Thermal performance predictions and tests of a novel type of flat plate solar thermal collectors by integrating with a freeze tolerance solution
Thermal performance predictions and tests of a novel type of flat plate solar thermal collectors by integrating with a freeze tolerance solution
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DOI：
10.1016/j.enconman.2019.111784
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发表时间：
2019-10
影响因子：
10.4
通讯作者：
Jie Deng;T. O'Donovan;Z. Tian;J. King;Stuart Speake
中科院分区：
文献类型：
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作者：
Jie Deng;T. O'Donovan;Z. Tian;J. King;Stuart Speake
平板太阳能集热器（FPSC）的一种新的设计概念是通过使用柔性硅胶管与耐冷冻（所谓的“冰免疫”）解决方案相结合来构思和开发的。其目的是在具有FPSC的太阳能热系统中直接运行水，而不是使用昂贵的防冻液，并去除二次传热设施（例如带有埋地换热器的额外水箱）。这种太阳能集热器的成功开发将使传统太阳能热系统的安装成本降低，而无需二次传热设施。在前期设计中，基于集热器集总热容模型和CFD（Computational Fluid Dynamics）计算，对蛇形管和集管两种结构的FPSC的热力性能进行了预测。然后制作了两个具有防冰硅胶管的FPSC原型（一个AES蛇形管类型，一个改进的中国微热管阵列面板）以确定集热器性能，并通过实验测试与原始AES太阳能keymark参考面板进行比较。结果表明，国产微热管阵列板的单位面积集热器流量性能优于AES集热器立管太阳能keymark板，而带硅胶管的AES蛇形管板在Tm ≤ 0.035时性能略低于太阳能keymark板，在Tm> 0.035时性能优于太阳能keymark板。蛇形管板和中国微热管阵列板都集成了硅胶管的冻结耐受性被证明是有效的，因为修改没有显着损害集热器的热性能。
A novel design concept of Flat Plate Solar Collectors (FPSCs) is conceived and developed by integrating with a freeze-tolerant (so-called ‘ice immune’) solution using flexible silicone tubing. It is intended to directly run water in the solar thermal systems with the FPSCs instead of using expensive anti-freeze fluids, and to remove secondary heat transfer facilities (eg an extra tank with a buried heat exchanger). Successful development of such kind of solar thermal collectors will enable a reduction of installed cost of conventional solar thermal systems without needing secondary heat transfer facilities. In the prophase design, thermal performances of FPSCs with two configurations, ie the serpentine tube type and the header riser type, were predicted based on the collector lumped thermal capacitance model alongside CFD (Computational Fluid Dynamics) calculations. Then two prototypes of FPSCs with the ice-immune silicone tubing (one AES serpentine tube type, one modified Chinese micro-heat-pipe-array panel) were made to determine the collector performance and compared to an original AES solar keymark reference panel via experimental tests. The results show that the Chinese micro-heat-pipe-array panel performs better than the AES header riser solar keymark panel in terms of flow rate per m 2 collector aperture area, while the AES serpentine tube panel with silicone tubing performs somewhat lower than the solar keymark with T m∗≤ 0.035 and better than the solar keymark when T m∗> 0.035. The serpentine tube panel and the Chinese micro-heat-pipe-array panel both integrated with silicone tubing for freeze tolerance are proven to be effective as the modification doesn’t compromise the collector thermal performance markedly.