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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.

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.

Polymeric hollow fibre heat exchangers are the new alternative to common metal heat exchangers. These heat exchangers provide advantages, such as low weight, corrosion resistance, easy shaping and machining. Moreover, they consume less energy during their production. Therefore, they are environmentally friendly. The paper deals with shell & tube heat exchangers, which consist of hundreds of polymeric hollow fibres. The structure of the heat transfer surfaces has a significant influence on the effectivity of the use of the heat transfer area that is formed by the polymeric hollow fibres. The study gives a comparison of heat exchangers with an identical outer volume. The difference between them is in the structure of the heat transfer insert. One of the presented heat exchangers has fibres that are in-line and the second heat exchanger has staggered fibres. The study also pays attention to the difference in differential pressures caused by the difference in the structure of the heat transfer surfaces.

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This article deals with polymer hollow fibre heat exchangers as an alternative to the common metal heat exchangers. These heat exchangers are made of hundreds or even thousands of polymer hollow fibres. The heat exchangers provide such benefits as low weight, corrosion resistance, and easy shaping and machining. Moreover, they are environmentally friendly. These fibres are the key part of such heat exchangers. Therefore, it is necessary to ensure their durability during their lifetime. The paper shows tests the life expectancy of hollow fibres by internal pressure loading. The tests are performed in a water bath at a temperature of 80°C. This simulates the operating conditions of the heat exchangers.

Polymeric hollow fiber heat exchangers are an alternative to common metal heat exchangers in lowtemperature applications. Their advantages are low cost, low weight, and corrosion resistance. The heat transfer surface consists of hundreds or even thousands of fibers of small diameter. The PHFHE for gas-liquid application has a regular structure, which prevents the fibers from blocking the heat transfer surface and allow the gas to flow through the heat exchanger. This arrangement, known as the bank of tubes, is common for the multipass shell and tube heat exchangers. There are relations used to estimate the pressure drop of flow passing the bank of tubes. Those are based on extensive experimental research with steel tubes. Unfortunately, it seems that those relations do not apply to flexible fibers. This paper shows the discrepancy between the theory for non-flexible bank of tubes and measured data of PHFHE.