太阳能有机朗肯循环系统的实验特性

为研究中低温太阳能驱动的有机朗肯循环系统的性能,设计并建造了太阳能驱动的有机朗肯循环实验台.实验中以R245fa为有机朗肯循环工质,以WD350导热油为槽式集热器循环工质,对太阳能有机朗肯循环系统进行了实验研究.实验结果表明,当太阳直射辐射强度在400 W·m^-2左右时,集热器出口导热油温度可达 140℃.当集热器出口导热油温度在 110℃附近时,集热器集热效率可达60%左右.在该热源条件下,动力循环部分从基本循环模式切换到回热循环模式时,测算效率从9.3%提升到10.8%,实测循环效率从1.57%提升到1.67%,提升了6.07%.实测循环系统 效率在10%左右,回热模式下略高于基本循环模式.实验中还考察了不同工质流量下的有机朗肯循环性能,在工质流量为 6.88 kg·min^-1时,得到的最大实测平均功率为386.27 W.一定热源温度下,随着工质流量的增加,膨胀机进口压力增加,循环输出功也增加;在一定的工质流量下,随着热源温度的升高,膨胀机进口的温度提高,进口压力也升高,循环输出功也增加.

Experimental characteristics of solar organic Rankine cycle system

To study the performance of solar organic Rankine cycle (ORC) system, a low temperature solar ORC system is proposed and constructed. The system employs R245fa as the working fluid in the power cycle and WD350 heat transfer oil as the heat transfer fluid in the solar collector. The experimental installation consists of a trough solar collector, a screw expander, a working fluid pump, a heat regenerator, a water cooled condenser, and a vapour generator. When the solar beam radiation is about 400 W·m^-2 in the experiment, the thermal oil temperature at the outlet of solar heat collector can reach up to 140℃. The collecting efficiency of the collector is 60% at the outlet oil temperature of 110℃. When the working mode of system changes from basic ORC to regenerative cycle, the calculated efficiency of the system is improved from 9.3% to 10.8%, and the experimental value is improved from 1.57% to 1.67%. The measured exergy efficiency of the system is about 10%. The value under regenerative cycle mode is higher than that under the basic ORC mode. The cycle performance at different working fluid flow rates was also studied. The measured maximum average power output was obtained at 386.27 W and working fluid flow rate of 6.88 kg·min^-1. With the increase of working fluid flow rate, both expander inlet pressure and work output increase at fixed heat source temperature. With the increase of heat source temperature, the expander inlet temperature and pressure, and the power output increase at fixed flow rate.