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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机译：由于相变中包含大量的能量（从蒸汽到液体），可以非常有利地使用传热过程中的冷凝。该贡献集中于在空调中使用聚合物中空纤维热交换器（PHFHE）。 PHFHE由数百或数千个聚合物中空纤维组成，其外径约为1毫米。壁厚约为外径的10％。 PHFHE是一种热交换器，具有重量轻，易于成型，耐腐蚀和耐多种化学溶液的优点。与金属热交换器（由铜，铝或不锈钢制成）相比，PHFHE的塑料壁导热系数低（介于0.1和0.4 Wm-1K-1之间）。这似乎是他们的主要缺点。但是，由于纤维壁的厚度极小，因此这一缺点可以忽略不计。 PHFHE是紧凑型热交换器，相对于其体积而言，其传热面积大。本文显示了对PHFHE进行缩合测试的结果，该PHFHE由6个当量的190毫米聚丙烯纤维等效层组成。纤维总数为798。空气湿度设置为50％，空气温度为27°C，这是空调技术中此类测试的典型条件。另一个重要参数是空气的速度。测试速度选择为3 m s〜（-1）和1 m s〜（-1）。通过将PHFHE放在三个不同的位置来研究重力的影响。将纤维放置在水平和垂直位置，以及纤维与地面成45°角的位置。该研究表明将PHFHE放置在水平位置是无效的，并建议最好在纤维层之间设置较大的距离。
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