scholarly journals Dehumidification Effect of Polymeric Superabsorbent SAP-LiCl Composite Desiccant-Coated Heat Exchanger with Different Cyclic Switching Time

2020 ◽  
Vol 12 (22) ◽  
pp. 9673
Author(s):  
Bivas Panigrahi ◽  
Yu Sheng Chen ◽  
Win Jet Luo ◽  
Hung Wei Wang
Keyword(s):  
Heat Exchanger ◽  
Switching Time ◽  
Water Vapor Sorption ◽  
Operating Conditions ◽  
Composite Polymer ◽  
Weight Percentage ◽  
Tube Heat Exchanger ◽  
Time Period ◽  
Fin Tube ◽  
Hygroscopic Salts

This study investigated a composite polymer desiccant material’s performance, which is prepared by impregnating solid desiccant such as sodium polyacrylate (SAP) on to hygroscopic salts such as lithium chloride (LiCl). Dehumidification performance of the proposed composite polymer desiccant (SAP-LiCl) was analyzed by coating the suitable weight percentage (wt %) of the desiccant onto a single fin-tube heat exchanger (FTHE) system and testing the desiccant-coated heat exchanger (DCHE) in a testing tunnel under various operating conditions. Net dehumidification efficacy of DCHE in terms of sorption and desorption amount and thermal performance (COPth) were analyzed. For instance, with processed air inflow temperature, relative humidity and regeneration temperature setting of 30 °C, 80% RH and 70 °C, DCHE’s sorption, desorption amount and COPth were recorded as high as 945.1 g, 1115.1 g, and 0.39, respectively. It was further realized that the performance of the DCHE could be enhanced by modulating the cyclic switching time for dehumidification and regeneration processes. For instance, with the aforementioned processed airflow conditions, when the cyclic switching time tuned as 60 min instead of 10 min for a total time period of 120 min, there is a net 58% improvement to the COPth of the system. It was further observed that, under the same time period corresponding to the increase in cyclic switching time, the overall COPth can be enhanced; however, the water vapor sorption and desorption amounts of desiccant were decreased.

Correlations of Fin-Tube Heat Exchanger Performance Data Using Genetic Algorithms, Simulated Annealing and Interval Methods

2001 ◽  
Author(s):  
Arturo Pacheco-Vega ◽  
Mihir Sen ◽  
K. T. Yang ◽  
Rodney L. McClain
Keyword(s):  
Heat Exchanger ◽  
Heat Rate ◽  
Optimization Techniques ◽  
Operating Conditions ◽  
Interval Methods ◽  
Transfer Rates ◽  
Tube Heat Exchanger ◽  
Advantages And Disadvantages ◽  
Mass Flow Rates ◽  
Fin Tube

Abstract We consider the prediction of the performance of an air-water fin-tube compact heat exchanger using correlations of the power-law type. Measurements of the in-tube and over-tube mass flow rates, inlet temperatures and heat transfer rates, with water as the in-tube fluid and air as the over-tube fluid, are used to show that a regression analysis for the best-fit correlation of a prescribed form does not provide a unique answer in the heat rate predictions and that a global, rather than a local, search for the best correlation should be conducted. To this end, we propose the application of three different global optimization techniques to find the constants in a prescribed correlating function which can then be used to predict the performance of this heat exchanger under different operating conditions. Comparisons of the different results are then made to determine the relative advantages and disadvantages among the methods in terms of efficiency, accuracy and certainty of the results. Every method is found to have advantages over the others, and the results demonstrate that all three techniques are able to predict well the performance of this heat exchanger.

Heat transfer enhancement for fin-tube heat exchanger using vortex generators

2002 ◽  
Vol 16 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Seong-Yeon Yoo ◽  
Dong-Seong Park ◽  
Min-Ho Chung ◽  
Sang-Yun Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Vortex Generators ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Fin Tube

CFD analysis of fin tube heat exchanger with a pair of delta winglet vortex generators

2012 ◽  
Vol 26 (9) ◽  
pp. 2949-2958 ◽  
Author(s):  
Seong Won Hwang ◽  
Dong Hwan Kim ◽  
June Kee Min ◽  
Ji Hwan Jeong
Keyword(s):  
Heat Exchanger ◽  
Vortex Generators ◽  
Cfd Analysis ◽  
Tube Heat Exchanger ◽  
Delta Winglet ◽  
Fin Tube

scholarly journals Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

2021 ◽  
Vol 11 (19) ◽  
pp. 9261
Author(s):  
Yun-Seok Choi ◽  
Youn-Jea Kim
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Magnetic Fields ◽  
Heat Transfer Performance ◽  
Permanent Magnets ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
Improve Heat Transfer ◽  
Fin Tube

As electrical devices become smaller, it is essential to maintain operating temperature for safety and durability. Therefore, there are efforts to improve heat transfer performance under various conditions, such as using extended surfaces and nanofluids. Among them, cooling methods using ferrofluid are drawing the attention of many researchers. This fluid can control the movement of the fluid in magnetic fields. In this study, the heat transfer performance of a fin-tube heat exchanger, using ferrofluid as a coolant, was analyzed when external magnetic fields were applied. Permanent magnets were placed outside the heat exchanger. When the magnetic fields were applied, a change in the thermal boundary layer was observed. It also formed vortexes, which affected the formation of flow patterns. The vortex causes energy exchanges in the flow field, activating thermal diffusion and improving heat transfer. A numerical analysis was used to observe the cooling performance of heat exchangers, as the strength and number of the external magnetic fields were varying. VGs (vortex generators) were also installed to create vortex fields. A convective heat transfer coefficient was calculated to determine the heat transfer rate. In addition, the comparative analysis was performed with graphical results using contours of temperature and velocity.

scholarly journals Numerical Analysis on Natural Convection Heat Transfer in a Single Circular Fin-Tube Heat Exchanger (Part 1): Numerical Method

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 363 ◽  
Author(s):  
Jong Hwi Lee ◽  
Jong-Hyeon Shin ◽  
Se-Myong Chang ◽  
Taegee Min
Keyword(s):  
Natural Convection ◽  
Heat Exchanger ◽  
Rayleigh Number ◽  
Numerical Method ◽  
Stokes Equations ◽  
Convection Heat Transfer ◽  
Boussinesq Approximation ◽  
Tube Heat Exchanger ◽  
Fin Tube ◽  
Rayleigh Numbers

In this research, unsteady three-dimensional incompressible Navier–Stokes equations are solved to simulate experiments with the Boussinesq approximation and validate the proposed numerical model for the design of a circular fin-tube heat exchanger. Unsteady time marching is proposed for a time sweeping analysis of various Rayleigh numbers. The accuracy of the natural convection data of a single horizontal circular tube with the proposed numerical method can be guaranteed when the Rayleigh number based on the tube diameter exceeds 400, which is regarded as the limitation of numerical errors due to instability. Moreover, the effective limit for a circular fin-tube heat exchanger is reached when the Rayleigh number based on the fin gap size ( Ra s ) is equal to or exceeds 100. This is because at low Rayleigh numbers, the air gap between the fins is isolated and rarely affected by natural convection of the outer air, where the fluid provides heat resistance. Thus, the fin acts favorably when Ra s exceeds 100.

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