Comprehensive analysis and optimization for a novel combined heating and power system based on self-condensing transcritical CO2 Rankine cycle driven by geothermal energy from thermodynamic, exergoeconomic and exergoenvironmental aspects.

In this paper, a novel combined heating and power (CHP) system is proposed to realize full-scale utilization of geothermal energy and efficient multi-generation, which not only performs preferable overall performance than previous homogeneous system, but also offers an effective energy cascade utilization approach for self-condensing transcritical CO 2 (TCO 2) Rankine cycle. Based on the established mathematical models, the performance comparison is conducted for proving the superiority of the novel CHP system. Then, an overall performance analysis is implemented to reveal the combined effects for six key parameters on system thermodynamic, exergoeconomic and exergoenvironmental performances. Furthermore, multi-objective optimization considering system overall performance is conducted. The results show that for the novel CHP system, the largest relative improvement rate of system exergy efficiency (η exg) and declining rate of total unit product exergy cost (c P , total ) versus the previous CHP system are 15.03 % and 18.89 %, respectively. The final optimization results of η exg , c P , total and total unit product exergy environmental impact (b P , total ) are determined as 51.10 %, 14.12 $/GJ and 9.00 mPts/GJ, respectively. This paper fulfills an elaborate performance analysis and optimization for the novel CHP system, which fills the research gap of efficient and promising CHP system based on self-condensing TCO 2 Rankine cycle. • A novel self-condensing transcritical CO 2 cycle based cogeneration system is proposed. • Full-scale utilization of geothermal energy is realized by the novel system. • Overall performance superiority of the novel system is proved by comparison study. • Combined effects of six key parameters on system overall performance are revealed. • Multi-objective optimization of system overall performance is performed. [ABSTRACT FROM AUTHOR]