Organic rankine cycle with positive displacement expander and variable working fluid composition
Organic rankine cycle with positive displacement expander and variable working fluid composition
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发表时间：
2016-07
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通讯作者：
P. Collings;Zhibin Yu
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作者：
P. Collings;Zhibin Yu
有机朗肯循环常用于低温热源的开发。这些项目的温差相对较小，因此特别容易受到环境条件变化的影响，特别是在使用空冷冷凝器的情况下。作者最近证明，具有可变工作流体成分的动态ORC，经调整以使冷凝温度与散热器匹配，可用于在此类条件下实现全年发电量的显著增加[1]。然而，这假设膨胀机是一个涡轮机，能够在多个压力比下运行，用于大规模应用。本文将研究使用具有固定膨胀比的正位移膨胀机的小规模ORC系统是否也可以从这种新概念中受益。本文首先建立了一个数值模型。然后对一个案例进行了综合分析。结果表明，动态有机朗肯循环概念可以应用于使用具有固定膨胀比的正排量膨胀机的低功率应用，并且仍然可以改善全年的发电量。
Organic Rankine Cycles are often used in the exploitation of low-temperature heat sources. The relatively small temperature differential available to these projects makes them particularly vulnerable to changing ambient conditions, especially if an air-cooled condenser is used. The authors have recently demonstrated that a dynamic ORC with a variable working fluid composition, tuned to match the condensing temperature with the heat sink, can be used to achieve a considerable increase in year-round power generation under such conditions [1]. However, this assumed the expander was a turbine capable of operating at multiple pressure ratios for large scale applications. This paper will investigate if small scale ORC systems that use positive-displacement expanders with fixed expansion ratios could also benefit from this new concept. In this paper, a numerical model was firstly developed. A comprehensive analysis was then conducted for a case study. The results showed that the dynamic Organic Rankine Cycle concept can be applied to lower-power applications that use that use positive-displacement expanders with fixed expansion ratios and still result in improvements in year-round energy generation.