Development and validation of a single-piston free piston expander-linear generator for a small-scale organic Rankine cycle

To improve the energy efficiency of internal combustion engines, this study develops a single-piston free piston expander-linear generator (FPE-LG) for a small scale organic Rankine cycle (ORC) in a waste heat recovery system. The prototype can operate continuously and stably, thereby indicating tha...

Full description

Saved in:
Bibliographic Details
Published in:Energy (Oxford) 2018-10, Vol.161, p.809-820
Main Authors: Tian, Yaming, Zhang, Hongguang, Li, Jian, Hou, Xiaochen, Zhao, Tenglong, Yang, Fubin, Xu, Yonghong, Wang, Xin
Format: Article
Language:English
Subjects:
Cylinders
Energy efficiency
Engine valves
Exhaust
Free piston expander–linear generator
Generators
Heat recovery
Heat recovery systems
Internal combustion engines
Load resistance
Organic Rankine cycle
Output performance
Pressure
Prototype test
Prototypes
Rankine cycle
Velocity
Waste heat recovery
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:To improve the energy efficiency of internal combustion engines, this study develops a single-piston free piston expander-linear generator (FPE-LG) for a small scale organic Rankine cycle (ORC) in a waste heat recovery system. The prototype can operate continuously and stably, thereby indicating that the single-piston FPE-LG has a feasible working principle. The operation characteristics of FPE-LG are revealed, and the effects of the intake valve opening time (IVOT) and the exhaust valve opening time (EVOT) on the output performance are investigated. The experimental results reveal that the piston can run at a relatively high velocity near the dead centers, and peak acceleration is typically achieved when the piston arrives at the operation left/right dead centers (OLDC/ORDC). The piston stroke length is decreased significantly as the operating frequency is increased. The peak power output, peak in-cylinder pressure, peak velocity of the free piston, and utilization ratio of the piston stroke (η) are increased as the external load resistance is increased. In addition, η increases with longer IVOT and can reach up to 67.4% when the IVOT is 40 ms. The exhaust pressure decreases as the EVOT is increased, and the power output can be improved by regulating the IVOT rather than the EVOT. •A novel test rig of single-piston free piston expander-linear generator prototype is developed.•Performances and working principles of the single-piston FPE-LG are presented.•The concept of the utilization ratio of piston stroke length (η) is proposed.•Effects of intake/exhaust valve opening time on the FPE-LG performance are investigated.
ISSN:0360-5442
1873-6785
DOI:10.1016/j.energy.2018.07.192