基于超临界CO2循环的地热与太阳能混合系统研究

超临界CO₂循环可以耦合较低温度的地热和较高温度的太阳能热组成混合热源发电系统。相比能量分析方法，火用分析方法更便于分析混合系统对提高能量利用率的作用，以及识别造成可用能损失的设备和过程。115℃地热和200℃地热分别与采用槽式聚光集热技术的太阳能热组成混合热源，构成简单回热超临界CO₂循环。分析结果表明：混合系统的火用效率比单纯太阳能热的循环系统提高了5% ~ 10%；太阳能聚光集热器的?损失最大，占80%以上，其次是除预冷器以外的各类换热器以及透平；相比之下，压缩机和预冷器的火用损失较小。减少?损失的关键是提高太阳能聚光集热器和换热器的性能，包括提高集热管运行温度，以及提高换热器效能。

Study on Hybrid Geothermal-Solar Energy System with Supercritical Carbon Dioxide Cycle

Supercritical carbon dioxide cycle can be composed to a hybrid power system by combining low temperature geothermal energy with high temperature solar energy. Compared with energy analysis method, exergy analysis method is better to analyze the effect of hybrid system for the improvement of the energy utilization efficiency, as well as the identification of equipment and process causing the loss of available energy. A simple regenerative cycle was configured, using 115^oC and 200^oC geothermal energy respectively, combined with solar energy with parabolic trough concentrating receiving technology. Analysis results showed that the exergy efficiency of hybrid system was 5% ~ 10% higher than system with pure solar energy; solar energy concentrating and receiving devices caused the largest portion of exergy loss, accounting for more than 80%, followed by various types of heat exchangers except precooler and the turbine; in contrast, the compressor and the precooler caused the lest exergy loss. Improvement of the performance of solar energy concentrating and receiving devices and the heat exchangers was the key to cut down the exergy loss, including increase in operating temperature of solar receiver, and the effectiveness of heat exchangers.