A novel process design methodology for power cycle: From ideal heat matching to actual structures

Abstract

The power cycle is one of the most essential thermal-to-power systems and involves various working fluids and heat sources. This work proposes a novel three-stage process design methodology for the power cycle, encompassing performance optimization, operating condition optimization, and structural design. The first and second stages optimize the performance and operating conditions without structural constraints, representing an ideal cycle design. The third stage performs the structural design based on the optimal operating conditions determined in the previous stages. This stage employs a white-box model with a well-defined thermodynamic process. In this work, the method is applied to the case studies of single-pressure cycles and complex dual-pressure cycles. The net power output of the carbon dioxide transcritical power cycle was further improved by 5.07 % using this method. The single- and dual-pressure ammonia power cycles further increase the net power output by 51.51 % and 61.01 %, respectively, under the same heat source. The proposed method can optimize the operating conditions for the power cycle and design the optimal cycle structure under various operating conditions, providing a novel approach for the research and development of control strategies for variable cycle structures. Additionally, this method is highly generalized, allowing for easy modification of heat sources and working fluids without additional codes. This methodology avoids empirical selection, repetitive cycle structure modeling, and performance limitations with fixed cycle structures. Consequently, this work provides a rapid solution for customizing power cycles.