Plate Heat Exchanger Research Articles

Fatigue Assessment of Copper‐Brazed Stainless‐Steel Joints for Plate Heat Exchangers

ABSTRACTCyclic pressures can cause fatigue failure in the brazed joints and plates of the plate heat exchangers (PHEs). This study examines the fatigue behavior of PHEs made from 316L and 304L steels brazed with copper foils employing strain‐controlled fatigue tests to explore if 304L could replace 316L in the existing production line for cost reduction. Fatigue tests were conducted at four different load levels with a stress ratio of zero and a frequency of 5 Hz. Finite Element Analysis was used to assess strain distribution and estimate PHE lifespan based on generated strain versus number of cycles to failure curves. The microstructural analysis revealed that copper diffuses more easily into 316L than 304L, and using 50 μm thick foil causes more defects compared with 100 μm foil. It was shown that 316L joints have a significantly increased fatigue life compared with 304L. Both 316L and 304L met the 15‐year lifetime requirement set by manufacturers.

Research on the thermal comfort of vertical radiant cold plate coupling with a new dual cold source dehumidification air conditioning system

Radiant cooling provides a completely novel air conditioning terminal that could provide better thermal comfort for the resident. However, the radiative system may encounter condensation issues under high-humidity environments. This article studies a radiant air conditioning system with dual-cold-source dehumidification which comprises a plate heat exchanger, a dual-cold fresh air dehumidifier, a capillary radiant cooling wall, and an air-source heat pump. The experimental results demonstrate a positive correlation between the temperature profile of the indoor air and the temperature distribution of the radiant cooling wall. Simulations were conducted to analyze the office’s air temperature and airflow velocity distributions under different supply air volumes and to assess thermal comfort employing computational fluid dynamics (CFD) software. The comfort levels with different air inlet positions are discussed. The simulation results demonstrate that the air conditioning system can maintain a high standard of comfort under an air supply of 350 m³/h.

Investigation of thermodynamics performance of solar dryer equipped with double pass flat, v-corrugated, and low-e coated collectors

In this study, a solar dryer incorporating a flat plate heat exchanger to recover heat from exhaust air was investigated to explore the usability of different types of collectors in the system. Their usability was further evaluated through economic and environmental analyses. Moreover, the thermodynamic performance of the solar dryers was evaluated under two weather conditions in Nepal. Apple drying experiments were conducted for 8 hours from 09:00 to 17:00 from February to April 2023 on solar dryers and with open sun drying (OSD) in Dhulikhel, Nepal. The results showed that the low emissivity (low-e) coated aluminum collector was more efficient in terms of collector efficiency and drying rate than collectors with flat or v-corrugated GI absorbers. The average collector efficiency and drying rate were found to be 89% and 107 g/(h×m2) using the low-e coated aluminum collectors, while the values were 50% and 84 g/(h×m2) for the GI sheet collector. The results indicated a slight improvement in the performance of v-corrugated collectors, with values of 53% and 89 g/(h×m2). The drying rate for OSD was found to be 78 g/(h×m2), which was lower than for the dryers with all collectors used in this study. In terms of economic analysis, the dryer equipped with the low-e coated collector was found to be superior, with a payback time of 1.61 years compared to the dryers with flat or v-corrugated GI collectors. Reducing the thermal losses due to radiation by using the low-e coated absorber was shown to be more important than increasing the absorber area using v-corrugated GI sheets.

Multidisciplinary Optimization of Gyroid Topologies for a Cold Plate Heat Exchanger Design

Abstract The strive to reduce the environmental impact of aviation has led to electrification and increasing demand for powerful on-board power electronic systems. These high-performance electrical components are bound to produce significant amounts of low-quality heat waste that, if not dissipated properly, will lead to malfunctioning and even permanent damage. For this reason, high-performance heat exchangers (HX) represent a key enabler for future advances in aircraft systems electrification and are vital to meet net zero goals and reduce the aviation's carbon footprint. For a given volume of the exchanger, the heat flow rate can be increased by adopting more sophisticated fluid domains. However, excessive geometrical complexity will lead to an increase in pressure losses, often resulting in inhomogeneous temperature distributions. In this paper, a novel optimization procedure is employed to maximize the efficiency of a high-performance heat exchanger, while minimizing overall pressure loss and temperature gradients. The optimization is performed with full three-dimensional high-fidelity computational flow simulations. The geometry of the fluid domain is constituted by triply periodic minimal surfaces (TPMS), with a parametrization based on thickness and aspect ratios, done by using the ntopology suite. To assess the performance gain, the topology-optimized design is compared against the datum case and a conventional serpentine design.

Thermal performance of shell-and-tube polymeric hollow fiber heat exchangers as oil coolers

Motor oil must be appropriately treated in motors, and aluminum plate heat exchangers are used to cool it. An aluminum heat exchanger is an additional part of the oil treatment module, which increases its size and weight. Two compact plastic shell-and-tube heat exchangers were tested alongside with aluminum heat exchanger to evaluate the efficiency of the plastic cooling core inside the oil module. A total of 63 experimental points were tested on three heat exchangers with good thermal balance (discrepancy of about 1,8 %), and the data were used to evaluate the heat transfer coefficients. While plastic unit PA11 showed the heat outputs exceeding the heat output of the aluminum plate unit by about 7 %, the pressure drops were about ten times higher. The unit PEEK showed good performance and pressure drops on the oil side, but the heat transfer was limited by a small heat transfer surface. Analysis of thermal resistances confirmed that the thermal resistance between the wall and the oil is dominant due to the oil's low thermal conductivity and high viscosity. The results showed that optimization of the fiber structures is needed, aiming to increase the oil flow around the fiber structures.

Organic Rankine Cycle System Design by Utilizing The Waste Heat of Internal Combustion Engine Based on Numerical Simulation

Abstract Most of the energy supply for today’s human activities still comes from fossil energy. Energy based on fossil fuels can cause an increase in greenhouse gas (GHG) emissions. Therefore, increasing the efficiency of energy conversion systems based on fossil fuels is necessary to mitigate pollutant emissions. The internal combustion engine (ICE) is one energy conversion machine that still consumes fossil energy to work in the transportation sector. Losses during internal combustion engine operation result in reduced engine thermal efficiency. Exhaust gas heat loss is one of the relatively significant losses. It leads to the waste of heat, which could be utilized and converted into valuable energy in the form of electrical energy that the engine can use, resulting in a considerable amount of primary fuel that could be saved. An organic Rankine cycle (ORC) system is considered in this analysis as a heat recovery unit from the Diesel ICE. The Aspen Plus simulation software was chosen to design the system consisting of an ORC unit integrated with a Diesel ICE unit. The working fluid for ORC used in this analysis is R-141B, R-123, and R-245fa. The simulation results show that the heat the ORC unit receives from the ICE via turbocharger is around 366 °C. Thus, the system has a thermal efficiency of 11.11% when using R-141B as the working fluid, 8.41% if R-123 as the working fluid, and 6.63% when using R-245fa as the working fluid. This study also obtained a condenser design as part of the ORC unit. The condenser can be considered a plate heat exchanger, with 53 plates needed to support the process.

The Heat Transfer Characteristics of Vapor Condensation in a Plate Heat Exchanger

Abstract The model of a single flow channel of a plate heat exchanger (PHE) has been established, and the condensation characteristics of vapor with different saturation temperatures and vapor superheating levels have been investigated. The results show that with a higher vapor saturation temperature, the average surface heat transfer coefficient (HTC) increases. The HTC of saturated steam at a saturation temperature of 348.15 K is about 104.1% higher than that at a saturation temperature of 323.15 K. The influence of vapor superheating is weaker compared to that of the saturation temperature. With the increase of vapor superheat, the surface average HTC first increased and then decreased. The HTC of superheated vapor with a vapor superheating of 10 °C is about 0.72% higher than that of saturated vapor. In industrial applications, it is appropriate to control the vapor inlet superheating to be between 5-10°C.

Utilizing novel industrialized heat exchanger plate in air-based photovoltaic/thermal collectors to enhance thermal and electrical efficiency

This study aims to design a highly efficient and applicable air-based photovoltaic-thermal (PVT) collector that maximizes both electrical and thermal energy efficiencies. An innovative industrialization-ready configuration of the air-based PVT system is proposed, utilizing an industrialized heat exchanger (GRIPMetal or GM) as the absorber plate for the PVT air channel. The heat exchanger consists of spikes and cavities to enhance the heat transfer coefficient in the air channel. The proposed heat exchanger plate minimally affects the dimensions and weight of the PVT collector. A numerical model, validated against experimental results, is used to ensure the accuracy of the simulation. The study is followed by a parametric study that investigates the geometric effects of the heat exchanger and air channel, as well as the airflow rate, on the overall performance of the PVT system. It is observed that the utilization of GM plates significantly reduces the average PV panel temperature (with a maximum of 28 ℃ reduction) and enhances the convective heat transfer coefficient in the air channel, the electrical and thermal efficiencies by approximately 164%, 16.1%, and 50%, respectively, when compared to a flat plate PVT collector. The results demonstrate that the proposed PVT collector effectively compensates for the pressure drops and excess fan power consumption at low Reynolds numbers due to the GM heat exchanger, resulting in higher overall system efficiency. The optimal configuration for the proposed PVT system is achieved by employing a low airflow rate, a narrow air channel, and GM spikes of the largest size available.

Thermal-hydraulic performance of R1234yf in brazed plate heat exchanger at low saturation temperature and mass flux conditions: Experimental investigation

This study investigated the heat transfer coefficient (hr) and two-phase frictional pressure drop during the evaporation of R1234yf within an offset strip fin (OSF)-structured brazed plate heat exchanger (BPHE). The work is conducted at a saturation temperature (Ts) of −3 to 3 °C, with mass flux (G) ranging from 25 to 45 kg m−2 s−1 and heat flux (q) between 15 and 23 kW m−2 across a vapor quality (x) range of 0.1–0.8. Understanding these behaviors is critical for optimizing BPHEs in low-temperature applications, such as heat pumps, where energy efficiency is essential. The novelty of this work lies in its exploration of operating conditions that are less studied in the literature, particularly the impact of low Ts, low G, and high q on hr and two-phase frictional pressure drop in an OSF-BPHE with R1234yf. Unlike prior studies focusing on convection-dominated boiling, our findings reveal a coexistence of nucleate and convective boiling mechanisms, especially at different vapor qualities. The hr is significantly influenced by q at x < 0.6, G at x > 0.6, and Ts across all x. In contrast, evidence of dryout at high x highlights the importance of these parameters in managing heat transfer efficiency. The results indicate a strong correlation between the two-phase frictional pressure drop and G, with a marked increase in it at higher G. Besides, this study reveals flow characteristics commonly linked with both macrochannel and minichannel flows, enhancing novelty by bridging the gap between these two regimes. These findings challenge existing literature correlations that predominantly emphasize convection-dominated behavior and contribute to a better understanding of the dual boiling mechanisms in BPHEs.

Numerical and experimental investigation of additive manufactured heat exchanger using triply periodic minimal surfaces (TPMS)

With the increasing demand for high-efficiency compact heat exchangers in automobiles and spacecraft, lighter and more efficient metamaterials hold promise as advanced materials for cooling applications but remain beyond reach. Triply Periodic Minimal Surface (TPMS) structures, characterized by their smooth surfaces and significantly huge volumetric surface area, represent ideal internal structures for heat exchangers, and the development of additive manufacturing has made their design and production possible. This study focuses on designing heat exchangers based on seven TPMS structures (Fischer-Koch S, Gyroid, SplitP, Diamond, I-WP, F-RD, Primitive) and prints the finished heat exchangers using AlSi10Mg material based on numerical investigation results. Comprehensive evaluation metrics are used to rank the results. The findings reveal that the internal interleaved channels have varying effects on different structures, with Fischer-Koch S exhibiting the highest heat transfer capability of up to 269 W/K. Gyroid and I-WP demonstrate the best fluidity, with resistance only 23.44 % of Primitive’s. Gyroid has the best overall evaluation metrics, with a 54 % efficiency improvement over traditional plate heat exchangers. Additionally, this study proposes the use of the Voronoi algorithm to handle the channels of TPMS and identifies the asymmetric characteristics of heat exchangers on both sides, and it is believed that there is still greater optimization potential for the performance of TPMS heat exchangers

Performance analysis of Plate type Steam Condenser Using Nano-fluid

Abstract This paper investigates the application of nanofluid coolant, specifically a mixture of water and aluminium dioxide (Al2O3) nanoparticles, to augment heat transfer efficiency within flat plate heat exchanger. Beginning with an introduction highlighting the pivotal role of heat exchangers in industrial processes, the study emphasizes the imperative for enhanced efficiency and reduced energy consumption. The system description delineates the components and functionality of flat plate heat exchanger, elucidating operational and experimental conditions including initial temperatures and subsequent temperature transitions during cooling. Key parameters such as effectiveness and overall heat transfer coefficient are identified, with an exploration of their variation when comparing water alone to nanofluid coolant. Comparative data showcases experimentally obtained effectiveness and heat transfer coefficient values for both coolant types, revealing a substantial enhancement in efficiency with nanofluid coolant. Like effectiveness for water was 18% while that for nanofluid was 35%. The future potential and broader applications of nanofluid coolant in heat transfer technologies, advocating for continued research to unlock further advancements and efficiencies in industrial processes. By this technology we can reduce water losses as well as reduce power consumption in plants.

Design of a Steady-State Adjustment Method and Sensitivity Analysis for an ORC System with Plate Heat Exchangers

Design of a Steady-State Adjustment Method and Sensitivity Analysis for an ORC System with Plate Heat Exchangers

A simplified LMTD approach to assess the effectiveness of a chevron-type plate heat exchanger

A simplified LMTD approach to assess the effectiveness of a chevron-type plate heat exchanger

Structural analysis and sealing capacity of gasketed plate heat exchangers with HNBR and EPDM rubbers

Structural analysis and sealing capacity of gasketed plate heat exchangers with HNBR and EPDM rubbers

Prediction of thermo-hydraulic properties of flow in an innovative plate heat exchanger using machine learning algorithms

Reducing fuel consumption and toxic gas emissions is a major concern in modern energy research. This paper investigates the performance and heat transfer enhancement of an innovative plate heat exchanger (IPHE) using machine learning techniques. By optimizing the geometric parameters of the plate, we predict thermohydraulic characteristics—represented by the Nusselt number (Nu), coefficient of friction (f), and performance (P) within the Reynolds number range of 500–5000 based on numerical modeling data. This study addresses the need for improved efficiency in plate heat exchangers (PHEs) amid rising energy demands and environmental concerns. Traditional methods like numerical simulations or costly experiments have limitations, prompting interest in artificial intelligence (AI) and machine learning (ML) for thermal analysis and property prediction in PHEs. Various ML models, including Decision Trees, XGBoost, Gradient Boosting, and ensemble methods, are evaluated in predicting f, Nu, and overall performance (P). Our comprehensive experimentation and analysis identify top-performing models with robust predictive capabilities. For f, the highest R2 score was 0.98, indicating excellent prediction accuracy, with mean squared error (MSE) values consistently below 0.0016. Similarly, for Nu and P, top models achieved R2 scores of 0.979 and 0.9628, respectively, with MSE values below 0.0347 and 0.05. These results highlight the effectiveness of machine learning techniques in accurately predicting thermohydraulic properties and optimizing PHE performance.

Flow and heat transfer characteristics and comprehensive evaluation of asymmetric plate heat exchangers for centralized heat supply

The structure of flow channel on both sides of the conventional plate heat exchanger(CPHE) is symmetrical. CPHEs are struggle to perform efficiently when subjected to asymmetric working conditions in district heating system. In order to improve the performance of plate heat exchangers under asymmetric conditions, asymmetric plate heat exchangers(APHEs) was designed. In this paper, APHEs were parameterized by asymmetric factor a. An evaluation index η for APHE is introduced to quantitatively analyze APHE’s suitability in district heating system. Numerical simulations were performed to investigate the heat transfer characteristics and resistance characteristics of the APHEs with 11 asymmetric factors a. Through using η, APHEs with the best comprehensive performance were found, when the flow ratio is 1.50, 1.75, 2.00, 2.25, 2.50 and 2.75. In flow ratio, APHEs provide the comprehensive performances with an improvements of 28 %, 39 %, 54 %, 65 %, 72 % and 83 % compared with CPHEs. Correlations equation for the average Nu and f on both hot and cold sides of the APHEs were established. There exists a correlation between Nu and f for the APHEs with respect to asymmetry factor a and flow ratio.

Study of ultrasonic parameters for quality monitoring of plate heat exchanger

Abstract Heat exchangers are crucial heat transfer devices widely used in energy industries such as power generation, oil production, and engine cooling. The plate heat exchanger is one of the most economical and efficient types of exchangers. It transfers heat using metal plates and has a high heat transfer efficiency because the fluid is exposed to a higher plate surface area. However, due to the presence of dissolved or suspended particles in the heat-exchanging fluids, a layer of deposit (fouling layer) is formed on the heat exchanger plates. It results in reduced efficiency of the device. Thus, a common cleaning method, such as chemical-based or manual methods, is employed. However, it always poses a risk of over-cleaning or removal of the protective oxide layer. Thus, an efficient mechanism to monitor the onset of the fouling layer would greatly help to achieve increased efficiency and cost reduction in the cleaning of the plates. Recent advances show ultrasound as one of the promising non-destructive inspection techniques to monitor the growth of the fouling layer. However, the variation in heat-exchanging fluid temperature affects the investigated acoustical parameter measurement. Thus, this research aims to study the linear and nonlinear ultrasonic parameters incorporating temperature-dependent effects from the fluid to provide an accurate real-time monitoring tool. The nonlinear acoustics analysis is experimentally employed in the research using the Second harmonic generation method (SHGM). The proposed research will help design ultrasound-assisted plate heat exchangers for maximum heat transfer efficiency.

Performance assessment of deep borehole heat exchanger heating system under different heating modes

Abstract With the transition towards renewable energy sources, particularly as we move away from fossil fuels, there has been a constant evolution of deep borehole heat exchanger (DBHE) coupled heat pump heating technology. On the basis of the heat-exchanging properties of circulating fluid in the DBHE heating system, this paper clarifies the setup forms of this system, and elucidates the influence of heat extraction performance. After analysis and research, it can be concluded that the direct supply mode shows a more prominent decline in water temperature compared to the coupled heat pump and coupled plate heat exchanger modes. The imported and exported water temperatures when heating ends were recorded as 9.98°C and 16°C, respectively. The imported and exported water temperatures for both the direct supply and the coupled plate heat exchanger modes tend to be similar at 19.6°C and 25.5°C at a temperature of 7°C. Heat pump not only enhances the heat exchange features of ground source heat pump (GSHP) heating system, but also defines the configuration of heat extraction performance of DBHE. The system power consumption in the coupled plate heat exchanger mode is lower than that in the heat pump mode which is conducive to stable operation. Therefore, the best design form of the DBHE Heating System is the heat pump coupled plate exchange mode.

Flow boiling in dimpled plate heat exchangers with different geometric parameters: Analysis of asymmetric channels

The evaporators of heat pumps extract heat from the environment. To improve the heat pump performance in cold environments, evaporators must operate with small temperature drops of the heat source, which requires large flow rates of the secondary fluid. This paper discusses dimpled plate heat exchangers (DPHEs) with flexible flow section areas. The flow boiling of R410A is measured in six channels. The flow section area ratios of neighboring channels are 0.86–2.83. To analyze outlet superheat, the two-phase and dryout zones are distinguished using infrared measurement. The dryout zone is a function of the superheat and mass flux, which is quantified. The heat transfer coefficients (HTCs) increase with increasing mass fluxes and heat fluxes. Compared with experimental results from a large scope, the present data fall into the combined regimes of convective boiling and nucleate boiling. Smaller hydraulic diameters slightly enhance the heat transfer. The experimental HTCs are accurately predicted by a correlation of chevron plate heat exchangers (CPHEs). The performances of the DPHEs and CPHE are compared for small temperature drops in cold environments. The DPHEs have superior performance by mitigating the unbalance of mass fluxes. The typical overall heat transfer coefficient is improved by 62%. The improvement depends on the flow section area ratios.

Assessment of transient thermal stresses in gasketed plate heat exchangers

Thermal and mechanical stresses in stainless steel 316 L plates of gasketed plate heat exchangers (GPHEs) have been assessed with the aid of experiments. Stresses were indirectly determined with the aid of extensometers in critical plate areas. To the best of our knowledge, no experimental analysis of transient thermal loads on GPHE plates has been reported before. Experiments occurred with sudden and gradual heating processes with the aid of strain gauges. The former process implies that hot fluid enters the GPHE branch with the final target temperature, while the latter indicates that the hot fluid is progressively heated to the target temperature. Furthermore, combined mechanical and thermal stresses resulting from in-phase and out-of-phase loads are assessed in single and double operating conditions. Experiments were carried out with two plate thicknesses (0.5 and 0.7 mm). Stresses as obtained from experiments were compared to those provided by models containing simplified geometries and boundary conditions. Mechanical stresses promoted by the pressure difference between GPHE branches mostly affected the distribution area in single configuration. Thermal stresses at the porthole were higher than the ones found at the distribution zones, particularly for thicker plates. Besides, thermal stresses increased in double operation. Sudden heating processes with the system at rest promoted thermal peaking stress in a timescale of seconds, while the timescale to reach peak values by gradually heating the hot fluid is in the order of minutes. The most critical condition would be achieved at the porthole with in-phase loads and in double operation for the given settings.