Comparison of the Net Work Output Between Stirling and Ericsson Cycles
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Recording and Evaluating the Pv Diagram with CASSY
LD Heat Physics Thermodynamic cycle Leaflets P2.6.2.4 Hot-air engine: quantitative experiments The hot-air engine as a heat engine: Recording and evaluating the pV diagram with CASSY Objects of the experiment Recording the pV diagram for different heating voltages. Determining the mechanical work per revolution from the enclosed area. Principles The cycle of a heat engine is frequently represented as a closed curve in a pV diagram (p: pressure, V: volume). Here the mechanical work taken from the system is given by the en- closed area: W = − ͛ p ⋅ dV (I) The cycle of the hot-air engine is often described in an idealised form as a Stirling cycle (see Fig. 1), i.e., a succession of isochoric heating (a), isothermal expansion (b), isochoric cooling (c) and isothermal compression (d). This description, however, is a rough approximation because the working piston moves sinusoidally and therefore an isochoric change of state cannot be expected. In this experiment, the pV diagram is recorded with the computer-assisted data acquisition system CASSY for comparison with the real behaviour of the hot-air engine. A pressure sensor measures the pressure p in the cylinder and a displacement sensor measures the position s of the working piston, from which the volume V is calculated. The measured values are immediately displayed on the monitor in a pV diagram. Fig. 1 pV diagram of the Stirling cycle 0210-Wei 1 P2.6.2.4 LD Physics Leaflets Setup Apparatus The experimental setup is illustrated in Fig. 2. 1 hot-air engine . 388 182 1 U-core with yoke . -
Novel Hot Air Engine and Its Mathematical Model – Experimental Measurements and Numerical Analysis
POLLACK PERIODICA An International Journal for Engineering and Information Sciences DOI: 10.1556/606.2019.14.1.5 Vol. 14, No. 1, pp. 47–58 (2019) www.akademiai.com NOVEL HOT AIR ENGINE AND ITS MATHEMATICAL MODEL – EXPERIMENTAL MEASUREMENTS AND NUMERICAL ANALYSIS 1 Gyula KRAMER, 2 Gabor SZEPESI *, 3 Zoltán SIMÉNFALVI 1,2,3 Department of Chemical Machinery, Institute of Energy and Chemical Machinery University of Miskolc, Miskolc-Egyetemváros 3515, Hungary e-mail: [email protected], [email protected], [email protected] Received 11 December 2017; accepted 25 June 2018 Abstract: In the relevant literature there are many types of heat engines. One of those is the group of the so called hot air engines. This paper introduces their world, also introduces the new kind of machine that was developed and built at Department of Chemical Machinery, Institute of Energy and Chemical Machinery, University of Miskolc. Emphasizing the novelty of construction and the working principle are explained. Also the mathematical model of this new engine was prepared and compared to the real model of engine. Keywords: Hot, Air, Engine, Mathematical model 1. Introduction There are three types of volumetric heat engines: the internal combustion engines; steam engines; and hot air engines. The first one is well known, because it is on zenith nowadays. The steam machines are also well known, because their time has just passed, even the elder ones could see those in use. But the hot air engines are forgotten. Our aim is to consider that one. The history of hot air engines is 200 years old. -
Arxiv:2003.07157V1 [Cond-Mat.Stat-Mech] 10 Mar 2020 Oin Ti on Htteiiilvlmso H Odadho Engine
Stirling engine operating at low temperature difference Alejandro Romanelli∗ Instituto de F´ısica, Facultad de Ingenier´ıa Universidad de la Rep´ublica C.C. 30, C.P. 11000, Montevideo, Uruguay (Dated: March 17, 2020) Abstract The paper develops the dynamics and thermodynamics of Stirling engines that run with tem- perature differences below 100 0C. The working gas pressure is analytically expressed using an alternative thermodynamic cycle. The shaft dynamics is studied using its rotational equation of motion. It is found that the initial volumes of the cold and hot working gas play a non-negligible role in the functioning of the engine. arXiv:2003.07157v1 [cond-mat.stat-mech] 10 Mar 2020 1 I. INTRODUCTION In the field of energy efficiency, the use of waste energy is one of the keys to improve the performance of facilities, whether industrial or domestic. In general the waste energy arises as heat, from some thermal process, that it is necessary to remove. Therefore the use of the waste energy is usually conditioned by the difficulty of converting heat into other forms of energy.1,2 The Stirling engines, being external combustion machines, have the potential to take advantage of any source of thermal energy to convert it into mechanical energy. This makes them candidates to be used in heat recovery systems. The Stirling engine is essentially a two-part hot-air engine which operates in a closed regenerative thermodynamic cycle, with cyclic compressions and expansions of the working fluid at different temperature levels.3,4 The flow of the working fluid is controlled only by the internal volume changes; there are no valves and there is a net conversion of heat into work or vice-versa. -
Cryogenic Refrigeration Using an Acoustic Stirling Expander
CRYOGENIC REFRIGERATION USING AN ACOUSTIC STIRLING EXPANDER Masters Thesis by Nick Emery Department of Mechanical Engineering, University of Canterbury Christchurch, New Zealand Abstract A single-stage pulse tube cryocooler was designed and fabricated to provide cooling at 50 K for a high temperature superconducting (HTS) magnet, with a nominal electrical input frequency of 50 Hz and a maximum mean helium working gas pressure of 2.5 MPa. Sage software was used for the thermodynamic design of the pulse tube, with an initially predicted 30 W of cooling power at 50 K, and an input indicated power of 1800 W. Sage was found to be a useful tool for the design, and although not perfect, some correlation was established. The fabricated pulse tube was closely coupled to a metallic diaphragm pressure wave generator (PWG) with a 60 ml swept volume. The pulse tube achieved a lowest no-load temperature of 55 K and provided 46 W of cooling power at 77 K with a p-V input power of 675 W, which corresponded to 19.5% of Carnot COP. Recommendations included achieving the specified displacement from the PWG under the higher gas pressures, design and development of a more practical co-axial pulse tube and a multi-stage configuration to achieve the power at lower temperatures required by HTS. ii Acknowledgements The author acknowledges: His employer, Industrial Research Ltd (IRL), New Zealand, for the continued support of this work, Alan Caughley for all his encouragement, help and guidance, New Zealand’s Foundation for Research, Science and Technology for funding, University of Canterbury – in particular Alan Tucker and Michael Gschwendtner for their excellent supervision and helpful input, David Gedeon for his Sage software and great support, Mace Engineering for their manufacturing assistance, my wife Robyn for her support, and HTS-110 for creating an opportunity and pathway for the commercialisation of the device. -
Chapter 9, Problem 16. an Air-Standard Cycle Is Executed in A
COSMOS: Complete Online Solutions Manual Organization System Chapter 9, Problem 16. An air-standard cycle is executed in a closed system and is composed of the following four processes: 1-2 Isentropic compression from 100 kPa and 27°C to 1 MPa 2-3 P = constant heat addition in amount of 2800 kJ/kg 3-4 v = constant heat rejection to 100 kPa 4-1 P = constant heat rejection to initial state (a) Show the cycle on P-v and T-s diagrams. (b) Calculate the maximum temperature in the cycle. (c) Determine the thermal efficiency. Assume constant specific heats at room temperature. * Problems designated by a “C” are concept questions, and students are encouraged to answer them all. Problems designated by an “E” are in English units, and the SI users can ignore them. Problems with the are solved using EES, and complete solutions together with parametric studies are included on the enclosed DVD. Problems with the are comprehensive in nature and are intended to be solved with a computer, preferably using the EES software that accompanies this text. Thermodynamics: An Engineering Approach, 5/e, Yunus Çengel and Michael Boles, © 2006 The McGraw-Hill Companies. COSMOS: Complete Online Solutions Manual Organization System Chapter 9, Problem 37. The compression ratio of an air-standard Otto cycle is 9.5. Prior to the isentropic compression process, the air is at 100 kPa, 35°C, and 600 cm3. The temperature at the end of the isentropic expansion process is 800 K. Using specific heat values at room temperature, determine (a) the highest temperature and pressure in the cycle; (b) the amount of heat transferred in, in kJ; (c) the thermal efficiency; and (d) the mean effective pressure. -
Gamma-Type Stirling Engine Prototype
MODELLING AND OPTIMIZATION OF HIGH TEMPERATURE DIFFERENCE (HTD) GAMMA- TYPE STIRLING ENGINE PROTOTYPE By Suliman Alfarawi A thesis submitted to the University of Birmingham for the Degree of Doctor of Philosophy School of Mechanical Engineering College of Engineering and Physical Sciences The University of Birmingham September - 2017 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. ABSTRACT Finding solutions for increasing energy demands is being globally pursued. One of the promising solutions is the utilization of renewable forms of energy with thermo-mechanical conversion systems such as Stirling engines. Nowadays, effort is made in industry and academia to promote the development of Stirling technology. In this context, this thesis was first focused on modelling of High Temperature Difference (HTD) gamma-type Stirling engine prototype (ST05-CNC) and investigating means of improving its performance. Secondly, newly parallel- geometry mini-channel regenerators (with hydraulic diameters of 0.5, 1, 1.5 mm) and their test facility were developed and fabricated to enhance engine performance. Both thermodynamic and CFD models were comprehensively developed to simulate the engine and have been successfully validated against experimental data. -
Stirling Engine)
Heat Cycles Hot air engine (Stirling engine) OPERATE A FUNCTIONAL MODEL OF A STIRLING ENGINE AS A HEAT ENGINE Operate the hot-air engine as a heat engine Demonstrate how thermal energy is converted into mechanical energy Measure the no-load speed as a function of the thermal power UE2060100 04/16 JS BASIC PRINCIPLES The thermodynamic cycle of the Stirling engine While the working piston is in its top dead centre posi- (invented by Rev. R. Stirling in 1816) can be pre- tion: the displacement piston retracts and air is dis- sented in a simplified manner as the processes placed towards the top end of the large cylinder so that thermal input, expansion, thermal output and com- it cools. pression. These processes have been illustrated by The cooled air is compressed by the working piston schematic diagrams (Fig. 1 to Fig. 4) for the func- extending. The mechanical work required for this is tional model used in the experiment. provided by the flywheel rod. A displacement piston P1 moves upwards and displac- If the Stirling engine is operated without any mechanical es the air downwards into the heated area of the large load, it operates with at a speed which is limited only by cylinder, thereby facilitating the input of air. During this internal friction and which depends on the input heating operation the working piston is at its bottom dead centre energy. The speed is reduced as soon as a load takes position since the displacement piston is ahead of the up some of the mechanical energy. This is most easily working piston by 90°. -
In-Cylinder Heat Transfer in an Ericsson Engine Prototype
International Conference on Renewable Energies and Power Quality (ICREPQ’13) Bilbao (Spain), 20th to 22th March, 2013 exÇxãtuÄx XÇxÜzç tÇw cÉãxÜ dâtÄ|àç ]ÉâÜÇtÄ (RE&PQJ) ISSN 2172-038 X, No.11, March 2013 In-Cylinder Heat Transfer in an Ericsson Engine Prototype A. FULA 1,2, P. STOUFFS 1 and F.SIERRA2 1 Laboratoire de Thermique, Energétique et Procédés Université de Pau et des Pays de l´Adour 64000, Pau, France. e-mail: [email protected] 2 Facultad de Ingenieria – Laboratorio Máquinas Térmicas y Energias Renovables Universidad Nacional de Colombia - Carrera 30 No 45 a 03 Edificio 401, Bogotá, Colombia. Phone 3165000 xt 11130, e-mail: [email protected] [email protected] Abstract. An Ericsson engine is an external heat supply Qh Qc engine working according to a Joule thermodynamic cycle. It is based on reciprocating piston-cylinder machines. Such engines are especially interesting for low power solar energy conversion and micro-CHP from conventional fossil fuels or from biomass. H RK An Ericsson engine prototype has been designed and realized. Due to the geometrical configuration of the compression space of this prototype, in-cylinder fluid wall heat transfer can be important. The influence of this heat transfer on the engine performance is modelled and the main results are presented. E C The experimental setup designed to study the in-cylinder heat Fig. 1. Principle of the Stirling engine. transfer is presented. Q Key words K c Solar energy conversion, biomass energy conversion, H R Ericsson engine, hot air engines, distributed generation, cylinder wall heat transfer. -
HOT AIR ENGINE, DEVELOPED and PATENTED by TRAIAN VUIA, a ROMANIAN PERFORMANCE for 21St CENTURY
HOT AIR ENGINE, DEVELOPED AND PATENTED BY TRAIAN VUIA, A ROMANIAN PERFORMANCE FOR 21st CENTURY DUMITRU MIHALCEA1 Abstract. After thoroughly researching data from national archives, libraries, and important technical studies from Romania and abroad, I concluded that the hot air and closed-circuit engine built, tested, and patented by Romanian engineer Traian Vuia (1872–1950), is superior in its thermodynamic performances to similar engines investigated today. For this engine, almost as perfect thermodynamic Carnot engine, Traian Vuia has achieved ten (10) patents, during 1908-1916 years. Therefore, this engine unjustified forgotten or ignored over a century should be considered a wealth, which belongs (inter) national technical heritage. It represents a great challenge to bring this engine back to the scientific and industrial circuit and, in order to do so, this paper clarifies the following issues: • How evolved over time thermal cycling of different engines, as target perfect thermodynamic engine Carnot; • Which was the thermal process used at Vuia engine for isothermation of compression and expansion; • Today “isodiabate heat release and receipt” at Vuia engine can be qualified as an isentropic process for ideal conditions or adiabatic process for real conditions, with irreversibility, or others; • Which device used Traian Vuia for “isodiabate heat release and receipt”; • Which is the construction and operation of Vuia engine; • If thermal cycle and engine Vuia has been recognized internationally. Key words: Carnot, Stirling, Ericsson, Joule, Brayton, engines, almost perfect thermo- dynamic engines Vuia and Pomojnicu, engines with external combustion, isothermate compression and expansion, isentropic, adiabatic, isodiabatic heat release and receipt, regenerator, recuperator. 1. INTRODUCTION At a time when the steam engine showed signs of technical ageing, causing numerous accidents due to explosion of boilers and high consumption of coal, experts turned their attention to regenerative engines with open or closed circuits, 1Corresponding address: str. -
Beta Type Stirling Engine. Schmidt and Finite Physical Dimensions Thermodynamics Methods Faced to Experiments
entropy Article Beta Type Stirling Engine. Schmidt and Finite Physical Dimensions Thermodynamics Methods Faced to Experiments Cătălina Dobre 1 , Lavinia Grosu 2, Monica Costea 1 and Mihaela Constantin 1,* 1 Department of Engineering Thermodynamics, Engines, Thermal and Refrigeration Equipments, University Politehnica of Bucharest, Splaiul Independent, ei 313, 060042 Bucharest, Romania; [email protected] (C.D.); [email protected] (M.C.) 2 Laboratory of Energy, Mechanics and Electromagnetic, Paris West Nanterre La Défense University, 50, Rue de Sèvres, 92410 Ville d’Avray, France; [email protected] * Correspondence: [email protected] Received: 10 September 2020; Accepted: 9 November 2020; Published: 11 November 2020 Abstract: The paper presents experimental tests and theoretical studies of a Stirling engine cycle applied to a β-type machine. The finite physical dimension thermodynamics (FPDT) method and 0D modeling by the imperfectly regenerated Schmidt model are used to develop analytical models for the Stirling engine cycle. The purpose of this study is to show that two simple models that take into account only the irreversibility due to temperature difference in the heat exchangers and imperfect regeneration are able to indicate engine behavior. The share of energy loss for each is determined using these two models as well as the experimental results of a particular engine. The energies exchanged by the working gas are expressed according to the practical parameters, which are necessary for the engineer during the entire project, namely the maximum pressure, the maximum volume, the compression ratio, the temperature of the heat sources, etc. The numerical model allows for evaluation of the energy processes according to the angle of the crankshaft (kinematic–thermodynamic coupling). -
A Novel Thermomechanical Energy Conversion Cycle ⇑ Ian M
Applied Energy 126 (2014) 78–89 Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy A novel thermomechanical energy conversion cycle ⇑ Ian M. McKinley, Felix Y. Lee, Laurent Pilon Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, Los Angeles, CA 90095, USA highlights Demonstration of a novel cycle converting thermal and mechanical energy directly into electrical energy. The new cycle is adaptable to changing thermal and mechanical conditions. The new cycle can generate electrical power at temperatures below those of other pyroelectric power cycles. The new cycle can generate larger electrical power than traditional mechanical cycles using piezoelectric materials. article info abstract Article history: This paper presents a new power cycle for direct conversion of thermomechanical energy into electrical Received 21 May 2013 energy performed on pyroelectric materials. It consists sequentially of (i) an isothermal electric poling Received in revised form 18 February 2014 process performed under zero stress followed by (ii) a combined uniaxial compressive stress and heating Accepted 26 March 2014 process, (iii) an isothermal electric de-poling process under uniaxial stress, and finally (iv) the removal of compressive stress during a cooling process. The new cycle was demonstrated experimentally on [001]-poled PMN-28PT single crystals. The maximum power and energy densities obtained were Keywords: 41 W/L and 41 J/L/cycle respectively for cold and hot source temperatures of 22 and 130 °C, electric field Pyroelectric materials between 0.2 and 0.95 MV/m, and with uniaxial load of 35.56 MPa at frequency of 1 Hz. -
Determining the Efficiency of the Hot-Air Engine As a Refrigerator
LD Heat Physics Thermodynamic cycle Leaflets P2.6.2.3 Hot-air engine: quantitative experiments Determining the efficiency of the hot-air engine as a refrigerator Objects of the experiments Measuring the heat Q2 extracted from the cylinder head during one revolution. Measuring the heat Q1 transferred to the cooling water during one revolution. Determining the efficiency of the refrigerator. Principles During one revolution, the hot-air engine, operated as a re- The efficiency is determined experimentally by driving the frigerator, extracts the heat Q2 from the cylinder head and flywheel of the hot-air engine with an electric motor at an transfers the heat Q1 to the cooling water. As heat is transferred angular speed f and determining the electric calorific power from the colder to the warmer reservoir, that is, in the opposite that permanently keeps the cylinder head at room temperature direction of spontaneous heat transfer, a certain amount of in a compensation measurement. The electric work supplied mechanical work W has to be supplied during one revolution. per revolution is equal to the heat Q2 extracted from the The refrigerator thus is a heat engine operated in the reverse cylinder head, that is direction. If there are no losses, the following relation between U ⋅ I the quantities involved holds: Q = (III) 2 f Q1 = Q2 + W (I). U: heating voltage, I: heating current The efficiency of a refrigerator is defined as the ratio In addition, the increase in temperature ⌬ of the cooling water Q is measured and the power transferred to the cooling water = 2 (II) ⌬V W P = c ⋅ ⋅ ⋅ ⌬ (IV) ⌬t c = 4.185 J g–1 K–1: specific heat capacity of water, = 1 g cm–3: density of water ⌬V : volume flow rate of the cooling water Determining the efficiency of the refrigerator ⌬t is determined.