Thermodynamic analysis of a Stirling engine including dead volumes of hot space, cold space and regenerator

Kongtragool, Bancha; Wongwises, Somchai

doi:10.1016/j.renene.2005.03.012

Cited by 140 publications

(64 citation statements)

References 7 publications

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“…As the speed increases, the isothermal expansion and compression processes become more adiabatic [8,13,17], which produces lower cycle work and efficiency than the isothermal processes [9,18,19]. The efficiency is even worse than the ideal adiabatic efficiency due to the non-adiabatic cylinders and non-isothermal heat exchangers that increase the irreversibilities [20][21][22].…”

Section: Heat Exchangermentioning

confidence: 99%

Parametric Study of an Air Charged Franchot Engine with Novel Hot and Cold Isothermalizers

Daoud

Friedrich

2017

Inventions

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Abstract:The Stirling engine is an external combustion engine that uses heat exchangers to enhance the addition and removal of energy. This makes the engine power-dense but expensive, less efficient and complicated. In this contribution, the Stirling engine based on the Franchot engine has novel cylindrical fins working as isothermalizers to improve heat transfer without the complications of heat exchangers. Enhancing the power density by isothermalizing work spaces is compared to the bare cylinder optimized by varying the phase angle. The theoretical analysis shows that both the adiabatic and isothermal fins increase the power and efficiency, achieving the Curzon and Ahlborn efficiency at the maximum power point. In comparison to the phase angle method, the finned engine resulted in much lower gas mass flow rate, which leads to a reduction in the regenerator pumping and enthalpy losses. Thus, the Stirling engine has the potential to be simple, cheap, efficient and power-dense, and thus can be used effectively for different applications.

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Section: Heat Exchangermentioning

confidence: 99%

Parametric Study of an Air Charged Franchot Engine with Novel Hot and Cold Isothermalizers

Daoud

Friedrich

2017

Inventions

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“…Analyzing the thermodynamic cycle of an SE [21], the total work produced by an imperfect-regeneration SE with dead volumes during a cycle is defined in Equation (7):…”

Section: Power Output Simulationmentioning

confidence: 99%

Development of a Transient Model of a Stirling-Based CHP System

Ulloa¹,

Mı́guez

Porteiro

et al. 2013

Energies

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Although the Stirling engine was invented in 1816, this heat engine still continues to be investigated due to the variety of energy sources that can be used to power it (e.g., solar energy, fossil fuels, biomass, and geothermal energy). To study the performance of these machines, it is necessary to develop and simulate models under different operating conditions. In this paper, we present a one-dimensional dynamic model based on components from Trnsys: principally, a lumped mass and a heat exchanger. The resulting model is calibrated using GenOpt. Furthermore, the obtained model can be used to simulate the machine both under steady-state operation and during a transient response. The results provided by the simulations are compared with data measured in a Stirling engine that has been subjected to different operating conditions. This comparison shows good agreement, indicating that the model is an appropriate method for transient thermal simulations. This new proposed model requires few configuration parameters and is therefore easily adaptable to a wide range of commercial models of Stirling engines. A detailed analysis of the system results reveals that the power is directly related to the difference of temperatures between the hot and cold sources during the transient and steady-state processes.

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“…5 We within the 17-year period starting from the minimum fuel load at BOM. Q in and T h are decreasing with YOM, and Q rej and T c remain almost constant.…”

Section: Asrg Performance Characteristic Under Yommentioning

confidence: 99%

Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB

Wang

2011

9th Annual International Energy Conversion Engineering Conference

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This paper presents a one-dimensional steady-state mathematical thermal power model of the ASRG. It aims to provide a guideline of understanding how the ASRG works and what can change its performance. The thermal dynamics and energy balance of the generator is explained using the thermal circuit of the ASRG. The Stirling convertor performance map is used to represent the convertor. How the convertor performance map is coupled in the thermal circuit is explained. The ASRG performance characteristics under i) different sink temperatures and ii) over the years of mission (YOM) are predicted using the one-dimensional model. Two Stirling converter control strategies, i) fixing the hot-end of temperature of the convertor by adjusting piston amplitude and ii) fixing the piston amplitude, were tested in the model. Numerical results show that the first control strategy can result in a higher system efficiency than the second control strategy when the ambient gets warmer or the general-purpose heat source (GPHS) fuel load decays over the YOM. The ASRG performance data presented in this paper doesn't pertain to the ASRG flight unit. Some data of the ASRG engineering unit (EU) and flight unit that are available in public domain are used in this paper for the purpose of numerical studies. IntroductionThe advanced Stirling radioisotope generator (ASRG) (Refs. 1 to 3) is being developed for multimission applications to provide a high-efficiency power source alternative to radioisotope thermoelectric generators (RTGs). The ASRG efficiency could reach 28 to 32 percent, which results in reducing the required amount of radioisotope by roughly a factor of 4 compared to RTGs. Thus, because of the limited supply of Pu-238, utilization of the ASRG can extend radioisotope power available for future space science missions, such as deep-space missions, large planetary surface rovers, and systems in support of human exploration activities.An overview of the ASRG is shown in Figure 1. The ASRG consists of two advanced Stirling convertors (ASCs) enclosed in the housing; each has a general purpose heat source (GPHS) attached at the hot end to provide the heat. A gas management valve (GMV) and pressure relief device (PRD) are located at the top of the housing. The housing with attached fins radiates the heat to the environment. The GMV is used to maintain a near-atmosphere pressure of inert gas inside the housing during ground operations. This gas is permanently vented to vacuum by the PRD when the ambient becomes vacuum. The ASC control unit (ACU) is separate from the ASRG housing. It converts the AC signals from both ASC to 28 to 34 VDC for a typical spacecraft electrical bus. The controller is used to maintain synchronized displacer/piston movement of the two directionally opposed Stirling convertors to minimize induced disturbance to the spacecraft and its precision instrumentation.An ASC consists of a free-piston Stirling converter and an integral linear alternator that converts the piston reciprocating motion to electrical power...

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Thermodynamic analysis of a Stirling engine including dead volumes of hot space, cold space and regenerator

Cited by 140 publications

References 7 publications

Parametric Study of an Air Charged Franchot Engine with Novel Hot and Cold Isothermalizers

Parametric Study of an Air Charged Franchot Engine with Novel Hot and Cold Isothermalizers

Development of a Transient Model of a Stirling-Based CHP System

Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB

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