The Effect of Electric Load Profiles on the Performance of Off-Grid Residential Hybrid Renewable Energy Systems
The Effect of Electric Load Profiles on the Performance of Off-Grid Residential Hybrid Renewable Energy Systems
复制标题
电力负荷曲线对离网住宅混合可再生能源系统性能的影响
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
S. Treado
中科院分区：
文献类型：
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作者：
S. Treado
本文研究了离网住宅混合可再生电力系统的能源性能，特别是电力负荷曲线对收集可用太阳能和避免消耗丙烷形式的辅助能源的能力的影响。这些概念说明了电力和丙烷燃烧的冰箱的能源性能的分析。离网电力系统通常包含可再生能源，例如风能或太阳能光伏（PV），并由丙烷燃料电动机/发电机提供备用电力。在其他设计决策中，住宅消费者面临的选择是采用具有传统蒸汽压缩制冷系统的电冰箱，还是作为吸收式制冷系统操作的燃料燃烧冰箱。一个有趣的问题是，从能量的角度来看，使用电力来运行冰箱是否更有利，这可能由PV和丙烷电动机/发电机的某种组合提供，从而利用相对较高的电冰箱性能系数（COP）和自由太阳能，但必须接受电动机/发电机的低电转换效率，或者使用来自丙烷燃烧的热能来通过吸收系统产生制冷效果，尽管具有低得多的COP。该分析由于以下事实而变得复杂：大多数离网可再生电力系统利用电池组来在不能从风力涡轮机或PV系统获得电力时提供电力，因此电池组的充电状态将对在任何时刻可用的能源具有显著影响。每日电力负荷曲线与可变太阳能输入相结合，决定了电池组的充电状态，两者之间的同步程度是决定性能的关键因素。年能量使用和燃料输入强烈地取决于在真实的时间内利用可再生能源以避免电池组转换损失和过量电力的倾倒的能力，以及具有足够的电池存储容量以最小化对电动机/发电机的操作的需要以满足在可再生能源不可用期间发生的电负载的能力。
This paper investigates the energy performance of off-grid residential hybrid renewable electric power systems, particularly the effect of electric load profiles on the ability to harvest available solar energy and avoid the consumption of auxiliary energy in the form of propane. The concepts are illustrated by an analysis of the energy performance of electric and propane-fired refrigerators. Off-grid electric power systems frequently incorporate a renewable source, such as wind or solar photovoltaic (PV), with a back-up power provided by a propane fueled motor/generator. Among other design decisions, residential consumers face the choice of employing an electric refrigerator with a conventional vapor compression refrigeration system, or a fuel-fired refrigerator operating as an absorption refrigeration system. One interesting question is whether it is more advantageous from an energy perspective to use electricity to run the refrigerator, which might be provided by some combination of the PV and propane motor/generator, thereby taking advantage of the relatively higher electric refrigerator Coefficient of Performance (COP) and free solar energy but having to accept a low electrical conversion efficiency of the motor/generator, or use thermal energy from the combustion of propane to produce the refrigeration effect via an absorption system, albeit with a much lower COP. The analysis is complicated by the fact that most off-grid renewable electrical power systems utilize a battery bank to provide electrical power when it is not available from the wind turbine or PV system, so the state of charge of the battery bank will have a noticeable impact on what energy source is available at any moment in time. Daily electric load profiles combined with variable solar energy input determine the state of charge of the battery bank, with the degree of synchronization between the two being a critical factor in determining performance. The annual energy usage and fuel input depend strongly on the ability to make use of the renewable sources in real time to avoid battery bank conversion losses and dumping of excess electrical power, as well as to have sufficient battery storage capacity to minimize the need for operation of the motor/generator to meet electric loads which occur during periods when the renewable energy is not available.