Recording and Evaluating the Pv Diagram with CASSY
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Physics 170 - Thermodynamic Lecture 40
Physics 170 - Thermodynamic Lecture 40 ! The second law of thermodynamic 1 The Second Law of Thermodynamics and Entropy There are several diferent forms of the second law of thermodynamics: ! 1. In a thermal cycle, heat energy cannot be completely transformed into mechanical work. ! 2. It is impossible to construct an operational perpetual-motion machine. ! 3. It’s impossible for any process to have as its sole result the transfer of heat from a cooler to a hotter body ! 4. Heat flows naturally from a hot object to a cold object; heat will not flow spontaneously from a cold object to a hot object. ! ! Heat Engines and Thermal Pumps A heat engine converts heat energy into work. According to the second law of thermodynamics, however, it cannot convert *all* of the heat energy supplied to it into work. Basic heat engine: hot reservoir, cold reservoir, and a machine to convert heat energy into work. Heat Engines and Thermal Pumps 4 Heat Engines and Thermal Pumps This is a simplified diagram of a heat engine, along with its thermal cycle. Heat Engines and Thermal Pumps An important quantity characterizing a heat engine is the net work it does when going through an entire cycle. Heat Engines and Thermal Pumps Heat Engines and Thermal Pumps Thermal efciency of a heat engine: ! ! ! ! ! ! From the first law, it follows: Heat Engines and Thermal Pumps Yet another restatement of the second law of thermodynamics: No cyclic heat engine can convert its heat input completely to work. Heat Engines and Thermal Pumps A thermal pump is the opposite of a heat engine: it transfers heat energy from a cold reservoir to a hot one. -
Physics 100 Lecture 7
2 Physics 100 Lecture 7 Heat Engines and the 2nd Law of Thermodynamics February 12, 2018 3 Thermal Convection Warm fluid is less dense and rises while cool fluid sinks Resulting circulation efficiently transports thermal energy 4 COLD Convection HOT Turbulent motion of glycerol in a container heated from below and cooled from above. The bright lines show regions of rapid temperature variation. The fluid contains many "plumes," especially near the walls. The plumes can be identified as mushroom-shaped objects with heat flowing through the "stalk" and spreading in the "cap." The hot plumes tend to rise with their caps on top; falling, cold plumes are cap-down. All this plume activity is carried along in an overall counterclockwise "wind" caused by convection. Note the thermometer coming down from the top of the cell. Figure adapted from J. Zhang, S. Childress, A. Libchaber, Phys. Fluids 9, 1034 (1997). See detailed discussion in Kadanoff, L. P., Physics Today 54, 34 (August 2001). 5 The temperature of land changes more quickly than the nearby ocean. Thus convective “sea breezes” blow ____ during the day and ____ during the night. A. onshore … onshore B. onshore … offshore C. offshore … onshore D. offshore … offshore 6 The temperature of land changes more quickly than the nearby ocean. Thus convective “sea breezes” blow ____ during the day and ____ during the night. A. onshore … onshore B.onshore … offshore C.offshore … onshore D.offshore … offshore 7 Thermal radiation Any object whose temperature is above zero Kelvin emits energy in the form of electromagnetic radiation Objects both absorb and emit EM radiation continuously, and this phenomenon helps determine the object’s equilibrium temperature 8 The electromagnetic spectrum 9 Thermal radiation We’ll examine this concept some more in chapter 6 10 Why does the Earth cool more quickly on clear nights than it does on cloudy nights? A. -
Fuel Cells Versus Heat Engines: a Perspective of Thermodynamic and Production
Fuel Cells Versus Heat Engines: A Perspective of Thermodynamic and Production Efficiencies Introduction: Fuel Cells are being developed as a powering method which may be able to provide clean and efficient energy conversion from chemicals to work. An analysis of their real efficiencies and productivity vis. a vis. combustion engines is made in this report. The most common mode of transportation currently used is gasoline or diesel engine powered automobiles. These engines are broadly described as internal combustion engines, in that they develop mechanical work by the burning of fossil fuel derivatives and harnessing the resultant energy by allowing the hot combustion product gases to expand against a cylinder. This arrangement allows for the fuel heat release and the expansion work to be performed in the same location. This is in contrast to external combustion engines, in which the fuel heat release is performed separately from the gas expansion that allows for mechanical work generation (an example of such an engine is steam power, where fuel is used to heat a boiler, and the steam then drives a piston). The internal combustion engine has proven to be an affordable and effective means of generating mechanical work from a fuel. However, because the majority of these engines are powered by a hydrocarbon fossil fuel, there has been recent concern both about the continued availability of fossil fuels and the environmental effects caused by the combustion of these fuels. There has been much recent publicity regarding an alternate means of generating work; the hydrogen fuel cell. These fuel cells produce electric potential work through the electrochemical reaction of hydrogen and oxygen, with the reaction product being water. -
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. -
Section 15-6: Thermodynamic Cycles
Answer to Essential Question 15.5: The ideal gas law tells us that temperature is proportional to PV. for state 2 in both processes we are considering, so the temperature in state 2 is the same in both cases. , and all three factors on the right-hand side are the same for the two processes, so the change in internal energy is the same (+360 J, in fact). Because the gas does no work in the isochoric process, and a positive amount of work in the isobaric process, the First Law tells us that more heat is required for the isobaric process (+600 J versus +360 J). 15-6 Thermodynamic Cycles Many devices, such as car engines and refrigerators, involve taking a thermodynamic system through a series of processes before returning the system to its initial state. Such a cycle allows the system to do work (e.g., to move a car) or to have work done on it so the system can do something useful (e.g., removing heat from a fridge). Let’s investigate this idea. EXPLORATION 15.6 – Investigate a thermodynamic cycle One cycle of a monatomic ideal gas system is represented by the series of four processes in Figure 15.15. The process taking the system from state 4 to state 1 is an isothermal compression at a temperature of 400 K. Complete Table 15.1 to find Q, W, and for each process, and for the entire cycle. Process Special process? Q (J) W (J) (J) 1 ! 2 No +1360 2 ! 3 Isobaric 3 ! 4 Isochoric 0 4 ! 1 Isothermal 0 Entire Cycle No 0 Table 15.1: Table to be filled in to analyze the cycle. -
Thermodynamic Cycles of Direct and Pulsed-Propulsion Engines - V
THERMAL TO MECHANICAL ENERGY CONVERSION: ENGINES AND REQUIREMENTS – Vol. I - Thermodynamic Cycles of Direct and Pulsed-Propulsion Engines - V. B. Rutovsky THERMODYNAMIC CYCLES OF DIRECT AND PULSED- PROPULSION ENGINES V. B. Rutovsky Moscow State Aviation Institute, Russia. Keywords: Thermodynamics, air-breathing engine, turbojet. Contents 1. Cycles of Piston Engines of Internal Combustion. 2. Jet Engines Using Liquid Oxidants 3. Compressor-less Air-Breathing Jet Engines 3.1. Ramjet engine (with fuel combustion at p = const) 4. Pulsejet Engine. 5. Cycles of Gas-Turbine Propulsion Systems with Fuel Combustion at a Constant Volume Glossary Bibliography Summary This chapter considers engines with intermittent cycles and cycles of pulsejet engines. These include, piston engines of various designs, pulsejet engines, and gas-turbine propulsion systems with fuel combustion at a constant volume. This chapter presents thermodynamic cycles of thermal engines in which the propulsive mass is a mixture of air and either a gaseous fuel or vapor of a liquid fuel (on the initial portion of the cycle), and gaseous combustion products (over the rest of the cycle). 1. Cycles of Piston Engines of Internal Combustion. Piston engines of internal combustion are utilized in motor vehicles, aircraft, ships and boats, and locomotives. They are also used in stationary low-power electric generators. Given the variety of conditions that engines of internal combustion should meet, depending on their functions, engines of various types have been designed. From the standpointUNESCO of thermodynamics, however, – i.e. EOLSS in terms of operating cycles of these engines, all of them can be classified into three groups: (a) engines using cycles with heat addition at a constant volume (V = const); (b) engines using cycles with heat addition at a constantSAMPLE pressure (p = const); andCHAPTERS (c) engines using the so-called mixed cycles, in which heat is added at either a constant volume or a constant pressure. -
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. -
Thermodynamic Analysis of Solar Absorption Cooling System Open Access Jasim Abdulateef1,, Sameer Dawood Ali1, Mustafa Sabah Mahdi2
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 60, Issue 2 (2019) 233-246 Journal of Advanced Research in Fluid Mechanics and Thermal Sciences Journal homepage: www.akademiabaru.com/arfmts.html ISSN: 2289-7879 Thermodynamic Analysis of Solar Absorption Cooling System Open Access Jasim Abdulateef1,, Sameer Dawood Ali1, Mustafa Sabah Mahdi2 1 Mechanical Engineering Department, University of Diyala, 32001 Diyala, Iraq 2 Chemical Engineering Department, University of Diyala, 32001 Diyala, Iraq ARTICLE INFO ABSTRACT Article history: This study deals with thermodynamic analysis of solar assisted absorption refrigeration Received 16 April 2019 system. A computational routine based on entropy generation was written in MATLAB Received in revised form 14 May 2019 to investigate the irreversible losses of individual component and the total entropy Accepted 18 July 2018 generation (푆̇ ) of the system. The trend in coefficient of performance COP and 푆̇ Available online 28 August 2019 푡표푡 푡표푡 with the variation of generator, evaporator, condenser and absorber temperatures and heat exchanger effectivenesses have been presented. The results show that, both COP and Ṡ tot proportional with the generator and evaporator temperatures. The COP and irreversibility are inversely proportional to the condenser and absorber temperatures. Further, the solar collector is the largest fraction of total destruction losses of the system followed by the generator and absorber. The maximum destruction losses of solar collector reach up to 70% and within the range 6-14% in case of generator and absorber. Therefore, these components require more improvements as per the design aspects. Keywords: Refrigeration; absorption; solar collector; entropy generation; irreversible losses Copyright © 2019 PENERBIT AKADEMIA BARU - All rights reserved 1. -
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 ..................................................................................................................................... -
Power Plant Steam Cycle Theory - R.A
THERMAL POWER PLANTS – Vol. I - Power Plant Steam Cycle Theory - R.A. Chaplin POWER PLANT STEAM CYCLE THEORY R.A. Chaplin Department of Chemical Engineering, University of New Brunswick, Canada Keywords: Steam Turbines, Carnot Cycle, Rankine Cycle, Superheating, Reheating, Feedwater Heating. Contents 1. Cycle Efficiencies 1.1. Introduction 1.2. Carnot Cycle 1.3. Simple Rankine Cycles 1.4. Complex Rankine Cycles 2. Turbine Expansion Lines 2.1. T-s and h-s Diagrams 2.2. Turbine Efficiency 2.3. Turbine Configuration 2.4. Part Load Operation Glossary Bibliography Biographical Sketch Summary The Carnot cycle is an ideal thermodynamic cycle based on the laws of thermodynamics. It indicates the maximum efficiency of a heat engine when operating between given temperatures of heat acceptance and heat rejection. The Rankine cycle is also an ideal cycle operating between two temperature limits but it is based on the principle of receiving heat by evaporation and rejecting heat by condensation. The working fluid is water-steam. In steam driven thermal power plants this basic cycle is modified by incorporating superheating and reheating to improve the performance of the turbine. UNESCO – EOLSS The Rankine cycle with its modifications suggests the best efficiency that can be obtained from this two phaseSAMPLE thermodynamic cycle wh enCHAPTERS operating under given temperature limits but its efficiency is less than that of the Carnot cycle since some heat is added at a lower temperature. The efficiency of the Rankine cycle can be improved by regenerative feedwater heating where some steam is taken from the turbine during the expansion process and used to preheat the feedwater before it is evaporated in the boiler. -
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. -
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.