Vengadesan Elumalai, Senthil Ramalingam
Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur, Chennai, India.
Environ Sci Pollut Res Int. 2022 Sep;29(42):64232-64243. doi: 10.1007/s11356-022-22223-5. Epub 2022 Jul 30.
The thermal performance of a flat plate solar collector (FPSC) is limited minimum due to higher heat loss of the collector and poor heat exchange with the heat transfer fluid. The current study investigates the effect of single-slit twisted tape (TT), double-slit TT, and double-slit straight tape passive-insert devices on enhancing the heat transfer of the FPSC at a constant water flow of 0.025 kg/s. Double-slit inserts have a higher heat transfer area and reduced hydraulic diameter than conventional single-slit TT inserts. The double-slit TT insert creates more fluid mixing and turbulence in the flow than a single-slit TT. The convective heat transfer coefficient for double-slit TT, single-slit TT, and the double-slit straight insert is 47.7%, 26.9%, and 8.7% higher than FPSC with the plain absorber. Double-slit TT inserts are observed with improved energy and exergy efficiency by 23.9% and 46.2% compared to conventional collectors without a flow insert. The average energy efficiency of FPSC without inserts is 48.2%, whereas the double-slit TT is 66.5%. The pressure drop is higher for the collector with inserts than for the collector without inserts, which leads to a little more pump power. Thus, passive inserts help to augment heat transfer in the FPSC.
平板太阳能集热器（FPSC）的热性能因集热器较高的热损失以及与传热流体的不良热交换而受到最低限度的限制。当前的研究调查了单缝扭带（TT）、双缝TT和双缝直带被动插入装置在水流量恒定为0.025 kg/s时对提高FPSC传热的影响。与传统的单缝TT插入件相比，双缝插入件具有更大的传热面积和更小的水力直径。双缝TT插入件在流动中比单缝TT产生更多的流体混合和湍流。双缝TT、单缝TT和双缝直插入件的对流换热系数分别比带有普通吸收器的FPSC高47.7%、26.9%和8.7%。与没有流动插入件的传统集热器相比，观察到双缝TT插入件的能量效率和㶲效率分别提高了23.9%和46.2%。没有插入件的FPSC的平均能量效率为48.2%，而双缝TT为66.5%。带有插入件的集热器的压降比没有插入件的集热器更高，这导致泵功率略高。因此，被动插入件有助于增强FPSC中的传热。
