Instantaneous steady state of pumpless organic Rankine cycle driven by low temperature heat source

doi:10.11949/j.issn.0438-1157.20170405

Abstract

Abstract:

A small scale pumpless ORC (organic Rankine cycle) system which can recover waste heat from low temperature heat resource is established to investigate the performance of the cycle. The system is mainly composed of two high efficient heat exchangers, one scroll expander, one generator, four refrigerant valves and eight water valves. The flow direction of the water and refrigerant is controlled by the valves. The water heated by electric heating boiler is used to simulate the low temperature heat resource. The temperature of the hot water ranges from 75℃ to 95℃ and the temperature gradient is 5℃. The cooling water from the cooling tower is 25℃ accordingly. The refrigerant R245fa is selected as the working fluid. The results show that the largest power output is 232 W, and the stable power output is about 230 W when the inlet water temperature is 95℃. The total time of power generation last 380 s. One more thing is that the higher inlet water temperature, the less time of power generation process. For the average steady power generation, the maximum energy efficiency is 3.92% and the minimum energy efficiency is 3.02% when the inlet water temperature is 95℃ and 85℃, respectively.

Key words: pumpless ORC, enthalpy, waste heat recovery, scroll expander, electricity generation efficiency

摘要：

建立了一套低温热源驱动的小型无泵有机朗肯循环系统，研究无泵有机朗肯循环回收利用余热发电的性能。该系统中热水温度为75～95℃，冷却水温度为25℃，选择制冷剂R245fa作为系统工质，选择涡旋膨胀机将热能转换为机械能，并通过发电机进行发电。实验结果表明当热水进口温度为95℃时，最大瞬时发电功率为232 W，并可以在250 s的时间内保持稳定在230 W左右，总的发电持续时间为380 s。随着热源水温度下降，功率输出减小，但发电持续时间增加。系统稳定发电平均效率最大为3.92%，此时热源水温度为95℃，最低为3.02%，此时热源水温度为85℃。

关键词: 无泵有机朗肯循环, 焓值, 余热回收, 涡旋膨胀机, 发电效率

CLC Number:

TK09

LU Huitong, JIANG Long, WANG Liwei, WANG Ruzhu. Instantaneous steady state of pumpless organic Rankine cycle driven by low temperature heat source[J]. CIESC Journal, 2017, 68(12): 4709-4716.

路会同, 江龙, 王丽伟, 王如竹. 低温余热驱动的无泵有机朗肯循环瞬时稳态发电性能[J]. 化工学报, 2017, 68(12): 4709-4716.

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