[home] [Personal Program] [Help]

---

Session: Session 6B: System Design - Cycle configurations
Session starts: Wednesday 11 September, 09:00
Presentation starts: 09:00
Room: Attica

---

Jian Li (Tsinghua University)
Yuanyuan Duan (Tsinghua University)
Zhen Yang (Tsinghua University)

Abstract:
Dual-pressure evaporation cycle is an emerging cycle type in the organic Rankine cycle (ORC) field, which remarkably increases the conversion efficiency, and the adaptability to various heat sources is better compared with the conventional single-pressure evaporation cycle. However, the published studies on the dual-pressure evaporation cycle are mainly limited to the thermodynamic performance. The studies on the thermo-economic performance are insufficient to date. This study analyzed the thermo-economic performance of dual-pressure evaporation ORC system using R245fa for heat sources of 100–200°C. The heat exchangers are shell-and-tube type and the working fluid flows in the tubes. The effects of heat source temperature, mass flow rate of heat source fluid, and pinch point temperature differences (PPTDs) on the system thermo-economic performance were quantitatively analyzed. The thermo-economic performance of single-pressure and dual-pressure evaporation cycles was compared. Results show that the specific investment cost (SIC) of dual-pressure evaporation ORC system decreases as the heat source temperature increases. Increasing the mass flow rate of heat source fluid will substantially reduce the SIC. Increasing the PPTDs is beneficial to reduce the SIC at a high heat source temperature. The purchased costs of heat absorbers and condenser are two largest terms in the system, and their ratios to the total purchased equipment cost are 30.9%–49.5% and 32.9%–43.7%, respectively. The SIC of dual-pressure evaporation cycle increases by 5.7%–14.2% compared to the single-pressure evaporation cycle, and that is mainly ascribed to the remarkable increase in the purchased cost of heat absorbers.