0
Research Papers: Gas Turbines: Heat Transfer

The Application of Rotary Vane Expanders in Organic Rankine Cycle Systems—Thermodynamic Description and Experimental Results

[+] Author and Article Information
Zbigniew Gnutek

e-mail: zbigniew.gnutek@pwr.wroc.pl

Piotr Kolasiński

e-mail: piotr.kolasinski@pwr.wroc.pl
Department of Thermodynamics,
Wrocław University of Technology,
Institute of Heat Engineering
and Fluid Mechanics,

Wybrzeże Wyspiańskiego 27,
Wrocław 50-354, Poland

Contributed by the IC Engine Division of ASME for publication in the Journal of Engineering for Gas Turbines and Power. Manuscript received February 27, 2012; final manuscript received January 28, 2013; published online May 20, 2013. Assoc. Editor: Piero Colonna.

J. Eng. Gas Turbines Power 135(6), 061901 (May 20, 2013) (10 pages) Paper No: GTP-12-1049; doi: 10.1115/1.4023534 History: Received February 27, 2012; Revised January 28, 2013

Small (10–100 kW) and micro (0.5–10 kW) Organic Rankine Cycle (ORC) power systems are nowadays considered for local and domestic power generation. Especially interesting are micropower applications for heat recovery from dispersed low potential (85–150 °C) waste and renewable heat sources. Designing and implementing an ORC system dedicated to energy recovery from such a source is difficult. A proper working fluid must be selected together with a suitable expander. Volumetric machines can be adopted as a turbine alternative in small-capacity applications under development, like, e.g., domestic cogeneration. Scroll and screw expanders are a common choice. However, scroll and screw expanders are complicated and expensive. Vane expanders are mechanically simple, commercially available and cheap. This paper documents a study providing the preliminary analysis of the possibility of employing vane-expanders in mini-ORC systems. The main objective of this research was therefore a comprehensive analysis of the use of a vane expander for continuous operation with a low-boiling working fluid. A test-stand was designed and set up starting from system models based on thermodynamic analysis. Then, a series of experiments was performed using the test-stand. Results of these experiments are presented here, together with a model of multivane expanders and a thermodynamic-based method to select the working fluid. The analysis presented in this paper indicates that multivane expanders are a cheap and mechanically simple alternative to other expansion devices proposed for small-capacity ORC systems.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

The relationship between the operational frequency and the working chamber size for volumetric machines [9]. The volume of working chambers in different machine types was recalculated to the volume of the sphere with radius ru. The ru numerical value is presented on a graph with the corresponding machine operational frequency. 1—rotary-blower for coke-oven gas, 2—diesel engine, 3—aircraft model engine, 4—piston vacuum pump, 5—large piston marine engine, 6—small screw compressor, 7—refrigerating piston compressor, 8—rotary multivane compressor, 9—vane pneumatic engine, 10—slow-speed piston steam engine, 11—piston motorbike engine, 12—Wankel engine.

Grahic Jump Location
Fig. 2

The simplified scheme of the multivane expander [17]

Grahic Jump Location
Fig. 3

The comparison between the ideal and the real multivane expander thermodynamic cycles in the p-V plane [17,18]. (a) ideal cycle, (b) real cycle.

Grahic Jump Location
Fig. 4

The relationship σ = f(αe2, z) for κ = 1.4 [17]

Grahic Jump Location
Fig. 5

The relationship between P¯ and αe2 for κ = 1.4 [17]

Grahic Jump Location
Fig. 6

The ORC system with multistage expansion

Grahic Jump Location
Fig. 7

The heat source isobaric cooling curves [26]

Grahic Jump Location
Fig. 8

The isobaric cooling of the heat source in T-s diagram [26]

Grahic Jump Location
Fig. 9

The thermal characteristic of the heat source (histogram) [26]

Grahic Jump Location
Fig. 10

The process of isentropic working fluid expansion in the ORC system [26]

Grahic Jump Location
Fig. 11

The w = f(THS) diagram [26]

Grahic Jump Location
Fig. 12

Ws = f(σ) diagram [26], referred to the heat source whose temperature profile in the T-s diagram is depicted in Fig. 9

Grahic Jump Location
Fig. 13

The simplified scheme of the ORC system utilizing a vane expander at the Research Laboratory of the Department of Thermodynamics at the Wrocław University of Technology 1—gas central eating boiler, 2—evaporator, 3—working fluid pump, 4—working fluid reservoir, 5—plate condenser, 6—multivane expanders with generators

Grahic Jump Location
Fig. 14

The general view of the ORC system whose scheme is presented in Fig. 13

Grahic Jump Location
Fig. 15

The variation of the ORC system efficiency during the experiment. The drop in efficiency at τ = 150 is due to the closing of the vapor inlet to the first vane expander.

Grahic Jump Location
Fig. 16

The relation between the system efficiency and working fluid mass flow

Grahic Jump Location
Fig. 17

The variation of the expander power output

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In