[Objective] Against the backdrop of the “dual carbon” goal and the high proportion of renewable energy grid integration

the challenge of absorbing curtailed photovoltaic(PV) power has become increasingly prominent

alongside issues such as high investment costs and relatively low energy efficiency in traditional solar thermal systems. To achieve efficient utilization of curtailed PV power and improve the overall energy efficiency and economic viability of solar thermal systems

this paper proposes a novel PV-tower solar thermal hybrid system driven by a Carnot battery

and conducts research on system architecture design and collaborative optimization. [Methods] To address the technical bottleneck of limited outlet temperature in Carnot battery compressors

a staged temperature-rise scheme combining “compressor heat recovery and electric heater series connection” was designed. Using the EBSILON professional software

a thermodynamic coupling model of the system was constructed. A standalone CSP system and a CSP system coupled with an electric heater were set as reference schemes. By replacing part of the heliostat field with a Carnot battery

a comparative analysis was conducted in terms of energy efficiency

exergy efficiency

and economic viability. [Results] The study indicates that the overall energy efficiency of the new parallel system reaches 39.28%

representing improvements of 6.00% and 10.84% over the two reference systems

respectively. The overall exergy efficiency reaches 41.80%

representing improvements of 5.29% and 11.35%

respectively. Compared to a standalone CSP system

the new scheme reduces equipment and land costs by approximately 11 million yuan

increases lifetime electricity sales revenue by 811 million yuan

and shortens the dynamic payback period by 7.11 years. [Conclusion] This novel Carnot battery-solar thermal parallel system can efficiently absorb curtailed PV power

offering the dual advantages of improved energy efficiency and cost optimization. It provides a feasible technical pathway and theoretical support for the engineering application of complementary PV-solar thermal systems.