收集生物机械能还是携带电池？一种基于代谢功率比较的评估方法。
Harvesting biomechanical energy or carrying batteries? An evaluation method based on a comparison of metabolic power.
作者信息
Schertzer Eliran, Riemer Raziel
机构信息
Department of Industrial Engineering and Management, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva, Israel.
出版信息
J Neuroeng Rehabil. 2015 Mar 20;12:30. doi: 10.1186/s12984-015-0023-7.
BACKGROUND
Harvesting energy from human motion is an innovative alternative to using batteries as a source of electrical power for portable devices. Yet there are no guidelines as to whether energy harvesting should be preferred over batteries. This paper introduces an approach to determine which source of energy should be preferred. The proposed approach compares the metabolic power while harvesting energy and while using batteries (or any other power supply, e.g., solar panels), which provide equal amount of energy. Energy harvesting is preferred over batteries if the metabolic power required to harvest the energy is lower than that required to carry the batteries. Metabolic power can be experimentally measured. However, for design purposes, it is essential to assess differences in metabolic power as a function of the device parameters.
THE MODEL
To this end, based on the proposed approach, we develop a mathematical model that considers the following parameters: the device's mass, its location on the human body, the electrical power output, cost of harvesting (COH), walking time, and the specific energy of the battery.
METHOD
We apply the model in two ways. First, we conduct case studies to examine current ankle, knee, and back energy harvesting devices, and assess the walking times that would make these devices preferable over batteries. Second, we conduct a design scenarios analysis, which examines future device developments.
RESULTS
The case studies reveal that to be preferred over batteries, current harvesting devices located on the ankle, knee, or back would require walking for 227 hours, 98 hours, or 260 hours, respectively. This would replace batteries weighing 6.81 kg (ankle), 5.88 kg (knee), or 2.6 kg (back). The design scenarios analysis suggests that for harvesting devices to be beneficial with less than 25 walking hours, future development should focus on light harvesting devices (less than 0.2 kg) with low COH (equal or lower than 0). Finally, a comparison with portable commercial solar panels reveals that under ideal sun exposure conditions, solar panels outperform the current harvesting devices.
CONCLUSIONS
Our model offers a tool for assessing the performance of energy harvesting devices.
背景
从人体运动中获取能量是一种创新的替代方案，可用于为便携式设备提供电力，而无需使用电池。然而，对于是否应优先选择能量收集而非电池，目前尚无指导方针。本文介绍了一种确定应优先选择哪种能源的方法。所提出的方法比较了在收集能量时以及使用电池（或任何其他电源，例如太阳能电池板）时的代谢功率，前提是两者提供等量的能量。如果收集能量所需的代谢功率低于携带电池所需的代谢功率，则优先选择能量收集。代谢功率可以通过实验测量。然而，出于设计目的，至关重要的是评估作为设备参数函数的代谢功率差异。
模型
为此，基于所提出的方法，我们开发了一个数学模型，该模型考虑以下参数：设备的质量、其在人体上的位置、电力输出、收集成本（COH）、步行时间以及电池的比能量。
方法
我们以两种方式应用该模型。首先，我们进行案例研究，以检查当前的脚踝、膝盖和背部能量收集设备，并评估使这些设备比电池更具优势的步行时间。其次，我们进行设计方案分析，以研究未来的设备发展。
结果
案例研究表明，要比电池更具优势，当前位于脚踝、膝盖或背部的收集设备分别需要步行227小时、98小时或260小时。这将取代重6.81千克（脚踝）、5.88千克（膝盖）或2.6千克（背部）的电池。设计方案分析表明，对于步行时间少于25小时就有益的收集设备，未来的发展应侧重于重量轻（小于0.2千克）且COH低（等于或低于0）的收集设备。最后，与便携式商用太阳能电池板的比较表明，在理想的阳光照射条件下，太阳能电池板的性能优于当前的收集设备。
结论
我们的模型提供了一种评估能量收集设备性能的工具。
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