1. Demonstration of Small Scale Solar Gas Turbine
Demonstration of Small Scale Solar Gas Turbine
Björn Laumert, KTH

2. Introduction – Project Purpose
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.

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

4. Concentrating Solar Power (CSP) Working Principle
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

5. Introduction – Small CSP GT Unit
Introduction – Small CSP GT Unit
Small scale units (power range 5-80 kWel)
High concentration ratio
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)

6. Brayton Engine Technology
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

7. Receiver – Working Principle
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

8. Receiver Brayton Cycle – KTH Technology
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

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

10.
Integrated Compact Receiver GT Unit – KTH Technology (Torsten Strand Design)
P = 25 kW
Electric Efficiency = 29,6%
Pressure ratio =3
TIT = 950 C

11. Experimental Verification and Demonstration
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

12. Solar Simulation Laboratory
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

13. Validation of Solar Simulator
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

14.
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)