Experimental investigation of a revolving vane expander in a micro-scale organic Rankine cycle system for low-grade waste heat recovery

Impact of the Lubricant on a Modified Revolving Vane Expander (M-RVE) in an Organic Rankine Cycle System

“…Following the assumptions described in Section 2, an estimation of the effect of the lubricant oil on the evaporator is also presented. Since the experimental studies come with uncertainties due to the precision of the measurement tools and the experimental data, the combined uncertainty associated with parameter U is obtained using Equation (15). U is a function of several independent Energies 2023, 16, 5340 9 of 17 variables of u i , j is the confidence level indicator (equal to 2 corresponding to a 95% level of confidence in this study), and δu i is the uncertainty associated with the parameter k i [28].…”

“…At the premises of the Department of Mechanical and Mechatronics Engineering of the University of Auckland, New Zealand, a micro-scale ORC system test bench was developed, and an M-RVE prototype was tested. R134a [15] and POE (Emkarate-RL46H) [22] were used as the working fluid and lubricant oil, respectively. The test rig included an oil separator circuit, as reported in Figure 1 (orange lines represent the oil circuit), which illustrates the schematic and piping and instrumentation diagram of the test rig used for this study.…”

“…Figure 2 illustrates the schematic of the M-RVE prototype. In the current study, a brand-new Teflon-made end-face sealant disk was used in the M-RVE prototype as signs of wear were observed on the disk when disassembled [15]. Moreover, the rotary seals were replaced.…”

“…Krishna et al [14] studied a rotating spool expander for ORC applications. Instead, Naseri et al [15] studied the performance of a modified revolving vane expander (M-RVE) in a micro-scale ORC system for WHR applications for the first time. Their results showed an isentropic efficiency of up to 42.5% for the M-RVE expander.…”