Plate-type Heat Exchanger Research Articles

A study on development of the thermal storage type plate heat exchanger including PCM layer

Thermal storage type plate heat exchanger (TSPHEs) was newly developed in the process of research a heat pump using industrial waste heat as a heat source for evaporation. A conventional plate heat exchanger is a structure in which two media perform heat transfers through a separation plate. However, TSPHEs have a structure in the basic structure of conventional plate heat exchanger adding the PCM layer filled to phase change material. Therefore, the TSPHEs performed heat exchange between three heat media (hot water-cold water-PCM). The thermal energy supplied through the hot water is mainly transferred to the cold water and some of it is transferred to the phase change material filled in the PCM layer. When if the hot water is shut down and the heat source can’t be supplied, the heat stored in the PCM layer is transferred to the cold water through the hot water, the medium of transmission. In the article, using the e-NTU method, a thermal equilibrium equation is established between the three heats media used in the TSPHEs. Based on the established theoretical formula, the relationship between total overall heat transfer coefficient and e, S (temperature differential), and Cr (heat capacity ratio) was obtained. In addition, the validity of the theoretical analysis was demonstrated through the experimental method and compared with the correlation of the existing overall heat transfer coefficient. The results of this article will be utilized as basic data for the design of the TSPHEs, and will be used to predict the amount of heat exchange and thermal storage capacity of the TSPHEs.

Fouling Characteristics of Milk-Water System in a Plate Heat Exchanger

Fouling is a major problem which affects technical performance and economics of the plate type heat exchanger used for the pasteurization of milk and dairy products. In the present work, experiments were conducted with milk- water system using corrugated plate type heat exchanger (model: M3-FG Alfa Laval) with 13 plates. Experiments were conducted to determine the heat transfer characteristics and fouling resistance by varying the temperature and the flow rate. The enhancement of heat transfer by fouling minimization with the coating of plates with epoxy coating was also studied and reported.

Pillow plate heat exchanger weld shape optimization using approximation and parallel parameterized CFD and non-uniform rational B-splines

Plate heat exchangers (PHXs) are compact with small approach temperature, and desirable thermal-hydraulic characteristics. It is greatly desirable to create novel PHX designs that utilize less material and less volume while attaining similar heat transfer performance and thus contribute significantly to energy conservation while lowering the environmental impact as well. Pillow Plate Heat Exchanger (PPHX) is a type of PHX with a complex wavy structure with desirable thermal-hydraulic characteristics, but yet an economical manufacturing process especially when compared to corrugated Chevron PHX (CPHX) which requires a special die for each design. PPHX has great design flexibility allowing novel designs to be created in a simpler and less costly process which provides them with a good potential to outperform other types of PHXs. PPHXs are more commonly used in chemical and process industry with limited research in Heating, Ventilating, Air Conditioning, and Refrigeration (HVAC&R) applications. In this study, the optimization of PPHXs in order to maximize their thermal-hydraulic performance, including weld shape optimization using novel weld shapes created using Non-Uniform Rational B-Splines (NURBS), is studied. Sensitivity analysis is conducted on the optimal designs to provide insights into factors affecting their performance. The potential enhancement is up to 36% improvement in heat transfer coefficient and 67% reduction in pressure drop as compared to a selected PPHX baseline design with circular spot welds. The optimal designs are compared to optimal CPHX designs from literature showing a potential improvement of 38% for heat transfer coefficient, and a reduction of 72% in pressure drop.

Evaluation the effects of geometrical parameters on the performance of pillow plate heat exchanger

The growing demand for energy-saving in industries has led to numerous researches to improve the heat exchangers thermal performance in a variety of methods. The pillow plate heat exchanger (PPHE) is one of the new types of plate heat exchangers that have specific functional properties compared to conventional plate heat exchangers. The objective of the present investigation is providing comprehensive information about effective geometrical parameters of PPHEs for optimal design. In the present study, the performance of PPHEs is studied by numerical simulation. The obtained results have shown that the geometrical parameters of the PPHEs have a significant effect on thermal performance. The considered geometrical parameters include the height of pillow plate channels, and the longitudinal and transversal distance of welding spots. The heat exchanger thermal performance increases by expanding the height of the pillow channel mostly at low Reynolds number. After increasing longitudinal and transversal distance of welding spots the heat transfer and friction factor decreases in both cases. However, the effect of friction factor decrement on heat exchanger performance is more than decreasing in heat transfer. Thereby the PPHE with longer longitudinal or transversal distance of welding spot is efficient.

On the thermodiffusion effect in vertical plate heat exchangers.

The subject of the transport phenomena has a pivotal role in the performance of aqueous lithium bromide falling film absorbers. Although the thermodiffusion phenomenon appears inside the solution, very little is known about its influence on the mass transport. This study numerically analyses the influence of the thermal mass transfer mechanism on a vertical plate-type heat exchanger for different Reynolds numbers ([Formula: see text]). Results indicate that, in general, the mass transfer caused by the temperature gradient enhances the total absorption because of the negative Soret coefficient of the salt solution. This improvement is found to be higher at higher Reynolds numbers. Furthermore, the concentration and temperature profiles and, therefore, the absorption change significantly along the flow length. Overall, this analysis assists the understanding of the role of the thermal mechanism in this type of absorbers and it demonstrates that it should be considered in future studies.

폐열수 유량에 따른 축열식 판형 열교환기의 축열 및 방열 특성

폐열수 유량에 따른 축열식 판형 열교환기의 축열 및 방열 특성

Comparison of different ORC typologies for heavy-duty trucks by means of a thermo-economic optimization

This study focuses on the design phase of ORC systems recovering the heat wasted from two of the sources available on a Heavy-Duty Truck (HDT): the exhaust and recirculated gases. From these heat sources and their combinations, 5 possible architectures are considered. The main components (i.e. the heat exchangers, the pump and the expander) of the WHR systems are investigated and modeled. Plate type heat exchangers are considered for both the hot and cold sides of the system. Regarding the expansion devices, 5 positive displacement machine technologies, the scroll, screw, piston, vane and roots expanders, are considered and modeled while, among the turbo-expanders, the radial-inflow turbine is taken into consideration. A semi-empirical model is proposed to simulate a volumetric pump. The models of components are first confronted with experimental data. The validated models are then used as references for the design of the new components, which is achieved following similitude rules. This ultimately leads to 30 typologies that will be used with 6 of the various investigated working fluids. In order to identify the most promising system(s), a 3-step optimization tool is developed. First, the most suitable conditions are identified for the design of the ORC systems using a simplified model of an expansion machine. In the second step, the design phase, using more detailed models for the expanders and a proposed economic model for the overall system, a thermo-economic optimization is performed. In the third step, the output power for each of the obtained system models is maximized, optimizing the evaporating pressure and the superheating degree for various off-design conditions. The average power weighted using the frequency distribution of the gas operating conditions is computed and used to compare the 180 systems. Finally, because power is not the only criterion to select the most suitable system topology, additional criteria are taken into consideration.

Heat transfer enhancement in pillow-plate heat exchangers with dimpled surfaces: A numerical study

Pillow-plate heat exchangers (PPHE) represent an innovative, fully welded plate-type heat exchanger. They consist of a stack of panels, which are characterized by “pillow-like” surface. The waviness of the channels enhances mixing in the fluid boundary layers, which consequently augments heat transfer. However, PPHE need further optimization in order to compete with corrugated plate heat exchangers with respect to compactness. In this study, a method to enhance heat transfer in PPHE is proposed, based on a surface modification of pillow plates by secondary dimple structures on their primary wavy surface. The new structured surface of the pillow plates promotes stronger near-wall mixing.

Numerical Study on Thermal Hydraulic Performance of Supercritical LNG in Zigzag-Type Channel PCHEs

In this paper, we study a promising plate-type heat exchanger, the printed circuit heat exchanger (PCHE), which has high compactness and is suitable for high-pressure conditions as a vaporizer during vaporization. The thermal hydraulic performance of supercritical produce liquefied natural gas (LNG) in the zigzag channel of PCHE is numerically investigated using the SST κ-ω turbulence model. The thermo-physical properties of supercritical LNG from 6.5 MPa to 10MPa were calculated using piecewise-polynomial approximations of the temperature. The effect of the channel bend angle, mass flux and inlet pressure on local convection heat transfer coefficient, and pressure drop are discussed. The heat transfer and pressure loss performance are evaluated using the Nusselt and Euler numbers. Nu/Eu is proposed to evaluate the comprehensive heat transfer performance of PCHE by considering the heat transfer and pressure drop characteristics to find better bend angle and operating conditions. The supercritical LNG has a better heat transfer performance when bend angle is less than 15° with the mass flux ranging from 207.2 kg/(m2·s) to 621.6 kg/(m2·s), which improves at bend angle of 10° and lower compared to 15° at mass flux above 414.4 kg/(m2·s). The heat transfer performance is better at larger mass flux and lower operating pressures.

Performance assessment of a marine freshwater generator through exergetic optimization

The objective of this study is to examine the effect of operating parameters on the freshwater generation capacity of a vacuum type and low-temperature single-stage freshwater generator and the exergy destruction of the condenser and evaporator sections. Evaporator and condenser, which are plate type heat exchangers, are modeled using the ε-NTU method. Energy and exergy analyses were applied to the control volume enclosing the condenser and evaporator to find the freshwater production rate and to investigate the system performance. A parametric study was performed to assess the effects of the jacket water mass flow rate, the seawater salinity, and the seawater temperature on the output parameters (fresh water production rate and specific exergy destruction). In addition, an optimization study was performed using the Taguchi method to maximize the freshwater production rate and minimize the exergy destruction rates of the condenser and evaporator. The results derived from the parametric study showed that the seawater temperature of 31.88 °C and jacket water mass flow rate of 72,000 kg/h are the required values to obtain the maximum freshwater generation capacity (30 m3/day). When the salinity increases from 3 g/kg to 41 g/kg (3000 to 41,000 ppm), the freshwater production rate increases by 2.18% and 5.06% under the constant seawater temperature (23 °C) and the jacket water mass flow rate (58,500 kg/h), respectively. The optimization results revealed the conditions to obtain the maximum fresh water production rate and the minimum exergy destruction.

Characteristic analysis and structure optimization of a type of plate heat exchanger

In this work, the single-phase heat transfer and flow characteristics in a type of plate heat exchanger considering water as working medium are numerically simulated and analyzed, which agree well with experimental results. To further optimize the plate structure, eight cases for three exchanger factors including corrugation inclination, corrugation normal pitch and corrugation depth are selected using uniform experimental design method for investigation. Based on the results, the regression equation of comprehensive heat transfer performance factor Ψ is proposed. The Ψ reaches the maximum in the condition of β = 110°, P=5.8mm, b=3.2mm and increases by 31.27% compared with Ψ0 in the initial condition.

Heat exchanger design studies for molten salt fast reactor

In this study, conceptual design for primary heat exchanger of the Molten Salt Fast Reactor is made. The design was carried out to remove the produced heat from the reactor developed under the SAMOFAR project. Nominal power of the reactor is 3 GWth and it has 16 heat exchangers. There are several requirements related to the heat exchanger. To sustain the steady-state conditions, heat exchangers have to transfer the heat produced in the core and it has to maintain the temperature drop as much as the temperature rise in the core due to the fission. It should do it as fast as possible. It must also ensure that the fuel temperature does not reach the freezing temperature to avoid solidification. In doing so, the fuel volume in the heat exchanger must not exceed the specified limit. Design studies were carried out taking into account all requirements and final geometric configurations were determined. Plate type heat exchanger was adopted in this study. 3D CFD analyses were performed to investigate the thermal-hydraulic behavior of the system. Analyses were made by ANSYS-Fluent commercial code. Results are in a good agreement with limitations and requirements specified for the reactor designed under the SAMOFAR project.

Investigation of Plate-type Heat Exchanger using Latent Heat Thermal Storage

Investigation of Plate-type Heat Exchanger using Latent Heat Thermal Storage

Plate type heat exchanger for thermal energy storage and load shifting using phase change material

The study presents an experimental investigation of a thermal energy storage vessel for load-shifting purposes. The new heat storage vessel is a plate-type heat exchanger unit with water as the working fluid and a phase change material (PCM) as the energy storage medium. The thermal characteristics of the heat exchanger such as heat transfer coefficient, effectiveness, efficiency, water exit temperature, heat storage rate, total energy storage capacity and storage time were experimentally evaluated as a function of various inlet conditions. The compact parallel plate design showed an enhanced the performance compared to conventional storage systems with an effectiveness up to 83.1% even when a PCM of low thermal conductivity is used. The proposed phase change energy storage system not only can deliver substantial benefits as a thermal energy storage medium, but also provides cost savings in infrastructure, equipment, and maintenance/operations compared to conventional systems.

Thermal performances of a multi-scale fluidic network

This paper presents an original study on the heat transfer characteristics of a multi-scale structured fluidic network consisting of a number of minichannels in parallel. Two sets of application are tested, including a single plate heat sink being heated on its base surface and a two-stream plate-type heat exchanger when several such plates are stacked one above another. Computational Fluid Dynamics (CFD) simulations were performed to characterize local temperature profiles and thermal performances in such a complex geometry. In parallel, a prototype made of Aluminum was fabricated and tested, providing experimental results for comparison and validation of the obtained numerical results.Results indicate that when used as a heat sink for cooling purpose, the overall thermal resistances of the multi-scale structuration concept are remarkably smaller than some micro- or mini-channels heat sinks tested in the literature. When used as a novel two-fluid plate-type heat exchanger, the volumetric heat transfer power could reach about 25 MW m−3. This novel concept of multi-scale structured plate heat exchanger showcases how to design and develop globally macro-sized, locally micro (milli)-structured process equipment while keeping high performances, aiming at large-scale industrial applications.

Simulation for evaporative cooling in partially wetted plate heat mass exchanger

The thermal characteristics of a M-cycle counter flow type plate heat exchanger (PHE), intended for use as a cooler, has been investigated numerically as an indirect evaporative cooler. For a fixed heat exchanger length (L = 50d) and the space between plates (d = 6 mm), the investigation included a numerical simulation for the PHE and the study of its performance with the variation in the number of the wetted zone (n) from 1 to 16 for inlet Reynolds number Re = 200. The computational results indicate that the heat exchanger performs better with the number of the wetted zone, high inlet air temperature and low relative humidity. Results show that the cooler consumes less water and it is an environmentally friendly cooler for dry areas.

Development of an additive manufacturing-enabled compact manifold microchannel heat exchanger

This paper discusses the design and performance characterization of a compact tubular manifold microchannel heat exchanger. The purpose of this study was to explore the role of more precise flow distribution in the heat exchanger utilizing an additively manufactured manifold for single-phase flow under low to moderate heat flux conditions. The heat exchanger uses a commercially available enhanced tube having a fin structure on its outer surface and helical pattern of grooves (rifling structure) on the inner bore of the tube. A 3D printed manifold made of ABS plastic was used to properly distribute the flow on the shell-side of the heat exchanger. Water was used as the working fluid for both shell and tube-sides. Single-phase experimental tests showed an overall heat transfer coefficient of 22,000 W/(m2K) and shell-side heat transfer coefficient of 45,000 W/(m2K) for the shell-side and tube-side water flow rates of 82 g/s and 806 g/s, respectively. The shell-side heat transfer coefficient was found to be an order of magnitude higher than that found in typical shell and tube and plate-type heat exchangers.

Determination of Optimum Concentration of Nanofluid for Process Intensification of Heat Transfer Using Corrugated Plate Type Heat Exchanger

Abstract In this study cooling of hot water is taken up using a compact heat exchanger such as corrugated plate type heat exchanger and with utility fluid as a nanofluid prepared from mixing Al2O3 in water. In general a monotonic increase of 30 % to 70 % in overall heat transfer coefficient is observed for increase in nanofluid concentration as well as its flow rate. An optimum concentration of nanofluid is hence not possible to be found as heat transfer coefficient exhibited a monotonic trend. But there is a penalty for using nanofluid of higher concentrations in heat exchangers in the form of additional hydraulic power required to supply the nanofluid due its higher viscosity. Hence, as a novel approach, a target temperature drop of 15 °C for hot fluid (with constant flow rate) is assumed and the minimum critical flow rate of cold nanofluid of various concentrations required for achieving this is determined using simulation. For such a critical flow rate at various nanofluid concentrations, the determined hydraulic power (product of pressure drop and flow rate) exhibited a global minimum around 0.75 % volume concentration of Al2O3 in water. Thus this article presents the process intensification procedure for the heat exchangers using nanofluids as heat transfer enhancement option.

Experimental and numerical investigations of thermal performance of Al2O3/water nanofluid for a combi boiler with double heat exchangers

Purpose This study aims to focus on usage of Al2O3/water nanofluid as working fluid in a combi boiler. The plate heat exchanger located at the bottom of the combi boiler has been used for heating the domestic water in the present study. Al2O3/water nanofluid has also been used in obtaining of the heat energy provided from combustion. Therefore, thermal performance of Al2O3/water has been determined by comparing water and nanofluid-water mixture. The present study also investigates heat transfer rates as numerical and experimental for varying cold side outlet temperatures, comparatively. Design/methodology/approach The present study has included both experimental and numerical methodologies. The experimental setup consists of main heat exchanger, atmospheric burner, circulation pump and plate-type heat exchanger in which the Al2O3/water nanofluid was used as working fluid to heat the domestic water. In the numerical part of the study, a commercial computational fluid dynamic code has been used to model heat rate and thermal efficiency of the heat exchanger used. Findings It has been concluded that the predicted results are in satisfactorily good agreement with the measured data. In the experimental part of the study, the flow rate of Al2O3/water nanofluid was kept constant during the experiments. The flow rates of the water by which the heated Al2O3/water nanofluid mixture was cooled via the plate heat exchanger have been changed as 3, 4, 5 and 6 lpm. The domestic water temperatures that were kept constant have also been changed as 40°C, 45°C, 50°C, 55°C and 60°C. It has been concluded that the Al2O3/water nanofluid thermal efficiency has been 16 per cent better than pure water. Originality/value The main originality of the present study is that thermal efficiency of the plate-type heat exchanger when Al2O3/water mixture nanofluids are used as there are limited studies related to the usage of Al2O3/water mixture nanofluids in the plate-type heat exchanger not only experimental but also numerical methodologies.

Literature survey and a universal evaporation correlation for plate type heat exchangers

Plate heat exchangers are widely used in the industry. Being compact in nature, they are good candidates to be used as evaporators with reduced charge. A review of the existing evaporation heat transfer coefficient data for plate heat exchangers has been carried out. The literature survey also includes compilation of available Nusselt number correlations. In this work, an attempt has been made to develop a universal Nusselt number correlation that can be used to predict the heat transfer coefficient during evaporation of several key refrigerants using various plate geometries. The predicted values of Nusselt number using proposed correlation were found to be in good agreement with the experimental data of ammonia (R-717), R-134a, R-410A and few relatively new refrigerants. The proposed correlation is valid for 313 < Reeq < 12,700, 0.000136 < Boeq < 0.0019 and is shown to predict the actual data within ±30% error. The predicted heat transfer coefficient was also found to be in good agreement with results from the major plate exchanger manufacturers.