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

Ulloa, Carlos; Mı́guez, J.L.; Porteiro, Jacobo; Eguía, P.; Vallejo, Javier P.

doi:10.3390/en6073115

Cited by 22 publications

(14 citation statements)

References 22 publications

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“…The steady-state performances were: 10.8% (9.7%) electric, 90.1% (81.4%) thermal, and 100.9% (91.1%) total efficiency with the main burner, all expressed with respect to the measured lower heating value and, between parenthesis, to the higher heating value of the fuel. These steady-state outcomes were in agreement with analogue measurements in the literature [15][16][17][18]. The on-off cycling results showed a significant decrease of the electric efficiency when integrated on the test period, and a modest increase in the thermal one.…”

Section: Campaign Results and Discussionsupporting

confidence: 89%

Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

et al. 2021

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Stirling units are a viable option for micro-cogeneration applications, but they operate often with multiple daily startups and shutdowns due to the variability of load profiles. This work focused on the experimental and numerical study of a small-size commercial Stirling unit when subjected to cycling operations. First, experimental data about energy flows and emissions were collected during on–off operations. Second, these data were utilized to tune an in-house code for the economic optimization of cogeneration plant scheduling. Lastly, the tuned code was applied to a case study of a residential flat in Northern Italy during a typical winter day to investigate the optimal scheduling of the Stirling unit equipped with a thermal storage tank of diverse sizes. Experimentally, the Stirling unit showed an integrated electric efficiency of 8.9% (8.0%) and thermal efficiency of 91.0% (82.2%), referred to as the fuel lower and, between parenthesis, higher heating value during the on–off cycling test, while emissions showed peaks in NOx and CO up to 100 ppm but shorter than a minute. Numerically, predictions indicated that considering the on–off effects, the optimized operating strategy led to a great reduction of daily startups, with a number lower than 10 per day due to an optimal thermal storage size of 4 kWh. Ultimately, the primary energy saving was 12% and the daily operational cost was 2.9 €/day.

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Section: Campaign Results and Discussionsupporting

confidence: 89%

Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

et al. 2021

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“…Thermoelectric conversion is usually performed by means of heat engines, e.g., Stirling motors [36,37] or organic Rankine cycle [38] turbines, or by means of solid-state modules based on the Seebeck effect [39][40][41]. However, the thermoelectric energy production from low-and medium-temperature sources is an active research field, in which innovative solutions are studied (see, for example [42]).…”

Section: Introductionmentioning

confidence: 99%

Proof-of-Concept of a Zinc-Silver Battery for the Extraction of Energy from a Concentration Difference

et al. 2014

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The conversion of heat into current can be obtained by a process with two stages. In the first one, the heat is used for distilling a solution and obtaining two flows with different concentrations. In the second stage, the two flows are sent to an electrochemical cell that produces current by consuming the concentration difference. In this paper, we propose such an electrochemical cell, working with water solutions of zinc chloride. The cell contains two electrodes, made respectively of zinc and silver covered by silver chloride. The operation of the cell is analogous to that of the capacitive mixing and of the "mixing entropy battery": the electrodes are charged while dipped in the concentrated solution and discharged when dipped in the diluted solution. The cyclic operation allows us to extract a surplus of energy, at the expense of the free energy of the concentration difference. We evaluate the feasibility of such a cell for practical applications and find that a power up to 2 W per m 2 of the surface of the electrodes can be achieved.

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“…Lombardi et al [63] modified the mentioned model by adding a linear method to it. Ulloa et al [64] proposed a simple model of Whispergen DC PPS16-24MD engine running on diesel. Their work was carried on TRNSYS and was based on lumped-mass blocks and an optimized performance (GenOpt).…”

Section: Stirling Engine Modeling Approachesmentioning

confidence: 99%

Performance Analysis of a Stirling Engine Hybrid Power System

et al. 2020

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The Bolivian government’s concerns that are related to reducing the consumption of diesel fuel, which is imported, subsidized, and provided to isolated electric plants in rural communities, have led to the implementation of hybrid power systems. Therefore, this article presents the performance analysis in terms of energy efficiency, economic feasibility, and environmental sustainability of a photovoltaic (PV)/Stirling battery system. The analysis includes the dynamic start-up and cooling phases of the system, and then compares its performance with a hybrid photovoltaic (PV)/diesel/battery system, whose configuration is usually more common. Both systems were initially optimized in size using the well-known energy optimization software tool, HOMER. An estimated demand for a hypothetical case study of electrification for a rural village of 102 households, called “Tacuaral de Mattos”, was also considered. However, since the characteristics of the proposed systems required a detailed analysis of its dynamics, a dynamic model that complemented the HOMER analysis was developed using MATLAB Simulink TM 8.9. The results showed that the PV/Stirling battery system represented a higher performance option to implement in the electrification project, due to its good environmental sustainability (69% savings in CO2 emissions), economic criterion (11% savings in annualized total cost), and energy efficiency (5% savings in fuel energy conversion).

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

Cited by 22 publications

References 22 publications

Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

Proof-of-Concept of a Zinc-Silver Battery for the Extraction of Energy from a Concentration Difference

Performance Analysis of a Stirling Engine Hybrid Power System

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