply Temperatures and Heat Capacity Flowrates

    Institute of Scientific and Technical Information of China (English)

    李志红; 罗行; 华贵; W.Roetzel

    2004-01-01

    A new superstructure model of heat exchanger networks (HEN) with stream splits based on rangers of streams supply temperatures and heat capacity flow rates is presented. The simultaneous optimal mathematical model of flexible HEN synthesis is established too. Firstly, the streams with rangers of supply temperatures and/or the streams with the rangers of heat capacity flow rates are pretreated; Secondly, several rules are proposed to establish the superstructure model of HEN with splits and the simultaneous optimal mathematical model of flexible HEN; Thirdly, the improving genetic algorithm is applied to solve the mathematical model established at the second step effectively, and the original optimal structure of HEN based on the maximum operation limiting condition can be obtained easily; Finally, the rules of heat exchange unit merged and the heat load of heat exchanger relaxed are presented, the flexible configuration of HEN satisfied the operation condition between the upper and down bounds of supply temperature and heat capacity flow rates can be obtained based on the original optimal structure of HEN by means of these rules. A case study demonstrates the method presented in this paper is effective

  10. Second law analysis of a plate heat exchanger with an axial dispersive wave

    Science.gov (United States)

    Kumar Das, Sarit; Roetzel, Wilfried

    A second law analysis is presented for thermally dispersive flow through a plate heat exchanger. It is well known that in plate or plate fin type heat exchangers the backmixing and other deviations from plug flow contribute significantly to the inefficiency of the heat exchanger, which is of importance to heat exchangers working in the cryogenic regime. The conventional axial heat dispersion model which is used so far is found to be better than `plug flow' model but still unsatisfactory where the timescale related to heat transfer is comparable with the thermal relaxation time for the propagation of dispersion. The present work therefore considers dispersion as a wave phenomenon propagating with a finite velocity. The study discusses the nature of variation of different contributions to total exergy loss in the heat exchanger with respect to dispersion parameters of the Peclet number and propagation velocity of the dispersive wave. The practical example of the single-pass plate heat exchanger demonstrates how a second law optimization can be carried out for heat transfer equipment under such conditions.

  11. Analyze single- and multiple-pass heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ratnam, R. (Univ. of Illinois, Urbana-Champagne, IL (United States)); Patwardhan, V.S. (National Chemical Lab., Poona (India))

    1993-06-01

    Heat exchanger calculations generally address the design problem (where for given process conditions and heat exchanger duty, a geometry is selected and the area is estimated) or they address the simulation problem (where for a given geometry, overall heat-transfer coefficient, and heat-transfer area, the heat duty and the outlet temperatures are determined). The latter is particularly useful when predicting the performance of heat exchanger networks. This article presents a novel graphical method that is suitable for design, simulation, and some operational studies, and is applicable to both single-pass and multipass heat exchangers. The main advantage of these graphs over earlier graphical representations is that they are uniformly applicable for a variety of problems. Although graphical techniques are useful for understanding underlying relationships, they are not suitable for computer implementation. However, these relationships can be computerized fairly easily.

  12. Principle of uniformity of temperature difference field in heat exchanger

    Institute of Scientific and Technical Information of China (English)

    过增元; 李志信; 周森泉; 熊大曦

    1996-01-01

    A principle of uniformity of temperature difference field (TDF) in heat exchangers is advanced.It states that the more uniform the temperature difference field,the higher the effectiveness of heat exchanger for a given NTU and C,.Analytical and numerical results on the uniformity of TDF and effectiveness of thirteen types of heat exchangers show the validity of the uniformity principle.Its further verification is given by the asymptotical solution of TDF in terms of a recurrence formula of heat transfer area distribution.The analyses of entropy generation caused by heat transfer indicate that the uniformity principle is based on the second law of thermodynamics.Two ways,redistributing heat transfer areas and varying the connection between tubes,are presented for the improvement of the uniformity of TDF and the consequent increase of effectiveness for crossflow heat exchangers.

  13. Heat exchanger with helical bundles of finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Eyking, H.J.

    1975-01-23

    The invention applies to a heat exchanger with helical bundles of tubes consisting of finned tubes separated by spacers. The spacers are designed as closed holding cylinders with holding devices for the tube bundles, each ot which surrounds a bundle of tubes. This construction serves to simplify the production process and to enable the use of the heat exchanger at higher loads.

  14. Design Calculation of Heat Exchanger of Reflooding Test

    Institute of Scientific and Technical Information of China (English)

    DUAN; Ming-hui; LI; Xiang; LI; Wei-qing

    2013-01-01

    The heat exchanger is very important to the major loop of the reflooding test.It can cool the fluid in the loop,so that the fluid temperature can agree with the requirements of the major pump and the preheater.Herein,an evaporative exchanger with U-shape tubes is adopted.The heat transfer calculation

  15. Heat Exchanger Network Retrofit Design by Eliminating Cross Pinch Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Beabu K. Piagbo

    2013-01-01

    Full Text Available The rising cost of energy and environmental concerns are leading the petrochemical industry to search for methods of reducing energy consumption in refinery operations. To address this issue the research presented in this paper explores retrofit design for increasing the energy efficiency of Crude Distillation Units (CDUs. The case study presented uses monitored plant data from the preheat section of the CDU in a Refinery in the Niger Delta region of Nigeria, West Africa. Aspen Energy Analyser® software developed by Aspen Technologies is used in the analysis of this data. The research findings suggest that a retrofit design eliminating all cross pinch heat exchangers is the best retrofit design in terms of improving the energy performance of CDUs. There was an 84.62% and 92.31% reduction in the number of the heat exchangers used and the number of shells respectively. There were 16.57%, 2.74%, and 13.98% reductions in the operating cost, capital cost, and total cost respectively. 3.68% of the area became available for heat transfer. These gains were achieved despite a 12.27% increase in the heating demand. This design is therefore recommended to be applied after additional cost consideration.

  16. Heat transfer analysis of underground U-type heat exchanger of ground source heat pump system.

    Science.gov (United States)

    Pei, Guihong; Zhang, Liyin

    2016-01-01

    Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions of a continuous and intermittent operation over 7 days on a GSHP with a single-well, single-U and double-U heat exchanger and the impact of single-U and double-U buried heat pipes on the surrounding rock-soil temperature field and the impact of intermittent operation and continuous operation on the outlet water temperature. The influence on the rock-soil temperature is approximately 13 % higher for the double-U heat exchanger than that of the single-U heat exchanger. The extracted energy of the intermittent operation is 36.44 kw·h higher than that of the continuous mode, although the running time is lower than that of continuous mode, over the course of 7 days. The thermal interference loss and quantity of heat exchanged for unit well depths at steady-state condition of 2.5 De, 3 De, 4 De, 4.5 De, 5 De, 5.5 De and 6 De of sidetube spacing are detailed in this work. The simulation results of seven working conditions are compared. It is recommended that the side-tube spacing of double-U underground pipes shall be greater than or equal to five times of outer diameter (borehole diameter: 180 mm).

  17. Cyclic high temperature heat storage using borehole heat exchangers

    Science.gov (United States)

    Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

    2016-04-01

    The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for

  18. The heat exchanger of small pellet boiler for phytomass

    Science.gov (United States)

    Mičieta, Jozef; Lenhard, Richard; Jandačka, Jozef

    2014-08-01

    Combustion of pellets from plant biomass (phytomass) causes various troubles. Main problem is slagging ash because of low melting temperature of ash from phytomass. This problem is possible to solve either improving energetic properties of phytomass by additives or modification of boiler construction. A small-scale boiler for phytomass is different in construction of heat exchanger and furnace mainly. We solve major problem - slagging ash, by decreasing combustion temperature via redesign of pellet burner and boiler body. Consequence of lower combustion temperature is also lower temperature gradient of combustion gas. It means that is necessary to design larger heat exchanging surface. We plane to use underfed burner, so we would utilize circle symmetry heat exchanger. Paper deals design of heat exchanger construction with help of CFD simulation. Our purpose is to keep uniform water flux and combustion gas flux in heat exchanger without zone of local overheating and excess cooling.

  19. A concept of PWR using plate and shell heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Luciano Ondir; Andrade, Delvonei Alves de, E-mail: luciano.ondir@gmail.com, E-mail: delvonei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    In previous work it was verified the physical possibility of using plate and shell heat exchangers for steam generation in a PWR for merchant ships. This work studies the possibility of using GESMEX commercial of the shelf plate and shell heat exchanger of series XPS. It was found it is feasible for this type of heat exchanger to meet operational and accidental requirements for steam generation in PWR. Additionally, it is proposed an arrangement of such heat exchangers inside the reactor pressure vessel. Such arrangement may avoid ANSI/ANS51.1 nuclear class I requirements on those heat exchangers because they are contained in the reactor coolant pressure barrier and play no role in accidental scenarios. Additionally, those plates work under compression, preventing the risk of rupture. Being considered non-nuclear safety, having a modular architecture and working under compression may turn such architectural choice a must to meet safety objectives with improved economics. (author)

  20. Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

    Science.gov (United States)

    Skupinski, Robert C.; Tower, Leonard K.; Madi, Frank J.; Brusk, Kevin D.

    1993-01-01

    The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed.

  1. Modeling of Heat Exchange with Developed Nucleate Boiling on Tenons

    Directory of Open Access Journals (Sweden)

    A. V. Оvsiannik

    2007-01-01

    Full Text Available The paper proposes a thermal and physical model for heat exchange processes with developed nucleate boiling on the developed surfaces (tenons with various contours of heat transfer surface. Dependences for calculating convective heat exchange factor have been obtained on the basis of modeling representation. Investigations have shown that an intensity of convective heat exchange does not depend on tenon profile when boiling takes place on the tenons. The intensity is determined by operating conditions, thermal and physical properties of liquid, internal characteristics of boiling processes and geometrical characteristics of a tenon.

  2. 基于状态空间超级结构的多流股换热网络最优设计%Optimal design of multistream heat exchanger network based on state space superstructure

    Institute of Scientific and Technical Information of China (English)

    李永强; 王兵; 邹雄; 董宏光; 姚平经

    2014-01-01

    多流股换热器以其结构紧凑、高效低耗等特点,成为过程强化研究的热门领域,但对于多流股换热的过程与设备优势所在仍然值得商榷。基于多流股换热匹配改进状态空间超级结构,将多流股换热网络综合转化为超级换热器设计。首先,构造级联多流股换热器匹配过程操作算子,通过相邻换热流股匹配,传递温位效应,实现多流股间传热严格计算;借助热容流率混合分配机制,实现各流股间任意分混操作。然后,考虑散热因素,改进目标函数,引入冷热损失和保温材料费用项,清晰体现多流股换热器因换热面互相覆盖而带来的外表面封包优势。进而,建立相应非线性数学规划模型,实现公用工程、设备投资、冷热损耗同步优化。最终,通过文献示例对所提方法可行性与优越性进行验证。%Multistream heat exchanger (MHEX) has attracted attention in the process intensification field with its compact structure, high efficiency and low heat loss. However, the potential advantages of its process and equipment are still worth discussing. An improved State-space superstructure based on MHEXs process operator (PO) was proposed to convert the network synthesis into a super-exchanger design. Hierarchy matching MHEXs PO was constructed, and the strict heat transfer calculation among multiple streams was implemented through temperature coordinated effect between adjacent streams. Arbitrary splitting and mixing of any stream was achieved by corresponding mixers and splitters in distribution network (DN). The objective function was ameliorated by taking heat loss into consideration. Through introducing the cost of heat loss and thermal insulation material, the external surface envelope advantage of MHEX was presented clearly owing to coverage between adjacent heat-transfer surfaces. Then, a corresponding nonlinear programming (NLP) mathematical model was

  3. Mapping Heat Exchange in an Allosteric Protein

    Science.gov (United States)

    Gupta, Shaweta; Auerbach, Anthony

    2011-01-01

    Nicotinic acetylcholine receptors (AChRs) are synaptic ion channels that spontaneously isomerize (i.e., gate) between resting and active conformations. We used single-molecule electrophysiology to measure the temperature dependencies of mouse neuromuscular AChR gating rate and equilibrium constants. From these we estimated free energy, enthalpy, and entropy changes caused by mutations of amino acids located between the transmitter binding sites and the middle of the membrane domain. The range of equilibrium enthalpy change (13.4 kcal/mol) was larger than for free energy change (5.5 kcal/mol at 25°C). For two residues, the slope of the rate-equilibrium free energy relationship (Φ) was approximately constant with temperature. Mutant cycle analysis showed that both free energies and enthalpies are additive for energetically independent mutations. We hypothesize that changes in energy associated with changes in structure mainly occur close to the site of the mutation, and, hence, that it is possible to make a residue-by-residue map of heat exchange in the AChR gating isomerization. The structural correlates of enthalpy changes are discussed for 12 different mutations in the protein. PMID:21320434

  4. An experimental study of a pin-fin heat exchanger

    OpenAIRE

    Ramthun, David L.

    2003-01-01

    Approved for public release; distribution is unlimited A detailed experimental study has been carried out on the heat transfer and pressure drop characteristics of a compact heat exchanger with pin fins. A modular wind-tunnel with a rectangular cross-section duct-flow area was constructed that would accommodate the heat exchanger test section with varying pin designs. The flow in the tunnel was achieved through a suction-type blower, and a leading entrance length section was added to achie...

  5. Heat Recovery Ventilation for Housing: Air-to-Air Heat Exchangers.

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

    The air-to-air heat exchanger (a fan powered ventilation device that recovers heat from stale outgoing air) is explained in this six-part publication. Topic areas addressed are: (1) the nature of air-to-air heat exchangers and how they work; (2) choosing and sizing the system; (3) installation, control, and maintenance of the system; (4) heat…

  6. Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles

    Directory of Open Access Journals (Sweden)

    S. Muthuraman

    2013-08-01

    Full Text Available - Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45°, 35°, and 20° were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressure drop increased proportionally with the mass flux and the vapor quality and inversely with the condensation temperature and the chevron angle.

  7. Exergy Transfer Characteristics on Low Temperature Heat Exchangers

    Science.gov (United States)

    Wu, S. Y.; Yuan, X. F.; Li, Y. R.; Peng, L.

    By analyzing exergy transfer process of the low temperature heat exchangers operating below the surrounding temperature, the concept of exergy transfer coefficient is put forward and the expressions which involving relevant variables for the exergy transfer coefficient, the heat transfer units number and the ratio of cold to hot fluids heat capacity rate, etc. are derived. Taking the parallel flow, counter flow and cross flow low temperature heat exchangers as examples, the numerical results of exergy transfer coefficient are given and the comparison of exergy transfer coefficient with heat transfer coefficient is analyzed.

  8. Development of micro-structured heat exchangers; Developpement d'echangeurs de chaleur microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Bouzon, C.

    2004-10-01

    This study has been carried out to defend the Technological Diploma of Research, in the aim to develop micro-structured heat exchangers. Realized within the Research Group on the Heat exchangers and Energy (GREThE) of the Atomic Energy Commission (CEA) of Grenoble. The rise of micro-technologies and the optimization of heat exchangers have led to emergence from few years of new structures of fluid paths with scales lower than the millimeter, thus making it possible to produce heat exchangers ultra-compacts. The micro-structured exchangers are heat exchangers whose hydraulic diameters are lower than the millimeter but with external dimensions of several centimeters. The study is based on two patents filed by the CEA and the characterization of these two geometries. A first concept of cross flow type finds applications with Gas/Liquid heat exchanger. A second type, a countercurrent, is more adapted to Liquid/Liquid applications. An approach with simplified analytical models and by numerical simulation was employed for each concept. An experimental study on the Gas/Liquid concept was also carried out. (author)

  9. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-12-01

    The U.S. Department of Energy selected the high temperature gas-cooled reactor as the basis for the Next Generation Nuclear Plant (NGNP). The NGNP will demonstrate the use of nuclear power for electricity, hydrogen production, and process heat applications. The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. An intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding. This report describes the preliminary results of a scoping study that evaluated the diffusion welding process parameters and the resultant mechanical properties of diffusion welded joints using Alloy 800H. The long-term goal of the program is to progress towards demonstration of small heat exchanger unit cells fabricated with diffusion welds. Demonstration through mechanical testing of the unit cells will support American Society of Mechanical Engineers rules and standards development, reduce technical risk, and provide proof of concept for heat exchanger fabrication methods needed to deploy heat exchangers in several potential NGNP configurations.1 Researchers also evaluated the usefulness of modern thermodynamic and diffusion computational tools (Thermo-Calc and Dictra) in optimizing the parameters for diffusion welding of Alloy 800H. The modeling efforts suggested a temperature of 1150 C for 1 hour with an applied pressure of 5 MPa using 15 {micro}m nickel foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved

  10. Effect of size sprinkled heat exchange surface on developing boiling

    Directory of Open Access Journals (Sweden)

    Petr Kracík

    2016-06-01

    Full Text Available This article presents research of sprinkled heat exchangers. This type of research has become rather topical in relation to sea water desalination. This process uses sprinkling of exchangers which rapidly separates vapour phase from a liquid phase. Applications help better utilize low-potential heat which is commonly wasted in utility systems. Low-potential heat may increase utilization of primary materials. Our ambition is to analyse and describe the whole sprinkled exchanger. Two heat exchangers were tested with a similar tube pitch: heat exchanger no. 1 had a four-tube bundle and heat exchanger no. 2 had eight-tube bundle. Efforts were made to maintain similar physical characteristics. They were tested at two flow rates (ca 0.07 and 0.11 kg s−1 m−1 and progress of boiling on the bundle was observed. Initial pressure was ca 10 kPa (abs at which no liquid was boiling at any part of the exchanger; the pressure was then lowered. Other input parameters were roughly similar for both flow rates. Temperature of heating water was ca 50°C at a constant flow rate of ca 7.2 L min−1. Results of our experiments provide optimum parameters for the given conditions for both tube bundles.

  11. Physical explosion analysis in heat exchanger network design

    Science.gov (United States)

    Pasha, M.; Zaini, D.; Shariff, A. M.

    2016-06-01

    The failure of shell and tube heat exchangers is being extensively experienced by the chemical process industries. This failure can create a loss of production for long time duration. Moreover, loss of containment through heat exchanger could potentially lead to a credible event such as fire, explosion and toxic release. There is a need to analyse the possible worst case effect originated from the loss of containment of the heat exchanger at the early design stage. Physical explosion analysis during the heat exchanger network design is presented in this work. Baker and Prugh explosion models are deployed for assessing the explosion effect. Microsoft Excel integrated with process design simulator through object linking and embedded (OLE) automation for this analysis. Aspen HYSYS V (8.0) used as a simulation platform in this work. A typical heat exchanger network of steam reforming and shift conversion process was presented as a case study. It is investigated from this analysis that overpressure generated from the physical explosion of each heat exchanger can be estimated in a more precise manner by using Prugh model. The present work could potentially assist the design engineer to identify the critical heat exchanger in the network at the preliminary design stage.

  12. Basic Principles for Calculating Heat Exchanger Characteristics under Conditions of Environmental Heat Losses

    Directory of Open Access Journals (Sweden)

    B. A. Bayrashevsky

    2007-01-01

    Full Text Available The paper considers two most characteristic models of heat exchange mechanisms in heaters with due account of environmental heat losses. As a result of executed investigations a list of corresponding engineering formulae has been developed which can be used for determination of heat engineering characteristics of heat exchangers and calculation of heating modes of their operation.Authors of the paper have elaborated a special «Heat Exchanger» programming file that corroborates reliability of the executed analysis and makes it possible to carry out a number of the required calculations.

  13. New gas-gas heat exchanger in silicon carbide for heat recovery from high temperature gases (1200/sup 0/C)

    Energy Technology Data Exchange (ETDEWEB)

    Galant, S.; Grouset, D.; Martinez, G.; Mulet, J.; Rebuffat, D. (Societe Bertin, 78 - Plaisir (France)); Minjolle, L. (Societe Ceraver, 75 - Paris (France))

    1984-06-01

    A study of a novel gas-gas ceramic heat exchanger is presented with main industrial end uses as a heat recovery systems on exhaust combustion gases to preheat the combustion air to furnace burners. Large overall heat transfer coefficients are obtained by using both radiative and jet impingement convective heat transfer. A silicium carbide plate design is chosen on the basis of existing large scale production capabilities. A 100 hour experimental test program is carried out successfully, which confirms thermodynamic calculations and good overall design: 4 year payback times are expected for a standard industrial case examined. Further optimization studies will aim at further reducing such preliminary values.

  14. Microchannel crossflow fluid heat exchanger and method for its fabrication

    Science.gov (United States)

    Swift, Gregory W.; Migliori, Albert; Wheatley, John C.

    1985-01-01

    A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance.

  15. The predictive protective control of the heat exchanger

    Science.gov (United States)

    Nevriva, Pavel; Filipova, Blanka; Vilimec, Ladislav

    2016-06-01

    The paper deals with the predictive control applied to flexible cogeneration energy system FES. FES was designed and developed by the VITKOVICE POWER ENGINEERING joint-stock company and represents a new solution of decentralized cogeneration energy sources. In FES, the heating medium is flue gas generated by combustion of a solid fuel. The heated medium is power gas, which is a gas mixture of air and water steam. Power gas is superheated in the main heat exchanger and led to gas turbines. To protect the main heat exchanger against damage by overheating, the novel predictive protective control based on the mathematical model of exchanger was developed. The paper describes the principle, the design and the simulation of the predictive protective method applied to main heat exchanger of FES.

  16. The influence of heat exchanger design on the synthesis of heat exchanger networks

    Directory of Open Access Journals (Sweden)

    Liporace F.S.

    2000-01-01

    Full Text Available Heat exchanger network (HEN synthesis has been traditionally performed without accounting for a more detailed unit design, which is important since the final HEN may require unfeasible units. Recently, publications on this matter have appeared, as well as softwares that simultaneously perform synthesis and units design. However, these publications do not clearly show the influence of the new added features on the final HEN. Hence, this work aims at showing that units' design can strongly affect the final HEN. Improvements on heat transfer area and total annual cost estimations, which influence the HEN structural evolution, are the main responsible for that. It is also shown the influence of some design bounds settings, which can indicate an unfeasible unit design and, therefore, the need for a new match search or the maintenance of a loop. An example reported in the literature is used to illustrate the discussion.

  17. Optimization of Gas Turbine Cogeneration Systemfor Various Heat Exchanger Configurations Optimisation des systèmes de turbine à combustion en cogénération pour différentes configurations des échangeurs de chaleur

    Directory of Open Access Journals (Sweden)

    Costea M.

    2011-11-01

    Full Text Available The present paper investigates and compares the performance of three configurations of Gas Turbine systems allowing cogeneration of heat and electricity, on the basis of an irreversible regenerative Brayton-Joule cycle. The proposed model is developed for two different cycle constraints, namely, an imposed heat transfer rate released by the fuel combustion, or an imposed maximum cycle temperature. The model also includes the irreversibility due to the friction in the compressor and turbine, and due to the heat losses in the combustion chamber and heat exchangers. Energy efficiency for the system without and with cogeneration, and the exergetic efficiency are used in order to emphasize the cogeneration advantages, but also to help the designer to choose the best configuration of the Gas Turbine system that suits to his needs. Experimental data from a real operating microturbine were used to validate the model. The power output and the energy and exergetic efficiencies are optimized with respect to a set of operating parameters. The optimum values of the Gas Turbine engine parameters corresponding to maximum power output and respectively to maximum thermodynamic efficiency are discussed. The results show same optimal values of the compression ratio corresponding to almost all maximum performances for an imposed heat transfer rate released by the fuel combustion, excepting the maximum exergetic efficiency that requires higher optimal values of the compression ratio than the maximum exergy rate one. A performance comparison of the three configurations is done and future perspectives of the work are proposed. Cet article explore et compare les performances des trois configurations de systèmes de turbine à combustion permettant la production combinée de chaleur et d’électricité, sur la base du cycle irréversible régénératif de Brayton-Joule. Le modèle proposé est développé pour deux contraintes différentes sur le cycle, notamment le

  18. Temperatures and Heat Flows in a Soil Enclosing a Slinky Horizontal Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Pavel Neuberger

    2014-02-01

    Full Text Available Temperature changes and heat flows in soils that host “slinky”-type horizontal heat exchangers are complex, but need to be understood if robust quantification of the thermal energy available to a ground-source heat pump is to be achieved. Of particular interest is the capacity of the thermal energy content of the soil to regenerate when the heat exchangers are not operating. Analysis of specific heat flows and the specific thermal energy regime within the soil, including that captured by the heat-exchangers, has been characterised by meticulous measurements. These reveal that high concentrations of antifreeze mix in the heat-transfer fluid of the heat exchanger have an adverse impact on heat flows discharged into the soil.

  19. A Semi-Instantaneous Heat Exchanger for Mobile Solar Collectors Test System

    Directory of Open Access Journals (Sweden)

    Haifeng Cao

    2013-07-01

    Full Text Available A semi-instantaneous heat exchanger which can solve low efficiency and space shortage of mobil test system for thermal performance of solar collectors is proposed in this paper, In this paper, the structure parameters of heat exchanger and the power of heat resistance are designed based on the method of mean temperature difference. The experiment results show the performance of test system has been optimized. The efficiency of collectors test can be increased 50% and the total weight of the primary heater and working medium is reduced to 13.8%.The load of the test vehicle and occupancy volume have been decreased.

  20. Design and evaluation of a heat pipe exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C.H.; Zeigler, E.

    1982-06-01

    A promising approach to energy conservation is the use of heat pipes to recover heat now lost in effluent processing wastewater streams. At Radford Army Ammunition Plant a prototype water-to-water heat pipe heat exchanger (HPHX) was evaluated. Heat was extracted from wastewater and recovered heat then used to preheat incoming fresh water. The heat pipe is schematicized. Design objectives--access to wasterwater section, provision for periodic inspection--are specified. Based on these objectives the HPHX design is shown. A performance analysis is carried out by means of equations. Based on mobilization rates at Radford, a savings of significant amount will be realized.

  1. Constructal design of finned tubes used in air-cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Shokouhmand, Hossein; Mahjoub, Shoeib [University of Tehran, Tehran (Iran, Islamic Republic of); Salimpour, Mohammad Reza [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2014-06-15

    The present study documents the constructal design and optimization of finned tubes used in air-cooled heat exchangers. The considered tubes are equipped with annular fins. The aim is to minimize the overall thermal resistance by morphing the geometry. The geometrical and thermo-physical parameters considered are the number of fins, ratio of fin height to tube diameter, Stanton number, ratio of fin conductivity to air conductivity, ratio of in-tube fluid conductivity to air conductivity and dimensionless pressure drop. Two constraints are applied in the optimization process: fixed overall volume of heat exchanger and fixed volume fraction of fin material. It is found that there exist optimal values for the number and the height of fins. Moreover, the optimal heat transfer has an extremum in a special volume fraction of fin material.

  2. Control strategies in a thermal oil - Molten salt heat exchanger

    Science.gov (United States)

    Roca, Lidia; Bonilla, Javier; Rodríguez-García, Margarita M.; Palenzuela, Patricia; de la Calle, Alberto; Valenzuela, Loreto

    2016-05-01

    This paper presents a preliminary control scheme for a molten salt - thermal oil heat exchanger. This controller regulates the molten salt mass flow rate to reach and maintain the desired thermal oil temperature at the outlet of the heat exchanger. The controller architecture has been tested using an object-oriented heat exchanger model that has been validated with data from a molten salt testing facility located at CIEMAT-PSA. Different simulations are presented with three different goals: i) to analyze the controller response in the presence of disturbances, ii) to demonstrate the benefits of designing a setpoint generator and iii) to show the controller potential against electricity price variations.

  3. Determination Global Heat Transfer Coefficient in Shell and Tube Type and Plates Heat Exchangers

    OpenAIRE

    Duarte, José Arnaldo

    2012-01-01

    The literature on heat exchangers is very wide because of numerous existing configurations, several types of fluids used, as well as the variety of applications. On the other hand, when we need to calculate a heat exchanger, a similar procedure is hardly found. Therefore, we propose this educational work in order to facilitate the calculation procedures, when the student or the professional in the area needs a script for its design. The heat exchanger is installed in the Laboratory of Thermal...

  4. Experimental determination of correlations for mean heat transfer coefficients in plate fin and tube heat exchangers

    Science.gov (United States)

    Taler, Dawid

    2012-09-01

    This paper presents a numerical method for determining heat transfer coefficients in cross-flow heat exchangers with extended heat exchange surfaces. Coefficients in the correlations defining heat transfer on the liquid- and air-side were determined using a nonlinear regression method. Correlation coefficients were determined from the condition that the sum of squared liquid and air temperature differences at the heat exchanger outlet, obtained by measurements and those calculated, achieved minimum. Minimum of the sum of the squares was found using the Levenberg-Marquardt method. The uncertainty in estimated parameters was determined using the error propagation rule by Gauss. The outlet temperature of the liquid and air leaving the heat exchanger was calculated using the analytical model of the heat exchanger.

  5. Low Cost Polymer heat Exchangers for Condensing Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Thomas [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, Rebecca [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, George [Brookhaven National Lab. (BNL), Upton, NY (United States); Worek, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  6. EVALUASI KINERJA HEAT EXCHANGER DENGAN METODE FOULING F

    Directory of Open Access Journals (Sweden)

    Bambang Setyoko

    2012-02-01

    Full Text Available The performance of heat exchangers usually deteriorates with time as a result of accumulation of depositson heat transfer surfaces. The layer of deposits represents additional resistance to heat transfer and causesthe rate of heat transfer in a heat exchanger to decrease. The net effect of these accumulations on heattransfer is represented by a fouling factor Rf , which is a measure of the thermal resistance introduced byfouling.In this case, the type of fouling is the precipitation of solid deposits in a fluid on the heat transfer surface.The mineral deposits forming on the inner and the outer surfaces of fine tubes in the heat exchanger. Thefouling factor is increases with time as the solid deposits build up on the heat exchanger surface. Foulingincreases with increasing temperature and decreasing velocity.In this research, we obtain the coefisien clean overal 5,93 BTU/h.ft2.oF, Dirt factor 0,004 BTU/h.ft2 0F,Pressure drope in tube 2,84 . 10-3 Psi and pressure drope in shell 4,93 . 10-4 Psi.This result are less thanthe standard of parameter. Its means this Heat exchanger still clean relativity and can operate continousslywithout cleaning.

  7. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    Energy Technology Data Exchange (ETDEWEB)

    DR. DENNIS NAGLE; DR. DAJIE ZHANG

    2009-03-26

    Silicon carbide (SiC) materials are prime candidates for high temperature heat exchangers for next generation nuclear reactors due to their refractory nature and high thermal conductivity at elevated temperatures. This research has focused on demonstrating the potential of liquid silicon infiltration (LSI) for making SiC to achieve this goal. The major advantage of this method over other ceramic processing techniques is the enhanced capability of making high dense, high purity SiC materials in complex net shapes. For successful formation of net shape SiC using LSI techniques, the carbon preform reactivity and pore structure must be controlled to allow the complete infiltration of the porous carbon structure which allows complete conversion of the carbon to SiC. We have established a procedure for achieving desirable carbon properties by using carbon precursors consisting of two readily available high purity organic materials, crystalline cellulose and phenolic resin. Phenolic resin yields a glassy carbon with low chemical reactivity and porosity while the cellulose carbon is highly reactive and porous. By adjusting the ratio of these two materials in the precursor mixtures, the properties of the carbons produced can be controlled. We have identified the most favorable carbon precursor composition to be a cellulose resin mass ratio of 6:4 for LSI formation of SiC. The optimum reaction conditions are a temperature of 1800 C, a pressure of 0.5 Torr of argon, and a time of 120 minutes. The fully dense net shape SiC material produced has a density of 2.96 g cm{sup -3} (about 92% of pure SiC) and a SiC volume fraction of over 0.82. Kinetics of the LSI SiC formation process was studied by optical microscopy and quantitative digital image analysis. This study identified six reaction stages and provided important understanding of the process. Although the thermal conductivity of pure SiC at elevated temperatures is very high, thermal conductivities of most commercial Si

  8. SILICON CARBIDE CERAMICS FOR COMPACT HEAT EXCHANGERS

    Energy Technology Data Exchange (ETDEWEB)

    DR. DENNIS NAGLE; DR. DAJIE ZHANG

    2009-03-26

    Silicon carbide (SiC) materials are prime candidates for high temperature heat exchangers for next generation nuclear reactors due to their refractory nature and high thermal conductivity at elevated temperatures. This research has focused on demonstrating the potential of liquid silicon infiltration (LSI) for making SiC to achieve this goal. The major advantage of this method over other ceramic processing techniques is the enhanced capability of making high dense, high purity SiC materials in complex net shapes. For successful formation of net shape SiC using LSI techniques, the carbon preform reactivity and pore structure must be controlled to allow the complete infiltration of the porous carbon structure which allows complete conversion of the carbon to SiC. We have established a procedure for achieving desirable carbon properties by using carbon precursors consisting of two readily available high purity organic materials, crystalline cellulose and phenolic resin. Phenolic resin yields a glassy carbon with low chemical reactivity and porosity while the cellulose carbon is highly reactive and porous. By adjusting the ratio of these two materials in the precursor mixtures, the properties of the carbons produced can be controlled. We have identified the most favorable carbon precursor composition to be a cellulose resin mass ratio of 6:4 for LSI formation of SiC. The optimum reaction conditions are a temperature of 1800 C, a pressure of 0.5 Torr of argon, and a time of 120 minutes. The fully dense net shape SiC material produced has a density of 2.96 g cm{sup -3} (about 92% of pure SiC) and a SiC volume fraction of over 0.82. Kinetics of the LSI SiC formation process was studied by optical microscopy and quantitative digital image analysis. This study identified six reaction stages and provided important understanding of the process. Although the thermal conductivity of pure SiC at elevated temperatures is very high, thermal conductivities of most commercial Si

  9. Active latent heat storage with a screw heat exchanger - experimental results for heat transfer and concept for high pressure steam

    Science.gov (United States)

    Zipf, Verena; Willert, Daniel; Neuhäuser, Anton

    2016-05-01

    An innovative active latent heat storage concept was invented and developed at Fraunhofer ISE. It uses a screw heat exchanger (SHE) for the phase change during the transport of a phase change material (PCM) from a cold to a hot tank or vice versa. This separates heat transfer and storage tank in comparison to existing concepts. A test rig has been built in order to investigate the heat transfer coefficients of the SHE during melting and crystallization of the PCM. The knowledge of these characteristics is crucial in order to assess the performance of the latent heat storage in a thermal system. The test rig contains a double shafted SHE, which is heated or cooled with thermal oil. The overall heat transfer coefficient U and the convective heat transfer coefficient on the PCM side hPCM both for charging and discharging have been calculated based on the measured data. For charging, the overall heat transfer coefficient in the tested SHE was Uch = 308 W/m2K and for discharging Udis = 210 W/m2K. Based on the values for hPCM the overall heat transfer coefficients for a larger SHE with steam as heat transfer fluid and an optimized geometry were calculated with Uch = 320 W/m2K for charging and Udis = 243 W/m2K for discharging. For pressures as high as p = 100 bar, an SHE concept has been developed, which uses an organic fluid inside the flight of the SHE as working media. With this concept, the SHE can also be deployed for very high pressure, e.g. as storage in solar thermal power plants.

  10. Numerical Analysis of Tube-Fin Heat Exchanger using Fluent

    Directory of Open Access Journals (Sweden)

    M. V. Ghori

    2012-08-01

    Full Text Available Three-dimensional CFD simulations are carried out to investigate heat transfer and fluid flow characteristics of two-row plain Tube and Fin heat exchanger using FLUENT software. Heat transfer and pressure drop characteristics of the heat exchanger are investigated for Reynolds numbers ranging from 330 to 7000. Model geometry is created and meshed by using GAMBIT software. Fluid flow and heat transfer are simulated and results compared using both laminar and turbulent flow models k-, and SST k-omega, with steady-state solvers to calculate pressure drop, flow, and temperature fields. Model validation is carried out by comparing the simulated value friction factor f and Colburn factor j to experimental results investigate by Wang. Reasonable agreement is found between the simulations and experimental data, and the fluent software has been sufficient for simulating the flow fields in tube-fin heat exchangers.

  11. Thermal design heat sinks, thermoelectrics, heat pipes, compact heat exchangers, and solar cells

    CERN Document Server

    Lee, H S

    2010-01-01

    The proposed is written as a senior undergraduate or the first-year graduate textbook,covering modern thermal devices such as heat sinks, thermoelectric generators and coolers, heat pipes, and heat exchangers as design components in larger systems. These devices are becoming increasingly important and fundamental in thermal design across such diverse areas as microelectronic cooling, green or thermal energy conversion, and thermal control and management in space, etc. However, there is no textbook available covering this range of topics. The proposed book may be used as a capstone design cours

  12. 球面弓形折流板换热器折流板曲率半径的优化研究%Optimization Research of Baffle Curvature Radius in Spherical Baffle Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    郭土; 马贵阳; 张一楠; 孙皓; 曹燕龙

    2013-01-01

    In order to research the influence of the spherical baffle heat exchanger’s baffle curvature radius to the shell side pressure drop and the coefficient of heat transfer, shell side fluid flow condition and heat exchanger performance of the spherical baffle heat exchangers with curvature radius of 0.75D,1D,1.25D or 1.5D and conventional segmental baffle heat exchangers were numerically analyzed and studied. The shell side fluid flow field distribution, shell side pressure drop and coefficient of heat transfer were obtained. The results indicate that, under the same inlet flow conditions, the smaller of the baffle curvature radius,the bigger of comprehensive performance index of the heat exchanger’s shell side heat transfer and flow resistance, the comprehensive performance index of the spherical baffle heat exchanger with curvature radius of 0.75D is higher by 8.5%than that of the conventional segmental baffle heat exchanger.%为了研究球面弓形折流板换热器折流板曲率半径对换热器壳程压降和换热系数的影响,对曲率半径分别为0.75D、1D、1.25D、1.5D 的球面弓形折流板换热器和普通弓形折流板换热器的壳侧流体流动与传热性能进行数值模拟与研究,得到了壳程流体流场分布以及壳程压降和传热系数。研究结果表明在相同入口流速下,曲率半径越小换热器壳程传热与流阻综合性能指标越大,0.75D 球面弓形折流板换热器可比普通弓形折流板换热器提高8.5%左右。

  13. Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, B.J.; White, M.J.; Klebaner, A.; /Fermilab

    2011-06-10

    Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the design of compact and high-effectiveness cryogenic heat exchangers operating at liquid helium temperatures requires consideration of axial heat conduction along the direction of flow, in addition to variable fluid properties. Here we present a numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger. The model is used to guide design decisions on heat exchanger material choice and geometry. In addition, the J-T expansion process is modeled with the heat exchanger to analyze the effect of heat load and cryogenic supply parameters. A numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger was developed and the effect of various design parameters on overall heat exchanger size was investigated. It was found that highly conductive metals should be avoided in the design of compact JT heat exchangers. For the geometry considered, the optimal conductivity is around 3.5 W/m-K and can range from 0.3-10 W/m-K without a large loss in performance. The model was implemented with an isenthalpic expansion process. Increasing the cold side inlet temperature from 2K to 2.2 K decreased the liquid fraction from 0.856 to 0.839 which corresponds to a 0.12 g/s increase in supercritical helium supply needed to maintain liquid level in the cooling bath. Lastly, it was found that the effectiveness increased when the heat load was below the design value. Therefore, the heat exchanger

  14. Simulation of heat exchanger network (HEN) and planning the optimum cleaning schedule

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr [Energy Systems Improvement Laboratory, Mechanical Engineering Department, Iran University of Science and Technology (IUST), Narmak, Tehran 16488 (Iran, Islamic Republic of)]. E-mail: sepehr@iust.ac.ir; Niroomand, Behzad [Energy Systems Improvement Laboratory, Mechanical Engineering Department, Iran University of Science and Technology (IUST), Narmak, Tehran 16488 (Iran, Islamic Republic of)

    2007-05-15

    Modeling and simulation of heat exchanger networks for estimating the amount of fouling, variations in overall heat transfer coefficient, and variations in outlet temperatures of hot and cold streams has a significant effect on production analysis. In this analysis, parameters such as the exchangers' types and arrangements, their heat transfer surface areas, mass flow rates of hot and cold streams, heat transfer coefficients and variations of fouling with time are required input data. The main goal is to find the variations of the outlet temperatures of the hot and cold streams with time to plan the optimum cleaning schedule of heat exchangers that provides the minimum operational cost or maximum amount of savings. In this paper, the simulation of heat exchanger networks is performed by choosing an asymptotic fouling function. Two main parameters in the asymptotic fouling formation model, i.e. the decay time of fouling formation ({tau}) and the asymptotic fouling resistance (R{sub f}{sup {approx}}) were obtained from empirical data as input parameters to the simulation relations. These data were extracted from the technical history sheets of the Khorasan Petrochemical Plant to guaranty the consistency between our model outputs and the real operating conditions. The output results of the software program developed, including the variations with time of the outlet temperatures of the hot and cold streams, the heat transfer coefficient and the heat transfer rate in the exchangers, are presented for two case studies. Then, an objective function (operational cost) was defined, and the optimal cleaning schedule of the HEN (heat exchanger network) in the Urea and Ammonia units were found by minimizing the objective function using a numerical search method. Based on this minimization procedure, the decision was made whether a heat exchanger should be cleaned or continue to operate. The final result was the most cost effective plan for the HEN cleaning schedule. The

  15. Process Heat Exchanger Options for the Advanced High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-06-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  16. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-04-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  17. Heat pipe heat exchanger and its potential to energy recovery in the tropics

    Directory of Open Access Journals (Sweden)

    Yau Yat H.

    2015-01-01

    Full Text Available The heat recovery by the heat pipe heat exchangers was studied in the tropics. Heat pipe heat exchangers with two, four, six, and eight numbers of rows were examined for this purpose. The coil face velocity was set at 2 m/s and the temperature of return air was kept at 24°C in this study. The performance of the heat pipe heat exchangers was recorded during the one week of operation (168 hours to examine the performance data. Then, the collected data from the one week of operation were used to estimate the amount of energy recovered by the heat pipe heat exchangers annually. The effect of the inside design temperature and the coil face velocity on the energy recovery for a typical heat pipe heat exchanger was also investigated. In addition, heat pipe heat exchangers were simulated based on the effectiveness-NTU method, and their theoretical values for the thermal performance were compared with the experimental results.

  18. Heat Pipe Heat Exchangers with Double Isolation Layers for Prevention of Interpath Leakage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Cooling Technologies, Inc. (ACT), supported by Hamilton Sundstrand, proposes to develop a heat pipe heat exchanger that is low mass and provides two levels...

  19. Heat Pipe Heat Exchangers with Double Isolation Layers for Prevention of Interpath Leakage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Current manned spacecraft heat rejection systems use two heat exchangers and an intermediate fluid loop to provide isolation between the crew compartment air and the...

  20. Topology optimization for transient heat transfer problems

    DEFF Research Database (Denmark)

    Zeidan, Said; Sigmund, Ole; Lazarov, Boyan Stefanov

    The focus of this work is on passive control of transient heat transfer problems using the topology optimization (TopOpt) method [1]. The goal is to find distributions of a limited amount of phase change material (PCM), within a given design domain, which optimizes the heat energy storage [2]. Our......, TopOpt has later been extended to transient problems in mechanics and photonics (e.g. [5], [6] and [7]). In the presented approach, the optimization is gradient-based, where in each iteration the non-steady heat conduction equation is solved,using the finite element method and an appropriate time...

  1. On Effectiveness and Entropy Generatioin in Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    XiongDaxi; LiZhixin; 等

    1996-01-01

    Some conceptual problems were discussed in the present paper,Firstly,according to the physical meaning of effectiveness,a new expression of effectiveness was developed by using an ideal heat exchnager model and temperature histogram method,in which the non-uniform inlet temperature profile was considered.Secondly,the relation of entropy generation number to effectiveness was studied,it was pointed out that both of them could express the perfect degree of a heat exchanger to the second thermodynamic law.Finally,to describe both quantity and quality of heat transferred in a heat exchanger a criterion named as comperhensive thermal performance coefficient (CTPE) was presented.

  2. Nosehouse: heat-conserving ventilators based on nasal counterflow exchangers.

    Science.gov (United States)

    Vogel, Steven

    2009-12-01

    Small birds and mammals commonly minimize respiratory heat loss with reciprocating counterflow exchangers in their nasal passageways. These animals extract heat from the air in an exhalation to warm those passageways and then use that heat to warm the subsequent inhalation. Although the near-constant volume of buildings precludes direct application of the device, a pair of such exchangers located remotely from each other circumvents that problem. A very simple and crudely constructed small-scale physical model of the device worked well enough as a heat conserver to suggest utility as a ventilator for buildings.

  3. Development of Structure Optimization of Tube Bundle in the Shell and Tube Heat Exchanger%管壳式换热器管束结构优化发展概述

    Institute of Scientific and Technical Information of China (English)

    郝国永; 张莹莹; 高磊; 于宵航; 吴亮

    2014-01-01

    总结了近年来国内外新型管壳式换热器的管束结构发展进展,从管程、壳程两个方面介绍了管壳式换热器管束结构改进及强化传热机理,并且介绍了几种新型结构在实际生产中的成功应用及其强化传热特点。最后为换热器管束结构发展提出建设性意见。%The development progress in new tube bundle structure of shell and tube heat exchanger in recent years at home and abroad was summed up. Structure improvement and strengthening heat transfer mechanism of the shell and tube heat exchanger were introduced from two aspects of tube and shell. And successful application of several new structures in the actual production and its enhanced heat transfer characteristics were introduced. Finally, constructive suggestions about tube bundle structure development of the heat exchanger were put forward.

  4. A simplified model of heat transfer in heat exchangers and stack plates of thermoacoustic refrigerators

    Science.gov (United States)

    Herman, Cila; Chen, Yuwen

    2006-08-01

    A simplified model of heat transfer was developed to investigate the thermal behavior of heat exchangers and stack plates of thermoacoustic devices. The model took advantage of previous results describing the thermal behavior of the thermoacoustic core and heat transfer in oscillating flow to study the performance of heat exchangers attached to the core. The configuration considered is a flat tube (with a working fluid flowing in the tube) of the thickness of the stack plate attached to both ends of the stack plate. Geometrical and operational parameters as well as thermophysical properties of the heat exchangers, transport fluids in the heat exchangers, stack plate and the thermoacoustic working fluid were organized into dimensionless groups that allowed accounting for their impact on the performance of the heat exchangers. Two types of thermal boundary conditions were considered: constant temperature and constant heat flux along the heat exchanger tubes. Numerical simulations were carried out with the model introduced in the paper. The temperature distributions and heat fluxes near the edge of the stack plate were found to be nonlinear. The influence of system parameters on the thermal performance of the heat exchangers was analyzed.

  5. Exergetic efficiency optimization for an irreversible heat pump working on reversed Brayton cycle

    Indian Academy of Sciences (India)

    Yuehong Bi; Lingen Chen; Fengrui Sun

    2010-03-01

    This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is defined as the ratio of rate of exergy output to rate of exergy input of the system. The irreversibilities considered in the system include heat resistance losses in the hot- and cold-side heat exchangers and non-isentropic losses in the compression and expansion processes. The analytical formulas of the heating load, coefficient of performance (COP) and exergetic efficiency for the heat pumps are derived. The results are compared with those obtained for the traditional heating load and coefficient of performance objectives. The influences of the pressure ratio of the compressor, the allocation of heat exchanger inventory, the temperature ratio of two reservoirs, the effectiveness of the hot- and cold-side heat exchangers and regenerator, the efficiencies of the compressor and expander, the ratio of hot-side heat reservoir temperature to ambient temperature, the total heat exchanger inventory, and the heat capacity rate of the working fluid on the exergetic efficiency of the heat pumps are analysed by numerical calculations. The results show that the exergetic efficiency optimization is an important and effective criterion for the evaluation of an irreversible heat pump working on reversed Brayton cycle.

  6. Heat exchanger identification by using iterative fuzzy observers

    Science.gov (United States)

    Lalot, Sylvain; Guðmundsson, Oddgeir; Pálsson, Halldór; Pálsson, Ólafur Pétur

    2016-05-01

    The principle of fuzzy observers is first illustrated on a general example: the determination of the two parameters of second order systems using a step response. The set of equations describing the system are presented and it is shown that accurate results are obtained, even for a high level of noise. The heat exchanger model is then introduced. It is based on a spatial division of a counter flow heat exchanger into multiple sections. The governing equations are rewritten as a state space representation. The number of sections needed to get accurate results is determined by comparing estimated values to experimental data. Based on the mean value of the root mean squared errors, it is shown that 80 sections is an appropriate value for this heat exchanger. It is then shown that the iterative fuzzy observers can be used to determine the main parameters of the counter flow heat exchanger, i.e. the convection heat transfer coefficients, when in transient state. The final values of these parameters are heat transfer coefficient corresponds to a ±0.5 % variation of the estimated overall heat transfer coefficient. This study also shows that the fuzzy observers are equally efficient when the heat exchanger is in steady state.

  7. Various methods to improve heat transfer in exchangers

    Directory of Open Access Journals (Sweden)

    Pavel Zitek

    2015-01-01

    Full Text Available The University of West Bohemia in Pilsen (Department of Power System Engineering is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors. For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production. In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

  8. High Effectiveness Heat Exchanger for Cryogenic Refrigerators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an innovative high performance cryogenic heat exchanger manufactured of titanium by photo-etching and diffusion bonding. This is a parallel plate design...

  9. 1-MWE heat exchangers for OTEC. Final design report

    Energy Technology Data Exchange (ETDEWEB)

    Sprouse, A.M.

    1980-06-19

    The design of a 1 MWe OTEC heat exchanger is documented, including the designs of the evaporator and associated systems, condenser, instrumentation, and materials for corrosion/erosion control and fabrication processes. (LEW)

  10. Various methods to improve heat transfer in exchangers

    Science.gov (United States)

    Pavel, Zitek; Vaclav, Valenta

    2015-05-01

    The University of West Bohemia in Pilsen (Department of Power System Engineering) is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors). For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production). In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

  11. Phase Change Material (PCM) Heat Exchanger Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Project has identified two PCM HX concepts that will be designed, developed and demonstrated on-board the International Space Station (ISS):The first heat exchanger...

  12. Humidification on Ventilated Patients: Heated Humidifications or Heat and Moisture Exchangers?

    Science.gov (United States)

    Cerpa, F; Cáceres, D; Romero-Dapueto, C; Giugliano-Jaramillo, C; Pérez, R; Budini, H; Hidalgo, V; Gutiérrez, T; Molina, J; Keymer, J

    2015-01-01

    The normal physiology of conditioning of inspired gases is altered when the patient requires an artificial airway access and an invasive mechanical ventilation (IMV). The endotracheal tube (ETT) removes the natural mechanisms of filtration, humidification and warming of inspired air. Despite the noninvasive ventilation (NIMV) in the upper airways, humidification of inspired gas may not be optimal mainly due to the high flow that is being created by the leakage compensation, among other aspects. Any moisture and heating deficit is compensated by the large airways of the tracheobronchial tree, these are poorly suited for this task, which alters mucociliary function, quality of secretions, and homeostasis gas exchange system. To avoid the occurrence of these events, external devices that provide humidification, heating and filtration have been developed, with different degrees of evidence that support their use.

  13. Oil Circulation Effects on Evaporation Heat Transfer in Brazed Plate Heat Exchanger using R134A

    OpenAIRE

    Jang, Jaekyoo; Chang, Youngsoo; Kang, Byungha

    2012-01-01

    Experimental study was performed for oil circulation effects on evaporation heat transfer in the brazed type plate heat exchangers using R134A. In this study, distribution device was installed to ensure uniform flow distribution in the refrigerant flow passage, which enhances heat transfer performance of plate type heat exchanger. Tests were conducted for three evaporation temperature; 33℃, 37℃, and 41℃ and several oil circulation conditions. The nominal conditions of refrigerant are as follo...

  14. Analysis of the Technological Parameters of the Heat Exchanger in the Heating Pipe

    Directory of Open Access Journals (Sweden)

    Knyazev Vladimir

    2017-01-01

    Full Text Available The main purpose of this article is to analyze the selecting of technological parameters for the heat exchanger to improve the heat transfer and reduce the noise during operation in the heating pipe, which is used in the different systems of the planes and helicopters. In result of this study, the best technical parameters are found, considering different variations of deformation cutting heat exchanger pipes.

  15. An engineering procedure for air side performance evaluation of flat tube heat exchangers with louvered fins

    Science.gov (United States)

    Antonijevic, Dragi

    2013-01-01

    An accurate evaluation of possible air side heat transfer surface geometries is a prerequisite for optimal heat exchanger design. Aiming for practical engineering applicability a simplified and transparent analytical procedure for the assessment of louvered fin and flat tube heat exchanger geometries and the calculation of fin parameters that enable maximal performance for given boundary conditions has been developed. The proposed method comprises determining fins temperature profiles and effective heat transfer temperature difference, introduction of a relative heat transfer surface area, as well as the utilization of recent experimentally obtained heat transfer correlations confirmed for the observed range of boundary conditions. The proposed methodology is validated through comparison with experimental and numerical results of other authors.

  16. Optimal Heating in Heat-Treatment Process Based on Grey Asynchronous Particle Swarm Optimization

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    To ensure plate heating quality and reduce energy consumption in heat-treatment process, optimal heating for plates in a roller hearth furnace was investigated and a new strategy for heating procedure optimization was developed. During solving process, plate temperature forecast model based on heat transfer mechanics was established to calculate plate temperature with the assumed heating procedure. In addition, multi-objective feature of optimal heating was analyzed. And the method, which is composed of asynchronous particle swarm optimization and grey relational analysis, was adopted for solving the multi-objective problem. The developed strategy for optimizing heating has been applied to the mass production. The result indicates that the absolute plate discharging temperature deviation between measured value and target value does not exceed ± 8 ℃, and the relative deviation is less than ± 0.77%.

  17. Thermal performance modeling of cross-flow heat exchangers

    CERN Document Server

    Cabezas-Gómez, Luben; Saíz-Jabardo, José Maria

    2014-01-01

    This monograph introduces a numerical computational methodology for thermal performance modeling of cross-flow heat exchangers, with applications in chemical, refrigeration and automobile industries. This methodology allows obtaining effectiveness-number of transfer units (e-NTU) data and has been used for simulating several standard and complex flow arrangements configurations of cross-flow heat exchangers. Simulated results have been validated through comparisons with results from available exact and approximate analytical solutions. Very accurate results have been obtained over wide ranges

  18. Fin Distance Effect at Tube-Fin Heat Exchanger

    Science.gov (United States)

    Lemfeld, F.; Muller, M.; Frana, K.

    2013-04-01

    Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  19. Fin Distance Effect at Tube-Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Frana K.

    2013-04-01

    Full Text Available Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  20. Utilization of Additive Manufacturing for Aerospace Heat Exchangers

    Science.gov (United States)

    2016-02-29

    A Game Changer for the Manufacturing Industry?" Rolandberger.com. Nov. 2013. Web. <http://www.rolandberger.com/ media /pdf...hub/Advantages-and-Disadvantages-of-Shell-and- T ube-Piate-type-Heat -Exchangers>. " Arithmetic and Logarithmic Mean Temperature Difference...34 Arithmetic and Logarithmic Mean Temperature Difference. The Engineering Toolbox. Web. 28 July 2014. "Benefits Of Using A Flat Plate Heat Exchanger

  1. COMPARATIVEANALYSIS OF ADVANCED CONTROLLERS IN A HEAT EXCHANGER

    OpenAIRE

    P. Sivakumar

    2013-01-01

    Temperature control of the shell and tube heat exchanger is characteristics of nonlinear, time varying and time lag. Since the temperature control with conventional PID controller cannot meet a wide range of precision temperature control requirement, we design temperature control system of the shell and tube heat exchanger by combining fuzzy and PID control methods in this paper. The simulation and experiments are carried out; making a comparison with conventional PID control showing that fuz...

  2. Experimental and Numerical Comparison of Two Borehole Heat Exchangers

    DEFF Research Database (Denmark)

    Alberdi Pagola, Maria; Poulsen, Søren Erbs

    2014-01-01

    This report outlines key results from a comparative study of two different pipe borehole heat exchanger (BHE) configurations. The work was carried out by VIA University College and in collaboration with GM Plast A/S.......This report outlines key results from a comparative study of two different pipe borehole heat exchanger (BHE) configurations. The work was carried out by VIA University College and in collaboration with GM Plast A/S....

  3. Heat transfer, condensation and fog formation in crossflow plastic heat exchangers

    NARCIS (Netherlands)

    Brouwers, H.J.H.; Geld, van der C.W.M.

    1996-01-01

    In this paper heat transfer of air-water-vapour mixtures in plastic crossflow heat exchangers is studied theoretically and experimentally. First, a model for heat transfer without condensation is derived, resulting in a set of classical differential equations. Subsequently, heat transfer with wall c

  4. A one-dimensional heat transfer model for parallel-plate thermoacoustic heat exchangers

    NARCIS (Netherlands)

    de Jong, Anne; Wijnant, Ysbrand H.; de Boer, Andries

    2014-01-01

    A one-dimensional (1D) laminar oscillating flow heat transfer model is derived and applied to parallel-plate thermoacoustic heat exchangers. The model can be used to estimate the heat transfer from the solid wall to the acoustic medium, which is required for the heat input/output of thermoacoustic

  5. Heat transfer, condensation and fog formation in crossflow plastic heat exchangers

    NARCIS (Netherlands)

    Brouwers, Jos; van der Geld, C.W.M.

    1996-01-01

    In this paper heat transfer of air-water-vapour mixtures in plastic crossflow heat exchangers is studied theoretically and experimentally. First, a model for heat transfer without condensation is derived, resulting in a set of classical differential equations. Subsequently, heat transfer with wall

  6. Brazed aluminum, Plate-fin heat exchangers for OTEC

    Energy Technology Data Exchange (ETDEWEB)

    Foust, H.D.

    1980-12-01

    Brazed aluminum plate-fin heat exchangers have been available for special applications for over thirty years. The performance, compactness, versatility, and low cost of these heat exchangers has been unequaled by other heat exchanger configuration. The application of brazed aluminum has been highly limited because of necessary restrictions for clean non-corrosive atmospheres. Air and gas separation have provided ideal conditions for accepting brazed aluminum and in turn have benefited by the salient features of these plate-fin heat exchangers. In fact, brazed aluminum and cryogenic gas and air separation have become nearly synonymous. Brazed aluminum in its historic form could not be considered for a seawater atmosphere. However, technology presents a new look of significant importance to OTEC in terms of compactness and cost. The significant technological variation made was to include one-piece hollow extensions for the seawater passages. Crevice corrosion sites are thereby entirely eliminated and pitting corrosion attack will be controlled by an integral and sacrificial layer of a zinc-aluminum alloy. This paper on brazed aluminum plate-fin heat exchangers for OTEC will aquaint the reader with the state-of-art and variations suggested to qualify this form of aluminum for seawater use. In order to verify the desirable cost potential for OTEC, Trane teamed with Westinghouse to perform an OTEC system analysis with this heat exchanger. These results are very promising and reported in detail elsewhere.

  7. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa;

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change...... material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the presence of crystallization is studied experimentally. Fluid flow and heat transfer in the PCM module...... are theoretically investigated by Computational Fluid Dynamics (CFD) calculations. The heat transfer rates between the PCM storage and the heating fluid/cooling fluid in the plate heat exchangers are determined. The CFD calculated temperatures are compared to measured temperatures. Based on the studies...

  8. Design of Heat Exchanger Network for VCM Distillation Unit Using Pinch Technology

    Directory of Open Access Journals (Sweden)

    VISHAL G. BOKAN

    2015-06-01

    Full Text Available In process industries, heat exchanger networks represent an important part of the plant structure. The purpose of the networks is to maximize heat recovery, thereby lowering the overall plant costs. In process industries, during operation of any heat exchanger network (HEN, the major aim is to focus on the best performance of the network As in present condition of fuel crises is one of the major problem faced by many country & industrial utility is majorly depend on this. There is technique called process integration which is used for integrate heat within loop so optimize the given process and minimize the heating load and cooling load .In the present study of heat integration on VCM (vinyl chloride monomer distillation unit, Heat exchanger network (HEN is designed by using Aspen energy analyzer V8.0 software. This software implements a methodology for HEN synthesis with the use of pinch technology. Several heat integration networks are designed with different ΔT min and total annualized cost compared to obtain the optimal design. The network with a ΔT min of 90C is the most optimal where the largest energy savings are obtained with the appropriate use of utilities (Save 15.3764% for hot utilities and 47.52% for cold utilities compared with the current plant configuration. Percentage reduction in total operating cost is 18.333%. From calculation Payback Period for new design is 3.15 year. This save could be done through a plant revamp, with the addition of two heat exchangers. This improvement are done in the process associated with this technique are not due to the use of advance unit operation, but to the generation of heat integration scheme. The Pinch Design Method can be employed to give good designs in rapid time and with minimum data.

  9. Assessment of ASME code examinations on regenerative, letdown and residual heat removal heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Gosselin, Stephen R.; Cumblidge, Stephen E.; Anderson, Michael T.; Simonen, Fredric A.; Tinsley, G. A.; Lydell, B.; Doctor, Steven R.

    2005-07-01

    Inservice inspection requirements for pressure retaining welds in the regenerative, letdown, and residual heat removal heat exchangers are prescribed in Section XI Articles IWB and IWC of the ASME Boiler and Pressure Vessel Code. Accordingly, volumetric and/or surface examinations are performed on heat exchanger shell, head, nozzle-to-head, and nozzle-to-shell welds. Inspection difficulties associated with the implementation of these Code-required examinations have forced operating nuclear power plants to seek relief from the U.S. Nuclear Regulatory Commission. The nature of these relief requests are generally concerned with metallurgical, geometry, accessibility, and radiation burden. Over 60% of licensee requests to the NRC identify significant radiation exposure burden as the principle reason for relief from the ASME Code examinations on regenerative heat exchangers. For the residual heat removal heat exchangers, 90% of the relief requests are associated with geometry and accessibility concerns. Pacific Northwest National Laboratory was funded by the NRC Office of Nuclear Regulatory Research to review current practice with regard to volumetric and/or surface examinations of shell welds of letdown heat exchangers regenerative heat exchangers and residual (decay) heat removal heat exchangers Design, operating, common preventative maintenance practices, and potential degradation mechanisms are reviewed. A detailed survey of domestic and international PWR-specific operating experience was performed to identify pressure boundary failures (or lack of failures) in each heat exchanger type and NSSS design. The service data survey was based on the PIPExp® database and covers PWR plants worldwide for the period 1970-2004. Finally a risk assessment of the current ASME Code inspection requirements for residual heat removal, letdown, and regenerative heat exchangers is performed. The results are then reviewed to discuss the examinations relative to plant safety and

  10. Heat exchanger selection and design analyses for metal hydride heat pump systems

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Voskuilen, Tyler G.; Waters, Essene L.

    2016-01-01

    This study presents a design analysis for the development of highly efficient heat exchangers within stationary metal hydride heat pumps. The design constraints and selected performance criteria are applied to three representative heat exchangers. The proposed thermal model can be applied to select...... the most efficient heat exchanger design and provides outcomes generally valid in a pre-design stage. Heat transfer effectiveness is the principal performance parameter guiding the selection analysis, the results of which appear to be mildly (up to 13%) affected by the specific Nusselt correlation used....... The thermo-physical properties of the heat transfer medium and geometrical parameters are varied in the sensitivity analysis, suggesting that the length of independent tubes is the physical parameter that influences the performance of the heat exchangers the most. The practical operative regions for each...

  11. Flow mechanism and heat transfer enhancement in longitudinal-flow tube bundle of shell-and-tube heat exchanger

    Institute of Scientific and Technical Information of China (English)

    LIU Wei; LIU ZhiChun; WANG YingShuang; HUANG SuYi

    2009-01-01

    ormer is superior to that of the latter.Compared with rod baffle heat exchanger,heat transfer coefficient of the heat exchanger under investigation is higher under same pressure drop,especially under the high Reynolds numbers.

  12. Demonstration of leapfrogging for implementing nonlinear model predictive control on a heat exchanger.

    Science.gov (United States)

    Sridhar, Upasana Manimegalai; Govindarajan, Anand; Rhinehart, R Russell

    2016-01-01

    This work reveals the applicability of a relatively new optimization technique, Leapfrogging, for both nonlinear regression modeling and a methodology for nonlinear model-predictive control. Both are relatively simple, yet effective. The application on a nonlinear, pilot-scale, shell-and-tube heat exchanger reveals practicability of the techniques.

  13. NGNP/HTE full-power operation at reduced high-temperature heat exchanger temperatures.

    Energy Technology Data Exchange (ETDEWEB)

    VIlim, R.; Nuclear Engineering Division

    2009-03-12

    Operation of the Next Generation Nuclear Plant (NGNP) with reduced reactor outlet temperature at full power was investigated for the High Temperature Electrolysis (HTE) hydrogen-production application. The foremost challenge for operation at design temperature is achieving an acceptably long service life for heat exchangers. In both the Intermediate Heat Exchanger (IHX) and the Process Heat Exchanger (PHX) (referred to collectively as high temperature heat exchangers) a pressure differential of several MPa exists with temperatures at or above 850 C. Thermal creep of the heat exchanger channel wall may severely limit heat exchanger life depending on the alloy selected. This report investigates plant performance with IHX temperatures reduced by lowering reactor outlet temperature. The objective is to lower the temperature in heat transfer channels to the point where existing materials can meet the 40 year lifetime needed for this component. A conservative estimate for this temperature is believed to be about 700 C. The reactor outlet temperature was reduced from 850 C to 700 C while maintaining reactor power at 600 MWt and high pressure compressor outlet at 7 MPa. We included a previously reported design option for reducing temperature at the PHX. Heat exchanger lengths were adjusted to reflect the change in performance resulting from coolant property changes and from resizing related to operating-point change. Turbomachine parameters were also optimized for the new operating condition. An integrated optimization of the complete system including heat transfer equipment was not performed. It is estimated, however, that by performing a pinch analysis the combined plant efficiency can be increased from 35.5 percent obtained in this report to a value between 38.5 and 40.1 percent. Then after normalizing for a more than three percent decrease in commodities inventory compared to the reference plant, the commodities-normalized efficiency lies between 40.0 and 41.3. This

  14. Optimal Heating Strategies for a Convection Oven

    NARCIS (Netherlands)

    Stigter, J.D.; Scheerlinck, N.; Nicolai, B.M.; Impe, van J.F.

    2001-01-01

    In this study classical control theory is applied to a heat conduction model with convective boundary conditions. Optimal heating strategies are obtained through solution of an associated algebraic Riccati equation for a finite horizon linear quadratic regulator (LQR). The large dimensional system

  15. Analysis of Short Time Period of Operation of Horizontal Ground Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Salsuwanda Selamat

    2015-07-01

    Full Text Available Ground source heat pump (GSHP systems have been proven to have higher efficiency compared to conventional air source heat pump systems for space heating and cooling applications. While vertical ground heat exchangers (GHE are favorable in GSHP installation, this type of configuration requires higher capital costs as opposed to horizontal configuration. Numerical simulation has been used to accurately predict the thermal performance of GHE. In this paper, numerical analysis of thermal performance for slinky horizontal GHE loops in different orientations and operation modes is discussed. It was found that the loop orientation is not so important due to the little effect it has on thermal performance. While the mean heat exchange rate of copper loop increases 48% compared to HDPE loop, the analysis supports the common claim that heat exchange rate is predominantly limited by the thermal conductivity of the ground. With the same amount of circulation work, the mean heat exchange rate increases by 83%–162% when operated in parallel loops operations. The performance in these operations can be further optimized to 10%–14% increase when spacing between adjacent loops was provided. The spacing helps to minimize interference of heat flow that would penalize the overall thermal performance.

  16. Analysis of thermosyphon heat exchangers for use in solar domestic hot water heating systems

    Science.gov (United States)

    Dahl, Scott David

    1998-11-01

    A recent innovation in the solar industry is the use of thermosyphon heat exchangers. Determining the performance of these systems requires knowledge of how thermosyphon flow rate and heat exchanger performance vary with operating conditions. This study demonstrates that several thermosyphon heat exchanger designs operate in the laminar mixed convection regime. Empirical heat transfer and pressure drop correlations are obtained for three tube-in-shell heat exchangers (four, seven, and nine tube). Thermosyphon flow is on the shell side. Correlations are obtained with uniform heat flux on the tube walls and with a mixture of glycol and water circulating inside the tubes. Ranges of Reynolds, Prandtl, and Grashof numbers are 50 to 1800, 2.5 and 6.0, and 4×105 to 1×108, respectively. Nusselt number correlations are presented in a form that combines the contributions of forced and natural convection, Nu4Mixed=Nu4Forced+Nu4Natural. The Nusselt number is influenced by natural convection when the term Raq0.25/(Re0.5Pr0.33) is greater than unity. Pressure drop through these three designs is not significantly affected by mixed convection because most pressure drop losses are at the heat exchanger inlet and outlet. A comparison and discussion of the performance of several other heat exchanger designs (tube-in-shell and coil-in- shell designs) are presented. Generally, the coil-in- shell heat exchangers perform better than the tube-in- shell heat exchangers. Data from all heat exchanger designs is used to develop a new one-dimensional model for thermosyphon heat exchangers in solar water heating systems. The model requires two empirically determined relationships, pressure drop as a function of water mass flow rate and the overall heat transfer coefficient-area product (UA) as a function of Reynolds, Prandtl, and Grashof number. A testing protocol is presented that describes the procedure to obtain the data for the correlations. Two new TRNSYS component models are presented

  17. In - line determination of heat transfer coefficients in a plate heat exchanger

    Science.gov (United States)

    Sotelo, S. Silva; Domínguez, R. J. Romero

    This paper shows an in - line determination of heat transfer coefficients in a plate heat exchanger. Water and aqueous working solution of lithium bromide + ethylene glycol are considered. Heat transfer coefficients are calculated for both fluids. "Type T" thermocouples were used for monitoring the wall temperature in a plate heat exchanger, which is one of the main components in an absorption system. Commercial software Agilent HP Vee Pro 7.5 was used for monitoring the temperatures and for the determination of the heat transfer coefficients. There are not previous works for heat transfer coefficients for the working solution used in this work.

  18. Sprinkled Heat Exchangers in Evaporation Mode

    Directory of Open Access Journals (Sweden)

    Pospisil J.

    2013-04-01

    Full Text Available The paper presents research on the heat transfer at sprinkled tube bundles situated in a test chamber at atmospheric pressure and low-pressure. Dynamic effects of physical quantities influencing the heat transfer coefficient during boiling are examined experimentally. Experimental results were achieved by means of balance measuring using thermocouple probes and by analysis of thermal diagrams created during operation periods.

  19. CFD as a Design Tool for a Concentric Heat Exchanger

    NARCIS (Netherlands)

    Oosterhuis, J.P.; Bühler, S.; wilcox, D; Meer, van der T.H.

    2012-01-01

    A concentric gas-to-gas heat exchanger is designed for application as a recuperator in the domestic boiler industry. The recuperator recovers heat from the exhaust gases of a combustion process to preheat the ingoing gaseous fuel mixture resulting in increased fuel efficiency. This applied study sho

  20. A structured approach to heat exchanger network retrofit design

    NARCIS (Netherlands)

    Van Reisen, J.L.B.

    2008-01-01

    Process plants have high energy consumption. Much energy can be saved by a proper design of the heat exchanger network, which contains the main heat transferring equipment of the plant. Existing plants can often be made more energy-efficient by a retrofit: the (physical) modification of the equipmen

  1. Combined mass and heat exchange network synthesis based on stage-wise superstructure model☆

    Institute of Scientific and Technical Information of China (English)

    Linlin Liu; Jian Du; Fenglin Yang

    2015-01-01

    Integrating multiple systems into one has become an important trend in Process Systems Engineering research field since there is strong demand from the modern industries. In this study, a stage-wise superstructure-based method is proposed to synthesize a combined mass and heat exchange network (CM&HEN) which has two parts as the mass exchange network (MEN) and heat exchange network (HEN) involved. To express the pos-sible heat exchange requirements resulted from mass exchange operations, a so cal ed“indistinct HEN super-structure (IHS)”, which can contain the all potential matches between streams, is constructed at first. Then, a non-linear programming (NLP) mathematical model is established for the simultaneous synthesis and optimiza-tion of networks. Therein, the interaction between mass exchange and heat exchange is modeling formulated. The NLP model has later been examined using an example from literature, and the effectiveness of the proposed method has been demonstrated with the results.

  2. 三角形纵向涡在管翅式换热器的应用及优化%Application and Optimization of Triangular Longitudinal Vortex in Fin and Tube Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    王成刚; 高兴; 刘俊; 刘慧

    2014-01-01

    The longitudinal vortex can increase heat transfer coefficient of the fin and tube heat exchanger, and the flow resistance increases slightly. In this paper, numerical simulation on the fin and tube heat exchanger with 4 kinds of different structure fins (plain fin,H3/6,H4/6 and H5/6) was carried out. The results show that the heat transfer coefficient of the fin and tube heat exchanger with the longitudinal vortex generator is obviously increased, and the highest increase reaches 49%, at the same time resistance coefficient J also has obvious increase. The resistance factor of the fin and tube heat exchanger with the longitudinal vortex H5/6 fin has minimal increase;it is almost the same with that with plain fin. Finally, it’s pointed out that the fin and tube heat exchanger with H5/6 type longitudinal vortex fin has the best comprehensive effect.%纵向涡能够在增加管翅式换热器换热系数,同时较小幅度地增加其流动阻力。本文通过对4种结构的翅片(未进行任何处理的平翅片,结构为高为H3/6、H4/6、H5/6且攻角为30°长高比为2)进行数值模拟。结果显示安装纵向涡发生器的翅片的传热系数明显增强,且最高增加49%。在换热系数增加的同时阻力系数j也有明显的增加。其中安装纵向涡H5/6型翅片的阻力因子增加最小与平翅片几乎相同。最后本文通过对综合评价因子j/f的比较得知安装H5/6型纵向涡翅片具有最好的综合效果。

  3. Heat Transfer Analysis of Passive Residual Heat Removal Heat Exchanger under Natural Convection Condition in Tank

    Directory of Open Access Journals (Sweden)

    Qiming Men

    2014-01-01

    Full Text Available Aiming at the heat transfer calculation of the Passive Residual Heat Removal Heat Exchanger (PRHR HX, experiments on the heat transfer of C-shaped tube immerged in a water tank were performed. Comparisons of different correlation in literatures with the experimental data were carried out. It can be concluded that the Dittus-Boelter correlation provides a best-estimate fit with the experimental results. The average error is about 0.35%. For the tube outside, the McAdams correlations for both horizontal and vertical regions are best-estimated. The average errors are about 0.55% for horizontal region and about 3.28% for vertical region. The tank mixing characteristics were also investigated in present work. It can be concluded that the tank fluid rose gradually which leads to a thermal stratification phenomenon.

  4. Analysis of heat exchanger network for temperature fluctuation

    Directory of Open Access Journals (Sweden)

    Jin Zunlong

    2015-09-01

    Full Text Available Subject to temperature disturbance, exchangers in heat exchanger network will interact. It is necessary to evaluate the degree of temperature fluctuation in the network. There is inherently linear relationship between output and inlet temperatures of heat exchanger network. Based on this, the concept of temperature-change sensitivity coefficient was put forward. Quantitative influence of temperature fluctuation in the network was carried out in order to examine transmission character of temperature fluctuation in the system. And the information was obtained for improving the design quality of heat exchanger network. Favorable results were obtained by the introduced method compared with the experimental results. These results will assist engineers to distinguish primary and secondary influencing factors, which can be used in observing and controlling influencing factors accurately.

  5. Compact interior heat exchangers for CO{sub 2} mobile heat pumping systems

    Energy Technology Data Exchange (ETDEWEB)

    Hafner, Armin

    2003-07-01

    The natural refrigerant carbon dioxide (CO{sub 2}) offers new possibilities for design of flexible, efficient and environmentally safe mobile heat pumping systems. As high-efficient car engines with less waste heat are developed, extra heating of the passenger compartment is needed in the cold season. A reversible transcritical CO{sub 2} system with gliding temperature heat rejection can give high air delivery temperature which results in rapid heating of the passenger compartment and rapid defogging or defrosting of windows. When operated in cooling mode, the efficiency of transcritical CO{sub 2} systems is higher compared to common (HFC) air conditioning systems, at most dominant operating conditions. Several issues were identified for the design of compact interior heat exchangers for automotive reversible CO{sub 2} heat pumping systems. Among theses issues are: (1) Refrigerant flow distribution, (2) Heat exchanger fluid flow circuiting, (3) Air temperature uniformity downstream of the heat exchanger, (4) Minimization of temperature approach, (5) Windshield flash fogging due to retained water inside the heat exchanger, (6) Internal beat conduction in heating mode operation, and (7) Refrigerant side pressure drop In order to provide a basis for understanding these issues, the author developed a calculation model and set up a test facility and investigated different prototype heat exchangers experimentally.

  6. Laminar fluid flow and heat transfer in a fin-tube heat exchanger with vortex generators

    Energy Technology Data Exchange (ETDEWEB)

    Yanagihara, J.I.; Rodriques, R. Jr. [Polytechnic School of Univ. of Sao Paolo, Sao Paolo (Brazil). Dept. of Mechanical Engineering

    1996-12-31

    Development of heat transfer enhancement techniques for fin-tube heat exchangers has great importance in industry. In recent years, heat transfer augmentation by vortex generators has been considered for use in plate fin-tube heat exchangers. The present work describes a numerical investigation about the influence of delta winglet pairs of vortex generators on the flow structure and heat transfer of a plate fin-tube channel. The Navier-Stokes and Energy equations are solved by the finite volume method using a boundary-fitted coordinate system. The influence of vortex generators parameters such as position, angle of attack and aspect ratio were investigated. Local and global influences of vortex generators in heat transfer and flow losses were analyzed by comparison with a model using smooth fin. The results indicate great advantages of this type of geometry for application in plate fin-tube heat exchangers, in terms of large heat transfer enhancement and small pressure loss penalty. (author)

  7. Finned tubes for heat exchangers: Characterization and performance simulation

    Energy Technology Data Exchange (ETDEWEB)

    Armand, J.-L.; Molle, N. (Centre Tecnique des Industries Aerauliques et Thermiques (CETIAT), 75 Paris (France))

    1992-06-01

    Relevant to air conditioning applications, the state-of-the-art of finned tube heat exchanger design is reviewed. The review covers the key design, performance and operation characteristics, as well as, principal heat transfer correlations for exchangers adopting 'dry' (without condensation) and 'wet' operation. External side heat transfer and pressure drop calculation methods are established for the characterization of external surfaces. For internal surfaces, correlations are given for two-phase flow and pressure drop. Reference is made to the NTU and CANUT simulation codes for the determination of optimum finned tube geometries for standard and particular operating conditions.

  8. An Investigation of the Characteristics of Regenerative Heat Exchangers

    Science.gov (United States)

    1996-06-01

    regenerator , a Stirling refrigeration cycle will be examined. The Stirling Cycle. This section describes the basic elements of a Stirling ...The dominant energy transfer process in a Stirling cycle is the exchange of heat between the working gas and the regenerator . The heat transferred to...P 4 i V ( s REGENERATOR EXPANSION SPACE COMPRESSION SPACE (2) T (4) Figure 2. Ideal Stirling Thermodynamic Cycle (Walker, 1983:45) 1990:236). The heat

  9. Performance of parallel flow HeII heat exchangers

    Science.gov (United States)

    Huang, Y.; Chang, Y.; Witt, R. J.; Van Sciver, S. W.

    Previous studies of HeII heat exchangers have focused on tube-in-shell designs. The present paper examines the properties of a parallel flow HeII heat exchanger formed from two 254 mm lengths of copper channel having nominal rectangular dimensions 2 mm × 4 mm. Heaters positioned at the inlets and outlets of both channels permit the simulation of a variety of physically plausible boundary conditions. An iterative numerical method, based on one-dimensional energy balances in each channel with coupling through a heat transfer term, is presented and agrees well with the experimental results. As with tube-in-shell designs, parallel flow HeII heat exchangers may exhibit unusual temperature profiles.

  10. R&D on Resistive Heat Exchangers for HTS High Rated Current Leads%R&D on Resistive Heat Exchangers for HTS High Rated Current Leads

    Institute of Scientific and Technical Information of China (English)

    毕延芳

    2011-01-01

    The HTS current leads of superconducting magnets for large scale fusion devices and high energy particle colliders can reduce the power consumption for cooling by 2/3 compared with conventional leads. The resistive sections of high-rated current leads are usually made of a heat exchanger cooled by gas flow. The supply of the cooling mass flow incurs more than 90% of the cooling cost for the HTS leads. The mass flow rate requirement depends not only on the length and material of the resistive heat exchanger, but also on the heat transfer coefficient and HEX surface, the joint resistance at the cold end of a sheet-stack HEX with a larger specific presented in the paper. The test results of efficiency can be achieved. and its cooling approach. The design and operation surface and a much smaller hydraulic diameter are an HTS lead optimized for 8 kA show that a 98.4%

  11. Optimized ground coupled heat pump mechanical package

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.A.

    1984-01-01

    The system which was optimized was a horizontal earth coil in a given house in the Pittsburgh area. The types of components used in the heat pump are essentially conventional. The method of this study is derived from one used to optimize an air-source heat pump for operation at standard steady state conditions. A computer model, created at Oak Ridge National Laboratory (ORNL), is used to predict heat pump performance for specified configuration and operating conditions. A predetermined set of design parameters is automatically altered by a constrained minimization program (a Numerical Algorithms Group library routine hereafter referred to as the optimizer) to find the combination for which the highest COP is predicted by the heat pump model. In the present study, the set of parameters to be varied include some pertaining to the ground coil as well as some pertaining to the heat pump. The optimizer, in this case, pursues a minimum life cycle cost which is calculated using the heat pump model, a ground coil model (called FTECM for Fast Transient Earth Coil model), and a parameterized cost model. The flow chart shows how the optimizer interacts with these programs to minimize life cycle cost.

  12. Boiling heat transfer of refrigerant R-21 in upward flow in plate-fin heat exchanger

    Science.gov (United States)

    Kuznetsov, V. V.; Shamirzaev, A. S.

    2015-11-01

    The article presents the results of experimental investigation of boiling heat transfer of refrigerant R-21 in upward flow in a vertical plate-fin heat exchanger with transverse size of the channels that is smaller than the capillary constant. The heat transfer coefficients obtained in ranges of small mass velocities and low heat fluxes, which are typical of the industry, have been poorly studied yet. The characteristic patterns of the upward liquid-vapor flow in the heat exchanger channels and the regions of their existence are detected. The obtained data show a weak dependence of heat transfer coefficient on equilibrium vapor quality, mass flow rate, and heat flux density and do not correspond to calculations by the known heat transfer models. A possible reason for this behavior is a decisive influence of evaporation of thin liquid films on the heat transfer at low heat flux.

  13. Numerical topology optimization of heat sinks

    OpenAIRE

    Van Oevelen, Tijs; Baelmans, Martine

    2014-01-01

    The availability of flexible production techniques challenges their full exploitation during thermo-hydraulic design of micro heat sinks. In this context, a systematic approach capable to take advantage of the practically unlimited design freedom is highly desirable. Therefore, we propose to use topology optimization, a numerical design optimization method well-established in structural mechanics problems. In this paper, the fundamentals of topology optimization, and its application in thermo...

  14. Flow mechanism and heat transfer enhancement in longitudinal-flow tube bundle of shell-and-tube heat exchanger

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The flow disturbance and heat transfer mechanism in the tube bundle of rod baffle shell-and-tube heat exchanger were analyzed, on the basis of which and combined with the concept of heat transfer enhancement in the core flow, a new type of shell-and-tube heat exchanger with combination of rod and van type spoiler was designed. Corresponding mathematical and physical models on the shell side about the new type heat exchanger were established, and fluid flow and heat transfer characteristics were numerically analyzed. The simulation results showed that heat transfer coefficient of the new type of heat exchanger approximated to that of rod baffle heat exchanger, but flow pressure drop was much less than the latter, indicating that comprehensive performance of the former is superior to that of the latter. Compared with rod baffle heat exchanger, heat transfer coefficient of the heat exchanger under investigation is higher under same pressure drop, especially under the high Reynolds numbers.

  15. Heat exchangers selection, rating, and thermal design

    CERN Document Server

    Kakaç, Sadik; Pramuanjaroenkij, Anchasa

    2012-01-01

    Praise for the Bestselling Second EditionThe first edition of this work gathered in one place the essence of important information formerly scattered throughout the literature. The second edition adds the following new information: introductory material on heat transfer enhancement; an application of the Bell-Delaware method; new correlation for calculating heat transfer and friction coefficients for chevron-type plates; revision of many of the solved examples and the addition of several new ones.-MEMagazine

  16. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-04-01

    The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. The intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding.

  17. Intensification of heat and mass transfer by ultrasound: application to heat exchangers and membrane separation processes.

    Science.gov (United States)

    Gondrexon, N; Cheze, L; Jin, Y; Legay, M; Tissot, Q; Hengl, N; Baup, S; Boldo, P; Pignon, F; Talansier, E

    2015-07-01

    This paper aims to illustrate the interest of ultrasound technology as an efficient technique for both heat and mass transfer intensification. It is demonstrated that the use of ultrasound results in an increase of heat exchanger performances and in a possible fouling monitoring in heat exchangers. Mass transfer intensification was observed in the case of cross-flow ultrafiltration. It is shown that the enhancement of the membrane separation process strongly depends on the physico-chemical properties of the filtered suspensions.

  18. Heat recovery from Diesel exhausts by means of a fluidized bed heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Carlomagno, G.M.; Festa, R.; Massimilla, L.

    1983-01-01

    A fluidized bed heat exchanger, equipped with a specially designed manifold gas distributor, is conveniently used to recover heat from exhausts of a 60 kW Diesel engine. The sensitivity of the bed to tube heat transfer coefficient to soot fouling and the sensitivity of the exchanger efficiency to variations of such coefficients are analyzed. Procedures for in-operation tube defouling are described.

  19. Aplicación del Método de la Colonia de Hormigas Mixto a la optimización de intercambiadores de calor de tubo y coraza//Application of the Mixed Ant Colony Method to the optimization of tube and shell heat exchangers

    Directory of Open Access Journals (Sweden)

    Maida Bárbara Reyes‐Rodríguez

    2014-05-01

    Full Text Available Los procesos de transferencia de calor sonuno de los problemas más importantes a resolver en el campo de la Ingeniería. Entre los equipos más usados en la industria para realizar la transferencia de calor están los intercambiadores de calor de tubo y coraza. En el presente trabajo se desarrolla el procedimiento para la optimización del diseño de estos equipos utilizando el método de Kern y aplicando el algoritmo de la colonia de hormigas. Se aplica el mismo a tres ejemplos concretos y los resultados obtenidos se comparan con los obtenidos aplicando otros métodos de la inteligencia artificial. Se optimizan los principales parámetros geométricos de los intercambiadores de calor de tubo y coraza para lograr un menor costo de los mismos. Se demuestra la eficacia del nuevo procedimiento MACO (Mixed Ant Colony Optimization, en el proceso de optimización desde el punto de vista económico utilizando diferentes casos de estudios.Palabras claves: intercambiadores de calor, colonia de hormigas, método de Kern.______________________________________________________________________________AbstractHeat transfer processes are one of the most important problems to be solved in the field of Engineering. Among the most widely used equipment for heat transfer in the industry are the shell and tube heat exchangers. This paper develops the procedure for optimizing the design of shell and tube heat exchangers using the method of Kern and applying the ant colony algorithm. The procedure has been applied to three specific examples and the results obtained are compared with those obtained by applying other methods of artificial intelligence. The main geometric parameters of shell and tube heat exchangers are optimized, to achieve a lower cost of the exchanger. The efficacy of the new procedure MACO (Mixed Ant Colony Optimization for the optimization process from economically point of view was demonstrated, using different case studies.Key words: heat

  20. Structure Optimization for Heat Exchanger Baffle Based on Computational Fluid Dynamics Simulation of Thermal-Fluid-Structure Coupling%基于计算流体力学热流固耦合仿真的换热器折流板结构优化

    Institute of Scientific and Technical Information of China (English)

    张仂; 谷芳

    2012-01-01

    采用多物理场耦合方法,建立了管壳式换热器的计算流体力学(CFD)热流固耦合仿真分析模型,对20种不同折流板结构参数的管壳式换热器进行了流动与传热的数值模拟.CFD仿真计算结果显示,换热器的折流板间距和折流板缺口高度对流动和传热的影响相互关联,不能进行单目标优化设计.以JF因子作为换热器综合性能的评价准则,对管壳式换热器的折流板间距和折流板缺口高度进行了结构优化设计,提出在换热器内径(d)200 mm、换热管长1140 mm、并流条件下,该换热器的最佳折流板间距为80 mm(折流板数目为10),最佳折流板缺口高度为0.3d(即60 mm).%A thermal-fluid-structure coupling simulation model for shell-and-tube heat exchangers was established based on computational fluid dynamics(CFD) by a multi-physical field coupling method. The flow and heat transfer in 20 different types of shell-and-tube heat exchangers with different baffle structural parameters were simulated by the model. The CFD simulation results showed that the effects of the baffle spacing and baffle gap height on the flow and heat transfer interconnected, which showed that the single-objective optimization could not be achieved. With JF factors as the evaluation criteria of the heat exchanger performances, the baffle spacings and baffle gap heights in the shell-and-tube heat exchangers were optimized. It was put forward that under the conditions of parallel flow, inside diameter of the heat exchanger(d)200 mm and heat exchange tube length 1 140 mm, the baffle space and baffle gap height were 80 mm(the baffle number 10) and 0.3d(60 mm), respectively.

  1. Geothermal heat exchanger with coaxial flow of fluids

    Directory of Open Access Journals (Sweden)

    Pejić Dragan M.

    2005-01-01

    Full Text Available The paper deals with a heat exchanger with coaxial flow. Two coaxial pipes of the secondary part were placed directly into a geothermal boring in such a way that geothermal water flows around the outer pipe. Starting from the energy balance of the exchanger formed in this way and the assumption of a study-state operating regime, a mathematical model was formulated. On the basis of the model, the secondary circle output temperature was determined as a function of the exchanger geometry, the coefficient of heat passing through the heat exchange areas, the average mass isobaric specific heats of fluid and mass flows. The input temperature of the exchanger secondary circle and the temperature of the geothermal water at the exit of the boring were taken as known values. Also, an analysis of changes in certain factors influencing the secondary water temperature was carried out. The parameters (flow temperature of the deep boring B-4 in Sijarinska Spa, Serbia were used. The theoretical results obtained indicate the great potential of this boring and the possible application of such an exchanger.

  2. Analysis of radiative heat transfer impact in cross-flow tube and fin heat exchangers

    Science.gov (United States)

    Hanuszkiewicz-Drapała, Małgorzata; Bury, Tomasz; Widziewicz, Katarzyna

    2016-03-01

    A cross-flow, tube and fin heat exchanger of the water - air type is the subject of the analysis. The analysis had experimental and computational form and was aimed for evaluation of radiative heat transfer impact on the heat exchanger performance. The main element of the test facility was an enlarged recurrent segment of the heat exchanger under consideration. The main results of measurements are heat transfer rates, as well as temperature distributions on the surface of the first fin obtained by using the infrared camera. The experimental results have been next compared to computational ones coming from a numerical model of the test station. The model has been elaborated using computational fluid dynamics software. The computations have been accomplished for two cases: without radiative heat transfer and taking this phenomenon into account. Evaluation of the radiative heat transfer impact in considered system has been done by comparing all the received results.

  3. Numerical evaluation of plate heat exchanger performance in geothermal district heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, T. [Iceland Univ., Reykjavik (Iceland)

    1996-12-31

    This paper describes the performance of plate heat exchangers in residential water radiator heating systems receiving their heat from geothermal resources. Radiator theory is reviewed and determination of annual hot water requirements for space heating is discussed. Performance evaluation is made of plate heat exchangers and results obtained by means of two equations commonly used for this purpose, the Sieder-Tate and the Dittus-Boelter equations, compared to results obtained with a simplified equation where heat transfer in the heat exchanger is assumed to depend only on the fluid mass flow on both sides. It is found that for prevailing temperature ranges in Icelandic geothermal systems the mass pow approximation gives results very close to those determined by the more complicated conventional equations. (UK)

  4. Analysis of radiative heat transfer impact in cross-flow tube and fin heat exchangers

    Directory of Open Access Journals (Sweden)

    Hanuszkiewicz-Drapała Małgorzata

    2016-03-01

    Full Text Available A cross-flow, tube and fin heat exchanger of the water – air type is the subject of the analysis. The analysis had experimental and computational form and was aimed for evaluation of radiative heat transfer impact on the heat exchanger performance. The main element of the test facility was an enlarged recurrent segment of the heat exchanger under consideration. The main results of measurements are heat transfer rates, as well as temperature distributions on the surface of the first fin obtained by using the infrared camera. The experimental results have been next compared to computational ones coming from a numerical model of the test station. The model has been elaborated using computational fluid dynamics software. The computations have been accomplished for two cases: without radiative heat transfer and taking this phenomenon into account. Evaluation of the radiative heat transfer impact in considered system has been done by comparing all the received results.

  5. CFD analysis of the plate heat exchanger - Mathematical modelling of mass and heat transfer in serial connection with tubular heat exchanger

    Science.gov (United States)

    Bojko, Marian; Kocich, Radim

    2016-06-01

    Application of numerical simulations based on the CFD calculation when the mass and heat transfer between the fluid flows is essential component of thermal calculation. In this article the mathematical model of the heat exchanger is defined, which is subsequently applied to the plate heat exchanger, which is connected in series with the other heat exchanger (tubular heat exchanger). The present contribution deals with the possibility to use the waste heat of the flue gas produced by small micro turbine. Inlet boundary conditions to the mathematical model of the plate heat exchanger are obtained from the results of numerical simulation of the tubular heat exchanger. Required parameters such for example inlet temperature was evaluated from temperature field, which was subsequently imported to the inlet boundary condition to the simulation of plate heat exchanger. From the results of 3D numerical simulations are evaluated basic flow variables including the evaluation of dimensionless parameters such as Colburn j-factor and friction ft factor. Numerical simulation is realized by software ANSYS Fluent15.0.

  6. Temperatures and Heat Flows in a Soil Enclosing a Slinky Horizontal Heat Exchanger

    OpenAIRE

    Pavel Neuberger; Radomír Adamovský; Michaela Šeďová

    2014-01-01

    Temperature changes and heat flows in soils that host “slinky”-type horizontal heat exchangers are complex, but need to be understood if robust quantification of the thermal energy available to a ground-source heat pump is to be achieved. Of particular interest is the capacity of the thermal energy content of the soil to regenerate when the heat exchangers are not operating. Analysis of specific heat flows and the specific thermal energy regime within the soil, including that captured by the ...

  7. A SIMPLIFIED PREDICTIVE CONTROL FOR A SHELL AND TUBE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    S.RAJASEKARAN,

    2010-12-01

    Full Text Available In this paper a simplified predictive control design is applied for the controlling a temperature of a fluid stream using the shell and tube heat exchanger. The predictive control design based on Dynamic Matrix Control (DMC involves the complicated inversion computation for higher dimensional matrix. Using DMC for controlling a temperature of the shell and tube heat exchanger, there is still a need for optimization of conversation of energy. The simplified predictive control is based on DMC, which reduces the computational complexity by exploring its internal mechanism. Finally the simplified Predictive Control is applied to shell and tube heat exchanger and the results of this control algorithm compared with the conventional PID controller and DMC based PID Controllers.

  8. Inverse heat transfer problem in digital temperature control in plate fin and tube heat exchangers

    Science.gov (United States)

    Taler, Dawid; Sury, Adam

    2011-12-01

    The aim of the paper is a steady-state inverse heat transfer problem for plate-fin and tube heat exchangers. The objective of the process control is to adjust the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a preset value. Two control techniques were developed. The first is based on the presented mathematical model of the heat exchanger while the second is a digital proportional-integral-derivative (PID) control. The first procedure is very stable. The digital PID controller becomes unstable if the water volumetric flow rate changes significantly. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments showed that the PID controller works also well but becomes frequently unstable.

  9. Experimental investigation on heat transfer analysis of conical coil heat exchanger with 90° cone angle

    Science.gov (United States)

    Purandare, Pramod S.; Lele, Mandar M.; Gupta, Raj Kumar

    2015-03-01

    In the present study, an experimental investigation on thermal performance of the conical coil heat exchanger with 90° conical coil heat exchanger is reported. Three different conical coil heat exchangers of same mean coil diameter (Dm = 200 mm) with different tube diameters ( di = 8, 10, 12.5 mm) are analyzed under steady state condition. The analysis is carried out for the tube side hot fluid flow range of 10-100 lph ( Re = 500-5,000), while the shell side flow range of 30-90 lph. The data available from experimentation leads to evaluate heat transfer coefficients for inside and outside the tube of the conical coil heat exchanger by Wilsons plot method. The calculations are further extended to estimate Nusselt Number ( Nu) and effectiveness. The empirical correlations are proposed for predicting Nu and the outlet temperatures of hot and cold fluids. The predicted empirical correlations show reasonable agreement with the experimental results within the given range of parameters.

  10. Efficiency of Vertical Geothermal Heat Exchangers in the Ground Source Heat Pump System

    Institute of Scientific and Technical Information of China (English)

    Heyi Zeng; Nairen Diao; Zhaohong Fang

    2003-01-01

    Taking the fluid temperature distribution along the borehole depth into account, a new quasi-three-dimensional model for vertical ground heat exchangers has been established, which provides a better understanding of the heat transfer processes in the geothermal heat exchangers. On this basis the efficiency of the borehole has been defined and its analytical expression derived. Comparison with the previous two-dimensional model shows that the quasi-three-dimensional model is more rational and more accurate to depict the practical feature of the conduction of geothermal heat exchanger, and the efficiency notion can be easily used to determine the inlet and outlet temperature of the circulating fluid inside the heat exchanger.

  11. Numerical Study of Condensation Heat Exchanger Design in a Saturated Pool: Correlation Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Joon [Kookmin University, Seoul (Korea, Republic of); Lee, Tae Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    Generally the condensation heat exchanger has higher heat transfer coefficient compared to the single phase heat exchanger, so has been widely applied to the cooling systems of fissile power plant. Recently vertical or horizontal type condensation heat exchangers are being studied for the application to secondary passive cooling system of nuclear plants. To design vertical condensation heat exchanger in a saturated water pool, a thermal sizing program of condensation heat exchanger, TSCON(Thermal Sizing of CONdenser) was developed. In this study, condensing heat transfer correlation of TSCON is evaluated with the existing experimental data set to design condensation heat exchanger without noncondensable gas effect (pure steam condensation)

  12. Development of User-Friendly Software to Design Dairy Heat Exchanger and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    DipankarMandal

    2015-02-01

    Full Text Available The paper proposes a calculation algorithm and development of a software in Visual Basic(Visual Studio 2012 Express Desktop used in heat transfer studies when different heat exchangers are involved (e.g. Helical Type Triple Tube Heat Exchanger , Plate Type Heat Exchanger.It includes the easy calculation of heat transfer coefficient and followed by the design and simulation of heat exchanger design parameter by inputting general known parameters of a heat exchanger into the developed software—-―DAIRY –HE ―. A parametric study is conducted using the software interface to determine the length of tubes or dimensions of heat exchanger.

  13. Thermal stress in SiC element used in heat exchanger

    Institute of Scientific and Technical Information of China (English)

    LI He-song; MEI Chi

    2005-01-01

    An especial snake SiC pipe was designed for collecting losing heat from furnaces. The three-dimensions thermal, fluid and thermal stress coupled field of heat exchanger was analyzed by using the commercial engineering computer package ANSYS. The structural and operational parameters of heat exchanger, the junction between standpipe and snake pipe, the diameter of snake pipe, ratio of thickness to diameter of pipe, velocity of inlet air were optimized for thermal stress. The computed results show that the large thermal stress exits in the SiC, and the stand pipe should be ellipse for the least thermal stress; the optimal ratio of thickness to diameter of pipe is 6, the velocity of inlet air is 25 m/s. The most thermal stress is in inverse proportion to diameter of pipe and velocity of inlet air.

  14. Optimal Management of Geothermal Heat Extraction

    Science.gov (United States)

    Patel, I. H.; Bielicki, J. M.; Buscheck, T. A.

    2015-12-01

    Geothermal energy technologies use the constant heat flux from the subsurface in order to produce heat or electricity for societal use. As such, a geothermal energy system is not inherently variable, like systems based on wind and solar resources, and an operator can conceivably control the rate at which heat is extracted and used directly, or converted into a commodity that is used. Although geothermal heat is a renewable resource, this heat can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal (Rybach, 2003). For heat extraction used for commodities that are sold on the market, sustainability entails balancing the rate at which the reservoir renews with the rate at which heat is extracted and converted into profit, on a net present value basis. We present a model that couples natural resource economic approaches for managing renewable resources with simulations of geothermal reservoir performance in order to develop an optimal heat mining strategy that balances economic gain with the performance and renewability of the reservoir. Similar optimal control approaches have been extensively studied for renewable natural resource management of fisheries and forests (Bonfil, 2005; Gordon, 1954; Weitzman, 2003). Those models determine an optimal path of extraction of fish or timber, by balancing the regeneration of stocks of fish or timber that are not harvested with the profit from the sale of the fish or timber that is harvested. Our model balances the regeneration of reservoir temperature with the net proceeds from extracting heat and converting it to electricity that is sold to consumers. We used the Non-isothermal Unconfined-confined Flow and Transport (NUFT) model (Hao, Sun, & Nitao, 2011) to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are incorporated into the natural resource economics model to determine production strategies that

  15. Heat exchanger analysis on a Microvax II/GPX

    Science.gov (United States)

    Haught, Alan F.

    1988-12-01

    The finite element code FIDAP was used to examine the fluid flow path within a flat plate tube/fin heat exchanger and the resulting heat transfer from the fins and tube walls. The mathematical formulation, mesh development and analysis procedure are presented, and the results obtained are compared with experimental observations of the fluid flow and measurements of the fluid heating. This problem illustrates the capabilities of finite element techniques for analyzing complex three-dimensional convection-dominated heat transfer, and demonstrates the scope of problems which can be addressed on a Micro VAX II/GPX workstation.

  16. Diffusion Welding of Compact Heat Exchangers for Nuclear Applications

    Energy Technology Data Exchange (ETDEWEB)

    Denis Clark; Ron Mizia; Dr. Michael V. Glazoff; Mr. Michael W. Patterson

    2012-06-01

    The next-­-generation nuclear plant (NGNP) is designed to be a flexible source of energy, producing various mixes of electrical energy and process heat (for example, for hydrogen generation) on demand. Compact heat exchangers provide an attractive way to move energy from the helium primary reactor coolant to process heat uses. For process heat efficiency, reactor outlet temperatures of 750-­-900°C are desirable. There are minor but deleterious components in the primary coolant; the number of alloys that can handle this environment is small. The present work concentrates on Alloys 800H and 617.

  17. Dynamic tube/support interaction in heat exchanger tubes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S.S.

    1991-01-01

    The supports for heat exchanger tubes are usually plates with drilled holes; other types of supports also have been used. To facilitate manufacture and to allow for thermal expansion of the tubes, small clearances are used between tubes and tube supports. The dynamics of tube/support interaction in heat exchangers is fairly complicated. Understanding tube dynamics and its effects is important for heat exchangers. This paper summarizes the current state of the art on this subject and to identify future research needs. Specifically, the following topics are discussed: dynamics of loosely supported tubes, tube/support gap dynamics, tube response in flow, tube damage and wear, design considerations, and future research needs. 55 refs., 1 fig.

  18. Near-Term Laser Launch Capability: The Heat Exchanger Thruster

    Science.gov (United States)

    Kare, Jordin T.

    2003-05-01

    The heat exchanger (HX) thruster concept uses a lightweight (up to 1 MW/kg) flat-plate heat exchanger to couple laser energy into flowing hydrogen. Hot gas is exhausted via a conventional nozzle to generate thrust. The HX thruster has several advantages over ablative thrusters, including high efficiency, design flexibility, and operation with any type of laser. Operating the heat exchanger at a modest exhaust temperature, nominally 1000 C, allows it to be fabricated cheaply, while providing sufficient specific impulse (~600 seconds) for a single-stage vehicle to reach orbit with a useful payload; a nominal vehicle design is described. The HX thruster is also comparatively easy to develop and test, and offers an extremely promising route to near-term demonstration of laser launch.

  19. Compact heat exchanger for power plants; Kompakti siirrin tyoentyy myoes kotimaan voimalaitoksiin

    Energy Technology Data Exchange (ETDEWEB)

    Kinnunen, L. [Energia-lehti, Helsinki (Finland)

    2001-07-01

    Vahterus Oy, located at Kalanti, has manufactured heat exchangers since the beginning of 1990s. About 90% of the equipment produced are exported. In the PSHE (Plate and Shell) solution of the Vahterus heat exchanger the heat is transferred by round plated welded to form a compact package, which is assembled into a cylindrical steel casing. The heat exchanger contains no gaskets or soldered joints, which eliminates the leak risks. Traditional heat exchanges are usually operated at higher temperatures and pressures, but the heat transfer capacities of them are lower. Plate heat exchangers, on the other hand, are efficient, but the application range of them is narrow. Additionally, the rubber gasket of the heat exchange plates, sealing the joints of the heat exchanging plates, does not stand high pressures or temperatures, or corroding fluids. The new welded plate heat exchanger combine the pressure and temperature resistance of tube heat exchangers and the high heat exchange capacity of plate heat exchangers. The new corrosion resisting heat exchanger can be applied for especially hard conditions. The operating temperature range of the PSHE heat exchanger is - 200 - 900 deg C. The pressure resistance is as high as 100 bar. The space requirement of PSHE is only one tenth of the space requirement of traditional tube heat exchangers. Adjusting the number of heat exchanging plates can change the capacity of the heat exchanger. Power range of the heat exchanger can be as high as 80 MW. Due to the corrosion preventive construction and the small dimension the PSHE heat exchanger can be applied for refrigerators using ammonia as refrigerant. These kinds of new Vahterus heat exchangers are in use in 60 countries in more than 2000 refrigerators.

  20. Simulation on Thermal Integrity of the Fin/Tube Brazed Joint of Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    Yiyu QIAN; Feng GAO; Fengjiang WANG; Hui ZHAO

    2003-01-01

    In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the therma

  1. Mapping temperature-induced conformational changes in the Escherichia coli heat shock transcription factor sigma 32 by amide hydrogen exchange

    DEFF Research Database (Denmark)

    Rist, Wolfgang; Jørgensen, Thomas J D; Roepstorff, Peter;

    2003-01-01

    gene transcription. To investigate possible heat-induced conformational changes in sigma 32 we performed amide hydrogen (H/D) exchange experiments under optimal growth and heat shock conditions combined with mass spectrometry. We found a rapid exchange of around 220 of the 294 amide hydrogens at 37...... degrees C, indicating that sigma 32 adopts a highly flexible structure. At 42 degrees C we observed a slow correlated exchange of 30 additional amide hydrogens and localized it to a helix-loop-helix motif within domain sigma 2 that is responsible for the recognition of the -10 region in heat shock...

  2. Performance of a Thermoelectric Device with Integrated Heat Exchangers

    Science.gov (United States)

    Barry, Matthew M.; Agbim, Kenechi A.; Chyu, Minking K.

    2015-06-01

    Thermoelectric devices (TEDs) convert heat directly into electrical energy, making them well suited for waste heat recovery applications. An integrated thermoelectric device (iTED) is a restructured TED that allows more heat to enter the p-n junctions, thus producing a greater power output . An iTED has heat exchangers incorporated into the hot-side interconnectors with flow channels directing the working fluid through the heat exchangers. The iTED was constructed of p- and n-type bismuth-telluride semiconductors and copper interconnectors and rectangular heat exchangers. The performance of the iTED in terms of , produced voltage and current , heat input and conversion efficiency for various flow rates (), inlet temperatures (C) ) and load resistances () with a constant cold-side temperature ( = 0C) was conducted experimentally. An increase in had a greater effect on the performance than did an increase in . A 3-fold increase in resulted in a 3.2-, 3.1-, 9.7-, 3.5- and 2.8-fold increase in and respectively. For a constant of 50C, a 3-fold increase in from 3300 to 9920 resulted in 1.6-, 1.6-, 2.6-, 1.5- and 1.9-fold increases in , , , and respectively.

  3. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mittereder, N.; Poerschke, A.

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.

  4. Characterization of a mini-channel heat exchanger for a heat pump system

    Science.gov (United States)

    Arteconi, A.; Giuliani, G.; Tartuferi, M.; Polonara, F.

    2014-04-01

    In this paper a mini-channel aluminum heat exchanger used in a reversible heat pump is presented. Mini-channel finned heat exchangers are getting more and more interest for refrigeration systems, especially when compactness and low refrigerant charge are desired. Purpose of this paper was to characterize the mini-channel heat exchanger used as evaporator in terms of heat transfer performance and to study the refrigerant distribution in the manifold. The heat exchanger characterization was performed experimentally by means of a test rig built up for this purpose. It is composed of an air-to-air heat pump, air channels for the external and internal air circulation arranged in a closed loop, measurement sensors and an acquisition system. The overall heat transfer capacity was assessed. Moreover, in order to characterize the flow field of the refrigerant in the manifold of the heat exchanger, a numerical investigation of the fluid flow by means of CFD was performed. It was meant to evaluate the goodness of the present design and to identify possible solutions for the future improvement of the manifold design.

  5. The influence of a radiated heat exchanger surface on heat transfer

    Science.gov (United States)

    Morel, Sławomir

    2015-09-01

    The experiment leads to establish the influence of radiated surface development heat exchangers on the values of heat flux transferred with water flowing through the exchangers and placed in electric furnace chamber. The values of emissivity coefficients are given for the investigated metal and ceramic coatings. Analytical calculations have been made for the effect of the heating medium (flame) - uncoated wall and then heating medium (flame) - coated wall reciprocal emissivity coefficients. Analysis of the values of exchanged heat flux were also realized. Based on the measurement results for the base coating properties, these most suitable for spraying the walls of furnaces and heat exchangers were selected, and determined by the intensification of heat exchange effect. These coatings were used to spray the walls of a laboratory waste-heat boiler, and then measurements of fluxes of heat absorbed by the cooling water flowing through the boiler tubes covered with different type coatings were made. Laboratory tests and calculations were also confirmed by the results of full-scale operation on the metallurgical equipment.

  6. The influence of a radiated heat exchanger surface on heat transfer

    Directory of Open Access Journals (Sweden)

    Morel Sławomir

    2015-09-01

    Full Text Available The experiment leads to establish the influence of radiated surface development heat exchangers on the values of heat flux transferred with water flowing through the exchangers and placed in electric furnace chamber. The values of emissivity coefficients are given for the investigated metal and ceramic coatings. Analytical calculations have been made for the effect of the heating medium (flame – uncoated wall and then heating medium (flame – coated wall reciprocal emissivity coefficients. Analysis of the values of exchanged heat flux were also realized. Based on the measurement results for the base coating properties, these most suitable for spraying the walls of furnaces and heat exchangers were selected, and determined by the intensification of heat exchange effect. These coatings were used to spray the walls of a laboratory waste-heat boiler, and then measurements of fluxes of heat absorbed by the cooling water flowing through the boiler tubes covered with different type coatings were made. Laboratory tests and calculations were also confirmed by the results of full-scale operation on the metallurgical equipment.

  7. Effect of Corrugation Angle on Heat Transfer Studies of Viscous Fluids in Corrugated Plate Heat Exchangers

    Directory of Open Access Journals (Sweden)

    B Sreedhara Rao

    2015-04-01

    Full Text Available In the present investigation heat transfer studies are conducted in corrugated plate heat exchangers (PHEs having three different corrugation angles of 300, 400 and 500. The plate heat exchangers have a length of 30 cm and a width of 10 cm with a spacing of 5 mm. Water and 20% glycerol solution are taken as test fluids and hot fluid is considered as heating medium. The wall temperatures are measured along the length of exchanger at seven different locations by means of thermocouples. The inlet and outlet temperatures of test fluid and hot fluid are measured by means of four more thermocouples. The experiments are conducted at a flowrate ranging from 0.5 lpm to 6 lpm with the test fluid. Film heat transfer coefficient and Nusselt number are determined from the experimental data. These values are compared with different corrugation angles. The effects of corrugation angles on heat transfer rates are discussed.

  8. Mechanical Properties of Heat Exchanger Tube Materials at Elevated Temperatures

    Science.gov (United States)

    Kahl, Sören; Zajac, Jozefa; Ekström, Hans-Erik

    Since automotive heat exchangers are operated at elevated temperatures and under varying pressures, both static and dynamic mechanical properties should be known at the relevant temperatures. We have collected elevated-temperature tensile test data, elevated-temperature stress amplitude-fatigue life data, and creep-rupture data in a systematic fashion over the past years. For thin, soft, and braze-simulated heat exchanger tube materials tested inside closed furnaces, none of the well-established methods for crack detection and observation can be applied. In our contribution, we present a simple statistical method to estimate the time required for crack initiation.

  9. THERMAL ANALYSIS OF SHELL AND TUBE HEAT EXCHANGER USING CFD

    OpenAIRE

    Karthikeyan. D

    2016-01-01

    In present day shell and tube heat exchanger is the most common type heat exchanger widely use in oil refinery and other large chemical process, because it suits high pressure application. The process in solving simulation consists of modeling and meshing the basic geometry of...

  10. Exergetic optimisation of a heat exchanger

    NARCIS (Netherlands)

    Cornelissen, R.L.; Hirs, G.G.

    1997-01-01

    Abstract The objective of this paper is to show that for the optimal design of an energy system, where there is a trade-off between exergy saving during operation and exergy use during construction of the energy system, exergy analysis and life cycle analysis should be combined. The two methods are

  11. Thermodynamic optimisation of a heat exchanger

    NARCIS (Netherlands)

    Cornelissen, R.L.; Hirs, G.G.

    1999-01-01

    The objective of this paper is to show that for the optimal design of an energy system, where there is a trade-off between exergy saving during operation and exergy use during construction of the energy system, exergy analysis and life cycle analysis should be combined. An exergy optimisation of a h

  12. Heat-transfer analysis of double-pipe heat exchangers for indirect-cycle SCW NPP

    Science.gov (United States)

    Thind, Harwinder

    SuperCritical-Water-cooled Reactors (SCWRs) are being developed as one of the Generation-IV nuclear-reactor concepts. SuperCritical Water (SCW) Nuclear Power Plants (NPPs) are expected to have much higher operating parameters compared to current NPPs, i.e., pressure of about 25 MPa and outlet temperature up to 625 °C. This study presents the heat transfer analysis of an intermediate Heat exchanger (HX) design for indirect-cycle concepts of Pressure-Tube (PT) and Pressure-Vessel (PV) SCWRs. Thermodynamic configurations with an intermediate HX gives a possibility to have a single-reheat option for PT and PV SCWRs without introducing steam-reheat channels into a reactor. Similar to the current CANDU and Pressurized Water Reactor (PWR) NPPs, steam generators separate the primary loop from the secondary loop. In this way, the primary loop can be completely enclosed in a reactor containment building. This study analyzes the heat transfer from a SCW primary (reactor) loop to a SCW and Super-Heated Steam (SHS) secondary (turbine) loop using a double-pipe intermediate HX. The numerical model is developed with MATLAB and NIST REFPROP software. Water from the primary loop flows through the inner pipe, and water from the secondary loop flows through the annulus in the counter direction of the double-pipe HX. The analysis on the double-pipe HX shows temperature and profiles of thermophysical properties along the heated length of the HX. It was found that the pseudocritical region has a significant effect on the temperature profiles and heat-transfer area of the HX. An analysis shows the effect of variation in pressure, temperature, mass flow rate, and pipe size on the pseudocritical region and the heat-transfer area of the HX. The results from the numerical model can be used to optimize the heat-transfer area of the HX. The higher pressure difference on the hot side and higher temperature difference between the hot and cold sides reduces the pseudocritical-region length, thus

  13. Comparisons of Heat Transfer Performance of a Closed-looped Oscillating Heat Pipe and Closed-looped Oscillating Heat Pipe with Check Valves Heat Exchangers

    Directory of Open Access Journals (Sweden)

    P. Meena

    2008-01-01

    Full Text Available This research was to study the comparisons of heat transfer performance of closed-looped oscillating heat pipe and closed-looped oscillating heat pipe with check valves heat exchangers with R134a, Ethanol and water were used as the working fluids. A set of heat pipe heat exchanger (CLOHP and CLOHP/CV were made of copper tubes in combination of following dimension: 2.03 mm inside diameter: 40 turns, with 20, 10 and 20 cm for evaporator, adiabatic and condenser sections lengths. The working fluid was filled in the tube at the filling ratio of 50%. The evaporator section was given heat by heater while the condenser section was cooled by air. The adiabatic section was properly insulated. In the test operation, it could be concluded as follows. It indicated that the heat transfer performance of closed-looped oscillating heat pipe with check valves heat exchanger better than closed-looped oscillating heat exchanger.

  14. HEAT EXCHANGE NETWORKS IN BIODIESEL PRODUCTION FROM WASTE COOKING OILS

    Directory of Open Access Journals (Sweden)

    María Fernanda Laborde

    2014-11-01

    Full Text Available With the objective to aboard one of the challenges in Engineering teaching: It´s the application in professional practice?, along with attending to the actual requirements of achieve energetic efficiency in industrial process and to reuse wastes of food industry, this work, presents the application of heat exchange networks for the resolution of a real case: pre-treatment of waste cooking oils (WCO withacid catalysis for biodiesel production. Different methods and software are applied to obtain the minimum amounts of heat and the heat exchange network for a processing capacity of 0,19 kg/s of WCO. A minimum temperature difference (Tmin of 10°C is considered and the minimum requirements of heating and cooling result 4629,87 W and 10066,30 W, respectively. If this exchange network is not considered, this values increase to 26838,33 W and 21958,33 W, respectively. Applying heat exchange network, decrease 78,92% the required steam service in the process and water cooling service decreases 62,48%, demonstrating that integration reduces energetic requirements respect the non-integrated process.

  15. Method for Incorporation of Controllability in Heat Exchanger Network Synthesis by Integrating Mathematical Programming and Knowledge Engineering

    Institute of Scientific and Technical Information of China (English)

    李志红

    2002-01-01

    A method for incorporation of controlling the heat exchanger networks with or without splits is proposed by integrating mathematical programming and knowledge engineering.The simultaneous optimal mathematical model is established.This method can be practically used in the integration of large-scale heat exchanger networks,not only to synthesize automatically but also to satisfy the requirement of structural controllability with more nobjective human intervention.

  16. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

    Science.gov (United States)

    Ungar, Eugene K.; Schunk, Richard G.

    2011-01-01

    An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

  17. ASME code considerations for the compact heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Nestell, James [MPR Associates Inc., Alexandria, VA (United States); Sham, Sam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-31

    The mission of the U.S. Department of Energy (DOE), Office of Nuclear Energy is to advance nuclear power in order to meet the nation's energy, environmental, and energy security needs. Advanced high temperature reactor systems such as sodium fast reactors and high and very high temperature gas-cooled reactors are being considered for the next generation of nuclear reactor plant designs. The coolants for these high temperature reactor systems include liquid sodium and helium gas. Supercritical carbon dioxide (sCO₂), a fluid at a temperature and pressure above the supercritical point of CO₂, is currently being investigated by DOE as a working fluid for a nuclear or fossil-heated recompression closed Brayton cycle energy conversion system that operates at 550°C (1022°F) at 200 bar (2900 psi). Higher operating temperatures are envisioned in future developments. All of these design concepts require a highly effective heat exchanger that transfers heat from the nuclear or chemical reactor to the chemical process fluid or the to the power cycle. In the nuclear designs described above, heat is transferred from the primary to the secondary loop via an intermediate heat exchanger (IHX) and then from the intermediate loop to either a working process or a power cycle via a secondary heat exchanger (SHX). The IHX is a component in the primary coolant loop which will be classified as "safety related." The intermediate loop will likely be classified as "not safety related but important to safety." These safety classifications have a direct bearing on heat exchanger design approaches for the IHX and SHX. The very high temperatures being considered for the VHTR will require the use of very high temperature alloys for the IHX and SHX. Material cost considerations alone will dictate that the IHX and SHX be highly effective; that is, provide high heat transfer area in a small volume. This feature must be accompanied by low pressure drop and mechanical reliability and

  18. Thermal Analysis of Fin and Tube Heat Exchanger

    OpenAIRE

    2014-01-01

    This paper studied experimentally the effect of heat transfer of fin and tube type heat exchanger for different mass flow rate of fluid. The thermal stresses induced on fin and tube is also studied by ansys software at steady state condition by changing the width of fin and diameter of tube. Readings were taken experimentally by changing mass flow rate of fluid at respective temperatures. Comparison was done on theoretically and experimentally obtained results. It is observed ...

  19. Automatización y optimización del diseño de intercambiadores de calor de tubo y coraza mediante el método de Taborek//Automatization and optimization of shell and tube heat exchangers design using the method of Taborek

    Directory of Open Access Journals (Sweden)

    Maida Bárbara Reyes‐Rodríguez

    2014-01-01

    Full Text Available Los intercambiadores de calor del tipo de coraza y tubo constituyen la parte más importante de los equipos de transferencia de calor sin combustión en las plantas de procesos químicos. Existen en la literatura numerosos métodos para el diseño de Intercambiadores de calor de tubo y coraza. Entre los más conocidos se encuentran el Método de Kern, el Método de Bell Delaware, el Método de Tinker, elMétodo de Wills and Johnston y el Método de Taborek. El presente trabajo tiene como objetivo describir y automatizar el método de Taborek. Se realiza además la optimización del Costo del Intercambiador de Calor mediante el método de Recocido Simulado y el método de los algoritmos genéticos. Se puede concluir que la optimización por ambos métodos arroja resultados similares, disminuyendoapreciablemente el costo del intercambiador optimizado.Palabras claves: optimización, intercambiadores de calor, método de Taborek, algoritmos genéticos.______________________________________________________________________________AbstractShell and tube heat exchangers are the most important equipment for heat transfer without combustion in plants of chemical processes.There are many methods for designing shell and tube heat exchangers in literature. Among the most known are the Kern´s Method, the Method of Bell Delaware, the Method ofTinker, the Method of Wills and Johnston and the Method of Taborek. The objective of this paper is to describe and automate the Taborek´s method. It is also realized and optimization of the heat exchanger cost using the genetic algorithm and Simulated Annealing. It can be concluded that the optimization usingboth methods conduces to similar results, diminishing considerably the optimized exchanger cost.Key words: optimization, Heat Exchangers, Taborek, Genetic Algorithms.

  20. Heat transfer characteristics of a new helically coiled crimped spiral finned tube heat exchanger

    Science.gov (United States)

    Srisawad, Kwanchanok; Wongwises, Somchai

    2009-02-01

    In the present study, the heat transfer characteristics in dry surface conditions of a new type of heat exchanger, namely a helically coiled finned tube heat exchanger, is experimentally investigated. The test section, which is a helically coiled fined tube heat exchanger, consists of a shell and a helical coil unit. The helical coil unit consists of four concentric helically coiled tubes of different diameters. Each tube is constructed by bending straight copper tube into a helical coil. Aluminium crimped spiral fins with thickness of 0.5 mm and outer diameter of 28.25 mm are placed around the tube. The edge of fin at the inner diameter is corrugated. Ambient air is used as a working fluid in the shell side while hot water is used for the tube-side. The test runs are done at air mass flow rates ranging between 0.04 and 0.13 kg/s. The water mass flow rates are between 0.2 and 0.4 kg/s. The water temperatures are between 40 and 50°C. The effects of the inlet conditions of both working fluids flowing through the heat exchanger on the heat transfer coefficients are discussed. The air-side heat transfer coefficient presented in term of the Colburn J factor is proportional to inlet-water temperature and water mass flow rate. The heat exchanger effectiveness tends to increase with increasing water mass flow rate and also slightly increases with increasing inlet water temperature.

  1. Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

    Science.gov (United States)

    Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Lacomini, Christie; Paul, Heather L.

    2009-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2-selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (L CO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas represents a significant source of potential energy for the warming of the adsorbent bed as it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously.

  2. Structure and Output Characteristics of a TEM Array Fitted to a Fin Heat Exchanger

    Science.gov (United States)

    Zhang, Z.; Chen, L. N.; Chen, Z. J.; Xiao, G. Q.; Liu, Z. J.

    2015-06-01

    In the design of a thermoelectric generator, both the heat transfer area and the number of thermoelectric modules (TEMs) should be increased accordingly as the generator power increases; crucially, both aspects need to be coordinated. A kilowatt thermoelectric generator with a fin heat exchanger is proposed for use in a constant-speed diesel generator unit. Interior fins enhance convective heat transfer, whereas an exterior fin segment increases the heat transfer area. The heat transfer surface is double that of a plane heat exchanger, and the temperature field over the exterior fins is constrained to a one-dimensional distribution. Between adjoining exterior fins, there is a cooling water channel with trapezoid cross-section, enabling compact TEMs and cooling them. Hence, more TEMs are built as a series-parallel array of TEMs with lower resistance and more stable output current. Under nonuniform conditions, to prevent circulation and energy loss, bypass diodes and antidiodes are added. Experiments and numerical calculations show that, with matching and optimization of the heat exchanger and TEM array, a stable maximum output power is obtainable from the interior of the thermoelectric generator system, which can be connected to an external maximum power point tracking system.

  3. Compact/micro heat exchangers – Their role in heat pumping equipment

    OpenAIRE

    Kew, PA; Reay, DA; 2nd Micro and Nano Flows Conference (MNF2009)

    2009-01-01

    This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications. Compact and micro-heat exchangers have many advantages over their larger ...

  4. Compact/micro heat exchangers – Their role in heat pumping equipment

    OpenAIRE

    Kew, PA; Reay, DA; 2nd Micro and Nano Flows Conference (MNF2009)

    2009-01-01

    This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications. Compact and micro-heat exchangers have many advantages over their larger ...

  5. A novel compact heat exchanger using gap flow mechanism

    Science.gov (United States)

    Liang, J. S.; Zhang, Y.; Wang, D. Z.; Luo, T. P.; Ren, T. Q.

    2015-02-01

    A novel, compact gap-flow heat exchanger (GFHE) using heat-transfer fluid (HTF) was developed in this paper. The detail design of the GFHE coaxial structure which forms the annular gap passage for HTF is presented. Computational fluid dynamics simulations were introduced into the design to determine the impacts of the gap width and the HTF flow rate on the GFHE performance. A comparative study on the GFHE heating rate, with the gap widths ranged from 0.1 to 1.0 mm and the HTF flow rates ranged from 100 to 500 ml/min, was carried out. Results show that a narrower gap passage and a higher HTF flow rate can yield a higher average heating rate in GFHE. However, considering the compromise between the GFHE heating rate and the HTF pressure drop along the gap, a 0.4 mm gap width is preferred. A testing loop was also set up to experimentally evaluate the GFHE capability. The testing results show that, by using 0.4 mm gap width and 500 ml/min HTF flow rate, the maximum heating rate in the working chamber of the as-made GFHE can reach 18 °C/min, and the average temperature change rates in the heating and cooling processes of the thermal cycle test were recorded as 6.5 and 5.4 °C/min, respectively. These temperature change rates can well satisfy the standard of IEC 60068-2-14:2009 and show that the GFHE developed in this work has sufficient heat exchange capacity and can be used as an ideal compact heat exchanger in small volume desktop thermal fatigue test apparatus.

  6. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mittereder, Nick [IBACOS, Inc., Pittsburgh, PA (United States); Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season.

  7. Assessment of Real Heat Transfer Coefficients through Shell and Tube and Plate Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Dan CONSTANTINESCU

    2011-07-01

    Full Text Available The purpose of this paper is to present a procedure used in the assessment of the real heat transfer characteristic of shell and tube and plate heat exchangers. The theoretical fundamentals of the procedure are introduced as well as the measured data collection and processing. The theoretical analysis is focused on the adoption of criterial equations which, subjected to certain verification criteria presented in the paper, provide the most credible value of the convection heat transfer coefficients inside the circular and flat tubes. In the end two case studies are presented, one concerning a shell and tube heat exchanger operational at INCERC Thermal Substation and the other concerning a plate heat exchanger tested on the Laboratory Stand of the Department of Building Services and Efficient Use of Energy in Buildings of INCERC Bucharest.

  8. Fouling characteristics of compact heat exchangers and enhanced tubes.

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, C. B.; Rabas, T. J.

    1999-07-15

    Fouling is a complex phenomenon that (1) encompasses formation and transportation of precursors, and (2) attachment and possible removal of foulants. A basic understanding of fouling mechanisms should guide the development of effective mitigation techniques. The literature on fouling in complex flow passages of compact heat exchangers is limited; however, significant progress has been made with enhanced tubes.

  9. 40 CFR 63.654 - Heat exchange systems.

    Science.gov (United States)

    2010-07-01

    ... Emission Standards for Hazardous Air Pollutants From Petroleum Refineries § 63.654 Heat exchange systems..., Sampling Procedures Manual, Appendix P: Cooling Tower Monitoring, prepared by Texas Commission on..., dated January 2003, Sampling Procedures Manual, Appendix P: Cooling Tower Monitoring, prepared by Texas...

  10. Characteristics of Vertical Mantle Heat Exchangers for Solar Water Heaters

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Morrison, G.L.; Behnia, M.

    1999-01-01

    exchangers was also developed for detailed evaluation of the heat flux distribution over the mantle surface. Both the experimental and simulation results indicate that distribution of the flow around the mantle gap is governed by buoyancy driven recirculation in the mantle. The operation of the mantle...

  11. Potential heat exchange fluids for use in sulfuric acid vaporizers

    Science.gov (United States)

    Lawson, D. D.; Petersen, G. R.

    1981-01-01

    A series of liquids have been screened as candidate heat exchange fluids for service in thermochemical cycles that involve the vaporization of sulfuric acid. The required chemical and physical criteria of the liquids is described with the results of some preliminary high temperature test data presented.

  12. Heat-Exchange Fluids for Sulfuric Acid Vaporizers

    Science.gov (United States)

    Lawson, D. D.; Petersen, G. R.

    1982-01-01

    Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because vapor pressure of material decreases as DP increases, and high-DP liquids have lower loss due to vaporization.

  13. Teaching Heat Exchanger Network Synthesis Using Interactive Microcomputer Graphics.

    Science.gov (United States)

    Dixon, Anthony G.

    1987-01-01

    Describes the Heat Exchanger Network Synthesis (HENS) program used at Worcester Polytechnic Institute (Massachusetts) as an aid to teaching the energy integration step in process design. Focuses on the benefits of the computer graphics used in the program to increase the speed of generating and changing networks. (TW)

  14. High temperature heat exchangers for gas turbines and future hypersonic air breathing propulsion

    Science.gov (United States)

    Avran, Patrick; Bernard, Pierre

    After surveying the results of ONERA's investigations to date of metallic and ceramic heat exchangers applicable to automotive and aircraft powerplants, which are primarily of finned-tube counterflow configuration, attention is given to the influence of heat-exchanger effectiveness on fuel consumption and exchanger dimensions and weight. Emphasis is placed on the results of studies of cryogenic heat exchangers used by airbreathing hypersonic propulsion systems. The numerical codes developed by ONERA for the modeling of heat exchanger thermodynamics are evaluated.

  15. Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger

    Science.gov (United States)

    Greene, William D. (Inventor)

    2008-01-01

    A dual expander cycle (DEC) rocket engine with an intermediate closed-cycle heat exchanger is provided. A conventional DEC rocket engine has a closed-cycle heat exchanger thermally coupled thereto. The heat exchanger utilizes heat extracted from the engine's fuel circuit to drive the engine's oxidizer turbomachinery.

  16. Catalytic heat exchangers - a long-term evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Silversand, Fredrik A. [CATATOR AB, Lund (Sweden)

    2003-10-01

    A long-term evaluation concerning catalytic heat exchangers (CHEs) has been performed. The idea concerning CHEs was originally described in a number of reports issued by Catator almost a decade ago. The general idea with CHEs is to combust a fuel with a catalyst inside a heat exchanger to enable an effective heat transfer. The first design approaches demonstrated the function and the possibilities with CHEs but were defective concerning the heat exchanger design. Consequently, a heat exchanger company (SWEP International AB), which was specialised on brazed plate-type heat exchangers, joined the continued development project. Indeed, the new design approach containing Catator's wire-mesh catalysts and SWEP's plate-type heat exchangers enabled us to improve the concept considerably. The new design complied with a number of relevant technical demands, e.g.: Simplicity; Compactness and integration (few parts); High thermal efficiency; Low pressure drop; Excellent emissions; High turn-down ratio; Reasonable production cost. Spurred by the technical progresses, the importance of a long-term test under realistic conditions was clear. A long-term evaluation was initialised at Sydkraft Gas premises in Aastorp. The CHE was installed on a specially designed rig to enable accelerated testing with respect to the number of transients. The rig was operated continuously for 5000 hours and emission mapping was carried out at certain time intervals. Following some problems during the initial phase of the long-term evaluation, which unfortunately also delayed the project, the results indicated very stable conditions of operation. The emissions have been rather constant during the course of the test and we cannot see any tendencies to decreased performances. Indeed, the test verifies the function, operability and reliability of the CHE-concept. Apart from domestic boilers we foresee a number of interesting and relevant applications in heating and process technology. Since

  17. A survey of oscillating flow in Stirling engine heat exchangers

    Science.gov (United States)

    Simon, Terrence W.; Seume, Jorge R.

    1988-01-01

    Similarity parameters for characterizing the effect of flow oscillation on wall shear stress, viscous dissipation, pressure drop and heat transfer rates are proposed. They are based on physical agruments and are derived by normalizing the governing equations. The literature on oscillating duct flows, regenerator and porous media flows is surveyed. The operating characteristics of the heat exchanger of eleven Stirling engines are discribed in terms of the similarity parameters. Previous experimental and analytical results are discussed in terms of these parameters and used to estimate the nature of the oscillating flow under engine operating conditions. The operating points for many of the modern Stirling engines are in or near the laminar to turbulent transition region. In several engines, working fluid does not pass entirely through heat exchangers during a cycle. Questions that need to be addressed by further research are identified.

  18. Studi Eksperimen Analisa Performa Compact Heat Exchanger Louvered Fin Flat Tube untuk pemanfaatan Waste Energy

    Directory of Open Access Journals (Sweden)

    Taqwim Ismail

    2014-03-01

    Full Text Available Waste Heat Recovery merupakan instalasi yang digunakan untuk memanfaatkan kembali waste energy seperti exhaust gas. Penelitian dilakukan pada compact heat exchanger tipe louvered fin flat tube sebagai salah satu komponen penyusun waste heat recovery system. Eksperimen dilakukan dengan mendesain compact heat exchanger tipe louvered fin flat tube kemudian dilakukan pengujian pada compact heat exchanger yang telah didesain. Pengujian dilakukan dengan memberikan tiga variasi kecepatan putaran fan sisi exhaust gas, yaitu 0.2, 0.3, dan 0.4 m/s untuk mengetahui unjuk kerja yang berbeda dari compact heat exchanger yang telah didesain.  Hasil yang didapatkan dari studi eksperimen ini adalah dimensi dari compact heat exchanger tipe louvered fin flat tube dan beberapa parameter yang menunjukkan unjuk kerja dari compact heat exchanger seperti nilai heat transfer baik dari sisi air maupun sisi exhaust gas, effectiveness, number of transfer unit (NTU, overall heat transfer coefficient, dan  ΔTLMTD dari compact heat exchanger.

  19. VHTR engineering design study: intermediate heat exchanger program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-11-01

    The work reported is the result of a follow-on program to earlier Very High Temperature Reactor (VHTR) studies. The primary use of the VHTR is to provide heat for various industrial processes, such as hydrocarbon reforming and coal gasification. For many processes the use of an intermediate heat transfer barrier between the reactor coolant and the process is desirable; for some processes it is mandatory. Various intermediate heat exchanger (IHX) concepts for the VHTR were investigated with respect to safety, cost, and engineering design considerations. The reference processes chosen were steam-hydrocarbon reforming, with emphasis on the chemical heat pipe, and steam gasification of coal. The study investigates the critically important area of heat transfer between the reactor coolant, helium, and the various chemical processes.

  20. Heat exchanger modeling and identification for control of waste heat recovery systems in diesel engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.P.T.; Rojer, C.; Jager, B. de; Steinbuch, M.

    2013-01-01

    To meet future CO2 emission targets, Waste Heat Recovery systems have recently attracted much attention for automotive applications, especially for long haul trucks. This paper focuses on the development of a dynamic counter-flow heat exchanger model for control purposes. The model captures the dyna

  1. Modeling heat efficiency, flow and scale-up in the corotating disc scraped surface heat exchanger

    DEFF Research Database (Denmark)

    Friis, Alan; Szabo, Peter; Karlson, Torben

    2002-01-01

    A comparison of two different scale corotating disc scraped surface heat exchangers (CDHE) was performed experimentally. The findings were compared to predictions from a finite element model. We find that the model predicts well the flow pattern of the two CDHE's investigated. The heat transfer...

  2. Heat exchanger modeling and identification for control of waste heat recovery systems in diesel engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.P.T.; Rojer, C.; Jager, B. de; Steinbuch, M.

    2013-01-01

    To meet future CO2 emission targets, Waste Heat Recovery systems have recently attracted much attention for automotive applications, especially for long haul trucks. This paper focuses on the development of a dynamic counter-flow heat exchanger model for control purposes. The model captures the dyna

  3. HEAT TRANSFER COEFFICIENT AND FRICTION FACTOR CHARACTERISTICS OF A GRAVITY ASSISTED BAFFLED SHELL AND HEAT-PIPE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    P. Raveendiran

    2015-06-01

    Full Text Available The heat transfer coefficients and friction factors of a baffled shell and heat pipe heat exchanger with various inclination angles were determined experimentally; using methanol as working fluid and water as heat transport fluid were reported. Heat pipe heat exchanger reported in this investigation have inclination angles varied between 15o and 60o for different mass flow rates and temperature at the shell side of the heat exchanger. All the required parameters like outlet temperature of both hot and cold side of heat exchanger and mass flow rate of fluids were measured using an appropriate instrument. Different tests were performed from which condenser side heat transfer coefficient and friction factor were calculated. In all operating conditions it has been found that the heat transfer coefficient increases by increasing the mass flow rate and angle of inclination. The reduction in friction factor occurs when the Reynolds number is increased. The overall optimum experimental effectiveness of GABSHPHE has found to be 42% in all operating conditioning at ψ = 45o.

  4. Next Generation Nuclear Plant Intermediate Heat Exchanger Acquisition Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Mizia, Ronald Eugene [Idaho National Laboratory

    2008-04-01

    DOE has selected the High Temperature Gas-cooled Reactor (HTGR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900°C to 950°C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium cooled, prismatic or pebble-bed reactor, and use low-enriched uranium, TRISO-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development (R&D) Program is responsible for performing R&D on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while at the same time setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. The purpose of this report is to address the acquisition strategy for the NGNP Intermediate Heat Exchanger (IHX).This component will be operated in flowing, impure helium on the primary and secondary side at temperatures up to 950°C. There are major high temperature design, materials availability, and fabrication issues that need to be addressed. The prospective materials are Alloys 617, 230, 800H and X, with Alloy 617 being the leading candidate for the use at 950°C. The material delivery schedule for these materials does not pose a problem for a 2018 start up as the vendors can quote reasonable delivery times at the moment. The product forms and amount needed must be finalized as soon as possible. An

  5. Active heat exchange system development for latent heat thermal energy storage

    Science.gov (United States)

    Lefrois, R. T.; Mathur, A. K.

    1980-04-01

    Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

  6. Active heat exchange system development for latent heat thermal energy storage

    Science.gov (United States)

    Lefrois, R. T.; Mathur, A. K.

    1980-01-01

    Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

  7. HYSYS Automation and Its Application on Evaluation of Plate Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    Dai Yuqiang; Liu Wenwei; Wang Shaomin; Hu Dapeng

    2008-01-01

    When simulating or designing plate heat exchangers for multicomponent mixtures, most de-signers are often perplexed with the question on how to choose or estimate the physical property param-eters and hope to have a reliable database that could be adopted. The commercial codes HYSYS supply the physical property package on over 1500 pure substances and over 16 000 binary coefficients for them.This work has briefly presented an efficient communication interface based on the Microsoft Component Object Model (COM) between inner plate heat exchanger simulation codes and the HYSYS package. The application of a custom-made HYSYS-COM interface has shown high efficiency, such as significant re-duction of time needed for evaluating each process stream's properties. This automation method can be conveniently extended to further optimization study for any specific operation device such as heat transfers,columns, and other facilities.

  8. A one-dimensional heat transfer model for parallel-plate thermoacoustic heat exchangers.

    Science.gov (United States)

    de Jong, J A; Wijnant, Y H; de Boer, A

    2014-03-01

    A one-dimensional (1D) laminar oscillating flow heat transfer model is derived and applied to parallel-plate thermoacoustic heat exchangers. The model can be used to estimate the heat transfer from the solid wall to the acoustic medium, which is required for the heat input/output of thermoacoustic systems. The model is implementable in existing (quasi-)1D thermoacoustic codes, such as DeltaEC. Examples of generated results show good agreement with literature results. The model allows for arbitrary wave phasing; however, it is shown that the wave phasing does not significantly influence the heat transfer.

  9. Numerical Simulation of Heat Transfer in a Gas Solid Crossflow Moving Packed Bed Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    Anyuan Liu; Shi Liu; Yufeng Duan; Zhonggang Pan

    2001-01-01

    The mechanism of heat transfer in a crossfiow moving packed bed heat transfer exchanger is analyzed and a two dimensional heat transfer mathematical model has been developed based on the two fluid model (TFM) approach, in which both phases are considered to be continuous and fully interpenetrating. This model is solved by means of numerical method and the results are approximately in agreement with the experimental ones.

  10. Thermoacoustics with idealized heat exchangers and no stack.

    Science.gov (United States)

    Wakeland, Ray Scott; Keolian, Robert M

    2002-06-01

    A model is developed for thermoacoustic devices that have neither stack nor regenerator. These "no-stack" devices have heat exchangers placed close together in an acoustic standing wave of sufficient amplitude to allow individual parcels of gas to enter both exchangers. The assumption of perfect heat transfer in the exchangers facilitates the construction of a simple model similar to the "moving parcel picture" that is used as a first approach to stack-based engines and refrigerators. The model no-stack cycle is shown to have potentially greater inviscid efficiency than a comparable stack model. However, losses from flow through the heat exchangers and on the walls of the enclosure are greater than those in a stack-based device due to the increased acoustic pressure amplitude. Estimates of these losses in refrigerators are used to compare the possible efficiencies of real refrigerators made with or without a stack. The model predicts that no-stack refrigerators can exceed stack-based refrigerators in efficiency, but only for particular enclosure geometries.

  11. Optimal portfolio performance with exchange traded funds

    OpenAIRE

    Petronio, Filomena; Lando, Tommaso; Biglova, Almira; Ortobelli, Sergio

    2014-01-01

    In this paper, the portfolio selection problem in exchange-traded fund (hereafter ETF) markets is considered. Since the ETFs track some market indexes with lower costs than the indexes, their development and popularity is grown enormously in the last decade. Moreover, ETF characteristics also present several advantages for the investors that we briefly examine for the U.S. and European markets of ETFs. In particular, we first introduce a new performance measure consistent with the...

  12. φ7 mm管翅式换热器的翅片孔直径优化%Optimization of fin-hole diameter for φ7 mm finned-tube heat exchanger

    Institute of Scientific and Technical Information of China (English)

    钟明生; 倪雪辉; 黄起建

    2016-01-01

    通过对过盈量的分析,设计与φ7 mm内螺纹铜管配合的几种翅片孔直径的换热器,分析对比换热器的穿管阻力、U形管报废率、穿管效率以及换热能力,发现在翅片孔直径为7.27 mm时,以上4项参数能够达到最佳配合。并对胀后铜管受力变形、铜管外径、齿形变化及翅片间距分布进行分析。%Through the analysis on the magnitude of interference ,the heat exchangers with several different fin‐hole diameters suited to φ7 mm inner grooved copper tube are de‐signed .Through the analysis and comparison of the heat exchanger’s tube‐inserting resist‐ance ,U‐tube scrap rate ,tube‐inserting efficiency and heat transfer capability ,it’ s found that w hen the fin‐hole diameter is 7 .27 mm ,above four items can achieve the best fit .In addition ,the force deformation of the copper tube ,the diameter of the copper tube ,the change of the tooth profile and the distribution of the fin spacing for the expanded copper tube are analyzed .

  13. Airside performances of finned eight-tube heat exchangers

    Science.gov (United States)

    Li, Cheng; Li, Junming

    2016-11-01

    For applications in the relatively low temperature refrigeration systems with large constant temperature bath, the present work performed the experimental studies on the airside performances of the staggered finned eight-tube heat exchangers with large fin pitches. The airside heat transfer coefficients and pressure drops for three fin types and two fin pitches are obtained and analyzed. The heat transfer enhancement with louver fins is 11-16 % higher than the flat fins and that with sinusoidal corrugated fins is 1.1-3.4 % higher than the flat fins. Higher Re brings larger enhancement for various fins. Fin pitches show weak influence on heat transfer for eight tube rows. However, effects of fin pitch on heat transfer for both the sinusoidal corrugation and the louvered fin are larger than the flat fins and they are different from those for N ≤ 6. Airside Colburn j factor are compared with previous and it could be concluded that the airside j factor is almost constant for finned tube heat exchangers with eight tubes and large fin pitches, when Re is from 250 to 2500. The results are different from previous studies for fewer tube rows.

  14. Experimental Investigation of Ice Phase Change Material Heat Exchangers

    Science.gov (United States)

    Leimkuehler, Thomas O.; Stephan, Ryan A.

    2012-01-01

    Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

  15. Subscale Water Based Phase Change Material Heat Exchanger Development

    Science.gov (United States)

    Sheth, Rubik; Hansen, Scott

    2016-01-01

    Supplemental heat rejection devices are required in many spacecraft as the radiators are not sized to meet the full heat rejection demand. One means of obtaining additional heat rejection is through the use of phase change material heat exchangers (PCM HX's). PCM HX's utilize phase change to store energy in unfavorable thermal environments (melting) and reject the energy in favorable environments (freezing). Traditionally, wax has been used as a PCM on spacecraft. However, water is an attractive alternative because it is capable of storing about 40% more energy per unit mass due to its higher latent heat of fusion. The significant problem in using water as a PCM is its expansion while freezing, leading to structural integrity concerns when housed in an enclosed heat exchanger volume. Significant investigation and development has taken place over the past five years to understand and overcome the problems associated with water PCM HX's. This paper reports on the final efforts by Johnson Space Center's Thermal Systems Branch to develop a water based PCM HX. The test article developed and reported on is a subscale version of the full-scale water-based PCM HX's constructed by Mezzo Technologies. The subscale unit was designed by applying prior research on freeze front propagation and previous full-scale water PCM HX development. Design modifications to the subscale unit included use of urethane bladder, decreased aspect ratio, perforated protection sheet, and use of additional mid-plates. Testing of the subscale unit was successful and 150 cycles were completed without fail.

  16. Simulation of embedded heat exchangers of solar aided ground source heat pump system

    Institute of Scientific and Technical Information of China (English)

    王芳; 郑茂余; 邵俊鹏; 李忠建

    2008-01-01

    Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year’s running. It is beneficial for the system to operate for long period.

  17. Fabrication of Wire Mesh Heat Exchangers for Waste Heat Recovery Using Wire-Arc Spraying

    Science.gov (United States)

    Rezaey, R.; Salavati, S.; Pershin, L.; Coyle, T.; Chandra, S.; Mostaghimi, J.

    2014-04-01

    Waste heat can be recovered from hot combustion gases using water-cooled heat exchangers. Adding fins to the external surfaces of the water pipes inserted into the hot gases increases their surface area and enhances heat transfer, increasing the efficiency of heat recovery. A method of increasing the heat transfer surface area has been developed using a twin wire-arc thermal spray system to generate a dense, high-strength coating that bonds wire mesh to the outside surfaces of stainless steel pipes through which water passes. At the optimum spray distance of 150 mm, the oxide content, coating porosity, and the adhesion strength of the coating were measured to be 7%, 2%, and 24 MPa, respectively. Experiments were done in which heat exchangers were placed inside a high-temperature oven with temperature varying from 300 to 900 °C. Several different heat exchanger designs were tested to estimate the total heat transfer in each case. The efficiency of heat transfer was found to depend strongly on the quality of the bond between the wire meshes and pipes and the size of openings in the wire mesh.

  18. Optimal usage of low temperature heat sources to supply district heating by heat pumps

    DEFF Research Database (Denmark)

    Pieper, Henrik; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2017-01-01

    This paper presents a theoretical study on the optimal usage of different low temperature heat sources to supply district heating by heat pumps. The study is based on data for the Copenhagen region. The heat sources were prioritized based on the coefficient of performance calculated for each hour....... Groundwater, seawater and air heat sources were compared with each other as well as to a scenario consisting of a combination of these heat sources. In addition, base load and peak load units were included. Characteristic parameters were the coefficient of performance, the number of full load hours...

  19. Design and economic investigation of shell and tube heat exchangers using Improved Intelligent Tuned Harmony Search algorithm

    Directory of Open Access Journals (Sweden)

    Oguz Emrah Turgut

    2014-12-01

    Full Text Available This study explores the thermal design of shell and tube heat exchangers by using Improved Intelligent Tuned Harmony Search (I-ITHS algorithm. Intelligent Tuned Harmony Search (ITHS is an upgraded version of harmony search algorithm which has an advantage of deciding intensification and diversification processes by applying proper pitch adjusting strategy. In this study, we aim to improve the search capacity of ITHS algorithm by utilizing chaotic sequences instead of uniformly distributed random numbers and applying alternative search strategies inspired by Artificial Bee Colony algorithm and Opposition Based Learning on promising areas (best solutions. Design variables including baffle spacing, shell diameter, tube outer diameter and number of tube passes are used to minimize total cost of heat exchanger that incorporates capital investment and the sum of discounted annual energy expenditures related to pumping and heat exchanger area. Results show that I-ITHS can be utilized in optimizing shell and tube heat exchangers.

  20. RESEARCH OF SHORT DIFFUSERS IMPLEMENTATION EFFICIENCY IN COMPACT HEAT EXCHANGERS

    Directory of Open Access Journals (Sweden)

    Yusha V.L

    2014-12-01

    Full Text Available Increasing of efficiency of air condenser with the help of cooling air distribution is considered. The relevance of research connected with preservation of the compact sizes of the heat exchange device is presented. The analysis of shortcomings of the existing designs on the basis of the tubular heat exchanger with the short diffuser is carried out. Various devices and recommendations about improvement of operation of the short diffuser are considered. The research objective consisting in an assessment of influence of a configuration of flowing part of the short diffuser on overall performance of the heat exchange device is formulated. The methodology of carrying out the engineering analysis of cooling equipment on the base of ANSYS CFX is developed. The calculation of tubular cooler characteristics with several alternatives of the inlet section is made, the analysis of results from the point of view of losses of pressure in the diffuser and amounts of the taken-away heat is carried out. The improvement in cooler work using guide rails for its inlet section is discovered.

  1. Studi Eksperimen Pengaruh Variasi Kecepatan Udara Terhadap Performa Heat Exchanger Jenis Compact Heat Exchanger (Radiator Dengan Susunan Tube Inline Sebagai Pemanas Pada Sistem Pengeringan Batubara

    Directory of Open Access Journals (Sweden)

    Irvan Paramananda

    2014-03-01

    Full Text Available Pengeringan yang dilakukan pada batu bara dengan memanfaatkan udara panas menggunakan konsep heat exchanger. Salah satu heat exchanger yang sering digunakan adalah heat exchanger dengan tipe single row-fin tube yaitu radiator. Radiator ini akan dimanfaatkan sebagai penghasil udara panas dari air panas yang mengalir dan dihembuskan oleh kipas radiator. Penelitian ini difokuskan pada effectiveness dari komponen radiator fungsi dari kecepatan udara mulai dari kecepatan 1 m/s, 2 m/s, 3 m/s, 4 m/s dan 5 m/s dan fungsi jumlah radiator yang digunakan. Prinsip dari radiator yang digunakan adalah mengalirkan fluida panas berupa air ke dalam tube-tube radiator kemudian didinginkan oleh udara yang dihembuskan oleh fan yang melewati fin sehingga air yang keluar dari tube menjadi dingin dan udara yang melewati fin menjadi panas. Hasil yang didapatkan dari eksperimen ini diantaranya kecepatan udara yang optimal terhadap proses pengeringan batu bara yang dipakai pada alat pengering batu bara adalah sebesar 5 m/s dengan menggunakan 2 radiator. qhot untuk penggunaan 2 radiator dengan kecepatan udara sebesar 5 m/s adalah 30121.17 Watt. Effectiveness pada penggunaan 2 radiator dengan kecepatan udara sebesar 5 m/s adalah 0.65. Efisiensi fin yang terjadi pada kecepatan udara 5 m/s dengan menggunakan 2 radiator sebesar 0.93

  2. Heat transfer and pressure drop characteristics of nanofluids in a plate heat exchanger.

    Science.gov (United States)

    Kwon, Y H; Kim, D; Li, C G; Lee, J K; Hong, D S; Lee, J G; Lee, S H; Cho, Y H; Kim, S H

    2011-07-01

    In this paper, the heat transfer characteristics and pressure drop of the ZnO and Al2O3 nanofluids in a plate heat exchanger were studied. The experimental conditions were 100-500 Reynolds number and the respective volumetric flow rates. The working temperature of the heat exchanger was within 20-40 degrees C. The measured thermophysical properties, such as thermal conductivity and kinematic viscosity, were applied to the calculation of the convective heat transfer coefficient of the plate heat exchanger employing the ZnO and Al2O3 nanofluids made through a two-step method. According to the Reynolds number, the overall heat transfer coefficient for 6 vol% Al2O3 increased to 30% because at the given viscosity and density of the nanofluids, they did not have the same flow rates. At a given volumetric flow rate, however, the performance did not improve. After the nanofluids were placed in the plate heat exchanger, the experimental results pertaining to nanofluid efficiency seemed inauspicious.

  3. Experimental investigation on heat transfer and pressure drop of conical coil heat exchanger

    Directory of Open Access Journals (Sweden)

    Purandare Pramod S.

    2016-01-01

    Full Text Available The heat transfer and pressure drop analysis of conical coil heat exchanger with various tube diameters, fluid flow rates, and cone angles is presented in this paper. Fifteen coils of cone angles 180° (horizontal spiral, 135°, 90°, 45°, and 0° (vertical helical are fabricated and analysed with, same average coil diameter, and tube length, with three different tube diameters. The experimentation is carried out with hot and cold water of flow rate 10 to 100 L per hour (Reynolds range 500 to 5000, and 30 to 90 L per hour, respectively. The temperatures and pressure drop across the heat exchanger are recorded at different mass flow rates of cold and hot fluid. The various parameters: heat transfer coefficient, Nusselt number, effectiveness, and friction factor, are estimated using the temperature, mass flow rate, and pressure drop across the heat exchanger. The analysis indicates that, Nusselt number and friction factor are function of flow rate, tube diameter, cone angle, and curvature ratio. Increase in tube side flow rate increases Nusselt number, whereas it reduces with increase in shell side flow rate. Increase in cone angle and tube diameter, reduces Nusselt number. The effects of cone angle, tube diameter, and fluid flow rates on heat transfer and pressure drop characteristics are detailed in this paper. The empirical correlations are proposed to bring out the physics of the thermal aspects of the conical coil heat exchangers.

  4. Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

    Energy Technology Data Exchange (ETDEWEB)

    Shulman, Holly [Ceralink Incorporated, Troy, NY (United States); Ross, Nicole [Ceralink Incorporated, Troy, NY (United States)

    2015-10-30

    An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, green handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.

  5. Optimization of micro combined heat and power gas turbine by genetic algorithm

    OpenAIRE

    Yazdi Behnam Ahrar; Yazdi Behdad Ahrar; Ehyaei Mehdi Ali; Ahmadi Abolfazl

    2015-01-01

    In this paper, a comprehensive thermodynamic modeling and multi-objective optimization of a micro turbine cycle in combined heat and power generation, which provides 100KW of electric power. This CHP System is composed of air compressor, combustion chamber (CC), Air Preheater, Gas Turbine (GT) and a Heat Recovery Heat Exchanger. In this paper, at the first stage, the each part of the micro turbine cycle is modeled using thermodynamic laws. Next, with using ...

  6. Laboratory simulation of heat exchange for liquids with Pr > 1: Heat transfer

    Science.gov (United States)

    Belyaev, I. A.; Zakharova, O. D.; Krasnoshchekova, T. E.; Sviridov, V. G.; Sukomel, L. A.

    2016-02-01

    Liquid metals are promising heat transfer agents in new-generation nuclear power plants, such as fast-neutron reactors and hybrid tokamaks—fusion neutron sources (FNSs). We have been investigating hydrodynamics and heat exchange of liquid metals for many years, trying to reproduce the conditions close to those in fast reactors and fusion neutron sources. In the latter case, the liquid metal flow takes place in a strong magnetic field and strong thermal loads resulting in development of thermogravitational convection in the flow. In this case, quite dangerous regimes of magnetohydrodynamic (MHD) heat exchange not known earlier may occur that, in combination with other long-known regimes, for example, the growth of hydraulic drag in a strong magnetic field, make the possibility of creating a reliable FNS cooling system with a liquid metal heat carrier problematic. There exists a reasonable alternative to liquid metals in FNS, molten salts, namely, the melt of lithium and beryllium fluorides (Flibe) and the melt of fluorides of alkali metals (Flinak). Molten salts, however, are poorly studied media, and their application requires detailed scientific substantiation. We analyze the modern state of the art of studies in this field. Our contribution is to answer the following question: whether above-mentioned extremely dangerous regimes of MHD heat exchange detected in liquid metals can exist in molten salts. Experiments and numerical simulation were performed in order to answer this question. The experimental test facility represents a water circuit, since water (or water with additions for increasing its electrical conduction) is a convenient medium for laboratory simulation of salt heat exchange in FNS conditions. Local heat transfer coefficients along the heated tube, three-dimensional (along the length and in the cross section, including the viscous sublayer) fields of averaged temperature and temperature pulsations are studied. The probe method for measurements in

  7. Acoustic Optimization of Automotive Exhaust Heat Thermoelectric Generator

    Science.gov (United States)

    Su, C. Q.; Ye, B. Q.; Guo, X.; Hui, P.

    2012-06-01

    The potential for thermoelectric exhaust heat recovery in vehicles has been increasing with recent advances in the efficiency of thermoelectric generators (TEGs). This study analyzes the acoustic attenuation performance of exhaust-based TEGs. The acoustic characteristics of two different thermal designs of exhaust gas heat exchanger in TEGs are discussed in terms of transmission loss and acoustic insertion loss. GT-Power simulations and bench tests on a dynamometer with a high-performance production engine are carried out. Results indicate that the acoustic attenuation of TEGs could be determined and optimized. In addition, the feasibility of integration of exhaust-based TEGs and engine mufflers into the exhaust line is tested, which can help to reduce space and improve vehicle integration.

  8. Analysis of the flow structure and heat transfer in a vertical mantle heat exchanger

    DEFF Research Database (Denmark)

    Knudsen, Søren; Morrison, GL; Behnia, M

    2005-01-01

    initially mixed and initially stratified inner tank and mantle. The analysis of the heat transfer showed that the flow in the mantle near the inlet is mixed convection flow and that the heat transfer is dependent on the mantle inlet temperature relative to the core tank temperature at the mantle level. (C......The flow structure inside the inner tank and inside the mantle of a vertical mantle heat exchanger was investigated using a full-scale tank designed to facilitate flow visualisation. The flow structure and velocities in the inner tank and in the mantle were measured using a Particle Image...... Velocimetry (PIV) system. A Computational Fluid Dynamics (CFD) model of the vertical mantle heat exchanger was also developed for a detailed evaluation of the heat flux at the mantle wall and at the tank wall. The flow structure was evaluated for both high and low temperature incoming flows and for both...

  9. Heat Transfer Enhancement of Shell and Tube Heat Exchanger Using Conical Tapes.

    Directory of Open Access Journals (Sweden)

    Dhanraj S.Pimple

    2014-12-01

    Full Text Available This paper provides heat transfer and friction factor data for single -phase flow in a shell and tube heat exchanger fitted with a helical tape insert. In the double concentric tube heat exchanger, hot air was passed through the inner tube while the cold water was flowed through the annulus. The influences of the helical insert on heat transfer rate and friction factor were studied for counter flow, and Nusselt numbers and friction factor obtained were compared with previous data (Dittus 1930, Petukhov 1970, Moody 1944 for axial flows in the plain tube. The flow considered is in a low Reynolds number range between 2300 and 8800. A maximum percentage gain of 165% in heat transfer rate is obtained for using the helical insert in comparison with the plain tube.

  10. Horizontal Heat Exchanger Design and Analysis for Passive Heat Removal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, Karen

    2005-08-29

    This report describes a three-year project to investigate the major factors of horizontal heat exchanger performance in passive containment heat removal from a light water reactor following a design basis accident LOCA (Loss of Coolant Accident). The heat exchanger studied in this work may be used in advanced and innovative reactors, in which passive heat removal systems are adopted to improve safety and reliability The application of horizontal tube-bundle condensers to passive containment heat removal is new. In order to show the feasibility of horizontal heat exchangers for passive containment cooling, the following aspects were investigated: 1. the condensation heat transfer characteristics when the incoming fluid contains noncondensable gases 2. the effectiveness of condensate draining in the horizontal orientation 3. the conditions that may lead to unstable condenser operation or highly degraded performance 4. multi-tube behavior with the associated secondary-side effects This project consisted of two experimental investigations and analytical model development for incorporation into industry safety codes such as TRAC and RELAP. A physical understanding of the flow and heat transfer phenomena was obtained and reflected in the analysis models. Two gradute students (one funded by the program) and seven undergraduate students obtained research experience as a part of this program.

  11. Four K refrigerators with a new compact heat exchanger

    Science.gov (United States)

    Longsworth, R. C.; Steyert, W. A.

    1985-01-01

    Two refrigerators have been developed which have nominal cpacities of 0.25M and 0.5W at 4.2K. These use standard two stage Displex sup R expanders and compressors combined with a new compact heat exchanger which is concentric with the expander cylinder. These refrigerators can be used to cool superconducting electronic devices by direct attachment to the 4K heat station, or they can be plugged into the neck of a liquid helium superconducting magnet cryostat where they can cool the radiation shields and reliquefy helium.

  12. Solid-State Additive Manufacturing for Heat Exchangers

    Science.gov (United States)

    Norfolk, Mark; Johnson, Hilary

    2015-03-01

    Energy densities in devices are increasing across many industries including power generation, high power electronics, manufacturing, and automotive. Increasingly, there is a need for very high efficiency thermal management devices that can pull heat out of a small area at higher and higher rates. Metal additive manufacturing (AM) technologies have the promise of creating parts with complex internal geometries required for integral thermal management. However, this goal has not been met due to constraints in fusion-based metal 3D printers. This work presents a new strategy for metal AM of heat exchangers using an ultrasonic sheet lamination approach.

  13. Implications of fin profiles on overall performance and weight reduction of a fin and tube heat exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2017-01-01

    on a cross-flow type fin and tube heat exchanger design for a waste heat recovery application is conducted. The geometric profile of the fin is characterized by a dimensionless design variable named aspect ratio which is parametrically varied to obtain different profiles. Two cases, case-I, and case......Fin and tube heat exchangers are being used in several industrial applications by means of novel design and optimized performance. Improvements in geometric design may deliver energy efficient and cost-effective heat exchanger performance with reduced weight. In this paper, a systematic study...... design. Results show that the overall performance improves by approximately 6.76% and 17.33% with a reduction in net unit weight by approximately 27.58% and 6.82% on changing the aspect ratio from 1.0 to 0.1 in case-I and case-II, respectively. In addition, feasible fin profile for a waste heat recovery...

  14. Numerical computation of sapphire crystal growth using heat exchanger method

    Science.gov (United States)

    Lu, Chung-Wei; Chen, Jyh-Chen

    2001-05-01

    The finite element software FIDAP is employed to study the temperature and velocity distribution and the interface shape during a large sapphire crystal growth process using a heat exchanger method (HEM). In the present study, the energy input to the crucible by the radiation and convection inside the furnace and the energy output through the heat exchanger is modeled by the convection boundary conditions. The effects of the various growth parameters are studied. It is found that the contact angle is obtuse before the solid-melt interface touches the sidewall of the crucible. Therefore, hot spots always appear in this process. The maximum convexity decreases significantly when the cooling-zone radius (RC) increases. The maximum convexity also decreases significantly as the combined convection coefficient inside the furnace (hI) decreases.

  15. Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power

    Institute of Scientific and Technical Information of China (English)

    郭美茹; 朱启的; 孙志强; 周天; 周孑民

    2015-01-01

    To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles (ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area (UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15−363.15 K or 443.15−453.15 K, heptane is more suitable at 373.15−423.15 K, and R245ca is a good option at 483.15−503.15 K.

  16. Experimental investigation of shell-and-tube heat exchanger with a new type of baffles

    Science.gov (United States)

    Wang, Yingshuang; Liu, Zhichun; Huang, Suyi; Liu, Wei; Li, Weiwei

    2011-07-01

    A shell-and-tube heat exchanger with new type of baffles, is designed, fabricated and tested. The experimental investigation for the proposed model and the original segmental baffle heat exchanger are conducted. The operation performances of the two heat exchangers are also compared. The results suggest that, under the same conditions, the overall performance of the new model is 20-30% more efficient than that of the segmental baffle heat exchanger.

  17. Strategy for Synthesis of Flexible Heat Exchanger Networks Embedded with System Reliability Analysis

    Institute of Scientific and Technical Information of China (English)

    YI Dake; HAN Zhizhong; WANG Kefeng; YAO Pingjing

    2013-01-01

    System reliability can produce a strong influence on the performance of the heat exchanger network (HEN).In this paper,an optimization method with system reliability analysis for flexible HEN by genetic/simulated annealing algorithms (GA/SA) is presented.Initial flexible arrangements of HEN is received by pseudo-temperature enthalpy diagram.For determining system reliability of HEN,the connections of heat exchangers(HEXs) and independent subsystems in the HEN are analyzed by the connection sequence matrix(CSM),and the system reliability is measured by the independent subsystem including maximum number of HEXs in the HEN.As for the HEN that did not meet system reliability,HEN decoupling is applied and the independent subsystems in the HEN are changed by removing decoupling HEX,and thus the system reliability is elevated.After that,heat duty redistribution based on the relevant elements of the heat load loops and HEX areas are optimized in GA/SA.Then,the favorable network configuration,which matches both the most economical cost and system reliability criterion,is located.Moreover,particular features belonging to suitable decoupling HEX are extracted from calculations.Corresponding numerical example is presented to verify that the proposed strategy is effective to formulate optimal flexible HEN with system reliability measurement.

  18. Investigation into fouling factor in compact heat exchanger

    OpenAIRE

    Masoud Asadi; Ramin Haghighi Khoshkhoo

    2013-01-01

    Fouling problems cannot be avoided in many heat exchanger operations, and it is necessary to introduce defensive measures to minimize fouling and the cost of cleaning. The fouling control measures used during either design or operation must be subjected to a thorough economic analysis, taking into consideration all the costs of the fouling control measures and their projected benefits in reducing costs due to fouling. Under some conditions, nearly asymptotic fouling resistances can be obtaine...

  19. Negative Joule Heating in Ion-Exchange Membranes

    OpenAIRE

    Biesheuvel, P. M.; D. Brogioli; Hamelers, H. V. M.

    2014-01-01

    In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, t...

  20. All-metal, compact heat exchanger for space cryocoolers

    Science.gov (United States)

    Swift, Walter L.; Valenzuela, Javier; Sixsmith, Herbert

    1990-01-01

    This report describes the development of a high performance, all metal compact heat exchanger. The device is designed for use in a reverse Brayton cryogenic cooler which provides five watts of refrigeration at 70 K. The heat exchanger consists of a stainless steel tube concentrically assembled within a second stainless steel tube. Approximately 300 pairs of slotted copper disks and matching annular slotted copper plates are positioned along the centerline axis of the concentric tubes. Each of the disks and plates has approximately 1200 precise slots machined by means of a special electric discharge process. Positioning of the disk and plate pairs is accomplished by means of dimples in the surface of the tubes. Mechanical and thermal connections between the tubes and plate/disk pairs are made by solder joints. The heat exchanger assembly is 9 cm in diameter by 50 cm in length and has a mass of 10 kg. The predicted thermal effectiveness is greater than 0.985 at design conditions. Pressure loss at design conditions is less than 5 kPa in both fluid passages. Tests were performed on a subassembly of plates integrally soldered to two end headers. The measured thermal effectiveness of the test article exceeded predicted levels. Pressure losses were negligibly higher than predictions.