Energy Conversion with Heat Engines
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Geothermal Power Plants and Novel Exhaust Heat Recovery Systems
Maximizing power output of heat engines through design optimization: Geothermal power plants and novel exhaust heat recovery systems Thèse Noémie Chagnon-Lessard Doctorat en génie mécanique Philosophiæ doctor (Ph. D.) Québec, Canada © Noémie Chagnon-Lessard, 2020 Maximizing power output of heat engines through design optimization: Geothermal power plants and novel exhaust heat recovery systems Thèse Noémie Chagnon-Lessard Sous la direction de : François Mathieu-Potvin, directeur de recherche Louis Gosselin, codirecteur de recherche Résumé Le design de machines thermiques menant à une puissance maximale dépend souvent des températures de la source chaude et de la source froide. C’est pourquoi dégager des lignes directrices à partir des designs optimaux de ces machines selon diverses températures d’opération peut faciliter leur conception. Une telle étude est proposée par cette thèse pour deux types de systèmes thermiques. En premier lieu, le cycle de Rankine organique (ORC) est un cycle thermodynamique de puissance utilisé entre autres dans les centrales géothermiques exploitant des réservoirs à basse température. Depuis quelques années, ce type de centrales suscite un vif intérêt à travers le monde, étant un des modes de production de puissance parmi les plus respectueux de l’environnement. Il s’agit de pomper un géofluide du sol pour transférer sa chaleur à un fluide de travail qui opère en cycle fermé, et de le réinjecter ensuite dans le bassin géologique. Les chercheurs tentent actuellement de mieux caractériser le potentiel géothermique de divers environnements géologiques. Le sous-sol du Québec est relativement froid, alors des études essaient de déterminer s’il serait possible d’y exploiter de manière rentable des centrales géothermiques. -
Thermodynamic Optimization of an Organic Rankine Cycle for Power Generation from a Low Temperature Geothermal Heat Source
Thermodynamic Optimization of an Organic Rankine Cycle for Power Generation from a Low Temperature Geothermal Heat Source Inés Encabo Cáceres Roberto Agromayor Lars O. Nord Department of Energy and Process Engineering Norwegian University of Science and Technology (NTNU) Kolbjørn Hejes v.1B, NO-7491 Trondheim, Norway [email protected] Abstract fueled by natural gas or other fossil fuels (Macchi and Astolfi, 2017). However, during the last years, the The increasing concern on environment problems has increasing concern of the greenhouse effect and climate led to the development of renewable energy sources, change has led to an increase of renewable energy, such being the geothermal energy one of the most promising as wind and solar power. In addition to these listed ones in terms of power generation. Due to the low heat renewable energies, there is an energy source that shows source temperatures this energy provides, the use of a promising future due to the advantages it provides Organic Rankine Cycles is necessary to guarantee a when compared to other renewable energies. This good performance of the system. In this paper, the developing energy is geothermal energy, and its optimization of an Organic Rankine Cycle has been advantages are related to its availability (Macchi and carried out to determine the most suitable working fluid. Astolfi, 2017): it does not depend on the ambient Different cycle layouts and configurations for 39 conditions, it is stable, and it offers the possibility of different working fluids were simulated by means of a renewable energy base load operation. One of the Gradient Based Optimization Algorithm implemented challenges of geothermal energy is that it does not in MATLAB and linked to REFPROP property library. -
Transcritical Pressure Organic Rankine Cycle (ORC) Analysis Based on the Integrated-Average Temperature Difference in Evaporators
Applied Thermal Engineering 88 (2015) 2e13 Contents lists available at ScienceDirect Applied Thermal Engineering journal homepage: www.elsevier.com/locate/apthermeng Research paper Transcritical pressure Organic Rankine Cycle (ORC) analysis based on the integrated-average temperature difference in evaporators * Chao Yu, Jinliang Xu , Yasong Sun The Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilizations, North China Electric Power University, Beijing 102206, PR China article info abstract Article history: Integrated-average temperature difference (DTave) was proposed to connect with exergy destruction (Ieva) Received 24 June 2014 in heat exchangers. Theoretical expressions were developed for DTave and Ieva. Based on transcritical Received in revised form pressure ORCs, evaporators were theoretically studied regarding DTave. An exact linear relationship be- 12 October 2014 tween DT and I was identified. The increased specific heats versus temperatures for organic fluid Accepted 11 November 2014 ave eva protruded its TeQ curve to decrease DT . Meanwhile, the decreased specific heats concaved its TeQ Available online 20 November 2014 ave curve to raise DTave. Organic fluid in the evaporator undergoes a protruded TeQ curve and a concaved T eQ curve, interfaced at the pseudo-critical temperature point. Elongating the specific heat increment Keywords: fi Organic Rankine Cycle section and shortening the speci c heat decrease section improved the cycle performance. Thus, the fi Integrated-average temperature difference system thermal and exergy ef ciencies were increased by increasing critical temperatures for 25 organic Exergy destruction fluids. Wet fluids had larger thermal and exergy efficiencies than dry fluids, due to the fact that wet fluids Thermal match shortened the superheated vapor flow section in condensers. -
An Analysis of the Brayton Cycle As a Cryogenic Refrigerator
jbrary, E-01 Admin. BJdg. OCT 7 1968 NBS 366 An Analysis of the Brayton Cycle As a Cryogenic Refrigerator ITATIONAL BURSAL' OF iTANDABD8 LIBRABT MAR 6 J973 V* 0F c J* 0a <5 Q \ v S. DEPARTMENT OF COMMERCE in Q National Bureau of Standards %. *^CAU 0? * : NATIONAL BUREAU OF STANDARDS The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. Today, in addition to serving as the Nation's central measurement laboratory, the Bureau is a principal focal point in the Federal Government for assuring maxi- mum application of the physical and engineering sciences to the advancement of tech- nology in industry and commerce. To this end the Bureau conducts research and provides central national services in three broad program areas and provides cen- tral national services in a fourth. These are: (1) basic measurements and standards, (2) materials measurements and standards, (3) technological measurements and standards, and (4) transfer of technology. The Bureau comprises the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, and the Center for Radiation Research. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consistent system of physical measurement, coor- dinates that system with the measurement systems of other nations, and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of an Office of Standard Reference Data and a group of divisions organized by the following areas of science and engineering Applied Mathematics—Electricity—Metrology—Mechanics—Heat—Atomic Phys- 2 2 ics—Cryogenics-—Radio Physics-—Radio Engineering —Astrophysics —Time and Frequency. -
A Turbo-Brayton Cryocooler for Future European Observation Satellite Generation
C19_078 1 A Turbo-Brayton Cryocooler for Future European Observation Satellite Generation J. Tanchon1, J. Lacapere1, A. Molyneaux2, M. Harris2, S. Hill2, S.M. Abu-Sharkh2, T. Tirolien3 1Absolut System SAS, Seyssinet-Pariset, France 2Ofttech, Gloucester, United Kingdom 3European Space Agency, Noordwijk, The Netherlands ABSTRACT Several types of active cryocoolers have been developed for space and military applications in the last ten years. Performances and reliability continuously increase to follow the requirements evolution of new generations of satellite: less power consumption, more cooling capacity, increased life duration. However, in addition to this increase of performances and reliability, the microvibrations re- quirement becomes critical. In fact, with the development of vibration-free technologies, classical Earth Observation cryocoolers (Stirling, Pulse Tube) will become the main source of microvibra- tions on-board the satellite. A new generation cryocooler is being developed at Absolut System using very high speed turbomachines in order to avoid any generated perturbations below 1000 Hz. This development is performed in the frame of ESA Technical Research Program - 4000113495/15/NL/KML. This paper presents the status of this development project based on Reverse Brayton cycle with very high speed turbomachines. INTRODUCTION The space cryogenics sector is characterized by a large number of applications (detection, im- aging, sample conservation, propulsion, telecommunications etc.) that lead to various requirements (temperature range, microvibration, lifetime, power consumption etc.) that can be met by different solutions (Stirling or JT coolers, mechanical or sorption compressors etc.). The recent years saw, in Europe, the developments of coolers to meet Earth Observation mission UHTXLUHPHQWVWKDWDUHFDSDEOHWRSURYLGHVLJQL¿FDQWFRROLQJSRZHUDWDQRSHUDWLRQDOWHPSHUDWXUH around 50K (for IR detection). -
First and Second Law Evaluation of Combined Brayton-Organic Rankine Power Cycle
Journal of Thermal Engineering, Vol. 6, No. 4, pp. 577-591, July, 2020 Yildiz Technical University Press, Istanbul, Turkey FIRST AND SECOND LAW EVALUATION OF COMBINED BRAYTON-ORGANIC RANKINE POWER CYCLE Önder Kaşka1, Onur Bor2, Nehir Tokgöz3* Muhammed Murat Aksoy4 ABSTRACT In the present work, we have conducted thermodynamic analysis of an organic Rankine cycle (ORC) using waste heat from intercooler and regenerator in Brayton cycle with intercooling, reheating, and regeneration (BCIRR). First of all, the first law analysis is used in this combined cycle. Several outputs are revealed in this study such as the cycle efficiencies in Brayton cycle which is dependent on turbine inlet temperature, intercooler pressure ratios, and pinch point temperature difference. For all cycles, produced net power is increased because of increasing turbine inlet temperature. Since heat input to the cycles takes place at high temperatures, the produced net power is increased because of increasing turbine inlet temperature for all cycles. The thermal efficiency of combined cycle is higher about 11.7% than thermal efficiency of Brayton cycle alone. Moreover, the net power produced by ORC has contributed nearly 28650 kW. The percentage losses of exergy for pump, turbine, condenser, preheater I, preheater II, and evaporator are 0.33%, 33%, 22%, 23%, 6%, and16% respectively. The differences of pinch point temperature on ORC net power and efficiencies of ORC are investigated. In addition, exergy efficiencies of components with respect to intercooling pressure ratio and evaporator effectiveness is presented. Exergy destructions are calculated for all the components in ORC. Keywords: Brayton Cycle, Organic Rankine Cycle, Bottoming Cycle, Pinch Point Temperature, Waste Heat, Energy and Exergy Analysis INTRODUCTION Thermal energy systems as well as corresponding all parts have been challenged to improve overall efficiency due to lack of conventional fuels, reduce climate change and so on for recent years. -
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. -
Sustainable Energy Conversion Through the Use of Organic Rankine Cycles for Waste Heat Recovery and Solar Applications
ENERGY SYSTEMS RESEARCH UNIT AEROSPACE AND MECHANICAL ENGINEERING DEPARTMENT UNIVERSITY OF LIÈGE Sustainable Energy Conversion Through the Use of Organic Rankine Cycles for Waste Heat Recovery and Solar Applications. in Partial Fulfillment of the Requirements for the Degree of Doctor of Applied Sciences Presented to the Faculty of Applied Science of the University of Liège (Belgium) by Sylvain Quoilin Liège, October 2011 Introductory remarks Version 1.1, published in October 2011 © 2011 Sylvain Quoilin 〈►[email protected]〉 Licence. This work is licensed under the Creative Commons Attribution - No Derivative Works 2.5 License. To view a copy of this license, visit ►http://creativecommons.org/licenses/by-nd/2.5/ or send a letter to Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 94105, USA. Contact the author to request other uses if necessary. Trademarks and service marks. All trademarks, service marks, logos and company names mentioned in this work are property of their respective owner. They are protected under trademark law and unfair competition law. The importance of the glossary. It is strongly recommended to read the glossary in full before starting with the first chapter. Hints for screen use. This work is optimized for both screen and paper use. It is recommended to use the digital version where applicable. It is a file in Portable Document Format (PDF) with hyperlinks for convenient navigation. All hyperlinks are marked with link flags (►). Hyperlinks in diagrams might be marked with colored borders instead. Navigation aid for bibliographic references. Bibliographic references to works which are publicly available as PDF files mention the logical page number and an offset (if non-zero) to calculate the physical page number. -
Design of a Cryogenic Turbine for a Hybrid Cryocooler
Design of a Cryogenic Turbine for a Hybrid Cryocooler by Thomas L. Fraser A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (Mechanical Engineering) at the UNIVERISTY OF WISCONSIN-MADISON 2006 Approved by _____________________________________________ ______________ Professor Gregory F. Nellis Date i Abstract The hybrid pulse tube-reverse Brayton cycle cryocooler has the potential for cooling to temperatures on the order of 10 K. By using the rectifying interface which converts the oscillating pulse tube flow to continuous flow, both vibrations and low temperature regenerator losses are overcome, making the hybrid an ideal candidate for cooling infrared focal plane arrays which demand low temperature and low vibration. However, the turboexpander within the reverse Brayton cycle is complex and its performance is highly dependent on the performance of its subcomponents, thus necessitating a model predicting the turboexpander performance. A model was developed to predict the performance of the reverse Brayton cycle stage including the recuperative heat exchanger and turboexpander components. The turboexpander was numerically modeled in detail to include the sub-models of rotordynamics, the thermal and leakage performance of the seal, and the turboalternator. Where possible, the models were verified against either an analytical model or experimental data. A parametric analysis was carried out to determine the optimal design and conditions for the turboexpander. ii Acknowledgements First and foremost I would like to thank Greg Nellis. Besides being my advisor for this project he is also responsible for sparking an interest in energy science through his heat transfer courses I took as an undergrad. -
Rankine Cycle Definitions
Rankine Cycle Reading Problems 11.1 ! 11.7 11.29, 11.36, 11.43, 11.47, 11.52, 11.55, 11.58, 11.74 Definitions • working fluid is alternately vaporized and condensed as it recirculates in a closed cycle • the standard vapour cycle that excludes internal irreversibilities is called the Ideal Rankine Cycle Analyze the Process Device 1st Law Balance Boiler h2 + qH = h3 ) qH = h3 − h2 (in) Turbine h3 = h4 + wT ) wT = h3 − h4 (out) Condenser h4 = h1 + qL ) qL = h4 − h1 (out) Pump h1 + wP = h2 ) wP = h2 − h1 (in) 1 The Rankine efficiency is net work output ηR = heat supplied to the boiler (h − h ) + (h − h ) = 3 4 1 2 (h3 − h2) Effects of Boiler and Condenser Pressure We know the efficiency is proportional to T η / 1 − L TH The question is ! how do we increase efficiency ) TL # and/or TH ". 1. INCREASED BOILER PRESSURE: • an increase in boiler pressure results in a higher TH for the same TL, therefore η ". • but 40 has a lower quality than 4 – wetter steam at the turbine exhaust – results in cavitation of the turbine blades – η # plus " maintenance • quality should be > 80 − 90% at the turbine exhaust 2 2. LOWER TL: • we are generally limited by the T ER (lake, river, etc.) eg. lake @ 15 ◦C + ∆T = 10 ◦C = 25 ◦C | {z } resistance to HT ) Psat = 3:169 kP a. • this is why we have a condenser – the pressure at the exit of the turbine can be less than atmospheric pressure 3. INCREASED TH BY ADDING SUPERHEAT: • the average temperature at which heat is supplied in the boiler can be increased by superheating the steam – dry saturated steam from the boiler is passed through a second bank of smaller bore tubes within the boiler until the steam reaches the required temperature – The value of T H , the mean temperature at which heat is added, increases, while TL remains constant. -
Supercritical Carbon Dioxide(S-CO2) Power Cycle for Waste Heat Recovery: a Review from Thermodynamic Perspective
processes Review Supercritical Carbon Dioxide(s-CO2) Power Cycle for Waste Heat Recovery: A Review from Thermodynamic Perspective Liuchen Liu, Qiguo Yang and Guomin Cui * School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; [email protected] (L.L.); [email protected] (Q.Y.) * Correspondence: [email protected] Received: 11 October 2020; Accepted: 13 November 2020; Published: 15 November 2020 Abstract: Supercritical CO2 power cycles have been deeply investigated in recent years. However, their potential in waste heat recovery is still largely unexplored. This paper presents a critical review of engineering background, technical challenges, and current advances of the s-CO2 cycle for waste heat recovery. Firstly, common barriers for the further promotion of waste heat recovery technology are discussed. Afterwards, the technical advantages of the s-CO2 cycle in solving the abovementioned problems are outlined by comparing several state-of-the-art thermodynamic cycles. On this basis, current research results in this field are reviewed for three main applications, namely the fuel cell, internal combustion engine, and gas turbine. For low temperature applications, the transcritical CO2 cycles can compete with other existing technologies, while supercritical CO2 cycles are more attractive for medium- and high temperature sources to replace steam Rankine cycles. Moreover, simple and regenerative configurations are more suitable for transcritical cycles, whereas various complex configurations have advantages for medium- and high temperature heat sources to form cogeneration system. Finally, from the viewpoints of in-depth research and engineering applications, several future development directions are put forward. This review hopes to promote the development of s-CO2 cycles for waste heat recovery.