The present study illustrates the development of a detailed model to estimate the part-load performance of an ammonia closed OTEC system for on-shore installations. A previously published Matlab® suite is extended by accounting for off-design conditions in terms of variable seawater temperature and mass flow on the cycle performance. The off-design behavior of each component is thoroughly discussed, with particular attention devoted to the single-stage axial-flow turbine, whose performance maps are obtained by means of three-dimensional CFD simulations. Assuming a representative plant sized for warm seawater temperature of 28 °C and cold seawater temperature of 4 °C (8500 kg/s taken from 1000 m depth), the model predicts an annual electricity yield of 15.963 GWh_e and LCOE of 316 €/MWh_e when including seawater measured data of a simile-Hawaiian site. Moreover, a sensitivity analysis is assessed in order to identify the best design parameters (i.e. warm seawater temperature and cold seawater mass flow rate) that minimize the LCOE for the given location. The new design guarantees a reduction of approximately 11% of the LCOE (284 €/MWh_e). The simulation capabilities of the developed model prove it as valuable tool to estimate the OTEC competitiveness in different scenarios.

本研究说明了详细模型的开发，该模型可用于估算陆上安装的氨封闭OTEC系统的部分负荷性能。通过考虑海水温度和质量流量对循环性能的影响，对非设计条件进行了扩展，从而扩展了先前发布的Matlab®套件。彻底讨论了每个组件的偏离设计行为，特别关注了单级轴流式涡轮机，其性能图是通过三维CFD模拟获得的。假设有代表性的工厂规模为温暖的海水温度28°C和寒冷的海水温度4°C（从1000 m深度取水8500 kg / s），该模型预测年发电量为15.963 GWh _e，LCOE为316€/兆瓦时_Ë包括比喻-夏威夷遗址的海水测量数据。此外，为了确定最佳设计参数（即温暖的海水温度和寒冷的海水质量流量），需要进行灵敏度分析，以使给定位置的LCOE最小。新的设计保证减少约11％的LCOE（284€/ MWh _e）。所开发模型的仿真能力证明它是评估不同情况下OTEC竞争力的有价值的工具。