A thermodynamically equivalent transformation method for the design and performance analysis of absorption cycles

• Thermodynamically equivalent transformation method for absorption cycle is proposed. • The method makes the decomposition of complex cycles into basic cycles convenient. • A method for COP calculation based on cycle decomposition is proposed and verified. • Applicability and potential of these methods is demonstrated by two case studies. Absorption cycles are a very promising technology for the provision of heating or cooling. Systems based on such cycles are capable of utilizing environmentally-friendly thermal energy sources such as low-grade solar or waste heat. Increasingly advanced absorption cycles with complex configurations are being proposed to meet the diversified demands of modern energy systems, however, a convenient, rapid yet accurate method for the design and performance analysis of these complex cycles is lacking. In this paper, a thermodynamically equivalent transformation method is proposed which decomposes complex cycles into mutually coupled basic single-stage cycles. Based on the decomposition transformation, a generalized method for the fast calculation of the COP of complex cycles under both ideal and practical conditions was also established and verified. Two case studies on the configuration design, performance analysis and optimization of complex absorption cooling cycles are performed to demonstrate the applicability of the proposed method. The results show that the proposed thermodynamically equivalent transformation method can make the decomposition of complex cycles convenient and effective. Although the present paper focuses on absorption cooling cycles, the method is equally applicable to absorption heat pump cycles. The established fast COP prediction method is computationally efficient and accurate for the performance analysis of absorption cycles with complex configurations. This study provides a powerful tool for the design, performance analysis and optimization of next-generation advanced absorption cycles.