Moving thermal energy from receiver to conversion system
Heat transfer from the concentrator receiver to the power block depends on the chosen heat transfer fluid (HTF) and system design. Common HTFs include molten salts, thermal oils, pressurized water/steam, and gases like air or nitrogen.
Typical transfer routes:
- Direct HTF loop: receiver heats the HTF which is pumped to a heat exchanger in the power block where it generates steam for turbines.
- Indirect transfer: receiver heats an intermediate fluid that then exchanges heat with a working fluid in the power block, isolating the turbine from corrosive or high-temperature fluids.
- Thermal storage coupling: HTF can be routed to storage tanks and later returned to supply the power block when needed.
Design considerations:
- Thermochemical stability: HTF must remain stable at operating temperatures.
- Pumping and piping losses: fluid viscosity and temperature affect pumping energy and insulation requirements.
- Heat exchanger efficiency: good heat transfer minimizes temperature drops and increases system efficiency.
A well-designed heat transfer chain is crucial to convert concentrated solar heat into reliable electricity with minimal losses.