On the maximum efficiency of the ideal regenerative stirling cycle

2010 ◽  
Vol 45 (3) ◽  
pp. 137-139 ◽  
Author(s):  
R. M. Abrahamian
Keyword(s):  
Maximum Efficiency ◽  
Stirling Cycle ◽  
The Ideal

scholarly journals Cyclic Control Optimization Algorithm for Stirling Engines

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 873
Author(s):  
Raphael Paul ◽  
Karl Heinz Hoffmann
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Limit Cycles ◽  
Stirling Engine ◽  
Maximum Power ◽  
Maximum Efficiency ◽  
Engine Model ◽  
Stirling Engines ◽  
The Ideal

The ideal Stirling cycle describes a specific way to operate an equilibrium Stirling engine. This cycle consists of two isothermal and two isochoric strokes. For non-equilibrium Stirling engines, which may feature various irreversibilities and whose dynamics is characterized by a set of coupled ordinary differential equations, a control strategy that is based on the ideal cycle will not necessarily yield the best performance—for example, it will not generally lead to maximum power. In this paper, we present a method to optimize the engine’s piston paths for different objectives; in particular, power and efficiency. Here, the focus is on an indirect iterative gradient algorithm that we use to solve the cyclic optimal control problem. The cyclic optimal control problem leads to a Hamiltonian system that features a symmetry between its state and costate subproblems. The symmetry manifests itself in the existence of mutually related attractive and repulsive limit cycles. Our algorithm exploits these limit cycles to solve the state and costate problems with periodic boundary conditions. A description of the algorithm is provided and it is explained how the control can be embedded in the system dynamics. Moreover, the optimization results obtained for an exemplary Stirling engine model are discussed. For this Stirling engine model, a comparison of the optimized piston paths against harmonic piston paths shows significant gains in both power and efficiency. At the maximum power point, the relative power gain due to the power-optimal control is ca. 28%, whereas the relative efficiency gain due to the efficiency-optimal control at the maximum efficiency point is ca. 10%.

scholarly journals Analisa Isolasi Pipa Generator Mesin Stirling Tipe Alpha Sudut Fasa 180°

2021 ◽  
Vol 6 (1) ◽  
pp. 1-7
Author(s):  
Dhimas Satria ◽  
Rina Lusiani ◽  
Erny Listijorini ◽  
Aswata
Keyword(s):  
Heat Loss ◽  
Phase Angle ◽  
Stirling Engine ◽  
Compression Process ◽  
Stirling Cycle ◽  
Compression Speed ◽  
Stirling Engines ◽  
Pipe Insulation ◽  
Alpha Type ◽  
The Ideal

This research is a development of previous research, where in the previous research, a design innovation was carried out on an alpha-type stirling engine by making the phase angle to 180o, with the aim of reducing the effect when the cold cylinder is compressed, because the phase angle currently used is (90o) with disadvantages, namely the cold cylinder is perpendicular to the top, so that the compression process against gravity. But in previous studies, the generator pipe was too long, causing a lot of energy or heat loss (heat loss) so that the compression speed was small. So that in the research, innovated and analyzed the pipe insulation of alpha-type stirling engine generators, alpha-type stirling engines, 180o phase angle. The research method used is to use the thermodynamic approach with Schmidt theory and the theory of the ideal cycle stirling engine. while the simulation is done using the Ideal Stirling Cycle Calculator. Results investigated shows that providing insulation on the generator pipes of an alpha-type stirling engine for an alpha-type stirling engine with a 180o phase angle is proven to reduce a lot of energy or heat loss (heat loss) due to too long generator pipes, with a heat loss value ratio of 226.66 W for the pipe. generator that uses insulation whose value is smaller than the value of the heat loss when the generator pipe without using isocation is 1,584.12 W.

scholarly journals Non-commutative space engine: A boost to thermodynamic processes

2021 ◽  
Vol 36 (24) ◽  
pp. 2150174
Author(s):  
Tanmoy Pandit ◽  
Pritam Chattopadhyay ◽  
Goutam Paul
Keyword(s):  
Phase Space ◽  
Catalytic Effect ◽  
Otto Cycle ◽  
Stirling Cycle ◽  
Heat Engines ◽  
Working Medium ◽  
Commutative Space ◽  
Thermodynamic Variables ◽  
Thermodynamic Processes ◽  
The Ideal

We introduce quantum heat engines that perform quantum Otto cycle and the quantum Stirling cycle by using a coupled pair of harmonic oscillator as its working substance. In the quantum regime, different working medium is considered for the analysis of the engine models to boost the efficiency of the cycles. In this work, we present Otto and Stirling cycle in the quantum realm where the phase space is non-commutative in nature. By using the notion of quantum thermodynamics, we develop the thermodynamic variables in non-commutative phase space. We encounter a catalytic effect (boost) on the efficiency of the engine in non-commutative space (i.e. we encounter that the Stirling cycle reaches near to the efficiency of the ideal cycle) when compared with the commutative space. Moreover, we obtained a notion that the working medium is much more effective for the analysis of the Stirling cycle than that of the Otto cycle.

scholarly journals Idealization of The Real Stirling Cycle

2016 ◽  
Vol 14 (3) ◽  
pp. 19-27 ◽  
Author(s):  
Libor Červenka
Keyword(s):  
Simulation Model ◽  
Simulation Software ◽  
Stirling Engine ◽  
The Real ◽  
Stirling Cycle ◽  
The Ideal

Abstract The paper presents a potential idealization of the real Stirling cycle. This idealization is performed by modifying the piston movement corresponding to the ideal Stirling cycle. The focus is on the cycle thermodynamics with respect to the indicated efficiency and indicated power. A detailed 1-D simulation model of a Stirling engine is used as a tool for this assessment. The model includes real non-zero volumes of heater, regenerator, cooler and connecting pipe. The model is created in the GT Power commercial simulation software.

Fluid Particle Trajectories in Stirling-Cycle Machines

1978 ◽  
Vol 20 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. J. Organ
Keyword(s):  
Particle Trajectory ◽  
Fluid Particle ◽  
Working Fluid ◽  
Piston Motion ◽  
Stirling Cycle ◽  
Working Space ◽  
Specific Entropy ◽  
Set Up ◽  
Limiting Case ◽  
The Ideal

Equations are set up by means of which arbitrarily selected particles of working fluid may be ‘tracked’ continuously throughout a cycle. Pressure is assumed to be instantaneously uniform, but account is taken of variable working space temperatures. Fluid particle trajectory maps are presented for machines of two types. One has opposed pistons following the ‘ideal’, discontinuous motion. The other has coaxial piston and displacer actuated by the rhombic drive mechanism. For the limiting case of isothermal phases, pressure is plotted against specific volume, and temperature against specific entropy for selected tracked particles. Thus it is deduced that, even when the unswept volume is taken to be zero, and piston motion to be discontinuous, it is not possible to draw either a unique p-v diagram or a unique t-s diagram for any practical embodiment of the Stirling cycle. It is demonstrated that such relationships may be viewed instead as summations of an infinity of p-vs or t-s relationships, that is, one for each discrete working fluid element.

scholarly journals INVESTIGATION PERFORMANCE OF PICO HYDRO WATER PIPE TURBINE

2021 ◽  
Vol 2 (3) ◽  
pp. 051-058
Author(s):  
Marwani Marwani ◽  
Muhammad Zahri Kadir ◽  
Ronny Egetha Putra
Keyword(s):  
Electrical Energy ◽  
Maximum Efficiency ◽  
Water Pipe ◽  
Small Power ◽  
Flow Discharge ◽  
Hydro Turbine ◽  
Turbine Performance ◽  
Water Turbines ◽  
Hydro Turbines ◽  
The Ideal

The flow of water in the pipeline for household needs is a source of energy that can generate electrical energy through Pico hydro turbines or small-power water turbines. The experiment has been conducted on a 10 Watt Pico hydro turbine mounted on a water pipe against changes in water flow discharge. The turbine performance analysis is conducted experimentally (actual) and theoretically (ideal). The analysis results showed the greater the discharge flow, the greater the power generated by the turbine. In tests with a maximum discharge of 8.9 l/min, the actual power of 1.121 Watts, the torque of 0.005 Nm with a rotation speed of 2146.8 rpm and efficiency of 12.59%; while the ideal power is based on Euler turbine equation of 4.2 Watts and torque of 0.016 Nm. So, the maximum turbine power that can be generated is only 26.67% ideal. Efficiency turbine decreases with increased discharge; in this test, the maximum efficiency was 24.89% at 5.8 L/min flow discharge.

Evaluation of a second order simulation for Sterling engine design and optimisation

2010 ◽  
Vol 21 (2) ◽  
pp. 17-29 ◽  
Author(s):  
Johannes M. Strauss ◽  
Robert T. Dobson
Keyword(s):  
Engine Performance ◽  
Second Order ◽  
Simulation Tool ◽  
Simulation Accuracy ◽  
Stirling Cycle ◽  
Cycle Simulation ◽  
Alternative Method ◽  
Engine Design ◽  
Operational Variables ◽  
The Ideal

This paper reports on the investigation of the simulation accuracy of a second order Stirling cycle simulation tool as developed by Urieli (2001) and improvements thereof against the known performance of the GPU-3 Stirling engine. The objective of this investigation is to establish a simulation tool to perform preliminary engine design and optimisation.The second order formulation under investigation simulates the engine based on the ideal adiabatic cycle, and parasitic losses are only accounted for afterwards. This approach differs from third order formulations that simulate the engine in a coupled manner incorporating non-idealities during cyclic simulation. While the second order approach is less accurate, it holds the advantage that the degradation of the ideal performance due to the various losses is more clearly defined and offers insight into improving engine performance. It is therefore particularly suitable for preliminary design of engines.Two methods to calculate the performance and efficiency of the data obtained from the ideal adiabatic cycle and the parasitic losses were applied, namely the method used by Urieli and a proposed alternative method. These two methods differ essentially in how the regenerator and pumping losses are accounted for.The overall accuracy of the simulations, especially using the proposed alternative method to calculate the different operational variables, proved to be satisfactory. Although significant inaccuracies occurred for some of the operational variables, the simulated trends in general followed the measurements and it is concluded that this second order Stirling cycle simulation tool using the proposed alternative method to calculate the different operational variables is suitable for preliminary engine design and optimisation.

scholarly journals Economic Cycles of Carnot Type

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1344
Author(s):  
Constantin Udriste ◽  
Vladimir Golubyatnikov ◽  
Ionel Tevy
Keyword(s):  
Van Der Waals ◽  
Thermodynamic Cycle ◽  
Ideal Gas ◽  
Maximum Efficiency ◽  
Carnot Cycle ◽  
Refrigeration System ◽  
Classical Thermodynamic ◽  
Economic Cycles ◽  
Van Der Waals Surface ◽  
The Ideal

Originally, the Carnot cycle was a theoretical thermodynamic cycle that provided an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system. The first aim of this paper is to introduce and study the economic Carnot cycles concerning Roegenian economics, using our thermodynamic–economic dictionary. These cycles are described in both a Q−P diagram and a E−I diagram. An economic Carnot cycle has a maximum efficiency for a reversible economic “engine”. Three problems together with their solutions clarify the meaning of the economic Carnot cycle, in our context. Then we transform the ideal gas theory into the ideal income theory. The second aim is to analyze the economic Van der Waals equation, showing that the diffeomorphic-invariant information about the Van der Waals surface can be obtained by examining a cuspidal potential.

scholarly journals Stirling Thermodynamics using Phasor Notation

2021 ◽  
Vol 313 ◽  
pp. 12003
Author(s):  
David M. Berchowitz
Keyword(s):  
Pressure Ratio ◽  
Simple Cycle ◽  
Dead Volume ◽  
Pressure Amplitude ◽  
Stirling Cycle ◽  
Mean Pressure ◽  
The Mean ◽  
The Ideal

Phasor mathematics is used to develop the isothermal Stirling cycle and extended to the ideal adiabatic Stirling cycle. The results are developed for piston – piston (alpha) machines and displacer – piston (beta and gamma) machines. The effect of non-ideal regeneration is handled by defining a regenerator effectiveness ratio. The importance of the amplitude pressure ratio (pressure amplitude to the mean pressure) is developed and shown to be a useful parameter when evaluating the effect of dead volume or when applying simple cycle analyses. The analysis is developed for both power producing and cooling engines. The utility of these analyses is discussed with respect to calibrated results of real machines.

Localization of Intracellular Antigens in thin Sections with Ferritin Labeled Antibody

1970 ◽  
Vol 28 ◽  
pp. 174-175
Author(s):  
M.S. Shahrabadi ◽  
T. Yamamoto
Keyword(s):  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Antigenic Determinants ◽  
Conjugate Prior ◽  
Thin Sections ◽  
Specific Attachment ◽  
Intracellular Antigen ◽  
Antigen Antibody ◽  
Ideal Method ◽  
The Ideal

The technique of labeling of macromolecules with ferritin conjugated antibody has been successfully used for extracellular antigen by means of staining the specimen with conjugate prior to fixation and embedding. However, the ideal method to determine the location of intracellular antigen would be to do the antigen-antibody reaction in thin sections. This technique contains inherent problems such as the destruction of antigenic determinants during fixation or embedding and the non-specific attachment of conjugate to the embedding media. Certain embedding media such as polyampholytes (2) or cross-linked bovine serum albumin (3) have been introduced to overcome some of these problems.

Sign in / Sign up

Export Citation Format

Share Document