First and second law analysis of a Stirling engine with imperfect regeneration and dead volume

Harrod, J; Mago, Pedro J.; Srinivasan, Koottalai; Chamra, Louay M.

doi:10.1243/09544062jmes1651

Cited by 11 publications

(3 citation statements)

References 26 publications

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“…Harrod et al. 4 performed a first and second law analysis on an isothermal model and captured heat exchanger inefficiencies by using effectiveness definitions. All spaces were assumed to operate at a uniform pressure; therefore, flow-induced pressure drops were not included.…”

Section: Introductionmentioning

confidence: 99%

The myth about dead volume in Stirling engines

Gschwendtner

Bell

2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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The effect of dead volume on the power output and efficiency of an alpha-Stirling engine is investigated in the form of an exploratory parameter study using the third-order simulation software Sage. This paper aims at identifying the underlying mechanisms in order to better understand the resulting design implications of this phenomenon that is in clear contradiction to what can be found in the literature. It turns out that additional 'passive' dead volume that does not even take part in the heat transfer processes leads to a phase shift of the pressure, resulting in increased pV-work output, especially at lower heat source temperatures. Of even greater significance, dead volume has a positive effect on the efficiency at lower heat source temperatures by reducing the temperature swing in the heat exchangers and by bringing the gas temperatures closer to the wall temperatures of the respective heat exchangers, and thus increasing the effective temperature difference. Furthermore, to a large extent the beneficial effects of dead volume can also be achieved by changing the phase angle.

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Section: Introductionmentioning

confidence: 99%

The myth about dead volume in Stirling engines

Gschwendtner

Bell

2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…This regeneration concept indicates the potential for high thermal efficiencies [1]. Research on the thermodynamics and performance characteristics of Stirling engines are available in open literature [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Sizing analysis of a combined cooling, heating, and power system for a small office building using a wood waste biomass-fired Stirling engine

Harrod

Mago

Luck

2010

Int. J. Energy Res.

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SUMMARYWhen wood chips are available and used to fuel a combined cooling, heating, and power (CCHP) waste heat recovery system, they can represent an economically viable source of biomass energy that can meet a facility's electric and thermal demands. Using a Stirling engine as the CCHP prime mover provides several important advantages over conventional internal combustion engines including no additional processing of the waste wood chips, a potentially higher thermal efficiency, flexibility of fuel sources, and low maintenance. This study shows how the operational characteristics of a constant output, biomass-fired, Stirling engine-based CCHP system are affected by the performance of the individual components, including the prime mover, heat recovery system, auxiliary boiler, absorption chiller, and heating coil unit The results are assessed by examining the primary energy consumption and operational cost compared with a reference case. The analysis provides insight on the prime mover sizing and selection of each component to properly implement the system. In addition to examining the effects of each component, the effect of excess electricity production and buyback are considered.

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“…Thombare and Verma [8]offered an outline of Stirling engine operation and theory including an overview of thermodynamic models, various geometries, and operational characteristics. Harrod et al [9] presented a first and second law analysis of the Stirling cycle including the effects of the presence of dead volumes and imperfect regeneration. They presented trends for net work, thermal efficiency, and entropy generation.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of a combined cooling, heating, and power system driven by a waste biomass fired Stirling engine

Harrod

Mago

2010

Proceedings of the Institution of Mechanical Engineers, Part C:

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Due to the soaring costs and demand of energy in recent years, combined cooling, heating, and power (CCHP) systems have arisen as an alternative to conventional power generation based on their potential to provide reductions in cost, primary energy consumption, and emissions. However, the application of these systems is commonly limited to internal combustion engine prime movers that use natural gas as the primary fuel source. Investigation of more efficient prime movers and renewable fuel applications is an integral part of improving CCHP technology. Therefore, the objective of this study is to analyse the performance of a CCHP system driven by a biomass fired Stirling engine. The study is carried out by considering an hour-byhour CCHP simulation for a small office building located in Atlanta, Georgia. The hourly thermal and electrical demands for the building were obtained using the EnergyPlus software. Results for burning waste wood chip biomass are compared to results obtained burning natural gas to illustrate the effects of fuel choice and prime mover power output on the overall CCHP system performance. Based on the specified utility rates and including excess production buyback, the results suggest that fuel prices of less than $23/MWh must be maintained for savings in cost compared to the conventional case. In addition, the performance of the CCHP system using the Stirling engine is compared with the conventional system performance. This comparison is based on operational cost and primary energy consumption. When electricity can be sold back to the grid, results indicate that a wood chip fired system yields a potential cost savings of up to 50 per cent and a 20 per cent increase in primary energy consumption as compared with the conventional system. On the other hand, a natural gas fired system is shown to be ineffective for cost and primary energy consumption savings with increases of up to 85 per cent and 24 per cent compared to the conventional case, respectively. The variations in the operational cost and primary energy consumption are also shown to be sensitive to the electricity excess production and buyback rate. and power (CCHP) and combined heating and power (CHP) systems have arisen as an alternative for conventional power generation. CCHP systems are classically characterized by the use of a prime mover (such as internal combustion (IC) engines and turbine engines) coupled to a generator and driven on-site to satisfy an electrical demand of the facility. In addition, the waste heat from the prime mover is utilized to satisfy the on-site demands for cooling and heating (thermal demands). For CCHP applications, it is desirable to utilize a prime mover that has favourable

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First and second law analysis of a Stirling engine with imperfect regeneration and dead volume

Cited by 11 publications

References 26 publications

The myth about dead volume in Stirling engines

The myth about dead volume in Stirling engines

Sizing analysis of a combined cooling, heating, and power system for a small office building using a wood waste biomass-fired Stirling engine

Performance analysis of a combined cooling, heating, and power system driven by a waste biomass fired Stirling engine

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