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• An experimental ACS was assessed operating with the NH 3 -H 2 O-LiBr mixture. • The results of the proposed mixture were compared with the binary mixture NH 3 -H 2 O. • The compact prototype was built up utilizing plate heat exchangers. • The system's response was analyzed in a wide range of operating conditions. • COP of 0.4, cooling load of 2.7 kW and cooling temperature of -20 °C were achieved. Absorption cooling systems present an appealing alternative to conventional compression systems as they can leverage low-grade heat sources to generate a cooling effect. The choice of the working fluid in the absorption system plays a crucial role in its performance and applications, making it a critical factor in the system's design and operation. While specific hypotheses in the literature propose advantages of using ternary mixtures over typical binary working fluids, existing experimental studies lack conclusive evidence. Therefore, further research on this topic is imperative. This study experimentally assesses the performance of a single-effect absorption cooling system using the ternary NH 3 -H 2 O-LiBr mixture. The results are then compared to those of the binary NH 3 -H 2 O mixture. The assessment and comparison cover a wide range of operating conditions and similar concentration values. The results indicate that, from an operational standpoint, the ternary mixture offers significant advantages regarding system pressures and operational stability. However, from a performance perspective, at least within the tested mixture concentrations, the ternary mixture generally appears less attractive than the binary mixture. Nevertheless, it is worth noting that when driven by heat sources at higher temperatures, the ternary mixture could exhibit relevant performance characteristics. [ABSTRACT FROM AUTHOR]

In industrial robot welding heat exchanger plate route planning, there are drawbacks to using the traditional ant colony algorithm (ACA), including poor search efficiency and a propensity to trend toward the local optimum. To address the above issues, first of all, the article introduces the improved pheromone volatilization factor, which is adjustable based on iteration times in the ACA. Secondly, it combines the new perturbation strategy and the cross‐mutation operation, proposes an improved genetic algorithm, and fuses it into the ACA, which increases the diversity of the ACA's path searching and improves the ability of the local and global search. Finally, the improved ACA mechanism is verified by experiments and compared with six existing path planning algorithms (including three ACA variant algorithms and three mainstream algorithms). The experimental results show that the IACAG algorithm has excellent performance in welding heat exchanger path planning and can achieve lower calculation time and iteration times under the conditions of optimal solution and zero deviation, showing comprehensive advantages in solution quality, stability, and efficiency. [ABSTRACT FROM AUTHOR]

Pillow plate heat exchangers show promising performance in extending the operating range of thermosiphon reboilers. Here, the evaporation of binary mixtures during natural circulation evaporation in a pillow plate apparatus was investigated. The experimental results show that the thermal performance is dominated by mixture effects and a component system‐dependent minimum is found. The model approach according to Bennett and Chen has proven to reliably estimate the product‐side heat transfer coefficient for pure substances and mixtures with a low boiling point distance. For wide‐boiling mixtures and low pressures the approach must be adjusted. [ABSTRACT FROM AUTHOR]

• Heat transfer coefficient of three component zeotropic mixture was measured. • A specially designed test section was used for local heat transfer measurement. • An asymmetrical distribution of heat transfer coefficient was observed. • A prediction correlation utilizing the mixture resistance was developed. Plate heat exchangers are gaining popularity as condensers for their compact design and high efficiency. However, the uneven fluid distribution in channels poses a challenge to effective heat transfer. Existing literature lacks experimental analysis of local heat transfer coefficients for pure and zeotropic mixture refrigerants in plate heat exchangers. This study experimentally analyzed the local heat transfer of the three-component zeotropic mixture R455A at various conditions (mass flux 20, 30, and 50 kg m−2 s−1 and saturation temperatures 30 and 35 °C). Results show that the heat transfer coefficient increases with flow rates and decreases with saturation temperature. However, results indicated lower heat transfer coefficients compared to pure refrigerants due to mixture effects. In addition, the local distribution of the heat transfer coefficient revealed that the heat transfer coefficient is highest at the center compared to the edges of the channel due uneven distribution of refrigerants within the channel. This HTC pattern confirms an asymmetrical flow within the plate. A new correlation is being developed to predict the heat transfer coefficient of the ternary mixture, showing improved accuracy than previously proposed correlations. [ABSTRACT FROM AUTHOR]

Because of its low concentration and low energy in an organic Rankine cycle (ORC) system, more than 50% of low-grade thermal energy with a temperature below 300 °C is not taken seriously. The relationship between changeable working condition parameters and operating parameters is typically not taken into account in a model while studying ORC systems. It is insufficient to analyze the system performance changes solely on changes in the performance parameters of the heat exchangers. Furthermore, a model perspective of the system control solution is absent from the steady-state control of the system when the heat source varies. In this paper, we created a system model for the application scenario of a 100–200 kW ORC system with brazed plate heat exchangers in order to address the aforementioned issues using MATLAB R2016b. Additionally, a sensitivity analysis of the system was conducted based on heat exchangers of performance variations. In addition, a modeling computation and adjustment scheme were put forth to guarantee that the system could continue to produce steady power production even when the temperature of the heat source fluctuated. Preliminary results showed that the system's internal parameters included its evaporation pressure and condensation temperature. An increase in evaporation pressure will reduce the mass flow rate and heat flux of an evaporator, thus reducing the heat transfer coefficient. The two-phase region of the evaporator accounted for the highest proportion, of 70.22%, and continued to increase to 75.83%, followed by the supercooling region, and gradually decreasing. The utilization rate of the evaporator decreased from 74.85% to 38.32%. The system output power increased first and then decreased, with a maximum value of 153.11 kW. The system efficiency increased from 5.74% to 11.04%. The increase in condensation temperature increased the proportion of the two-phase region and the superheating region, and the mass flow rate did not change much. The increase in heat flux increased the heat transfer coefficient from 1721.31 W/(m2·K) to 2374.77 W/(m2·K), and the utilization rate of the evaporator decreased from 70.56% to 51.91%. The aforementioned change rules were used in the building of the steady-state regulation model to balance out the changes in the generating power as the heat source temperature increased. The model output was cross-checked and validated against pertinent experimental test literature data. The results of this research can serve as a valid and useful guide for ORC system design and practical applications. [ABSTRACT FROM AUTHOR]

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Plate heat exchangers have served various industrial applications for decades, with brazed plate heat exchangers (BPHE) emerging as preferred choices due to their favorable operating conditions. While extensive research has been conducted on flow patterns in gasketed plate heat exchangers, similar studies for BPHE have been lacking, given their analogous geometry. However, recent years have witnessed a surge in research focusing on single and multi-phase flow dynamics. Advancements in computational fluid dynamics (CFD) have furthered our understanding by providing insights into flow and heat transfer patterns, while also reducing the need for costly experimental tests of different geometries. This has facilitated the adoption of parametrization, bolstered by the feasibility and accuracy of numerical models. Nevertheless, substantial research remains to be undertaken to develop comprehensive models capable of integrating multiple geometric and flow parameters. This article examines existing research on BPHE and outlines potential areas for future exploration to address current research gaps. [ABSTRACT FROM AUTHOR]

This paper provides the groundwork for the most efficient design of freshwater generating systems that take advantage of waste heat from the main engines. In the desalination process, freshwater generators, whether in the form of shell and tube-type or plate-type, are employed. Merchant vessels primarily utilize submerged shell and tube-type evaporators to generate fresh water. The foundation for comprehending separation processes, energetics, and economics lies in the quantitative interpretation of the second law of thermodynamics, with a specific focus on exergy and its dissipation. This research suggests employing exergy analysis to utilize waste heat as a valuable resource in a single-effect desalination process to meet freshwater needs, considering practical aspects. The study involves analyzing a freshwater generator of the Shell and tube type situated at the Tolani Maritime Institute in Pune, India. Thermal properties are calculated and visually represented through a flow diagram using a C++ program. The assessment of exergy unveils the extent and distribution of unattainable work within a freshwater generator employing a shell and tube design, particularly concentrated in its key components: the evaporator, condenser, and brine section. These findings are contrasted with those from a Plate Type Heat Exchanger (PTHE) freshwater generator. The rate of exergy destruction in Plate Type Heat Exchanger freshwater generators is 29.33%, whereas in shell and tube-type freshwater generators, it is higher at 44.88%. [ABSTRACT FROM AUTHOR]

An energy and exergy analysis of an experimental air-conditioning absorption system operating with the ammonia-lithium nitrate mixture has been performed. The system was operated under controlled and steady-state conditions. The main operating parameters, such as flow ratio, coefficient of performance, exergy coefficient of performance, and exergy destruction in each one of the main components, were determined at different heat sources and condensing temperatures. The coefficients of performance varied between 0.5 and 0.65, while the exergy coefficients of performance varied between 0.1 and 0.2. Clear trends were found for the coefficient of performance and flow ratio as a function of the generator and condenser temperatures; however, no trends were found in the exergy coefficients of performance due to the high variability of the ambient temperature. The highest values of the exergy destruction occurred in the generator, followed by the condenser and the evaporator, while the lowest values were obtained in the absorber and the economizer. [ABSTRACT FROM AUTHOR]

The objective of this paper is to provide the reliable calculation procedure for determining heat and mass flow rates for plate finned tube heat exchangers in dehumidification regimes that can be used easily in engineering practice. For this purpose, the experiments are conducted on two heat exchangers, and datasets for six more heat exchangers are used from literature. Comprehensive database is established with total of 637 sets of data, and it gathers 365 new measurement sets and 272 sets from open literature. The new calculation procedure predicts heat transfer rate and condensate flow rate where new methodology approach (based on the porous velocity, the ratio of characteristic surfaces and hydraulic diameter) is used. Predicted results show 5–10 % deviation for heat duty and up to 20 % for mass flow rate from experimental results, which is of importance to industrial practice. [ABSTRACT FROM AUTHOR]

Traditional air conditioning systems use lot of energy; thus, dew point evaporative air-cooling systems could be a good alternative. Many experts studied the impact of constructional and operating characteristics on Maisotsenko cycle (M-cycle) to improve its performance. Cooler performance is influenced by the heat exchanger. Heat exchangers were constructed using flat and corrugated plates. The present study proposes the use of geometrically modified trapezoidal corrugated plates for counter flow heat exchanger, which consists of alternate air and water flow passageways. The numerical model is developed to predict the performance under variety of inlet air conditions and channel dimensions. In the standard range of incoming air properties such as relative humidity, the performance parameters assist in making cooler recommendations. Comparison and validation of simulation results are done with published experimental data for corrugated and trapezoidal corrugated plate heat exchangers. For trapezoidal corrugated plates, simulation findings revealed 10% increase in wet bulb efficiency and 7% increase in dew point efficiency over corrugated plates. The efficiency of wet bulb and dew point decreases as channel gap widens. For trapezoidal corrugated plates, the larger channel spacing minimises pressure drop. [ABSTRACT FROM AUTHOR]

Plate heat exchangers provide a compact and efficient alternative to bulky and spacious shell-and-tube heat exchangers. With numerous plates and flow passages, plate heat exchangers increase the flow transit time and enhance hot-fluid-to-cold fluid contact promoting higher heat transfer rates than conventional designs. Plate condensers and evaporators offer cost-effective, compact, and highly efficient alternatives to traditional surface condensers and evaporators. This article reports the empirical modeling and meta-analysis of over two-thousand heat transfer data compiled from thirty-five experimental investigations in the past three decades. The predictive correlations validated against an extensive database should be helpful to the industry and academia. Meta-analysis of the phase-change heat transfer data was statistically insignificant, and the current practice of deploying plate heat exchangers should be encouraged. [ABSTRACT FROM AUTHOR]

Sol-gel derived antifouling coatings for use in crude oil heat exchangers have been successfully utilized for years. The combination of a very thin and heat conductive coating with low surface energy and low surface roughness in an inert glass ceramic matrix has proven very effective in preventing fouling accumulation and maintaining sustained production. A challenge using very thin and transparent sol-gel coatings is reassuring that the items are actually coated and are correctly applied. For plate heat exchangers, that may only be single side coated, it is important that the unit is assembled correctly, so that the coated side of the heat exchanger plates face the crude oil. Also, for inspection purposes and for estimation of residual lifetime, it is important to be able to establish the quality of the coating efficiently and quickly – also inside individual tubes of a shell and tube heat exchanger. Here we present ongoing coating development of Thermo Coat 200 (TC200), an antifouling coating stable up to 300 °C/572 °F, which is provided with inert and heat stable pigments that allow quick inspection of coating integrity, both before and after operation. Together with procedures for testing coating repellency and substrate adhesion, the pigmented TC200 coating may facilitate the industrial transition to antifouling coatings. [ABSTRACT FROM AUTHOR]

Fouling of heat exchangers in the chemical industry, oil & gas industry, district heating, power plants, among others, results in a loss of performance which leads to production stops for cleaning and therefore increased operation costs. One approach to mitigate fouling is to alter the properties of the metal surface. A coating to be successful in any plate heat exchanger (PHE) application needs to have a good adhesion to the metal but also keep the heat transfer through the metal plates as unaltered as possible. This requires a thin coating with a relatively good thermal conductivity. The plates in a PHE are subjected to plate-to-plate contact point wear when in operation which also puts an extra requirement for the coating. To be suitable, the coating needs to have a good mechanical stability to resist this plate-to-plate wear. Alfa Laval has a long experience in coating plates for diverse applications and in this paper two case studies will be presented. One in the paper industry and the other in the biofuel industry. A new type of multilayer Teflon™ coating from Chemours was used, specifically designed to show excellent fouling release properties along with limited thicknesses (30–50 microns). [ABSTRACT FROM AUTHOR]

As building becomes more leak-tight, air refreshment to improve indoor air quality is needed for healthy living standards. In the quest to ensure comfortable indoor climatic conditions, energy recovery ventilators (ERV) are used to provide air refreshment and thermal comfort. In this study, a fixed plate air-to-air ERV was analysed to determine its effectivity in terms of energy recovery during air refreshment. A customized test bench was built and used to acquire the instantaneous surface temperatures of the heat exchanger plates contained in the ERV during air refreshment. Also, a numerical model of the ERV was developed and validated by comparing its output from simulation with experiment results under the same conditions. The model consisted of a single heat exchanger plate and the air across the plate surface. To capture the effect of heat transfer between the air and the heat exchanger plate in 3D, the model was discretized into numerous cells. From the experiment and simulation results, the air-to-air ERVs were more effective in recovering thermal energy at low flow velocity than at high flow velocity. At lower flow velocity, it will take a longer time duration before any significant impact is made on the thermal conditions of the building, comparatively. The prediction of the model was within acceptable margins and could be used to provide insight on the ERVs performance improvement. [ABSTRACT FROM AUTHOR]

Computational fluid dynamics (CFD) simulations were employed to model a novel double sine wave corrugated heat exchanger surface. The turbulent flow within the heat exchanger channels was simulated using the k - ω SST model for the corrugated cases. In contrast, a laminar model was applied to the flat plate heat exchanger without corrugations. The simulation results demonstrate that 3D-printed polymer heat exchangers are effective for heat transfer, with the double-sine wave corrugated surface outperforming the single-sine wave corrugated surface. Specifically, the double sine wave configuration achieved a 20% higher Nusselt number and a 15% lower friction factor than the single sine wave, indicating superior thermal-hydraulic performance. Optimal performance was observed with low amplitude and frequency of the sine waves, suggesting that small protrusions and wider-spaced corrugations enhance heat transfer without significantly increasing pressure drop. These findings have significant implications for the design of efficient and cost-effective heat exchangers, particularly in applications where both thermal performance and energy efficiency are critical. Further experiments with full-scale heat exchangers are necessary to validate these results and explore practical applications. [ABSTRACT FROM AUTHOR]

The current research analyses the influence of corrugation pitch on channel frictional factor (CFF), channel pressure drops, and total pressure drop in a single pass chevron plate heat exchanger, across Reynolds numbers ranging from 2004 to 5421. Single corrugated chevrons with a chevron angle of 60° are utilized. Corrugation pitch significantly influences fluid flow distribution in the channels, consequently affecting flow maldistribution, and pressure drop in PHEs. Additionally, the enhancement in CFF for decreasing the aspect ratio at the same flow rate is examined. The study reveals a decrease in channel pressure drops in the range of 79.79% to 82.25%, when increasing the corrugation pitch from 12 mm to 30 mm and decreasing the aspect ratio from 56.4 to 31.33. The current analytical results have been confirmed by comparing them with the experimental findings reported in previous studies. Although higher pressure drops can enhance heat transfer by increasing turbulence and improving flow distribution, however they demand more energy for pumping, that can ultimately impact overall system's efficiency. Hence, finding an optimal balance is crucial for achieving efficient heat exchanger operation. [ABSTRACT FROM AUTHOR]

Gravity-assisted separation heat pipes (GSHPs) are extensively utilized in telecommunications base stations and data centers. To ensure year-round cooling, integrating GSHPs directly with a vapor compression refrigeration system is a viable solution. It is unavoidable that the refrigeration system's lubricant will infiltrate the heat pipe loop, thereby affecting its thermal performance. This paper examines the performance of a GSHP, which features a water-cooled plate heat exchanger as the condenser and a finned-tube heat exchanger as the evaporator, when the working fluid (R134a) is contaminated with a lubricant (POE, Emkarate RL-46H). The findings are compared with those from a system free of lubricant. The experimental outcomes indicate that the presence of lubricant degrades the heat transfer efficiency, particularly when the filling ratio is adequate and no significant superheat is observed at the evaporator's outlet. This results in a 3.86% increase in heat transfer resistance. When the charge of the working fluid is suboptimal, the average heat transfer resistance remains relatively constant at a 3% lubricant concentration yet increases to approximately 5.27% at a 4–6% lubricant concentration, and further to 12.32% at a 9% lubricant concentration. Concurrently, as the lubricant concentration fluctuates between 3% and 9%, the oil circulation ratio (OCR) varies from 0.02% to 0.11%. [ABSTRACT FROM AUTHOR]

Based on the differential idea, this article establishes two segmented algorithms which are the linear equations method and iterative method for solving the one-dimensional digital twin of the temperature field and pressure field of plate heat exchanger (PHE). The segmented algorithms are to consider the change of the physical properties of the fluid along the flow direction, which makes the solution of the temperature field and pressure field more accurate than that without segmentation. It can still get other important parameters besides temperature and is easy to converge with a few iterative steps. When the boundary conditions are known, it can accurately solve the heat transfer, wall temperature, convective heat transfer coefficient, temperature field and pressure field of fluid. Under six groups of test conditions, the heat exchange, temperature and pressure calculated by the two algorithms are compared with the commercial software Flownex, when the number of segments is 100, the average maximum error of each segment is not more than −0.39%, −0.97%, and 0.18%, respectively. To balance accuracy and calculation speed, this article also explores the impact of the number of segments on accuracy. It is found that when the number of segments increases to 10, the impact on the calculation accuracy can be ignored. Compared with Flownex, these two algorithms have smaller errors, and the solution speed of solving linear equations method is faster than that of iteration. It provides application value for emerging digital twin technology, data center chilled water system and other projects and industries that need to accurately control the outlet temperature and wall temperature of PHE. [ABSTRACT FROM AUTHOR]

In this study, a numerical investigation of fluid flow and heat transfer of Al2O3‐water nanofluids in a pillow plate heat exchanger with a two‐phase model is investigated. The flow regime studied in this study is in the laminar flow regime such that the Reynolds numbers are 250, 500, 750, and 1000 and the volume fraction of the nanoparticles remained so that the fluid stayed in Newtonian. The volume fraction of nanoparticles is ϕ=$\phi = $ 0, 1, 2, and 3 %. In this study, the effect of the shape of the welding points used in the pillow plate has also been investigated in such a way that three modes of circular welding point, large‐diameter elliptic welding point along with the flow and large‐diameter elliptic welding point perpendicular to the stream have been investigated. Numerical simulation results show that using nanofluid and increasing Reynolds number improves heat transfer, as well as circular welding point, shows the best heat transfer rate. The shape of the welding points has a direct relationship with the pressure drop and heat transfer, as well as the wake created behind the welding points, which have the highest wake and pressure drop respectively for the elliptic welding points perpendicular to the flow, circular and elliptical parallel to the flow. On the other hand, the addition of nanoparticles increases the friction factor and, on the contrary, increases the Reynolds number, which reduces the friction factor. Finally, the highest Reynolds number, the highest volume fraction of nanoparticles, and the circular welding point state show the highest PEC. [ABSTRACT FROM AUTHOR]

The absorption heat exchanger with a large temperature difference has a higher heat transfer superiority than the other heat exchangers (including plate heat exchanger), which is more suitable for long-distance heating. To improve its system performance, parameter collaborative optimization (including building accurate predictive models) has become an effective method because it does not require too much investment. In this study, a heat exchange station was chosen as a case study, and a model of a long short-term memory (LSTM) neural network was used to predict the temperatures of primary return water and secondary return water. Accordingly, the reliability of the fitting result based on the model was confirmed through a contrastive analysis with the prediction results of a support vector machine (SVM) model, a random forest (RF) model, and an extreme gradient boosting (XGBoost) model. In addition, the algorithm of particle swarm optimization was used to optimize the flow rate of primary supply water. The results showed that the temperature of primary-side return water decreased from 29.6 °C to 28.2 °C, the temperature of secondary-side return water decreased from 39.8 °C to 38.6 °C, and the flow rate of primary-side supply water decreased from 39 t/h to 35.2 t/h after the optimization of the flow rate of primary supply water. The sensibility assessment emerged that the secondary-side flow rate to the secondary-side supply water temperature was about 7 times more sensitive than the primary-side supply water temperature, and concretely, the lower the temperature, the higher the sensibility. In summary, the accuracy of the proposed prediction model was validated and the optimization direction was pointed out, which can be used to provide guidance for designing and planning absorption heat exchange stations with large temperature differences. [ABSTRACT FROM AUTHOR]

This research proposes advanced model-based control strategies for a countercurrent flow plate heat exchanger in a virtual environment. A virtual environment with visual and auditory effects is designed, which requires a mathematical model describing the real dynamics of the process; this allows parallel fluid movement in different directions with hot and cold temperatures at the outlet, incorporating control monitoring interfaces as communication links between the virtual heat exchanger and control applications. A multivariable and non-linear process like the plate and countercurrent flow heat exchanger requires analysis in the controller design; therefore, this work proposes and compares two control strategies to identify the best-performing one. The first controller is based on the inverse model of the plant, with linear algebra techniques and numerical methods; the second controller is a model predictive control (MPC), which presents optimal control actions that minimize the steady-state errors and aggressive variations in the actuators, respecting the temperature constraints and the operating limits, incorporating a predictive model of the plant. The controllers are tested for different setpoint changes and disturbances, determining that they are not overshot and that the MPC controller has the shortest settling time and lowest steady-state error. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the heat flow in a plate heat exchanger located at a building heat exchange station. The plate heat exchanger is the main source of heat for the building system based on microsubstations in the building apartments. The co-operation of the heat exchange station with the substations in the apartments is also described. Such microstations are intended for both domestic hot water preparation and apartment heating. The method of calculating the product of the heat transfer coefficient k and the heat exchange surface area A is presented. In order to verify the correctness of the measured values of the temperatures of hot and cold water at the heat exchange station inlet and outlet, they were compared to the values calculated using the ε-NTU method. Good agreement was found between the results of the calculations and the measurements. Recommendations were made for the temperature of return water to the heating station. The cost of operating the district heating network could be reduced by increasing the surface area of central heating radiators in apartments, so that the temperature of return water to the heating station could be lowered. [ABSTRACT FROM AUTHOR]

In modern industrial plants, compressed air is the most commonly used energy source; however, it is a source of condensation, which is not desirable for pneumatic equipment. This article describes a model of compressed air drying based on the principle of a refrigeration dryer. However, instead of gas refrigerants, the method proposed is to use cooled compressed air as a cooling medium with a temperature below 273 K. The main objective is to study the possibility of replacing harmful refrigerant gases with a neutral type of coolant. To carry out this research, a test bench containing a plate heat exchanger and a throttling device was designed and manufactured. This study has yielded the following scientific results. Firstly, the Joule–Thompson effect was used during the experiments, which facilitated a reduction in the temperature of the compressed air to 255 K. Secondly, using the expanded air and a plate heat exchanger, the temperature of the main compressed air stream was reduced to 280 K, which is very close to the temperature provided by standard-refrigeration-type compressed air dryers. This suggests that it is possible to use compressed air energy to cool the main stream of warm compressed air after the compressor. In general, the temperature range ensures the compressed air quality at the level of class 4 in accordance with international standards. [ABSTRACT FROM AUTHOR]

This paper concerns an economic and exergetic efficiency analysis of a plate heat exchanger placed in a solar installation with TiO2:SiO2/DI:EG nanofluid. This device separates the primary circuit—with the solar fluid—and the secondary circuit—in which domestic hot water flows (DHW). The solar fluid is TiO2:SiO2 nanofluid with a concentration in the range of 0.5–1.5%vol. and T = 60 °C. Its flow is maintained at a constant level of 3 dm3/min. The heat-receiving medium is domestic water with an initial temperature of 30 °C. This work records a DHW flow of V ˙ D H W , i n = 3–6(12) dm3/min. In order to calculate the exergy efficiency of the system, first, the total exergy destruction, the entropy generation number Ns, and the Bejan number Be are determined. Only for a comparable solar fluid flow, DHW V ˙ n f = V ˙ D H W 3 dm3/min, and concentrations of 0 and 0.5%vol. is there no significant improvement in the exergy efficiency. In other cases, the presence of nanoparticles significantly improves the heat transfer. The TiO2:SiO2/DI:EG nanofluid is even a 13 to 26% more effective working fluid than the traditional solar fluid; at Re = 329, the exergy efficiency is η e x e r g y = 37.29%, with a nanoparticle concentration of 0% and η e x e r g y (1.5%vol.) = 50.56%; with Re = 430, η e x e r g y (0%) = 57.03% and η e x e r g y (1.5%) = 65.9%. [ABSTRACT FROM AUTHOR]

To mitigate greenhouse gas emissions, flue gas “whitening” is conducted to promote energy conservation and emission reduction. Based on a large channel plate heat exchanger with different heat exchange plates, this paper establishes a rotary wind tunnel condensation heat exchange experimental platform to measure the physical parameters of inlet and outlet wet flue gas and obtain the average heat transfer coefficient of different plate structures. By changing the operating parameters of wet flue gas, the influencing factors of the condensation heat exchange process of the wet flue gas are studied and analyzed. The results show that within the range of 366 K–418 K, the heat transfer coefficient of wet flue gas decreases with the increase of inlet temperature. At the same inlet temperature, the lower the moisture contents of wet flue gas, the less Re affects the condensation heat transfer coefficient. At the same Re number, the condensation heat transfer coefficient of the corrugated plate is the highest. At an inlet temperature of 364 K, the heat transfer coefficient of the corrugated plate is 4% higher than that of the serrated plate and 45% higher than that of the horizontal plate. Therefore, for saturated water vapor in condensed recovery flue gas, the corrugated plate heat exchanger has the best performance. [ABSTRACT FROM AUTHOR]

A plate heat exchanger is one of the smallest and most efficient heat exchangers on the market. This experiment aims to assess the performance of methanol-water as a base fluid in a plate heat exchanger that affects the heat transfer performance. For this study, aluminum oxide (Al2O3) nanoparticle was used in various ratios (0.25, 0.5, and 0.75 vol. %) in a base fluid (10 vol.% methanol & 90 vol.% water) to prepare a nanofluid. At two different temperatures, such as 55 °C and 60 °C, with varying flow rates (2 to 8 L/min) and varying nanoparticle concentrations (0.25 to 0.75%), thermo physical characteristics and convective heat transfer studies were performed, and the results are presented. The overall inference was that there was a notable enhancement in the hot side, cold side, and overall heat transfer coefficient by the combination of Al2O3 nanoparticle and methanolwater-based fluid. It was noted that utilizing Al2O3/methanol-water nanofluid could significantly reduce the temperature gradient in the heat exchanger and improve its performance. Maximum hot fluid coefficient of 4300 W/m²°C, cold fluid coefficient of 4600 W/m²°C, and overall coefficient of 2200 W/m²°C were noted for 0.75 vol.% nanoparticle concentration and at a flow rate of 8 L/min. [ABSTRACT FROM AUTHOR]

• Heat transfer coefficient of R32 is 50 % higher than that of R410A in 1 mm chevron depth. • Heat transfer coefficient of R410A increases monotonically with mass flux, while that of R32 doesn't. • At low mass flux pressure drop of R32 exceeds that of R410A; the opposite applies at high mass flux. • Some correlations work well with R32 and R410A condensation in small gap plate heat exchangers. Compact brazed plate heat exchangers (BPHEs) with low chevron depths are widely used in new heat pumps and air-conditioners for reducing inventory and improving efficiency. This study analyses the complete condensation of R410A and R32 inside BPHEs with a chevron depth of 1 mm. The effects of the mass flux and chevron patterns (V-shaped and W-shaped) on the heat transfer coefficient (HTC) and frictional pressure drop are investigated. The HTC of R32 is 30–50 % higher than that of R410A, which has a 10–20 % higher friction factor at high mass fluxes and vice versa at low mass fluxes. The HTC of R410A monotonically increases with the mass flux, whereas that of R32 does not. The W-shaped pattern results in 30 % and 15 % higher pressure drops compared with the V-shaped pattern for R410A and R32, respectively. The friction factor of R32 decreases more sharply than that of R410A as the mass flux increases, particularly at low mass fluxes. The correlations developed by Longo et al. and Zhang et al. show the best agreement with the experimental data for the HTCs of R32 and R410A, respectively, with mean absolute percentage deviations (MAPDs) of 15 %. The friction factor correlation of Zhang et al. accurately predicts the pressure drop of R32 for the W-shaped and V-shaped patterns. In addition, it accurately predicts the pressure drop of R410A for the W-shaped pattern, with an MAPD of less than 10 %, but over-estimates it by 37 % for the V-shaped pattern. [ABSTRACT FROM AUTHOR]

• Flow boiling of R134a in a plate heat exchanger with wavy corrugations was studied. • Three major flow patterns were identified with the variation of vapor quality. • The variation of heat transfer coefficient and wall temperature were discussed. • A new piecewise Nu correlation was developed based on flow pattern transition. As a common component in various applications, the two-phase heat transfer of plate heat exchanger has been frequently studied. However, further investigations are still required on the flow pattern, especially for those with new plate structures brought with the emergence of new applications. This study presented an experimental investigation on the flow boiling of R134a in a plate heat exchanger with mini-wavy corrugations designed for thermal management system of electric vehicle (EV). The flow pattern transitions in the test section were captured and discussed, meanwhile the effects of vapor quality and mass flux on the variation of heat transfer coefficient (HTC) were analyzed. Based on the observation, the two-phase flow pattern developed from pulsating film flow, then rough stream flow and finally to thin stream flow with the increase of vapor quality. The flow pattern map was determined with the superficial momentum of the liquid and vapor phase refrigerant, while the empirical correlations were developed based on two-phase Weber number to predict the transitions between the flow patterns. The HTC showed an intermediate increase firstly under low vapor qualities, and rapidly decreased after reaching the peak value at the vapor quality of 0.45–0.6. In addition, the experimental data were compared with the present correlations, and a new Nu correlation was developed considering the transitions of flow patterns, showing an optimal prediction on the experimental data with the mean absolute error of 11.3%. [ABSTRACT FROM AUTHOR]

• Improving the seasonal performance by increasing heat exchanger size. • R32 drop-in impacts various compressor modulation strategies in distinctive ways. • Oversizing heat exchangers has larger benefits with lower range modulation strategy. • Oversizing BPHX can yield higher performance than improving the compressor motor efficiency. • Variable speed compressor at part load conditions could experience refrigerant maldistribution. The decrease in fossil fuel reserves and high energy consumption by HVAC&R equipment require the use of compressors with better efficiencies and capacity modulation strategies. Usually, seasonal performance studies focus on compressor capacity modulation methods, however the current study explores the idea of improving the seasonal performance of two compressor modulation techniques: a two-stage and a variable speed compressor with different capacity modulation ranges by using larger condensers in an R410A water ethylene glycol chiller system. The analysis shows that oversizing the heat exchangers has larger benefits with the compressor modulation strategy with lower range. Additionally, the seasonal performance estimated according to AHRI 551/591 (2020) of a two-stage compressor with oversized condenser is higher than a basic single speed compressor with a better motor indicating that oversizing brazed plate heat exchanger (BPHX) might yield higher performance than improving the compressor motor efficiency. Due to the high global warming potential (GWP) of R410A, there is a focus on replacing it with low GWP refrigerants such as R32 to reduce CO 2 emissions. This study would also compare the performance when using R32 as a drop-in refrigerant in the two different R410A compressor capacity modulation strategies with comparable cooling capacity. When the refrigerant was changed from R410A to R32, the integrated part load value (I P L V. S I), an efficiency metric for variable speed compressor remains relatively constant at 5.5 while it increases from 3.9 to 4.4 for the two-stage compressor. It is hypothesized that low refrigerant mass flow rate (m ˙ r e f) provided by the variable speed compressor when matching the load at the lower part load conditions leads to refrigerant maldistribution in BPHX and reduced I P L V. S I. [ABSTRACT FROM AUTHOR]

A reliable battery thermal management system (BTMS) is essential to ensure proper performance, a long life span and high electric vehicle safety. The primary objective of BTMS is to maintain the cells' temperature in the range of 15–35 °C while limiting the temperature spread between cells to below 5 °C. Active thermal management with polymeric hollow fibers (PHFs) has been reported in a few articles, but its tremendous flexibility is mainly advantageous for cylindrical cells. Extruded polymeric cold plate heat exchangers with rounded rectangle channels (RRCs) are proposed as a more elegant solution for planar batteries. Heat exchangers using PHFs and RRCs were experimentally compared, with a strong focus on minimizing the maximum temperature and temperature spread of the experimental setup while simultaneously achieving minimal pressure drops. The system behavior with different parameters, including materials, geometry and thermophysical properties, was further studied using properly validated CFD models. [ABSTRACT FROM AUTHOR]

Energy evaluation of the plate heat exchanger is done using Al2O3 mixed hybrid nanofluids as a coolant. The various hybrid nanofluids (AlN–Al2O3, SiC–Al2O3, and MgO–Al2O3) with equal nanoparticle ratio (5:5) and Al2O3 (10:0) of 0.01% total volume concentration and DI water act as a coolant. The impact of different nanoparticle combinations, flow rate, and inlet temperature on the heat transfer rate, pump work, performance index, heat transfer coefficient, and effectiveness is examined. It is observed that the heat transfer rate, convective heat transfer coefficient, effectiveness, and performance index enhance with an increase in the flow rate and with the addition of nanoparticles. The heat transfer rate and heat transfer coefficient improve the maximum for SiC–Al2O3 hybrid nanofluid to 3.8% and 11.7%, respectively. In contrast, pump work enhances up to 0.25% for Al2O3 (10:0) nanofluid. The effectiveness and performance index improve up to 3.9% for SiC (5:5) hybrid nanofluid. Further, a correlation to estimate the Nusselt number of base fluid has been proposed for the studied cases. [ABSTRACT FROM AUTHOR]

The paper presents an analysis of tests carried out on a titanium plate of a heat exchanger in which the flowing medium was hot gases with a temperature of 110 °C and a pH of less than 1. Strong hydrogenation of the titanium plate caused by the corrosion of the adjacent steel frame plate was detected. As a result of the synergy of the hydrogenation and erosion, a relative reduction in the thickness of the plate was observed locally by up to 94% in relation to the thickness of the titanium plate in the area not affected by degradation. The results of this study are not only of key engineering importance with regard to equipment design and the prevention of mechanical failures in titanium heat exchangers, but also with regard to equipment in other industries. [ABSTRACT FROM AUTHOR]

Energy efficiency norms require effective insulation techniques for buildings in order to minimize energy consumption. The paper presents simulations, carried out throughout the year, regarding the efficiency of energy recovery units (ER) to ensure the quality of fresh indoor air. Indoor air energy recovery calculations were performed using plate and rotary heat exchangers in different operating scenarios. The evaluated parameters led to the stability of the optimization solutions in order to obtain a higher energy efficiency on the equipment. By comparing the obtained results, optimal measures and solutions were identified for energy efficiency in the operation of ER. [ABSTRACT FROM AUTHOR]

Plate heat exchangers are widely used in the Heating, Ventilation, and Air Conditioning (HVAC) field. Cross-corrugated triangular ducts are commonly employed in plate heat exchangers. Inserting baffles into the cross-corrugated triangular ducts can improve the heat transfer performance of the plate heat exchangers. This study focuses on intricate interdependencies among the flow channel apex angle, the trapezoidal baffle inclination angle, baffle position, and Reynolds number (Re) on heat transfer and pressure drop using response surface methodology (RSM) and computational fluid dynamic (CFD). To identify the factors that maximize the Nusselt number (Nu) and minimize friction factor (f), the RSM is used to design factors, conduct numerical studies, and establish regression equations. The results show that the apex angle, baffle angle, X-direction position, and Re have significantly affected Nu and f. Compared to a non-baffled channel with the same apex angle and Re conditions, the optimized channel enhances heat transfer by 1.54 times and has an almost identical pressure drop. The inclined baffle significantly enhances comprehensive performance at low Re. The synergistic effect of the heat transfer and pressure drop is most optimal when the apex angle of the flow channel is 90°, the trapezoidal baffle inclination angle is 52.5°, and the Re is 1000, with the baffle position at 0.625H in the X-direction. [ABSTRACT FROM AUTHOR]

Agriculture is the main industry in northeast China. As an important part of facility agriculture, agricultural greenhouses are playing a more and more important role. Due to geographical location, Northeast China is cold in winter, and the solar radiation energy is less, therefore, the large-span greenhouses commonly used in northeast China are prone to uneven temperature and insufficient heating. In this paper, in order to solve the phenomenon of uneven air flow field, humidity field and temperature field in greenhouse, based on AIRPAK simulation, four kinds of hot air heating return air modes, such as upper air supply and lower air return mode, lower air supply and upper air return mode, two-side air supply mode and left air supply and right air return mode, we explored the influence of temperature field, humidity field and air flow field in greenhouse. The results showed that the heat load of the greenhouse in winter is 161.51 kW, using two-side air supply mode is the best way. The air supply wind speed is 1.6 m/s, and the return wind speed is 3.1 m/s. The environment of the greenhouse can be maintained at about 15°C day and night, and the relative humidity is relatively uniform. In the crop growing area, the wind speed is between 0 m/s and 0.25 m/s. According to this research, suitable crops can be selected for reasonable planting and distribution in the greenhouse to maximize productivity. [ABSTRACT FROM AUTHOR]

The resistance of AISI 304 and 08Kh18N10 steels to crevice corrosion in chloride-containing media was studied using potential-dynamic methods. The preset gap width of 0.3 mm between the sample and the counter body simulates the gap between adjacent plates of plate-like heat exchangers. The area of the hysteresis loop of the constructed anode potential-dynamic curves of the forward and reverse stroke was used to compare the volume of local damage caused by crevice corrosion of the studied steels. The maximum areas of the steel hysteresis loop and the volume of local corrosion damage in the ingots with the lowest (2.23×10–8 and 2.24×10–8 m3/kg) and highest (2.31×10–8 m3/kg) values of the specific paramagnetic susceptibility χ0 of austenite were established. The free corrosion potential Ecorr of steels intensively shifts in the negative direction (from –0.28 up to –0.41), and the repassivation Erp and crevice corrosion Ecrev – in the positive direction from –0.38 up to –0.29 and from –0.1 to 0.1 V, respectively, with an increase in the parameter χ0 from 2.23×10–8 up to 2.25×10–8 m3/kg, which contributes to an increase in their ∆E-criterion from 0.02 up to 0.69 V and resistance to crevice corrosion. This is because, in this range of values, the change in the χ0 parameter is determined by deviations in the content of C, N, S, P, and Cr in the solid solution of austenite in steels. With an increase in the parameter χ0 of steels to 2.31×10–8 m3/kg, their potential Ecorr shifts in the positive direction from –0.41 up to –0.32, and Erp , Ecrev – in the negative direction from 0.29 up to 0.15 and from 0.10 up to –0.02 V, respectively, which contributes to a decrease in the ∆E criterion of steels from 0.65 up to 0.14 V and their resistance to crevice corrosion. The χ0 parameter of steels is an integral characteristic of the paramagnetic state of austenite and can be used to assess their resistance to crevice corrosion in chloride-containing media. [ABSTRACT FROM AUTHOR]

Determination of the geometrical parameters of the heat exchanger has important effects on the thermohydraulic performance of the heat exchanger. In this study, the effects of geometric parameters of a plate heat exchanger on thermohydraulic performance have been extensively investigated using computational fluid dynamics (CFD). Parametric studies were performed on 8 different corrugated channel geometries with various chevron angles (β) and aspect ratios (2b/λ) for Reynolds numbers ranging from 500 to 3000. An entire fluid channel was numerically studied using the same mass flow rate and the Reynolds number. As results of the study, temperature distribution, pressure gradient, velocity, turbulent kinetic energy distribution, Nusselt number, friction factor, and flow properties were evaluated comparatively for each case. It was determined that the sinusoidal corrugations promote the turbulence intensity and the swirling flow which leads to thermal boundary layer mitigation and enhanced convection heat transfer in response to the increasing of aspect ratio. The results of the study show that the (CFD) model is a reasonable and effective technique for displaying 3D contour plots, streamlines, and determining performance parameters. [ABSTRACT FROM AUTHOR]

The fouling kinetics and amount of calcium sulfate and calcium carbonate, respectively, on different polypropylene/graphite composites in a flat plate heat exchanger are determined and compared to the reference material stainless-steel. For a straight evaluation of the fouling susceptibility of the materials the formation of bubbles on the materials is considered by optical imaging or excluded by a degasser. The results are interpreted using surface free energy and roughness of the surfaces. The results show that when bubble formation is avoided, the polymer composites have a very low fouling tendency compared to stainless steel. This is particularly the case when turbulent flows are present or when sandblasted specimen are used. Sandblasting also continues to increase heat transfer compared to untreated samples by increasing thermal conductivity and creating local turbulences. Depending on the test conditions, the fouling resistance formed on the stainless-steel surface is an order of magnitude greater than on the polymer composites. In addition, the fouling layers adhere only weakly to the composites, which indicates an easy cleaning in place after the formation of deposits. [ABSTRACT FROM AUTHOR]

Consumer safety and product quality are of high priority in the food industry. Strongly adhering deposits are formed in processing equipment such as plate heat exchangers, which demand large quantities of water, chemicals, energy and time for cleaning. This study presents an approach to characterize soil properties and to link them to the cleaning behavior to generate a basis for soil-specific cleaning. Six starch soils were rheologically analyzed during swelling, pull-off forces were measured with a micromanipulation device, and swelling progression was determined with a camera. Cleaning experiments were conducted in a plane channel setup. A reptation time without cleaning and a subsequent constant cleaning rate defined the cleaning behavior. The observed cleaning mechanisms were considered as well. Multivariate statistics revealed significant interrelationships between soil properties and cleaning behavior. The complex reasons for the overall cleaning behavior remain unknown, but certain aspects could be explained by the measured soil properties. [ABSTRACT FROM AUTHOR]

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Compact heat exchangers, commonly used in oil and gas offshore platforms, are thermal devices that promote high heat transfer rates due to a large ratio of the heat transfer surface area per volume. It is manufactured commonly through diffusion welding, a thermo-mechanical process that joins flat surfaces in contact by applying pressure and temperature, during a defined time. In this context, surface quality is a highly relevant topic since the machining process affects the surface and consequently the contact area for diffusion welding, having an impact on the quality of welding. Photochemical machining is the main process used to machine the channels in compact heat exchangers. As an alternative process to fabricate channeled plates, abrasive waterjet machining can be used, being a process where abrasive particles are accelerated through a waterjet at high speed, used to cut out parts and generate complex 2D profiles geometries with a potential to high productivity in comparison to the other process. These two-machining processes affect the surface quality of the piece, increasing the roughness, reducing the surface homogeneity with the formation of craters and other voids, which can be a source of defects and stresses and can also increase the accumulation of fouling and the tendency to corrosion in these places. To avoid these effects, it is necessary to employ postprocessing techniques to homogenize and improve the surface quality, like electropolishing that is a surface finishing process used to remove roughness through anodic dissolution and to promote a homogeneous oxide passive layer. The present work aims to compare quantitatively the surface topography of machined sheets using surface characterization techniques of electron microscopy and optical interferometry. The surface quality of the initial commercial stainless sheet was compared, as a reference, after abrasive waterjet and photochemical machining, as well as after the electropolishing of abrasive waterjet machining and photochemical machining. It was observed that abrasive waterjet machining presented burr at the channel's edge and had an approximately 35% increase in Sa parameter when compared with the initial condition. Photochemical machining, however, did not have burr at the machined region but presented a decrease in quality of more than 90% regarding the Sa parameter compared with the base material. The use of electropolishing removed the burrs from the abrasive waterjet machining and reduced surface roughness after the two machining methods, with more than 50% for Sa, Sq, and Pt, being a potential technique to be used to improve the surface integrity in both machining processes and guarantee an effective diffusion welding. [ABSTRACT FROM AUTHOR]

The strength of the joint between the heat exchange tube and the tube plate affects the performance and operation cycle of the heat exchanger. Different expansion processes were adopted for same material Q345R+10# and dissimilar materials Q345R+S30403 joints, respectively, in order to verify the performance of the joint under frequent heating and cooling during actual operation. Through theoretical calculation of expansion pressure, the same expansion pressure and similar expansion degree were applied to each group of joint specimens, and the pull-off stress of Q345R+10# joints of the same material at room temperature, 100 °C, 200 °C and 300 °C was compared, as well as the sealing and pull-off stress of Q345R+10# and Q345R+S30403 joints before and after thermal vibration. This paper mainly introduces the expansion process of the joints between heat exchanger tubes and tube plate. Mechanical and hydraulic tube expansion machines were used for tube expansion experiments, and the joint specimens were treated with heat treatment and thermal vibration to simulate the operating temperature of the equipment. The expansion quality and expansion performance of the joint were analyzed to determine the optimal expansion pressure, and the sealing performance and tensile resistance of the joint were tested, so as to provide a reference for the processing and manufacturing of the joint between the heat exchanger tube and tube plate similar to the heat exchanger. [ABSTRACT FROM AUTHOR]

The capsule-type plate heat exchanger (PHE) is a new type of equipment with great potential, which is characterized by the concave and convex capsule-like surface. In this article, new structures consisting of capsules and spherical dimples of PHE were proposed. Flow through a periodic unit cell with four different geometries is simulated numerically to characterize the pressure drop, heat transfer coefficients, and entropy generation rate. The numerical results show good consistency with the existing experimental data. Results show that the flow in capsule-type plate can be divided into recirculation zone and high-velocity zone. The staggered capsule structure and the spherical dimple shape generate more secondary and impinging flows, which provide higher Nusselt number and friction factor. The maximum Nusselt number area changed from the upwind region of capsule to the vicinity of dimple region because of the downwash effect and the fluid impact effect. The Nusselt number is enhanced by 19%–46%, and the friction factor is 1.21–2.9 times to that of the primary capsule-type plate. In addition, Entropy analysis illustrates that the maximum reduction in the dimensionless entropy generation rate is 43.6%. [ABSTRACT FROM AUTHOR]

The metals are the most popular materials for the plate heat exchangers due to high thermal conductivity. The thermal performance of the metallic plate heat exchanger is degraded by longitudinal heat conduction in the plate. For the cabinet cooling system and ventilator, the metallic plate heat exchanger can be replaced by the plastic plate heat exchanger. In this article, the longitudinal heat conduction in the plastic heat exchanger is studied by using the heat transfer models with and without longitudinal heat conduction, which were proposed in our previous work. The effects of both transverse heat conduction and longitudinal heat conduction can be considered. The thermal performances of the plastic plate heat exchanger and metallic plate heat exchanger are compared. We find out that in the plastic plate, both the transverse heat conduction and longitudinal heat conduction are weakened because of the low thermal conductivity. The high-density polyethylene plastic plate heat exchanger has better thermal performance than that of the aluminum plate heat exchanger. [ABSTRACT FROM AUTHOR]

Consideration of transient effects is important for industrial applications of heat transfer structure optimisation studies; however, the huge computational cost associated with transient problems is a pressing concern. This paper proposes an extension of a previous reduced-dimensional model to transient conjugate heat transfer between a fluid flow and solid-heated plates in a plate heat exchanger. The extended reduced-dimensional model introduces the temperature field of the plate governed by the heat conduction equation, which is coupled to the temperature field of the fluid, governed by the convection-diffusion equation, through the heat flux balance equation at the contact surface. The model is based on assumptions of fully developed flow and constant temperature profile, reducing the three-dimensional problem to a planar problem and significantly reducing computational costs. The accuracy of the model for the simulation of transient heat transfer is verified by comparison with a three-dimensional model. In this paper, the topography of the heat exchanger plate is optimised for both steady-state and transient conditions by applying the reduced-dimensional model. The effectiveness of the optimised design was demonstrated by the cross-check of both the reduced-dimensional and full three-dimensional models. Furthermore, this work considers the effect of time-independent boundary conditions and time-dependent boundary conditions on transient optimisation. The transient and steady-state optimised designs are analysed and compared for both conditions, and the necessity of transient optimisation is discussed. [ABSTRACT FROM AUTHOR]

Heat pumps driven by sustainable electricity sources have been identified as a technology that can contribute to reduce carbon dioxide emissions. Furthermore, a heat pump can also provide energy savings when combined with a thermal energy storage system. Heat pumps can optimize their efficiency by accumulating thermal energy during periods of lower electricity demand, resulting in shorter operational durations and decreased overall energy consumption. In this work, the combination of a latent heat storage system with an air-water heat pump has been numerically analysed and experimentally tested. A phase change material (PCM) heat exchanger with an immersed plate was designed using a 3D CFD model (COMSOL Multiphysics®). The heat exchanger configuration with six steel plates immersed in the phase change material tank was proposed to enhance heat transfer in the storage system. The developed model is validated against experimental data from a real case study, demonstrating a maximum error of approximately 3% during the discharging phase. Additionally, the study explores the effects of different inlet heat transfer fluid temperatures and flow rates on the PCM solidification time. [ABSTRACT FROM AUTHOR]

Plate heat exchangers are realized by means of a heat transfer mechanism, in which heat is naturally transferred from the hot substance to the object with a lower temperature according to the laws of thermodynamics. Two liquids of different temperatures flow on the wall, heat transfer on the wall and convection of the liquid on the wall, thus promoting heat transfer between the two liquids. Under the same flow rate and power consumption conditions, its heat transfer coefficient is three times that of shell and tube heat exchangers, which is a key and efficient new equipment for effectively using effective resources and saving and developing new energy. However the heat supply plate heat exchanger has a tiny circulation surface and is easily obstructed. Regular maintenance and cleaning, troubleshooting, and plate replacement all necessitate frequent heat exchanger disassembly and installation. The requirements and challenges in dismantling and assembling the heat exchanger are very high, and manual disassembly is wasteful, making consistent force difficult to achieve. The current methods of disassembly and assembly are inefficient and incorrect. The intelligent mechanization of disassembly and assembly equipment is realized in this paper by driving, clamping, automatic control, distance measurement, sensing, and other systems. The problems of uneven force, low efficiency, and precision in plate heat exchanger disassembly and assembly are solved. Our power disassembly equipment for high efficiency heat transfer plate heat exchangers not only enhances disassembly efficiency and precision, but it also ensures the safe operation of the plate heat exchanger heating system, and the heat transfer efficiency and heat exchange efficiency are improved. Furthermore, it has a wide range of applications in the petroleum, chemical, and other industries. [ABSTRACT FROM AUTHOR]