HEAT POWERED CYCLES 2018 Book of Abstracts
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Performance Analysis of Two-Stage Transcritical Refrigeration Cycle Operating with R744
Proceedings of COBEM 2011 21 st Brazilian Congress of Mechanical Engineering Copyright © 2011 by ABCM October 24-28, 2011, Natal, RN, Brazil PERFORMANCE ANALYSIS OF TWO-STAGE TRANSCRITICAL REFRIGERATION CYCLE OPERATING WITH R744 Igor Marcel Gomes Almeida, [email protected] Studies Group in Refrigeration and Air-Conditioning. Federal Institute of Education, Science and Technology of Rio Grande do Norte. Santa Cruz-RN. Cleiton Rubens Formiga Barbosa, [email protected] Francisco de Assis Oliveira Fontes, [email protected] Federal University of Rio Grande do Norte. Department of Mechanical Engineering. Abstract. The present study is a theoretical analysis of a two-stage transcritical cooling cycle using R744 (carbon dioxide) as a refrigerant. The effect of the intercooling process on performance in the two-stage transcritical system is subjected to varying pressures in a gas cooler. Performance comparison between the single stage and two-stage cycle is also subject to the same operating conditions. We assessed the effects on system performance of pressure in the gas cooler, isentropic compressor efficiency, amount of intercooling between the two compression stages and discharge temperature of the refrigerant from the gas cooler. Thermodynamic analysis was carried out with CoolPack software, considering an evaporation temperature of -10 oC and refrigeration capacity of 5 kW. Results show the coefficient of performance (COP) for the two-stage cycle is superior to the single stage cycle. Two-stage compression was found to reduce energy consumption. On the whole, two-stage compression and the intercooling process are significant in increasing COP for these systems. Keywords : Natural refrigerants, Carbon dioxide, Performance, Two-stage compression, Transcritical cycle. -
Performance Comparison of Different Rankine Cycle Technologies Applied to Low and Medium Temperature Industrial Surplus Heat Scenarios
Paper ID: 175 Page 1 Performance Comparison of Different Rankine Cycle Technologies Applied to Low and Medium Temperature Industrial Surplus Heat Scenarios Goran Durakovic1*, Monika Nikolaisen2 SINTEF Energy Research, Gas technology, Trondheim, Norway [email protected] [email protected] * Corresponding Author ABSTRACT Energy intensive industries generate vast amounts of low-grade surplus heat, and potential for direct re- use can be limited due to insufficient local demand. Conversion of heat into electric power thus becomes an attractive option. However, heat-to-power conversion is limited by poor efficiencies for heat sources at low and medium temperatures. To optimally utilize the available energy, the choice of technology could be important. In this work, single-stage subcritical, dual-stage subcritical and single-stage transcritical Rankine cycle technologies were compared. The investigated heat sources are an air equivalent off-gas at 150°C and 200°C and a liquid heat source at 150°C. These were all evaluated with the same available duty. The Rankine cycles were compared with equal total heat exchanger areas to enable fair comparisons of different cycles, instead of comparing cycles based on equal pinch point temperature differences as is frequently reported in literature. Six working fluids were investigated for both heat source temperatures, and cycle optimization was performed to determine the best Rankine cycle for each working fluid. This means that the optimizer could choose between single-stage and dual-stage cycle during one optimization, and determine which gave the highest net power output. The results were benchmarked against single-stage subcritical Rankine cycles. The results showed that the cycle yielding the highest net power varied depending on the allowable total heat exchanger area. -
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. -
Advanced Organic Vapor Cycles for Improving Thermal Conversion Efficiency in Renewable Energy Systems by Tony Ho a Dissertation
Advanced Organic Vapor Cycles for Improving Thermal Conversion Efficiency in Renewable Energy Systems By Tony Ho A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Engineering – Mechanical Engineering in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Ralph Greif, Co-Chair Professor Samuel S. Mao, Co-Chair Professor Van P. Carey Professor Per F. Peterson Spring 2012 Abstract Advanced Organic Vapor Cycles for Improving Thermal Conversion Efficiency in Renewable Energy Systems by Tony Ho Doctor of Philosophy in Mechanical Engineering University of California, Berkeley Professor Ralph Greif, Co-Chair Professor Samuel S. Mao, Co-Chair The Organic Flash Cycle (OFC) is proposed as a vapor power cycle that could potentially increase power generation and improve the utilization efficiency of renewable energy and waste heat recovery systems. A brief review of current advanced vapor power cycles including the Organic Rankine Cycle (ORC), the zeotropic Rankine cycle, the Kalina cycle, the transcritical cycle, and the trilateral flash cycle is presented. The premise and motivation for the OFC concept is that essentially by improving temperature matching to the energy reservoir stream during heat addition to the power cycle, less irreversibilities are generated and more power can be produced from a given finite thermal energy reservoir. In this study, modern equations of state explicit in Helmholtz energy such as the BACKONE equations, multi-parameter Span- Wagner equations, and the equations compiled in NIST REFPROP 8.0 were used to accurately determine thermodynamic property data for the working fluids considered. Though these equations of state tend to be significantly more complex than cubic equations both in form and computational schemes, modern Helmholtz equations provide much higher accuracy in the high pressure regions, liquid regions, and two-phase regions and also can be extended to accurately describe complex polar fluids. -
Analysis of a CO2 Transcritical Refrigeration Cycle with a Vortex Tube Expansion
sustainability Article Analysis of a CO2 Transcritical Refrigeration Cycle with a Vortex Tube Expansion Yefeng Liu *, Ying Sun and Danping Tang University of Shanghai for Science and Technology, Shanghai 200093, China; [email protected] (Y.S.); [email protected] (D.T.) * Correspondence: [email protected]; Tel.: +86-21-55272320; Fax: +86-21-55272376 Received: 25 January 2019; Accepted: 19 March 2019; Published: 4 April 2019 Abstract: A carbon dioxide (CO2) refrigeration system in a transcritical cycle requires modifications to improve the coefficient of performance (COP) for energy saving. This modification has become more important with the system’s more and more widely used applications in heat pump water heaters, automotive air conditioning, and space heating. In this paper, a single vortex tube is proposed to replace the expansion valve of a traditional CO2 transcritical refrigeration system to reduce irreversible loss and improve the COP. The principle of the proposed system is introduced and analyzed: Its mathematical model was developed to simulate and compare the system performance to the traditional system. The results showed that the proposed system could save energy, and the vortex tube inlet temperature and discharge pressure had significant impacts on COP improvement. When the vortex tube inlet temperature was 45 ◦C, and the discharge pressure was 9 MPa, the COP increased 33.7%. When the isentropic efficiency or cold mass fraction of the vortex tube increased, the COP increased about 10%. When the evaporation temperature or the cooling water inlet temperature of the desuperheater decreased, the COP also could increase about 10%. The optimal discharge pressure correlation of the proposed system was established, and its influences on COP improvement are discussed. -
Advanced Power Cycles with Mixtures As the Working Fluid
Advanced Power Cycles with Mixtures as the Working Fluid Maria Jonsson Doctoral Thesis Department of Chemical Engineering and Technology, Energy Processes Royal Institute of Technology Stockholm, Sweden, 2003 Advanced Power Cycles with Mixtures as the Working Fluid Maria Jonsson Doctoral Thesis Department of Chemical Engineering and Technology, Energy Processes Royal Institute of Technology Stockholm, Sweden, 2003 TRITA-KET R173 ISSN 1104-3466 ISRN KTH/KET/R--173--SE ISBN 91-7283-443-9 Contact information: Royal Institute of Technology Department of Chemical Engineering and Technology, Division of Energy Processes SE-100 44 Stockholm Sweden Copyright © Maria Jonsson, 2003 All rights reserved Printed in Sweden Universitetsservice US AB Stockholm, 2003 Advanced Power Cycles with Mixtures as the Working Fluid Maria Jonsson Department of Chemical Engineering and Technology, Energy Processes Royal Institute of Technology, Stockholm, Sweden Abstract The world demand for electrical power increases continuously, requiring efficient and low-cost methods for power generation. This thesis investigates two advanced power cycles with mixtures as the working fluid: the Kalina cycle, alternatively called the ammonia-water cycle, and the evaporative gas turbine cycle. These cycles have the potential of improved performance regarding electrical efficiency, specific power output, specific investment cost and cost of electricity compared with the conventional technology, since the mixture working fluids enable efficient energy recovery. This thesis shows that the ammonia-water cycle has a better thermodynamic performance than the steam Rankine cycle as a bottoming process for natural gas- fired gas and gas-diesel engines, since the majority of the ammonia-water cycle configurations investigated generated more power than steam cycles. -
Turbocharged Diesel Engine Power Production Enhancement: Proposing a Novel Thermal-Driven Supercharging System Based on Kalina Cycle
Vol 1, No 2, 2020, 223-234 DOI: 10.22044/rera.2020.9521.1028 Turbocharged Diesel Engine Power Production Enhancement: Proposing a Novel Thermal-Driven Supercharging System based on Kalina Cycle 1 1 1 F. Salek , A. Eskandary Nasrabad and M.M. Naserian * 1- Department of Mechanical Engineering, Faculty of Montazeri, Khorasan Razavi Branch, Technical and Vocational University (TVU), Mashhad, Iran. Receive Date 3 April 2020; Revised 26 April 2020; Accepted Date 25 May 2020 *Corresponding authors: [email protected] (M. M. Naserian) Abstract In this paper, a novel thermal-driven supercharging system is proposed for downsizing of a turbocharged diesel engine. Furthermore, the Kalina cycle is used as a waste heat recovery system to run the mounted supercharging system. The waste heat of air in engine exhaust and intake pipes is converted to the cooling and mechanical power by the Kalina cycle. The mechanical power produced by the Kalina cycle is transferred to an air compressor to charge extra air to the engine in order to generate more power. This feature can be used for downsizing the turbo-charged heavy duty diesel engine. In addition, the heat rejected from the engine intercooler is transferred to the Kalina cycle vapor generator component, and part of the engine exhaust waste heat is also used for superheating the Kalina working fluid before entering the engine. Then the first and second law analyses are performed to assess the operation of the engine in different conditions. Moreover, an economic model is provided for the Kalina cycle, which is added to the engine as a supplementary component. -
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. -
Thermodynamics of Power Generation
THERMAL MACHINES AND HEAT ENGINES Thermal machines ......................................................................................................................................... 1 The heat engine ......................................................................................................................................... 2 What it is ............................................................................................................................................... 2 What it is for ......................................................................................................................................... 2 Thermal aspects of heat engines ........................................................................................................... 3 Carnot cycle .............................................................................................................................................. 3 Gas power cycles ...................................................................................................................................... 4 Otto cycle .............................................................................................................................................. 5 Diesel cycle ........................................................................................................................................... 8 Brayton cycle ..................................................................................................................................... -
Upgrading Both Geothermal and Solar Energy
GRC Transactions, Vol. 40, 2016 Upgrading Both Geothermal and Solar Energy Kewen Li1,2, Changwei Liu2, Youguang Chen3, Guochen Liu2, Jinlong Chen2 1Stanford University, Stanford Geothermal Program, Stanford CA, USA 2China University of Geosciences, Beijing 3Tsinghua University, Beijing [email protected] Keywords Hybrid solar-geothermal systems, solar energy, geothermal resources, exergy, high efficiency ABSTRACT Geothermal energy has many advantages over solar and other renewables. These advantages include: 1) weather-proof; 2) base-load power; 3) high stability and reliability with a capacity factor over 90% in many cases; 4) less land usage and less ecological effect; 5) high thermal efficiency. The total installed capacity of geothermal electricity, however, is much smaller than those of solar energy. On the other hand, solar energy, including photovoltaic (PV) and concentrated solar power (CSP), has a lot of disadvantages and problems even it has a greater installed power and other benefits. Almost all of the five advantages geothermal has are the disadvantages of solar. Furthermore, solar PV has a high pollution issue during manufacturing. There have been many reports and papers on the combination of geothermal and solar energies in recent decades. This article is mainly a review of these literatures and publications. Worldwide, there are many areas where have both high heat flow flux and surface radiation, which makes it possible to integrate geothermal and solar energies. High temperature geothermal resource is the main target of the geothermal industry. The fact is that there are many geothermal resources with a low or moderate temperature of about 150oC. It is known that the efficiency of power generation from ther- mal energy is directly proportional to the resource temperature in general. -
Energy Efficiency State of the Art of Available Low-Gwprefrigerants And
ENERGY EFFICIENCY STATE OF THE ART OF AVAILABLE LOW-GWP REFRIGERANTS AND SYSTEMS Final Report September 2018 Study commissioned by the AFCE and carried out by EReIE, the Cemafroid, and the CITEPA Authors : Stéphanie Barrault (CITEPA) Olivier Calmels (Cemafroid) Denis Clodic (EReIE) Thomas Michineau (Cemafroid) ACKNOWLEDGEMENTS We sincerely thank the members of the Steering Committee for their contributions: Bénédicte BALLOT-MIGUET, EDF Emmanuelle BRIERE, UNICLIMA Tristan HUBE, Service Entreprises et Dynamiques Industrielles, ADEME Laurent GUEGAN, François HEYNDRICKX, Régis LEPORTIER, François PIGNARD, AFCE. We would also like to thank all the professionals contacted as part of the study Copyright 2018 Any representation or reproduction in whole or in part without the consent of the authors or their heirs or successors is illegal according to the Code of Intellectual Property (Art. L 122-4) and constitutes an infringement punishable under the Criminal Code. Only are allowed (art. 122-5) copies or reproductions strictly reserved for private use and not intended for collective use, as well as analyzes and short quotations justified by the critical pedagogical character, or information the work to which they are incorporated, subject, however, to compliance with the provisions of Articles L122-10 to L122-12 of the Code, relating to reprographic reproduction. 2 / 131 Content CONTENT Content 3 List of Figures _________________________________________________________________ 6 List of Tables _________________________________________________________________ -
Comparison of ORC Turbine and Stirling Engine to Produce Electricity from Gasified Poultry Waste
Sustainability 2014, 6, 5714-5729; doi:10.3390/su6095714 OPEN ACCESS sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Article Comparison of ORC Turbine and Stirling Engine to Produce Electricity from Gasified Poultry Waste Franco Cotana 1,†, Antonio Messineo 2,†, Alessandro Petrozzi 1,†,*, Valentina Coccia 1, Gianluca Cavalaglio 1 and Andrea Aquino 1 1 CRB, Centro di Ricerca sulle Biomasse, Via Duranti sn, 06125 Perugia, Italy; E-Mails: [email protected] (F.C.); [email protected] (V.C.); [email protected] (G.C.); [email protected] (A.A.) 2 Università degli Studi di Enna “Kore” Cittadella Universitaria, 94100 Enna, Italy; E-Mail: [email protected] † These authors contributed equally to this work. * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +39-075-585-3806; Fax: +39-075-515-3321. Received: 25 June 2014; in revised form: 5 August 2014 / Accepted: 12 August 2014 / Published: 28 August 2014 Abstract: The Biomass Research Centre, section of CIRIAF, has recently developed a biomass boiler (300 kW thermal powered), fed by the poultry manure collected in a nearby livestock. All the thermal requirements of the livestock will be covered by the heat produced by gas combustion in the gasifier boiler. Within the activities carried out by the research project ENERPOLL (Energy Valorization of Poultry Manure in a Thermal Power Plant), funded by the Italian Ministry of Agriculture and Forestry, this paper aims at studying an upgrade version of the existing thermal plant, investigating and analyzing the possible applications for electricity production recovering the exceeding thermal energy. A comparison of Organic Rankine Cycle turbines and Stirling engines, to produce electricity from gasified poultry waste, is proposed, evaluating technical and economic parameters, considering actual incentives on renewable produced electricity.