Abstract Two types of solar air collectors (SACs), namely, a conventional-tube collector (C-TC) and a transparent-tube collector (T-TC), are designed on the basis of flat micro-heat pipe arrays (FMHPA) and are compared. FMHPA is used as the core heat transfer element for both collectors. Absorption coatings are located at different places. It is located at, namely, on the inner wall of vacuum tube and on the FMHPA evaporation section in the C-TC and the T-TC. A large volumetric flow rate of air contributes to high efficiency. Results of the comparative experiment show that even if the thermal efficiency of the C-TC (77.6%) is smaller than that of the T-TC (85.0%), the useful energy of the C-TC (641 W) is larger than that of the T-TC (497 W). Moreover, the COP values of the C-TC and T-TC are 11.4 and 8.9, respectively. The unit initial investments are 0.15 and 0.21 $/W. Hence, considering the heating capability and price advantage, the C-TC is a better collector form than the T-TC in the same collector gross area. The collector pressure drop does not exceed 19.1 Pa. These results can serve as a reference for the selection and design of SACs for heating applications and crop drying.

中文翻译：

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基于扁平微热管阵列（FMHPA）的两种真空管太阳能集热器热性能对比实验研究

摘要 基于扁平微热管阵列（FMHPA）设计了两种类型的太阳能空气集热器（SAC），即传统管式集热器（C-TC）和透明管式集热器（T-TC）。并进行比较。FMHPA 用作两个集热器的核心传热元件。吸收涂层位于不同的地方。它位于，即在C-TC和T-TC的真空管内壁和FMHPA蒸发段上。空气的大体积流量有助于高效率。对比实验结果表明，即使 C-TC 的热效率（77.6%）小于 T-TC（85.0%），C-TC 的有用能量（641 W）也大于T-TC (497 W)。此外，C-TC 和 T-TC 的 COP 值分别为 11.4 和 8.9。单位初始投资为 0.15 美元和 0.21 美元/瓦。因此，考虑到加热能力和价格优势，在相同的集热器总面积下，C-TC 是比 T-TC 更好的集热器形式。集热器压降不超过 19.1 Pa。这些结果可以作为用于加热应用和作物干燥的 SAC 的选择和设计的参考。