1. Steam Turbine Optimization for Solar Thermal Power Plant Operation
PROCESS3
Steam Turbine Optimization for Solar Thermal Power Plant Operation
Andrew Martin, Project Leader
James Spelling, Research Student

2. Solar Electric Technologies are Hot!
Huge upswing in PV investments
Still €€€/kWh
Perhaps most suitable for distributed generation
Concentrating Solar Power (CSP) being explored and deployed extensively
Spain, USA, Australia major players
Feed-in tariffs, Renewable Portfolio Standards major sources for subsidies

3. Types of Concentrating Solar Power (CSP) Systems
US DOE
US DOE
Power Tower
Parabolic Dish
US DOE
Ausra
Parabolic Trough
Linear Fresnel

4. CSP Plant Layout

5. Operational Challenges – Transient Behavior
Start up
Shut down

6. M. Jöcker, SIT

7. Project Objectives
Examine state-of-art CSP technology with focus on steam turbine optimization
Suggest practical ways of improving the performance and useful lifetime of the cycle components, notably:
Maintaining turbine temperature during stand-by
Integrating the performance of the steam turbine with the thermal energy storage unit
Optimization of start-up procedures

8. Methodology Development of dynamic component model of steam turbine
Simple 1D (axial) heat transfer model
Detailed 2D (axisymmetric) heat transfer model coupled with a Stodola steam expansion model
Development of system models
Complete system simulation model for gas turbine-based CSP is available
Simulation and optimisation of the solar trough plant
ST operational strategies via thermal energy storage
Comparison of component and system simulation results with experimental data from existing CSP plants

9. Workpackages and schedule
WP1 Literature review  (Anneli Carlqvist)
WP2 ST heat transfer models
WP2.1 1-D 
WP2.2 2-D  (just recently)
WP3 Component integration to system model
WP3.1 Thermal energy storage
WP3.2 Trough collectors and preliminary system simulations
WP3.3 System simulations and optimization
WP4 Licentiate thesis
Ca 6 month delay in completing WP2-WP4

10. 1D Steam Turbine Model
A initial 1D (radial) finite-difference model has been developed
Three zones considered, namely rotor, stator and insulation
Model to be correlated against the results of the more detailed 2D steam turbine model

11. Detailed Steam Turbine Model
A 2D finite volume model, developed in MATLAB to increase flexibility and allow integration with system model
Stodola models used to calculate off-design behavior of the steam expansion

12. Stodola models
Links the pressure ratio to the mass flow and temperature of the steam, and allows prediction of the off-design behavior of the turbine

13. Results to date: Temp vs. time

14. Results to date: 2-D profiles

15. Results to date: Animation

16. Main Components in Trough Plant System Model
Plant Component
Techniques
Feedwater Pump*
Mass/Energy Balance Operating Characteristic
Storage Tank*
Mass/Energy Balances
Steam Generator*
Pinch Analysis Techniques ε-NTU Techniques
Condenser*
Fan Drive Power Consumption
Parabolic Trough Field
(under development)
Molten Salt Thermodynamics
complete
*Spelling et al., ’Thermo-Economic Optimisation of Solar Tower Thermal Power Plants,’ ECOS 2010 (under review)

17. Ongoing Work
Obtain field data from the solar trough plant to use in validating the steam turbine model (WP2)
Development of the solar trough field model, based on heat and mass balance equations and trough incidence angle models (WP3)
Schedule (2010):
April 2-D ST turbine model ready (WP2)
July Integrated system model ready (WP3)
December Licentiate Report (WP4); completion of project

18. End of presentation