Heat Exchange Efficiency Research Articles

Thermo-mechanical behavior of steel pipe energy piles under thermal imbalance cycles

There is an effect on the thermo-mechanical behavior of the energy pile from the thermal imbalance conditions (heating with different amplitude than cooling). In this study, 5 cycles with a heating amplitude of 25℃ and a cooling amplitude of 15℃ were performed on ordinary concrete energy piles (OCEP), steel pipe concrete energy piles (SPEP), and steel pipe phase change energy piles (SCEP), respectively. The results show that imbalanced heating and cooling conditions alter the temperature distribution of the energy pile, causing irreversible displacement accumulation. However, including steel tubes reduces the loss of load bearing capacity caused by the heating and cooling cycles. The maximum increase in pile temperature was 6.7℃ for OCEP, 7.9℃ for SPEP, and 7.1℃ for SCEP. The final normalized displacement rates were −0.462 %, −0.558 %, and −0.515 %, respectively. The ultimate bearing capacity of the piles was reduced by 10 %, 9.1 %, and 9.1 %, respectively. The heat exchange efficiency of the 5th heating and cooling phases of SCEP increased by 67.4 % and 65 % compared to OCEP and by 26.3 % and 20 % compared to SPEP, finally stabilizing at 72 W/m and −66 W/m, respectively. This study provides a qualitative analysis of energy piles operating under heating and cooling imbalance conditions.

Design optimization of heat exchanger using deep reinforcement learning

A micronuclear reactor is currently being developed using 3D printing technology, with a focus on refining the design of its heat exchanger. The objective is to optimize the topology of heat exchangers to improve their performance. The initial thermofluidic topology design is a crucial factor influencing the efficiency of the final optimized heat exchanger. This paper presents a novel approach for the topology optimization of heat exchangers using initial designs generated via deep reinforcement learning (DRL). A printed circuit heat exchanger (PCHE) served as the target for this optimization. Extensive simulations demonstrated that the DRL-assisted optimization method enhanced the heat exchange efficiency by 14.8% compared with that of conventional topology-optimized PCHEs. The optimized heat exchanger was fabricated using 3D printing, and its feasibility was confirmed by comparison with simulation data. The integration of DRL into the topology optimization and production processes via 3D printing lays the groundwork for the development of more efficient thermal systems and demonstrates a viable method for complex engineering applications.

Modeling of Metal Matrix Concentrated Solar Receivers for sCO2 Power Blocks

Abstract Supercritical CO2 power blocks for Concentrating Solar Power (CSP) with novel metal matrix solar receivers have the potential to reduce operating expenses while improving overall system efficiencies. These concentrated solar receivers integrated with a metal matrix-based phase change (PCM) thermal storage medium provide the compounding effect of an efficient heat exchanger while also integrating thermal storage within the receiver. Detailed numerical modeling of such devices with enthalpy-porosity-based formulation for phase change and turbulent convective heat transfer for the sCO2 microchannels is described in the current work. With sCO2 power blocks operating at temperatures and pressures beyond 800°C and 200 bar, different high-temperature PCMs are studied. A detailed steady charging followed by discharge and charging transients is simulated to analyze the thermal performance of these devices. In the current work, the energy storage density of PCMs is studied, followed by an analysis of the movement of the melt-pool interface over the streamwise length of a high corrugation wavy microchannel. A scaling analysis is carried out to estimate the heat transfer coefficients while compare them with the numerical model predictions. The results from the current work can be utilized for sizing and detailed design of integrated solar receivers for high-temperature sCO2 power block applications.

Numerical analysis on the flow and heat transfer characteristics of heat exchanger with cruciform tube

The heat exchanger (HE) is widely used in energy and power industries, which has a vital impact on the stability and efficient operation of relevant industrial systems. Different shaped heat exchange tubes are often designed specially to improve the thermal–hydraulic efficiency of HEs. In the study, two new geometries named the cruciform twisted tube and cruciform straight tube are introduced, and the heat & mass transfer properties of liquid lead (Pb) and supercritical carbon dioxide (s-CO2) in the HEs are numerically studied to assess the thermal–hydraulic efficiency and application prospect of two kinds of cruciform tube HEs. The results demonstrate that the unique cross-section geometry of the cruciform tube improves the uniformity of the flow field, and the spiral structure of the cruciform twisted tube effectively improves the blending and turbulence of working fluid. The cruciform tube can improve the comprehensive performance of the HE by more than 12%.

Effect of fluid direction and reactor structure on heat storage performance of Ca(OH)2/CaO based on shell-tube thermochemical energy storage device

The flow direction of the heat transfer fluid (HTF) and reactor structure inside the shell-tube heat exchanger has a significant impact on the heat transfer performance of the shell-tube reaction device. In this study, a comprehensive 3D multi-physics coupled model of a shell-tube fixed bed thermochemical energy storage (TCES) device is developed. The investigation delves into the influence of HTF flow direction and reactor structural design on a plethora of critical parameters including temperature distribution, steam pressure distribution, reaction extent, reaction time, heat transfer power, heat transfer efficiency, and heat storage efficiency within the reactor. The result indicates that the flow direction of HTF has an impact on the homogeneity of the reaction in the tube, and the countercurrent and concurrent flow can realize the gradient and homogeneous occurrence of the reaction in the tube, respectively. Both lessening the outer diameter of the device and increasing the diameter of the heat storage material filling tube can improve the average heat exchange efficiency and the average heat storage efficiency. Compared with the basic case (Basic case A), the optimized (Case D) heat storage device volume decreased by 13.38 %, the energy stored amount increased by 24.14 %, heat storage time shortened by 8.04 %, and heat storage efficiency increased by 32.14 %. Additionally, the inlet temperature and velocity still have an obvious influence on the thermal performance of the reactor after structural optimization. These research findings guide for improving the heat and mass transfer effect and working performance of the shell-tube fixed bed Ca(OH)2/CaO reactor.

EduSolar: A Remote-Controlled Photovoltaic/Thermal Educational Lab with Integrated Daylight Simulation

This study presents a compact educational photovoltaic/thermal (PV/T) system designed for thorough performance assessment under simulated weather conditions. As an affordable educational tool, the system offers significant pedagogical value. The PV/T system features two photovoltaic modules: a thermally enhanced module and a standard one. The thermally enhanced module uses water as a coolant, which transfers heat from the PV cells to a fan-operated heat exchanger, with the coolant being recirculated to maintain optimal conditions. A halogen lamp, placed between the modules, simulates solar radiation to ensure effective electrical current generation. The system’s remote-control capabilities, managed via the Message Queuing Telemetry Transport (MQTT) protocol, enable real-time adjustments to the coolant flow rate, heat exchanger efficiency, and lamp brightness, as well as monitoring of electrical parameters. Experimental findings indicate that the PV/T module achieves a 7.71% increase in power output compared to the standard PV module and offers a 17.41% improvement in cooling efficiency over scenarios without cooling. Additionally, the numerical methods used in the study show a maximum deviation of 4.29% from the experimental results, which is considered acceptable. This study showcases a best practice model for solar training, applicable from elementary to university levels, and suggests innovative approaches to enhancing solar energy education.

Entropy generation analysis for designing efficient and sustainable heat exchangers and chemical reactors: From 1D modelling to detailed CFD simulations

Entropy Generation Modelling (EGMod) is the topic dealing with the calculation of entropy sources in real processes. It is gaining ground since the entropy generation rate aggregates all irreversibility sources through a meaningful combination allowing to evaluate the energy-efficiency and sustainability of a given operation. Several EGMod approaches are reported in literature and are based on 1D process models or CFD simulations. 1D models are the most used given their computational efficiency, however, no study has compared their performances to CFD yet. In this paper, EGMod approaches are compared through three case studies highlighting their potentials and limitations. The results reveal that, although 1D approaches can correctly determine the temperature and concentration profiles along the process, they inherently lead to significant errors in the calculation of the entropy generation rate. These errors become important in the presence of chemical reactions as they lead to intercorrelation between local temperatures and concentrations.

Flue gas-dust two-phase heat transfer characteristics and corrosion behavior in industrial-scale waste heat boilers

Waste heat boiler (WHB) has been extensively utilized across various industries due to the high efficiency in heat recovery and robust adaptability. This study employs the multiphase particle-in-cell approach to investigate the heat transfer behavior between flue gas and dust, as well as the in-furnace corrosion behavior in an industrial-scale WHB. Upon validation of the model, the flow dynamics of flue gas, the distribution characteristics of dust particles, corrosion behavior together with the effect of structure are examined. The findings reveal that excessive vortex formation significantly disrupts the flow uniformity of flue gas, with 0.87 % of the particles backflowing into the rising flue, and 51.6 % of the particles settling in the WHB. The heat transfer coefficient of dust particles reaches its peak at velocities ranging from 2 to 4 m/s, with a maximum value of 204 W/(m2K). Increasing the baffle spacing diminishes the vortex intensity in the radiation chamber and improves the flow uniformity of flue gas. Expanding the radiation chamber size not only enhances the heat exchange efficiency of flue gas, resulting in a temperature decrease of 24 K at the chamber exit, but also increases the particle sedimentation rate by 3.1 %.

Statistical investigation of heat transfer efficiency on a ternary nanoflow over a stretching surface

Ternary hybrid nanofluids offer significant advantages in heat transfer due to their enhanced thermal conductivity compared to traditional fluids. Investigating their flow behavior over expanding surfaces can contribute to the development of more efficient heat exchangers and cooling systems in the electronics, energy production, and transportation industries. This paper presents a detailed analysis of the flow and thermal transfer characteristics of a ternary hybrid nanofluid (SiO2–Cu–Al2O3/H2O) over a radially stretching surface, utilizing both numerical techniques (Keller Box method) and statistical techniques. Furthermore, the model includes factors like convective heat transport, radiation, internal fluid friction, and suction. Similarity transformations transform the governing equations for fluid flow and heat transfer into a system of nonlinear ordinary differential equations. Then the equations are solved numerically using the Keller Box method with the aid of MATLAB software. Additionally, we have employed statistical techniques such as correlation analysis, probable error estimation, and multivariate regression to validate and ensure the accuracy of the numerical outcomes. Parameter ranges for Biot number, radiation, unsteadiness, Eckert number, and energy generation parameter are 0.1 ≤ Mp ≤ 0.7, 0.1 ≤ Ks ≤ 1.5, 0.2 ≤ Ps ≤ 0.8, 0.1 ≤ EN ≤ 0.4, 0.5 ≤ RN ≤ 2, 1≤ BT ≤ 2.5, 0.1 ≤ Hsc ≤ 0.7 and found to significantly impact heat transfer behavior within these bounds. This study utilizes 3D surface plots to visualize the influence of key parameters on engineering quantities. R squared values show that the data strongly match the regression model. The findings demonstrate excellent concordance between the predicted values and the actual Nusselt number and skin friction measurements. Biot number has a very strong correlation with heat transfer, with minimal chance of error. And the same is evidenced by the correlation matrix and multiple regression analysis. Eckert number also exhibits a negative correlation with the Nusselt number. This translates to a situation where increasing Eckert number directly leads to a decrease in the rate of heat transfer, with no margin for error. Energy generation parameter demonstrates a negative correlation with heat transfer. However, there's a slight possibility of error, with an estimated error percentage of around 0.0017.

Analysis of entropy generation and MHD thermo‐solutal convection flow of Ellis nanofluid through inclined microchannel

AbstractThis study investigates heat, mass transport, and entropy production in Ellis nanofluid flow through an inclined permeable microchannel, considering Navier's slip effects with convective boundary conditions. It incorporates nanoparticle's thermophoresis and Brownian motion effects under a transverse magnetic field, with fluid suction and injection at microchannel walls. Under appropriate physical assumptions, the problem is presented as nonlinear ordinary differential equations, which are later nondimensionalized. The MATLAB bvp4c solver is used for numerical solutions of the transformed equations. Graphical depictions in the study illustrate how various factors influence velocity, temperature, concentration, Bejan number, and entropy generation. Engineering parameters, affected by changes in critical factors, are presented in tabular format, including the skin friction coefficient, Nusselt number, and Sherwood number. Notably, the enhancement in Ellis fluid parameter has a dual effect, enhancing velocity and Bejan number in the microchannel's lower half, while reversing in the upper half. For the increment in Ellis parameter, the impact on Bejan number for 0.5 is significant and the effect on entropy production contrasts with that of Bejan number. This research offers practical insights for designing efficient microfluidic heat exchangers and developing advanced nanofluids for improved thermal performance while minimizing entropy generation. Additionally, it underscores the potential for innovation within the domain of microfluidics and nanomaterial‐driven heat transfer systems. Furthermore, it should be noted that the flow behavior of Ellis nanofluids within microchannels can closely replicate natural flow patterns found in biological systems, offering insights that could have numerous applications in biology and related fields.

The effects of bioconvection, non‐Fourier heat flux, and thermal radiations on Williamson nanofluids and Maxwell nanofluids transportation with prescribed thermal conditions

AbstractThe utilization of nanoentities in common fluids has opened new opportunities in the area of heat transportation. The rising requirements to enhance the efficiency of compact heat exchangers can be achieved by using various nanofluids. In this article, the thermal output of Maxwell and Williamson nanofluids transport over a prolonging sheet with bioconvection of self‐motivated organisms is scrutinized. A magnetic flux and the porous effects of a medium influence the flow of fluids. The fundamental principles for conservation of mass, concentration, momentum, and energy yield a nonlinear set of partial differential equations that can then be altered into ordinary differential form. A heat transfer flux is presented along with temperature boundary conditions, PST, and PHF (prescribed surface temperature and prescribed heat flux). The numerical results are acquired by executing the Runge–Kutta method with a shooting procedure in MATLAB coding. By fluctuating the inputs of influential variables of the dependent functions, a precise overview of the scheme is acquired. It can be seen that velocity decreases with the rising values of buoyancy ratio, magnetic force, Raleigh number, and porosity. Also, the temperature of the fluids begins to rise directly with the rising values of thermophoresis and Brownian motion parameters. The present study addresses bioconvection, non‐Fourier heat flow, and thermal radiations while combining the special properties of Williamson and Maxwell nanofluids. The field of biomedical engineering may benefit from this study, particularly with regard to therapies for hyperthermia and drug delivery systems. This study can be useful in cutting‐edge cooling systems, bioengineering, solar energy conversion and biotechnology.

Maximizing thermal performance in triangular honeycomb thermochemical reactors: Structural and operating parameter studies

Using thermochemical energy storage methods to store energy is increasingly vital for boosting the share of renewable energy in consumption within buildings and industries. This entails harnessing off-peak excess renewable energy, such as electricity or waste heat energy, for storage purposes. While previous research emphasizes the importance of improving reactor performance, comprehensive analysis of the new honeycomb reactor designs is lack. Innovative advancements in maximizing thermal performance within triangular honeycomb reactors are elucidated in this study. This study employs a validated 3-D model to explore the effects of these parameters on heat and mass transfer within a triangular honeycomb reactor. By investigating structural and operational parameters, a novel equilibrium is achieved, amplifying heat exchange efficiency and channeling thermal energy with unprecedented precision. Through a rigorous examination of reactor air velocity distribution, air temperature lift, and outlet air absolute humidity, this research unveils pivotal insights into enhancing reactor efficacy. Notably, the study identifies that increasing the channel thickness by 1.2 times, resulting in energy storage density of 463 kJ/kg. This innovation positions triangular honeycomb reactors at the forefront of sustainable energy management, offering a potential solution for decarbonization such as storing industrial waste heat and harnessing surplus off-peak electricity in buildings.

Comparative analysis of entropy generation in smooth and micro-fin tubes using R513A refrigerant: A parametric study

Currently, although significant advancements have been made in understanding heat transfer coefficients and pressure decreases in different tube shapes, there is still a noticeable lack of detailed studies on the generation of entropy under flow boiling conditions. In this work, the entropy generation in micro-fin tubes (MFT1 and MFT2) and smooth tubes (ST1 and ST2) in flow boiling conditions experimentally investigated with refrigerant R513A. Research focused on evaluating influence of different input parameters on entropy generation, specifically contribution of heat transfer coefficient (HTC) and total pressure drop (TPD) on entropy generation for all testing tubes. As at a heat flux of 6 kW·m−² and a saturation temperature of 12 °C, MFT1 shows HTC contributions to entropy generation ranging from 0.032 to 0.156 W·K−1, while MFT2 ranges from 0.03 to 0.14 W·K−1. TPD contributions for both MFT1 and MFT2 range from 0.001 to 0.04 W·K−1. Hence, MFT2 shows better results than MFT1 as low entropy generation required for a good heat exchanger. Among input parameters, heat flux displays the highest sensitivity, indicating its significant influence on total entropy generation variations, while vapor quality, mass flux, and saturation temperature also demonstrate notable sensitivity. This research helps us design systems that transfer heat more effectively while using less energy. Understanding these factors can lead to more efficient heat exchangers and other thermal systems.

Enhancing heat exchanger performance with perforated/non‐perforated flow modulators generating continuous/discontinuous swirl flow: A comprehensive review

AbstractHeat exchangers are crucial in transferring heat and finding applications across various industries. Numerous strategies have been devised to improve and optimize the heat transfer process within these systems. Among these, passive methods have garnered significant attention for their ability to operate without external power consumption. This article examines the recent experimental and computational studies conducted by researchers since 2018 on passive enhancement techniques, especially twisted tape, wire coil, swirl flow generator, and others, to boost the thermal efficiency of heat exchangers and aid designers in adopting passive augmentation methods for compact heat exchangers. Recently, researchers' new class of flow maldistribution devices, referred to as swirl flow devices, has gained attention; which enhances convective heat transfer by introducing swirl into the main flow and disrupting the boundary layer at the tube surface through alterations in surface geometry. Twisted tape inserts are devices that demonstrate better performance in laminar flow compared to turbulent flow. Conversely, other passive techniques like ribs, conical nozzles, and conical rings are generally more effective in turbulent flow than laminar flow. A recent research trend is the utilization of nanofluids in combination with other passive heat transfer enhancement techniques like turbulators, ribs, and twisted tape inserts in heat exchangers, which can reduce exergy losses and improve overall convective heat transfer coefficient and effectiveness of heat exchanger.

A correlation for U-value for laminar and turbulent flows in concentric tube heat exchangers

This paper introduces a novel empirical correlation designed to predict the overall heat transfer coefficient (U) in concentric tube heat exchangers. The study utilizes a comprehensive dataset of 2700 data points from CFD simulations, examining the impact of critical variables including hot and cold fluid Reynolds numbers (Reh, Rec), Prandtl numbers (Prh, Prc), and heat exchanger dimensions (tube hydraulic diameter Dh, annular space hydraulic diameter Dc, and overall length L). The analysis incorporates a range of fluid combinations in the tube and annular sections – air–air, air–water, water-air, and water–water – across Reynolds number ranges from 1000 to 20000, covering both laminar and turbulent flow regimes. The correlation was developed using the Adam optimizer to minimize the Weighted Mean Squared Error (WMSE), achieving an impressive convergence to an average prediction error of 6.7% compared to actual U values. The model categorizes flow into four distinct categories, each corresponding to a combination of flow patterns in the tube and annular spaces regimes – Laminar–Laminar, Laminar–Turbulent, Turbulent–Laminar, and Turbulent–Turbulent – integrating both hydrodynamic and thermal entry effects to enhance prediction accuracy. Rigorous error analysis revealed a median error of 5.18%, substantially outperforming existing models. Notably, 10% of the predictions deviate by less than 1%, with 90th percentile errors staying below 15%. Parameters were finely tuned through extensive numerical simulations, ensuring accurate application of the correlation across diverse operational conditions. The study concludes by highlighting the model’s potential to significantly enhance the design and efficiency of heat exchangers and proposes future enhancements to further improve its predictive accuracy.

Stereoscopic Micro-PIV measurement of the flow dynamics in a spherical dimple

One way to increase the thermal efficiency of heat exchangers is to structure the heat transfer surfaces with dimples, resulting in an enlarged surface area and intensified turbulence in the fluid flow. The increased turbulence also causes higher wall shear stress, which potentially suppresses the deposition of particles and supports a self-cleaning of the surface. For a deeper understanding of these phenomena, the flow dynamics inside the dimple were observed experimentally with Stereoscopic Micro-Particle Image Velocimetry (Stereo µPIV). The formation of an unsteady oscillating vortex, which leads to an asymmetric trail downstream of the dimple, is visualized. The significant influence of the dimple geometry on heat transfer enhancement is shown, and the most beneficial geometric ratio of the spherical dimple regarding its ability to increase turbulence is identified. A comparison of the local flow velocities with the results of the numerically and experimentally observed patterns of the deposited particles caused by the dimple’s self-cleaning effect shows a good match.

Heat transfer characteristic of an alumina oscillating heat pipe

Oscillating heat pipes (OHP) are a promising and highly efficient heat transfer technology especially in the field of power electronics thermal management. However, conventional metal OHP do not meet the need for insulation or low coefficients of thermal expansion. In order to expand the application field and break the application limitation of the OHP technology, alumina ceramic oscillating heat pipes was designed and investigated in this paper. The alumina OHPs combine the excellent insulating, oxidation-resistant, corrosion-resistant and low thermal expansion properties of alumina ceramic with the efficient heat exchange mechanism of oscillating heat pipe technology, exhibiting great application potential. An alumina flat-plate oscillating heat pipe was prepared, 6 internal microchannels were examined using micro-CT, and the microstructure was characterized using scanning electron microscopy. The heat transfer characteristics of the OHP charged with water were investigated using a heat transfer test system. Increasing heat loads were employed to the OHP, and the operating temperature of 20 °C and 60 °C as well as the orientation varied between 0° and 90° were also introduced. The oscillation motion of the alumina OHPs were investigated, including temperature oscillations before and after startup of the OHPs, and a comparison effective thermal conductivities at various tilt angles and operating temperatures was carried out. The experimental results revealed that the heat transfer performance of the alumina oscillating heat pipe significantly increased with the increased heat loads and reached to 861.7 W/(m∙K) at 56 W. The effective thermal conductivity of the OHP was 6 times higher than that of the empty OHP at heat load of 16 W. When the orientation was 30°, the temperature oscillation instability increased, the oscillation amplitude increased, and the heat transfer performance of the oscillating heat pipe decreased. As the operating temperature increased, the stability of temperature oscillations improved, the amplitude decreased, and heat transfer performance was enhanced.

Study of heat transfer and hydrodynamic processes in a full-size thermosyphon installation under the influence of solar radiation with coolant

Abstract This article discusses the theoretical background and results of the study of heat exchange and hydrodynamic processes occurring in a thermosiphon installation. One of the important characteristics of the operation of thermosiphons is their ultimate heat transfer capacity, the calculation of which allows us to create a reliable, highly efficient heat exchange device. For optimal design and improvement of the technical and economic indicators of a thermosiphon installation, it is necessary to develop and improve scientifically based methods for calculating the processes occurring in the elements of its design. The purpose of the experimental part of the work was to test the selected theoretical model and more accurately determine the physical picture of the processes occurring in full-scale thermosiphon installations by measuring not only integral, but also local characteristics of the installation. There is intense heating of the liquid in the collector in the first half of the day (from 11 to 13 hours) and a slowdown in the rate of increase in temperature at the outlet of the collector in the second half of the day. A drop in the level of solar radiation in the second half of the day does not lead to a significant decrease in the temperature at the outlet of the collector, which is obviously explained by an increase in the temperature of the liquid at the inlet to the collector during the period under consideration. The presence of a long period of lag in the increase in the temperature of the liquid at the inlet to the collector compared to the temperature at the outlet is associated with the inertia of thermal processes in the system. The time interval from the beginning of the experiment to the beginning of the increase in the temperature of the liquid at the inlet to the collector coincides with the period of a single circulation of the liquid in the system.

Comprehensive Performance Analysis of Hybrid Solar Water Heating Systems: Synergizing Photovoltaic and Thermal Technologies

Abstract: Solar water heaters are an efficient and sustainable technology for meeting the growing demand for hot water in residential and commercial applications. This abstract presents a comprehensive overview of the performance evaluation of solar water heater systems through an extensive experimental study. The study aims to assess the effectiveness and efficiency of different solar water heater configurations under varying operating conditions. The experimental investigation involved the measurement and analysis of key performance parameters such as solar collector efficiency, heat transfer efficiency, thermal storage capacity, and overall system efficiency. A range of factors including solar radiation intensity, ambient temperature, water flow rate, and collector tilt angle were systematically varied to examine their impact on system performance. The results of the experimental study demonstrated the significant potential of solar water heaters in providing cost-effective and environmentally friendly hot water solutions. The solar collector efficiency was found to be highly influenced by the solar radiation intensity, with higher levels of solar irradiation leading to increased thermal energy generation. The heat transfer efficiency was optimized by adjusting the water flow rate and collector tilt angle, ensuring efficient transfer of heat from the collector to the water. Furthermore, the thermal storage capacity of the system played a crucial role in maintaining a consistent supply of hot water during periods of low solar radiation or high demand. Overall system efficiency was found to be strongly dependent on the integration of efficient heat exchangers and insulation materials. Based on the experimental findings, recommendations for system design and optimization were formulated, highlighting the importance of proper sizing, selection of suitable materials, and appropriate control strategies. The results also identified areas for future research, such as the integration of advanced heat transfer enhancement techniques and the utilization of hybrid solar water heater systems

A Comprehensive Evaluation of Recent Studies Investigating Nanofluids Utilization in Heat Exchangers

This comprehensive review critically examines recent research concerning the application of nanofluids in heat exchangers. The utilization of nanofluids, which are colloidal suspensions of nanoparticles in a base fluid, has garnered significant attention in enhancing heat transfer performance. Various studies have explored the potential benefits and challenges associated with incorporating nanofluids into heat exchanger systems. Through a systematic analysis of recent literature, this review assesses the effectiveness of nanofluids in improving heat transfer efficiency and overall performance of heat exchangers. Key parameters such as nanoparticle concentration, size, and type are thoroughly evaluated to understand their influence on heat transfer characteristics. Additionally, factors such as stability, flow behavior, and thermal conductivity enhancement are scrutinized to provide a comprehensive understanding of nanofluid behavior in heat exchangers. The review also addresses potential limitations and areas requiring further investigation to optimize the utilization of nanofluids in heat exchanger applications. By synthesizing recent findings, this review aims to contribute to the advancement of knowledge in the field of heat exchanger technology and nanofluid applications. Ultimately, the insights provided in this review offer valuable guidance for researchers and engineers seeking to enhance heat transfer processes through the implementation of nanofluid-based heat exchangers. Nanofluids offer advantages like enhanced thermal conductivity and tailored properties, promising optimized heat exchanger designs, leading to energy efficiency and reduced costs. However, challenges remain, such as nanoparticle dispersion and cost-effectiveness, necessitating further research for refinement. Interdisciplinary collaboration is crucial for advancing nanofluid applications, fostering innovation to meet demands for sustainable heat transfer solutions.