Small-Scale Solar Thermal Combined Cycle
Overall Cost
European Commission,H2020
Project Description
Project Summary
The technology consists of a solar-driven micro gas-turbine as top cycle and an Organic Rankine Cycle as bottom cycle. There is no water requirement for cooling. A thermal energy storage is integrated between both cycles. The project will build a 60 kW prototype plant with a 2 MWh thermal storage unit and will validate this innovative power cycle in a relevant environment.
CIEMAT is responsible of the WP on Storage design and simulation. This system is based on a single concrete storage tank with filler and foundations also in concrete.
Technical Approach and Resources Used
The research team is engaged in
  • Materials compatibility of filler and HTF
  • Design and simulation of storage system
  • Experimental design
  • Evaluation of experimental results
Project Results (including any commercial outcomes)
Key Staff
POLYPHEM is an innovative small-scale and fully integrated solar CSP plant in which the solar energy is integrated in the top cycle and converted at high efficiency by the cascade of two cycles. Moreover, the micro gas-turbine can be operated in off-design conditions with air temperature at the inlet of the turbine decreased to about 700°C or less. In this condition, the turbine efficiency is decreased but no fuel back-up is needed, the plant is operated in solar-only mode. Through the integration of the thermal energy storage between top and bottom cycles, the project will bridge two individual power blocks to make a solar combined cycle power plant with unique flexibility.
  • Dr. Mª Esther Rojas
  • Margarita Rodriguez
  • Dr. Rocío Bayón