Three-fluid Heat Exchanger Research Articles

Model development and validation of a vapor-compression system integrating water-based thermal energy storage using a three-fluid heat exchanger (TriCoil™)

This paper presents a comprehensive simulation suite for a residential heating and cooling system that combines a vapor-compression system (VCS) with a water-based thermal energy storage (TES) using a three-fluid heat exchanger (TriCoil™). The VCS configuration includes the TriCoil™ as the indoor coil, a fin-and-tube heat exchanger as the outdoor coil, a variable-speed compressor, and an isenthalpic expansion device. To minimize computational cost for annual simulations, an artificial neural network (ANN) was employed to develop a data-driven model for the TriCoil™. The suite integrates models of the VCS, TES, and control systems, factoring in utility rates, building load profiles, and weather data. Validation against experimental data demonstrated accurate predictions, with TES temperature profiles having a root mean square error of 0.3 K and VCS heating capacity predictions showing mean absolute errors of 4.3% for the R410A side, 5.0% for the water side, 4.9% for the air side, and 4.3% for the air-sensible side.Simulations for a cooling season in Stillwater, OK, demonstrated significant electricity cost reductions by shifting cooling loads from peak to off-peak hours. The proposed system minimizes expenses using time-of-use rates and optimized load scheduling, showcasing substantial benefits even with a small TES unit.

Thermo-hydraulic performance of metal oxide nanofluid flow through the helical coil tube of a three-fluid heat exchanger: an experimental and optimization study

ABSTRACT The thermo-hydraulic performance of a three-fluid heat exchanger (TFHE) to concurrently transfer heat from a heated nanofluid to ordinary water and air is the subject of investigation in this paper. The fluid flow and heat transfer abilities of the TFHE concerning changes in nanofluid (Al2O3-water, CuO-water, Fe2O3-water) are used to quantify effectiveness and pressure drop. Parametric studies having nanofluid volume fraction (1%, 5%, and 10%), flow rate (100LPH, 150LPH, and 200LPH), and inlet temperature (80°C, 120°C, and 160°C) respectively are considered in the present experimentation. The results of the experiment demonstrate that the use of CuO-water nanofluid at an intake temperature of 160°C and 5% volume percentage led to a considerable improvement in heat transfer effectiveness, with a maximum value of 0.884. At a flow rate of 100 LPH, a volume percentage of 1%, and an inlet temperature of 160°C, the Al2O3-water nanofluid exhibits the least amount of pressure loss. Nine test runs with four control factors are conducted using Taguchi’s experiment design. From Taguchi analysis, it is observed that the nanofluid volume flow rate and nanofluid inlet temperature have the largest and lowest contributions of 68.83%, 3.76%, and 72.05%, 2.03% respectively on heat transfer effectiveness and pressure drop of the TFHE. A multi-response optimization is carried out using the Taguchi-Gray Analysis to determine the least pressure drop and the highest possible heat transfer effectiveness. At 1% volume fraction, 100 LPH volume flow rate, and 160°C intake temperature, Al2O3-water nanofluids show an increase in the total performance of the TFHE of 10.39%.

Experimental investigation of three fluid heat exchangers using roughness on the outer surface of a helical coil

AbstractThe aim of this study is to utilize waste thermal energy from industries into useful heat for water and air heating. In this paper, the thermal modeling and performance of three fluid heat exchangers (TFHE) have been experimentally investigated. The TFHE considered here is an enhanced version of the double‐pipe heat exchanger. A novel TFHE having fin (1 mm thin copper wire of 10 mm pitch) acts as a roughness element, which is wrapped on the helical coil's outer surface for increasing heat transfer (HT) rate and the turbulence effect for normal water, and this outer surface finned helical coil is inserted between two concentric straight tubes. The innermost tube carries atmospheric air, the finned helical coil tube carries waste hot fluid while normal water flows in the inner annulus of the outermost tube. The coiled‐side Reynolds number is varied in the range of 7000–30,000, while the curvature ratio of 0.1315, pitch‐to‐inside diameter ratio of 2.88 and wire‐to‐tube diameter of the helical tube is kept constant. A counterflow arrangement has been made for experimentation. Nusselt number is calculated using the traditional Wilson plot method that is compared and validated with results available in the literature. The overall HT coefficient is found to increase by increasing the volume flow rate of fluids, while effectiveness decreases or increases depending on residence time and capacity ratio. The percentage increment in the Nusselt number, maximum friction factor, overall HT coefficient between waste hot fluid to normal water, effectiveness is found to be 21.10%–23.88%, 90.91%, 3.40%–29.45%, 3.40%–25.33%, respectively, for the coil side. TFHE is thus proposed for heating water and space simultaneously.

Modeling, simulating, and validating a novel three-fluid heat exchanger (TriCoil™) for a residential heating and air-conditioning system integrating water-based thermal energy storage

An experimentally-validated novel three-fluid fin-and-tube heat exchanger (TriCoil™) is proposed for water-based thermal energy storage integration with ducted split systems (DSS) for residential heating and air-conditioning applications. TriCoil™ was modeled and simulated considering three circuitry layouts. The simulations showed that the capacity of the considered coils varied from around 4.5 to 13 kW depending on the operational mode and circuitry layout. With the capacity range of the considered coils, TriCoil™ can be a replacement to an A-shape indoor coil of DSS considering its dimensions with respect to its capacity. Also, fin density and thickness effects on TriCoil™ were investigated to improve its performance. For charging TES mode, the capacity increases by around 95% by increasing the Fin-Tube Ratio by 11%. For modes other than the charging mode, the change in the capacity mostly follows the trend of the air-side effectiveness when changing fin density and fin thickness; the capacity is more responsive to increasing fin density than increasing fin thickness. The TriCoil™ model was validated experimentally for different operational modes, and the average mean absolute error (normalized bias error) among different operational modes compared to the experimental data was 1.3% (0.17%) for the R410A side, 4.2% (-3.03%) for the water side, and 1.4% (-0.03%) for the air side.

Optimization of inserted coiled tube three-fluid heat exchanger using genetic algorithms

The three-fluid heat exchanger is a multi-stream heat exchanger that provides three streams at different temperatures for certain usage objectives. Recently, optimizing heat exchangers generally and three-fluid heat exchangers especially have received great attention in the energy field. The current study objective is to get the optimal mass flow rate of the three streams to minimize the entropy generation number and maximize effectiveness. Optimization is performed on the inserted coiled tube type for 24 cases with different usage objectives and different mass flow rate constraints. The optimization is done using an analytical approach for the temperature profiles and a regressed model for the overall heat transfer coefficients. Single-objective and multi-objective genetic algorithms are the optimization algorithms. The result shows that cooling the hot fluid is the most efficient usage objective; however, heating the intermediate-temperature fluid is the less efficient usage objective. Also, the study shows that the entropy generation number is dependent on the mass flow rate constraint. The maximum effectiveness of 0.693 occurs when the usage objective is cooling the hot fluid. In this case, the mass flow rate of the cold and the intermediate-temperature fluids are maxima while the mass flow rate of the hot fluid is minimum. The minimum entropy generation number 0.0486 occurs when the mass flow rate of the cold fluid is maximum while the mass flow rate of the hot fluid and intermediate-temperature fluid are minimal.

Multi-criteria assessment and optimization of a natural gas-fed solid oxide fuel cell combined heat and power system

Solid oxide fuel cell (SOFC) combined heat and power (CHP) system is a promising candidate for efficient power generation. Due to its complex dynamic characteristics, system performance is still unsatisfied when it operates in variable load conditions. In this study, five improved layouts of a natural gas-fed SOFC-CHP system are proposed using three-fluid heat exchangers innovatively. Performance of the system under different layouts is compared from both energy and exergy perspective and their feasibility in multi-load conditions is evaluated. Sensitivity analysis of four key parameters is conducted to clarify their influences and potential ways for efficiency improvements from both system and component level are explored under different load conditions. Results show that the system with direct combustion of anode off-gas has better adaptability to multi-load conditions. Exergy loss of the combustor always occupies the highest proposition among all the components, at least 30%. Because of the large thermal load and high outlet temperature of the cold fluid, thermal management of the reformer is crucial for the system operation. Changes of the reforming temperature and fuel utilization ratio significantly affect the system performance. As the load increasing, the electric efficiency decreases and the thermal efficiency increases, the total efficiency can always be more than 85% for the SOFC-CHP system.

Experimental investigation of a regenerative organic Rankine cycle (ORC) under different cryogenic cooling conditions

ABSTRACT This study experimentally investigates a Regenerative Organic Rankine Cycle (RORC) system that operated under varied cryogenic conditions using liquid nitrogen (LN2) as the heat sink. A three-fluid heat exchanger (TFHE) is applied to this system instead of a condenser and regenerator to realize the RORC system. The condensing pressure changes between 0.08 MPa and 0.6 MPa, and applying the R290 as the working fluid. The condensing pressure effect on system performances, including electrical power output, cold thermal efficiency, and exergetic efficiency, are investigated under different LN2 flow rates. The comparisons between basic ORC (BORC) and RORC under the same working conditions are conducted. The results demonstrate that as the condensing pressure remains constant, the higher LN2 flow rate is beneficial to the overall performance of the RORC system. The maximum cold thermal efficiency and power generation obtained in the RORC system are 13.35% and 738.81 W, which are obtained at the LN2 flow rate of 120 kg/h and the condensing pressure of 0.25 MPa. Additionally, the RORC shows improved performance with an exergetic efficiency of 10.68%. The results would be a technological guide for the construction and improvement of the system with cold energy recovery.

Energy and exergy analysis of a novel direct-expansion ice thermal storage system based on three-fluid heat exchanger module

Direct-expansion ice thermal storage (DX-ITS) system can overcome the mismatch between cold energy supply and demand, and also exhibit the characteristics of high energy efficiency, simple pipeline and minimal installation space. However, existing DX-ITS failed to achieve simultaneous high-efficiency heat transfer in the processes of charging and discharging, thereby limiting its widespread use. This study developed a novel DX-ITS system based on three-fluid heat exchanger modules employing micro heat pipe arrays to address the proceeding issue. Temperature distribution, pressure, charging and discharging power, energy efficiency ratio, exergy efficiency and ice packing factor during the charging and discharging processes at different compressor speeds, cooling-air temperature and flow rates were experimentally studied. Results demonstrated that maximum charging power, energy efficiency ratio, exergy efficiency, ice packing factor and discharging power of proposed system using a 4 HP compressor under experimental conditions reached 5.71 kW, 2.31, 11.12 %, 82.1 % and 4.99 kW, respectively. Moreover, cooling-air temperature had a more significant effect on system performance compared with cooling-air flow rate and compressor speed. The 11.7 %, 25.9 %, 24.3 %, and 20.6 % reductions in charging power, energy efficiency ratio, exergy efficiency, and ice packing factor were observed with an increase of cooling-air temperature from 18 °C to 35.5 °C.

Energy-efficient air conditioning system using a three-fluid heat exchanger for simultaneous temperature and humidity control

Room air conditioners are unable to simultaneously control the temperature and humidity of the air supply. Although temperature-regulating dehumidifiers can simultaneously control the temperature and humidity, they have complex refrigerant pipelines, and the heat exchanger exhibits air resistance when the reheat demand is low. This study proposes an air conditioning system for simultaneous temperature and humidity control, using a three-fluid heat exchanger. The supply air temperature is adjusted by changing the air volume ratio and cooling water flow rate through the three-fluid heat exchanger, which is used as the condenser. Free cooling can be realized by supplying low-temperature cooling water to treat the return air. Numerical models were built to simulate the performance of the devices in the system, and were validated by experimental results. The temperature-regulating performance and energy consumption under different conditions were numerically calculated using a case-studied air-conditioned room in Beijing. The results are summarized as follows: 1. The proposed strategy can regulate the supply air temperature over a wide range of temperatures. 2. Compared with those of the temperature-regulating dehumidifier system, the compressor and fan energy consumption of the proposed system are reduced by 19.1% and 15.5%, respectively, with a total energy-saving rate of 15.8% in the cooling season. 3. Compared with those of the room air conditioner system, the compressor energy consumption of the proposed system is reduced by 11.5%, and the energy-saving rate of the entire system is 6.3%. The initial investment of the proposed system does not increase significantly compared with conventional systems, and the refrigerant pipeline and valves can be simplified, resulting in acceptable economic performance for the proposed system.

Investigation on cross-flow three-fluid compact heat exchanger under flow non-uniformity: an experimental study with ANN prediction

ABSTRACT Non-uniformity in flow is the veritable situation in the case of heat exchangers and a decisive aspect of the design of heat exchangers. The extensive experimental investigation is ushered for compact three-fluid heat exchanger with cross-flow configuration under three distinct flow non-uniformities at the inlet of central fluid. The maximum augmentation of 3.4% in cooling efficacy is marked for and configuration under (flow non-uniformity type 3) condition. Artificial neural network (ANN) prognosis is perpetrated and the thermo-hydraulic efficacy is more accurately predicted by ANN configuration 3-4-4 under flow non-uniformity with an absolute fraction of variance almost equal to one.

The impact of ambient heat ingression on performance of cryogenic three-fluid cross-flow compact heat exchanger

The upshot of the improper insulation of the thermal system is the substantial instability and degradation in the thermal effectivity. The heat interaction between the ambient and heat exchanger shroud is initiated due to insufficient insulation, poor insulating material and/or the deterioration of the insulation over time. The dynamic investigation of the compact three-fluid heat exchanger (3-FHE) with cross-flow configuration (C1,2,3and4) under ambient heat ingression (both non-uniform and uniform) is conducted. The ‘Implicit Finite Difference’ scheme is implemented to perceive the numerical solution which is followed by experimentation to check the authenticity of the solution. Additionally, the ‘Dankwert's boundary condition’ which signifies the dispersive heat conduction in the fluids at the inlet section of the core and along the flow length; all along with the conduction of heat longitudinally in the exterior and parting walls is involved which has come up as the most practical model. It is learnt that the expeditious attainment of steady-state is observed under ambient heat ingression. It is engrossing to mention that the axial dispersion (AD) and longitudinal heat conduction (LHC) escorts in lower deterioration in cooling effectivity by 20.22% and 9.14% respectively under ambient heat ingression. The C1 configuration offers maximum drop of 41.8% in thermal effectivity under the varying magnitude of uniform heat ingression factor from 1 to 10. The adjacent fluids which are adhered to the non-insulating exterior wall reflect considerably early ‘temperature cross’ with the central hot fluid.

Condensation heat transfer performance in multi-fluid compact heat exchangers with wavy and strip fins

The effect of different geometrical parameters of wavy and strip fins in a three-fluid plate-fin compact heat exchanger on the condensation heat transfer in the middle heat exchanger has been experimentally investigated. The three-fluid heat exchanger consisted of three heat exchangers with strip and wavy fins. In the examined system, the hot and cold fluids flowed through the adjacent heat exchangers (strip channels), while the middle heat exchanger (wavy channels) was occupied with a single-component two-phase flow (condensed vapor). The Nusselt number, the friction factor, the heat transfer surface contribution between the middle heat exchanger and each of the adjacent heat exchangers, and the thermal performance factor were calculated using the measured data at the inlets and outlets of the heat exchangers, and by using the thermal balance equations between the fluids passing through the heat exchangers. In the examined heat exchanger, the hot and cold flows had a cross-direction with the two-phase fluid flow. The two-phase Reynolds number, the vapor quality, and the heat transfer surface contribution of the middle heat exchanger with the adjacent heat exchangers were 50–4800, 0.1–0.67, and 0.19–0.7, respectively. The results show that the two-phase flow pattern in the wavy channels of the middle heat exchanger is stratified and wavy. According to the findings, a higher thermal performance factor is observed when the ratio of the wavy channel heat transfer surface to the heat transfer surface of the cold or hot flows is closer to 1. Also, with higher wave amplitude to wavelength ratios, lower pitch to height ratio of the fins, the lower wavelength to the fin length ratios, and lower fin pitch to wave amplitude ratios are obtained a higher thermal performance factor.

Enhanced effectiveness with positive Joule–Thomson pressure drop effects on a cryogenic heat exchanger with three fluid-two communications

PurposeThe purpose of this paper is to attain higher effectiveness with an introduction of Joule–Thomson effect on a three-fluid heat exchanger with two communications. It also gives a range of parameter values that have to be maintained for achieving effectiveness above 0.85. Attaining effectiveness above 0.85 is very important for the heat exchanger to perform the liquefaction of hot fluid.Design/methodology/approachThe analysis is conducted using Galerkin’s method, a finite element approach.FindingsThis investigation determines crucial values for the cryogenic heat exchanger to achieve effectiveness above 0.85. The important findings are as follows: effectiveness above 0.85 is attained if the heat exchanger size is within the range of 8–10; ratio of heat flow resistance between intermediate and hot stream to heat flow resistance between cold and hot stream should be maintained between 1 and 10; the intermediate fluid temperature should be maintained between 0 and 0.2; the ratio of thermal capacity of the hot fluid relative to a cold fluid should be maintained between 1.25 and 1.42; and the ratio of thermal capacity of the hot fluid relative to an intermediate fluid should be maintained between 2 and 2.5.Research limitations/implicationsThe investigation has presented a finding for improving the effectiveness of the cryogenic heat exchanger. Higher the Joule–Thomson pressure drop effect, more is the drop in temperature of the fluid resulting in additional cooling or lowering of the fluid temperature. The practical implementation is also explained, i.e. to achieve practically the Joule–Thomson pressure drop in a cryogenic heat exchanger.Originality/valueTo the best of the authors’ knowledge, no investigations were carried out previously on Joule–Thomson investigation on a three-fluid heat exchanger with two communications, for different values of Joule–Thomson pressure drop.

Experimental investigation of the thermal performance in a single-component two-phase flow in multistream multi-fluid plate-fin heat exchangers

This paper focuses on evaluating the effects of flow rate and temperature changes of hot and cold fluid flows in multistream multi-fluid plate-fin heat exchangers with a single-component two-phase flow in the middle heat exchanger. This three-fluid heat exchanger included three layers with offset strip and wavy fin configurations. In the adjacent heat exchanger with offset strip fins, hot and cold fluids were flowing, while the middle heat exchanger with wavy fins contained a single-component two-phase flow (condensed vapor). The Nusselt number, friction factor, the thermal performance factor, and the heat transfer surface contribution of the middle heat exchanger with each of the adjacent heat exchangers, were obtained using the measured experimental data. The results indicate that the two-phase Reynolds number was between 500 and 1800, and the vapor quality varied in the range of 0.17–0.56. Also, the heat transfer surface contribution of the adjacent cold and hot fluids was between 0.18 and 0.5. The two-phase flow in the wavy channel has a wavy and stratified pattern. The examinations showed that raising the Reynolds number of hot and cold fluids, respectively, led to maximum 13.8 % and 9.5 % of reduction in the vapor quality, 8.8 % and 9 % of increase in the two-phase Nusselt number, and 18 % and 12 % of reduction in the average value of friction factor. The domain change in the two-phase vapor quality, the two-phase fluid heat transfer surface contribution, and the flow pattern determination parameters including the dimensionless mass parameter and the Lockhart-Martinelli parameter was 33.67 %, 80.81 %, 32.72 %, and 19.09 %, respectively. As the Reynolds number of the cold fluid was changed, the variation domain of these parameters was higher compared to when the Reynolds number of the hot fluid was altered. Increasing the dimensionless temperature of the hot and cold raised the vapor quality by 12–16 %. The experimental results revealed that by decreasing the temperature of adjacent fluids and increasing their Reynolds number, the thermal performance factor of the two-phase flow was increased.

Experimental investigation on the thermal performance of inserted helical tube three-fluid heat exchanger using graphene/water nanofluid

Experimental investigation on the thermal performance of inserted helical tube three-fluid heat exchanger using graphene/water nanofluid

Experimental investigation and ANN modelling on thermo-hydraulic efficacy of cross-flow three-fluid plate-fin heat exchanger

Compact cross-flow three-fluid heat exchanger with plain rectangular fins is experimentally investigated for both thermal and hydraulic efficacy under steady-state condition. The elaborative investigation is conducted for all the four viable flow arrangements of cross-flow configuration which comprises the effect of Colburn factor and effectiveness ratio of central and adjacent fluids, and friction factor with Reynolds number. It is learnt that thermal efficacy is sentient to the operating conditions, type of flow arrangement and variation in flow rate. The comparison of the efficacy between the plain duct (without fin core) and with fin heat exchanger core is presented to analyse the impact of fins in enthalpy exchange. The regression correlation is developed to estimate the thermal and hydraulic performance which are accurate within ±16% and ±5.8% respectively. The investigation is further assisted with the ANN modelling for the prediction of the thermo-hydraulic efficacy with two input (Reynolds number and flow arrangement type) and four output performance parameters (Colburn factor, friction factor and effectiveness ratios). The fraction of 77% and 23% of data is considered for training and testing the neural network respectively. It is learnt that ANN predictions are more promising and accurate than regression predictions and the magnitude of the value of an absolute fraction of variance equals unity.

Internally cooled membrane-based absorber for dehumidification and water heating: Validated model and simulation study

This paper presents a comprehensive model for advanced membrane-based absorber components accounting for three separate fluid streams, one of them providing internal cooling, with complex flow patterns. The model was implemented with various liquid desiccants and their properties (including LiCl, CaCl2, and [emim][OMS] ionic liquid [IL]). The model has been validated using data from two laboratory prototype absorbers, one with CaCl2 as the working fluid and one with an IL as the working fluid. Entropy analysis was further carried out to verify the model and understand effect of internal cooling on the entropy variation of three fluid streams. The developed model and codes are expected to enable detailed configuration optimization and provide in-depth understanding of three-fluid heat and mass exchanger (HMX) performance. The paper also describes parametric studies of the HMX components in utilizing the latent heat removed in space cooling to heat water and numerically explores the unique benefit of its application in a semi-open absorption heat pump water heater. The results show that a single three-fluid HMX has the potential to achieve simultaneous dehumidification and water heating efficiently at cost effectiveness, particularly in hot and humid climates.

Experimental study and exergy analysis of three-fluid tubular heat exchanger with nanofluids

The present study investigates the exergetic performance of a three-fluid heat exchanger employing Al2O3-water nanofluids. Numerical and experimental approaches were applied to investigate the effects of varying flow rates, flow arrangements and nanoparticle volume concentrations on overall performance of the exchanger under study. Reynolds number in the range 2500-10,000 and volume concentration of nanoparticles in the range 0%-3% have been considered to study their effects for four flow arrangements. Numerical results revealed that increasing flow rate and addition of nanoparticles resulted in a reduction of exergy loss of the system. Significant deviation between experimental and numerical results was observed. At a maximum Re = 10,000, a drop in exergy loss by 23.7% for parallel, 11.56% for parallel-counter, 10.6% for counter-parallel, and 25.8% for counter flow arrangements by varying ϕ from 0% to 3%. Furthermore, minimum exergy loss for all the flow arrangements was found at φ = 3% and Re = 4500.

Experimental study and exergy analysis of three-fluid tubular heat exchanger with nanofluids

The present study investigates the exergetic performance of a three-fluid heat exchanger employing Al2O3-water nanofluids. Numerical and experimental approaches were applied to investigate the effects of varying flow rates, flow arrangements and nanoparticle volume concentrations on overall performance of the exchanger under study. Reynolds number in the range 2500-10,000 and volume concentration of nanoparticles in the range 0%-3% have been considered to study their effects for four flow arrangements. Numerical results revealed that increasing flow rate and addition of nanoparticles resulted in a reduction of exergy loss of the system. Significant deviation between experimental and numerical results was observed. At a maximum Re = 10,000, a drop in exergy loss by 23.7% for parallel, 11.56% for parallel-counter, 10.6% for counter-parallel, and 25.8% for counter flow arrangements by varying ϕ from 0% to 3%. Furthermore, minimum exergy loss for all the flow arrangements was found at φ = 3% and Re = 4500.

Detailed Design Optimization of Three-Fluid Parallel-Flow Plate-Fin Heat Exchanger Using Second Law Analysis

Abstract Compact parallel-flow three-fluid heat exchanger (TFHX) of plate-fin type is optimized for attaining the minimum entropy generation unit. Four different types of plate-fins (plain rectangular, offset strip, corrugated louvered, and wavy fin (WF)) which are embodied within heat exchanger have been selected for the study under both cocurrent and countercurrent flow arrangements. The range of the decision variables are 0.3≤ma, mb, mc≤3, 0.1≤Ø≤0.95, 0.1≤Lx, Ly≤2, 0.015≤H≤0.033, 100≤n≤700, 0.0001≤tf≤0.0002, 0.001≤l≤0.009, 0.01≤Lwav≤0.09, and 0.001≤A≤0.005. Genetic algorithm is selected as an optimization tool that is apt in handling various continuous and discrete variables and the problems with the complexities in the objective function as well as in constraints. Validation of the optimization model is carried out by comparing the optimum results with that obtained from the experiments, particle swarm optimization (PSO) (under without heat duty constraint), and graphical method (under with heat duty constraint). It is observed that for a specified heat duty (180 kW) and given operating conditions, corrugated louvered fin (CLF) with countercurrent flow arrangement offers the minimum entropy generation among all. It is riveting to learn that the optimum results occur for most of the considered cases when the flowrate of the central hot fluid is lower than that of the adjacent fluids. At fixed Re = 3000 for all the fin types, off-set strip fin is the most favorable one, and plain rectangular fin (PRF) offers the worst solution comparatively.