External load resistance effect on the free piston expander-linear generator for organic Rankine cycle waste heat recovery system

Hou, Xiaochen; Zhang, Hongguang; Xu, Yonghong; Yu, Fei; Zhao, Tenglong; Tian, Yaming; Yang, Yuxin; Zhao, Rui

doi:10.1016/j.apenergy.2018.01.020

Cited by 42 publications

(11 citation statements)

References 39 publications

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“…In general, the scroll expander is the most suitable expander for a small-scale ORC system [39]. Recently, several research efforts have aimed to accomplish better performance by using a free-piston expander [40]. Moreover, two heat exchangers serve as the evaporator and condenser for conventional ORC systems.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Wang

Jiang

et al. 2019

Energies

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Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is improved by up to 3.27%. Additionally, the exergy destruction using TDP can be reduced in the evaporator and condenser. The highest exergy efficiency in the evaporator is 96.9%, an improvement of 62% in comparison with that of the conventional ORC, i.e., 59.9%. Thus, the small-scale solar ORC system using TDP is more promising for household application.

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Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Wang

Jiang

et al. 2019

Energies

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“…When considering ORC systems of net electrical power output around 1 kWe, scroll and screw expanders are a well-known technology for energy conversion, but when the temperature of the hot source falls below 100 • C, other machines have to be used. For example, an innovative way to generate a small amount of electrical power (a few Watts) is to utilize free-piston expanders [5,6]. From the experimental side, the use of a positive displacement machine requires a specific test-rig to reproduce the actual operating conditions in terms of pressure, fluid characteristics and loads.…”

Section: Introductionmentioning

confidence: 99%

Pressure Pulsation and Cavitation Phenomena in a Micro-ORC System

et al. 2019

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Micro-ORC systems are usually equipped with positive displacement machines such as expanders and pumps. The pumping system has to guarantee the mass flow rate and allows a pressure rise from the condensation to the evaporation pressure values. In addition, the pumping system supplies the organic fluid, characterized by pressure and temperature very close to the saturation. In this work, a CFD approach is developed to analyze from a novel point of view the behavior of the pumping system of a regenerative lab-scale micro-ORC system. In fact, starting from the liquid receiver, the entire flow path, up to the inlet section of the evaporator, has been numerically simulated (including the Coriolis flow meter installed between the receiver and the gear pump). A fluid dynamic analysis has been carried out by means of a transient simulation with a mesh morphing strategy in order to analyze the transient phenomena and the effects of pump operation. The analysis has shown how the accuracy of the mass flow rate measurement could be affected by the pump operation being installed in the same circuit branch. In addition, the results have shown how the cavitation phenomenon affects the pump and the ORC system operation compared to control system actions.

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“…However, the ORP compressor has a shorter cyclic period; it means less time for air exchange. In these works, , piston movements and speeds were indicators to evaluate compressor performance because the piston movements indicated cylinder volume change rates, which was one of the main factors determining in-cylinder pressure evolutions. However, cylinder volume change rates of the ORP compressor are determined by two adjacent piston movements, as shown in Figure .…”

Section: Methodsmentioning

confidence: 99%

Preliminary Investigations of an Opposed Rotary Piston Compressor for the Air Feeding of a Polymer Electrolyte Membrane Fuel Cell System

et al. 2020

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Automotive polymer electrolyte membrane fuel cell systems are attracting much attention, driven by the requirements of low automotive exhaust emissions and energy consumption. A polymer electrolyte membrane fuel cell system provides opportunities for the developments in different types of air compressors. This paper proposed an opposed rotary piston compressor, which had the merits of more compact structures, less movement components, and a high pressure ratio, meeting the requirements of polymer electrolyte membrane fuel cell systems. Preliminary performance evaluations of the opposed rotary piston compressor were conducted under various scenarios. This will make a foundation for optimizations of outlet pipe layouts of the compressor. A three-dimensional numerical simulation approach was used; further, in-cylinder pressure evolutions, fluid mass flow rates, and P – V diagrams were analyzed. It indicated that the cyclic period of the opposed rotary piston compressor was half of reciprocating piston compressors. The specific mass flow rate of the compressor is in the range of 0.094–0.113 kg·(s·L) −1 for the given scenarios. Outlet ports 1 and 2 dominated the mass flow in the discharge process under scenarios 1, 3, and 4. In-cylinder pressure profiles show multipeaks for all of these scenarios. In-cylinder pressure increased rapidly in the compression process and part of the discharge process, which led to high energy consumption and low adiabatic efficiency. The maximum adiabatic efficiency is approximately 43.96% among the given scenarios.

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External load resistance effect on the free piston expander-linear generator for organic Rankine cycle waste heat recovery system

Cited by 42 publications

References 39 publications

Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Pressure Pulsation and Cavitation Phenomena in a Micro-ORC System

Preliminary Investigations of an Opposed Rotary Piston Compressor for the Air Feeding of a Polymer Electrolyte Membrane Fuel Cell System

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