Polymeric Hollow-Fiber Bundles as Immersed Heat Exchangers

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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Polymeric Hollow-Fiber Heat Exchangers for Thermal Desalination Processes

Industrial & Engineering Chemistry Research ◽

10.1021/ie100375b ◽

2010 ◽

Vol 49 (23) ◽

pp. 11961-11977 ◽

Cited By ~ 27

Author(s):

Liming Song ◽

Baoan Li ◽

Dimitrios Zarkadas ◽

Saskia Christian ◽

Kamalesh K. Sirkar

Keyword(s):

Hollow Fiber ◽

Heat Exchangers ◽

Thermal Desalination

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Influence of Condensation on the Outer Surface of Polymer Hollow Fiber Heat Exchangers During Heat Transfer

ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2018-7728 ◽

2018 ◽

Author(s):

Tereza Brozova ◽

Erik Bartuli

Keyword(s):

Heat Transfer ◽

Hollow Fiber ◽

Heat Exchangers ◽

Air Conditioning ◽

Outer Diameter ◽

Compact Heat Exchangers ◽

Low Weight ◽

Large Heat ◽

Chemical Solutions ◽

Copper Aluminum

Condensation during heat transfer processes can be very beneficially used due to the large amount of energy contained in phase change (vapor to liquid). This contribution focuses on the possible use of polymer hollow fiber heat exchangers (PHFHEs) in air conditioning. PHFHEs consist of hundreds or thousands of polymer hollow fibers with an outer diameter of around 1 mm. The wall thickness is approximately 10% of the outer diameter. PHFHEs are heat exchangers with such benefits as low weight, easy shaping, corrosion resistance, and resistance to many chemical solutions. In comparison with metal heat exchangers (made of copper, aluminum, or stainless steel) the plastic wall of PHFHEs has low thermal conductivity (between 0.1 and 0.4 Wm-1K-1). This seems to be their key disadvantage. However, due to the extremely small thickness of the fiber’s wall this disadvantage is negligible. PHFHEs are compact heat exchangers with a large heat transfer area with respect to their volume. This paper shows the results of condensation tests for PHFHEs that consist of 6 equivalent layers of polypropylene fibers with a length of 190 mm. The total number of fibers is 798. The air humidity was set to 50% with an air temperature of 27°C, which are the typical conditions for such tests in air conditioning technology. Another important parameter was the velocity of the air. Testing velocities were chosen as 3 m s−1 and 1 m s−1. The influence of gravity was studied by putting the PHFHEs in three different positions. The fibers were placed in horizontal and vertical positions, and in a position where fibers form an angle of 45° with the ground. The study showed the ineffectiveness of placing the PHFHE in a horizontal position and suggests that it is better to have a larger distance between the layers of fibers.

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Letter to the Editor on: “Darcy permeability of hollow fiber bundles used in blood oxygenation devices” [J. Membr. Sci. 382 (2011) 238-242]

Journal of Membrane Science ◽

10.1016/j.memsci.2015.09.012 ◽

2015 ◽

Vol 496 ◽

pp. 359-360

Author(s):

Shalv Madhani ◽

William J. Federspiel

Keyword(s):

Hollow Fiber ◽

Blood Oxygenation ◽

Fiber Bundles ◽

Letter To The Editor

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Darcy permeability of hollow fiber bundles used in blood oxygenation devices

Journal of Membrane Science ◽

10.1016/j.memsci.2011.08.012 ◽

2011 ◽

Vol 382 (1-2) ◽

pp. 238-242 ◽

Cited By ~ 20

Author(s):

Heather E. Pacella ◽

Heidi J. Eash ◽

Brian J. Frankowski ◽

William J. Federspiel

Keyword(s):

Hollow Fiber ◽

Blood Oxygenation ◽

Fiber Bundles

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PRESSURE DROP STUDY OF POLYMERIC HOLLOW FIBER HEAT EXCHANGERS

Engineering Mechanics 2020 ◽

10.21495/5896-3-314 ◽

2020 ◽

Author(s):

T. Kroulíková ◽

I. Astrouski ◽

T. Kůdelová

Keyword(s):

Pressure Drop ◽

Hollow Fiber ◽

Heat Exchangers

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