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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.

Moving bed heat exchangers have been the economic alternatives for the granular flow in industries. To predict the heat transfer coefficients, a better understanding is required of the contact resistance (1/hws) and the penetration resistance (1/hso). In this work, the heat transfer coefficients were simulated using the finite volume method to investigate these resistances in both ordered and random packing sphere particles. It was found that, the 1/hws is determined by the effective thermal conductivity in the wall region, of which the thickness is around 3/22 particle diameters. Moreover, the 1/hso is affected by the heat capacity, thermal conductivities and particulate structures. The effect is reflected by two modified equivalent heat absorption coefficients (1/p1 and 1/p3) in granular flows. Generally, p1 is smaller in the ordered structure because the peak local solid fraction is higher, while p3 is smaller in the random structure due to the lower average porosity.

Heat transfer in gravity-driven granular flow has been encountered in many industrial processes, such as waste heat recovery and concentrated solar power. To understand more about Moving Bed Heat Exchanger (MBHE) applied in this field, numerical simulation was carried out for the characteristics of granular flow near different surfaces through discrete element method (DEM). In this paper, both the performances of particles motion and heat transfer were investigated. It’s found that, even though the macroscopic granular flow is similar to fluid, there is still obvious discrete nature partly. The fluctuations of parameters in granular flow are inevitable which is more obvious in the circular tube cases. A special phenomenon, where competition motion is found, is resulted from discrete nature of particles. In terms of heat transfer, overall heat transfer coefficients for plate are higher than that of tube owing to better contact between particles and wall. However, due to competition motion, particles in high temperature tend to contact the tube, which is beneficial to heat transfer in some local zones. The heat transfer characteristics above will also affect the temperature distribution near the outlet of different geometries.

A number of analytical solutions for moving bed heat exchangers (MBHEs) have been recently obtained by means of Laplace transforms. In this work, an alternative method for obtaining the analytical ...

Moving bed heat exchangers take important part in terms of extracting heat from granular materials. Circular tube is main part of heat exchanger in most studies and implements. Two heat transfer deterioration zone for circular tubes in granular flow is found and results in a low heat transfer coefficient. Elliptic tubes receive increase attention recent years for their better heat transfer performance for fluid. In this work numerical investigation based on DEM has been produced to obtain heat transfer performance of elliptic tubes in granular flow with different axis ratio. The result shows that elliptic tubes with axis ratio from 1.2 to 2.0 have a narrower area of heat transfer deterioration in granular flow and consequently a higher effective heat transfer coefficient from than circular tube (axis ratio =1.0) with the same long axis.

A fluidized bed adsorption (FLBA) process with internal heat integration is considered an energy-efficient method for large-scale CO2 capture. Herein, we propose a pseudo counter-current FLBA process for post-combustion CO2 capture as a proof-of-concept based on a rationally designed moving bed heat exchanger by incorporating the internal heat integration concept of the conventional amine scrubbing CO2 capture process. The proposed FLBA process consists of an adsorption bed, desorption bed, and moving bed heat exchangers for cooling and heating the solid sorbent. The design of the proposed FLBA process enables internal heat integration by recovering sensible heat from the cooling process. Furthermore, by installing multiple adsorption processes, the pseudo counter-current operation in the adsorption bed enhances the CO2 cyclic capacity of the amine-functionalized solid sorbent with high CO2 recovery. The proposed process complements the two weaknesses of FLBA, namely, large sensible heat and low cyclic capacity of the sorbent. The energy analysis, based on rigorous mathematical modeling, estimates that the energy demand of the optimized FLBA using SiO2/0.37 EB-PEI is approximately 258.6 kWh/t-CO2 with 45% sensible heat recovery. This low energy demand is comparable to that of the most mature amine-based absorption process (271 kWh/t-CO2) owing to the effect of internal heat integration, supporting the feasibility of the FLBA process for post-combustion CO2 capture.

In order to investigate the heat transfer uniformity of fluidized bed heat exchangers (FBHEs), a series of experimental tests were carried out in a commercial 300 MW CFB boiler. The test results indicate that there is a good linear correspondence between the FBHEs conical valve openings and circulating ash flow rate, the average heat transfer coefficient of different heat exchangers takes on a monotonically increasing trend with the increase of the boiler loads. Moreover, there is a non-uniform heat transfer process between the different measuring points under the same load as well as the different loads for the same measuring points, the heat absorption proportion of two FBHEs (71# and 72#) on the left side is larger than that of two FBHEs (73# and 74#) on the right side of the furnace, there is a non-uniform heat transfer phenomena in the symmetrical arrangement of four FBHEs, the heating surface arrangement in the FBHEs must be adjusted from snake tube perpendicular to the ash flow direction to parallel to ash flow direction, the test results can provide a good reference for the optimized design and operation of 600 MW supercritical CFB boiler with the FBHEs in the future.

Air flow mal-distribution has been identified as one of the causes for performance degradation of air-to-refrigerant heat exchangers. The accurate prediction of such a non-uniform air flow profile requires full heat exchanger simulations using Computational Fluid Dynamics (CFD) models which are often much more computationally expensive than traditional lumped parameters or finite volume based heat exchanger models. The high computational cost of CFD makes it difficult to comprehensively study the effect of multiple parameters impacting the air flow distribution and the heat exchanger performance. In this study, an integrated CFD-segmented heat exchanger model based on a momentum resistance model is developed that is computationally efficient and accurate. The CFD simulation process is fully automated using script based open-source CFD code, OpenFOAM. The momentum resistance-based CFD model is validated against Particle Image Velocimetry (PIV) data and parametric studies are performed to investigate the influence of heat exchanger geometries (HX angle, HX depth, HX height and fin type) and air flow rate on the air flow mal-distribution under dry operating condition. In addition, an approach to scale the velocity profiles using multivariate linear interpolation is proposed. The interpolation model can further accelerate the simulation speed without compromising the accuracy compared to the CFD model.

The objective of this paper is to review the different techniques, which have been used to enhance the heat transfer rate in heat exchanger devices such as solar air heater, cooling blades of turbine and so on using single phase heat transfer fluids. The results of recent published articles with the development of new technologies such as Electrohydrodynamic (EHD) and Magnetohydrodynamics (MHD) are also included. Enhancement of heat transfer in heat exchanger can achieved by means of several techniques. These techniques are grouped into the active and passive method. In the active methods, system need some external power, however, passive method utilize surface modification either on heated surface or insertion of swirl devices in the flow field. Active methods are very complex because of external power supply, although these methods have great potential and can control thermally. Passive methods include artificial roughness, extended surface, winglets, insertion of swirl devices in the flow which alters the flow pattern causes to disturb the thermal boundary layer, and consequently high heat transfer. Passive methods are dominant over active methods because its can easily employed in existing heat exchangers. In this paper, an effort has been made to categorize the active and passive methods and review the various heat transfer techniques applied in heat exchangers. Important results have been listed for ready reference. It has been concluded that either active or passive methods have been employed alone. Based on literature, a combined method have also been recommended which include both active and passive methods.

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.

An analytical solution is obtained for an energy model of a moving bed heat exchanger (MBHE) that includes axial heat conduction, subject to an external fluid at constant temperature. The problem formulation and nondimensionalization of the steady-state energy equations are presented for a parallel-plate system. The analytical solution is verified by examining it at the limit where axial heat conduction is neglected, and shown to simplify to expressions in the literature. The analytical solution is also compared to the results of a numerical solution under various conditions, and found to be in agreement. Finally, the solution is used to quantify the importance of axial heat conduction in a given MBHE, and the results are summarized in the form of error maps.

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...

The present paper focuses on the development steps of heat exchangers dedicated to single room ventilation unit with heat recovery (SRVHR) by proposing a numerical approach. A methodology is suggested in order to determine the best trade-off between hydraulic and thermal performance given a specific geometry. The methodology consists in a mapping of the coefficient of performance (COP) of the unit. The latter is defined as the ratio between recovered heat and the fan energy use, given a specific indoor/outdoor temperature difference. However, the energy performance should not be the only criterion to be taken into account in the frame of the design steps of a heat recovery exchanger: technical, economic and acoustic aspects should also be considered. This numerical methodology is illustrated by means of a real example of a newly developed heat exchanger dedicated to a SRVHR. The optimization is first performed while using a semi-empirical model (based on the use of correlations and on a spatial division of the studied heat exchanger). The semi-empirical model allows for the creation of a COP map in order to identify the most effective geometry parameters for the heat exchanger. The decision concerning the final geometry is made accounting for the so-called technical, economic and acoustic considerations. A discussion on some parameters needed for the COP establishment is also proposed.

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.

The current technical brief is to analytically solve the coupled energy equations governing the thermal phenomenon of particulate solids and cooling fluid present inside moving bed heat exchangers constructed via a parallel plate system. The prime concern is to analytically evaluate the cooling effects of a heat sink (absorbent) placed within the media on the particulate and fluid and hence to obtain the relevant temperature fields for the latter. In the absence of such a source term, the solutions collapse onto the recent literature. Results clearly demonstrate how an effective cooling can be achieved with a heat sink mounted on industrial moving bed heat exchangers. Particularly, the existence of an energy sink results in cooler solid particles as compared to the flowing fluid.

Heat recovery from granular flow in moving bed heat exchangers has wide industrial applications. However, more knowledge is still necessary for the heat transfer enhancement. For the slow descending of random particles, the flow structure has crucial roles on the heat transfer by conduction and radiation. In this paper, the effect of tube inclination was studied by discrete element method. Influences of particle update, contact and radial migration were carefully discussed. Moreover, heat resistance analysis was conducted to explore the clear law. It was found that, the heat is obviously improved by tube inclination due to the increasing area, but there are uncertainties for the local heat transfer coefficients. At the tube bottom, particles become denser with tube inclination, which is beneficial to increase the heat transfer coefficient. But for the top or middle area, there are two opposite effects. Tube inclination enhances radial migration around tube wall, while simultaneously weakens local particle update. Finally, contact resistance firstly increases and then decreases with inclination angle, but there is a reversal tendency for the sensitivity of penetration resistance to the flow rate. In actual applications, penetration resistance is the major resistance, and the inclination angle is therefore suggested between 15° and 37.5°.