Demonstration of Small Scale Solar Gas Turbine 2018-05-24 Demonstration of Small Scale Solar Gas Turbine Björn Laumert, KTH

Introduction – Project Purpose 2018-05-24 Introduction – Project Purpose Demonstration of a small solar-hybrid gas turbine, operating both with solar energy and back-up fuel Modification of solar lab facility to allow for integration of gas turbine in solar test bed Measurement of the efficiency of gas-turbine operation (fuel-electric as well as total conversion efficiency) with different intensities of solar heat input Measurement of the flexibility of the solar gas-turbine (ramp-rate in %/min) Evaluation of different control strategies for solar hybrid gas-turbine operation.

Solar Irradiation and Potential Power Production (PV or CSP) 2018-05-24 Solar Irradiation and Potential Power Production (PV or CSP) Area covers world’s total primary energy supply TPES 2007 with conversion efficiency 8%

Concentrating Solar Power (CSP) Working Principle 2018-05-24 Concentrating Solar Power (CSP) Working Principle Mirror directed normal to solar irradiation Light is reflected (concentrated) to a focal spot Light in focal spot is captured in receiver Light is absorbet in medium and transformed into heat Heat is used to drive heat to power conversion process Conversion process is Stirling, Rankine or Brayton cycle

Introduction – Small CSP GT Unit 2018-05-24 Introduction – Small CSP GT Unit Small scale units (power range 5-80 kWel) High concentration ratio 1000-4500 High working temperatures High efficiency: 30% system efficiency light to electric power Scalable through multiplication Limited in unit size Relatively expensive so far (in terms of LCOE), but relatively low unit cost Commercially available with Stirling engine, but not with GT Use as small scale power generation units in rural areas Hybridization and thermal storage to be introduced TRL today: 4-5 (components laboratory and field tested, but not optimized towards this application)

Brayton Engine Technology 2018-05-24 Brayton Engine Technology Siemens SGT-750 TIT 1120 C Pressure Ratio 24 Capstone 30 30 kW 27% el efficiency TIT 824 C Pressure ratio 3.64

Receiver – Working Principle 2018-05-24 Receiver – Working Principle Light is captured and absorbed in appropriate absorption material Absorption is process where electromagnetic wave energy is transferred to electrons in absorption material Heat is exchanged between absorption material and the heat transfer fluid or directy to the working fluid of the engine

Receiver Brayton Cycle – KTH Technology 2018-05-24 Receiver Brayton Cycle – KTH Technology Low cost, closed cavity receiver with ceramic through-flow absorber Low cost, open cavity, metal tube receiver with enhanced convection heat transfer by impingement jets Secondary CPC (optional) Inlet Absorber (changeable) Inflow mixing box Outlet

Verification Studies CFD Heat Transfer 2018-05-24 Verification Studies CFD Heat Transfer Radiative heat flux as boundary conditions Flow path and velocities Pressure loss and heat-transfer rates Metal temperatures radiation

2018-05-24 Integrated Compact Receiver GT Unit – KTH Technology (Torsten Strand Design) P = 25 kW Electric Efficiency = 29,6% Pressure ratio =3 TIT = 950 C

Experimental Verification and Demonstration 2018-05-24 Experimental Verification and Demonstration Validation of calculation models Demonstration of receiver technology Verification of receiver function (efficiency, thermo-mechanical and life) Demonstration of CSP plant, coupling receiver to micro turbine Analysis of receiver/combustion chamber interaction Analysis of system behavior

Solar Simulation Laboratory 2018-05-24 Solar Simulation Laboratory Relevant power: 12*7kW Xenon search light lamps 20 kW on target, drive micro turbine Designed to represent parabolic dish flux in focal point with help of Fresnel lenses Commissioning April 2014 Multi-purpose: CSP, CPV, Materials, solar reactor

Validation of Solar Simulator 2018-05-24 Validation of Solar Simulator Checked spectral distribution and compare with sunlight Built optical model of lamp and Fresnel lens for Ray-tracing Validated model flux measurements one lamp Modeled whole arrangement compare to real disk

2018-05-24 Next Steps Commissioning of Laboratory with integrated ventilation system for receiver-turbine tests (May 2014) Receiver tests and validation (May-December 2014) Integration of Micro-turbine (January 2015) System tests and demonstration (January-June 2015)