Optimization Of Heat Exchanger Research Articles

Experimental optimization of the performance of a plate heat exchanger with Graphene oxide/water and Al₂O₃/water nanofluids

The heating and cooling process is a major industrial challenge. The efforts to improve the design of heat transfer improvement mainly center around expanding the heat transfer area (through the geometry of the heat exchanger) and inducing turbulence to eliminate the boundary layer. A solution to increase the thermal efficiency of the heat exchanger and reduce costs is the use of materials such as nanofluids with ideal thermal and thermophysical properties. Here, to enhance the effectiveness of nanofluids and prevent sedimentation, atomic stabilization was the main focus by combining surfactants with nanofluids at specific weight concentrations and applying ultrasonic vibrations to increase stability. In this paper, the influence of using Graphene oxide (GO)/water and AL2O3/waternanofluids and the GO–AL2O3 /water hybrid nanofluid was investigated at 0.01 %, 0.02 %, 0.03 % wt concentrations. The effect on heat transfer and thermal efficiency of a plate heat exchanger relative to the base fluid (water) was examined. The nanofluids were stabilized in several stages to optimize the thermodynamic properties of the base fluid. The thermal efficiency of the nanofluids (η) reaches to its maximum at the highest weight concentration (0.03 %) with GO nanoparticles at 37 %, AL2O3 at 21 %, and the GO–AL2O3 hybrid at 26 %. GO nanoparticles had the most significant impact on the heat exchanger performance, with an optimized heat exchanger performance of 15.94 %, followed by the hybrid at 11.86 %, and AL2O3 at 7.4 %.

Economically optimized heat exchanger design: a synergistic approach using differential evolution and equilibrium optimizer within an evolutionary algorithm framework

Economically optimized heat exchanger design: a synergistic approach using differential evolution and equilibrium optimizer within an evolutionary algorithm framework

A Formulated Method for Streams Splitting in Heat Exchanger Network Design Using Pinch Analysis

Abstract Thermal processes constitute a significant portion of energy consumption in the industrial sector. In this context, pinch analysis has emerged as a powerful method for achieving substantial energy savings. By systematically analyzing process streams and their heat transfer characteristics, pinch analysis enables the identification of heat recovery opportunities, leading to the design of an optimized heat exchanger network that minimizes energy requirements. In this study, a formulated stream splitting method is proposed to design a feasible minimum energy requirement heat exchanger network. This method aims to achieve two main goals. First, it gives a practical formulated method to help the designer when splitting streams and focuses on splitting the streams in such a way that creates sub-streams with the exact enthalpy required to satisfy heat exchanges with a specific number of streams, in order to minimize the need for process-utility heat exchangers whenever possible. Subsequently, the method aims to eliminate exergy destruction caused by temperature differences in the mixer used to recombine the split streams, by ensuring an isothermal mixture of streams, preventing unnecessary energy losses. The design of the heat exchanger network is conducted using the hint software, allowing for a comprehensive and detailed analysis of each step. The results obtained show that the heat exchanger network attained not only achieves the minimum energy consumption but also mitigates exergy destruction and avoids unnecessary process-utility heat exchangers, resulting in enhanced overall system performance.

Local entropy generation optimization and thermodynamic irreversibility analysis of oval-shaped coaxial ground heat exchangers: A detailed numerical investigation

Optimizing the heat transfer and thermodynamic efficiency of Ground Heat Exchangers (GHE) is crucial for maximizing the energy efficiency of Ground-coupled Heat Pump (GCHP) systems utilized in building heating and cooling applications. This study pioneers an effective approach of both the first and second laws of thermodynamics of the newly oval-shaped coaxial GHEs (oval-CGHEs), assessing heat transfer, thermohydraulic performance, and local entropy generation rate to explore the optimum design and operational conditions for heat exchange maximization and entropy generation minimization. Utilizing a three-dimensional numerical model validated by experimental results, this study examines the trade-offs between heat transfer improvements and entropy generation rate intensification of the oval-CGHEs in comparison to the typical circular-shaped CGHE (circle-CGHE) further than exploring the effect of key operational and design parameters and performing sensitivity analysis. The results reveal that oval-CGHEs exhibit higher irreversibility as a penalty for their superior heat transfer capabilities compared to traditional circular-shaped CGHEs (circle-CGHE), which can be mitigated by optimizing the position of the inner tube. Moreover, the study underscores the criticality of maintaining a balance between enhanced heat transfer and the associated rise in irreversibility, particularly concerning the factors of mass flow rates and installation depths.

Performance evaluation and multi-objective optimization of a hybrid earth-air heat exchanger and building-integrated photovoltaic/thermal system with phase change material and exhaust air heat recovery

The current study explores the feasibility of employing an integrated system comprising an earth-air heat exchanger (EAHE) unit and a photovoltaic/thermal (HPT) system equipped with a phase change material (PCM) to fulfill the heating, cooling, and electrical loads of a building. In this arrangement, ambient air is heated during cold months by passing it through the EAHE and PCM-based HPT systems, and during hot months, it is cooled by passing through the EAHE unit. Additionally, in warm months, the air exiting the building is utilized to lower the temperature of the PV panels. The electricity generated by the PV panels is harnessed to meet a portion or the entirety of the building's electrical demand. Following the identification of factors influencing the system performance, the multi-objectives genetic algorithm (MOGA) approach is employed to ascertain the optimal values of these parameters, aiming to concurrently maximize both the thermal and electrical output of the HPT-EAHE system. The findings indicated that the optimal HPT-EAHE system can fulfill 132693.3 kWh of heating demand for the building during cold months, address 26536.1 kWh of cooling needs during hot months, and generate 9242.2 kWh electrical power throughout the entire year.

Enhancing heat transfer efficiency in corrugated tube heat exchangers: A comprehensive approach through structural optimization and field synergy analysis

In this paper, a precise and efficient method to optimize corrugated tube heat exchangers is proposed by combining computational fluid dynamics simulation with optimization. The optimization of tubular heat exchangers involves contradictory Colburn coefficient j, and the friction coefficient f, so it is a multi-objective optimization problem. The approximate model is obtained by an extreme learning machine, and the structure parameter of the heat exchanger is optimized by the nondominated sorting genetic algorithm-Ⅱ. Compared to the results between the original and optimized tube, the optimized structure Colburn coefficient increased by 5.1 % and the friction coefficient decreased by 9.3 %. Finally, the internal flow field is compared qualitatively from temperature, pressure, and velocity. The optimization effect is further emphasized by using the field synergy theory.

Allocation optimization of two-stage compression-absorption heat exchanger

Space heating demand of buildings is a significant component of global energy consumption. Lowering the operating temperatures can increase the overall energetic and exergetic efficiencies. To obtain a lower return water temperature, researchers have proposed a variety of approaches. Absorption heat exchanger is an effective way to reduce return water temperature. However, in two-stage absorption heat exchanger and compression-absorption heat exchanger, extra temperature difference exists in evaporator of absorption heat pump. To eliminate the extra temperature difference, optimized compression-absorption heat exchanger is put forward in the article. Based on the typical case, the energy saving rate of optimized compression-absorption heat exchanger can reach 17.9 %, and the principle of energy saving is analyzed in the article, the key point is the extra temperature difference and the cooling capacity of evaporator of absorption heat pump. Further, the energy savings of the optimized heat changer in different supply and return temperature of primary and secondary network is analyzed. Main factors affecting the energy saving rate are primary network supply temperature and secondary network supply-return temperature difference. As the result, when primary network supply temperature is 130 °C and secondary network supply and return temperature is 50 °C and 40 °C, energy saving rate can reach 28.4 %.

Optimization of Elliptical U-tube Heat Exchanger (EUTHE) for Spray Cooling Based on the Taguchi and CFD Method

The elliptical U-tube heat exchanger (EUTHE) is widely used in various cooling systems of nuclear engineering for its simple geometrical structure and small space cost. In this paper, a two-phase flow field model of an EUTHE is constructed to analyze the flow characteristics in the elbow zone under different structures with the influence mechanism of droplet motion and liquid film distribution. The Taguchi method is used to investigate the influence of heat transfer performance by structural parameters, and the fitted model is analyzed by regression analysis as well as ANOVA to ensure the accuracy of the prediction results. The results show that thick tubes have a wider liquid film distribution because they are more difficult to trap droplets, achieving high heat transfer capacity while reducing separation efficiency and pressure drop. In addition, the heat transfer capacity and the pressure drop are mostly improved by the increase of the U-tube cross-section long axis length (L2) at the expense of reduced separation efficiency. The optimal cases for each target were obtained by analyzing the influence mechanism of each structural factor, for example, the largest heating tube section (L1) and the U-tube cross-section long axis length (L2), to determine which will lead to the highest heat transfer capacity, which mainly is due to the fact that an increase in these factors leads to the increment of contact area between the fluid and the wall. This work provides a guideline for the design of EUTHE and brings greater benefits to the development of nuclear engineering.

Parametric analysis and multi-objective optimization of heat exchangers in CGS stations: replacement with water bath heaters

Parametric analysis and multi-objective optimization of heat exchangers in CGS stations: replacement with water bath heaters

Reduced order model for flow distribution in tapered headers of U-type heat exchangers

Flow maldistribution in the channels of plate heat exchangers (PHEs) results in uneven temperature distribution leading to thermal distortion of the plates, increased pressure drop, and reduced thermal efficiency. Ensuring a uniform flow distribution is paramount for the efficiency and reliability of these systems. Using a modified header shape has the potential to improve flow conditions. To date, there is no mathematical model to predict flow distribution for tapered headers in PHEs. In this context, a reduced-order model has been developed to rapidly assess the potential impact of tapered headers on flow distribution. This model marks a pioneering effort in developing a comprehensive model for estimating flow distribution and pressure drop applicable to both uniform and tapered headers of U-type PHEs, providing valuable insights without necessitating significant computational resources. Key structural parameters, such as header diameter, number of channels, channel area, and taper ratio, that influence flow distribution have been identified by solving the differential equations numerically. For tapered headers, a more uniform flow distribution occurs with fewer plates for the same flow resistance, i.e., the average total head loss coefficient (ζ). Beyond a critical header diameter, the flow remains nearly uniform, regardless of the ζ value. For higher ζ values, there is a channel area range where flow uniformity either increases or remains nearly uniform. One of the most significant findings is the identification of the conditions where tapered headers provide more flow uniformity compared to straight headers. Validated by existing literature, this model shows promising practical applications in the rapid design and optimization of plate heat exchangers.

Parametric design optimization and thermodynamic analysis of plate fin heat exchanger for helium liquefaction system

The plate-fin heat exchanger is one of the most important components of helium liquefaction system as it recovers cold energy from helium gas in the cold box. Because of larger heat transfer surface area and compact geometrical configuration, plate-fin heat exchangers are widely used. The design of heat exchanger using helium as a cryogenic fluid needs high thermodynamic performance with minimum pressure drop which particularly requires the optimization of dimensional array and its geometrical configurations. In this regard, a parametric investigation was performed to compute the effective geometrical parameters and its effect on thermodynamic (effectiveness and log-mean temperature difference) performance has been discussed in detail. The present study aims to design optimization and thermodynamic performance evaluation of plate-fin type heat exchangers used in helium liquefaction systems. The developed helium liquefaction model has been simulated for the most critical liquefier with and without liquid nitrogen precooling, mixed mode, and refrigeration mode. Each component of the liquefaction model has been technically and thermodynamically analyzed and, in particular, four plate-fin heat exchangers have been considered and designed accurately using Aspen EDR®. Initially, the sensitivity analysis was carried out to characterize the most significant geometrical parameters (fin thickness, height, number and arrangement of layers, frequency, and fin type) and their effect on thermodynamic performance and pressure drop. After that, the artificial intelligence model was used to determine the optimal range of such geometrical variables in which the heat exchanger has maximum effectiveness and log mean temperature difference. Finally, the operating conditions obtained from cycle modeling and optimized geometrical datasets have been applied in commercial simulation software Aspen EDR® for plate-fin heat exchangers design. Finally, a comparative thermodynamic analysis has been carried out to determine the performance of all the designed heat exchangers operating at four different modes (boundary conditions).

Innovative design for thermoelectric power generation: Two-stage thermoelectric generator with variable twist ratio twisted tapes optimizing maximum output

In recent years, considerable effort has been dedicated to the development of highly efficient thermoelectric generators for waste heat recovery and thermoelectric power generation. In this study, we present employing twisted tapes with variable twist ratio to enhance thermal energy extraction efficiency, coupled with two-stage thermoelectric modules for heat-to-electricity conversion, resulting in a substantial increase in the power output of the thermoelectric generator. We established an experimental system that validated the superior power generation and heat recovery characteristics of the two-stage thermoelectric generator. Building upon these findings, we propose further optimizing the variable twist ratio twisted tapes to enhance the power output. We investigated the impact of tape pitch ratio, twist ratio, and twist ratio variation range on thermoelectric performance. Experimental results indicate that the influence of flow instability is more pronounced than that of swirl intensity, and twist tapes with the maximum twist ratio variation rate yield the highest net output power. Compared to an unmodified thermoelectric generator, the two-stage thermoelectric generator employing twist tapes with a twist ratio increase from π to 3π achieves a maximum net output power gain of up to 100%. These findings provide a practical framework for integrating innovative power generation modules and optimized heat exchanger designs into the application of waste heat recovery thermoelectric generators, marking a significant advancement in the field of thermoelectric generators.

Numerical investigations and design optimization of cryogenic plate-fin heat exchanger in Electric Arc Furnace using radiative heat transfer model

The most crucial element affecting cryogenic systems’ energy efficiency is heat exchangers. In this article, a model for cryogenic plate-fin heat exchanger (PFHE) under thermal-hydraulic performance with various blends is proposed. To reduce five objective functions total heat transfer rate, total weight, total mass flow rate, number of entropy generating units, and whole annual cost the study carried out the PFHE’s optimal design. This study innovatively focuses on optimizing PFHE design for cryogenic conditions using Opposition Learning with the Beetle Swarm algorithm. The proposed geometry addresses non-uniform temperature distribution, emphasizing thermal-hydraulic properties in various blends. Additionally, a second-order semi-discretization radiative heat transfer approach enhances boiler simulation accuracy. A multi-objective optimization of Opposition Learning with Beetle Swarm (MO-OBBS) optimization approach was suggested in the article for the design of PFHE. Despite the significant potential for renewable energy the low-temperature waste heat treatment process is rarely examined from a sustainability perspective. Consequently, the study proposed a second-order semi-discretization radiative heat transfer method to simulate a furnace using a water heat recovery process. The cooling panel’s numerical analysis was conducted using computed temperature fields. The performance of the various algorithms is compared using the Freidman rank-sum test to determine the statistical significance of the findings obtained. In logarithmic coordinates, the proposed method’s faster convergence is compared to GQB-PSO, SLTLBO, Jaya, CKKO, and OLE-SCA algorithms. The proposed method exhibits a maximum average increase of 115.39% for PFHE design. When the numerical simulation results are compared to measurements of output water temperature, the accuracy is highly improved.

Study on Heat Transfer Synergy and Optimization of Capsule-Type Plate Heat Exchangers

An efficient and accurate method for optimizing capsule-type plate heat exchangers is proposed in this paper. This method combines computational fluid dynamics simulation, a backpropagation algorithm and multi-objective optimization to obtain better heat transfer performance of heat exchanger structures. For plate heat exchangers, the heat transfer coefficient j and friction coefficient f are a pair of contradictory objectives. The optimization of capsule-type plate heat exchangers is a multi-objective optimization problem. In this paper, a backpropagation neural network was used to construct an approximate model. The plate shape was optimized by a multi-objective genetic algorithm. The optimized capsule-type plate heat exchanger has lower flow resistance and higher heat exchange efficiency. After optimization, the heat transfer coefficient is increased by 8.3% and the friction coefficient is decreased by 14.3%, and the heat transfer effect is obviously improved. Further, analysis of flow field characteristics through field co-ordination theory provides guidance for the further optimization of plates.

Numerical Study of the Thermo-Hydro-Mechanical Coupling Impacts of Shallow Geothermal Borehole Groups in Fractured Rock Mass on Geological Environment

Fractured rock mass is extensively distributed in Karst topography regions, and its geological environment is different from that of the quaternary strata. In this study, the influences on geological environment induced by the construction and operation of a large-scale borehole group of ground source heat pumps are analyzed by a thermo-hydro-mechanical (THM) coupling numerical model. It was found that groundwater is redirected as the boreholes can function as channels to the surface, and the flow velocity in the upstream of borehole group is higher than those downstream. This change in groundwater flow enhances heat transfer in the upstream boreholes but may disturb the original groundwater system and impact the local geological environment. Heat accumulation is more likely to occur downstream. The geo-stress concentration appears in the borehole area, mainly due to exaction and increasing with the depth. On the fracture plane, tensile stress and maximum shear stress simultaneously occur on the upstream of boreholes, inducing the possibility of fracturing or the expansion of existing fractures. There is a slight uplift displacement on the surface after the construction of boreholes. The correlations of the above THM phenomena are discussed and analyzed. From the modeling results, it is suggested that the consolidation of backfills can minimize the environmental disturbances in terms of groundwater redirection, thermal accumulation, occurrence of tensile stress, and possible fracturing. This study provides support for the assessment of impacts on geological environments resulting from shallow geothermal development and layout optimization of ground heat exchangers in engineering practices.

A new CO2 refrigeration system with two-phase ejector and parallel compression for supermarkets

This study explores the integration of parallel compression and a two-phase ejector in transcritical CO2 refrigeration systems, aiming to improve efficiency and performance. This innovative approach bridges the gap between conventional approaches and explores new energy-saving potential. The study uses thermodynamic modeling, mathematical simulation, and in-depth analysis to look at energy and exergy performance in a new configuration for applications in the retail sector at medium evaporation temperatures. The work investigates thermodynamic phenomena in a novel cycle with steady-state conditions, low pressure differentials, and adiabatic efficiency. The model is validated against experimental and theoretical published data, revealing component-specific exergy destruction and key parameters. The novel cycle efficiently extracts heat at higher temperatures, outperforming conventional and parallel cycles. Exergetic efficiency surpasses the standard cycle, with gas cooler pressure and temperature dependence enhancing efficiency by 40%–45%. The distribution of exergy destruction percentages reveals efficiency determinants, emphasizing heat exchange optimization and ejector responsiveness in energy dissipation dynamics. The study investigates the coefficient of performance (COP) dependence on gas cooler pressure and temperature, revealing superior performance compared to conventional cycles. COP increases by 50% at 80 bars, indicating enhanced efficiency. The new cycle offers exceptional efficiency gains, with a COP enhancement of over 75% for evaporator temperature transitions. Comparative analysis shows a COP superiority of up to 53% for lower evaporator temperatures and 20% for higher evaporator temperatures, demonstrating substantial energy savings and improved performance across various operating conditions.

DEVELOPMENT OF RECOMMENDATIONS FOR OPTIMIZATION OF TECHNOLOGICAL PROCESSES OF PROCESSING AND USE OF HEAT AND MASS EXCHANGE EQUIPMENT FOR DRYING LEGUMES

The article is devoted to the development of recommendations for the optimization of technological processes of processing and the use of heat and mass exchange equipment for drying legumes. Legumes are an important source of protein and other nutrients in the food and feed industry, and their drying plays a key role in preserving and increasing shelf life. The article includes analysis of technological processes, selection of optimal heat and mass exchange equipment, control of temperature and humidity, reduction of losses of useful substances and implementation of a quality monitoring and control system. Optimizing these processes will help increase production efficiency and improve the quality of dried leguminous herbs, contributing to the development of the industry and meeting the demand for valuable products. In this context, our article is devoted to the development of recommendations for the optimization of technological processes of processing and the use of heat and mass exchange equipment for drying legumes. By combining scientific analysis, practical experience and innovative approaches, we set ourselves the task of developing integrated recommendations that will contribute to increasing the efficiency of the drying process, reducing the loss of useful substances and improving the quality of dried legumes. An important aspect of our article is not only the theoretical base and scientific research, but also a practical approach to solving this problem. We hope that the developed recommendations will find practical application in the agro-industrial sector, contributing to the conservation of resources, increasing the quality and competitiveness of products and contributing to the sustainable development of this important industry.

Unsteady MHD Nanofluid Flow Through a Divergent Conduit with Chemical Reaction and Radiation

Inefficient heat transfer rates have resulted in high energy consumption costs in heat exchanger systems. In this study, unsteady MHD(Magneto-hydrodynamics) Nanofluid flow (Silver-water) through a divergent conduit with chemical reaction and radiation is investigated. The chemical reactions taking place within the Nanofluid are considered to be of first order with the radiation effects being in a steady state. The governing partial differential equations have been transformed into ordinary differential equations using similarity transformations. The resulting system of non-linear ordinary differential equations is then solved using the spectral collocation method and implemented in MATLAB software. The results for velocity, temperature, and concentration profiles are presented graphically and discussed. It was observed that increasing the Reynolds number and Hartmann number led to an increase in the velocity profile. Increasing the Eckert number and Joule heating parameter increased the temperature profile while increasing the radiation parameter led to a decrease in the temperature of the Nanofluid. The concentration of the Nanofluid increased with an increase in the Soret number and Chemical reaction parameter while the concentration decreased with an increase in the Schmidt number. The findings have practical applications in designing and optimizing heat exchangers by maximizing heat transfer thus contributing to the sustainability of geothermal power generation in the energy industry.

Engine oil blended Casson hybrid nanofluid flow along a uniformly heated curved surface with Arrhenius activation energy and suction: A computational study

The research studies the numerical analysis of an incompressible Casson hybrid nanofluid, composed of Fe3O4–Cu nanoparticles blended with engine oil, flowing over an exponentially stretched curved surface. It explores the effects of an aligned magnetic field, a uniform heat source, activation energy, and suction while maintaining a low Prandtl number. By employing appropriate similarity transformations, the original partial differential equations are converted into ordinary ones and solved using bvp4c in MATLAB. Graphs and tables depict the influence of dimensionless factors on skin friction coefficient, velocity, thermal, and concentration profiles, as well as Nusselt and Sherwood numbers. The computational findings reveal that magnetic field alignment significantly modifies velocity, decreasing it while uniformly enhancing temperature and concentration profiles. Casson fluid behavior in engine oil amplifies temperature and concentration profiles, thereby enhancing heat and mass transfer rates. Moreover, an increased heat source elevates temperature but reduces overall heat transfer. The chemical reaction parameter diminishes concentration, whereas activation energy enhances it, albeit impacting the mass transfer rate conversely. Additionally, suction increases flow resistance, while the stretching parameter exhibits an inverse effect, both positively influencing heat and mass transfer rates at higher values. Practically, these findings offer insights crucial for optimizing heat exchangers, biomedical devices, and cooling systems, enhancing their efficiency and performance. Additionally, they inform the design of industrial processes involving fluid flow, aiding in the development of more effective and sustainable solutions.

Exploring novel heat transfer correlations: Machine learning insights for molten salt heat exchangers

The utilization of molten salts in heat transfer applications, specifically within shell-and-tube heat exchangers, has garnered significant attention for its potential in sustainable energy solutions. this study employs advanced machine learning algorithms, including decision tree regressor, support vector regressor, extreme gradient boosting, and random forest, to not only predict the heat transfer behavior of molten salts but also unravel the complex mechanisms underlying this process. Achieving a remarkable accuracy score of 0.985, the Support Vector Regressor leads the predictive models, closely followed by random forest (0.982), Decision Tree Regressor (0.974), and Extreme Gradient Boosting (0.965). The incorporation of Shapley Additive exPlanations values accentuates the Reynolds number’s pivotal role, elucidating a robust correlation with the Nusselt value. These insights transcend mere prediction, offering a profound understanding that can significantly impact the design and optimization of molten salt heat exchangers. The applications of molten salts extend across various sectors, including concentrated solar energy and thermal storage, solidifying their position as a versatile and effective solution in the pursuit of sustainable and efficient energy systems.