Polymeric Hollow-Fiber Heat Exchangers for Thermal Desalination Processes

2010 ◽  
Vol 49 (23) ◽  
pp. 11961-11977 ◽  
Author(s):  
Liming Song ◽  
Baoan Li ◽  
Dimitrios Zarkadas ◽  
Saskia Christian ◽  
Kamalesh K. Sirkar
Keyword(s):  
Hollow Fiber ◽  
Heat Exchangers ◽  
Thermal Desalination

Polymeric hollow fiber heat exchangers

2019 ◽  
Author(s):  
Miroslav Raudenský
Keyword(s):  
Hollow Fiber ◽  
Heat Exchangers

Polymeric Hollow-Fiber Bundles as Immersed Heat Exchangers

2018 ◽  
Vol 41 (7) ◽  
pp. 1457-1465 ◽  
Author(s):  
Klarissa Weiß ◽  
Ilya Astrouski ◽  
Marcus Reppich ◽  
Miroslav Raudenský
Keyword(s):  
Hollow Fiber ◽  
Heat Exchangers ◽  
Fiber Bundles

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

2005 ◽  
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.

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

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.

scholarly journals PRESSURE DROP STUDY OF POLYMERIC HOLLOW FIBER HEAT EXCHANGERS

2020 ◽  
Author(s):  
T. Kroulíková ◽  
I. Astrouski ◽  
T. Kůdelová
Keyword(s):  
Pressure Drop ◽  
Hollow Fiber ◽  
Heat Exchangers

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.

Thermal-hydraulic characteristics of gasketed plate heat exchangers as a preheater for thermal desalination systems

2020 ◽  
Vol 205 ◽  
pp. 112425 ◽  
Author(s):  
Muhammad Ahmad Jamil ◽  
Zia Ud Din ◽  
Talha S. Goraya ◽  
Haseeb Yaqoob ◽  
Syed M. Zubair
Keyword(s):  
Heat Exchangers ◽  
Hydraulic Characteristics ◽  
Plate Heat ◽  
Thermal Desalination
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