Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures
Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures
复制标题
DOI：
10.3390/en8032097
复制
发表时间：
2015-03
期刊：
影响因子：
3.2
通讯作者：
F. Heberle;D. Brüggemann
中科院分区：
文献类型：
--
作者：
F. Heberle;D. Brüggemann
提出了一种基于有机朗肯循环（ORC）的地热发电二元电厂的热经济性评价方法。本研究的重点是分析，如果使用非共沸混合物作为工作流体的效率增加过度补偿有关的主要发电厂组件的额外要求。的优化方法相比，纯介质的系统。在工艺模拟的基础上，设计了换热设备，并进行了成本估算。对于100至180 °C之间的热源温度，与纯流体相比，选定的非共沸混合物导致第二定律效率增加高达20.6%。特别是对于约160 °C的温度，与最有效的纯流体相比，丙烷/异丁烷、异丁烷/异戊烷或R227 ea/R245 fa等混合物显示出更低的发电成本。在地热流体温度为120 °C的情况下，R227 ea和丙烷/异丁烷是具有成本效益的工作流体。关于非共沸混合物的流体性质的不确定性，主要影响换热表面。然而，对确定的经济参数的影响是微不足道的。一般而言，非共沸混合物是改善地热ORC系统的经济性的有前途的方法。此外，混合物的使用增加了潜在工作流体的范围，这在考虑氟化制冷剂的当前和未来法律的要求的背景下是重要的。
We present a thermo-economic evaluation of binary power plants based on the Organic Rankine Cycle (ORC) for geothermal power generation. The focus of this study is to analyse if an efficiency increase by using zeotropic mixtures as working fluid overcompensates additional requirements regarding the major power plant components. The optimization approach is compared to systems with pure media. Based on process simulations, heat exchange equipment is designed and cost estimations are performed. For heat source temperatures between 100 and 180 °C selected zeotropic mixtures lead to an increase in second law efficiency of up to 20.6% compared to pure fluids. Especially for temperatures about 160 °C, mixtures like propane/isobutane, isobutane/isopentane, or R227ea/R245fa show lower electricity generation costs compared to the most efficient pure fluid. In case of a geothermal fluid temperature of 120 °C, R227ea and propane/isobutane are cost-efficient working fluids. The uncertainties regarding fluid properties of zeotropic mixtures, mainly affect the heat exchange surface. However, the influence on the determined economic parameter is marginal. In general, zeotropic mixtures are a promising approach to improve the economics of geothermal ORC systems. Additionally, the use of mixtures increases the spectrum of potential working fluids, which is important in context of present and future legal requirements considering fluorinated refrigerants.