Method for Optimizing the Field Coils of Internally Illuminated Photobioreactors
Method for Optimizing the Field Coils of Internally Illuminated Photobioreactors
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DOI：
10.1109/tmag.2014.2320934
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发表时间：
2014-11-01
影响因子：
2.1
通讯作者：
Buchholz, Rainer
中科院分区：
文献类型：
--
作者：
Sutor, Alexander;Heining, Martin;Buchholz, Rainer
提出了一种新型光生物反应器（PBR）场线圈的优化设计方法。在这些PBRs中，生长有光合活性的微生物或细胞。一个新的概念，为照明的PBRs是必要的，因为这些反应堆的外部照明导致有限的穿透深度的光。我们提出的解决方案是通过无线光发射器（WLE）进行内部照明。这增加了光合活性微生物或细胞的可管理的培养体积。照明系统基于浮动光发射器，其通过近场谐振电感耦合无线供电。浮动光发射器能够比外部照明系统更均匀地照明PBR。我们设计了磁场线圈，在反应堆内部产生中频电磁场。我们选择磁通量密度B = 0.95 mT和频率f = 178 kHz。为了达到最佳效率，磁场必须尽可能均匀。我们演示了如何使用差分进化方法进行这种优化。使用优化的励磁线圈设计，最小磁场增加了近10%，保持安培匝数不变。两种反应器类型的横截面上的光分布的比较清楚地表明，通过WLE的内部照明导致反应器中更均匀的光分布和更高的平均光强度。通过比较施加磁场和不施加磁场时的生长速率、细胞干重和最大光合产量，可以排除磁场对绿色莱茵衣藻的影响。此外，可以排除由于悬置的WLE而可能发生的机械应力的负面影响。以125 WLE/L机械应激的培养物显示出与对照培养物相同的最大生长速率。最后，外部和通过WLE内部照明的PBR的比较显示在指数增长阶段相同的增长率。然而，线性阶段的生长速率是外部照射对照培养物的速率的两倍以上，导致获得的生物量高出80%以上。
We present a method for optimizing the design of field coils for a new type of photobioreactor (PBR). In those PBRs, photosynthetic active microorganisms or cells are grown. A novel concept for the illumination of PBRs was necessary, as the external illumination of those reactors leads to a limited penetration depth of light. The solution we propose is an internal illumination via wireless light emitters (WLEs). This increases the manageable culture volume of photosynthetic active microorganisms or cells. The illumination system is based on floating light emitters, which are powered wirelessly by near field resonant inductive coupling. The floating light emitters are able to illuminate a PBR more homogeneously than external illumination systems. We designed field coils to produce an intermediate frequency electromagnetic field inside the reactor. We chose a magnetic flux density B = 0.95 mT and a frequency f = 178 kHz. To reach optimal efficiency, the magnetic field has to be as homogeneous as possible. We demonstrate how this optimization can be performed with the method of differential evolution. Using the optimized field coil design, the minimum magnetic field was increased by almost 10% keeping the number of ampere-turns constant. A comparison of the light profiles over the cross section of both reactor types show clearly that the internal illumination via WLE results in a more uniform light distribution and a higher average light intensity in the reactor. An impact of the magnetic field on the green alga Chlamydomonas reinhardtii could be excluded by comparing the growth rate, the achieved cell dry weight and the maximum photosynthetic yield with and without applied magnetic field. Furthermore, a negative effect of the potentially occurring mechanical stress due to the suspended WLE can be excluded. A culture which is mechanically stressed by 125 WLE per liter shows the same maximal growth rate as a control culture. Finally, the comparison of an externally and a via WLE internally illuminated PBR shows the same growth rates in the exponential growth phase. However, the growth rate in the linear phase is more than twice the rate of the externally illuminated control culture, resulting in a more than 80% higher achieved biomass.