Low Temperature Differential Stirling Engine Research Articles

Workshop of assembling low temperature differential Stirling engine in which positioning of cylinder and flat-shaped cylinder head by pins

The Low temperature differential Stirling engine for a craft workshop was improved. Fine adjustment during assembly is not necessary. Here, the explanation for attendees of a 5-hour-course craft workshop is shown by some pictures.

Polyethylene bellows for model low temperature differential Stirling engine

Polyethylene bellows for model low temperature differential Stirling engine

Operation of a low-temperature differential heat engine for power generation via hybrid nanogenerators

This work aims for the exploitation of low-grade thermal energy (<100 °C) in conjunction with the operation of nanogenerators run by a highly responsive low-temperature differential (LTD) heat engine. Two different types of nanogenerators were fabricated and tested in four different schemes: triboelectric in non-contact sliding mode (TENG), piezoelectric in contact-separation mode (PENG), triboelectric in contact-separation mode (TENG-2), and coupled triboelectric and piezoelectric in contact-separation mode (TENG-PENG). A series of tests were performed in generating power from the coupled action of triboelectric and piezoelectric nanogenerators with the operation of a LTD Stirling engine to harness low-grade thermal energy. This stands out as compared to previous studies from the perspective of operating two different types of nanogenerators in two different modes at the same time and the exploitation of low-grade thermal energy rather than the ambient mechanical energy, which is witnessed in most accomplishments in the relevant area. Running the triboelectric nanogenerator (non-contact sliding mode) with a small LTD heat engine (MM-7 Stirling engine) delivered a maximum output voltage of 35 V for a temperature difference of 73.2 °C. Meanwhile, the piezoelectric, triboelectric, and hybridized triboelectric-piezoelectric (contact-separation mode) nanogenerator produced output voltages of 4 V, 20.1 V, and 40 V, respectively. A maximum combined voltage of 74 V was also measured when the output of the triboelectric generator in noncontact sliding mode was combined with the hybrid (triboelectric-piezoelectric) nanogenerator operating in contact-separation mode. Operating the nanogenerators in conjunction with an electromagnetic generator (EMG) was also tested as appropriate, which clearly demonstrates the potential of their application in a hybrid manner if needed.

Dynamic analysis and demonstration of flywheel-less low temperature differential Stirling engine using bellows instead of power piston

Dynamic analysis and demonstration of flywheel-less low temperature differential Stirling engine using bellows instead of power piston

Thermodynamic Analysis of Solar Low-Temperature Differential Stirling Engine Considering Imperfect Regeneration and Thermal Losses

Abstract Low-temperature differential Stirling engines (LTDSE) are the gamma-type Stirling engines that can produce useful work from source temperatures less than 350 K, making them a preferred choice/device for solar energy utilization. An improved mathematical model to evaluate the performance of the solar-operated LTDSE has been developed by incorporating the top heat loss coefficient correlation with the finite-time thermodynamic model of the Stirling engine. In order to realize the internal imperfections of the thermodynamic Stirling cycle, the effect of the imperfect regeneration process is incorporated. Input parameters such as absorber plate temperature, irradiation, and geometrical features of the solar LTDSE are taken from real-time experimental data available in the literature. The effect of convective and radiation heat transfer coefficients of working fluid on maximum power output and thermal efficiency is determined to be significant and marginal, respectively. A comprehensive study of various working fluids and regenerator materials is carried out to investigate their impact on the performance of solar LTDSE. Helium is the best-working fluid, among air, hydrogen, ethane, and nitrogen for the considered model. Copper exhibited maximum regenerator effectiveness compared with Monel 400, aluminum, SS-304L.

Optimization of Low Temperature Differential Stirling Engine Regenerator Design

Optimization of Low Temperature Differential Stirling Engine Regenerator Design

Theoretical Analysis of Hybrid Dense-Array Concentrator Photovoltaic and Stirling Engine System

Abstract In this paper, we analyse the performance of newly proposed hybrid dense-array concentrator photovoltaic (CPV) and gamma type low temperature differential (LTD) Stirling engine. Schmidt Analysis was applied to compute the performance of LTD Stirling engine while computational fluid dynamic was employed to simulate the heat transfer in the CPV receiver. The simulated result was subsequently used to determine the power conversion efficiency of the hybrid system. Three major parameters have been considered to optimize the overall system performance including water inlet temperature, water flow rate, and CPV surface temperature. In our theoretical analysis, the highest efficiency of the hybrid system ranging 37.8 - 38.0 % can be achieved at water inlet temperature of 90°C. It has shown significant improvement by producing 10.1 -10.7 % extra energy as compared to the efficiency of CPV system without waste heat recovery.

Development of Stirling Pump mechanism for Irrigation in remote rural farms

Inadequate supply of safe water, the requirement of food exports, Low GDP creates a scenario where 26% of the population in the Sub-Saharan Africa suffer from food insecurity. Cultivation of food locally is necessary to drive the cost of food down. This can be done using the abundant groundwater source in the region, however, the energy cost of harvesting the water supply is very high and hence not presently utilised. While solar PV technology is readily available, PV solutions are much too expensive for small scale rural farmers. This research aims at developing a solar thermal powered Stirling pump that can be produced locally, using local resources to reduce irrigation costs and provide income, food and energy security in the region, by promoting independent farming through small-scale farms. In order to develop the Stirling pump, a Low Temperature Differential (LTD) Stirling engine has been modelled in 3D, simulated and investigated with the help of Computational Fluid Dynamics with ANSYS 16.1 software. The Analysis is aimed at obtaining a true representation of the pressure, temperature and compression ratio that dictate the functioning of a Gamma type Stirling engine. This model developed can then be modified and improved upon to further boost the performance of the Stirling Engine to be integrated with a water pumping system to extract ground water for irrigation purposes.

Workshop of assembling low temperature differential Stirling engine designed for craft workshop for 5 person who want to see the inside

Workshop of assembling low temperature differential Stirling engine designed for craft workshop for 5 person who want to see the inside

Dynamic analysis of low temperature differential Stirling engine using bellows instead of piston

Dynamic analysis of low temperature differential Stirling engine using bellows instead of piston

Proof of concept to recover thermal wastes from aluminum electrolysis cells using Stirling engines

The production of aluminum is a low energy-efficient industrial process. In fact, almost half of its energy demand is lost under the form of heat along the production line. For this reason, aluminum producers are interested in improving energy efficiency of their smelters by recovering the thermal losses. It is well known that a significant loss of energy occurs across the sidewalls of the electrolysis cells. This paper proposes a proof of concepts where the sidewall thermal wastes are used to drive Low Temperature Differential (LTD) Stirling engines. To estimate the losses, a heat transfer study is implemented; heat conduction coupled with mixed convection and radiation is evaluated by using the OpenFOAM Computational Fluid Dynamic (CFD) software. Then, a parametric study is performed to analyse cell working conditions under which thermal wastes could be recovered. The heat flux and the temperature of the thermal wastes are used to judge the utilization of possible Stirling engine technologies. Two scenarios are studied: (i) a plane heat collector coupled to the radiative sidewall and (ii) a plane heat collector in direct thermal contact with the cell sidewall. It is demonstrated that the recovery of the wastes by radiation is technically feasible and it does not threaten the safety of the smelter; furthermore, the losses can power some Stirling engines given in the open literature. Therefore, the recovery of the radiative wastes and the further conversion by means of the Stirling engine is an interesting solution to improve the aluminium smelter energy efficiency.

An engine speed estimation of a low temperature differential Stirling engine using Microsoft Excel

An engine speed estimation of a low temperature differential Stirling engine using Microsoft Excel

Design and Fabrication of Low Temperature Differential Stirling Engine - Gamma Type

Design and Fabrication of Low Temperature Differential Stirling Engine - Gamma Type

Parts designs of low temperature differential Stirling engines relieving the assembly of fine adjustments

Parts designs of low temperature differential Stirling engines relieving the assembly of fine adjustments

Workshop of assembling low temperature differential Stirling engine for 5 person who want to see the inside

Workshop of assembling low temperature differential Stirling engine for 5 person who want to see the inside

Design of stirling engine operating at low temperature difference

There are many sources of free energy available in the form of heat that is often simply wasted. The aim of this paper is to design and build a low temperature differential Stirling engine that would be powered exclusively from heat sources such as waste hot water or focused solar rays. A prototype is limited to a low temperature differential modification because of a choice of ABSplus plastic as a construction material for its key parts. The paper is divided into two parts. The first part covers a brief history of Stirling engine and its applications nowadays. Moreover, it describes basic principles of its operation that are supplemented by thermodynamic relations. Furthermore, an analysis of applied Fused Deposition Modelling has been done since the parts with more complex geometry had been manufactured using this additive technology. The second (experimental) part covers 4 essential steps of a rapid prototyping method - Computer Aided Design of the 3D model of Stirling engine using parametric modeller Autodesk Inventor, production of its components using 3D printer uPrint, assembly and final testing. Special attention was devoted to last two steps of the process since the surfaces of the printed parts were sandpapered and sprayed. Parts, where an ABS plus plastic would have impeded the correct function, had been manufactured from aluminium and brass by cutting operations. Remaining parts had been bought in a hardware store as it would be uneconomical and unreasonable to manufacture them. Last two chapters of the paper describe final testing, mention the problems that appeared during its production and propose new approaches that could be used in the future to improve the project.

Thermodynamics Analysis for Optimal Geometrical Parameters and Influence of Heat Sink Temperature of Gamma-configuration Stirling Engine

Abstract This paper provides theoretical predictions on the thermodynamic analysis of a low-temperature differential (LTD) Stirling engine. A twin power piston, gamma-configuration, LTD Stirling engine is considered with a heat source temperature of 353 K and heat sink temperature of 307 K. Second-order thermodynamic models are performed with MATLAB software. The geometrical parameters investigated include the power piston stroke, the displacer stroke, the displacer diameter, and the displacer thickness. Results from this study indicate that the indicated power density is achieved at a fixed 4 RPM engine. This engine has geometrical parameters with a power piston stroke of 0.29 m, displacer stroke of 0.21 m, displacer diameter of 1.44 m, and displacer thickness of 0.26 m. Additionally, the effects of the heat sink temperature on the indicated power output is performed and analyzed. The result shows that the indicated power output increased with a decreasing heat sink temperature.

Workshop of assembling low temperature differential Stirling engine version 2017

Workshop of assembling low temperature differential Stirling engine version 2017

Operation of Low temperature differential Stirling engine competition and presentations

Operation of Low temperature differential Stirling engine competition and presentations

A low temperature differential Stirling engine design relieving the assembly of a fine adjustment

A low temperature differential Stirling engine design relieving the assembly of a fine adjustment