Construction of multi-loop thermodynamic cycles: Methodology and case study

Developing renewable energy and improving the efficiency of the existing energy system are effective measures to realize CO2 emission reduction. This makes the energy utilization scenario more and more complex, which leads to the energy system needing to be able to utilize multiple heat source fluids and output multiple products. Compared with single-loop thermodynamic cycles (such as the basic configurations of Organic Rankine Cycle and Brayton Cycle), multi-loop thermodynamic cycles are more suitable for such complex energy utilization scenarios because of their complexity and variability. However, there is no systematic construction method for multi-loop thermodynamic cycles in the existing studies. Therefore, a novel construction method for multi-loop thermodynamic cycles is proposed based on the mapping from closed curves to thermodynamic cycles in this study. The multi-loop thermodynamic cycle is constructed by replacing edges of the closed curve with different thermodynamic processes. The effectiveness of the proposed method is demonstrated using a test case of the double-pressure Brayton cycle and a summary of ten existing multi-loop thermodynamic cycles. The proposed method provides a new perspective for the construction of multi-loop thermodynamic cycles. This makes research on the construction of thermodynamic cycles more theoretical, which is beneficial to obtain some novel multi-loop thermodynamic cycles.