Modeling and Analysis of a Hybrid Solar-Dish Brayton Engine
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Modeling and Analysis of a Hybrid Solar-Dish Brayton Engine Sara Ghaem Sigarchian MasterSara Ghaemof Science Sigarchian Thesis KTH School of Industrial Engineering and Management EnergySemi Technology Final Report EGI - 2012Draft-Fe b Division of HPT SE-100 44 STOCKHOLM Master of Science Thesis EGI 2012:HPT Modeling and Analysis of a Hybrid Solar-Dish Brayton Engine Sara Ghaem Sigarchian Approved Examiner Supervisors Date Prof. Torsten Fransson Anders Malmquist , Torsten Strand Commissioner Contact person ABSTRACT The negative environmental impacts of fossil-fuel electricity production emphasize on using more renewable energy sources in power generation. Electricity production using solar energy is well known as one of the promising solutions for ever-growing problems of global warming and limited supply of fossil fuels. It is well known that dish-engine systems demonstrate the highest solar-to-electric efficiencies, compared to other solar technologies [1, 2]. High efficiency, hybridization potential, modularity and low cost potential make them excellent candidates for small-scale decentralized power generation [1, 2]. A number of units can be grouped together to form a dish-engine farm and produces the desired electrical output [1] In most contemporary dish-engine systems, Stirling engines [3] have been used as the power conversion unit; however, small-scale externally-fired, recuperated gas turbines (EFGT) would appear to have considerable potential to be used in solar-fossil fuel hybrid dish systems. An EFGT integrated with a solar receiver is known as a dish-Brayton. They show a number of advantages when compared with Stirling engine systems, chief amongst them a significant reduction in O&M costs and simplified hybridization schemes. Recent developments in the fields of high-temperature recuperators will allow EFGT systems to compete directly with Stirling engines in terms of efficiency. The hybrid solar gas turbine can be configured in several different fashions, with the key difference being the relative positions of the solar receiver and combustor as well as the operation mode of the combustor. The aim of this thesis is to study, model and analysis the hybrid solar dish-Brayton cycle. Models are based on a 5 kW Micro gas turbine that belongs to Compower company [4] which is available at KTH energy department. A thermodynamic model implemented in Engineering Equation Solver (EES) is developed for various configurations. The performance of different possible integrated layouts are studied and compared. II ACKNOWLEDGEMENTS I am heartily thankful to my supervisors, Prof. Torsten Strand and Dr. Anders Malmquist for their encouragement, guidance from the initial to the final level enabling me to develop an understanding of the subject, for their kind support, valuable lessons and never getting tired of my endless questions. I would also like to thank our division head Prof. Torsten Fransson, for giving me the opportunity to study in this department and all supports during my study period. Many thanks to my dear colleagues in solar lab group at the Department of Energy Technology especially Dr. Bjorn Laumert, James Spelling and Wujun Wang with all great ideas and sharing their valuable experiences with me. I gratefully acknowledge Compower AB and especially Dr. Anders Malmquist the CEO of the company for giving me the opportunity to work on the micro gas turbine , providing all the needed information during the project , sharing great experiences and knowledge and supporting me in different stages of the project. I would like to give my special thanks to InnoEnergy Company for supporting this project, their promising program, future plans and support for continuing this work through the Polygeneration project. I would also like to say thank you to all my colleagues and friends especially Mariam Nafisi for their great support and recommendations during my work. Last but not the least, I offer my regards and blessings to my family, for their lifelong support. III TABLE OF CONTENTS ABSTRACT ....................................................................................................................................................... II ACKNOWLEDGEMENTS ............................................................................................................................. III TABLE OF CONTENTS ................................................................................................................................ IV LIST OF FIGURES ......................................................................................................................................... VI LIST OF TABLES ......................................................................................................................................... VIII NOMENCLATURE ........................................................................................................................................ IX 1 BACKGROUND .................................................................................................................................... 11 2 OBJECTIVES ......................................................................................................................................... 12 3 SCOPE OF THE PROJECT ................................................................................................................... 12 4 SYSTEM DESCRIPTION ...................................................................................................................... 13 4.1 COMPOWER MICRO GAS TURBINE[4] .................................................................................................. 13 4.1.1 Turbogenerator .............................................................................................................................. 13 4.1.2 Turbine and compressor .................................................................................................................. 13 4.1.3 Electrical generator ......................................................................................................................... 14 4.1.4 Combustion chamber ...................................................................................................................... 14 4.1.5 Recuperator .................................................................................................................................. 14 4.1.6 System Specification ....................................................................................................................... 15 4.2 TEST RESULT OVERVIEW .................................................................................................................... 17 4.3 SOLAR HYBRID SYSTEM ....................................................................................................................... 20 4.3.1 Parabolic Dish Concentrator ............................................................................................................ 20 4.3.2 Solar Receiver ............................................................................................................................... 22 5 SYSTEM LAYOUTS .............................................................................................................................. 23 6 SYSTEM MODEL .................................................................................................................................. 27 6.1 GENERAL OVERVIEW ......................................................................................................................... 27 6.2 MODEL THEORY ................................................................................................................................. 28 7 MODEL RESULTS AND ANALYSIS ................................................................................................... 31 7.1 LAYOUT 1 - MGT STANDALONE SYSTEM ............................................................................................. 31 7.1.1 Test and model comparison .............................................................................................................. 31 7.2 LAYOUT 2, PURE-SOLAR GAS TURBINE WITH THE ATMOSPHERIC RECEIVER ......................................... 35 7.3 LAYOUT 3, PURE-SOLAR GAS TURBINE WITH THE PRESSURIZED RECEIVER ........................................... 36 7.4 LAYOUT 2 AND 3 COMPARISON ........................................................................................................... 38 IV 7.5 LAYOUT 4A, FULL HYBRID CONFIGURATION WITH THE ATMOSPHERIC RECEIVER ................................ 42 7.6 LAYOUT 4B, FULL HYBRID CONFIGURATION WITH THE ATMOSPHERIC RECEIVER ............................... 43 7.7 LAYOUT 4C- FULL HYBRID CONFIGURATION WITH THE ATMOSPHERIC RECEIVER ............................... 45 7.8 LAYOUT 4A,4B,4C COMPARISON ......................................................................................................... 46 7.9 LAYOUT 5A- FULL HYBRID CONFIGURATION WITH PRESSURIZED RECEIVER ....................................... 48 7.10 LAYOUT 5B- FULL HYBRID CONFIGURATION WITH THE PRESSURIZED RECEIVER ................................ 50 7.11 LAYOUT 5C- FULL HYBRID CONFIGURATION WITH THE PRESSURIZED RECEIVER ................................ 51 7.12 LAYOUT 5A,5B,5C COMPARISON ......................................................................................................... 53 7.13 LAYOUT 4 AND 5 COMPARISON...........................................................................................................