不同工质的有机朗肯循环系统变工况特性对比研究

Focusing on the problem that engine loads frequently vary in distributed energy system, and the traditional working fluid selection is only on the basis of the rated engine working condition, the working fluid selection based on off-design performance is investigated in this paper. A model of working fluid selection consisted of system design parameters, off-design simulation, thermal-economic analysis is established by MATLAB. Then, the effects of engine working conditions on the cycle performance are studied and the thermal-economic performance analysis of ORC using eight potentially applicable working fluids is conducted according to the all-day electricity demand of a hotel. The results show that water is more suitable for waste heat recovery under high engine working load, while toluene shows its advantage for the low loading conditions. Electricity production cost E^O and depreciated payback period D^O of water, taking into account changing operating conditions, are 0.131 ＄•(kW•h)^-1 and 8.08 years E^O and D^O of toluene are 0.127 ＄•(kW•h)^-1and 6.75 years, respectively. These results indicate that water is suitable for the building types with steady electricity demand, while toluene is suggested for the building types with transient electricity demand.