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The miniaturization of electronic devices without compromising their heat dissipation capacities is the main concern due to the rapid evolution in power industries and engineering fields. The conventional methods of cooling or heating the devices are changed and old tactics of using conventional fluids for heat dissipation are replaced with nanofluids of strong thermal efficiency. In the present context, the experimental as well as theoretical studies of nanofluids (Cu–H2O/Al2O3–H2O) flow inside the wavy and microchannels are elucidated and discussed for different physical conditions. It is found that the use of Cu–H2O/Al2O3–H2O nanofluid improves the thermal efficiency of heat exchangers. The complex shapes and sizes of heat exchangers such as multilayer heat exchangers, heat exchangers with twisted and square shapes and multijet heat exchangers are considered effective coolants as compared with straight microchannel heat exchangers. The use of Cu–H2O/Al2O3–H2O nanofluids improves the overall heat transfer efficacy of electronic devices, and it is considered a promising coolant for various applications including aerospace (spacecraft and satellites), automobile (cooling the engines and power management in electric vehicles), renewable energy (solar plants), microelectronic devices (heat dissipation through the microprocessor and cooling the other components of devices) and modern heat exchangers of engineering domains. [ABSTRACT FROM AUTHOR]

In order to have a heat transfer per volume, heat exchangers have to have high overall heat coefficient. The effects of a transverse wedge on the heat transfer, the pressure drop, and the thermal efficiency factor (TEF) of air flow through a tube bundle heat exchanger was investigated. TEF increases continuously with the wedge aspect ratio (α). Form α = 0.275, 0.550, 0.758 to 1, TEF increases continuously from 1.157 to 1.84, 1.11 to 1.72, 1.05 to 1.42, and 1.02 to 1.39 for x/L = 1/3, 2/3, 1, and 0, respectively. [ABSTRACT FROM AUTHOR]

Turbulators are used in heat exchangers to increase the contact surfaces of fluids and enhance heat transfer rates by promoting turbulence flow. This is particularly important in applications that require high productivity and capabilities. The use of turbulators can lead to maximum energy efficiency, resulting in high efficiency and lower costs. This investigation presents a comprehensive experimental and computational fluid dynamics (CFD) approach into the influence of turbulator-induced disturbances on heat transfer characteristics in a double pipe heat exchanger. In this study, two innovative turbulators (named TY and TZ) were designed to enhance the performance of heat exchangers. The turbulators are inserted into the inner pipe of the double pipe heat exchanger. According to the experimental and numerical results, compared to the plain pipe condition (without turbulator), it was observed that maximum temperature differences were reached with a 28% increase at velocity of 2.5 m/s with TY and 118% increase at velocity of 3 m/s with TZ. Nusselt numbers increased by 32% with TY and by 157.9% with TZ compared to the plain pipe condition. Therefore, TZ turbulator with a simple structure can significantly enhance the heat transfer performance of double-pipe heat exchangers, making it an ideal option for use in these exchangers. [ABSTRACT FROM AUTHOR]

Heat exchangers are widely used in petrochemical and other industries. Improving the efficiency of heat exchangers to increase energy utilization is crucial. Passive enhanced heat transfer technology is widely studied in heat exchanger research due to its low energy consumption and simple operation. Helical baffle–corrugated tube heat exchangers have not been extensively studied as a promising new class of these devices. This paper investigates the key structural parameters of a helical baffle-corrugated heat exchanger through numerical simulation. This study focuses on the factors affecting heat transfer and flow resistance performance. The results show that reducing the helical angle from 28.42° to 10.81° increases the total heat transfer coefficient by approximately 20%. The overall performance of the heat exchanger is evaluated using the efficiency evaluation coefficient (EEC). Optimal levels of each structural factor are determined for different working conditions based on this evaluation. [ABSTRACT FROM AUTHOR]

The potential of hybrid nanofluids to boost thermal efficiency of heat exchanger systems is the focus of this review study. The primary focus is on addressing the associated issues of nanoparticle clumping, system obstruction, and reduced efficacy of heat exchanger due to increased fluid thickness. Accordingly, this review intends to demonstrate the innovative practices (experimentally and theoretically) that helps improving the heat transfer and thermal performance of heat exchangers. In this regard, a critical analysis is conducted to appraise the experimental and numerical simulations, which introduce the impact of different nanoparticle concentrations and compositions on heat exchanger thermal performance. The findings of this review has shown that the hybrid nanofluid of CuO–Cu/water has the greatest thermal performance factor (1.065), following Al2O3–Cu/water (1.055), and Cu–TiO2/water (1.039). Also, the utilization of turbulator heat exchangers has enabled improving the thermal performance by 126 % with a 6 % rise in volume fraction at the maximum Reynolds number. This study underlines the need for further research into novel nanomaterial combinations, fine-tuning of fluid characteristic, and comprehensive stability assessments to enhance the utilization of hybrid nanofluids in heat exchanger systems. Finally, discussions of limitations associated with such systems and proposed potential solutions will lead to a valuable contribution in the possible future development of cost-effective heat exchanger systems. [ABSTRACT FROM AUTHOR]

This paper presents a comparative analysis of a finned heat exchanger fed with synthetic refrigerant R410a and environmentally friendly refrigerant R290. Analyses of the performance of the heat exchanger operating as an evaporator in a refrigeration system were carried out. Simulation studies were performed using SOLIDWORKS software with the Flow Simulation library. The analysis was conducted for various design parameters of the device. The performance of the exchanger was examined for different fin materials (aluminium alloys: alloy 1060, 1060-H12, alloy 2014, alloy 2024), number of fins (78 and 39), and fin spacings (2.5 mm and 5 mm). The studies were conducted under various operational parameters of the exchanger (varying volume flow of air and refrigerant mass flow). Based on the results obtained, it was found that the material of the exchanger does not significantly affect its performance. The next conclusion is that when the heat exchanger is fed with an environmentally friendly refrigerant, the heat transfer surface area can be reduced by 50%. As a result, the reduction in heat transfer surface area can be achieved by increasing the fin spacing, which will reduce the electricity consumed in the defrost process under operating conditions, or by reducing the size of the exchanger, which will positively translate into a reduction in the weight of the refrigerant in the system. The possibility of reducing the dimensions of the heat exchanger by up to 50% indicates that replacing R410a refrigerant with environmentally friendly R290 is a promising direction for development. It advocates for ongoing investigations to refine these systems and maximize the operational advantages presented by natural refrigerants. [ABSTRACT FROM AUTHOR]

The study is focused on the use of nanofluids in a micro-open tall cavity, which is a type of micro heat exchanger (MHE). The cavity is heated from the bottom sidewall in a sinusoidal pattern, and the effects of four input parameters (Ra, Ha, Kn, and Vf) on heat transfer and irreversibility are investigated using numerical simulations based on Lattice Boltzmann Method (LBM). The findings of the study suggest that the local heat transfer on the bottom sidewall is strongly influenced by Ra and Ha, while the surface distribution of entropy generation is mainly dependent on Kn. The study also shows that the optimization of the magnitude and wavelength of the sinusoidal temperature can improve both local heat transfer and surface distribution of entropy generation. The results of the study provide valuable insights into the design of micro heat exchangers and suggest that the optimization of micro-porous geometries using DOE could lead to increased energy efficiency. The study contributes to our understanding of the complex interactions between input parameters in micro heat exchangers and highlights the importance of considering multiple parameters in the design process. [ABSTRACT FROM AUTHOR]

Thermal storage technology has received increasing attention under the policy of encouraging the development of renewable energy and new clean energy. Optimizing the heat exchange system of phase change thermal storage heat exchangers to obtain better performance has become increasingly urgent. This study comprehensively investigated the actual process of heat transfer and assessed the heat transfer correlation laws between the heat transfer fluids, heat exchange tubes, fins, and phase change materials. Taking the heat exchange efficiency of the heat exchanger as a guide, a simulation was conducted on the effect of the presence and quantity of fins as well as the flow rate of the cooling liquid on the heat exchange efficiency of the heat exchanger. The simulation results showed that too many or too few fins were not conducive to improving heat transfer efficiency. In addition, no positive correlation was observed between the flow rate of the cooling liquid in the heat exchanger and the heat transfer efficiency of the heat exchanger. Specifically, models with slightly slower cooling liquid flow rates had a higher heat transfer efficiency. After a sensitivity analysis, it was found that the number of fins had a more significant effect on the heat transfer efficiency of the heat exchanger than the flow rate of the cooling liquid. The heat exchanger with five fins and a cooling liquid flow rate of 0.1 m/s demonstrated the best heat transfer effect, achieving a temperature drop of 14.76% within 5 min. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to conduct a practical investigation of heat transfer (HT) and friction factor (f) characteristics within a double pipe heat exchanger (DPHE) configured in a counter-flow arrangement. To achieve this, a novel approach involving twisted tape (TT) with dimple inserts accompanied by adjacent holes working fluid is water implemented. This dimples, characterized by their concave geometry, are strategically employed to augment the heat exchange process while concurrently mitigating any adverse impact on fluid pressure. A pivotal facet of this study centered on examining the influence of dimple diameter, as well as a consistent dimple-to-depth ratio (D/H), on both heat transfer efficiency and friction factor. The performance of TT inserts featuring diverse diameter (D) = 2, 4 and 6 mm is meticulously scrutinized in terms of their impact on heat transfer and friction factor characteristics. The outcomes of the study furnished intriguing insights. It is observed that the diameter of the dimples wielded a discernible encouragement on friction factor, revealing a direct correlation. The maximum rate of friction factor is recorded at a 2 mm dimple diameter configuration. When evaluating Nusselt number (Nu) and performance evaluation criteria (PEC), it is revealed that the most favorable results is achieved with the 4 mm dimple diameter configuration. Drawing upon these empirical findings, a significant conclusion can be drawn. Utilization of twisted tape inserts adorned at dimples is a practical, efficient and economically viable approach to heighten HT efficiency within heat exchangers. By optimizing dimple diameter and adhering to a consistent diameter-to-depth ratio, substantial improvements in HT capabilities can be harnessed without disproportionately compromising fluid pressure. This innovative methodology holds the potential to revolutionize heat exchanger design, offering an avenue to enhance HT efficiency with practical and cost-effective solutions. [ABSTRACT FROM AUTHOR]

A novel BHEs is proposed that can overcome the problems associated with the low heat-transfer efficiency of borehole heat exchangers (BHEs) that are connected in series (BHEs-S) and the low heat-transfer temperature differences of BHEs that are connected in parallel (BHEs-P). The new BHE uses a combined series and parallel connection (BHEs-CSP), which can further be classified into individual in-series and in-parallel zones. A numerical model of the new BHEs-CSP is then developed to optimize the key design parameters such as borehole spacing, number of series stages, and heat-extraction methods. The results show that, with the optimal configuration, the average soil temperature with a BHEs-CSP is 6.70°C higher than for a BHE that is connected in parallel. Furthermore, the heat-transfer efficiency can be improved by 4.1% compared to BHEs that are connected in series. It is recommended that the distance between buried pipes in the series area and parallel area should be 5.25 m, and the series number of buried pipe groups should be 4. To study the overall performance of the solar-assisted ground-source heat-pump with a BHEs-CSP (SAGSHP-CSP), a TRNSYS model is developed. The results show that the optimal area- and heat-storage-ratios (for in-series zone to inparallel zone), using SAGSHP-CSP, are 1:4 and 3:2, respectively. Under these conditions, the system coefficient of performance (SCOP) is over 5.2 and the COP and SCOP is improved by 9.8% and 13.0% compared to GSHP systems with BHEs-P. Furthermore, an improvement by 18.4% and 18.2%, compared to the GSHP system with BHEs-S, is reported. [ABSTRACT FROM AUTHOR]

Heat exchangers make it possible to utilize energy efficiently, reducing the cost of energy production or consumption. For example, they can be used to improve the efficiency of gas turbines. Improving the efficiency of a heat exchanger directly affects the efficiency of the device for which it is used. One of the most effective ways to intensify heat exchange in a heat exchanger without a significant increase in mass-dimensional characteristics and changes in the input parameters of the flows is the introduction of turbulators into the heat exchangers. This article investigates the increase in efficiency of heat exchanger apparatuses by introducing turbulent lattice structures manufactured with the use of additive technologies into their design. The study is carried out by numerical modeling of the heat transfer process for two sections of the heat exchanger: with and without the lattice structure inside. It was found that lattice structures intensify the heat exchange by creating vortex flow structures, as well as by increasing the heat exchange area. Thus, the ratio of convection in thermal conductivity increases to 3.03 times. Also in the article, a comparative analysis of the results obtained with the results of heat transfer intensification using classical flow turbulators is carried out. According to the results of the analysis, it was determined that the investigated turbulators are more effective than classical ones, however, the pressure losses in the investigated turbulators are much higher. [ABSTRACT FROM AUTHOR]

This paper studies the optimization design of capillary heat exchangers and their innovative engineering applications in buildings. The purpose of this study is to use a capillary heat exchanger as the front-end device of the heat pump in coastal areas to extract energy to facilitate the application of renewable energy in buildings. Firstly, in this paper, the main factors of capillary heat transfer efficiency were explored in areas near the coast. Secondly, for the sake of improve the heat transfer efficiency of the capillary heat exchanger, numerical calculations were carried out on the heat transfer of the capillary in the case of inconsistent operating patterns in the summer and winter months, respectively. The results showed that when the daily working time of the capillary heat exchanger was 8 hours, the temperature difference of the capillary inlet and outlet was 2.1 ℃. And the heat transfer rate was 87.1 W/m² . In summer, the temperature difference of the capillary inlet and outlet was 2.6 ℃. And the heat transfer rate was 107.8 W/m² . This article helps to promote innovative and sustainable technologies in coastland development, such as capillary heat exchangers and heat pumps, which could used in renewable energy extraction and building utilization in near coastal areas. [ABSTRACT FROM AUTHOR]

The heat transfer improvement and the increase of heat exchangers’ efficiency represent a very important issue in the energy field. Many research projects have focused on the use of fluids with high thermal conductivity such as nanofluids. In this case, hybrid nanofluids, are a new class of nanofluids with good heat transfer characteristics. The present work falls within this framework and involves a numerical study to examine the influence of two oil-based hybrid nanofluids, Al2O3-MWCNT and MgOMWCNT, with different volume concentrations and inlet flow rates. More to the point, the impact of different nanoparticle ratio and the location of hybrid nanofluid in a laminar flow of two-pipe counter-current heat exchanger have been investigated. In virtue of which, the results illustrate that increasing the volume concentration of nanoparticles and the flow rate of the hybrid nanofluid has a positive impact on improving the heat transfer rate. Therefore, the improvement in heat transfer rate reached 77.8% for Al2O3-MWCNT/oil hybrid nanofluid and 59.5% for MgO-MWCNT/oil hybrid nanofluid. Similarly, the study has also revealed that the preferred nanoparticles ratio for Al2O3-MWCNT/oil hybrid nanofluid is in the order of (25:75) and its circulation in the inner tube as a hot fluid makes it possible to improve the thermal performance of the considered two-tube heat exchanger to a greater advantage. [ABSTRACT FROM AUTHOR]

The heat exchanger is a core component of all thermal systems. Thus, high-efficiency heat exchangers that can save energy and material are required. Heat transfer improvement in heat exchangers by applying the newly designed fin configuration increases the heat exchanger efficiency. Moreover, the newly designed finned heat exchanger improved heat transfer, resulting in a significant reduction in the heat exchanger size. A compact countercurrent water–water heat exchanger with a high rate of heat transfer while using the least amount of space was achieved. The newly designed finned tube on the outer surface of the inner tube in this study increased the heat transfer characteristics of the double-pipe heat exchanger. An insulated Perspex shell with an inner diameter of 54 mm, 2000 mm in length, and 3 mm thick. Copper tubes with and without rectangular copper fins are studied and compared. The smooth copper tube was 2250 mm in length with 20 mm and 22 mm inner and outer diameters, respectively. The experimental results showed that the Nusselt number and effectiveness of the newly proposed finned tube increased by 95% and 127%, respectively, compared to those of the smooth tube at the same Reynolds number, while the heat transfer coefficient increased by 53% over a smooth tube. [ABSTRACT FROM AUTHOR]

This article addresses the design of a compact heat exchanger for the cooling of electronic systems. The Quality Function Deployment (QFD) method is used to identify crucial product features to improve device performance and key customer requirements. The QFD simplifies management processes, allowing modifications to device components, such as design parameters (dimensions and materials) and operating conditions (flow type and preferred temperature range). The study was applied to analyse the fundamental features of a compact heat exchanger, assessing their impact on enhancing heat transfer intensity during fluid flow through mini-channels. The thermal efficiency of the compact heat exchanger was tested experimentally. The results allow to verify the results obtained from the numerical simulations due to Simcenter STAR-CCM+. Consequently, the experimental part was reduced in favour of numerical simulations conducted using this commercial CFD software version 2020.2.1 Build 15.04.01. The numerical simulations performed with the aid of CFD showed increases in the heat transfer coefficient of up to 180% compared to the case treated as a reference. The application of the QFD matrix significantly reduces the time required to develop suitable design and material solutions and determine the operating parameters for the cooling of miniature electronic devices. [ABSTRACT FROM AUTHOR]

To demonstrate the rationalization of multi-longitudinal swirls in heat exchanger tubes, this paper investigates the thermohydraulic performance of heat exchanger tube with rectangular vortex generator using numerical simulation. Comparative analyses of rectangular vortex generators and their different slotted structures are conducted, along with the investigation of the effect of the longitudinal pitch (P = 0.1 m, 0.2 m and 0.3 m) of the rectangular vortex generators on the thermohydraulic performance. The research reveals that the multi-longitudinal swirls induced by the vortex generator inside the tube accelerate the exchange of cold and hot fluids, improve the field synergies of velocity vectors and temperature gradients, and enhance the heat transfer efficiency of the heat exchanger tube. The slotted structure reduces the flow resistance and lowers the degree of disturbance to the fluid, which reduces the strength of the multi-longitudinal swirls, thus weakening the overall performance of the heat exchanger. The strength of the multi-longitudinal swirls has a direct influence on the overall performance of the heat exchanger tube. With the increase of P, the performance evaluation criteria (PEC) of the heat exchanger tubes decreases, and the maximum PEC = 1.44 is obtained for P = 100 mm at the studied Reynolds number range. [ABSTRACT FROM AUTHOR]

To improve the efficiency of the heat exchanger tube, one smooth tube and four doubly enhanced tubes (EX1, EX2, EX3 and EX4) have been investigated for the pool boiling heat transfer experiments in this paper. The indicate that the pool boiling heat transfer coefficient of the doubly enhanced tubes increased visibly with the augmentation of heat flux through the bubble behavior. Heat transfer reinforcement effect of the doubly enhanced tubes are significantly better than that of the smooth tube. Additionally, pool boiling heat transfer coefficient can be further enhanced by raising the saturate temperature. Entropy generation minimization analysis demonstrates that the heat transfer characteristics of like T-shaped tubes (EX1 and EX2) are superior to that of low fin tubes (EX3 and EX4). Particularly, tube EX1 exhibits higher pool boiling heat transfer efficiency. It is observed that a reasonable fin pitch is more advantageous for improving heat transfer characteristics. The utilization of entropy generation minimization analysis provides theoretical support for the design and optimization of doubly enhanced tubes. [ABSTRACT FROM AUTHOR]

Absorption cooling technology is an environmentally friendly method to generate continuous chilled water making use of multiple thermal sources, such as waste heat and renewable thermal energy. In this study, two absorption chillers (nominal capacity of 400 kW) with series and parallel connections are evaluated. To research the ideal configuration of chillers after thermodynamic analysis, the structures of the chillers are optimized using the particle swarm optimization algorithm by considering the heat transfer area (HTA), exergy efficiency and total annual cost as single-objective functions. The impact of temperature differences between external and internal flows, heat exchanger efficiencies and the solution allocation ratio is estimated. The optimized HTA, coefficient of performance, exergy efficiency and total annual cost are 149.0 m2, 1.56, 29.44% and $229 119 for the series-connected chiller, and 146.7 m2, 1.59, 31.45% and $234 562 for the parallel-connected type, respectively. Under the lowest HTA condition, compared with the reference simulation results, the energy and exergy performances are improved, while the annual total cost is higher. The annual total cost is highest when maximizing the exergy efficiency, which is attributed to the increase in the HTA. The operating cost accounts for 27.42% (series type) and 26.54% (parallel type) when the annual cost is the lowest. [ABSTRACT FROM AUTHOR]

In this study, we aim to investigate the heat transfer and flow characteristics of diverse hybrid nanofluids (CuO-ZnO-Water, EG-Water, CuO-EG-Water, SiO2-EG-Water, and Al2O3-EG-Water) as coolants across eight discrete inlet velocities in a shell and tube heat exchanger. Various materials (copper, stainless steel, titanium, and carbon steel) have been employed for the tubing to optimize system performance. The impact of Reynolds number concerning hybrid nanofluids on Nusselt number and friction factor was assessed in this research. The results of the numerical simulations are found to agree well with experimental results within an average deviation of 1.8%. The results indicated the superior heat transfer capabilities of the hybrid nanofluid compared to the base fluid across all conditions. The outcomes revealed the superior heat transfer capabilities of the CuO-ZnO-Water hybrid nanofluid under all tested conditions. When employing CuO-ZnO-Water as a coolant, a substantial increase of over 9% in temperature reduction was observed, as opposed to the approximately 6% attained by other hybrid nanofluids at a lower velocity of 0.5 m/s. Notably, higher Reynolds numbers corresponded to increased Nusselt numbers and decreased friction factors. The decline percentage of the friction factor was 43% at Reynolds number ranging between 10,000 to 40,000. We emphasize the imperative need to optimize nanoparticle types for crafting hybrid nanofluids to enhance the performance of industrial heat exchangers and their coolant efficiency. Ultimately, the utilization of hybrid nanofluids in conjunction with shell and tube heat exchanger systems has yielded a notable enhancement in the overall thermal efficiency of these systems. [ABSTRACT FROM AUTHOR]

Heat exchangers enable processing plants to maintain maximum performance over time when handling variable process conditions. The most frequent heat exchanger issues, however, can occasionally be far more challenging to fix, resulting in high capital expenses and rising running costs. Consequently, there is a crucial need to redesign the current heat exchanger for improved performance. In this work, a shell and tube-type heat exchanger is designed with the help of CREO 8.0 parametric software. Transient thermal analysis is done to the designed model using ANSYS 2022 R2 software to investigate different shell and tube heat exchanger materials and assess the heat exchanger for its efficiency and temperature gradient. These results can be used to design appropriate heat exchangers in stationary energy systems, including power plants and fuel cell systems. [ABSTRACT FROM AUTHOR]

Spiral heat exchangers are designed to meet the most difficult heat transfer challenges. Whether it's frequent dirt removal or limitations related to pressure drop and installation space, they are the ideal solution to problems for liquid-liquid and two-phase loads. Robust, efficient and compact models keep installation and maintenance costs extremely low. Compared to other heat exchangers commonly used in similar applications, spiral designs offer a compact footprint and increased thermal efficiency. Built with unique features that prevent fouling, they can handle the toughest heat transfer challenges while ensuring the most reliable performance. They work consistently, with extremely low installation and maintenance costs. [ABSTRACT FROM AUTHOR]

Improvements in heat exchanger thermal efficiency are crucial for achieving energy use and cost reductions. The use of nanofluids and the rotation of the exchanger inner tube may enhance heat transfer and exchanger efficiency. In this work, after having performed experiments on such a heat exchanger, a three dimensional numerical model was developed to simulate the transitional forced convection flow of a horizontal double-tube heat exchanger, with the aim of obtaining insight into the effects of the inner tube rotation, fluid flow rate and type of nanofluid employed. It was found that an increase in the nanoparticle concentration up to 3% increased the exchanger efficiency. Al2O3, Al2O3-Cu and Cu-water nanofluids were studied, with the Cu-water being the fluid with the best performance (19.33% improvement). Heat transfer was enhanced with inner tube rotation up to 500 rpm (41.2%). Nevertheless, pressure drop and friction values were increased due to both phenomena, leading to higher pumping power values for the operation of the heat exchanger. Hence, a balance between the performance and pumping power increase must be considered when modifications are made on a heat exchanger. The development of the numerical model might help in further optimizing, redesigning and scaling up heat exchangers. [ABSTRACT FROM AUTHOR]

One of the main priorities in the modern thermal power engineering development is the problem of energy saving due to the economical use of fuel and energy reserves. Increasing energy consumption with a simultaneous increase in energy prices and widespread environmental degradation necessitates the development and implementation of energy efficient technologies to save fuel, materials and labour costs. The object of study is tubular heat exchangers of variable cross section, which are widely used in steam generators of nuclear power plants, gas turbines and transport plants. Scale deposit properties and the composition of the heat coolant were studied, and their influence on the energy efficiency of heat exchangers was analysed. To study the scale deposits and coolant influence on the energy efficiency of heat exchangers, their properties were examined using an atomic emission analysis with the help of a TESCAN electron microscope. The principles of implementing technologies aimed at intensifying heat transfer, reducing hydraulic and heat losses in heat exchangers were formulated. [ABSTRACT FROM AUTHOR]

The present study investigates the effects of using a magnetic field on the flow field and heat transfer of ferromagnetic Fe3O4/H2O nanofluid considering two-phase model for nanofluid in heat exchanger equipped with helical ribs. Three methods are employed to enhance the thermal efficiency of heat exchanger, as employing of corrugations, utilizing nanofluid as heat transfer fluid, and employing the magnetic field. The performance evaluation criteria index (PEC) is employed to analyze the thermal-hydraulic characteristics of the heat exchanger. The main aim is to achieve an optimum model with the highest performance evaluation criteria value. Usaging of corrugated heat exchanger or nanofluid can increase the average Nusselt number and friction factor in the tube sharply. Also, it is understood that the presence of a magnetic field has a significant effect on the heat transfer enhancement inside the heat exchanger. The model with magnetic field of 600 G has the highest Nusselt number ratio among all studied models, which is followed with 400 G, 200 G, and 0 magnetic fields, respectively. Furthermore the effects of different corrugation heights, widths, and pitches have been studied. Finally, usage of the novel corrugated heat exchanger with 14 mm corrugation heights, 9 mm rib width, and 12.5 mm blade pitches filled with nanofluid, and under a magnetic field of 600 G it suggested as the most efficient configuration. Also, at the Reynolds number of 4,000, the highest performance evaluation criteria values are achieved. [ABSTRACT FROM AUTHOR]

Heat exchangers have a very wide range of applications in many industrial fields, so the rational design and the performance are to improve the heat exchanger energy efficiency and reduce the production cost of an important means. In this paper, the heat transfer mechanism of pulsation is revealed by simulating and analyzing the effects of three pulsation parameters: volumetric flow rate, pulsation frequency, and pulsation amplitude on the flow and heat transfer of a wavy-walled tube heat exchanger, with the study focusing on the instability behavior that affects the heat transfer mechanism. The results reveal that the combined heat transfer performance of the wavy-walled tube heat exchanger is about 8.2% higher than that of the straight-walled tube heat exchanger. The flow field of the heat exchanger is more fully developed under the pulsating flow field, and its performance evaluation coefficients (PECs) are all greater than 1. It is also found that with the increase in the volume flow rate Qv, the heat transfer enhancement coefficient and PEC first increase and then decrease, and reach the maximum value near Qv = 2.0 m3/h; with the increase in the amplitude A, the vortex and heat transfer enhancement coefficient inside the heat exchanger increase, but the integrated heat transfer performance of the heat exchanger is gradually weakened; with the increase in the frequency fT, the heat transfer enhancement coefficient and PEC first increase gradually, but the increase gradually decreases and levels off in the later stages, reaching a maximum value near fT = 0.5 Hz. Meanwhile, the field coefficients of the wavy-walled tube heat exchanger were analyzed and found to be much smaller than 1, with an order of magnitude of 10−4, and the results also showed that the field coefficients were inversely proportional to the volume flow rate and directly proportional to the amplitude of pulsation and that the field coefficients showed a tendency of increasing and then decreasing with the change of pulsation frequency and reached a maximum value near fT = 0.5 Hz. This work provides an important reference for current manufacturing industries to optimize heat exchanger sizing and develop efficient thermal management systems. [ABSTRACT FROM AUTHOR]

At the city gate gas pressure reduction stations (CGSs), to prevent natural gas from forming a hydrate in the throttle valve, the natural gas is heated by the heater before reaching the pressure relief valve. Heat exchangers are an essential component of industrial processes that contribute significantly to total system energy. Since the element impacting heat exchanger performance is the fouling process, all fouling processes and models were dynamically simulated in this study. Through coding in the C++ language and simultaneous use of fluent functions, or, in other words, user‐defined function (UDF), fouling‐related models were defined for this software. The dynamic simulation was performed, and parameters such as fouling strength and layer thickness were calculated. The effects of changing operating conditions, such as gas inlet velocity, surface temperature, and fouling species concentration on fouling growth, were also evaluated. As the concentration of fouling species increased, the fouling rate also increased. The amount of supersaturation and fouling rate increased as the surface temperature increased. Due to the operational limitations of the system, to reduce the fouling rate, the gas inlet velocity should be as high as possible, and the fluid inlet temperature, surface temperature, and concentration of fouling species should be as low as possible. In this study, the required time to reach the efficiency of 70% of the heat exchanger was calculated using the modelling of this chamber, which was equivalent to 190 days. Additionally, the critical thickness of the fouling layer at this time was 3.5 cm. [ABSTRACT FROM AUTHOR]

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Optimizing the efficiency of conventional heat exchangers is critical for improving the performance of various processes. This study proposed increasing the heat dissipation buffer space of heat exchangers by filling the gap between the heat exchanger and the shell with phase‐change materials for optimizing phase‐change heat exchangers. Comparative simulation analyses were performed by investigating the difference between the internal and external diameters of the inner ring ribs of the heat exchanger, the flow rate of the cooling liquid, the spacing distance, and the number of the inner ring ribs as independent variables. The results revealed that the heat transfer efficiency of heat exchangers can be improved by adding the inner ring rib structure to the heat exchange copper tube. The difference between the inner and outer diameters of the inner ring rib considerably influences heat dissipation. Furthermore, a sensitivity coefficient of 0.2457 can be obtained. The distance and number of inner ring ribs and the flow rate of cooling liquid exhibit certain effects on the heat transfer efficiency of the heat exchanger. The sensitivity coefficients were 0.1477 and 0.0935. The heat dissipation efficiency of the coil heat exchanger was improved by 3.8% by adding inner ring ribs in the coil heat exchanger channel. [ABSTRACT FROM AUTHOR]

The thermal efficiency of heat exchangers, heat sinks, solar heaters, etc., could be optimized by improving the heat transfer in the system without increasing the exergy destruction. It is important to consider pressure loss as well as heat transfer enhancement to increase overall energy efficiency. One of the most effective methods to increase heat transmission with minimal pressure drop penalty is by deploying vortex generators. In this paper, a detailed review of the synergy angle, angle of attack, friction factor, Nusselt number, flow configuration, Reynolds number, and the impact of geometry of the vortex generators on the enhancement of heat transfer and exergy is presented. The principles of field synergy and exergy are utilized to predict the thermo-hydraulic performance of the vortex generators. Different geometries of vortex generators such as rectangular, delta, trapezoidal winglets, and other novel geometries of vortex generators are installed in varied flow configurations and analyzed based on field synergy and exergy principles which were not the matter of interest in review papers in the past. [ABSTRACT FROM AUTHOR]

In this research, using Harris Hawks optimization method, the gasket-plate heat exchangers is studied with an exergy-economic approach. Six parameters of hot fluid inlet temperature, cold fluid inlet temperature, hot fluid mass flow rate, cold fluid mass flow rate, port diameter and the number of plates were selected as design variables. The ratio of hot fluid mass flow rate to cold fluid mass flow rate, λ, is introduced to the analysis of exergy loss. The results showed that using Harris Hawks optimization method, exergy loss and total cost can be reduced by 70% and 81%, respectively. The optimization results showed that minimizing the exergy loss, the efficiency of the gasket-plate heat exchanger increases by 30%. It is also found that for λ>1, with the increase of cold fluid mass flow rate, the exergy loss number decreases and for λ<1, with the increase of cold fluid mass flow rate, the exergy loss number increases. [ABSTRACT FROM AUTHOR]

The high demand for compact heat exchangers has led researchers to develop high-quality and energy-efficient heat exchangers at a lower cost than conventional ones. To address this requirement, the present study focuses on improvements to the tube/shell heat exchanger to maximize the efficiency either by altering the tube's geometrical shape and/or by adding nanoparticles in its heat transfer fluid. Water-based Al2O3-MWCNT hybrid nanofluid is utilized here as a heat transfer fluid. The fluid flows at a high temperature and constant velocity, and the tubes are maintained at a low temperature with various shapes of the tube. The involved transport equations are solved numerically by the finite-element-based computing tool. The results are presented using the streamlines, isotherms, entropy generation contours, and Nusselt number profiles for various nanoparticles volume fraction 0.01 ≤ φ ≤ 0.04 and Reynolds numbers 2400 ≤ Re ≤ 2700 for the different shaped tubes of the heat exchanger. The results indicate that the heat exchange rate is a growing function of the increasing nanoparticle concentration and velocity of the heat transfer fluid. The diamond-shaped tubes show a better geometric shape for obtaining the superior heat transfer of the heat exchanger. Heat transfer is further enhanced by using the hybrid nanofluid, and the enhancement goes up to 103.07% with a particle concentration of 2%. The corresponding entropy generation is also minimal with the diamond-shaped tubes. The outcome of the study is very significant in the industrial field and can solve many heat transfer problems. [ABSTRACT FROM AUTHOR]

A study of heat recovery in a façade ventilation unit was carried out under laboratory conditions using a climate chamber that allowed stable outdoor and indoor conditions to be simulated. The unit, equipped with a reversible fan and a chamber for the heat exchanger, controlled by an automation control system, was designed to exchange air in the room by alternating supply and exhaust cycles of specific durations. Three types of heat exchangers were tested, which were filled with different phase change materials, in order to estimate the efficiency of the façade ventilation unit in terms of its heat recovery capability. The efficiency of the unit was determined based on the temperature efficiency of heat recovery for 144 setting combinations. The best efficiency results between 73.56% and 76.29% were obtained with a solution using a heat exchanger consisting of cylinders with an external diameter of 10 mm and a wall thickness of 1 mm filled with jojoba oil in a one minute cycle. The tests confirmed that the heat exchangers, which are part of the façade ventilation unit, fulfil their function and allow heat recovery from the exhaust air to pre-heat the supplied air. The study complements the existing scientific knowledge on the efficiency of heat exchangers filled with phase change material, operating in winter conditions with work cycles up to 5 min. [ABSTRACT FROM AUTHOR]

In this study, the fullerenes have been inserted into water base-fluid to investigate the atomic and thermal behavior of nanofluid and hybridnanofluid as heat transfer fluid. This choice derives from low cast and high thermal stability of this nanostructure. Our computational results from Molecular Dynamics (MD) simulations indicate that the addition of nanoparticles with 4% atomic ratio produced an appreciable effect on the nanofluid. The maximum value of density, velocity, and temperature profile have reached to 0.029 atom/(cubic°A), 0.005 °A/ps, and 321 oC. Its thermal conductivity would increase to 0.82 W/mK Heat flux reached to 2019 kW/m2 after t= 10 ns. Also, the aggregation phenomenon detected after t= 5.84 ns. This hybridnanofluid has been used to enhance the energy efficiency of the heat exchangers at high temperature for the nuclear industry applications for the first time. Numerically, by the temperature increase of nanofluid structure to 625.15 K, thermal power of nanofluid reached to 3881 MW. The thermal performance of hybridnanofluid can be improved by more than 30% by adding concentration of fullerene and doped fullerene at 4 vol%. [ABSTRACT FROM AUTHOR]

The most common type of heat exchanger used in a variety of industrial applications is the shell-and-tube heat exchanger (STHE). In this work, the impact of graphene nanoplate (GNP)/water nanofluids at 0.01 wt.%, 0.03 wt.%, and 0.06 wt.% on the thermal efficiency, thermal performance factor, pressure drop, overall heat transfer, convective heat transfer coefficient (CVHTC), and heat transfer characteristics of a shell-and-tube heat exchanger was examined. For these experiments, a new STHE was designed and built. The novelty of this study is the use of GNPs/water nanofluids in this new STHE for the first time and the fully experimental investigation of the attributes of nanofluids. GNP properties were analysed and confirmed using analyses including XRD and TEM. Zeta potential, DLS, and camera images were used to examine the stability of nanofluids at various periods. The zeta potential of the nanofluids was lower than -27.8 mV, confirming the good stability of GNP/water nanofluids. The results illustrated that the experimental data for distilled water had a reasonably good agreement with Sieder-Tate correlation. The maximum enhancement in the CVHTC of nanofluid with 0.06 wt.% of GNP, was equal to 910 (W/m2K), an increase of 22.47%. Also, the efficiency of the heat exchanger for nanofluid at 0.06 wt.% improved by 8.88% compared with that of the base fluid. The heat transfer rate of the nanofluid at maximum concentration and volume flow rate was 3915 (J/kg.K), an improvement of 15.65% over the base fluid. The pressure drops increased as the flow rate and concentration of the nanofluid increased. Although increasing the pressure drop in tubes would increase the CVHTC, it would also increase the power consumption of the pump. In conclusion, nanofluid at 0.06 wt.% had good performance. [ABSTRACT FROM AUTHOR]

The rising use of fossil fuels has had major environmental impacts, including global warming, pollution, and higher heating system costs. This emphasizes the need of increasing the efficiency of equipments such as heat exchangers used in heating and air conditioning systems. In the present study, heat transfer augmentation in a double pipe heat exchanger is numerically studied by the use of truncated conical turbulators. Truncated conical structures with a base diameter of 12 mm height, 7 mm, and pitch values ranging from 25 mm to 100 mm with an increment of 25 mm, have been considered in the study. The air flow rate varied from a Reynolds number of 3000 to 15,000 in increments of 3000. Results have been compared with the bare pipe without any turbulators. The heat exchanger with the turbulator showed better performance than the bare heat exchanger in terms of higher Nu, but at the cost of higher pressure drop. Increased Nu was observed up to pitch 50 mm and reduced afterward. Results indicated a highest Nu of 77.7 for Pitch 50 mm at Re 15,000. Maximum Thermohydraulic efficiency of 1.13 was observed for pitch 50 mm at a Re of 11,000. Hence, it is concluded that truncated conical structures can be used as a heat augmentation device in a double pipe heat exchanger to increase the heat transfer rate and thermohydraulic efficiency. [ABSTRACT FROM AUTHOR]

With the application of microdevices in the building engineering, aerospace industry, electronic devices, nuclear energy, and so on, the dissipation of high heat flux has become an urgent problem to be solved. Microchannel heat sinks have become an effective means of thermal management for microdevices and enhancements for equipment due to their higher heat transfer and small scale. However, because of the increasing requirements of microdevices for thermal load and temperature control and energy savings, high efficiency heat exchangers, especially microchannels are receiving more and more attention. To further improve the performance of microchannels, optimizing the channel geometry has become a very important passive technology to effectively enhance the heat transfer of the microchannel heat sink. Therefore, in this paper, the microchannel geometry characteristics of previous studies are reviewed, classified and summarized. The review is mainly focused on microchannel geometry features and structural design to strengthen the effect of heat transfer and pressure drop. In addition, the correlation between boiling heat transfer and geometric characteristics of microchannel flow is also presented, and the future research direction of microchannel geometry design is discussed. [ABSTRACT FROM AUTHOR]

The fouling factor is a complex non-linear function of several feature variables. Accurate estimation of this measurable factor is applicable for controlling the heat transfer efficiency of heat exchangers. Artificial neural network (ANN) and adaptive neural-based fuzzy inference system (ANFIS) techniques are accurate approaches for the understanding treatment of the most complicated systems. The cascade-feedforward (CFF), multi-layer perceptron (MLP), radial basis function (RBF), and generalized regression (GR) neural networks and ANFIS were applied for predicting the fouling factor of the hot wire probe from some measured variables using a huge databank, including 1870 empirical dataset. Pearson's and Spearman's techniques confirmed the highest relation between considered features and the first order of fouling factor. The results demonstrate that the cascade feed-forward neural network containing eight hidden neurons was the best artificial intelligence (AI) model with excellent overall AARE = 3.44 %, MSD = 0.0000315, RMSD = 0.0056, and R2 = 0.9982. This work's significance lies in presenting an applicable and accurate tool for estimating fouling factors on hot wire probes to the research community and industry. This model can be considered a reliable replacement for empirical analyses that are often expensive and time-consuming. [Display omitted] • Hot wire probe has used in academic studies of fouling in heat transfer surfaces. • Five powerful artificial intelligence models are used for fouling factor estimation. • The Levenberg-Marquardt is found as the best training algorithm. • An accurate CFF neural network with eight neurons in one hidden layer developed. • Effects of less studied and various independent variables on fouling is simulated. [ABSTRACT FROM AUTHOR]

The improvement of the efficiency of heat exchangers has always been one of the most critical concerns of industry. Pulsating heat pipes are a new and high-efficiency technology in the field of heat transfer. Pulsating heat pipes are widely used in solar water heaters, solar water desalination systems, etc. In this study, the effect of different nanofluids on the performance of heat pipes was investigated. ZrO2/SiO2 nanocomposites were tested under functionalized and non-functionalized states in a pulsating heat pipe. For this purpose, the heat pipe was charged with each nanofluid at concentrations of 0.25, 0.5, and 1 g L−1, and the thermal resistance of the pipe was compared as an output parameter. The thermal resistance for different nanofluids was defined and compared at different input powers of the evaporator and a constant filling ratio of 50%. The obtained results showed that nanofluids as a working fluid could improve the heat transfer of pulsating heat pipe compared to the working fluid of water and reduce the thermal resistance. The nanofluid with a concentration of 0.25 g L−1 exhibited the best performance. In this case, the resistance of pulsating heat pipe at some fluxes was decreased up to 48%. [ABSTRACT FROM AUTHOR]

• Introduces ultra-compact TPMS heat exchangers with record efficiency up to 16.5 W/(cm³·K). • Successfully 3D prints complex TPMS structures, enabling new design possibilities. • Develops experimental correlations in heat transfer and pressure drop. • Achieves up to 200 % improvement in PEC over traditional heat exchangers. With the rapid growth in energy efficiency demands, compact heat exchangers are gaining increasing attention. This study proposes a novel heat exchanger design based on Triply Periodic Minimal Surface (TPMS) structures, leveraging their unique three-dimensional porous structure to enhance heat transfer efficiency and compactness. This study employs computational fluid dynamics (CFD) simulations to analyze the thermal performance of three TPMS structures (Gyroid, Diamond, and Fischer-Koch S) heat exchangers. Two optimized structures are selected for additive manufacturing based on the simulation results. The manufactured heat exchangers are inspected using CT scans, and a dual-fluid experimental performance testing system is constructed to assess the potential application of the two heat exchangers in thermal management systems. Using the least squares method, correlations for heat transfer and pressure drop are separately fitted for the two TPMS heat exchangers. Dimensionless Performance Evaluation Coefficient (PEC) values are utilized to analyze the comprehensive performance of the two TPMS heat exchangers. The heat transfer rate per unit volume has increased by approximately 50 times compared to traditional heat exchangers reported in the literature, which reaches an impressive 717.7 W/cm3 and 16.5 W/(cm³·K). This study will provide design guidance for enhancing the compactness and efficiency of TPMS heat exchangers. [ABSTRACT FROM AUTHOR]

• The mechanism of heat conduction of printed circuit heat exchanger with anisotropic thermal conductivity was numerically investigated. • The synergistic effect of thermal resistance in three directions of the solid region on the performance of the heat exchanger was revealed. • A solid region thermal resistance ratio optimization method was proposed. • The efficiency of the heat exchanger is improved by approximately 23% through solid region thermal resistance ratio manipulation. Printed Circuit Heat Exchangers are compact and efficient heat exchangers, widely used in nuclear engineering, very high-temperature reactors, and aerospace systems. This study investigates the heat transfer performance of a heat exchanger with anisotropic thermal conductivity, such as fiber reinforced composites. Numerical simulations were conducted to examine the synergistic effect of three-dimensional thermal resistance on heat exchanger performance. The most significant impact on performance is the z-direction thermal resistance, followed by the y-direction, while the x-direction has the least impact. Contrary to traditional design thinking, increasing the overall heat exchanger thermal resistance under the same thermal resistance ratio improves heat transfer efficiency at the studied conditions. The results suggest that it is necessary to design the lowest thermal conductivity direction as the z-direction and increase the y-direction thermal conductivity to enhance heat exchanger performance. In the numerical investigation presented in this study, the efficiency of the heat exchanger was improved by approximately 23 % under specific operating conditions by adjusting the thermal conductivity of anisotropic materials to control the thermal resistance in the x, y and z directions. It is evident that the manipulation of anisotropic material properties has a substantial influence on the performance of heat exchangers. [ABSTRACT FROM AUTHOR]

Airfoil-finned printed circuit heat exchanger (PCHE) is a new type of microchannel heat exchanger with high efficiency and stable compact features for high temperature and high pressure supercritical carbon dioxide Brayton cycle system. Usually, only one kind of fin structure is used in the microchannel heat exchangers, and little research has been done on flow heat transfer of hybrid fins structure. In this work, a new model of heat exchanger with hybrid fins structure is developed with supercritical carbon dioxide (S–CO 2) as the flow medium. Specifically, three-dimensional numerical simulations of PCHE are performed to study the flow heat transfer characteristics of hybrid fins. Besides, the effect of the different spacing of the airfoils on the flow heat transfer performance is studied. The results show that when the left and right adjacent spacing of the fins L b increases, the heat transfer performance of the heat exchanger improves while the pressure drop decreases. With the same pressure drop, the heat transfer of microchannel heat exchanger increases with the increase of the upper and lower adjacent spacing of the fins L c. Besides, the heat transfer performance of the new hybrid microchannel heat exchanger is much better than that of the conventional zigzag microchannel heat exchanger. The new hybrid fin microchannel heat exchanger shows better heat transfer performance at high Reynolds number, compared with that of the swordfish fin, airfoil fin and rhombic fin microchannel heat exchangers. [ABSTRACT FROM AUTHOR]

Here, to resolve the open problem of the second-law efficiency evaluation for heat exchangers, an efficiency-effectiveness method is developed from pure convection theory, where the entropy transfer efficiency defined as the outlet temperature ratio of cold and hot fluids exchanging entropy and local entropy generation number can measure the global and local irreversibilities of heat transfer. The efficiency and effectiveness are related by the inlet temperature ratio τ and capacity rate ratio φ , and their maxima subject to the local entropy generation number are determined for different flow arrangements. When τ = φ 2, the effectiveness maxima are 0.5/(1 + φ) and 1/(1 + φ) while the highest efficiencies are φ and unity for parallelflow and counterflow arrangements, respectively. The optimum operating points of counterflow exchangers, at which the equal outlet temperature τ T 1 ∞ (T 1∞ represents the hot inlet temperature) of two fluids with a critical capacity rate ratio τ induces uniform irreversibility, the effectiveness limit of 1 / (1 + τ) , and the efficiency limit of unity, are obtained. A linear temperature difference method is also developed based on the redefined convective and overall heat transfer coefficients, invariably yielding an effectiveness equal to the number of heat transfer units. This method has potentials to be extended to wet heat exchangers with phase-change flows. • The open question of second-law efficiency evaluation of a heat exchanger is resolved. • The heat transfer effectiveness and entropy transfer efficiency limits are presented. • The global and local irreversibilities of exchangers are measured by N S and N S,l. • Two optimum design criteria of exchangers are obtained subject to N S,l. [ABSTRACT FROM AUTHOR]

To address the issue of low efficiency in cooling heat exchangers at the deeper ends of mine fans, we propose a micro-unit approach for arranging the cooling water flow path within the heat exchanger. This method involves subdividing the heat exchanger into micro heat transfer units and determining the heat transfer characteristics of each individual unit through theoretical calculations and software simulations. Utilizing a computer program, these micro units are systematically arranged and combined to exhaust all possible cooling water flow paths. The ultimate objective is to derive the optimal structural arrangement of the cooling water flow path within the heat exchanger, with the goal of achieving the most efficient heat transfer effect. The findings reveal that the optimized structure, obtained through the micro-unit optimization method, achieves an average air outlet temperature of 311.65 K. This temperature is lower than that of the typical current-flow structure (311.88 K) and the typical counter-flow structure (311.68 K), indicating a superior heat transfer effect. Further examination demonstrates that the average air outlet temperature across all counter-flow structures is 311.68 K, which is notably lower than the average air outlet temperature of 311.90 K observed in the current-flow structure. This highlights the enhanced heat transfer effectiveness of the counter-flow structure. This novel method for optimizing the heat exchanger flow path applies the concept of finite element analysis to the optimization process, reducing computational and experimental costs. This approach is significant for improving the efficiency of heat exchangers. [ABSTRACT FROM AUTHOR]

It has been reported that about 50% of the total amount of fuel in an oil refinery plant is consumed in crude oil and vacuum distillations. Thus, the heat exchanger networks of crude oil distillation units significantly affect the overall energy efficiency and CO2 emissions of refinery plants. Crude oil fouling in heat exchanger networks is one of the most troublesome problems in crude oil refineries. It reduces heat transfer amount or blocks the flows in tubes, leading to requiring additional fuel for the furnace following heat exchanger networks. Therefore, many cleaning methods have been developed. Mechanical cleaning of heat exchangers is the most effective method to mitigate the fouling in heat exchangers. However, it is necessary to open heat exchangers for cleaning. So, the timing of mechanical cleaning is limited because the normal refinery operation must be stopped. Therefore, to keep the good energy and economic performance of the refinery, it is necessary to predict the appropriate maintenance timing and to conduct a suitable cleaning. To find a suitable cleaning schedule or timing, the authors proposed a method for predicting fouling resistance in near future for crude oil fouling from actual online plant data in this research. The prediction results are in good agreement with the measured results, which demonstrate that the proposed method is effective for predicting the cleaning timing for the industry in the future. [ABSTRACT FROM AUTHOR]