A High-Performance Heat Exchanger Using Modified Polyvinylidene Fluoride-Based Hollow Fibers

2012 ◽  
Vol 479-481 ◽  
pp. 115-119 ◽  
Author(s):  
Baoan Li ◽  
Han Han Fan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Small Diameter ◽  
Water System ◽  
Hollow Fibers ◽  
Thin Wall ◽  
Temperature Range

Plastic heat exchangers has the shortcomings of bulky, thick pipe wall with large thermal resistance, poor heat transfer, aging of plastic and a narrow temperature range. The key to increase the heat transfer performance of heat exchanger is improving thermal performance of heat conduction.To enhance heat transfer effects and expand the temperature range of using plastic heat exchanger, PVDF with good temperature resistance is used as matrix and modification with graphite fillers to prepare composite hollow fiber which has the advantage of small diameter, thin wall and good thermal conductivity. Also, composite materials hollow fibers are used to prepare shell and tube hollow fiber heat exchanger.The testing of "water - water" system for our heat exchanger module has been done, and the results indicate that adding graphite is helpful to improve thermal conductivity of PVDF-based heat conductive hollow fiber heat exchanger to a certain extent.hen the content of graphite is 3%, the heat transfer effect is the best.

scholarly journals Fouling of Polymeric Hollow Fiber Heat Exchangers by Air Dust

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4931
Author(s):  
Ilya Astrouski ◽  
Miroslav Raudensky ◽  
Tereza Kudelova ◽  
Tereza Kroulikova
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Hollow Fiber ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Hot Water ◽  
Hollow Fibers ◽  
Pressure Drops ◽  
Domestic Appliances

Currently, liquid-to-gas heat exchangers in buildings, domestic appliances and the automotive industry are mainly made of copper and aluminum. Using plastic instead of metal can be very beneficial from an economic and environmental point of view. However, it is required that a successful plastic design meets all the requirements of metal heat exchangers. The polymeric hollow fiber heat exchanger studied in this work is completive to common metal finned heat exchangers. Due to its unique design (the use of thousands of thin-walled microtubes connected in parallel), it achieves a high level of compactness and thermal performance, low pressure drops and high operation pressure. This paper focuses on an important aspect of heat exchanger operation—its fouling in conditions relevant to building and domestic application. In heating, ventilation and air conditioning (HVAC) and automotive and domestic appliances, outdoor and domestic dust are the main source of fouling. In this study, a heat exchanger made of polymeric hollow fibers was tested in conditions typical for indoor HVAC equipment, namely with the 20 °C room air flowing through the hot water coil (water inlet 50 °C) with air velocity of 1.5 m/s. ASHRAE test dust was used as a foulant to model domestic dust. A polymeric heat exchanger with fibers with an outer diameter of 0.6 mm (1960 fibers arranged into 14 layers in total) and a heat transfer area of 0.89 m2 was tested. It was proven that the smooth polypropylene surface of hollow fibers has a favorable antifouling characteristic. Fouling evolution on the metallic heat transfer surfaces of a similar surface density was about twice as quick as on the plastic one. The experimental results on the plastic heat exchanger showed a 38% decrease in the heat transfer rate and a 91% increase in pressure drops after eighteen days of the experiment when a total of 4000 g/m2 of the test dust had been injected into the air duct. The decrease in the heat transfer rate of the heat exchanger was influenced mainly by clogging in the frontal area because the first layers were fouled significantly more than the deeper layers.

scholarly journals Comparison of a Novel Polymeric Hollow Fiber Heat Exchanger and a Commercially Available Metal Automotive Radiator

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1175
Author(s):  
Tereza Kroulíková ◽  
Tereza Kůdelová ◽  
Erik Bartuli ◽  
Jan Vančura ◽  
Ilya Astrouski
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Hollow Fiber ◽  
Pressure Loss ◽  
Air Flow ◽  
Performance Parameters ◽  
University Of Technology ◽  
Flat Tubes ◽  
And Performance ◽  
Louvered Fins

A novel heat exchanger for automotive applications developed by the Heat Transfer and Fluid Flow Laboratory at the Brno University of Technology, Czech Republic, is compared with a conventional commercially available metal radiator. The heat transfer surface of this heat exchanger is composed of polymeric hollow fibers made from polyamide 612 by DuPont (Zytel LC6159). The cross-section of the polymeric radiator is identical to the aluminum radiator (louvered fins on flat tubes) in a Skoda Octavia and measures 720 × 480 mm. The goal of the study is to compare the functionality and performance parameters of both radiators based on the results of tests in a calibrated air wind tunnel. During testing, both heat exchangers were tested in conventional conditions used for car radiators with different air flow and coolant (50% ethylene glycol) rates. The polymeric hollow fiber heat exchanger demonstrated about 20% higher thermal performance for the same air flow. The efficiency of the polymeric radiator was in the range 80–93% and the efficiency of the aluminum radiator was in the range 64–84%. The polymeric radiator is 30% lighter than its conventional metal competitor. Both tested radiators had very similar pressure loss on the liquid side, but the polymeric radiator featured higher air pressure loss.

Heat‐transfer characteristics of polymer hollow fiber heat exchanger for vaporization application

AIChE Journal ◽  
2017 ◽  
Vol 64 (5) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jun Liu ◽  
Hong Guo ◽  
Xingxing Zhi ◽  
Lei Han ◽  
Kai Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Hollow Fiber ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Binary Particle Mixtures as a Heat Transfer Media in Shell-and-Plate Moving Packed Bed Heat Exchangers

2021 ◽  
Author(s):  
Chase Ellsworth Christen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Packed Bed ◽  
Particle Sizes ◽  
Overall Heat Transfer Coefficient ◽  
Solid Media

Solid particles are being considered in several high temperature thermal energy storage systems and as heat transfer media in concentrated solar power (CSP) plants. The downside of such an approach is the low overall heat transfer coefficients in shell-and-plate moving packed bed heat exchangers caused by the inherently low packed bed thermal conductivity values of the low-cost solid media. Choosing the right particle size distribution of currently available solid media can make a substantial difference in packed bed thermal conductivity, and thus, a substantial difference in the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers. Current research exclusively focuses on continuous unimodal distributions of alumina particles. The drawback of this approach is that larger particle sizes require wider particle channels to meet flowability requirements. As a result, only small particle sizes with low packed bed thermal conductivities have been considered for the use in the falling-particle Gen3 CSP concepts. Here, binary particle mixtures, which are defined in this thesis as a mixture of two continuous unimodal particle distributions leading to a continuous bimodal particle distribution, are considered to increase packed bed thermal conductivity, decrease packed bed porosity, and improve moving packed bed heat exchanger performance. This is the first study related to CSP solid particle heat transfer that has considered the packed bed thermal conductivity and moving packed bed heat exchanger performance of bimodal particle size distributions at room and elevated temperatures. Considering binary particle mixtures that meet particle sifting segregation criteria, the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers can be increased by 23% when compared to a monodisperse particle system. This work demonstrates that binary particle mixtures should be seriously considered to improve shell-and-plate moving packed bed heat exchangers.

Experimental Investigation of Heat Transfer Enhancement of Shell and Tube Heat Exchanger Using SnO2-Water and Ag-Water Nanofluids

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
S. V. Sridhar ◽  
R. Karuppasamy ◽  
G. D. Sivakumar
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Convective Heat Transfer Coefficient ◽  
Two Phase ◽  
Tube Heat Exchanger ◽  
Shell And Tube

Abstract In this investigation, the performance of the shell and tube heat exchanger operated with tin nanoparticles-water (SnO2-W) and silver nanoparticles-water (Ag-W) nanofluids was experimentally analyzed. SnO2-W and Ag-W nanofluids were prepared without any surface medication of nanoparticles. The effects of volume concentrations of nanoparticles on thermal conductivity, viscosity, heat transfer coefficient, fiction factor, Nusselt number, and pressure drop were analyzed. The results showed that thermal conductivity of nanofluids increased by 29% and 39% while adding 0.1 wt% of SnO2 and Ag nanoparticles, respectively, due to the unique intrinsic property of the nanoparticles. Further, the convective heat transfer coefficient was enhanced because of improvement of thermal conductivity of the two phase mixture and friction factor increased due to the increases of viscosity and density of nanofluids. Moreover, Ag nanofluid showed superior pressure drop compared to SnO2 nanofluid owing to the improvement of thermophysical properties of nanofluid.

A Tiny Detector Made of a Self-Heated Thermistor for Determining Thermal Conductivity of Biomaterials in Temperature Range 233~313K

2002 ◽  
Author(s):  
H. F. Zhang ◽  
S. X. Cheng ◽  
L. Q. He ◽  
A. L. Zhang ◽  
Y. Zheng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carotid Artery ◽  
Temperature Rise ◽  
Measurement Errors ◽  
Homogeneous Medium ◽  
Standard Samples ◽  
Temperature Range ◽  
A New Technique ◽  
Maximum Measurement

In this paper, a new technique, using a tiny thermistor with 0.3~0.5mm in diameter to determine thermal conductivity of biomaterials in wide temperature range, has been developed. Based on steady spherical heat transfer in an infinite homogeneous medium, thermal conductivity of the measured medium can be determined by power applied and temperature rise of the thermistor. Compared with recommended values, maximum measurement errors of standard samples, aqueous glycol and CaCl2 solutions, water and ice, are 5.1% in temperature range 233~313K. The thermal conductivities of rabbit’s liver, kidney, heart and carotid artery in temperature range 233~293K are determined. Error caused by measurement parameters, effects of the finite scale of the measured medium and the decoupler between the thermistor and the medium are analyzed.

Passive Thermal Management of Excess Heat from Electronic Devices

1989 ◽  
Vol 154 ◽  
Author(s):  
John J. Glatz ◽  
Juan F. Leon
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Thermal Management ◽  
Electronic Devices ◽  
High Thermal Conductivity ◽  
Enabling Technology ◽  
Electronic Components ◽  
Potential Applications ◽  
General Scope

AbstractThermal management in the packaging of electronic components is fast becoming an enabling technology in the development of reliable electronics for a range of applications. The objective of the paper is to assess the feasibility of using advance high thermal conductivity pitch fiber (HTCPF) as a solution to some of the packaging problems. The general scope will include the following: identification of the candidate material and its potential applications; thermal management of the chip to board interface; thermal management of the heat within the multi-layer interconnect board (MIB); thermal management of the standard electronic module-format E (SEME); and heat transfer thru the enclosure to a remote heatsink/heat exchanger.

scholarly journals Performance Analysis of Shell and Tube Type Heat Exchanger Using Aluminium Oxide (Al2O3) Nano-Particle

2021 ◽  
Vol 9 (9) ◽  
pp. 157-164
Author(s):  
Paritosh Singh
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Solid Particles ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube ◽  
Evacuated Tube

Abstract: Research in convective heat transfer using suspensions of nanometer sized solid particles in a base fluid started only over the past decade. Recent investigations on nanofluids, as such suspensions are often called, indicate that the suspended nanoparticles markedly change the transport properties and heat transfer characteristics of the suspension. The very first part of the research work summarizes about the various thermo physical properties of Al2O3 Nanofluid. In evacuated tube solar water heating system nanofluids are used as primary fluid and DM water as secondary fluid in Shell and Tube Heat Exchanger. The experimental analysis of Shell and Tube heat exchanger integrated with Evacuated tube solar collector have been carried out with two types of primary fluids. Research study of shell and tube heat exchanger is focused on heat transfer enhancement by usage of nano fluids. Conventional heat transfer fluids have inherently low thermal conductivity that greatly limits the heat exchange efficiency. The result of analysis shows that average relative variation in LMTD and overall heat transfer coefficient is 24.56% and 52.0% respectively. The payback period of system is reduced by 0.4 years due to saving is in replacement cost of Evacuated Tube Collector. Keywords: ETC; Nanofluid; LMTD; Thermal Conductivity; Overall heat transfer coefficient

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

2019 ◽  
Vol 8 (4) ◽  
pp. 4829-4833
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Dairy Products ◽  
Water System ◽  
Fouling Resistance ◽  
Enhancement Of Heat Transfer ◽  
Technical Performance ◽  
Plate Type ◽  
Milk And Dairy Products ◽  
Fouling Characteristics

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

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