Thermodynamic analysis of a gamma type Stirling engine in non-ideal adiabatic conditions

Parlak, Nezaket; Wagner, Andreas; Elsner, Michael; Soyhan, Hakan Serhad

doi:10.1016/j.renene.2008.02.030

Cited by 67 publications

(25 citation statements)

References 14 publications

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“…In later years, Karabulut investigates specifically the beta free piston engines [7], whereas Parlak et al deal with the gamma engine under almost stationary flow conditions [8], and Andersen et al develop a one-dimensional model [9].…”

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confidence: 99%

Experimental and numerical study of a micro-cogeneration Stirling unit under diverse conditions of the working fluid

et al. 2015

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In the scenario of micro-cogeneration (or micro Combined Heat and Power, micro-CHP), Stirling units are a promising technology for residential applications because of high total efficiencies, favorable ratios of thermal to electrical powers and lower emissions compared to reciprocating engines and micro gas turbines. 1 The present work covers the experimental and numerical analyses of a natural gas-fired commercial unit capable of generating 8 kW of hot water (up to 15 kW with an auxiliary burner) and 1 kW of electricity. Although featuring in general a low electrical efficiency, these micro-cogeneration units are able to recover heat with a high thermal efficiency, thus qualifying positively in terms of primary energy savings. Moreover, the thermal-to-electrical power ratios of 8-to-1 (and 15-to-1 with the additional burner) are well suited for covering simultaneously the thermal and electrical loads of typical residences in continental climates. ☆This article is based on a short proceedings paper in Energy Procedia Volume 161 (2014). It has been substantially modified and extended, and has been subject to the normal peer review and revision process of the journal. This paper is included in the Special Issue of ICAE2014 edited by Prof. J Yan, Prof. DJ Lee, Prof. SK Chou, and Prof. U Desideri. AbstractMicro-cogeneration Stirling units are promising for residential applications because of high total efficiencies, favorable ratios of thermal to electrical powers and low CO as well as NO x emissions. This work focuses on the experimental and the numerical analysis of a commercial unit generating 8 kW of hot water (up to 15 kW with an auxiliary burner) and 1 kW of electricity burning natural gas. In the experimental campaign, the initial pressure of the working fluid is changed in a range from 9 to 24 bar g -20 bar g being the nominal value -while the inlet temperature of the water loop and its mass flow rate are kept at the nominal conditions of, respectively, 50 °C and 0.194 kg/s.The experimental results indicate clearly that the initial pressure of the working fluid -Nitrogen -affects strongly the net electrical power output and efficiency. The best performance for the output and efficiency of 943 W and 9.6%(based on the higher heating value of the burnt natural gas) are achieved at 22 bar g . On the other hand, the thermal power trend indicates a maximum value of 8420 W at the working pressure of 24 bar g , which corresponds to a thermal efficiency of 84.7% (again based on higher heating value). Measurements are coupled to a detailed model based on a modification of the work by Urieli and Berchowitz. Thanks to the tuning with the experimental results, the numerical model allows investigating the profiles of the main thermodynamic parameters and heat losses during the cycle, as well as estimating those physical properties that are not directly measurable. The major losses turn to be the wall parasitic heat conduction from heater to cooler and the non-unitary effectiveness of the regenerator.

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Experimental and numerical study of a micro-cogeneration Stirling unit under diverse conditions of the working fluid

et al. 2015

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“…These losses previously have been studied in [8], [19] and [20]. In addition, if they are predicted correctly, the model accuracy would reach to 95%.…”

Section: Flow Frictionmentioning

confidence: 99%

Preliminary Analysis of an Innovative Rotary Displacer Stirling Engine

2015

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Bagheri, AmirHossein. Preliminary Analysis of an Innovative Rotary Displacer StirlingEngine. Master of Science (Engineering Technology-Mechanical Systems ), December 2015, 53 pp., 5 tables, 29 figures, references, 27 titles.Stirling engines are an external combustion heat engine that converts thermal energy into mechanical work that a closed cycle is run by cyclic compression and expansion of a work fluid (commonly air or Helium) in which, the working fluid interacts with a heat source and a heat sink and produces net work. The engine is based on the Stirling cycle which is a subset of the Carnot cycle. The Stirling cycle has recently been receiving renewed interest due to some of its key inherent advantages. In particular, the ability to operate with any form of heat source (including external combustion, flue gases, alternative (biomass, solar, geothermal) energy) provides Stirling engines a great flexibility and potential benefits since it is convinced as engines running with external heat sources. However, several aspects of traditional Stirling engine configurations (namely, the Alpha, Beta, and Gamma), specifically complexity of design, high cost, and relatively low power to size and power to volume ratios, limited their widespread applications to date. This study focuses on an innovative Stirling engine configuration that features a rotary displacer (as opposed to common reciprocating displacers), and aims to utilize analytical and numerical analysis to gain insights on its operation parameters. The results are expected to provide useful design guidelines towards optimization. iii iv

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“…Stirling engines have been tested and analysed for three main configurations: the alpha-type [1,2], beta-type [3][4][5][6] and gamma-type [7][8][9][10]. There have been thorough reviews of the Stirling engine by Kongtragool and Wongwises [11], Thombare and Verma [12] and Wang et al [13].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Net Work Output between Stirling and Ericsson Cycles

Costa

MacDonald

2018

Energies

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Abstract:In this paper, we compare Stirling and Ericsson cycles to determine which engine produces greater net work output for various situations. Both cycles are for external heat engines that utilize regenerators, where the difference is the nature of the regeneration process, which is constant volume for Stirling and constant pressure for Ericsson. This difference alters the performance characteristics of the two engines drastically, and our comparison reveals which one produces greater net work output based on the thermodynamic parameters. The net work output equations are derived and analysed for three different scenarios: (i) equal mass and temperature limits; (ii) equal mass and pressure or volume; and (iii) equal temperature and pressure or volume limits. The comparison is performed by calculating when both cycles produce equal net work output and then analysing which one produces greater net work output based on how the parameters are varied. In general, the results demonstrate that Stirling engines produce more net work output at higher pressures and lower volumes, and Ericsson engines produce more net work output at lower pressures and higher volumes. For certain scenarios, threshold values are calculated to illustrate precisely when one cycle produces more net work output than the other. This paper can be used to inform the design of the engines and to determine when a Stirling or Ericsson engine should be selected for a particular application.

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Thermodynamic analysis of a gamma type Stirling engine in non-ideal adiabatic conditions

Cited by 67 publications

References 14 publications

Experimental and numerical study of a micro-cogeneration Stirling unit under diverse conditions of the working fluid

Experimental and numerical study of a micro-cogeneration Stirling unit under diverse conditions of the working fluid

Preliminary Analysis of an Innovative Rotary Displacer Stirling Engine

Comparison of the Net Work Output between Stirling and Ericsson Cycles

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