Thermodynamic analysis and parametric optimization of CDTPC-ARC based on cascade use of waste heat of heavy-duty internal combustion engines (ICEs)

This paper proposes a novel carbon dioxide transcritical power cycle combined with an absorption refrigeration cycle (CDTPC-ARC) to recover waste heat from jacket water and exhaust gas of heavy-duty ICEs. Firstly, a detailed study is conducted to investigate the effects of key operating parameters on the performance of CDTPC-ARC. Secondly, a comparative study on the proposed CDTPC-ARC and the existing CDTPC-DT (consisting of CDTPC with regenerator and CDTPC without regenerator) under the same waste heat conditions shows that CDTPC-ARC can produce approximately constant net power output (Ẇnet) when Tcw = 18-36 °C, while CDTPC-DT can't operate in the transcritical power cycle when Tcw ⩾ 26.1 °C. Finally, parametric optimization is performed to achieve the maximum Ẇnet of the combined cycles by using genetic algorithms (GA). Results show that CDTPC-ARC can produce more Ẇnet and have a larger recycle efficiency compared with CDTPC-DT when Tcw > 20 °C. When Tcw = 25 °C, Ẇnet,op of CDTPC-ARC is 14.6-20.2% higher than that of CDTPC-DT and the corresponding ηrec is 9.8-25.5% higher than that of CDTPC-DT. In addition, economic performance comparison between the two cycles is performed. The results show that CDTPC-ARC has better economic performance.