The influence of hollow fibers orientation inside the polymeric hollow fiber heat exchanger on the heat transfer intensity

2012 ◽

Vol 479-481 ◽

pp. 115-119 ◽

Cited By ~ 1

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.

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Fouling of Polymeric Hollow Fiber Heat Exchangers by Air Dust

Materials ◽

10.3390/ma13214931 ◽

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.

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

Polymers ◽

10.3390/polym13071175 ◽

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.

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

AIChE Journal ◽

10.1002/aic.16049 ◽

2017 ◽

Vol 64 (5) ◽

pp. 1783-1792 ◽

Cited By ~ 1

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

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Polymeric Hollow Fiber Heat Exchangers (PHFHEs): A New Type of Compact Heat Exchanger for Lower Temperature Applications

Heat Transfer: Volume 4 ◽

10.1115/ht2005-72590 ◽

2005 ◽

Cited By ~ 3

Author(s):

Dimitrios M. Zarkadas ◽

Baoan Li ◽

Kamalesh K. Sirkar

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Thermal Performance ◽

Hollow Fiber ◽

Heat Exchangers ◽

Operating Cost ◽

Polymer Materials ◽

Steam Condensation ◽

New Type ◽

Shell And Tube

Plastic heat exchangers are characterized by an inferior thermal performance compared to their metal counterparts. Therefore, their usage is mainly limited to handling corrosive media or when ultra high purity is required, e.g., pharmaceutical industry. Polymeric Hollow Fiber Heat Exchangers (PHFHEs) have recently been proposed [1] as a new type of heat exchanger that can overcome these constraints and offer the same or better thermal performance than metallic shell and tube or plate heat exchangers while occupying a much smaller volume. In this paper we report our results for heat transfer in PHFHEs with both parallel and cross flow in the shell side of the device. Fibers made of polypropylene (PP) and polyetheretherketone (PEEK) were tested. In addition, steam condensation studies in PHFHEs are reported for the first time. The overall heat transfer coefficients achieved for water-water and water-brine systems are as high as 1400 Wm−2K−1. These values are higher than any value reported for plastic heat exchangers and comparable with commonly acceptable design values for metal shell and tube heat exchangers. Similar coefficients were obtained for steam condensation. Polymeric hollow fiber heat exchangers can also achieve high thermal effectiveness, large number of transfer units (NTU) and very small height of a transfer unit (HTU), if properly rated. If designed like commercial membrane contactors, they can achieve up to 12 transfer units in a single device, not longer than 60–70 cm! In addition, the conductance per unit volume PHFHEs achieved was up to one order of magnitude higher compared to metal heat transfer equipment. This superior thermal performance is also accompanied by considerably lower pressure drops. Therefore, the operation of PHFHEs will be characterized by a low operating cost. Combined with the much lower cost, lower weight and elimination of metal contamination polymer materials offer, it is obvious that PHFHEs constitute a potential substitute for metal heat exchangers on both thermal performance and economical grounds. Possible application fields include the food, pharmaceutical and biomedical industries as well as applications where corrosion resistant, light and very efficient devices are required, i.e., desalination, solar and offshore heat transfer applications.

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