Thermodynamic performance assessment of an ammonia–water Rankine cycle for power and heat production
Thermodynamic performance assessment of an ammonia–water Rankine cycle for power and heat production
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DOI：
10.1016/j.enconman.2010.05.014
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发表时间：
2010-12
影响因子：
10.4
通讯作者：
W. R. Wagar;C. Zamfirescu;I. Dincer
中科院分区：
文献类型：
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作者：
W. R. Wagar;C. Zamfirescu;I. Dincer
在本文中，氨水为基础的朗肯循环进行了热力学分析，可再生能源发电，如太阳能，地热，生物质，海洋热，核能以及工业废热。由于氨水混合物的性质，其浓度的变化允许热力学循环适应可再生能源的波动，这是相对于其他工作流体的重要优势。工作流体行为的非线性要求每个循环必须根据多个参数进行优化。已经开发了一个模型，以优化热力循环的最大功率输出，并进行了参数研究。系统的最低温度状态是固定的，另外三个参数是研究的变量，即最高系统温度，氨浓度和能量比，这是一个新引入的参数。能量比指示膨胀状态的相对位置，并且根据能量比来定义。该研究在0 - 0.5的浓度范围内进行，研究的最高温度在极端情况下在75 ° C和350 ° C之间变化，并且从饱和液体到过热蒸汽的能量比。预测了最佳膨胀能比。循环效率受浓度和温度的显著影响。取决于源温度，循环能量效率在5%和35%之间变化，代表高达卡诺极限的65%。最佳的能量比已被确定为几个浓度和图表报告。
In this paper, an ammonia–water based Rankine cycle is thermodynamically analyzed for renewable-based power production, e.g. solar, geothermal, biomass, oceanic-thermal, and nuclear as well as industrial waste heat. Due to the nature of the ammonia–water mixture, changes in its concentration allow thermodynamic cycles to adapt to fluctuations in renewable energy sources, which is an important advantage with respect to other working fluids. The non-linearity of the working fluid’s behaviour imposes that each cycle must be optimized based upon several parameters. A model has been developed to optimize the thermodynamic cycle for maximum power output and carry out a parametric study. The lowest temperature state of the system is fixed, and three other parameters are variables of study, namely, maximum system temperature, ammonia concentration and energy ratio, which is a newly introduced parameter. Energy ratio indicates the relative position of the expansion state and is defined in terms of enthalpies. The study is conducted over a concentration range of 0–0.5, the maximum temperature studied varies between 75°C and 350°C for extreme cases, and the energy ratio from saturated liquid to superheated vapour. As a result, the optimal expansion energy ratio is predicted. The cycle efficiencies are drastically affected by the concentrations and temperatures. Depending on the source temperature, the cycle energy efficiency varies between 5% and 35% representing up to 65% of the Carnot limit. The optimal energy ratio has been determined for several concentrations and reported graphically.