Rectangular Fins Research Articles

Effective performance on refrigerators based on fined tuned evaporator optimization by various mixtures in an air conditioning system

This research paper proposes the evaporator utilized an air-conditioning structure or refrigeration for allowing the condensed cooling substance like Freon or R-134A, to vanish as of fluid to gas though absorbing temperature in the development and also utilized for removing the water or other fluids present in system mixture. In this paper, the isotropic mixture of R134A & R160 we are taken, R134A As a base fluid mixing by R160 with concentrations of 0 % , 20 % , 40 % , 60 % , 80 % a n d 100 % or else it is utilized in a Refrigeration unit by various flow rates by means of fitting the added contributed limitations such as a pressure and temperatures are constant in evaporator. The fin tube evaporator is designed in 3D modeling software CATIA. The fins measured by rectangular fin, Hexagonal Fin and circular fin. The huge flow rate and heat transfer rate are examined by using CFD technique in ANSYS software. Thermal investigation conducted on evaporator with different materials such as aluminum alloy 7475, copper and brass.

Experimental Study of Using Passive Cooling of the Photovoltaic Module Under Hot Climate Conditions

Exposure of the photovoltaic (PV) module to more quantity of solar radiation with high ambient temperatures during operation causes their overheating that decreases the output power and efficiency of the PV module. The present study investigates the influence of using rectangular aluminium fins (RAFs), cotton wicks with water (CWWs) attached at the backside as passive cooling on productivity, efficiency, and thermal behavior of the photovoltaic PV modules. The experiments were conducted in three cases under hot weather conditions to characterize the better performance of the PV module with the use of passive cooling. The experiment results indicate that the used CWWs achieved better cooling for the PV module due to the moist condition of the cotton bristles immersed in water which provided adequate cooling that enhanced performance. On the other hand, a limited improvement was obtained in the PV module performance by used RAFs due to an increment in the surface area of the heat transfer of the PV module. A significant deterioration in the PV module performance without cooling negatively affected the performance.

Effects of base angle and wettability of nanostructures on droplet wetting behaviors

The wetting modes of droplet on nanostructure surface including Cassie, Partial Wenzel, and Wenzel are of great importance in enhancing the condensation heat transfer, surface self-cleaning and oil-water separation. Previous studies focused mainly on the behaviors of droplets on the surface of nano-pillar structures. In this work, the wetting behaviors of argon nanodroplet on platinum surface is investigated by the molecular dynamics simulations. The effects of nanostructure geometry parameters and characteristic contact angle <i>θ</i><sub>e</sub> on the wetting mode and the transition between different modes are investigated. The three-dimensional simulation box includes a bottom wall containing trapezoid wires (TWs) with different geometry parameters and other five surfaces. The TWs are populated on the wall based on the array arrangement. The periodic boundary conditions are imposed on the four side surfaces of the simulation box. The base angles of the side surface of TW with respect to horizontal plane are chosen as 60° (inverted TW), 90° (rectangular pin fin) and 120° (TW), respectively. For all the three base angles, the nanostructure surface can be completely wetted by liquid, behaving as the Wenzel mode when <i>θ</i><sub>e</sub> < 118°, under which the gaps of nanostructures are filled with liquid. However, when the characteristic contact angle <i>θ</i><sub>e</sub> is in a range of 118°–145°, the base angles of nanostructures have different effects on wetting modes. The surface with inverted TWs (60° base angle) is conducive to keeping droplet in Cassie mode, in which the liquid does not penetrate into any gap of nanostructures. The surface with rectangular pin fins behaves as either Partial Wenzel mode or Cassie mode. The transition between the two modes takes place at <i>θ</i><sub>e</sub> ～130°. The surface with TWs (120° base angle) keeps the droplet in Partial Wenzel mode, in which the gaps of nanostructures are partially wetted by liquid. For <i>θ</i><sub>e</sub> larger than 145°, the dewetting process takes place on the surface of the nanostructure, in which the droplet leaves the solid surface. We conclude that the wetting modes on nanostructured surface satisfy the minimum surface energy principle. Our work discloses a new finding that the surface with inverted TWs is easy to maintain Cassie mode, which is good for dropwise condensation applications.

Design and Assessment of Lead–sCO2 Intermediate Heat Exchanger for LFRs

Lead–sCO2 intermediate heat exchanger (IHX) was designed for lead-cooled fast reactor (LFR). The reactor coolant is lead and flowing through a circular straight channel, meanwhile, sCO2 is heated through 5 channels with different geometries were investigated respectively, including straight channel, zigzag 52° channel, S-shaped fins, offset rectangular fins, and airfoil fins. Considering the thermal-hydraulics characteristics, mechanical structure, corrosion, and flow blockage in the IHX designs, the performance, total cost, and power density of several heat exchanger designs were evaluated and compared. Finally, a printed circuit heat exchanger (PCHE) design using the circular straight (lead) - offset rectangular fins (sCO2) channels was proposed. The straight and S-shaped channels for sCO2 flow were recommended as alternative designs under certain circumstances. However, S-shaped fins and zigzag channels will dramatically increase the cost while straight and airfoil channels will greatly increase the volume.

Enhancement of solar still productivity using absorber plate with inclined perforated rectangular fins: an experimental study with economic analysis

Enhancement of solar still productivity using absorber plate with inclined perforated rectangular fins: an experimental study with economic analysis

Heat transfer enhancement of rectangular fins with circular perforations

Heat transfer augmentation devices like fins have been around for quite long time. Because of the increased demand for lightweight, thin, and cost-effective fins, fin size optimization is important. As a result, fins must be designed to extract the most heat with the least amount of material while keeping the fin’s ease of manufacture in consideration. The enhancement in heat transfer coefficient is related to the resetting of the thermal boundary layer for each disturbance. Perforated plates in fins are examples of surface disturbance. The aim of this research is to analyze the temperature reduction over a variety of circular perforations. Numerical simulation (ANSYS Fluent code) is employed to examine fins with perforations. A FVM code is used to solve turbulent air flow and heat transfer equations across fins. Over a continuum of circular perforation counts, other variables such as heat flux and thermal gradient are compared. It was observed that there was a significant temperature drop as well as an improvement in heat transfer. The results can be extended to the design of rectangular fin heat exchangers.

CFD-Based Simulation and Analysis of Hydrothermal Aspects in Solar Channel Heat Exchangers with Various Designed Vortex Generators

The hydrothermal behavior of air inside a solar channel heat exchanger equipped with various shaped ribs is analyzed numerically. The bottom wall of the exchanger is kept adiabatic, while a constant value of the temperature is set at the upper wall. The duct is equipped with a flat rectangular fin on the upper wall and an upstream V-shaped baffle on the lower wall. Furthermore, five hot wall-attached rib shapes are considered: trapezoidal, square, triangular pointing upstream (type I), triangular pointing downstream (type II), and equilateral-triangular (type III) cross sections. Effects of the flow rates are also inspected for various Reynolds numbers in the turbulent regime (1.2 × 104–3.2 × 104). The highest performance (η) value is given for the II-triangular rib case in all Re values, while the square-shaped ribs show a significant decrease in the η along the achieved Re range. The η value at Remax is 2.567 for the II-triangular roughness case. Compared with the other simulated cases, this performance is decreased by about 3.768% in the case of I-triangular ribs, 15.249% in the case of III-triangular ribs, 20.802% in the case of trapezoidal ribs, while 27.541% in the case of square ribs, at the same Remax. Also, a comparison is made with air-heat exchangers that have non-rough walls and contain cross-shaped VGs presented previously, in order to highlight the effectiveness of the rough surface presence in the baffled and finned channels. The obtained results indicated that the triangular-shaped rib (type II) has the most significant hydrothermal behavior than the other cases. This indicates the necessity of roughness heat transfer surfaces for finned and baffled channels to improve significantly the performance of the air-heat exchangers they contain.

Thermal Analysis of Solar Air Heater with Ventilator Turbine and Fins

Solar air heater (SAH) is a renewable energy application for the drying process. SAH has a challenge to produce high performance under uncertain weather. The performance of SAH can be enhanced by providing the absorber plate by adding the fins. This study aims to evaluate the thermal performance of SAH with rectangular fins SAH at low air velocity. This study compares the performance of SAH without fins and SAH with rectangular fins. Two variations of a tilt angle of SAH are 0° and 30° which are observed in this study. The SAH uses a ventilator turbine to suck air into the collector box. The air velocity is 0.01 m/s. The method is experimental. The SAH is tested under real condition from 9 a.m. to 4 p.m. The measurement tools consist of a pyranometer, an anemometer, a temperature sensor in the inlet section, 3 sensors in the absorber plate, a sensor in the outlet section, 6 temperature sensors in the drying cabinet. The result showed the thermal efficiency of SAH with rectangular fins is 29.67 % higher than SAH without fins at 0˚ tilt of angle at noon. The thermal efficiency of SAH with rectangular fins is 25.26 % higher than that of without fins at 30˚ tilt of angle at noon.

Combined influence of fin, phase change material, wick, and external condenser on the thermal performance of a double slope solar still

This study focuses on the enhancement of potable water productivity of an active double slope modified solar still (SS) considering the combined effect of solid rectangular fin, paraffin wax as a thermal energy storage medium, black cotton cloth as wick material, and an external condenser. The performance of three double slope SSs (modified, finned, and traditional) is evaluated considering five different cases. A comparative assessment of the performances of three double slope SSs is performed and it is perceived that the supreme productivities are 3.07, 2.70, and 2.46 L/m2 for modified, finned, and traditional SSs, respectively. The maximum efficiency of the modified SS with and without external condenser are found as 39.74% and 30%, respectively. An external condenser insertion in the modified SS boosts the productivity by approximately 10%. The average daily efficiency of the modified SS is 14.23% and 22.33% higher than the finned and traditional SS, respectively. The economic analysis is also conducted, and the cost per liter (CPL) values for traditional SS, the finned one, and the modified one are found as 0.0135, 0.0133, and 0.0117 $/L/m2, respectively. The novel modification of SS could be a propitious alternative to meet up the potable water demand in remote regions with low cost.

Dynamic characteristics of a shell and plate particle‐SCO 2 moving packed bed heat exchanger with various SCO 2 channel configurations

This article proposes a dynamic analysis framework for a shell and plate particle-SCO2 moving packed bed heat exchanger (MPBE) with straight SCO2 channel and four fins-modified SCO2 channels, which contains a static model and a dynamic model. 13 cases covering an initial temperature deviation range of +50 ~ −100 K from design-point case in solids inlet, an initial temperature deviation range of +50 ~ −100 K from design-point case in SCO2 inlet, and a SCO2 inlet velocity range of 1.5 times to 0.05 times are introduced to measure the dynamic characteristics. Dynamic responses of five MPBE configurations to two types of inputs (step-change perturbations and linear-change perturbations) under 13 cases are analyzed. Relaxation times at each case are summarized and compared. A low threshold temperature exists for all five MPBE configurations to avoid oscillations in solids outlet temperature under step-change perturbations in solids inlet temperature, and a low threshold SCO2 inlet temperature just appears in MPBE with straight SCO2 channels under step-change perturbations in SCO2 inlet temperature. Improved MPBE configurations show apparent less relaxation time than MPBE with straight SCO2 channel. Among four fins-modified MPBE configurations, MPBE channels modified with offset rectangular fins on SCO2 side exert the fastest dynamic characteristic in most cases.

Effect of two different fins (longitudinal-tree like) and hybrid nano-particles ([formula omitted]) on solidification process in triplex latent heat thermal energy storage system

To tackle global warming, a reliable storage system seems crucial due to unpredictability of renewable energy. As a result, storage units based on Phase Change Material (PCM) are found to be of great worth where latent heat transfer occurring in an almost isothermal condition lay the foundation for far more compact and easy-to-fabricate storage components. Despite their advantageous, one major drawback being weak thermal conductivity needs to be addressed. So, in this study a triplex-tube heat exchanger with tree-like and rectangular fins along with hybrid nanoparticles made of MoS2-TiO2 are put into perspective to dispose of this weakness and Galerkin Finite Element Method (GFEM) is applied using FlexPDE to analyze the solidification process and evaluate the influence of single and combined usage of fins and nanoparticles. Moreover, the credibility of this study and GFEM has been confirmed by an experimental work. The results unveiled that, while the combined usage of nanoparticles and tree-like fins gives the best result by lowering the solidification time by 78% compared to bare tube, tree-like fins claim the best performance taking 1700 s followed by rectangular fins with 3500 s if nanoparticles are out of reach.

Optimization of phase change thermal storage units/devices with multichannel flat tubes: A theoretical study

Collector storage solar water heater systems that use phase change materials as heat storage media have attracted increasing attention because of their clean, pollution-free properties and high energy storage density. The design and application of these systems require efficient and optimized phase change thermal storage units (TSUs). This study aims to optimize a TSU by using theoretical analysis methods and to fill the research gaps attributed to the lack of theoretical analysis. The TSU in this work comprises a multichannel flat tube and rectangular fins as heat exchange elements. The performance levels of this TSU, including its effectiveness, compactness factor, gravimetric specific power, and fin efficiency, under different structures are compared. The economic viability and energy efficiency of the proposed solar collector phase change thermal storage system are preliminarily evaluated. Results indicate that the structure of the multichannel flat tube TSU is relatively reasonable when the fin aspect ratio (Hfins/x) and thickness are 8.60 and 0.001 m, respectively. The effectiveness of the optimized TSU during charge and discharge processes respectively increases by 52.0% and 16.3% relative to the original multichannel flat tube TSU. The corresponding recommendation for the use of multichannel flat tube TSUs in household baths is four groups/person.

Numerical analysis of solar air collector provided with rows of rectangular fins

The most promising collector must achieve the best thermal efficiency and fill out high requirements of low weight, low power consumption, ease of manufacturing, and low cost. In this study; a novel efficiently optimized flat plate solar air collector is modeled with a selective absorber and three rows of rectangular fins installed beneath the structure that provides 81% of thermal efficiency and 0.5 W of pumping power. A three dimensional CFD model of a flat plate solar air collector is developed and solved in steady-state conditions. We propose a suitable approach for assessing and optimizing a 1.28 m2 surface collector’s performance with forced convection flow. Results indicate that additional fin rows (from 35 rows to 142 rows) and fins relative height (0.5 to 0.8) with a nonselective absorber increase the thermal performance from 63% to 80%, and additional turbulent flow causes an increase of pump power from 1.8 W to 16 W. The adoption of a selective absorber contributes to efficiency 5% higher than that of a collector with 35 rows of fin for a volume flow of 85.33 m3/hm2. In contrast, the gain achieved by adding 142 rows of fin (l’/L=0.006) remains the most important, where it leads to an effective efficiency of 79.2% for a volume flow rate of 85.33 m3/hm2. Thus, it has been proposed to combine the selective absorber with the addition of rectangular fins in the new design.

Investigation experimentally the impact of condensation rate on solar still performance at different thermal energy storages

In this paper, an experimental investigation is performed on the impact of condensation rate of solar still condenser at different thermal energy storage materials on the performance of single slope passive solar still. The condensation rate is changed by installing different designs of the still condenser: (i) glass plate condenser, GC, (ii) corrugated aluminum sheet heat sink condenser, CHS, (iii) aluminum heat sink condenser having vertical rectangular fins at its outer surfaces RHS, (iv) aluminum heat sink condenser having pin fins at its outer surface, PHS, (v) aluminum heat sink condenser having pin fins at its outer and inner surfaces, DPHS. Two different thermal energy storage materials inside the still basin are used; sand and black wool fibers (BWF) plus pure saline water which yield different evaporation rates of the saline water. The findings show that increasing the heat transfer rate (HTR) by the condenser increases the still yield to a limit and then decreases this yield at higher rates. Moreover, increasing the evaporation rate by using thermal energy storage material reduces the negative impact of high condensation rate. The still yield of GC is the minimum while the still yield in case of PHS has the maximum production. Solar still with PHS condenser achieves maximum yield increments of 54%, 63%, 76% in case of saline water only, sand, and BWF medium in the basin, respectively compared to the case of GC condenser with saline water only (conventional still) in the basin. The conventional still has the minimum efficiency of 23.3% and the still with PHS condenser and BWF achieves the maximum still efficiencies of 40.7%. Moreover, enhancement of HTR through using of DPHS condenser reduces the still efficiency to 29.2%, 34.3%, and 37.5% in case of pure saline water, sand, and BWF, respectively. Using PHS condenser with BWF in the still basin reduces the freshwater yield cost by about 21% compared to conventional still.

Flow Prediction and Conjugate Heat-Transfer Analysis of a Counter Flow Heat-Exchanger with Protruded Fin

Voluminous cram has been carried out in this project which is intended to improve the conjugate heat-transfer performance of a heat-exchanger. In this study, CFD method is effectively used to predict the effect of Protruded Fins in heat exchanger, which protrudes inside the tube in addition to the shell side. CFD analysis on Protruded Finned Heat Exchanger (PFHE) is carried out with three different fin configurations like rectangular, triangular and parabolic fins. The baseline model of counter flow shell-tube heat-exchanger is considered with standard dimensions and analyzed initially without fins. Later the numbers of fins are increased to optimize the fin position and counts. The shape of the fins is then modified to find an optimized model with a higher heat-transfer coefficient. Hence, the present conjugate heat-transfer and flow analysis focus on optimizing the number of fins for a heat-exchanger with counter flow along with the shape optimization of fins. The computational values are measured with the net heat exchange between the cold and hot-fluids in terms of temperature difference. Also, the area averaged surface heat transfer co-efficient (h) of the heat exchanger with different fin configurations are plotted and compared.

Energy, exergy, economic and environmental assessment of using different passive condenser designs of solar distiller

An assessment of using different passive condenser designs of the solar distiller based on productivity, exergy, energy, energyeconomic, exergyeconomic, enviroeconomic is investigated experimentally. Five different condenser designs are considered; (i) glass plate condenser, GC (CSS), (ii) corrugated aluminum sheet heat sink condenser, CHS, (iii) aluminum heat sink condenser having vertical rectangular fins at its outer surfaces, RHS, (iv) aluminum heat sink condenser having pin fins at its outer surface, PHS, and (v) aluminum heat sink condenser having pin fins at its outer and inner surfaces, DPHS. The findings show that augmenting the rate of condensation by varying the condenser design increases the still yield to a limit and then decreases this yield at a higher condensation rate. CSS has the smallest freshwater yield and still with PHS has the maximum production with an increment of 54 % comparing with GC condenser. The maximum increase of the daily average energy and exergy efficiencies of the still is about 55.3 % and 73.1 %, respectively in case of PHS condenser compared with CSS. Still with DPHS condenser has the maximum production cost while the still with PHS or CHS condenser has the minimum. Distiller with PHS condenser is the best system in achieving CO2 reduction benefits of 1.82 tons CO2/year.

Entropy Analysis of a Simple Rectangular Radiating Fin for Space Applications

For growing interest in planetary exploration, it is substantial to study the utilization of energy for future-built planetary settlements, as energy resources are at a premium far away from earth. Entropy analysis is proposed as a suitable tool to study these systems, and make them energy efficient. Hence, a simple, purely radiating rectangular fin is studied by entropy generation analysis. The distribution of temperature and radiosity of the fin is first obtained by solving the governing heat transfer equation by second order finite difference numerical analysis. Using these data, the heat transfer and entropy generation of fin, fin-base, and the surrounding space is calculated. The effect of solar irradiation on the heat transfer of fin is also considered. The influence of pertinent, non-dimensional parameters on the total rate of entropy generated by the fin system is analyzed. Further, a correlation with these parameters is obtained for the total entropy generation.

Melting Behavior of Phase Change Material in a Solar Vertical Thermal Energy Storage with Variable Length Fins added on the Heat Transfer Tube Surfaces

This paper investigates the melting behaviour of phase change material (PCM) in a vertical thermal energy storage system with provision of thin rectangular fins of uniform and variable lengths on the heat transfer tube surfaces. The selected PCM and heat transfer fluid (HTF) are paraffin wax and water, respectively. The HTF is passed through the helically coiled copper tube of 10 mm diameter to melt the PCM. The time required to complete the melting of PCM in the system with fins is found to be five hours, whereas for the system without fins it is five hours and forty minutes, for the same conditions of constant water temperature of about 70°C and flow rate of 0.02 kg/s. HTF tube with fins is observed to be more effective with a 13.33% faster rate of melting when compared to that of the HTF tube without fins. Such a fast charging process will be helpful in storing maximum energy within a short period/duration of time shorter duration in for solar thermal and heat recovery applications during lean production times. ©2020. CBIORE-IJRED. All rights reserved

Analysis of Cooling Efficiency Using the Biot Number of a Rectangular Fin

The performance of a rectangular fin, the relative value of the performance for L=0.1, and the ratio of the heat transfer from the fin tip to the total heat transfer from the rectangular fin were investigated using a two-dimensional analytical method. The variables are the Biot number and non-dimensional fin length. The relative resistance, effect, and efficiency increase as the non-dimensional length increases for a small Biot number (Bi≤0.1). On the other hand, the relative resistance and effect decrease and the relative efficiency increases as the non-dimensional length increases for a large Biot number (Bi≥0.7).

Analysis and optimization of the closed-adsorption heat storage bed performance

Sorption heat storage attracts considerable attention because its relatively high theoretical energy density compared to other heat storage methods offers various opportunities in the design of renewable and sustainable energy systems. However, limited heat transfer in the material bed remains one of the main limitations of a successful introduction to the market. In the present study, a mathematical model of the heat and mass transfer processes inside an adsorption bed of silica gel embedded with cylindrical and rectangular fins has been developed. A systematic analysis has been conducted to augment thermal transport in the adsorption bed with rectangular and pin fin configurations. A parametric study has been conducted for both fin configurations at different bed heights (δb), fin diameters/thicknesses (ϕfin/δfin) and fin spacings (δs). Further, a design-of-experiments study is conducted to relate the energy discharge (Edis) and peak power (Wpeak) to the various governing parameters, as such identifying which parameters maximize energy discharge (Edis) and peak power (Wpeak). The design-of-experiment study reveals that the rectangular fin configuration shows better performance compared to the cylindrical fin configuration.