An experimental study on operation characteristics of the organic Rankine cycle system under the single-and multiple-variables regulation. (October 2020)

• Record Type: Journal Article
• Authors: Bai, Mengjie; Zhang, Ying; Deng, Shuai; Zhao, Li; Zhao, Ruikai; Lu, Yani
• Is Part Of: Sustainable energy technologies and assessments. Volume 41(2021)
• Publication Date: 2020-10
• Subjects: Organic Rankine cycle -- Operation characteristics -- Multiple-variables regulation -- Single-variable regulation; Renewable energy sources -- Periodicals; Energy development -- Technological innovations -- Periodicals; Electric power production -- Periodicals; Energy storage -- Periodicals; 333.79
• DOI: 10.1016/j.seta.2020.100785
• Languages: English
• ISSNs: 2213-1388

Abstract

Highlights: Operation characteristics of the ORC system are analyzed on a kW-scale test bench. The experiments included single-and multiple-variables regulation were conducted. The effective regulation variables were verified according to the different regulation tests. The appropriate regulation manner was explored to improve the system performance. Abstract: This work aims to investigate the operation characteristics of an organic Rankine cycle (ORC) system under the variable mass flow rate of the working fluid ( m ̇ wf ), such as the flow excursion in the field of direct vapor generation (DVG) systems. Besides, the mass flow rate of cooling source ( m ̇ cs ) was verified as an effective manipulated variable to respond the variation of m ̇ wf, which was an easily available freedom in the ORC system. The operation characteristic was tested respectively for m ̇ wf and m ̇ cs, where the change form of the single variable was rectangular-wave steps with different amplitudes. To verify the effectiveness of regulating m ̇ cs, the operation characteristics under the changes of multiple variables including the m ̇ wf and m ̇ cs were tested. The results indicate that the m ̇ wf dominates the variation of operation parameters of the ORC apparently, especially the evaporation pressure. Specifically, the evaporation pressure increases about 26.10 kPa as the m ̇ wf increases about 0.01 kg/s. The m ̇ cs also affects the operation parameters, which shows the opposite trend in evaporation pressure and condensing pressure compared with the increase of m ̇ wf . The results show that when the m ̇ wf increases, the increase of pressure can be reduced and the thermal efficiency can be improved by regulating the m ̇ cs in the same direction simultaneously. The increase of the theoretical thermal efficiency of the system is about 11.21% when only the m ̇ wf is inclined 0.01 kg/s, while it is 18.00% when the m ̇ cs is inclined 0.12 kg/s at the same time. The experimental findings enable to give a reference on designing control strategies for the DVG ORC systems.