海洋温差发电系统蒸发压力及工质优选分析  

Numerical analysis on evaporating pressure and working fluids of ocean thermal energy conversion

作　　者：李大树[1,2] 张理[1] 

机构地区：[1]中国海洋石油总公司研究总院,北京100028 [2]中国石油大学(北京)博士后流动站,北京102249

出　　处：《可再生能源》2017年第7期1101-1106,共6页Renewable Energy Resources

基　　金：中国海洋石油总公司科技项目(CNOOC-KJZHKYZY2016-01-02)

摘　　要：文章基于热力学原理,建立了海洋温差发电系统仿真模型,分析了R717,R134a和R600这3种工质系统的性能参数随蒸发压力的变化。研究结果表明:随蒸发压力的增大,不同工质系统的蒸发器和冷凝器的热负荷和海水泵功率均近似呈幂递减的变化趋势,不同工质系统的泵功率均近似呈指数递增的变化趋势,不同工质系统的质量流量均近似呈幂递减的变化趋势,不同工质系统的热效率均近似呈对数递增的变化趋势;蒸发压力越大,R717和R600工质系统的单位换热面积发电量越大,但R134a工质系统的单位换热面积发电量随蒸发压力的增加存在峰值;在不同工质的饱和蒸汽压力下,R600工质系统的单位换热面积发电量最大,但其透平进出口压降较小,乏汽温度高,工质流量大,导致透平尺寸较大;R717工质系统具有较大的蒸发压力操作范围,且其热效率较大,单位换热面积发电量在合适的范围内,适用于海洋温差能发电系统。Based on the basic thermodynamic principles, a numerical ocean thermal energy conversion model was developed. The effect of evaporating pressure on performances for R717,R134 a and R600 systems were analyzed. The results show that the thermal load and power of ocean water pump decreases as evaporating pressure increases. The power of working fluid pump exponential increases with increasing evaporating pressure. The mass flow rate of working fluid decreases with increasing evaporating pressure. The thermal efficiency logarithmically increases with increasing evaporating pressure. As saturated vapor pressure of working fluid increases, the thermal efficiency increases. The larger evaporating pressure is, the higher power generation for unit heat transfer area of R717 and R600 systems are. For R134 a system, the power generation for unit heat transfer area arrives at its maximum at 700 k Pa. R600 has the largest power generation for unit heat transfer area.However, its pressure difference between turbine inlet and outlet is lower, its exhaust steam temperature is higher, and its working fluid mass flow is larger, so it has a larger turbine size. R717 system has a larger thermal efficiency and operational range of evaporating pressure, and its power generation for unit heat transfer area is in a suitable range, which can be used in ocean thermal energy conversion system.

关 键 词：海洋温差能发电 蒸发压力 循环工质 数值仿真 

分 类 号：P743.4[天文地球—海洋科学] TK114[动力工程及工程热物理—热能工程]