scholarly journals Application of Stirling Engine Type Alpha Powered by the Recovery Energy on Vessels

2020 ◽  
Vol 27 (1) ◽  
pp. 96-106
Author(s):  
Jacek Kropiwnicki
Keyword(s):  
Thermal Energy ◽  
Mechanical Energy ◽  
Structural Features ◽  
Stirling Engine ◽  
Engine Simulation ◽  
Engine Room ◽  
Stirling Engines ◽  
Potential Applications ◽  
The Impact ◽  
Engine Type

AbstractThe Stirling engine is a device in which thermal energy is transformed into mechanical energy without any contact between the heat carrier and the working gas enclosed in the engine. The mentioned feature makes this type of engine very attractive for the use of the recovery energy taken from other heat devices. One of the potential applications of Stirling engines is the use of thermal energy generated in the ship’s engine room for producing electricity. The work presents the concept of the Stirling engine type alpha powered by the recovery energy. The model of Stirling engine developed in this work allows a quantitative assessment of the impact of the design features of the engine, primarily the heat exchange surfaces and the volume of control spaces, on the achieved efficiency and power of the engine. Using an iterative procedure, Stirling engine simulation tests were carried out taking into account the variable structural features of the system. The influence of the size of the heater and the cooler, as well as the effectiveness of the regenerator and the temperature of the heat source on the efficiency and power produced by the Stirling engine have been presented.

scholarly journals Application of Stirling engine for recovery energy from exhaust gas

2018 ◽  
Vol 19 (9) ◽  
pp. 89-92
Author(s):  
Jacek Kropiwnicki ◽  
Mariusz Furmanek
Keyword(s):  
Waste Heat ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Power Source ◽  
Stirling Engine ◽  
Flue Gases ◽  
Exhaust Gas ◽  
Stirling Engines ◽  
Waste Energy ◽  
Engine Type

Stirling engine is device generating mechanical energy without combustion fuel inside cylinder. This fact allows to supply engine from any power source. Example of such energy source can be solar radiation, combustion low-calorie carbon in outside combustion chamber or waste heat from other device like combustion engine mounted in bus or lorry. Use that kind of device in car allows to reduce fuel consumption through increase of efficiency of utilization thermal energy produced in combustion engine. The paper presents commercial solution of Stirling engines powered by waste energy and project of conceptual Stirling engine type alpha powered by flue gases from truck. The initial analysis results of hydraulic resistance in that engine have been also included.

Design Optimization of a Solar Dish Collector for Its Application With Stirling Engines

2015 ◽  
Author(s):  
Ana C. Ferreira ◽  
Senhorinha Teixeira ◽  
José C. Teixeira ◽  
Luís B. Martins
Keyword(s):  
Mathematical Model ◽  
Thermal Behavior ◽  
Solar Collector ◽  
High Efficiency ◽  
Mechanical Energy ◽  
Stirling Engine ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Aperture Diameter ◽  
Stirling Engines

Solar concentric dish collectors and Stirling engines with cavity receivers are commonly considered for this purpose due to the high efficiency for converting solar radiation into mechanical energy. The study and design of a solar collector of this type, and of its cavity receiver, require solving a mathematical model that take into account the geometric, optical and thermal behavior of all components. With an adequate sizing, not only the useful energy produced on the solar device will meet the energy required for the process, but also the absorber temperature will be the needed for the operation of the Stirling engine. This paper focuses on the construction of a mathematical model that represents the operational performance of a concentric solar dish with cavity receiver for its applications in Stirling engines. The purpose is to develop a designing tool for optimization and for quantifying the effect of changing the values of design parameters over any specific output behavior or the overall performance of the system. The parameters in the optimization include: geometrical variables, i.e., the solar dish diameter, the receiver aperture diameter or the focal length; and optical variables, i.e., rim and incident angles, and irradiation interception factor. The objective is to minimize the solar dish collector cost and calculate the heat available to the Stirling engine, contained in the receiver cavity, to be converted in to mechanical energy. The numerical model was coded in the MatLab® programming language. The results of the simulation disclosed a model able to predict, adequately, the optical and thermal behavior of the described system, so that the model can be used to study the operation and also to design parameters. The optimal results disclosed the configuration of a solar collector dish with a rim angle of about 41° and for a dish diameter of 6.58 m and an aperture receiver of 0.12 m for a minimum cost of 4717 €. It was also concluded that the maximum temperature reached in the absorber of a receiver cavity, is limited mainly by the geometric relationships between the dish diameter, receiver aperture diameter and the aperture ratio, and it is possible to obtain an ideal thermal efficiency of 64%.

scholarly journals A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1622 ◽  
Author(s):  
Jacek Kropiwnicki ◽  
Mariusz Furmanek
Keyword(s):  
High Efficiency ◽  
Waste Heat ◽  
Heating Temperature ◽  
Mechanical Energy ◽  
Stirling Engine ◽  
Moderate Temperature ◽  
Heat Sources ◽  
Stirling Engines ◽  
Charge Pressure ◽  
Further Development

The Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling engine powered by a moderate temperature source of heat. Obtained results enabled calibration of the evaluated theoretical model of the Stirling engine. The model of the engine has been subsequently used for the analysis of regenerator effectiveness influenced by the charge pressure and the heating temperature. Performed study allowed to determine further development directions of the prototype engine to improve its power and efficiency. As a result of optimization, worked out design will potentially increase the indicated efficiency up to 19.5% (5.5% prototype) and the indicated power up to 369 W (114 W prototype).

Stirling Engines Powered by Renewable Energy Sources

2016 ◽  
Vol 831 ◽  
pp. 263-269
Author(s):  
Jacek Kropiwnicki ◽  
Aleksandra Szewczyk
Keyword(s):  
Renewable Energy ◽  
Low Temperature ◽  
Electric Power ◽  
Mechanical Energy ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Stirling Engine ◽  
Working Fluid ◽  
Energy Sources ◽  
Stirling Engines

Stirling engine is a device that produces mechanical energy using heat from any source of energy, without the need of combustion of any fuel inside the device. Renewable energy sources, which are mostly low-temperature energy sources, can be used to produce mechanical and electrical energy in Stirling engines. The paper presents an overview of the existing prototype Stirling engines designed for using of low-temperature energy sources, including renewable energy sources. Commercial devices for electric power generation offered for use in home, usually do not exceed 1 kW. Using the Schmidt model, the analyze of influence of temperature working fluid in the expansion space (heater) on the efficiency and the electric power generated in the Stirling engine of alpha type has been presented in the paper.

Characterization of Thermal Energy Harvesting Using Pyroelectric Ceramics at Elevated Temperatures

2018 ◽  
Vol 5 (1-2) ◽  
pp. 3-10 ◽  
Author(s):  
Luis A. Chavez ◽  
Fabian O. Zayas Jimenez ◽  
Bethany R. Wilburn ◽  
Luis C. Delfin ◽  
Hoejin Kim ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Thermal Energy ◽  
Elevated Temperatures ◽  
Mechanical Energy ◽  
Piezoelectric Ceramics ◽  
Pyroelectric Coefficient ◽  
Maximum Value ◽  
Thermal Energy Harvesting ◽  
Temperature Ranges ◽  
The Impact

Abstract Energy harvesting has drawn increasing attention due to the fast development of wireless sensors and devices. Most research has been focused on mechanical energy harvesting using piezoelectric ceramics; however, little is known on their experimental capabilities to harvest thermal energy at different temperature ranges and the impact that the temperature range has on the energy conversion efficiency. Majority of piezoelectric ceramics are pyroelectric in nature thus enabling them to couple energy between thermal and electrical domains. This paper demonstrates the use of Lithium Niobate (LNB) as a thermal energy harvesting device for high temperature applications. A custom testing setup was developed to test the LNB sample temperatures up to 225 °C. Pyroelectric coefficient of the material was characterized at different temperature ranges. Pyroelectric coefficient was found to increase with temperature, with a maximum value of −196 μC·m−2 °C−1. Power output of the sample was also characterized in different temperature ranges. A maximum value of over 20.5 μW was found when cycling the sample between 75 °C and 100 °C. Meanwhile, a maximum value of 14.8 μW was found in the 125 °C to 150 °C range. Finally, a peak value of 255 nW was found when cycling the sample in the 200 °C to 225 °C range.

Assessing the effect of night ventilation on PCM performance in high-rise residential buildings

2019 ◽  
Vol 43 (3) ◽  
pp. 229-249 ◽  
Author(s):  
Shahrzad Soudian ◽  
Umberto Berardi
Keyword(s):  
Thermal Energy ◽  
Phase Change Materials ◽  
Positive Impact ◽  
Residential Buildings ◽  
Solidification Rate ◽  
Operative Temperature ◽  
High Rise ◽  
Ventilation Strategies ◽  
Night Ventilation ◽  
The Impact

This article investigates the possibility to enhance the use of latent heat thermal energy storage (LHTES) as an energy retrofit measure by night ventilation strategies. For this scope, phase change materials (PCMs) are integrated into wall and ceiling surfaces of high-rise residential buildings with highly glazed facades that experience high indoor diurnal temperatures. In particular, this article investigates the effect of night ventilation on the performance of the PCMs, namely, the daily discharge of the thermal energy stored by PCMs. Following previous experimental tests that have shown the efficacy of LHTES in temperate climates, a system comprising two PCM layers with melting temperatures selected for a year-around LHTES was considered. To quantify the effectiveness of different night ventilation strategies to enhance the potential of this composite PCM system, simulations in EnergyPlusTM were performed. The ventilation flow rate, set point temperature, and operation period were the main tested parameters. The performance of the PCMs in relation to the variables was evaluated based on indoor operative temperature and cooling energy use variations in Toronto and New York in the summer. The solidification of the PCMs was analyzed based on the amount of night ventilation needed in each climate condition. The results quantify the positive impact of combining PCMs with night ventilation on cooling energy reductions and operative temperature regulation of the following days. In particular, the results indicate higher benefits obtainable with PCMs coupled with night ventilation in the context of Toronto, since this city experiences higher daily temperature fluctuations. The impact of night ventilation design variables on the solidification rate of the PCMs varied based on each parameter leading to different compromises based on the PCM and climate characteristics.

Diarylethene Dyes

2020 ◽  
Vol 5 (7) ◽  
Author(s):  
Andrew Towns
Keyword(s):  
Structural Features ◽  
Photochromic Dye ◽  
Potential Applications

AbstractThis article introduces the general characteristics of the diarylethene class of photochromic dye and the structural features that make photochromism possible. It touches on the methodologies employed to synthesize these compounds as well as the influences that typical substitution patterns exert on photocoloration. A demonstration is then given of the great diversity pertaining to the potential applications in which researchers are seeking to exploit them as functional colorants.

scholarly journals Unusual Structural Features in the Adduct of Dirhodium Tetraacetate with Lysozyme

2021 ◽  
Vol 22 (3) ◽  
pp. 1496
Author(s):  
Domenico Loreto ◽  
Giarita Ferraro ◽  
Antonello Merlino
Keyword(s):  
Anticancer Agents ◽  
Structural Features ◽  
Side Chain ◽  
Side Chains ◽  
Valuable Insight ◽  
Experimental Conditions ◽  
Egg White Lysozyme ◽  
Potential Applications ◽  
Model Protein ◽  
Hen Egg White

The structures of the adducts formed upon reaction of the cytotoxic paddlewheel dirhodium complex [Rh2(μ-O2CCH3)4] with the model protein hen egg white lysozyme (HEWL) under different experimental conditions are reported. Results indicate that [Rh2(μ-O2CCH3)4] extensively reacts with HEWL:it in part breaks down, at variance with what happens in reactions with other proteins. A Rh center coordinates the side chains of Arg14 and His15. Dimeric Rh–Rh units with Rh–Rh distances between 2.3 and 2.5 Å are bound to the side chains of Asp18, Asp101, Asn93, and Lys96, while a dirhodium unit with a Rh–Rh distance of 3.2–3.4 Å binds the C-terminal carboxylate and the side chain of Lys13 at the interface between two symmetry-related molecules. An additional monometallic fragment binds the side chain of Lys33. These data, which are supported by replicated structural determinations, shed light on the reactivity of dirhodium tetracarboxylates with proteins, providing useful information for the design of new Rh-containing biomaterials with an array of potential applications in the field of catalysis or of medicinal chemistry and valuable insight into the mechanism of action of these potential anticancer agents.

scholarly journals Evaluating polymer interplay after hot water pretreatment to investigate maize stem internode recalcitrance

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Amandine Leroy ◽  
Xavier Falourd ◽  
Loïc Foucat ◽  
Valérie Méchin ◽  
Fabienne Guillon ◽  
...  
Keyword(s):  
Cell Wall ◽  
Negative Impact ◽  
Lignin Content ◽  
Structural Features ◽  
Hot Water ◽  
Condensed State ◽  
Structural Factors ◽  
Water Pretreatment ◽  
Hot Water Pretreatment ◽  
The Impact

Abstract Background Biomass recalcitrance is governed by various molecular and structural factors but the interplay between these multiscale factors remains unclear. In this study, hot water pretreatment (HWP) was applied to maize stem internodes to highlight the impact of the ultrastructure of the polymers and their interactions on the accessibility and recalcitrance of the lignocellulosic biomass. The impact of HWP was analysed at different scales, from the polymer ultrastructure or water mobility to the cell wall organisation by combining complementary compositional, spectral and NMR analyses. Results HWP increased the kinetics and yield of saccharification. Chemical characterisation showed that HWP altered cell wall composition with a loss of hemicelluloses (up to 45% in the 40-min HWP) and of ferulic acid cross-linking associated with lignin enrichment. The lignin structure was also altered (up to 35% reduction in β–O–4 bonds), associated with slight depolymerisation/repolymerisation depending on the length of treatment. The increase in $${T}_{1\rho }^{H}$$ T 1 ρ H , $${T}_{HH}$$ T HH and specific surface area (SSA) showed that the cellulose environment was looser after pretreatment. These changes were linked to the increased accessibility of more constrained water to the cellulose in the 5–15 nm pore size range. Conclusion The loss of hemicelluloses and changes in polymer structural features caused by HWP led to reorganisation of the lignocellulose matrix. These modifications increased the SSA and redistributed the water thereby increasing the accessibility of cellulases and enhancing hydrolysis. Interestingly, lignin content did not have a negative impact on enzymatic hydrolysis but a higher lignin condensed state appeared to promote saccharification. The environment and organisation of lignin is thus more important than its concentration in explaining cellulose accessibility. Elucidating the interactions between polymers is the key to understanding LB recalcitrance and to identifying the best severity conditions to optimise HWP in sustainable biorefineries.

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