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Heat transfer can be intensified in shell-and-tube heat exchangers for improved heat transfer performance. Such intensification has been widely studied from the point of view of individual heat exchangers (HEs). The use of heat transfer enhancement in Process Integration has many benefits. First, enhanced heat exchangers require less heat transfer area for a given heat duty because of higher heat transfer coefficients. Second, the heat transfer capacity for the given HE can be increased without changing physical size of the exchanger. Third, the use of enhancement can reduce pumping requirement in some cases, as enhanced HE can achieve higher overall heat transfer coefficients with lower velocities, which may lead to lower friction losses. Using enhancement techniques has practical advantages in Heat Exchanger Network (HEN) retrofit, as it can avoid modification of the network structure. The implementation of enhancement is a relatively simple task that can be easily achieved within a normal maintenance period, allowing production losses to be kept to a minimum level and no civil engineering requirement. This chapter provides an introduction to the enhancement methods of commercial shell-and-tube heat exchangers and their engineering application. The key aspects of enhancing shell-and-tube heat exchangers in HEN retrofit are presented and illustrated with examples involving both energy saving and fouling considerations.

Heat exchangers are essential components of many systems and their use is extended to include various industrial, chemical, and automotive applications. Heat exchanger behavior affects the total performance of a thermal system. Enhancing this critical component leads to improving the system overall performance and thus its energy efficiency. Since a heat exchanger operates in conjunction with other process equipment, its evaluation under a transient condition is crucial. A transient response of heat exchangers is necessary to evaluate the exchanger performance when subjected to a change in its conditions. The scarcity of experimental data on a transient response of heat exchangers in general and minichannel exchangers in particular is the main motivation for this research. This work is an investigation of an experimental characterization of the transient response of a cross flow liquid-air heat exchanger subjected to step changes in liquid mass flow rate. Hot fluid mass flow rate step changes of 0.5, 0.8, 1.5, and 2.0 are considered and the liquid outlet temperature response time is presented. The results are compared with the limited experimental work from the literature. While the outlet temperatures of both fluids do not respond instantaneously to the step change in the primary fluid mass flow rate, the cold fluid exhibits a faster response time than that of the hot fluid. The step variation increases the Reynolds number which results in a longer hot fluid response time to reach the steady state. The outcome of this work is valuable in the design, selection, and analysis of heat exchangers. The experimental data provided in this work can be used to establish a database for future advances in research. It also provides an overview of the characteristic behavior of certain parameters such as fluid temperatures, response time, and residence time when the heat exchanger is subjected to a change in the hot fluid mass flow rate.

In respect of an efficient design of Organic Rankine Cycle (ORC) power plants, the heat exchange equipment plays an important role. Shell-and-tube heat exchangers are widely used in such energy conversion systems. The TEMA (Tubular Exchanger Manufacturers Association) E shell type with single-segmental baffles is a relatively simple and the most common design. For this configuration the shell-side heat transfer coefficient is in general determined by the Bell-Delaware method. However, in case of applications with low mean temperature differences like geothermal ORC systems, more advanced flow configurations are applied. In this work a TEMA NFN shell-and-tube heat exchanger with double-segmental baffles is analyzed for single-phase flow. For this design, the standard version of the Bell-Delaware method is not applicable. In this context, the Taborek version of the Bell-Delaware method is adapted to the specific heat exchanger design by adjusting the calculation methods for the main geometrical parameters like cross flow area, leakage areas and effective number of tubes in the overlapping region. The entire heat exchanger is simulated in DYMOLA 2015 FD01. Thereafter, the obtained temperature profiles are validated by real power plant data and deviate from operational data by up to −1.14 %. Subsequently, a novel correlation for an enhancement factor J x is developed. Due to the application to other shell-and-tube heat exchangers with double-segmental baffles, high accuracy is achieved. In addition, a heat exchanger baffle section is simulated in ANSYS FLUENT 15.0 in order to validate locally the novel adaption of the Taborek version of the Bell-Delaware method (main approach) by CFD simulations. The obtained heat transfer coefficients show a sufficient agreement.

In typical gas-to-liquid thermoelectric generators for waste heat recovery, the stream-wise gas temperature drop in the hot-side heat exchanger leads to the decrease of power output of the whole system. Denser fins are usually arranged on the downstream of the hot-side heat exchanger to improve the uniformity of temperature field and thus the total power output performance of thermoelectric generators when the steam-wise temperature drop is small, but it is not benificial when the steam-wise temperature drop is large. This work investigates the effect of configuration of winglet vortex generators on the performance of thermoelectric generator system. Three sets of hot-side heat exchangers, including a heat exchanger with smooth channel, a heat exchanger with uniform configuration of winglet vortex generators and a heat exchanger with non-uniform configuration of winglet vortex generators, are tested in a gas-to-liquid thermoelectric generators experimental system. The hot-side Reynolds number ranges from 3000 to 6400 and the hot-side inlet temperature is within 523–553 K. The experimental results show that the total and net power output of thermoelectric generator under matched load resistance with uniform heat exchanger can respectively outperform that with smooth heat exchanger by 97.5% and 77.7% in average, whereas that with non-uniform heat exchanger by 189.1% and 177.4% in average. Since the uniform and non-uniform heat exchangers have the same number but different configuration of winglet vortex generators, this kind of active cascade control of heat transfer enhancement elements is proved to be effective in improving the power output of thermoelectric generator system without increasing pumping power.

The aim of this study is to use a new configuration of porous media in a heat exchanger in continuous hydrothermal flow synthesis (CHFS) system to enhance the heat transfer and minimize the required length of the heat exchanger. For this purpose, numerous numerical simulations are performed to investigate performance of the system with porous media. First, the numerical simulation for the heat exchanger in CHFS system is validated by experimental data. Then, porous media is added to the system and six different thicknesses for the porous media are examined to obtain the optimum thickness, based on the minimum required length of the heat exchanger. Finally, by changing the flow rate and inlet temperature of the product as well as the cooling water flow rate, the minimum required length of the heat exchanger with porous media for various inlet conditions is assessed. The investigations indicate that using porous media with the proper thickness in the heat exchanger increases the cooling rate of the product by almost 40% and reduces the required length of the heat exchanger by approximately 35%. The results also illustrate that the most proper thickness of the porous media is approximately equal to 90% of the product tube's thickness. Results of this study lead to design a porous heat exchanger in CHFS system for various inlet conditions.

The heat recovery can substantially reduce energy consumption needful for heating or air conditioning of buildings. The aim of work is to develop a simple CAE method for rapid design and optimization of the dimensions of plate heat exchangers for heat recovery. Flow and heat transfer in an air-to-air recuperative counter-flow plate heat exchangers were investigated numerically. Pressure drop and effectiveness were evaluated as functions of inlet velocity for three sizes of real heat exchangers. Obtained data were analyzed, inlet/outlet cross-flow and middle counter-flow parts were investigated independently and data were substituted by suggested functions for Nusselt number and loss coefficients. These functions were used to illustrate the effect of heat exchanger dimensions. It proved that bigger heat exchangers provide higher effectiveness and lower pressure drop for the same flow rate, but also the heat transfer surface is larger. Derived equations which also take the effect of material thickness and plate pitch into account represent a useful tool for design and optimization of recuperative heat exchangers for use in HVAC systems.

This article is devoted to verification of VGHEs (Vertical Ground Heat Exchangers) used as a low-temperature energy source for heat pumps. The aim and objective of the study was to obtain practical knowledge of temperatures of rock mass and heat transfer fluids which affect the life cycle of the low temperature sources and the effectiveness of heat pump systems. The objective was also to gain knowledge of specific thermal energy and power extracted by these exchangers which are relevant to the evaluation of frequently used configurations of VGHEs. The results of the operational tests of two active boreholes with different arrangements, namely a single U exchanger (A), a double U exchanger (B) – and the reference (inactive) borehole (R). The tests were performed in the years 2012–2014 and involved 2 heating seasons and 2 exchanger stagnation periods. Results of the tests showed that exchanger B is more effective than exchanger A in terms of temperatures and particularly specific heat power and energies. The average specific thermal power in the heating periods were 23.11 W m −1 and 26.57 W m −1 for exchanger B and 16.88 W m −1 and 20.66 W m −1 for exchanger A. Total specific energies transferred from the massif during the heating periods were higher by 6.05 kWh m −1 and 6.94 kWh m −1 at exchanger B than at exchanger A.

Many commercial solar thermal power plants rely on indirect thermal storage systems in order to provide a stable and reliable power supply, where the working fluid is commonly thermal oil and the storage fluid is molten salt. The thermal oil - molten salt heat exchanger control strategies, to charge and discharge the thermal storage system, strongly affect the performance of the whole plant. Shell-and-tube heat exchangers are the most common type of heat exchangers used in these facilities. With the aim of developing advanced control strategies accurate and fast dynamic models of shell-and-tube heat exchangers are essential. For this reason, several shell-and-tube heat exchanger models with different degrees of complexity have been studied, analyzed and validated against experimental data from the CIEMAT-PSA molten salt test loop for thermal energy systems facility. Simulation results are compared in steady-state as well as transient predictions in order to determine the required complexity of the model to yield accurate results.

This study is purposed to estimate the pressure drop and thermal performance of three-dimensional heat exchanger units by the porous approximation, considering inertia effects. The full three-dimensional (3D) estimation of the thermal performance of the heat exchanger is very difficult because of the great complexity of the louvered-fin shape and lack of numerical resources. The volume grid used for this study was less than 10 million computational units. In order to verify the interpretation results, a compact heat exchanger having 9500 louver fins and 3D header tanks was tested experimentally and numerically. The simulation results for the air-side pressure drop agree well with the experimental result within 10 %, while the thermal effectiveness of the air was within 9.5 % of the experimental results. The present numerical method can be an effective tool to estimate the performance of multi-louver finned heat exchangers by using limited numerical resources.

Air-cooled heat exchangers are a main component in air-conditioning and heat pump systems and, therefore, a major research focus. Such heat exchangers, mainly of fin-and-tube and microchannel types...

In this paper, a mathematical model is developed to quantitatively evaluate the effect of flow maldistribution in a multi-channel heat exchanger. A computational fluid dynamics (CFD) technology is used to obtain the fluid distribution in the core of heat exchanger, taking into account the effects of gross passages, headers and distributors, etc. Based on the CFD simulation profile, a heat exchanger model is then developed. A parallel plate-fin heat exchanger with N flow passages is divided into N sub-exchangers when only one fluid is in maldistribution mode or 2N-1 sub-exchangers when both fluids are in nonuniformity modes to guarantee the uniform flow patterns in each sub-exchanger. Based on e-NTU theory, the effectiveness of the heat exchanger is calculated by modeling the heat exchanger as a parallel coupling of the sub-exchangers. The core pressure drop of the whole heat exchanger is taken as the average pressure drop of the sub-exchangers. The mathematical model combining with the achieved flow distribution was utilized to investigate the performance of the heat exchanger with conventional header configurations, a punched baffle header configuration and a quasi-S header configuration, respectively. Results indicated that a good synergy of flow rates for both cold and hot fluids in the adjacent sub-exchangers can effectively reduce effectiveness deterioration. The performance of the heat exchanger is improved by using the improved header configurations. And the performance with a quasi-S header configuration is the best. The proposed mathematical model provides a theoretical basis for multi-channel heat exchangers in solving the problem of flow maldistribution.

Functionalized solid amine-based temperature swing adsorption (TSA) processes have recently been proposed as a potential way to reduce the energy-penalty of post-combustion carbon capture processes. Thereby, multi-stage fluidized bed contactors with immersed heat exchanger surfaces and counter-current flow of solids and gas phase may solve the heat transfer challenge while maintaining the thermodynamic process requirements. Hence, the present work develops design requirements for TSA stages based on achievable heat transfer rates in bubbling fluidized beds. The considered particles are Geldart Type B. It is shown that the pressure drop of multi-stage fluidized bed TSA units for flue gas CO 2 capture is practically determined by the heat exchange requirement. Scalability, maintainability and durability of different heat exchanger geometries are considered. The net movement and mixing of particles within the bubbling bed stage must be maintained in spite of the immersed heat exchangers concerning possible dead zones in the area of the tube bundles. Comprehensive models are used to predict heat transfer coefficients for tubes immersed in fluidization. A heat transfer measurement test device for optimization of the heat exchanger geometry has been put into operation and heat exchange measurement results are compared to calculated heat transfer coefficients. It is shown that experimentally obtained heat transfer rates for single tubes are in good agreement with modeled values. A model proposed for Geldart A particles is used to estimate heat transfer rates for two particular tube bundles with a tube diameter of 25 mm and horizontal tube spacing of 2.2 and 2.8. It is shown that the calculated results represent heat transfer rates qualitatively and quantitatively for tube bundle heat exchangers immersed in Geldart Type B particle fluidized beds. Although this article has been motivated by heat exchange in TSA, it may be of interest for other applications concerned with heat transfer between bubbling fluidized beds and immersed heat exchanger surfaces.

In this paper, the new idea of the supercritical hydrogen–bleed air heat exchanger for future aircraft propulsion technology is investigated. The proposed heat exchanger will be located in the nacelle of commercial aircraft, and therefore is subjected to several geometrical constrains. At first, the initial geometry was proposed and then based on constrains and assumed operation conditions the main geometrical parameters and dimensions of the heat exchanger were calculated and optimized. The analyses were carried out by developing simple thermo-fluid 1D mathematical and numerical models of the heat exchanger, which were based on its geometrical features, directions of streams of hydrogen, and bleed air as well as on semi-empirical correlations for local Nusselt numbers and pressure drops for supercritical hydrogen and bleed air flows. The 1D model was partially validated using data from the experimental measurements. Then based on the obtained results, the final geometry of the supercritical hydrogen–bleed air heat exchanger was proposed.

An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs) with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and each sub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this method allows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties and the axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformity optimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field, because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicate that the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature difference of heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating condition with the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimization method proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.

Heat exchangers are widely used in almost all industrial activities. Turbulent promoters used in heat exchanger tubes are an effective way of enhancing the performance. This paper summarises various investigations using twisted tapes, wire coil ribs, baffles, and swirl flow generators. The main objective of this paper is to review various studies, in which different obstacle roughness elements are used to enhance the rate of heat transfer in the heat exchanger tubes. It has been found that a lot of experimental and analytical studies reported in the literature. On the basis of correlations developed by various investigators an attempt has been made to compare the thermal hydraulic performance of obstacles in heat exchanger tubes. In this work, a comparative study is also carried out to select the best obstacle roughness shapes for higher heat transfer rate and low pressure drop losses.

The present work focuses on a three-dimensional CFD approach to predict the performance of various heat exchangers in conjunction with non-isothermal transitional flows for motorsport applications. The objective of this study is to determine the heat transfer, pressure drop and inhomogeneous flow behaviour for distinct heat exchangers to identify an optimum configuration for the charge air cooler, water and oil radiators placed in the sidepods of a formula one (F1) car. Therefore, a comprehensive analysis of various heat exchanger configurations has been carried out in this work. In order to assess the reliability of the obtained results, a mesh sensitivity study along with additional parametric investigations have been performed to provide numerical parameters predicting accurately (a) the heat transfer rate at the fluid-solid interface and (b) the sporadic separation. As a result of the performed validation procedure in this study, the aerodynamic- and thermal boundary layer development along with the convective characteristics of the air flow have been captured accurately near to the heated surface. The characterization of a heat exchanger core and a core configuration in a closed domain is also possible with this procedure. The presented three-dimensional CFD approach could overcome the difficulties of macroscopic heat exchanger and porous media methods for F1 applications, because it can be used to predict the heat transfer and pressure drop related to the mass flow rate correlation curves. The contribution of fins to the total heat transfer rate has been predicted theoretically, and application benchmark test cases have been presented to analyze five different heat exchanger configurations in accordance with the 2014 formula one technical regulations. The numerical data extracted directly from three-dimensional CFD simulations can be used in the sidepod design process of the external cooling system of F1 engines.

Renewable energies are gaining importance due to the steadily increasing scarcity of fossil fuels, the ongoing climate change and last but not least the risks which accompany the use of nuclear power. In this growing market, solar thermal power plants offer a centralized, potentially load following electricity production. To serve this need, the integration of thermal energy storage systems is essential. The Moving Bed Heat Exchanger MBHX storage concept for CSP systems using sensible heat transfer medium aims at using a low cost solid storage media. This concept requires intermediate bulk cycles to transfer heat between the solar field and the storage material (the bulk). Heat Transfer Fluids (HTF) such as synthetic oils (mobiltherm 603) are typically used. In this work, granular materials such as sand and rocks are studied to present an additional HTF to represent an efficient and cost-effective alternative. Low cost solid particulates can store and transport heat at temperatures over 1000°C. For the purpose of heat recovery, a moving bed heat exchanger (MBHX) is applied and tested. In this study, the dense granular mass is gravity-driven through a heat exchanger. The performance of the MBHX with the utilization of Sand, Basalt, and a Mixture of Sand and Basalt as a granular material was experimentally investigated. It is found that the effectiveness of the MBHX using a mixture of 50% sand and 50% basalt improved by 30% compared to using sand alone.

The developments and the enhancements in all the heat transfer equipments are mainly purposed for energy savings and savings in projects capital investment, through reducing the costs (energy or material). The better heat exchanger is one that transfer's high heat rate at low pumping power with a minimum cost. The spent of money for the research and development in corrugated plate heat exchangers, in last decades, from some companies, offered different and versatile types and models of that heat exchanger. In the current study I made a focus on researcher's efforts in research and developments for corrugated plate heat exchanger. This type of heat exchangers is widely used for different engineering fields and applications. Research reactors represent one of the important engineering fields that extensively use corrugated plate heat exchangers due to their simplicity in assembly/disassembly and their easy maintainability. The corrugated plate heat exchanger has a great flexibility than the other types of heat exchangers; both its heat transfer area and its cooling flow could be increased or decreased easily, so; it is commonly used for enlargement and upgrading works. The current revision incorporated different topics like; the plate heat exchanger structure, thermal performance, heat transfer enhancement mechanisms as well as plate heat exchanger advantages and limitations. The corrugated plate heat exchanger works efficiently in both single phase and two phase flow, while the two phase flow region still needs a lot of research work. Also; the corrugated plate heat exchanger thermal performance and pressure drop behaviours when using nano-fluids were discussed in the current revision.

Our society has rapidly developed in recent years, with high lands being increasingly utilized; leading to a greater application of the heat exchanger due to the need to deal with low pressure environments of the higher altitudes. Accordingly, the variables affecting the heat exchanger’s performance under low pressure environments have attracted much needed attention. This paper focuses on an experiment where a low-pressure wind tunnel test-bed was established to test the heat transfer and flow characteristics of a plate-fin heat exchanger. This paper then compares and analyzes the experimental data to look at what determines changes in the heat exchanger’s characteristics under low pressure environments. Finally, this paper examines the results which indicate that the heat exchanger’s performance is closely affected by low pressure environments in that the degree of heat transfer is very much dependent on changes in the cooling medium properties, boundary layer as well as the synergy between velocity and temperature fields, all of which are variables present with changing pressures in an environment. This paper will simultaneously discuss the methods of theoretical analysis and simulation, which were used to explore the mechanism of how low-pressure settings worked on the heat transfer and flow characteristics of heat exchangers.

A plate heat exchanger is a type of heat exchangers that provides more surface area for heat transfer between two fluids. Plate heat exchangers are widely used for heat transfer applications in the industry. In addition, they are now widely used in many applications such as food processing, chemical reaction processes, heating and cooling applications in sectors such as petroleum. However, the design of plate heat exchangers is complicated by the large number of variables and geometries that affect its performance. A better heat exchanger design is to achieve a high heat transfer rate at low pumping power with low cost. In this study, the focus is on the research and development efforts of different plate materials, various fluid types, their flow regimes and the plate grooving angles on plate heat exchanger performance. For this purpose, the Computational Fluid Dynamics (CFD) is used. The results show that the heat efficiency is the best performing heat exchanger that can be designed as parallel- and counter-flow, geothermal fluid, titanium plate and 60° groove angle from the point of view.

The paper presents a physical and mathematical model for calculating the air-to-air heat exchanger with periodically changing direction of the air flow. It accounts for vaporization and condensation on the channel walls of the heat exchange matrix with regular structure as well as possible formation of water fog directly in the air flow. The model can be used to analyze the influence of operating parameters, the geometric dimensions of the channels and properties of the used materials on the work efficiency of the heat exchanger. The results of calculations of the influence of indoor air humidity on heat and moisture transfer processes in the regenerative heat exchanger are provided. Sensible and latent efficiency of the regenerative heat exchanger as well as their dependence on relative humidity of indoor air are determined. The relationship between the outdoor air temperature and relative humidity of indoor air, at which ice formation begins in the channels of the heat exchange matrix, is found.

Plate heat exchanger can obtain higher thermal performance because of its advantages in high heat transfer coefficient, small scale, and can realize pure counter current flow. It has been widely applied in HVAC industry. In this paper, the numerical research of plate heat exchanger in solar heating system has been proposed. Aimed at the type of herringbone corrugated plate which has better thermal performance and been widely used, the three dimensional model is established by Gambit software. Using FLUENT software for numerical calculation, by studying the effect of corrugated inclination angle, corrugated depth, corrugated spacing and inlet velocity of heat exchanger on internal temperature, pressure, velocity distributions of domains, the relationship between the above parameters and the Nusselt Number and the pressure drop was obtained by simulation data. Heat transfer coefficient and pressure drop correlations used to measure the overall performance of the heat exchanger. The result shows that the optimal structure parameters is corrugated angle 60°, corrugated depth 4 mm and corrugated spacing 16 mm.

The Earth upper layer low-potential heat energy extraction and using technologies are considered in the paper. The decentralized heating schemes with borehole heat exchangers and geothermal heat pumps are described. The ecological and environmental advantages and limitations for common borehole heat exchanger constructions are specified. The promising borehole heat exchanger construction based on ground thermosyphon heat pipes is emphasized. The thermal properties of the ground thermosyphon working fluids and the results of experimental tests are described in the paper. The boreholes heat exchanger construction doesn’t require pump and may be used for decentralized heating facilities with small installed capacity.

In this paper, steady state sensible performance analysis on multi pass parallel cross flow exchanger was considered. The inputs to the heat exchanger were described through meaningful physically significant parameters such as number of transfer units, capacity rate ratio and dimensionless input temperature. The inputs to the heat exchager were varied systematically and a parametric study was conducted to determine the thermal performance at each individual pass of the heat exchanger. Heat exchanger’s thermal performance was described through the discharge temperatures that were expressed in a dimensionless form. The results from the study were presented in the form of performance tables. The performance tables employed meaningful and industry recognized dimensionless input parameters and the heat exchanger‘s performance was described through dimensionless discharge temperatures at every pass of the heat exchanger. The developed performance tables shall serve two critical aspects. First, it will help the heat exchanger designers to readily choose an optimum heat exchanger. An undersized heat exchanger shall not deliver the requirements and likewise an oversized heat exchanger shall add unnecessary weight and cost. This aspect was clearly observed in this study as indefinetly increasing the number of transfer units (or surface area) beyond a threshold value didn’t enhance the heat transfer. By employing the performance tables as a guide, the heat exchanger designers can quickly ascertain the performance of the heat exchanger without having to perform simulations and/or lengthy calculations. Second, during operational phase of the heat exchanger, the performance tables can be used to understand the performance variation of the heat exchanger with respect to mass flow rates and/or can help the engineers to choose appropriate mass flow rates for the required heat transfer. The highest heat exchanger performance was observed at the lowest capacity rate ratio and likewise the lowest heat exchanger performance was observed at the highest capacity rate ratio. In-addition, during the operational phase, the performance tables can help to detect an underperforming heat exchanger and can help the engineers to schedule maintenance activity on the heat exchanger equipment.

Heat exchangers are devices in which heat is transferred from one fluid to another fluid as a result of temperature difference. Heat exchanger presented in the current paper in which inside the tubes flows water, but outside the tubes flows air aims to enable cooling of circulating water, which serves to cool the engine of a machine. Such exchangers find application in the automotive industry as well as heating and cooling equipment and HVAC systems etc. The surface of the heat exchanger by the air side always tends to be much larger using surface fins in order to facilitate equalization of thermal resistance for both sides of the heat exchanger, because the rate of transmission of heat from the water side is much greater. Furthermore, the paper will present analytical and experimental studies involved for determination of performance of plate-fin heat exchanger for various flows of working fluids in order to get the highest values of performances i.e.: overall heat transfer coefficient U, efficiency of heat exchanger e, maximal and real heat transferred, pressure drop, air velocity and Reynolds number from the air side of heat exchanger etc. The present scientific paper is based on the fact that from the experimental model made for laboratory conditions, conclusions are derived that can be used during installation of such heat exchanger on certain machines in order to predict their performance.

Compact heat exchangers are one of the most critical components of many cryogenic components; they are characterized by a high heat transfer surface area per unit volume of the exchanger. The heat exchangers having surface area density (β) greater than 700 m2/m3 in either one or more sides of two-stream or multi-stream heat exchanger is called as a compact heat exchanger. A compact heat exchanger which is widely used in automobile, cryogenics, space application and chemical industries. This paper presents the study of CH4 type compact heat exchanger is designed to get that parameter like heat transfer coefficient, effectiveness, and to reduce the size of the heat exchanger as compact as possible.all this Experimentation we can conclude that the size of Heat exchanger can be effectively reduced. The proposed Geometry of CH4 Type Compact Heat Exchanger is fabricated and tested. The compact heat exchanger is a water to water, or liquid to liquid compact size heat exchanger, which is very compact in size as compare to the existing CHE.

A helical coil tube heat exchanger is generally applied in industrial applications due to its compact structure, larger heat transfer area and higher heat transfer capability etc. The importance of compact heat exchangers has been recognized in many industrial applications ranging from chemical and food industries, power production, electronics, environmental engineering, manufacturing industry, air conditioning, waste heat recovery, cryogenic processes and space applications for the last six decades. However, flow and helical coils are extensively used as heat exchangers and reactors due to higher heat and mass transfer coefficients, narrow residence time distributions and compact structure.

This article presents design analysis of a fuel oil preheater. The preheater is a concentric tube heat exchanger where the fuel oil is on the tube-side and the heating medium flows in the annular space. Two situations were addressed in this study. In the first case, an analytical model was developed where the required heat exchanger length, diameter and the fluid velocity were determined for a given heat transfer duty and for an allowable pressure loss. A detailed study was conducted by individually varying parameters such as pressure loss, preheater discharge temperature, and mass flow rate of the fuel oil. In each instance their influence on the predicted design of the heat exchanger was investigated. In the second case, an optimization strategy was proposed for a certain heat transfer duty. The heat exchanger dimensions and the fluid flow rate were selected such that the annual operating cost of the heat exchanger was minimized. In addition, a detailed study was conducted to understand the tota...

This paper applies CFD modelling and numerical calculations to predict the thermal performance of a cross flow heat pipe based heat exchanger. The heat exchanger under study transfers heat from air to water and it is equipped with six water-charged wickless heat pipes, with a single-pass flow pattern on the air side (evaporator) and two flow passes on the water side (condenser). For the purpose of CFD modelling, the heat pipes were considered as solid devices of a known thermal conductivity which was estimated by experiments conducted on the exact same heat pipe configuration under an entire testing range. The CFD results were compared with the experimental and the numerical results and it was found that the modelling predictions are within 10% of the experimental results. The European Development Fund and Econotherm (UK) Limited.

This study was realized to eliminate the problems that occurred in Kizildere geothermal field Saraykoy district heating systems. Geothermal fluid which is used in heating systems causes surface fouling and scaling shaped as intense corrosion and buffer brush over the plate type heat exchanger which transfers heat. This formation complicates the transfer of heat and fluid permeability. In order to eliminate this situation, the heat exchangers are cleaned while being stopped or a spare part is used. This causes an interruption in heating and increases the operation costs. In order to solve this problem, an experimental study was carried out about the determination of usability of liquid/solid fluidized bed heat exchanger instead of the plate type heat exchanger and optimum operation conditions. Silica sand as solid particles (2–4 mm), marble (2–5) and quartz (1.2–2.5 mm) sized materials were used in order to determine the advantages of preventing the increase of heat exchanger which will be provided by a liquid/solid fluidized bed heat exchange mechanism or a decrease of scaling. In this research, the usage of a liquid/solid fluidized bed heat exchanger (FBHE) instead of the plate type heat exchanger was considered proper and the best particle type is silica sand, the thermal performance increased 14.9% compared to the plate type heat exchanger in the same operation conditions. As an addition to the literature, (Rep)cr value was determined in order to determine the particle flow conditions in bed and corresponding correlations were derived for the heat transfer greatness. The results obtained from the research were submitted according to the particle type in graphical and correlation situations.

The intermediate fluid vaporizer has wide applications in the regasification of LNG (liquefied natural gas). The heat exchanger performance is one of the main contributors to the thermodynamic and cost effectiveness of the entire LNG regasification system. Within the paper, the authors discuss a new concept for a compact heat exchanger with a micro-cellular structure medium to minimize volume and mass and to increase thermal efficiency. Numerical calculations have been conducted to design a metal-foam filled plate heat exchanger and a shell-and-tube heat exchanger using published experimental correlations. The geometry of both heat exchangers was optimized using the conditions of thermolators in LNG regasification systems. The heat transfer and pressure drop performance was predicted to compare the heat exchangers. The results show that the metal-foam plate heat exchanger has the best performance at different channel heights and mass flow rates of fluid. In the optimized configurations, the metal-foam plate heat exchanger has a higher heat transfer rate and lower pressure drop than the shell-and-tube heat exchanger as the mass flow rate of natural gas is increased.

Highly-efficient heat exchange is expected for the falling-film-type heat exchanger handled in this study by utilizing a falling liquid film, etc. The heat medium is flowed inside the heat exchanger tube. In contrast, the falling film is flowed outside the heat exchanger tube, thereby exchanging heat. In the previous study, considering the basic heat transfer characteristic of the falling-film-type heat exchanger, the design equation was developed in the limited extent. In this study, focusing on the flow condition in a heat exchanger tube of the falling-film-type heat exchanger, various shafts with screw blade were inserted in a single heat exchanger tube and it was evaluated how the pitch and height of screw and the flow rate of cooling water would give an effect on the heat exchange performance. Additionally, the heat transfer coefficient and the overall heat transfer coefficient of the falling-film-type heat exchanger were logically calculated, and then a theoretical value and an experimental value were compared and evaluated. As a result, it was clarified that the heat exchange performance of the falling-film-type heat exchanger was improved by inserting the shaft with screw blade, and theoretical and experimental values were roughly matched.

In studies using computational fluid dynamics software, very often a uniform air stream is applied as inlet boundary condition of a heat exchanger. In actual applications, however, the inlet flow conditions are not uniform. Therefore, the effect of non-uniformities on the thermal performance is characterized in a wind tunnel for a commercially available plate water/air heat exchanger. Three non-uniform flow conditions are investigated. The heat exchanger is 275 mm wide and 295 mm high. Three non-uniformities are created by placing a plate 10 cm upstream of the heat exchanger: the first one covers the right-hand side of the heat exchanger, the second one covers the top half of the heat exchanger and the last obstruction consists of a circular hole of 150 mm diameter in the middle of a plate. Only the circular obstruction has a significant influence on the heat transfer rate: the external convective resistance is up to 25% higher compared to the uniform case. The measurement results presented in this study can be used by other researchers to validate numerical simulations with non-uniform inlet conditions.

There has been increased attention on various types of plate heat exchangers because of their high efficiency and compactness. This article presents an investigation of heat transfer and fluid flow performance of a novel plate heat exchanger based on numeric studies and experimental tests. Parameters of the novel plate heat exchanger are analyzed and discussed. The thermo-hydraulic transfer performance of different plate heat exchangers is comprehensively analyzed using the exergy and entransy principle. The results indicate that the novel plate heat exchanger has better thermo-hydraulic transfer performance than the smooth plate heat exchanger. The result of this study provides a paradigm for the optimal design of plate heat exchangers.

For efficient utilization of a limited geothermal resource in practical projects, the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger, with a variation of flowrate of R245fa. The influence of working fluid flowrate on a 500W ORC system was investigated. Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined. Therefore, for the ORC systems, optimal working fluid flowrate should be controlled. Using different temperature hot water as the heat source, it is found that the optimal flowrate increases by 6-10 L/h with 5 °C increment of hot water inlet temperature. During experiment, lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation. It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation. To avoid this phenomenon, the flow area of plate heat exchanger should be larger than the designed one. Alternatively, installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution.

The experimental and numerical investigations of the triple concentric-tube heat exchanger are presented with particular reference to double tube heat exchanger. The purpose is to present a clear view on the thermo-fluid characteristics of this type of heat exchangers with different key design parameters leading to design optimization. Three fluids being considered are chilled water in inner tube, hot water in inner annulus, and normal tap water in outer annulus. Numerical CFD model is developed using a finite volume discretization method. The numerical model is validated and then extended to cover more extra design parameters. Four flow patterns are conducted of counter current, co-current, counter current with co-current and co-current with counter current flow. Correlations of Nusselt number, friction factor and heat exchanger effectiveness with the dimensionless design parameters are also presented. The triple tube heat exchanger contributes higher heat exchanger effectiveness and more energy saving compared with double tube heat exchanger per unit length.

Particle-based concentrating solar power (CSP) plants have been proposed to increase operating temperature for integration with higher efficiency power cycles using supercritical carbon dioxide (sCO2). The majority of research to date has focused on the development of high-efficiency and high-temperature particle solar thermal receivers. However, system realization will require the design of a particle/sCO2 heat exchanger as well for delivering thermal energy to the power-cycle working fluid. Recent work has identified moving packed-bed heat exchangers as low-cost alternatives to fluidized-bed heat exchangers, which require additional pumps to fluidize the particles and recuperators to capture the lost heat. However, the reduced heat transfer between the particles and the walls of moving packed-bed heat exchangers, compared to fluidized beds, causes concern with adequately sizing components to meet the thermal duty. Models of moving packed-bed heat exchangers are not currently capable of exploring the design trade-offs in particle size, operating temperature, and residence time. The present work provides a predictive numerical model based on literature correlations capable of designing moving packed-bed heat exchangers as well as investigating the effects of particle size, operating temperature, and particle velocity (residence time). Furthermore, the development of a reliable design tool for moving packed-bed heat exchangers must be validated by predicting experimental results in the operating regime of interest. An experimental system is designed to provide the data necessary for model validation and/or to identify where deficiencies or new constitutive relations are needed.

The design and performance testing of a single-phase, flat plate, manifold microchannel heat exchanger with water as the working fluid are discussed in this paper. The aim of this study was to explore the use of manifolding of microchannels for performance enhancement of plate heat exchangers for single-phase, low heat flux (process type) applications operating in a counter flow configuration. The paper discusses the design of the heat exchanger, followed by the experimental testing and numerical simulation results. The experimental tests reveal that the heat exchanger is capable of delivering an overall heat transfer coefficient of close to 20,000 W/m2K at flow rates as low as 20 g/s (corresponding to a microchannel Reynolds number of 30) and a pressure drop per length value of 5.85 bar/m. The experimental results also are compared with established counter flow heat exchanger e-NTU correlations to verify counter flow performance. Further, numerical simulation results for a single unit cell of the same geometry, which show reasonable agreement with the experimental results, are also described in this paper. The current work demonstrates successful use of microgrooves/microchannels for performance enhancement of plate heat exchangers for diverse industrial applications, including the refrigeration/air conditioning, process, and power production sectors.

In this article, the performance and applications of a Spiral Plate Heat Exchanger are demonstrated. Also, governing equation of heat transfer phenomena in such heat exchangers is discussed. Regarding the governing equations, a LAB-sized model of this type of heat exchanger was designed and constructed. Galvanized Iron sheets were used as the heat transfer surfaces. Two Galvanized Iron sheets were rolled together around a central core and, as a result, two separated channels were made. Also, a predesign simulation of the heat exchanger was done using the Fluent software to predict the performance of the heat exchanger. First the geometry was made using Gambit software environment then the model was analyzed through Fluent. Because of less fouling, easier cleaning and high heat transfer coefficient, Spiral Heat Exchanger is a good alternative to the other types of heat exchangers, especially when it’s going to handle high fouling flows or highly viscous fluids. Low fouling rate of the heat exchanger, reduces the need of cleaning and therefore the out of service will be decreased. In the constructed heat exchanger, Nusselt number increases as the mass flow rate increases. Average Nusselt number is about 100 that is very good.

The results of experimental investigation and physical–mathematical modeling of heat transfer in the air-to-air heat exchanger with a periodic change in the airflow direction for room ventilation are presented in the paper. Based on the joint analysis of heat balances in the airflow and in material of heat exchanger packing, the model for calculating heat exchanger operation was suggested. The results of calculations by the suggested model are in satisfactory agreement with the experimental data. The dependence of operation efficiency of heat exchanger on air flow rate is determined theoretically and experimentally; it is found out that operation efficiency of the device increases linearly with decreasing flow rate. It is shown that a change in the ratio of flow rates of opposite airflows through the heat exchanger can regulate the temperature of air, supplied into a room. The possibility to use this model for optimization of operation and construction parameters of the heat exchanger is shown.