Experimental Investigation of a Small-Scale ORC Power Plant Using a Positive Displacement Expander with and without a Regenerator
Experimental Investigation of a Small-Scale ORC Power Plant Using a Positive Displacement Expander with and without a Regenerator
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DOI：
10.3390/en12081452
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发表时间：
2019-04
期刊：
影响因子：
3.2
通讯作者：
P. Collings;Andrew Mckeown;E. Wang;Zhibin Yu
中科院分区：
文献类型：
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作者：
P. Collings;Andrew Mckeown;E. Wang;Zhibin Yu
虽然大规模ORC发电厂是相对成熟的技术，但其应用于小规模发电厂（即，10千瓦以下）仍然遇到一些技术挑战。正位移膨胀器主要用于这种小规模应用。然而，它们的内置膨胀比通常小于最大利用热源所需的膨胀比，导致膨胀不足，从而导致膨胀机出口处的焓较高，并最终导致热效率较低。为了克服这个问题，一种可能的解决方案是引入内部热交换器（即，所谓的回热器）以回收离开膨胀器的焓，并在液态工作流体进入蒸发器之前将其用于预热液态工作流体。在本文中，一个小规模的实验台（与1千瓦的额定功率）的设计和建造，是能够在再生和非再生模式之间切换，使用R245fa作为工作流体。在各种工况下进行了测试，结果表明，回热式换热器可以在发生欠膨胀时回收相当多的热量，提高循环效率。
While large-scale ORC power plants are a relatively mature technology, their application to small-scale power plants (i.e., below 10 kW) still encounters some technical challenges. Positive displacement expanders are mostly used for such small-scale applications. However, their built-in expansion ratios are often smaller than the expansion ratio required for the maximum utilisation of heat sources, leading to under expansion and consequently higher enthalpy at the outlet of the expander, and ultimately resulting in a lower thermal efficiency. In order to overcome this issue, one possible solution is to introduce an internal heat exchanger (i.e., the so-called regenerator) to recover the enthalpy exiting the expander and use it to pre-heat the liquid working fluid before it enters the evaporator. In this paper, a small-scale experimental rig (with 1-kW rated power) was designed and built that is capable of switching between regenerative and non-regenerative modes, using R245fa as the working fluid. It has been tested under various operating conditions, and the results reveal that the regenerative heat exchanger can recover a considerable amount of heat when under expansion occurs, increasing the cycle efficiency.