Transcript Demonstration of Small Scale Solar Gas Turbine

Demonstration of Small Scale Solar Gas Turbine
Björn Laumert, KTH
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Introduction – Project Purpose
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Demonstration of a small solar-hybrid gas turbine,
operating both with solar energy and back-up fuel
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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.
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Solar Irradiation and Potential
Power Production (PV or CSP)
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Area covers world’s total primary
energy supply TPES 2007 with
conversion efficiency 8%
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Concentrating Solar Power
(CSP) Working Principle
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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
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Introduction – Small CSP GT Unit
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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)
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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
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Receiver – Working Principle
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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
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Receiver Brayton Cycle – KTH
Technology
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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)
Absorber
(changeable)
Inlet
Inflow mixing
box
Outlet
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Verification Studies
CFD Heat Transfer
radiation
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Radiative heat flux as
boundary conditions
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Flow path and velocities
Pressure loss and heattransfer rates
Metal temperatures
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Integrated Compact Receiver GT Unit –
KTH Technology (Torsten Strand
Design)
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P = 25 kW
Electric Efficiency = 29,6%
Pressure ratio =3
TIT = 950 C
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Experimental Verification and
Demonstration
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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
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Solar Simulation Laboratory
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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
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Validation of Solar Simulator
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Checked spectral distribution and compare with sunlight
Built optical model of lamp and Fresnel lens for Raytracing
Validated model flux measurements one lamp
Modeled whole arrangement compare to real disk
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Next Steps
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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)
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